Showing papers by "Gottfried O. H. Naumann published in 2003"

Influence of Photodynamic Therapy on Expression of Vascular Endothelial Growth Factor (VEGF), VEGF Receptor 3, and Pigment Epithelium–Derived Factor

Abstract: Purpose To evaluate the impact of photodynamic therapy (PDT) on expression and distribution of vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR)-3, and pigment epithelium-derived factor (PEDF). Methods Eyes of patients scheduled for enucleation due to untreatable malignancy served as study eyes (n = 4), age-matched donor eyes were used as the control (n = 4). PDT using verteporfin with the recommended standard parameters was applied to intact areas of the perimacular region. Lesions were classified by ophthalmoscopy, fluorescein angiography (FA), and indocyanine green angiography (ICGA), as well as light and electron microscopic (LM/EM) histology. Immunolabeling using specific antibodies against VEGF, VEGFR-3, and PEDF was performed in PDT-treated areas, untreated collateral areas in study eyes, and untreated areas of control eyes. Specimens were fixed in 4% paraformaldehyde and 1% glutaraldehyde and embedded in paraffin. Four-micrometer-thick sections were stained using the peroxidase-labeled streptavidin-biotin method. Results All PDT-treated areas demonstrated characteristic choroidal hypofluorescence by FA and ICGA. LM/EM histology revealed selective damage of choriocapillary endothelial cells. VEGF was expressed in the endothelial layer of choriocapillaries and focally within larger choroidal vessels in treated areas, but not in untreated areas. Sites with positive VEGF labeling also demonstrated upregulation of VEGFR-3. PEDF expression was localized to retinas in all eyes; however, PEDF staining of choroidal endothelial cells was specific for treated areas of study eyes. Conclusions PDT using verteporfin induces a reproducible angiogenic response in elderly human eyes. VEGF, VEGFR-3, and PEDF expression is enhanced after PDT. Choroidal endothelial cells appear to be the primary site of angiogenic stimulation.

Matrix metalloproteinases and their inhibitors in aqueous humor of patients with pseudoexfoliation syndrome/glaucoma and primary open-angle glaucoma

Abstract: Purpose To determine the presence, activity, and quantitative differences of matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs) in aqueous humor and serum samples of patients with pseudoexfoliation (PEX) syndrome, PEX glaucoma (PEXG), primary open-angle glaucoma (POAG), and cataract. Methods Aqueous humor and serum samples were collected from 100 patients with PEX syndrome, PEX glaucoma (PEXG), POAG, and cataract, respectively. Levels of MMP-1, -2, -3, -7, -9, and -12 and TIMP-1 and -2 were determined by zymography, Western blot analysis, and specific immunoassays. Activity assay kits were used to quantitate levels of endogenously activated MMP-2 and -9. Results MMP-2, -3, -7, -9, and -12 and TIMP-1 and -2 were identified in human aqueous humor samples from all groups of patients with a six to sevenfold molar excess of TIMPs over MMPs. Whereas serum samples showed no significant differences, total MMP-2 and -3 and TIMP-1 and -2 were detected at significantly higher concentrations in aqueous samples from PEX eyes with and without glaucoma compared with cataractous eyes. MMP-2 and -3 and TIMP-1 were also detected in higher, but not significantly different, amounts in aqueous samples of POAG eyes. However, levels of endogenously activated MMP-2 were significantly decreased in both PEX and POAG samples. The ratio of MMP-2 to its principal inhibitor TIMP-2 was balanced in cataract samples, but was decreased in samples from patients with PEXG, resulting in an excess of TIMP-2 over MMP-2. Conclusions The findings suggest that complex changes in the local MMP-TIMP balance and reduced MMP activity in aqueous humor may promote the abnormal matrix accumulation characteristic of PEX syndrome and may be causally involved in the pathogenesis of both PEX glaucoma and POAG.

Penetrating keratoplasty for endothelial decompensation in eyes with buphthalmos.

Abstract: Purpose To evaluate the prognosis and complications of penetrating keratoplasty (PKP) for corneal decompensation in eyes with buphthalmos and to analyze the risk factors for graft failure. Patients and methods Clinical records of 13 adult and three pediatric patients who underwent PKP for endothelial decompensation with a previous diagnosis of congenital glaucoma of a total of 3,663 corneal transplantations performed in our department between January 1987 and December 2001 were reviewed retrospectively. During the study period, a total of 33 PKPs was performed in 20 eyes with buphthalmos. The median age of the patients at the time of PKP was 39 years (range, 3 to 72). All patients had a history of intraocular surgery, including multiple glaucoma surgeries, cataract extraction, and PKP. The impact of pre-, intra-, and postoperative factors on graft failure and duration of graft clarity was analyzed. Results Fifty-five percent (11/20) of the eyes received only one graft, 25% (5/20) received two, and 20% (4/20) received three grafts. During a mean follow-up of 87.2 months (range, 4.5-72), graft failure occurred in 18 of 33 grafts (54%). Seven (7/18, 39%) had immunologic graft rejection, and 11 (11/18, 61%) had nonimmunologic graft failure. At the end of the follow-up, 75% (15/20) of the eyes had clear grafts. Duration of graft clarity was found to be significantly shorter in regrafts compared with that of primary grafts (27.0 +/- 27.7 versus 56.4 +/- 41.0 months, p= 0.02). After PKP, intraocular pressure (IOP) was uncontrolled in 12 (12/33, 36%) grafts. Nine of 20 eyes (45%) required an average of 3.2 cyclodestructive procedures per eye for pharmacologically resistant elevated IOP. The final postoperative vision improved in 70% (14/20) of the eyes and the best visual acuity postoperatively (75% > or =20/400) was significantly better than the preoperative visual acuity (25% > or =20/400, p= 0.0001). Conclusions Endothelial decompensation due to congenital glaucoma is a very rare indication for PKP. The incidence of graft failure is high, and nonimmunologic reasons are the leading causes of graft failure in this high-risk population. Visual acuity can be significantly improved but is usually still very limited by advanced glaucomatous optic nerve damage and amblyopia. Efficient control of IOP before and after PKP is mandatory in eyes with buphthalmos to avoid graft failure and progress of glaucomatous optic nerve atrophy.

Impact of preoperative corneal curvature on the outcome of penetrating keratoplasty in keratoconus.

Abstract: Purpose. To assess the impact of the patient's preoperative corneal curvature on the refractive outcome after penetrating keratoplasty (PK) in keratoconus before and after suture removal. Patients and Methods. In this retrospective cross-sectional clinical study, 236 keratoconus patients (mean age 37 ′ 11 years) were divided into four groups based on their preoperative keratometric (K-) readings: group 1, <50 diopters (D) (n = 24); group 2, <60 D (n = 52);group 3, ≥ 60D(n = 101); group 4, irregular corneal shape with unmeasurable K-reading (n = 59). An 8.0/8.1-mm central round PK was performed using 193 nm Meditec excimer laser trephination along metal masks with eight "orientation teeth/notches." A 16-bite double running cross-stitch suture was applied in all cases. Postoperative examinations were performed before removal of the first suture (ie, 12 months) and after removal of the second suture (ie, 18 months). The outcome measures included central power (C-power), keratometric astigmatism (AST), surface regularity index (SRI), surface asymmetry index (SAI), spherical equivalent (SEQ), refractive cylinder (Cyl), and best corrected visual acuity (BCVA). In addition, the regularity of Zeiss keratometry mires was classified semiquantitatively (0, regular; 1, mildly irregular; 2, moderately irregular; 3, unmeasurable). Results. Before/after suture removal, median C-power was 43.4/43.3 D; AST was 3.0/3.0 D; SAI was 0.6/0.6; SRI was 0.9/0.9; Cyl was 2.5/2.5 D; BCVA was 0.7/0.7. After suture removal, the percentage of regular keratometry mires increased from 37% to 61%. Comparisons among the four groups revealed no significant differences for any parameters tested either before or after suture removal. Conclusions. With laser trephination and a double running suture, the refractive and visual outcome of PK for keratoconus seems to be independent on the patient's preoperative corneal curvature or irregularity. Suture removal did not effect an increase of corneal astigmatism but did increase the proportion of regular keratometry mires. Thus, our policy of not performing PK in keratoconus eyes before the patient becomes contact lens intolerant is well supported.

Penetrating keratoplasty for iatrogenic keratoconus after repeat myopic laser in situ keratomileusis: histologic findings and literature review.

Abstract: We report a patient with a sufficiently thick cornea (593 microm) and no topographic signs of keratoconus preoperatively who developed iatrogenic keratoconus 2 months after repeat laser in situ keratomileusis (-4.00 -1.00 x 20) performed 5 months after the primary procedure (-10.50 -1.00 x 55). After penetrating keratoplasty, macrophotography showed severe multidirectional "macrostriae" of the stromal bed. On histologic evaluation, excessive thinning of the residual stromal bed to a minimum of 75 microm in the valleys and a maximum of 200 microm at the peaks of the macrostriae were documented. The flap thickness was 225 microm in the center. The thicker-than-intended flap (160 microm) is thought to be the cause of the severe complication of the LASIK procedure.

Katarakt und Keratoplastik: simultane oder sequenzielle Operation?

Abstract: Background and purpose Since the introduction of the triple procedure (simultaneous penetrating keratoplasty [PK], extracapsular cataract extraction [CE] and implantation of a posterior chamber intraocular lens [PCIOL]) in the mid-seventies, there is an ongoing discussion among corneal surgeons concerning the best approach for combined corneal disease and cataract. Methods Besides the classical triple procedure (1), two alternative microsurgical approaches are feasible: (2) CE + PCIOL prior to PK and (3) CE + PCIOL after PK. For the refractive results after TRIPLE some intraoperative details are crucial: Trephination of recipient and donor from the epithelial side without major oversize (Guided Trephine System or Nonmechanical Excimer Laser Trephination) should preserve the preoperative corneal curvature. Graft and the PCIOL placed in the bag after continuous curvilinear capsulorhexis should be centered along the optical axis. If possible, performing the capsulorhexis under controlled intraocular pressure conditions prior to trephination may help to minimise the risk of capsular ruptures. Results The major advantage of the TRIPLE is the faster visual rehabilitation and less efforts for the mostly elderly patients. However, two intraocular interventions with approach (2) and (3) bear an increased risk of infection and suprachoroidal haemorrhage. Approach (2) requires a cornea that is still transparent enough to perform cataract surgery, and the risk of intraocular pressure rise after PK seems to be increased. Approach (3) has the potential of a simultaneous reduction of astigmatism during CE (appropriate location of the incision, simultaneous refractive keratotomies or implantation of a toric PCIOL). Disadvantages may include the loss of graft endothelial cells and the theoretically increased risk of immunological allograft reactions. After TRIPLE, major deviations from target refraction have been reported. However, individual multiple regression analysis may help to minimise this problem with appropriate methods of trephination. Since suture removal after PK may result in major individual changes of the corneal curvature, IOL power calculation for approach (3) requires all sutures to be removed at the time of CE. However, even after complete suture removal the abnormal proportions between anterior and posterior curvatures and/or the irregular topographies after PK may be responsible for marked IOL power miscalculations in the individual case. Conclusions The postulated better refractive outcome and better uncorrected visual acuity after the sequential approach is opposed by a markedly delayed visual rehabilitation. For this reason, we consider the TRIPLE procedure including CE via open sky in general anesthesia as the method of choice for combined lens and corneal opacities. Because of the often rapidly progressive nuclear cataracts after PK, we recommend the simultaneous approach in elderly patients with Fuchs' dystrophy even with incipient lens opacities.

[Block excision of epithelial ingrowth after cataract surgery--report on 15 patients].

Abstract: BACKGROUND Cystic or diffuse epithelial ingrowth into the anterior chamber after cataract surgery is a rare complication It can lead to painful secondary glaucomas or in case of fistulation to persisting ocular hypotony or atrophy of the globe due to wrong or inadequate therapy PATIENTS AND METHODS The cause of epithelial ingrowth was a previous cataract surgery in 15 of 59 patients (25 %, Erlangen Block-Excision Registry for epithelial ingrowth) Eleven patients were females Mean age was 65 +/- 13 years RESULTS Ten patients underwent block excision of epithelium, adjacent iris, ciliary body, sclera or cornea due to epithelial ingrowth following intracapsular cataract extraction between 1980 and 1987 and five patients since 1987 because of epithelial ingrowth following extracapsular cataract extraction (4 with and 1 without intraocular lens implantation); all primary cataract surgeries had been performed in external hospitals We found a diffuse invasion in 3 eyes (all following icCE) and a cystic epithelial invasion in 12 eyes histologically Mean time interval between cataract surgery and block excision was 7 +/- 8 years (range: 1 to 33 years) The excisional defect in the globes wall was covered using a tectonic corneoscleral graft (diameter: 80 +/- 18 mm) Postoperative astigmatism was 36 +/- 34 dpt Six eyes had postoperatively a visual acuity of 20/200 or better No recurrence of epithelial downgrowth was observed, nor was an enucleation needed CONCLUSION Surgical procedures with opening of the cyst (eg laser) are contraindicated and may lead to a transformation from cystic into diffuse epithelial invasion with potential blindness The therapy of first choice in eyes with cystic epithelial ingrowth and an extension less than five clock hours is the curative block-excision technique combined with tectonic corneoscleral graft Surgical results are excellent in order to regard a curative excision and the survival of the eye with acceptable achieved function in consideration of the difficult primary situation with intra- and postoperative complications due to previous cataract surgery

Therapie maligner Melanome der Konjunktiva bei primär erworbener Melanose (PEM) mit Mitomycin-C-0,02%-Augentropfen

Abstract: Wir berichten uber Erfahrungen bei der Therapie des malignen Melanoms der Konjunktiva bei primar erworbener Melanose mit Hilfe einer adjuvanten lokalen Mitomycin-C-Behandlung Zwischen 1998 und 2001 wurden13 Patienten mit lokaler Chemotherapie bei malignem Melanom (MM) der Konjunktiva behandelt Bei allen war das MM aus einer primar erworbenen Melanose (PEM) hervorgegangen Bei 7 Patienten lag ein Tumorstadium pT2 vor, bei 3 Stadium pT3 Bei 3 Patienten war das Lid in den malignen Prozess einbezogen (Stadium pT4) Die lokale Chemotherapie wurde nach inzisionaler Biopsie in 2 Zyklen zu je 14 Tagen mit 14-tagiger Pause durchgefuhrt Bei 4 Patienten wurde ein 3 Zyklus angeschlossen Eine Regression des Tumors wurde bei allen Patienten beobachtet Schwere okulare oder systemische Nebenwirkungen wurden nicht bemerkt Im Beobachtungszeitraum blieben 9 Patienten rezidivfrei, bei 3 kam es zu einem Rezidiv Bei diesen 3 Patienten war das Lid primar in den Tumorprozess eingeschlossen Die lokale Chemotherapie mit Mitomycin C stellt eine Bereicherung des therapeutischen Spektrums dar Wir halten die Kombination aus inzisionaler Biopsie mit chirurgischer Tumorvolumenreduktion und lokaler Mitomycin-C-Therapie fur eine gute Option, wenn das Tumorstadium pT3 nicht uberschritten wird

In-vivo-Messung der Autofluoreszenz in der parapapillären Atrophiezone bei Papillen mit und ohne glaukomatöse Optikusatrophie

Abstract: BACKGROUND To assess the level of autofluorescence (lipofuscin) of atrophic parapapillary zones in different stages of glaucomatous optic disc atrophy. METHODS Controlled cross-sectional prospective analysis of 79 consecutive eyes (15 normals as controls, 26 with ocular hypertension, 38 with primary open angle glaucoma). Eyes with retinal diseases or retinal pigment epithelial pathologies were excluded. The confocal scanning laser ophthalmoscope (HRA, Heidelberg Retina Angiograph) was used after lipofuscin excitation with argon blue laser (488 nm) to detect parapapillary autofluorescence in a spectrum above 500 nm. Size, extension of the parapapillary autofluorescent area and its mean distance to the optic nerve head were measured using the HRA standard software. Additional optic nerve head photographs taken with the 15 degrees Zeiss telecentric fundus camera (30 degrees camera with 2 x magnifier) were examined by two experienced ophthalmologists to determine the stage of glaucomatous optic disc atrophy (stages 0 to 4). RESULTS Very small autofluorescent areas were found in vital discs (optic nerve glaucoma stage 0) in the parapapillary atrophic area (0.08 +/- 0.12 mm (2)) in contrast to glaucomatous discs in stage 1 (0.24 +/- 0.26 mm (2)) and stages 2, 3 and 4 (0.59 +/- 1.29 mm (2), logistic regression analysis r = 0.71; P = 0.029). The circular extension of the autofluorescent area correlated borderlined with the stage of the glaucomatous disc atrophy (higher glaucoma stages: r = 0.82; P = 0.09). The autofluorescent area was larger in OHT than in controls (0.11 mm (2) vs. 0.04 mm (2), P < 0.03). The circular extension of the autofluorescent area was longer in OHT than in controls (0.5 mm vs. 1.15 mm, P < 0.04). CONCLUSIONS As a sign of pronounced lipofuscin accumulation in the parapapillary atrophic zone higher degrees of fundus autofluorescence can be detected in OHT and manifest primary open angle glaucoma in contrast to normals. The lipofuscin accumulation is correlated with the stage of progression of glaucoma and the stage of optic disc atrophy. The detection of active parapapillary autofluorescent areas especially in OHT may offer the ophthalmologist an important tool for early diagnosis.

Klassifikation der Erkrankungen der Augenoberfläche

Abstract: Der Begriff Augenoberflache betrachtet die anatomischen Strukturen von Lidrand, Bindehaut und Hornhaut zusammen mit dem tranensezernierenden System als eine funktionelle Einheit. Die unterschiedlichen Erkrankungen der Augenoberflache bieten wegen ihres teilweise ahnlichen Erscheinungsbildes mitunter differenzialdiagnostische Schwierigkeiten, die dann auch die Therapie erschweren. Die hier vorgeschlagene Klassifikation beruht auf den pathologischen und pathophysiologischen Charakteristika der Oberflachenerkrankungen und soll die Differenzialdiagnose erleichtern.

Nonmechanical Q-switched erbium:YAG laser trephination for penetrating keratoplasty: experimental study on human donor corneas.

Abstract: Objective To assess the alterations in human donor corneal tissue induced by Q-switched erbium (Er):YAG laser corneal trephination. Methods Thirty human corneoscleral donor buttons unsuitable for transplantation were placed in an artificial chamber on an automated rotation device. Corneas were trephined with a Q-switched Er:YAG laser (wavelength, 2.94 µm; pulse duration, 400 nanoseconds) along (donor and recipient) aluminum silicate(ceramic) open masks. A spot diameter of 0.65 mm, energy setting of 50 m J/pulse, and repetition rate of 5 Hz were used. Corneal thermal damage and cut regularity were quantitatively assessed in 24 corneas processed for light microscopy and by transmission and scanning electron microscopy. Results The stromal thermal damage was the highest (mean [SD], 8.0 [2.7] µm) at a 150-µm cut depth and decreased downward. Cut regularity was very good and did not significantly differ between donors and recipients. Scanning electron microscopy confirmed that the cuts were highly regular; transmission electron microscopy revealed 2 distinctive subzones within the stromal thermal damage zone. Conclusions Thermal damage induced by Q-switched Er:YAG nonmechanical corneal trephination was low, and the regularity of the cuts was very good. Clinical Relevance The Q-switched Er:YAG laser may have the potential to become an alternative to the excimer laser for nonmechanical penetrating keratoplasty.

Biomolecular Markers of Malignancy in Human Uveal Melanoma: The Role of the Cadherin-Catenin Complex and Gene Expression Profiling

Abstract: In recent years there has been a trend towards conservative management of uveal melanoma (UM), aimed at preserving the eye and vision. Despite improvements with this approach, recurrent tumour and metastatic disease still occur, and the management remains problematic. As a result of these limitations, there is interest in gaining a greater understanding of molecular changes associated with aggressive disease patterns in UM. This might result in new, more effective and less toxic therapies as well as provide prognostic information for defining subgroups of patients with a less favourable prognosis as potential candidates for adjuvant therapies. Accumulating evidence over the past decade suggests that disturbance in the cadherin-catenin adhesion complex is critical in the process leading to invasion and metastasis of many cancers. The recent advent of DNA micro-array technology now offers an unprecedented ability to study these molecules and others associated with malignant transformation. In this mini-review, the aspects of tumour progression in which cadherin-catenin may be involved are dealt with along with the potential application of DNA micro-array technology to the problem in UM.

Corneal shrinkage induced by nonmechanical Q-switched erbium:YAG laser trephination for penetrating keratoplasty in porcine eyes

Abstract: Purpose To assess the degree of corneal diameter shrinkage induced by Q-switched mid-infrared laser corneal trephination for penetrating keratoplasty in an experimental model.

Benign fibrous histiocytoma of the corneoscleral limbus: unique clinicopathologic features.

Abstract: Report of Cases. Case 1. A 26-yearold white woman was referred to us because of an enlarging mass in the left inferonasal limbus. The lesion had been excised at another institution but recurred 6 weeks postoperatively. On examination, her best-corrected visual acuity was 20/20 OD and 20/60 OS due to irregular astigmatism. The right eye was normal. The left eye revealed a yellow limbal mass between the 7:30 and 10-o’clock meridians, with marked corneal involvement (Figure 1A). Gonioscopy showed no intraocular involvement; however, the lesion reached the deep corneal stroma without breaching the Descemet membrane. The patient was systemically well . A 10-mmdiameter en bloc excision with a tectonic corneoscleral graft was performed. After more than 9 years of follow-up, there has been no recurrence of the tumor, and the visual acuity is stable at 20/60 OS (Figure 1B). Light microscopic examination of the lesion showed a hypercellular tumor consisting of oil red O–positive histiocytes and fibrocytes in a matted or storiform arrangement and invading deep corneal stroma and superficial sclera. Occasional giant cells of the Touton type were evident. No mitoses were seen (Figure 1C and D). Immunohistochemical analysis showed that both histiocytes and fibroblasts were positive for vimentin but negative for S100 protein and CD68 antigen (reactive macrophages). Electron microscopic studies disclosed that most cells were histiocytic, with an indented nucleus and reticulated nucleolus (results not shown). A scattered inflammatory infiltrate consisting predominantly of lymphocytes and plasma cells was observed. Case 2. A 12-year-old white girl had a 6-month history of an increas-

Einfluss des Innendrucks auf die Schnittwinkel in Humanhornhäuten bei der Spendertrepanation mit dem Er : YAG-Laser für die perforierende Keratoplastik

Abstract: BACKGROUND AND PURPOSE Congruent cut surfaces are a predisposition for good apposition of donor and recipient during penetrating keratoplasty (PK) The purpose of this study was to assess the impact of the intracameral pressure during nonmechanical donor trephination from the epithelial side on the cut angles for experimental human PK METHODS With a Q-switched 294 micro m Er : YAG laser a 6 mm sized corneal donor trephination was performed subtotally in 30 human corneas using an artificial anterior chamber device allowing different intracameral pressures (10, 20, and 40 mm Hg) The cut angles were measured immediately after the trephination by ultrasound biomicroscopy (UBM) at four quadrants: between trephination cut and corneal epithelium (angle 1 = A1-UBM) and between trephination cut and horizontal plane (angle 2 = A2-UBM) The positions of the measures were marked, the corneas were fixed in a buffered 10 % paraformaldehyde solution, and the same positions were analyzed by histology The histological cuts were digitized, the images printed, and the cut angles measured in paper (A1-histology) RESULTS Mean angles were 1116 degrees /1135 degrees /1266 degrees (A1-UBM), 884 degrees /935 degrees /1018 degrees (A2-UBM) and 1204 degrees /1251 degrees /1193 degrees (A1-histology) with 10/20/40 mm Hg, respectively The A2-UBM showed a significant increase of divergence with increasing intracameral pressure (p 009) CONCLUSIONS Increasing intracameral pressure using an artificial anterior chamber during donor trephination from the epithelial side for nonmechanical PK using Er : YAG laser results in increasing divergence of cut angles This may disturb the congruence of the cut angles in donor-recipient apposition To achieve standardised cut angles for a good donor recipient apposition, similar normotonic intracameral pressures for donor and recipient trephination should be attempted The UBM has the potential to analyse the cut angle immediately after subtotal trephination preserving the attempted intracameral pressure in the artificial anterior chamber Histological analysis of the cut angles seems to lack methodological validity

Q-switched 2.94-μm Er:YAG laser trephination With convergent and divergent cut angles for penetrating keratoplasty

Abstract: PURPOSE To study the morphologic properties of perpendicular (P), convergent (C), and divergent (D) cut angles using different speeds of rotations during donor and recipient nonmechanical trephination for experimental penetrating keratoplasty. METHODS With a Q-switched 2.94-microm Er:YAG laser corneal trephination was performed in 150 enucleated porcine eyes using ceramic open masks with 8 "orientation teeth/notches" and an automated globe rotation device allowing different cut angles [0 degree (P), 10 and 20 degrees (C and D)] toward the optical axis and variation of the rotation speed [3, 7, and 11 rotations per minute (rpm)]. The regularity of the cut (I, regular; II, slightly irregular; III, irregular) was assessed by light microscopy. The area of thermal damage and the number and size of "spikes" in the stroma at the superficial, intermediate and deep level of the excision were analyzed using digital images and the Optimas image processing software. RESULTS The regularity of the cut was classified as I in 42%/22% of donor/recipient and as II in 41%/56%, respectively. The thermal damage was least expressed with D20 degree cut angle and donor mask (P < 0.01). With all cut angles and speeds of rotation, thermal damage at the deep level of excision was significantly smaller (P < 0.01). With different speeds of donor rotations, the thermal damage showed no significant difference. With recipient trephination, the thermal damage at the deep level was greatest with 7 rpm (P < 0.01). The number and size of spikes of thermal damage with donor and recipient masks were significantly smaller in the deep stroma (P < 0.01). CONCLUSIONS Q-switched Er:YAG laser trephination with appropriate settings results in low thermal damage zones at the cut margin. Different cut angles and speeds of trephination may affect the cut performance and quality of the excision. In our study, low rotation speed and divergent donor cut angles showed the best results. The cut quality and the small thermal damage with the Q-switched 2.94-microm Er:YAG laser seem to be tolerable for corneal trephination. Therefore, this modality may be a low-cost, easy-to-handle alternative for nonmechanical corneal transplantation in humans.

Conjunctival Melanoma With a Positive Sentinel Lymph Node

Abstract: This study was supported in part by the Alexander von Humboldt Foundation, Bonn, Germany, and the Royal Australian and New Zealand College of Ophthalmologists and Sydney Eye Hospital, Sydney (Dr Conway) The authors have no relevant financial interest in this article We acknowledge the excellent technical assistance of Carmen Hofmann-Rummelt Corresponding author and reprints: R M Conway, MD, PhD, Department of Ophthalmology and Eye Hospital, University ErlangenNurnberg, Schwabachanlage 6, D-91054 Erlangen, Germany (e-mail: rmaxconway@hotmailcom)