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Showing papers in "Journal of Refractive Surgery in 2006"


Journal ArticleDOI
TL;DR: Corneal higher order aberrations, especially coma-like aberration, are significantly higher in eyes with keratoconus than normal eyes.
Abstract: PURPOSE To use the anterior corneal surface higher order aberrations as a tool to detect and grade keratoconus using corneal map analysis videokeratoscopy. METHODS A prospective observational comparative study of 80 eyes was performed. The eyes were divided into two groups. Group A comprised 40 eyes of 20 asymptomatic individuals with no ocular pathology. Mean sphere was -0.03 diopters (D) (range: +0.75 to -0.75 D), mean cylinder was -0.27 D, mean average K was 43.28 D, and mean uncorrected visual acuity (UCVA) was 1.01. Group B comprised 40 eyes of 25 patients with keratoconus. Mean sphere was -3.70 D (range: +2.00 to -10.00 D), mean cylinder was -3.82 D, mean average K was 49.29, and mean best spectacle-corrected visual acuity (BSCVA) was 0.61. RESULTS In group A, mean root-mean-square (RMS) of spherical (Z4 and Z6), coma-like (Z3, Z5, and Z7), and higher order aberrations (Z3-7) were 0.38 microm, 0.35 microm, and 0.52 microm, respectively. In group B, mean RMS of spherical, coma-like, and higher order aberrations were 1.06 microm, 2.90 microm, and 3.14 microm, respectively, for a 6.0-mm simulated pupil diameter. Mean RMS differences between the two groups were 0.68 microm (P < or = .0002), 2.55 microm (P < or = .0001), and 2.61 microm (P < or = .0001) for spherical, coma-like, and total higher order aberrations, respectively. In group B, according to Amsler-Krumeich classification, the mean RMS of coma-like aberration was 1.87 microm in grade I (14 eyes), 2.97 microm in grade II (11 eyes), 3.46 microm in grade III (12 eyes), and 5.20 microm in grade IV (3 eyes). CONCLUSIONS Corneal higher order aberrations, especially coma-like aberrations, are significantly higher in eyes with keratoconus than normal eyes. Coma-like aberrations, with the aid of a corneal aberrometry map, are good indicators for early detection and grading of keratoconus.

377 citations


Journal ArticleDOI
TL;DR: Treatment with 0.002% mitomycin C for 12 seconds to 1 minute appears to be just as effective as higher concentrations for longer duration in the rabbit model, however, a persistent decrease in keratocyte density in the anterior stroma could be a warning sign for future complications and treatment should be reserved for patients with significant risk of developing haze after PRK.
Abstract: Photorefractive keratectomy (PRK) has proven to be a safe and effective procedure to correct low to moderate levels of myopia, hyperopia, or astigmatism. It continues to represent a good alternative to LASIK for many patients, and in some situations, PRK remains the procedure of choice.1 However, PRK continues to have downsides, including increased postoperative pain, a stronger healing response, and most significantly, the possibility of subepithelial corneal opacity or “haze” formation following corrections for high myopia.2,3 The native conformation of the extracellular matrix is altered after PRK. Along with changes in cellular density and phenotype, there is variable production of disorganized extracellular matrix components and generation of myofibroblasts.4 The end result is a decrease in tissue transparency associated with subepithelial corneal haze, which in some patients, is clinically significant. Several different clinical factors likely contribute to haze formation including the depth of ablation, delayed epithelial healing, and the smoothness of the stromal surface after the ablation.5,6 Recent studies have confirmed that postoperative smoothness of the stromal surface is an important factor contributing to subepithelial haze formation.7 In addition, different modulators of the corneal wound healing response and potential medications have been suggested for treatment.8–11 The use of topical mitomycin C during surface ablation procedures has gained considerable attention over the past few years. The mitomycins are potent antibiotics that belong to the family of anti-tumor quinolones.12 In 1956, mitomycin A and B were isolated from the broth of Streptomyces caespitosus, and shortly thereafter mitomycin C was discovered.12 Mitomycin C forms a covalent linkage with deoxyribonucleic acid (DNA) and inhibits DNA synthesis, functioning as a powerful alkylating agent.12,13 At high concentrations, cellular RNA and protein synthesis can also be suppressed.12,13 As a consequence of these cyclostatic effects, mitomycin C is believed to trigger apoptosis and inhibit proliferation of virtually all cells which it enters in sufficient concentrations, including corneal epithelial cells, stromal cells, endothelial cells, conjunctival cells, Tenon’s capsule fibroblasts, and retinal pigment epithelial cells.14–17 The potent effects of mitomycin C on cell replication during the wound healing response gained the attention of vision researchers and its potential benefits in preventing or inhibiting scar formation suggested several possible applications to clinicians. Watanabe et al18 demonstrated that conjunctival cell replication was markedly inhibited by the topical administration of mitomycin C, suggesting potential applications during trabeculectomy surgery. Topical mitomycin C treatment has also been used in the treatment of recurrent pterygium and conjunctival and corneal intraepithelial neoplasia. Subsequently, topical mitomycin C treatment was proposed as an alternative therapy for corneas with previous scar formation secondary to refractive surgical procedures.19 In 1991, Talamo et al20 suggested the use of topical mitomycin C as a modulator of the corneal wound healing response after excimer laser photoablation. These investigators reported that rabbits treated with mitomycin C following laser ablation had markedly reduced formation of subepithelial collagen. Majmudar et al19 first proposed the use of mitomycin C to treat patients with subepithelial fibrosis secondary to previous PRK and radial keratotomy. These authors reported a significant improvement in corneal clarity with a single, 2-minute intraoperative application of 0.02% mitomycin C. Intraoperative use of topical mitomycin C was subsequently used prophylactically to prevent subepithelial haze formation following PRK. Carones et al21 reported a statistically significant decrease in subepithelial haze formation and more accurate refractive outcomes after the prophylactic use of 0.02% mitomycin C during PRK in a group of 60 patients with a spherical equivalent between −6.0 and −10.0 diopters (D) of myopia. Since these early reports, many clinicians have begun using mitomycin C prophylactically—even for low corrections. However, several questions regarding the optimal dosage and exposure time and the long-term safety and efficacy of topical mitomycin C treatment remain unanswered. Even the primary mechanism of action of mitomycin C in the cornea remains uncertain. The purpose of this study was to examine the effect of topical mitomycin C used at different concentrations and for varying exposure times on corneal cells in situ and the efficacy of prophylactic and therapeutic mitomycin C treatments on subepithelial corneal haze following PRK for high myopia in a rabbit model.

168 citations


Journal ArticleDOI
TL;DR: Central presbyLASIK may be used to provide improvement in functional near vision in patients with presbyopia associated with low and moderate hyperopia, however, factors involved in the loss of BSCVA in some cases and loss in vision quality should be further clarified prior to its general use.
Abstract: PURPOSE To investigate central multifocal presbyLASIK based on the creation of a central hyperpositive area METHODS Twenty-five patients (50 eyes) underwent presbyLASlK in an open-label, prospective, non-comparative pilot study Mean patient age was 58 years (range: 51 to 68 years), mean preoperative spherical equivalent refraction was +16 +/- 063 diopters (D) (range: +050 to +300 D), and mean spectacle near addition was +227 +/- 037 D (range: +175 to +300 D) The ablation pattern was performed with proprietary software from Technovision using an H Eye Tech excimer laser platform RESULTS Mean postoperative spherical equivalent refraction was -037 +/- 055 D (range: -150 to + 100 D) and mean spectacle near addition was +172 +/- 034 D (range: +125 to +225 D) After 6 months, 16 (64%) patients achieved a distance uncorrected visual acuity (UCVA) of > or = 20/20 and 18 (72%) patients achieved a near UCVA of > or = 20/40 Seven (28%) patients lost a maximum of 2 lines of best spectacle-corrected visual acuity (BSCVA) The safety index for distance was 098 binocular and for near was 099 binocular After 6 months, no significant change was noted in contrast sensitivity at 15 cycles/degree A significant mean reduction was found at spatial frequencies of 3, 6, 12, and 18 cycles/degree (P<001) There was a significant change in corneal aberrations after surgery The coefficients for coma increased and the coefficients for spherical aberrations decreased A significant decrease was noted in point spread function values (P=0018) CONCLUSIONS Central presbyLASIK may be used to provide improvement in functional near vision in patients with presbyopia associated with low and moderate hyperopia However, factors involved in the loss of BSCVA in some cases and loss in vision quality should be further clarified prior to its general use

142 citations


Journal ArticleDOI
TL;DR: The QIRC is an effective outcome measure for quality of life impact of refractive correction, particularly in spectacle wearers, and contact lens wearers had significantly better QIRC score than spectacle wearer.
Abstract: PURPOSE To demonstrate the use of the Quality of Life Impact of Refractive Correction (QIRC) questionnaire for comparing the quality of life of pre-presbyopic individuals with refractive correction by spectacles, contact lenses, or refractive surgery METHODS The 20-item QIRC questionnaire was administered to 104 spectacle wearers, 104 contact lens wearers, and 104 individuals who had undergone refractive surgery (N = 312) These groups were similar for gender, ethnicity, socioeconomic status, and refractive error The main outcome measure was QIRC overall score (scaled from 0 to 100), a measure of refractive correction related quality of life Groups were compared for overall QIRC score and on each question by analysis of variance, adjusted for age, with post hoc significance testing (Sheffe) RESULTS On average, refractive surgery patients scored significantly better (mean QIRC score 502 +/- 63, F(2,309) = 1518, P < 001) than contact lens wearers (467 +/- 55, post hoc P < 001) who were in turn significantly better than spectacle wearers (441 +/- 59, post hoc P < 01) Convenience questions chiefly drove the differences between groups, although functioning, symptoms, economic concerns, heath concerns, and well being were also important Spectacle wearers with low strength prescriptions (4618 +/- 505) scored significantly better than those with medium strength prescriptions (4274 +/- 608, F(2,190) = 366, P < 05, post hoc P < 05) A small number (n = 7, 67%) of refractive surgery patients experienced postoperative complications, which impacted quality of life (3786 +/- 213) CONCLUSIONS Quality of life was lowest in spectacle wearers, particularly those with higher corrections Contact lens wearers had significantly better QIRC score than spectacle wearers Refractive surgery patients scored significantly better than both However, this was accompanied by a small risk of poor quality of life due to postoperative complications The QIRC is an effective outcome measure for quality of life impact of refractive correction

133 citations


Journal ArticleDOI
TL;DR: Centrally, the total cornea, epithelium, and stroma were thinner in individuals with keratoconus than in normal individuals, and ultrasonic pachymetry produced the highest corneal thickness readings in the center and apex, compared to Orbscan II and OCT.
Abstract: Purpose To compare corneal thickness measurements in individuals with keratoconus using optical coherence tomography (OCT), Orbscan II, and ultrasonic pachymetry and to measure epithelial and stromal thickness in these individuals using OCT. Methods Twenty individuals with keratoconus and 20 controls (without keratoconus) were enrolled. The Orbscan II was used to locate the steepest area of the cornea, which was taken to represent the cone apex. Each instrument was used to obtain four total corneal thickness measurements-from the cone apex, corneal center, mid-nasal, and mid-temporal cornea. Optical coherence tomography scans were analyzed to provide epithelial and stromal thickness readings. Results In individuals with keratoconus, mean central corneal thickness (CCT) measured by ultrasonic pachymetry, Orbscan, and OCT was 494.2 +/- 50.0 microm, 438.6 +/- 47.7 microm, and 433.5 +/- 39.7 microm, respectively. The central keratoconic cornea was 57.7 microm thinner than the normal cornea (post-hoc P .05). Conclusions Ultrasonic pachymetry produced the highest corneal thickness readings in the center and apex, compared to Orbscan II and OCT. Centrally, the total cornea, epithelium, and stroma were thinner in individuals with keratoconus than in normal individuals.

124 citations


Journal ArticleDOI
TL;DR: Inserting INTACS using the femtosecond laser to create the channels is as effective as using the mechanical spreader and both groups showed significant reduction in average keratometry, spherical equivalent refraction, BSCVA, UCVA, surface regularity index, and surface asymmetry index.
Abstract: Purpose To determine the efficacy of INTACS insertion using a femtosecond laser in the treatment of keratoconus and to compare it to the technique using a mechanical spreader. Methods INTACS were inserted in 10 eyes using the mechanical spreader to create the channels and subsequently on another 20 eyes using the femtosecond laser. Uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), manifest refraction, and corneal topography were measured prior to surgery, at 6 months (femtosecond group), and 1 year (mechanical group). Pre- and postoperative data were analyzed to determine changes in the above parameters. Results Both groups showed significant reduction in average keratometry (K), spherical equivalent refraction, BSCVA, UCVA, surface regularity index (SRI), and surface asymmetry index (SAI). The laser group performed better in all parameters except change in SRI. Results of the laser versus the mechanical spreader were as follows: reduction in spherical equivalent refraction (3.98 vs 2.96), change in average K (2.91 vs 2.52), improvement in UCVA (4.13 vs 3.63), improvement in BSCVA (3.92 vs 1.63), change in SRI (0.37 vs 0.64), and change in SAI (1.00 vs 0.70). Statistical analysis, however, did not reveal any statistically significant differences between the two groups for any single parameter studied. The biggest improvement in the laser group versus the mechanical group was BSCVA (P=.09). Overall success, defined as contact lens or spectacles tolerance, was 85% in the laser group and 70% in the mechanical group. Conclusions Inserting INTACS using the femtosecond laser to create the channels is as effective as using the mechanical spreader.

112 citations


Journal ArticleDOI
TL;DR: When compared to two commonly used mechanical microkeratomes, mean achieved flap thickness was more reproducible with the IntraLase FS laser, reducing the comparative risk of overly thick flaps.
Abstract: PURPOSE To compare flap thickness reproducibility of the femtosecond laser and two mechanical microkeratomes. METHODS Flap thickness for all eyes was measured as the difference between the preoperative (day of surgery) full corneal thickness and post-flap creation central stromal bed thickness using ultrasonic pachymetry. Flap thickness values produced by three different microkeratome systems were compared for accuracy and reproducibility. RESULTS For 99 flaps created using the IntraLase FS laser with an intended thickness of 110 microm, the mean achieved thickness was 119 +/- 12 microm (range: 82 to 149 microm). In 100 eyes treated with the Moria LSK-1 microkeratome with an intended flap thickness of 160 microm, the mean achieved thickness was 130 +/- 19 microm (range: 71 to 186 microm). In 135 eyes treated with the Moria M2 microkeratome with an intended flap thickness of 130 microm, mean thickness was 142 +/- 24 microm (range: 84 to 203 microm). The standard deviation and range of corneal flap thickness created with the IntraLase FS laser was significantly smaller than either mechanical microkeratome (P < .0001). CONCLUSIONS When compared to two commonly used mechanical microkeratomes, mean achieved flap thickness was more reproducible with the IntraLase FS laser, reducing the comparative risk of overly thick flaps.

110 citations


Journal ArticleDOI
TL;DR: The autologous serum eye drops group showed prolongation of the tear BUT and a reduction in rose bengal staining score and no differences were noted in the subjective scores for dryness between the autOLOGous serumEye drops and artificial tears groups.
Abstract: Purpose To evaluate the efficacy of autologous serum eye drops for dry eye after LASIK in a prospective, randomized study. Methods Fifty-four eyes of 27 male patients who underwent LASIK were divided into two groups; patients who used autologous serum eye drops and those who used artificial tears postoperatively. Schirmer test with anesthesia, tear break-up time (BUT), and rose bengal and fluorescein staining for the ocular surface were prospectively compared between the groups. All values were also compared before and after surgery (at 1 week [except for Schirmer test], 1 month, 3 months, and 6 months) in each group. Results Tear BUT was greater in the autologous serum eye drops group than in the artificial tears group at 6 months postoperatively. Rose bengal score was lower in patients using autologous serum eye drops than in patients using artificial tears at 1 month and 3 months postoperatively. No significant difference was noted between patients using autologous serum eye drops and patients using artificial tears in the value of Schirmer test with anesthesia and fluorescein scores. In the autologous serum eye drops group, tear BUT was increased at 3 months after LASIK, rose bengal score was lower at 1 month and 3 months, and fluorescein score was lower at 1 month after LASIK compared to preoperative values, respectively. In the artificial tears group, all values (Schirmer test, tear BUT, rose bengal score, and fluorescein score) showed no differences between before and after LASIK. No differences were noted in the subjective scores for dryness between the autologous serum eye drops and artificial tears groups. Conclusions The autologous serum eye drops group showed prolongation of the tear BUT and a reduction in rose bengal staining score.

108 citations


Journal ArticleDOI
TL;DR: Comparing the astigmatism, high order aberrations, and optical quality of the cornea after microincision versus small incision cataract surgery at Eye Center, Zhejiang University, Hangzhou, China shows no significant advantage in reducing corneal high order Aberrations over small incisions.
Abstract: PURPOSE: To compare the astigmatism, high order aberrations, and optical quality of the cornea after microincision (~1.7 mm) versus small incision (~3.2 mm) cataract surgery at Eye Center, Zhejiang University, Hangzhou, China. METHODS: This prospective, randomized clinical study included microincision cataract surgery and small incision cataract surgery performed on 60 eyes. Corneal astigmatism and higher order aberrations to the sixth order were measured using the NIDEK OPD-Scan aberrometer/topographer 1 month after surgery. To evaluate the optical quality of the cornea, the 0.5 modulation transfer function (MTF) value and 0.1 MTF value within a 5-mm pupil were calculated using OPD-Station software. Statistical analysis assessing the difference between groups was carried out using the independent t test.

104 citations


Journal ArticleDOI
TL;DR: The Astigmatism Project Group is proposed as a standard reference for astigmatic refractive error analyses for the evaluation of safety and effectiveness of laser systems that reshape the cornea.
Abstract: PURPOSE; To develop a minimum set of analyses and a format for presentation of outcomes of astigmatism correction by laser systems that reshape the cornea. METHODS: An Astigmatism Project group was created under the auspices of the American National Standards Institute (ANSI) 280.11 Working Group on Laser Systems for Corneal Reshaping. The Astigmatism Project Group was made up of experts in astigmatism analyses from academia, government, and industry. An extensive literature review was conducted to identify all currently available methodologies for the evaluation of astigmatic outcomes. Project Group members discussed the utility of each method land its specific parameters for evaluating the effectiveness of astigmatism-correcting devices. They gave consideration to unique terminology and analyses required for evaluation of correction of astigmatism by laser systems that reshape the cornea. RESULTS: The Project Group defined a comprehensive list of analysis variables needed for the evaluation of astigmatism-correcting devices and generated mathematical definition for each term. They developed a minimum set of analyses needed for evaluation of astigmatism treatments by laser systems that reshape the cornea. They established methods for calculating the refractive error analysis variables and constructed recommended table and graph formats for data presentation. CONCLUSIONS: This article contains the recommendations of the Astigmatism Project Group of the American National Standards Institute. We propose it as a standard reference for astigmatic refractive error analyses for the evaluation of safety and effectiveness of laser systems that reshape the cornea.

93 citations


Journal ArticleDOI
TL;DR: Corneal confocal microscopy represents a new tool in the diagnosis, clinical evaluation, and follow-up of peripheral diabetic neuropathy, and it is found that diabetes damages corneal nerves, particularly the corNEal sub-basal nerve plexus.
Abstract: PURPOSE: To evaluate the role of corneal confocal microscopy in the diagnosis of morphologic damage of the corneal sub-basal nerve plexus in diabetic patients and to correlate corneal confocal microscopy fi ndings with peripheral diabetic neuropathy. METHODS: Corneal sub-basal nerve plexus parameters were quantifi ed by corneal confocal microscopy in 42 diabetic patients and 27 age-matched controls. The parameters quantifi ed were the number of fi bers, the tortuosity of fi bers, the number of beadings, and the branching pattern of the fi bers. Peripheral neuropathy was also quantifi ed using the Michigan Neuropathy Screening Instrument. RESULTS: The number of fi bers, number of beadings, and branching pattern of fi bers signifi cantly decreases in diabetic patients versus control subjects (P.0001; P.0001; P=.0006, respectively), whereas nerve tortuosity signifi cantly increases (P.0001). The same corneal sub-basal nerve plexus parameters show a statistical trend, suggesting progression of corneal neuropathy with peripheral diabetic neuropathy. CONCLUSIONS: Corneal confocal microscopy represents a new tool in the diagnosis, clinical evaluation, and follow-up of peripheral diabetic neuropathy. This study found that diabetes damages corneal nerves, particularly the corneal sub-basal nerve plexus. This damage may be easily and accurately documented using corneal confocal microscopy. [J Refract Surg. 2006;22: S1047-S1052.]

Journal ArticleDOI
TL;DR: A new IOL power calculation formula was developed and used in 20 eyes that previously underwent refractive surgery and compared the results to other formulas, obtaining encouraging results.
Abstract: PURPOSE: When calculating the power of an intraocular lens (IOL) with conventional methods in eyes that have previously undergone refractive surgery, in most cases the power is inaccurate. To minimize these errors, a new IOL power calculation formula was developed. METHODS: A theoretical formula empirically adjusted two variables: 1) the corneal power and 2) the anterior chamber depth (ACD). From the average curvature of the entrance pupil area, weighted according to the Stiles–Crawford effect, the corneal power is calculated by using a relative keratometric index that is a function of the actual corneal curvature, type of keratorefractive surgery, and induced refractive change. Anterior chamber depth is a function of the preoperative ACD, lens thickness, axial length, and the ACD constant. We used our formula in 20 eyes that previously underwent refractive surgery (photorefractive keratectomy [n=6], laser subepithelial keratomileusis [n=3], laser in situ keratomileusis [n=6], and radial keratotomy [n=5]) and compared our results to other formulas. RESULTS: Mean postoperative spherical equivalent refraction was � 0.26 diopters (D) (standard deviation [SD] 0.73, range: � 1.25 to � 1.58 D) using our formula, � 2.76 D (SD 1.03, range: � 0.94 to � 4.47 D) using the SRK II, � 1.44 D (SD 0.97, range: � 0.05 to � 4.01 D) with Binkhorst, 1.83 D (SD 1.00, range: � 0.26 to � 4.21 D) with Holladay I, and � 2.04 D (SD 2.19, range: � 7.29 to � 1.62 D) with Rosa’s method. With our formula, 60% of absolute refractive prediction errors were within 0.50 D, 80% within 1.00 D, and 93% within 1.50 D. CONCLUSIONS: In this fi rst series of patients, we obtained encouraging results. With a greater number of cases, all statistical adjustments related to the different types of surgery should be improved. [J Refract Surg. 2006;22:187-199.] W ith the advent of keratorefractive surgery, more and more patients undergoing cataract surgery with intraocular lens (IOL) implantation have previously undergone some type of refractive surgery. In these cases, no particular technical diffi culty exists when performing cataract surgery; however, the IOL power is usu

Journal ArticleDOI
TL;DR: This model together with high-precision microkeratomes, preoperative pachymetry, and knowledge of laser ablation precision would enable surgeons to determine the specific imprecision of RST prediction for individual LASIK cases and minimize the risk of ectasia.
Abstract: Purpose To derive a statistical model to estimate the rate of excessive keratectomy depth below a selected cut-off residual stromal thickness (RST) given a minimum target RST and specific Clinical Protocol; apply the model to estimate the RST below which ectasia appears likely to occur and back-calculate the safe minimum target RST that should be used given a specific Clinical Protocol. Methods Myopia and corneal thickness distribution were modeled for a population of 5212 eyes that underwent LASIK. The probability distribution of predicted target RST error (Part I) was used to calculate the rate of excessive keratectomy depth for this series. All treatments were performed using the same Clinical Protocol; one surgeon, Moria LSK-One microkeratome, NIDEK EC-5000 excimer laser, Orbscan pachymetry, and a minimum target RST of 250 microm--the Vancouver Clinical Protocol. The model estimated the RST below which ectasia appears likely to occur and back-calculated the safe minimum target RST. These values were recalculated for a series of microkeratomes using published flap thickness statistics as well as for the Clinical Protocol of one of the authors-the London Clinical Protocol. Results In the series of 5212 eyes, 6 (0.12%) cases of ectasia occurred. The model predicted an RST of 191 microm for ectasia to occur and that a minimum target RST of 329 microm would have reduced the -rate of ectasia to 1: 1,000,000 for the Vancouver Clinical Protocol. The model predicted that the choice of microkeratome varied the rate of ectasia between 0.01 and 11,623 eyes per million and the safe minimum target RST between 220 and 361 microm. The model predicted the rate of ectasia would have been 0.000003: 1,000,000 had the London Clinical Protocol been used for the Vancouver case series. Conclusions There appears to be no universally safe minimum target RST to assess suitability for LASIK largely due to the disparity in accuracy and reproducibility of microkeratome flap thickness. This model may be used as a tool to evaluate the risk of ectasia due to excessive keratectomy depth and help determine the minimum target RST given a particular Clinical Protocol.

Journal ArticleDOI
TL;DR: In young patients with unilateral cataract surgery, unilateral multifocal IOL implantation provides satisfactory visual acuity and may be considered an alternative treatment option in this patient population.
Abstract: PURPOSE: To compare the visual performance in the pseudophakic eye and the phakic eye in four patients who underwent unilateral intraocular lens (IOL) implantation. METHODS: Four patients presenting with unilateral cataract underwent ReSTOR (Alcon Laboratories, Ft Worth, Tex) IOL implantation in their nondominant eye, targeting emmetropia. RESULTS: Uncorrected near visual acuity was >20/32 in all operated eyes and best spectacle-corrected distance visual acuity was 20/16 for two eyes, 20/25 for one eye, and 20/32 for one eye. Reading speed was similar between the eyes, but not for critical print size. Contrast sensitivity was lower in the pseudophakic eyes. Wavefront analysis showed no considerable difference in total high order aberrations, coma, and spherical aberration between eyes for all patients. CONCLUSIONS: In young patients with unilateral cataract surgery, unilateral multifocal IOL implantation provides satisfactory visual acuity and may be considered an alternative treatment option in this patient population.

Journal ArticleDOI
TL;DR: Photorefractive keratectomy and LASIK were both effective and safe in the correction of hyperopia, however, PRK manifested an initial temporary myopic overshoot followed by a hyperopic regression over 24-month follow-up (P < .01), whereas LASik was associated with a faster refractive stability.
Abstract: PURPOSE To evaluate the efficacy and safety of photorefractive keratectomy (PRK) and LASIK in the correction of hyperopia. METHODS A retrospective study was conducted on 100 eyes of 56 patients with a mean hyperopia of +2.85 +/- 1.1 diopters (D) undergoing PRK and 100 eyes of 50 patients with a mean hyperopia of +4.49 +/- 1.2 D undergoing LASIK. A Zeiss Meditec MEL 70 G scan laser was used. RESULTS After 24-month follow-up in the PRK group (100 eyes), the mean manifest refractive spherical equivalent (MRSE) was +0.34 +/- 0.92 D (36% +/- 0.5 D). Mean uncorrected visual acuity (UCVA) was 0.87 +/- 0.1; 8 (8%) eyes gained 1 line, 80 (80%) eyes had no loss or gain of lines, 10 (10%) eyes lost 1 line, and 2 (2%) eyes lost 2 lines. In the LASIK group (100 eyes), at 24-month follow-up, the mean MRSE was +0.29 +/- 0.66 D (70% +/- 0.5 D). Mean UCVA was 0.89 +/- 0.1; 6 (6%) eyes gained 2 lines, 10 (10%) eyes gained 1 line, 78 (78%) eyes had no loss or gain of lines, and 6 (6%) eyes lost 1 line. CONCLUSIONS Photorefractive keratectomy and LASIK were both effective and safe in the correction of hyperopia. However, PRK manifested an initial temporary myopic overshoot followed by a hyperopic regression over 24-month follow-up (P < .01) whereas LASIK was associated with a faster refractive stability.

Journal ArticleDOI
TL;DR: Binocular function deteriorates more than monocular function after LASIK, and this deterioration increases as the interocular differences in aberrations and corneal shape increase.
Abstract: PURPOSE: To analyze binocular visual function after LASIK. METHODS: Eye aberrometry and corneal topography was obtained for both eyes in 68 patients (136 eyes). To evaluate visual performance, monocular and binocular contrast sensitivity function and disturbance index for quantifying halos were measured. Tests were performed under mesopic conditions. RESULTS: Binocular summation and disturbance index diminished signifi cantly (P.0001) after LASIK with increasing interocular differences in corneal and eye aberrations. Binocular visual deterioration was greater than monocular deterioration for contrast sensitivity function and disturbance index. CONCLUSIONS: Binocular function deteriorates more than monocular function after LASIK. This deterioration increases as the interocular differences in aberrations and corneal shape increase. Improvements in ablation algorithms should minimize these interocular differences. [J Refract Surg. 2006;22:679-688.]

Journal ArticleDOI
TL;DR: Topography-guided LASIK and PRK resulted in a significant reduction of refractive cylinder and increase of UCVA, without a significant loss of BSCVA, in patients with small hyperopic and myopic excimer laser optical zones.
Abstract: PURPOSE To evaluate the feasibility, safety, and predictability of correcting high irregular astigmatism in symptomatic eyes with the use of topography-guided photoablation METHODS In a prospective, non-comparative case series, 16 consecutive symptomatic eyes of 11 patients with small hyperopic and myopic excimer laser optical zones, decentered and irregular ablation after corneal graft, and corneal scars were operated Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest and cycloplegic refraction, and corneal topography, with asphericity and regularity, were analyzed LASIK (n = 10) and photorefractive keratectomy (n = 6) were performed using the ALLEGRETTO WAVE excimer laser and T-CAT software (Topography-guided Customized Ablation Treatment; WaveLight Laser Technologie AG, Erlangen, Germany) RESULTS In the LASIK group, UCVA improved from 081 +/- 068 IogMAR (20/130) (range: 02 to 20) to 029 +/- 021 logMAR (20/39) (range: 01 to 07) at 6 months In the PRK group, mean UCVA improved from 089 +/- 087 IogMAR (20/157) (range: 01 to 20) to 042 +/- 035 logMAR (20/53) (range: 01 to 10) at 6 months Best spectacle-corrected visual acuity did not change significantly in either group One PRK patient lost one line of BSCVA Refractive cylinder for the LASIK group improved from -253 +/- 171 diopters (D) (range: -075 to -575 D) to -128 +/- 099 D (range: 0 to -250 D) at 6 months Refractive cylinder in the PRK group improved from -221 +/- 211 D (range: -025 to -550 D) to -110 +/- 042 D (range: -050 to -150 D) Index of surface irregularity showed a decrease from 60 +/- 12 (range: 46 to 89) to 50 +/- 9 (range: 32 to 63) at 6 months in the LASIK group whereas no significant change was noted in the PRK group Subjective symptoms, such as glare, halos, ghost images, starbursts, and monocular diplopia, were not present postoperatively CONCLUSIONS Topography-guided LASIK and PRK resulted in a significant reduction of refractive cylinder and increase of UCVA, without a significant loss of BSCVA

Journal ArticleDOI
TL;DR: Photorefractive keratectomy with the Summit UV200 excimer laser effectively reduced myopia and showed good refractive stability from year 2 to 12 with good patient satisfaction.
Abstract: PURPOSE To evaluate long-term safety and stability in a group of myopic patients who underwent photorefractive keratectomy (PRK) > or =12 years ago. METHODS Myopic PRK was performed on 120 eyes of 80 patients using the Summit UV200 excimer laser with a 5-mm ablation zone. Of the original group, most of whom were followed for > or =2 years (mean 2.6 +/- 1.7 years), 34 patients (58 eyes) returned at 12 years (mean 12.7 +/- 0.79 years) and had refractive stability, refractive predictability, best spectacle-corrected visual acuity (BSCVA), corneal haze, and subjective patient symptoms, such as glare/halos, recorded. RESULTS Preoperative mean refractive spherical equivalent (MRSE) ranged from -1.75 to -7.25 diopters (D) and astigmatism from 0.00 to 1.50 D. All eyes underwent a change in manifest refraction over 12 years. At 2 years, MRSE was -0.27 +/- 0.55 D and at 12 years was -0.58 +/- 0.72 D. In 87.9% of eyes, the level of preoperative BSCVA was maintained or improved, whereas 34.5% of eyes gained one line, and 12.1% lost one line of BSCVA. Uncorrected visual acuity > or = 20/20 was noted in 67% of eyes, whereas 62.1% were within +/- 0.50 D of emmetropia. Trace haze was noted in 17.2% of eyes at 12 years. One patient had a rhegmatogenous retinal detachment, but this was unlikely due to the PRK procedure. With respect to the small optical zone, 14 (41.1%) patients had night visual problems, particularly halos, which were severe in 2.7%. All patients questioned stated they would have the procedure done again. CONCLUSIONS Photorefractive keratectomy with the Summit UV200 excimer laser effectively reduced myopia and showed good refractive stability from year 2 to 12 with good patient satisfaction.

Journal ArticleDOI
TL;DR: Intraocular pressure measurements after LASIK for the correction of myopia are inaccurate as a consequence of changes in CCT, corneal curvature, andCorneal flap stability.
Abstract: PURPOSE To create a correction formula to determine the real intraocular pressure (IOP) after LASIK considering the altered corneal thickness, corneal curvature, and corneal stability. METHODS This prospective clinical trial comprised 101 eyes of 59 patients (34 women and 25 men) that underwent LASIK with a mean preoperative spherical equivalent refraction of -6.3 +/- 2.17 diopters (D) (-3.0 to -11.5 D). Mean patient age was 32 +/- 9 years. Preoperatively and 6 months postoperatively, IOP (by Goldmann applanation tonometry), keratometry (by topography), and central corneal thickness (CCT) (by ultrasound pachymetry) were evaluated. These parameters were measured in all patients between 8 and 11 o'clock in the morning. RESULTS Due to the LASIK procedure, IOP was reduced from 16.5 +/- 2.1 mmHg (range: 12 to 22 mmHg) to 12.9 +/- 1.9 mmHg (range: 8 to 16 mmHg). Multiple linear regression analysis of the IOP values before and after LASIK showed a significant correlation between the measured IOP and CCT and keratometry values (R2=0.631; P<.001). After LASIK, the biomechanical bending strength of the cornea is reduced by the cut so that the measured IOP must be additionally corrected by 0.75 mmHg. An equation containing all three changes is given: IOP (real) = IOP (measured) + (540-CCT)/71 + (43-K-value)/2.7 + 0.75 mmHg. CONCLUSIONS Intraocular pressure measurements after LASIK for the correction of myopia are inaccurate as a consequence of changes in CCT, corneal curvature, and corneal flap stability. After LASIK, the measured IOP should be corrected to avoid false low IOP applanation readings.

Journal ArticleDOI
TL;DR: Late keratectasia may follow LASIK for low myopia despite a thorough preoperative work-up, and this case is reported to be a rare case of late bilateral ectasia developing after LASik forLow myopia without preoperative risk factors.
Abstract: Purpose To report a rare case of late bilateral ectasia developing after LASIK for low myopia without preoperative risk factors. Methods A 21-year-old man underwent bilateral uneventful LASIK for low myopia of -2.75 diopters in both eyes. Preoperative corneal pachymetry was 531 microm in the right eye and 526 microm in the left eye. The total ablation depth was 46.8 microm in the right eye and 42.2 microm in the left eye. Preoperative corneal topography was normal and did not reveal forme fruste keratoconus. Results Twenty-four months postoperatively, the patient developed bilateral inferior keratectasia of +0.50 -3.00 x 72 degrees in the right eye and +1.00 -2.75 x 99 degrees in the left eye. Conclusions Late keratectasia may follow LASIK for low myopia despite a thorough preoperative work-up.

Journal ArticleDOI
TL;DR: A positive correlation between corneal haze and tear fluid TGF-beta1 levels on the first postoperative day suggest a possible mechanism for the observed difference between LASEK and epi-LASIK.
Abstract: Purpose To compare the incidence and degree of corneal haze formation following laser subepithelial keratomileusis (LASEK) and epithelial laser in situ keratomileusis (epi-LASIK), and examine its correlation with tear film transforming growth factor-beta1 (TGF-beta1) levels. Methods This prospective, interventional, clinical trial included 20 eyes (20 patients) randomly assigned to undergo LASEK or epi-LASIK. The level of TGF-beta1 in tear fluid was measured preoperatively and 1, 3, and 5 days postoperatively. Corneal haze was graded at 1 and 3 months after surgery, and the relationship with TGF-beta1 levels was determined. Results Mean preoperative spherical equivalent refraction was -4.50 +/- 1.44 diopters (D) (range: -1.50 to -6.00 D) for LASEK eyes and -4.90 +/- 1.26 D (range: -1.75 to -6.00 D) for epi-LASIK eyes. Although mean corneal haze scores at 1 month were significantly higher in LASEK-treated eyes than in epi-LASIK treated eyes (P=.031), these scores were similar at 3 months (P=.608). Tear fluid TGF-beta1 levels were similar in LASEK and epi-LASIK eyes before surgery (P=.458) and significantly higher in the LASEK group at 1, 3, and 5 days postoperatively (P=.015, P=.023, and P=.039, respectively). A positive correlation was noted between tear TGF-beta1 levels on the first postoperative day and the degree of corneal haze at 1 month (r=0.501, P=.016). Conclusions Less corneal haze was noted after epi-LASIK than LASEK. A positive correlation between corneal haze and tear fluid TGF-beta1 levels on the first postoperative day suggest a possible mechanism for the observed difference.

Journal ArticleDOI
TL;DR: This study helps establish ocular aberration standards for Chinese refractive surgery candidates by describing the characteristics of higher order ocular aberrations of adult Chinese eyes with myopia.
Abstract: PURPOSE To describe the characteristics of higher order ocular aberrations of adult Chinese eyes with myopia. METHODS Higher order aberrations in consecutive right eyes of 166 Chinese patients with myopia who enrolled for preoperative assessment for LASIK were retrospectively reviewed. Wavefront aberrations were measured with the Bausch & Lomb Zywave over a 6-mm dilated pupil. The correlations between higher order aberrations and myopia, astigmatism, and age, respectively, were analyzed. RESULTS Mean patient age was 32.1 +/- 6.2 years, the mean refractive error was sphere -5.23 +/- 1.79 diopters (D) and cylinder -1.29 +/- 0.98 D. The mean of the total higher order root-mean-square (RMS) (third to fifth order) was 0.49 +/- 0.16 microm. Third-order RMS was largest (mean 0.37 +/- 0.16 microm), followed by fourth-order RMS (mean 0.29 +/- 0.11 microm). For individual higher order Zernike coefficients, spherical aberration (C4(0)) predominated with a mean of 0.23 +/- 0.14 microm. No correlation was found between total higher order RMS and myopia or between total higher order RMS and age. Small but statistically significant relationships were found in the following groups: age and vertical primary coma (C3(-1))(r=-0.206, P=.008); age and spherical aberration (C4(0)) (r=0.196, P=.012); and myopia and horizontal trefoil (C3(3)) (r=-0.158, P=.042). CONCLUSIONS Higher order aberrations varied among individuals with myopia. Third-order RMS was the predominant higher order aberration. Spherical aberration and vertical primary coma increased slightly with age. Our study helps establish ocular aberration standards for Chinese refractive surgery candidates.

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TL;DR: Patients treated with the OATz profiles had better visual quality as measured by contrast sensitivity and also had larger effective optical zones as compared with those treated by the conventional ablation profile.
Abstract: PURPOSE To compare a new ablation algorithm termed the optimized aspheric transition zone (OATz) with the conventional laser ablation profile for correction of myopic astigmatism. METHODS LASIK using OATz profile #6 or using conventional ablation profile was performed on 98 eyes of 53 patients (OATz #6 group) and 111 eyes of 66 patients (control #6 group), respectively. Further, LASIK using OATz profile #5 or using the conventional ablation profile was performed on 109 eyes of 58 patients (OATz #5 group) and 109 eyes of 75 patients (control #5 group), respectively. The effective optical zone, uncorrected visual acuity, manifest refraction, aberrations, contrast sensitivity, and patient satisfaction at 3 months postoperatively were compared between the OATz #6 and control #6 groups and between the OATz #5 and control #5 groups. RESULTS The effective optical zones in the OATz #6 group (6.45 +/- 0.29 mm) or OATz #5 group (6.40 +/- 0.21 mm) were significantly larger than those in the control #6 group (6.33 +/- 0.27 mm) or control #5 group (6.26 +/- 0.25 mm) (P < .01), respectively. Uncorrected visual acuity and manifest refraction were similar in all groups. The changes in contrast sensitivity were significant and favored the OATz #6 (P < .01) and OATz #5 groups (P < .05). The patient satisfaction survey found no statistical difference at 3 months postoperatively. CONCLUSIONS Patients treated with the OATz profiles had better visual quality as measured by contrast sensitivity and also had larger effective optical zones as compared with those treated by the conventional ablation profile.

Journal ArticleDOI
TL;DR: Clear corneal tunnel phacoemulsification and IOL implantation guided by corNEal topography can yield better visual acuity by reducing the pre-existing astigmatism and inducing lessCorneal aberrations than conventional temporal cornean tunnel phacemulsifying.
Abstract: PURPOSE: To study changed in comeal astigmatism and high order aberrationsafter clear corneal tunnel phacoemulsification guided by comeal topography. METHODS: All patients were randomly assigned to the test group or the control group. Corneal topography-guided clear corneal tunnel phacoemulsification followed by intraocular lens llOU implantation was performed on 22 eyes of 16 patients in the test group and conventional temporal corneal tunnel phacoemulsification and IOL implantation were performed on 22 eyes of 21 patients in the control group. The corneal astigmatism and high order aberrations were measured using the NIDEK OPD-Scan aberrometer and topographer preoperatively and up to 3 months after surgery. The corneal astigmatism and sixth order root-mean-square (RMS) for corneal coma, trefoil, spherical, secondary coma, and secondary spherical aberrations at 4-mm pupil diameters were compared. RESULTS: Fifteen (69%) eyes in the test group and 8 (36%) eyes in the control group achieved ≥20/25 uncorrected visual acuity 3 months after surgery, which was statistically significant (P<.05). The best spectacle-corrected visual acuitu was ≥20/20 in 14 (63%) eyes in the test group and 10 (45%) eyes in the control group. The mean surgically induced astigmatism in the test group was O.58±0.39 diopters (D) compared with 0.73±0.41 D in the control group. The change in corneal astigmatism from preoperative to 3 months after surgery was -0.17±0.32 D for the test group and 0.10±0.41 D for the control group, which was statistically significant (P<.05). The RMS value of trefoil aberrations increased, and all other aberrations decreased at 3 months after surgery in the test group. The RMS values of all corneal high order aberrations increased in the control group, with the increase in trefoil being statistically significant The comparison of surgically Induced high order aberrations between the two groups showed that corneal coma, trefoil, and secondary corna were significantly different. CONCLUSIONS: Clear corneal tunnel phacoemulsification and IOL implantation guided by corneal topography can yield better visual acuity by reducing the pre-existing astigmatism and inducing less corneal'aberrations than conventional temporal comeal tunnel phaccemulsification.

Journal ArticleDOI
TL;DR: Interface fluid syndrome secondary to steroid-induced elevation of IOP might develop in steroid responders after LASIK with a misleading clinical picture simulating DLK or infectious keratitis.
Abstract: PURPOSE To describe interface corneal edema secondary to steroid-induced elevation of intraocular pressure (IOP) following LASIK METHODS Retrospective observational case series Diffuse interface edema secondary to steroid-induced elevation of IOP was observed after LASIK simulating diffuse lamellar keratitis (DLK) in 13 eyes Mean patient age was 314 +/- 53 years Patients were divided into two groups according to provisional misdiagnosis: DLK group (group 1) comprised 11 eyes and infection group (group 2) comprised 2 eyes (microbial keratitis) Mean follow-up was 81 +/- 05 weeks RESULTS In the DLK group, typical diffuse haze was confined to the interface and extended to the visual axis, impairing vision in all eyes Provisional diagnosis was late-onset DLK and topical steroids were started Repeat examination showed elevated IOP as measured at the corneal center and periphery using applanation tonometry (mean 191 mmHg and 395 mmHg, respectively), causing interface edema with evident interface fluid pockets Steroids were stopped and topical anti-glaucoma therapy was started The interface edema decreased and at the end of follow-up the corneal transparency was restored and IOP dropped to normal values The infection group demonstrated a microbial keratitis-like reaction and underwent flap lifting and interface wound debridement and biopsy with administration of fortified antibiotics and steroids After elevated IOP was detected, steroids and antibiotics were stopped and topical anti-glaucoma therapy was started, resulting in the resolution of the interface edema CONCLUSIONS Interface fluid syndrome secondary to steroid-induced elevation of IOP might develop in steroid responders after LASIK with a misleading clinical picture simulating DLK or infectious keratitis Management includes stopping topical steroids and starting topical antiglaucoma therapy

Journal ArticleDOI
TL;DR: Prophylactic use of intraoperative MMC in LASEK significantly decreases haze incidence and a statistically significant difference was noted in haze intensity between the MMC and no MMC group.
Abstract: PURPOSE To analyze the results of prophylactic intraoperative use of mitomycin C (MMC) in laser epithelial keratomileusis (LASEK). METHODS A retrospective analysis of 30 LASEK cases that received MMC 0.02% intraoperatively (MMC group) was performed and compared to the results obtained in 28 LASEK cases not receiving MMC (no MMC group). Mitomycin C was placed in contact with the ablation zone for 75 seconds with an imbibed microsponge. Both groups received postoperative fluorometholone for 3 months. Preoperative spherical equivalent refraction was -5.72 +/- 2.82 diopters (D) in the MMC group and -5.81 +/- 2.74 D in the no MMC group. Best spectacle-corrected visual acuity was 0.88 +/- 0.12 in the MMC group and 0.88 +/- 0.13 in the no MMC group. RESULTS Spherical equivalent refraction at 6 months postoperatively was +0.11 +/- 0.13 D in the MMC group and +0.09 +/- 0.37 D in the no MMC group. Best spectacle-corrected visual acuity was 0.90 +/- 0.13 in the MMC group and 0.88 +/- 0.13 in the no MMC group. Uncorrected visual acuity (UCVA) > or = 20/40 was obtained in 93.3% of cases in the MMC group and in 89.3% of cases in the no MMC group; UCVA > or = 20/25 was achieved in 76.6% of cases in the MMC group and in 71.4% of cases in the no MMC group. Haze incidence for the MMC group was: trace: 0%, Grades I: 0%, II: 0%, III 0%, IV: 0%, and for the no MMC group: trace: 17.9%, Grades I: 3.6%, II: 0%, III: 0%, IV: 0%. A statistically significant difference (P<.001) was noted in haze intensity between the MMC group and no MMC group. CONCLUSIONS Prophylactic use of intraoperative MMC in LASEK significantly decreases haze incidence.

Journal ArticleDOI
TL;DR: Wavefront aberration data obtained using the NIDEK OPD-Scan, Bausch & Lomb Zywave wavefront aberrometer, and VISX CustomVue wavefront analyzer were compared to compare higher order aberration measurements between optical path difference (OPD) scanning and the Hartmann-Shack method.
Abstract: PURPOSE: To assess the repeatability of measurements of higher order aberrations using three different aberrometers and to compare higher order aberration measurements between optical path difference (OPD) scanning and the Hartmann-Shack method. METHODS: Wavefront aberration data obtained using the NIDEK OPD-Scan, Bausch & Lomb Zywave wavefront aberrometer, and VISX CustomVue wavefront analyzer were compared. A total of 19 subjects were included in the study. The repeatability in each machine was assessed by calculating the difference between measurements and the mean of three consecutive measurements in the same eye. Subsequent analysis of the distribution of these differences yields the mean difference, the standard deviation of the differences, and the 95% confidence interval for repeated measurements, also termed the "repeatablity coefficienet. RESULTS: Repeatability errors in all three machines were found to be low, suggesting that all three machines are reliable in their repeated measurements. Significant differences were demonstrated between OPD scanning and Hartmann-Shack aberrometers. All three machines showed statistically significant differences in several higher order aberration parameters when compared to each other. CONCLUSIONS: The three different aberrometers provided repeatable measurements but statistical differences were noted in the measurement of higher order aberrations when comparing the machines. No instrument was superior over the other and all three were reliable.

Journal ArticleDOI
TL;DR: Pterygia are associated with wavefront aberrations, especially trefoil, but these were largely eliminated by surgery, and earlier excision of pterygium reduces the likelihood of significant residual aberration.
Abstract: PURPOSE: To determine the higher order aberrations at the corneal fi rst surface before and after surgery for pterygium. METHODS: Data were drawn from a longitudinal study of patients undergoing pterygium excision at Royal Victoria Infi rmary, Newcastle upon Tyne, England between September 1998 and May 2004. Corneal topography was taken with the TMS-2 Topographic Modeling System (Computed Anatomy Corp) prior to and 6 months after surgery, exported to VOLPro software v7.08 (Sarver & Associates), and wavefront aberrations were derived for a 5.0-mm pupil using a 10th order Zernike polynomial expansion. Pre- to postoperative changes were assessed for signifi cance using analyses of variance, and the relative risk of signifi cant postoperative aberrations by pterygium size was determined. RESULTS: Satisfactory corneal topography was available on 67 eyes (mean age 53.8±16.7 years [range: 25-86 years]). The root-mean-square (RMS) fi t error in preoperative eyes was 0.150.10 µm. Preoperatively, the total higher order RMS wavefront aberration was 0.940.83 µm. All Zernike modes were elevated, with trefoil being the major contributor 0.520.50 µm. Pterygium excision signifi cantly reduced wavefront aberrations across all modes and orders (F 1,129 =6.7 to 22.6, P.01): total higher order RMS postop 0.450.35 µm. Cases with visually signifi cant postoperative aberrations occurred and were more likely with larger pterygia: relative risk compared to pterygia 1.0 to 1.9 mm was 1.3 for 2.0 to 2.9 mm, 8.5 for 3.0 to 3.9 mm, 13.3 for 4.0 to 4.9 mm, and 10.2 for 5.0 to 5.9 mm. CONCLUSIONS: Zernike polynomial fi tting well describes wavefront aberrations in eyes with pterygia. Pterygia are associated with wavefront aberrations, especially trefoil, but these were largely eliminated by surgery. Earlier excision of pterygia reduces the likelihood of signifi cant residual aberrations. [J Refract Surg. 2006;22:921-925.]

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TL;DR: Hyperopic LASIK using the WaveLight ALLEGRETTO WAVE excimer laser appears to be safe and effective in the correction of low, moderate, and high hyperopia and hyperopic astigmatism.
Abstract: PURPOSE: To evaluate the safety and efficacy of the ALLEGRETTO WAVE excimer laser system (WaveLight Laser Technologie AG, Erlangen, Germany) in LASIK for hyperopia and hyperopic astigmatism. METHODS: One hundred twenty consecutive LASIK cases for hyperopia with or without astigmatism treated with the ALLEGRETTO WAVE excimer laser were prospectively evaluated up to 12 months postoperatively. Patients were allocated into three groups according to their refractive sphere and cylinder: a low hyperopia group, with up to +3.00 diopters (D) sphere and astigmatism ≤+1.00 D (n=52); a moderate hyperopia group with +3.25 to +5.00 D sphere and astigmatism of ≤+1.00 D (n=45); and a high hyperopia/toric group with sphere ≥+5.25 D or cylinder ≥+1.25.D (n=23). Flaps were created with the Moria M2 microkeratome (Moria, Antony, France). Parameters evaluated were pre- and postoperative refractive error, uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), higher order aberration change, and contrast sensitivity. RESULTS: One hundred twelve eyes (93%) were available for follow-up at 12 months. Of the eyes in the low hyperopia group, 92% were within ±0.50 D of the refractive goal. For the moderate sphere group and the high hyperopia/toric group, 79% and 71% of eyes, respectively, were within ±0.50 D of the refractive goal. No eye lost ≥2 lines of BSCVA. An increase in higher order aberrations was noted in the high hyperopia/toric group from 0.47 pm (±0.096) to 0.94 pm (±0.167) (P<.001). No significant changes in higher order aberrations were noted in the low and moderate hyperopia groups. CONCLUSIONS: Hyperopic LASIK using the WaveLight ALLEGRETTO WAVE excimer laser appears to be safe and effective in the correction of low, moderate, and high hyperopia and hyperopic astigmatism.

Journal ArticleDOI
TL;DR: The risk of retinal detachment in eyes implanted with phakic lenses for the correction of high myopia is higher in eyes with axial length >30.24 mm.
Abstract: PURPOSE To analyze the risk of retinal detachment in highly myopic patients who underwent implantation of phakic intraocular lenses (PIOLs). METHODS In a retrospective, non-comparative, interventional case series, the occurrence of retinal detachment was analyzed in 522 consecutive highly myopic eyes (323 patients) that underwent PIOL implantation. Treatment and results were reviewed. Parameters evaluated were best corrected visual acuity before and after retinal detachment surgery and time between refractive surgery and retinal detachment. RESULTS Fifteen (2.87%) eyes presented with retinal detachment after PIOL implantation, with a mean time between surgery and detachment of 24.4 +/- 24.4 months (range: 1 to 92 months). The risk of retinal detachment in patients with high myopia corrected by PIOL implantation was 0.57% at 3 months, 1.64% at 12 months, 2.73% at 36 months, and 4.06% at 92 to 145 months (Kaplan-Meier analysis). A comparative study between the group of patients with retinal detachment and the remaining patients without retinal detachment was performed. Differences were found in axial length (30.65 +/- 1.97 vs 29.51 +/- 2.02; P=.028, one factor-analysis of variance test). CONCLUSIONS The risk of retinal detachment in eyes implanted with phakic lenses for the correction of high myopia is higher in eyes with axial length >30.24 mm.