Showing papers on "Cataract surgery published in 1997"

Endothelin-like immunoreactivity in aqueous humor of patients with primary open-angle glaucoma and cataract.

Abstract: • Background: Experimental evidence suggests a role of endothelin-1 (ET) in the regulation of intraocular pressure (IOP). • Method: Therefore, inpatients undergoing cataract surgery, ET-like immunoreactivity (STIR) was measured by radioimmunoassay in pooled samples of aqueous humor of eyes with primary open-angle glaucoma (POAG) and normotensive eyes with cataract only. • Results: ETIR was significantly (P < 0.05) higher in patients with cataract and POAG (20.5 ± 1.8 pg/ml,n = 12; preoperative IOP 21.4 ± I.1 mmHg,n = 33) than in patients with cataract only (15.8 ± 1.6 pg/m1,n = 15; preoperative IOP 16.0 ± 0.6 mmHg,n = 77). • Conclusion: This finding may indicate a role of ET in POAG or ocular antihypertensive treatment, and its relevance should be further investigated.

Prevalence of lens opacities in the Barbados Eye Study

Abstract: Objective: To present population-based data on type and extent of age-related lens opacities in the predominantly black population of the Barbados Eye Study. Design: Prevalence study. Setting and Participants: The Barbados Eye Study included 4709 participants (84% of those eligible), who were identified from a random sample of Barbadian-born citizens aged 40 to 84 years. Data Collection: Lens gradings at the slit lamp, obtained with the use of the Lens Opacities Classification System II. Main Outcome Measure: Prevalence of posterior subcapsular, nuclear, and cortical opacities (defined as a grade ≥2 in either eye), as well as prevalence of any lens changes (including history of previous cataract surgery and/or cataract too advanced to grade). Results: Overall, 41% of the Barbados Eye Study population had any lens changes, including 3% with aphakia or an intraocular lens. Among the population of African descent, cortical opacities (34%) were most prevalent, followed by nuclear (19%) and posterior subcapsular (4%) opacities. Prevalence of all opacity types increased with age (P Conclusions: The Barbados Eye Study provides the first prevalence data on different types of lens opacities in a large, predominantly black population. Whereas nuclear opacities are most common in white populations, cortical opacities were the most frequent type in the Barbados Eye Study, a finding of possible etiologic relevance. Other results highlight a higher frequency of opacities in women than men and a high prevalence of visual acuity loss in affected eyes.

Unpreserved lidocaine to control discomfort during cataract surgery using topical anesthesia

Abstract: Purpose: To determine whether intraoperative unpreserved lidocaine further decreases discomfort or pain during sutureless small incision cataract surgery and intraocular lens (IOL) implantation under topical anesthesia. Setting: Outpatient ambulatory surgical center. Methods: In this prospective controlled study, comparable eligible patients were randomized to receive 0.1 cc unpreserved lidocaine 1 % or 0.1 cc balanced salt solution (BSS®) (control group) in double-masked fashion. Study drugs were injected intracamerally 1 minute before phacoemulsification. A predefined uniform pain/discomfort scale was used for assessment during phacoemulsification and IOL insertion. A secondary study using a 0.5 cc dose was also performed. Results: Twenty-six percent in the control group and 9% in the lidocaine group had discomfort pain scores of 2 or more; 10% in the BSS group felt increased pressure or pain during phacoemulsification. In the lidocaine group, discomfort was felt mainly during IOL insertion, possibly as a result of wound manipulation. During phacoemulsification, no patient in the lidocaine group reported pain; 2% felt increased pressure during phacoemulsification. A dose increase to 0.5 cc reduced any intraocular sensation to 3% in the lidocaine group. No patient in either group had significant cell loss or adverse events. Conclusion: Intraoperative lidocaine is safe and effective in controlling intraoperative discomfort.

Retrospective comparison of techniques to prevent secondary cataract formation after posterior chamber intraocular lens implantation in infants and children

Abstract: Purpose: To determine the effect of various methods of managing the posterior capsule and anterior vitreous on the rate of posterior capsule opacification in pediatric eyes implanted with posterior chamber intraocular lenses (PC IOLs). Setting: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. Methods: We reviewed the charts of 20 eyes of 15 children (aged 1.5 to 2 years) who had primary cataract surgery with PC IOL implantation during the past 5 years. The posterior capsule and anterior vitreous were managed in a variety of ways: In 5 eyes, the posterior capsule was left intact; in 15 eyes, a posterior continuous curvilinear capsulorhexis (PCCC) was performed-6 with and 9 without anterior vitrectomy; in 8 eyes, posterior optic capture was performed-3 with and 5 without vitrectomy. The follow-up ranged from 1 to 4.5 years (mean 2 years). Results: Visually significant secondary cataract developed in the five eyes with intact posterior capsules and in the four eyes that had PCCC without vitrectomy and without posterior optic capture (i.e., the optic was left in the capsular bag). The optical axis remained clear in the six eyes that had PC IOL implantation with vitrectomy (with or without posterior optic capture). Initially, all eyes that had optic capture without vitrectomy also remained clear, but after 6 months, four of five developed opacification. Conclusion: In this series, PCCC with anterior vitrectomy was the only effective method of preventing or delaying secondary cataract formation in infants and children.

Thapsigargin-coated intraocular lenses inhibit human lens cell growth.

Abstract: Cataract is responsible for rendering several million people blind throughout the world1 and is also by far the most common cause of low visual acuity. Although cataract surgery is common, routine and effective, posterior capsule opacification (PCO) occurs in 30–50% of patients following modern cataract surgery. This condition arises from stimulated ceil growth within the capsular bag after surgery2. The resulting decline in visual acuity requires expensive laser treatment2, and PCO therefore prevents modern cataract surgery from being carried out routinely in underdeveloped countries. The present study, using a human lens capsular bag culture system3, has confirmed that cells from a wide age range of donors proliferate in the absence of added serum protein4 and explains why PCO is such a common problem even in aged patients. This study also provides one possible solution for PCO by using polymethylmethacrylate (PMMA) implanted intraocular lenses as a drug delivery system. PMMA lenses coated with thapsigargin, a hydrophobic inhibitor of endoplasmic reticulum (ER) (Ca2+)-ATPase5, greatly reduced cell growth in the capsular bag at relatively low coating concentrations (200 μM) but, more significantly, induced total cell death of the residual anterior epithelial cells at higher concentrations (>2 μM).

Measurements of Vision Function and Quality of Life in Patients With Cataracts in Southern India Report of Instrument Development

Abstract: Objective: To develop and validate vision function (VF) and quality of life (QOL) instruments in patients with cataracts in the context of large volume surgery in a developing country. Materials and Methods: The instruments were developed using a consensus approach. One hundred patients who were undergoing cataract surgery at Aravind Eye Hospital, Madurai, India, were interviewed preoperatively and 3 and 12 months postoperatively. Standard clinical procedures were followed, including measurement of visual acuity. Between-interviewer reproducibility was measured by repeated administration of the preoperative questionnaire. Withininterviewer reproducibility was measured preoperatively in a separate study of 50 patients. Results: Preoperative scores from the VF and QOL instruments were significantly associated with visual acuity (r=0.4). Internal reliability (Cronbach α) was greater than.9. Both instruments showed large changes after surgery, with effect sizes of 3 or greater for most VF scales (range, 1.8-3.7) and 1 or greater for QOL scales (range, 1.0-2.2). Changes in visual acuity after surgery were correlated with changes in the VF (r=0.44) and QOL (r=0.41) scale scores. Betweeninterviewer reproducibility was acceptable (total VF scale, Spearmanr=0.7; total QOL scale,r=0.74). The κ values were lower for within-interviewer reproducibility. Conclusions: The study provided strong evidence for the validity, reproducibility, and responsiveness of the instruments, and for the feasibility of using them in the setting of a large volume of cataract surgery in a developing country.

Management of zonular dialysis in phacoemulsification and IOL implantation using the capsular tension ring.

Abstract: * BACKGROUND AND OBJECTIVES: Cataract surgery with zonular dialysis remains a challenge for surgeons performing phacoemulsification and posterior chamber intraocular lens implantation. In this article, the authors report the results of cataract surgery with zonular dialysis that was managed with the capsular tension ring. PATIENTS AND METHODS: Of the 14 cataract surgery cases with loose or broken zonules managed with capsular tension rings that were retrospectively reviewed, 5 selected cases are presented in this article. *RESULTS: The authors found that the capsular tension ring helps to avoid capsular collapse and vitreous presentation during surgery and maintains the circular contour of the capsular bag, allowing the intraocular lens to easily be placed into the bag. There was no observable decentration of the intraocular lens after surgery. * CONCLUSION: The capsular tension ring may provide an alternative means to manage zonular dialysis during phacoemulsification and posterior chamber intraocular lens implantation.

Catquest questionnaire for use in cataract surgery care: description, validity, and reliability.

Abstract: Purpose: To describe and evaluate the Catquest self-assessment questionnaire for cataract patients. Setting: Thirty-five Swedish departments of ophthalmology. Methods: The Catquest is designed to be used by cataract surgeons for continuous quality control regarding appropriateness and outcome of surgery. It is administered before and after cataract surgery. The questionnaire focuses on visual disabilities in daily life, activity level, cataract symptoms, and degree of independence. The results are interpreted using a benefit matrix that credits not only a decrease in visual disabilities and cataract symptoms but also an improvement or a maintenance of a preoperative activity level. The questionnaire was used by consecutive patients having surgery during March 1995 at the participating surgical units. Results: A full range of responses was given to all questions. A strong relationship was found between patients' responses to questions about visual disabilities in daily life and their general opinion about vision ( P P P Conclusion: The Catquest had high validity and reliability when used as a diseasespecific instrument testing visual disabilities in patients having cataract extraction.

Risk of endophthalmitis after cataract extraction: results from the International Cataract Surgery Outcomes study

Abstract: Aim—To estimate risk of infectious endophthalmitis after cataract extraction in Denmark and to compare results with the risk of this complication in the USA Methods—In the national Danish administrative hospital register, 19 426 patients were identified who underwent first eye cataract surgery from 1985 to 1987 and who were 50 years of age or older. Of these, 61 patients had postoperative endophthalmitis. Results—A 12 month cumulative risk of rehospitalisation for endophthalmitis was estimated at 0.18% (95% CI 0.09‐0.26) after extracapsular cataract extraction with lens implant. Advanced age, male sex,intracapsular cataract extraction,and anterior vitrectomy were all associated independently with an increased risk of postoperative endophthalmitis. When restricting the sample to patients aged 65 years or older, in order to allow comparisons to be made with the US National Study of Cataract Outcomes, a 12 month risk of 0.17% (95% CI 0.08‐0.25) was estimated. The previously reported US risk of 0.12% is included in the confidence interval of the risk estimated in the Danish sample. Conclusion‐Despite considerable diVerences in the healthcare systems, no statistically significant diVerence in outcome of surgery as measured by risk of endophthalmitis was shown between Denmark and the USA. (Br J Ophthalmol 1997;81:102‐106)

Posterior continuous curvilinear capsulorhexis and optic capture of the intraocular lens to prevent secondary opacification in pediatric cataract surgery

Abstract: Purpose: To evaluate the safety and efficacy of posterior continuous curvilinear capsulorhexis with optic capture in preventing secondary opacification of the visual axis in pediatric eyes having cataract surgery and intraocular lens (IOL) implantation. Setting: Gimbel Eye Centre, Calgary, Alberta, Canada. Method: Posterior continuous curvilinear capsulorhexis with optic capture of the IOL was performed in 18 of 19 consecutive pediatric cataract patients (ages 2 1/2 to 12 years). Heparin-coated IOLs with 6 degree angulation of the haptics were implanted in all eyes. Only eyes with a minimum of 18 months follow-up (n = 16) were analyzed. Results: Mean follow-up in the 16 eyes was 35.5 months ± 9.45 (SD), ranging from 19 to 49 months. To date, the visual axis has remained clear in all eyes. No anterior vitrectomy was purposefully performed in any eye. Conclusion: Posterior continuous curvilinear capsulorhexis with optic capture of the heparin-coated IOL appeared to successfully prevent secondary opacification of the visual axis in pediatric cataract cases.

Visual impairment in nursing home residents: the Blue Mountains Eye Study.

Abstract: Objectives To assess the prevalence and causes of visual impairment, and the proportion of treatable eye conditions, among nursing home residents. Design and setting The Blue Mountains Eye Study is a population-based survey of vision and common eye diseases in people aged 50 or older in two postcode areas west of Sydney. Nursing home examinations were conducted during 1993. Participants Three representative nursing homes were selected from the nine in the study area. There were 128 residents aged 50 or older (64% females), representing 21% of all eligible nursing home residents in the two postcode areas. Main outcome measure Blindness or visual impairment in one or both eyes. Results Eye examinations were refused by five nursing home residents, and dementia precluded eye examination in 34 (28%) of the remainder. We found significantly higher prevalences (fivefold increase) of bilateral (11%) and unilateral (21%) blindness in nursing home residents compared with local community residents (bilateral, 0.5%; unilateral, 2%). In seven of the 10 blind nursing home residents, the blindness was potentially reversible (advanced cataract); late age-related macular degeneration (AMD) was the second most frequent cause of blindness, affecting one or both eyes of 12% of residents. Open-angle glaucoma affected 10% and advanced cataract 11%; a history of past cataract surgery was obtained in 14%. Conclusions These data confirm earlier reports of a substantial number of treatable eye diseases, particularly advanced cataract, in nursing home residents, and indicate a need for increased surveillance of these communities. The high rate of visual impairment and blindness, compared with similar age groups in the local community, suggests that visual disability may contribute to nursing home placement.

Anterior chamber contamination during cataract surgery with intraocular lens implantation.

Abstract: Purpose: To measure anterior chamber bacterial and fungal contamination at the beginning and end of cataract surgery with intraocular lens (IOL) implantation in a large series of patients and to determine the influence of preoperative treatment and operative technique on contamination. Setting: Department of Ophthalmology, County Hospital of Salzburg, Austria. Methods: This prospective study comprised 700 consecutive patients having planned cataract extraction (511 phacoemulsification, 189 extracapsular cataract extraction [ECCE]). Thirty-four patients required an anterior vitrectomy; 8 myopic patients did not receive an IOL. A preoperative smear and two intraoperative (at the beginning and end of surgery) anterior chamber aspirates were obtained from each patient. Postoperative smears were obtained at discharge. Three preoperative treatments were evaluated: no lacrimal system irrigation, no topical antibiotic (n = 282); lacrimal system irrigation with balanced saline solution, no topical antibiotic (n = 243); lacrimal system irrigation, antibiotic (neomycin) eyedrops (n = 175). All patients received topical indomethacin twice a day preoperatively. Results: Preoperative conjunctival smears showed bacterial growth in 76.6% of eyes, with coagulase-negative staphylococci (75%) the most common bacteria. Anterior chamber aspirates were culture positive in 14.1 % at the beginning and in 13.7% at the end of surgery, with coagulase-negative staphylococci and corynebacteria the most common. Contamination rates of conjunctival smears taken at discharge were significantly lower (35%) than those taken preoperatively. There was no statistically significantly higher risk of anterior chamber contamination in eyes having ECCE than in those having phacoemulsification. Preoperative treatment did not statistically significantly influence intraoperative aqueous humor contamination rates. There were no cases of acute postoperative endophthalmitis. Conclusion: Bacteria entered the anterior chamber during cataract extraction and remained there at the end of surgery in a significant percentage of patients. Surgical technique, preoperative antibiotics, and preoperative lacrimal system irrigation had no statistically significant effect on contamination.

Adjustable intraocular lens implant with magnetic adjustment facilities

Abstract: An adjustable ocular insert to be implanted during refractive cataract surgery and clear (human) crystalline lens refractive surgery and adjusted post-surgically. The implant comprises relatively soft but compressible and resilient base annulus designed to fit in the lens capsule and keep the lens capsule open. Alternatively the annulus may be placed in the anterior or posterior chamber. The annulus includes a pair of opposed haptics for secure positioning within the appropriate chamber. A rotatable annular lens member having external threads is threadedly engaged in the annulus. The lens member is rotated to move the lens forward or backward so to adjust and fine tune the refractive power and focusing for hyperopia, myopia and astigmatism. The intraocular implant has a power range of approximately +3 0 -3 diopters. The lens member can be removed from the base annulus and lifted out of the eye so that the lens can be changed, adjusted, modified or entirely removed with new assembly placed for the patient's changing visual needs and lifestyle with less stress on the base annulus and on the rotatable lens member. Magnetic elements may be operatively associated with the lens member, and responsive to a magnetic form of tool useful for providing a turning of the lens and a readjustment in its focusing power.

Pseudoexfoliation syndrome and secondary cataract

Abstract: AIM/BACKGROUND The pseudoexfoliation (PEX) syndrome is frequently associated with impairment of the blood-aqueous barrier. This study analysed if this might stimulate secondary cataract following cataract extraction. METHODS This historical cohort study included 197 eyes of 197 patients (99 with and 98 without PEX) that underwent extracapsular cataract extraction with posterior chamber lens implantation (PMMA optic) between 1985 and 1991. Secondary cataract was defined as opacification of the axial posterior capsule and decrease of visual acuity by two or more lines. Mean follow up was 23.8 months. For statistical analysis, the Kaplan–Meier method and multivariate Cox regression analysis were used. RESULTS Secondary cataract was observed within 24 months in 35% (SD 7%) of all eyes, and was significantly more frequent in eyes with PEX (45 (11)%) than in eyes without PEX (24 (9)%, p CONCLUSION The higher frequency of secondary cataract could be considered as another potential complication of cataract surgery in eyes with PEX.

Knowledge and beliefs about common eye diseases.

Abstract: Purpose: To ascertain the level of knowledge of common causes of blindness in an adult Australian population and to relate this to use of eye care services. Methods: A population-based study of common eye diseases in an urban population aged 49 years or older was conducted. The questions were concerned with the awareness and knowledge of and the ability to describe three common eye diseases, namely cataract, glaucoma and agerelated macular degeneration (AMD). Results: Awareness of cataract (98%) and glaucoma (93%) were high in this population, but awareness of AMD was low (20%). Among people who were aware of the target eye disease, only 29% showed some knowledge of glaucoma, 26% showed some knowledge of AMD and 20% showed some knowledge of cataract; this was also low in people who had previous eye treatment, such as cataract surgery. Knowledge was related to education level, occupational prestige and knowledge of other eye diseases. After excluding people with a previous eye disease diagnosis, those people who were aware and had some knowledge of eye disease accessed eyecare services more frequently. Conclusions: Knowledge of common eye diseases is generally lacking. Age-related macular degeneration is the leading cause of blindness in Australia, yet only 20% of the present study population had heard of it. As there are often no early symptoms for glaucoma, community awareness of this disease and the need for screening of people at risk may allow timely diagnosis and more effective therapy before advanced visual field loss has occurred. An informed public is more likely to present earlier with visual symptoms before irreversible visual loss has occurred and is more likely to comply better with recommended therapy.

Surgery for Cataracts

Abstract: The advent of phacoemulsification has substantially improved the success rate of cataract surgery in dogs, whereas the development of artificial lens implantation has equally improved postoperative visual acuity. In this chapter information pertaining to the etiology, diagnosis, and management of canine cataracts is provided for the general practitioner. More detailed information on phacoemulsification and artificial lens implantation is provided for residents in training or practicing ophthalmologists that may be converting from extracapsular extraction.

Corneal endothelial function after extracapsular cataract extraction and phacoemulsification

Abstract: Purpose: To compare the morphology and function of the corneal endothelium in the early postoperative period after extracapsular cataract extraction (ECCE) and phacoemulsification. Setting: University Eye Clinic of Trieste, Italy. Methods: In this prospective, randomized study of patients scheduled for cataract surgery, 40 patients were divided into two groups of 20 patients each. Group 1 had ECCE and Group 2, phacoemulsification; both had capsular bag intraocular lens (IOL) implantation. Preoperatively and 7 and 30 days postoperatively, a complete ophthalmological examination, endothelial specular microscopy, ultrasonic pachymetry, and anterior segment fluorophotometry were done. Visual acuity, endothelial cell density, cell size variation coefficient, corneal thickness, endothelial permeability coefficient, and endothelial pump function were studied. Results: Visual acuity was better 7 days after phacoemulsification than after ECCE, but no differences were observed after 30 days. No significant differences in postoperative loss of endothelial cells were found between the two groups. Coefficient of variation in size, corneal thickness, and endothelial permeability significantly increased in both groups 7 days postoperatively, but only in the ECCE group 30 days postoperatively; the differences between the two groups were statistically significant. Endothelial pump function significantly increased after 7 days in only the phacoemulsification group. Conclusions: Functional endothelial failure occurred in the early period after ECCE. Phacoemulsification seemed to minimize postoperative functional damage to the endothelium.

Willingness to pay to shorten waiting time for cataract surgery

Abstract: We interviewed persons who had recently been placed on a public waiting list for cataract surgery in Manitoba, Canada; Barcelona, Spain; and Denmark. The majority of the respondents were ...

Topical 0.5% ketorolac vs 0.03% flurbiprofen for inhibition of miosis during cataract surgery.

Abstract: Objective: To compare the effects of topical 0.5% ketorolac tromethamine ophthalmic solution (Acular, Allergen Pharmaceuticals, Irvine, Calif) with topical 0.03% flurbiprofen sodium ophthalmic solution (Ocufen, Allergen Pharmaceuticals) on the inhibition of surgically induced miosis during phacoemulsification cataract surgery. Design: One hundred eighteen patients were prospectively randomized to receive 0.5% topical ketorolac or 0.03% topical flurbiprofen at 3 preoperative intervals. The flurbiprofen-treated group served as the control group. The surgeon was masked as to patient selection. Horizontal pupillary diameter measurements were obtained at the start of surgery, just before phacoemulsification, before lens implantation, and after lens implantation. Results: Mean horizontal pupillary diameter measurements for both medications were similar at the start of surgery. However, a consistent trend of larger pupillary diameter was seen in all subsequent surgical intervals in the ketorolac-treated group. Changes from baseline measurements also indicated a more significant inhibition of miosis at all subsequent intervals, and a more stable mydriasis throughout the procedure in the ketorolac-treated group. Conclusions: Topical ketorolac is an effective inhibitor of miosis during phacoemulsification cataract surgery, and provides a more stable mydriatic effect throughout the surgical procedure.

Anterior chamber irrigation with unpreserved lidocaine 1% for anesthesia during cataract surgery.

Abstract: Purpose: To assess the effectiveness of using anterior chamber irrigation of unpreserved lidocaine 1 % as anesthesia during cataract surgery. Setting: Private group ophthalmology practice. Methods: This study prospectively evaluated 1000 of 1012 consecutive eyes having temporal corneal incision cataract surgery to determine whether anterior chamber lidocaine provides adequate anesthesia for cataract surgery. Twelve eyes were excluded because the patients had preoperative sedation. Surgery on the remaining 1000 eyes was performed by one surgeon without patients receiving preoperative or intraoperative sedation or other medications other than the local anesthetic and dilating agents. Each received one drop of topical proparacaine before entering the operating room. After an initial corneal stab incision was made, 0.25 to 0.50 cc of unpreserved lidocaine 1% was irrigated into the anterior chamber. Results: One patient was so uncomfortable from the microscope that he required supplemental retrobulbar anesthesia. A second patient was extremely uncomfortable during the case but did not require supplemental anesthesia. Two patients received additional dosages of anesthetic because of discomfort late in the operation. The remaining 996 patients were comfortable and pain-free during the operation with a single dose of the anesthetic. Conclusion: Anterior chamber irrigation with unpreserved lidocaine 1% was an effective method for anesthetizing an eye for temporal corneal incision cataract surgery.

Myopic shift after cataract removal in childhood.

Abstract: Background: Children who have had cataract removal tend to have decreasing hyperopia (myopic shift) as they grow older. We wondered if the rate of myopic shift could be determined by age at surgery, cataract type, glaucoma, or other factors. Methods: We studied 156 aphakic eyes of children who had cataract surgery before age 10 and documented refractions for more than 3 years. Refraction was corrected with contact lenses and spectacles; glaucoma was managed with medicine and surgery. Stepwise multiple regression was used to analyze differences in the rate of myopic shift between subgroups. Results: The average refraction tended to follow a logarithmic decline with age (P<0.01, R 2 =0.97). The average rate of myopic shift (the slope of spectacle plane refraction vs log of age, where age is in years and log is base 10) was -5.5, with a standard deviation of 3.8. Age at surgery had a small but statistically significant effect on the rate (P<0.01, R 2 =0.04). No other studied factor reached statistical significance. However, among the 86 eyes with cataract removal after age 6 months, age at surgery was not as significant (P=0.21), and unilateral cataract eyes tended to have a greater rate than bilateral cataract eyes (-7.7 vs -5.7; P=0.05, R 2 =0.05). Conclusions: Aphakic refraction tends to follow a logarithmic decline with age. The rate of myopic shift is determined partly by age at surgery and whether the cataract was unilateral or bilateral, although the effects are small. A wide variation in the rate of myopic shift exists. The following factors made little difference in the rate: cataract type, glaucoma, sex, side, and best corrected visual acuity.

Corneal versus scleral tunnel incision in cataract surgery: A randomized study

Abstract: Purpose: To compare the induced regular and irregular astigmatism after scleral and corneal tunnel incision. Setting: University hospital outpatient cataract clinic. Methods: One hundred phacoemulsification patients with less than 1.0 diopter (D) of preoperative astigmatism were randomly assigned to have a clear corneal incision (50 patients) or a scleral tunnel incision (50 patients). All incisions were 3.5 to 4.0 mm wide and were made in the steepest axis of the corneal astigmatism. The surgically induced astigmatism was analyzed by vector analysis from keratometric data, as well as by Fourier harmonic series analysis of the topographic data. Results: One day after surgery, the surgically induced astigmatism (vector analysis, keratometry) was 1.41 D ± 0.66 (SD) and 0.55 ± 0.31 D in the corneal incision group and the scleral incision group, respectively (P < .01). Six months after surgery, the induced astigmatism was 0.72 ± 0.35 D and 0.36 ± 0.21 D in the two groups, respectively (P < .01). The corneal topography data confirmed the regular astigmatism changes found by conventional keratometry. However, in addition, Fourier harmonic series analysis of the topography data showed significantly more irregular induced astigmatism with the corneal approach than with the scleral approach. Conclusion: The clear corneal incision induces significantly more regular as well as irregular astigmatism than the scleral tunnel incision.