圆锥角膜的共焦显微镜表现临床分级

目的 观察临床上不同阶段圆锥角膜的共焦显微镜图像，推测圆锥角膜的病理发展过程，并进行圆锥角膜的共焦显微镜分级。方法 采用共焦显微镜（Confoscan 2．0），观察24例24眼不同发展阶段（lawless分期）圆锥角膜患者的角膜共焦显微镜图像，进行分析并提出焦显微镜下的临床分分期。结果 共焦显微镜下圆锥角膜首先出现了排列规则的裂隙状暗纹，随着病情的不断进展，病变逐渐由角膜后弹力层向前发展，逐渐累及角膜的后基质和前基质，同时角膜基质细胞核拉长、排列出现紊乱，前后基质细胞失去了原有特征。急性圆锥角膜的患者角膜基质细胞出现水肿，角膜瘢痕在共焦显微镜下呈强反光的无细胞样结构。讨论 共焦显微镜下圆锥角膜的病理发展过程，是从角膜后弹力层开始，由后向前发展，逐渐累及角膜的后基质、前期基质，最后角膜破裂引起急性圆锥角膜，角膜出现水肿，愈合后遗留瘢痕。据此提出圆锥角膜共焦显微镜分期将为四个阶段：第一阶段、角膜裂隙样暗纹累及角膜后弹力层；第二阶段、角膜裂隙样暗纹累及角膜后后基质；第三阶段、角膜裂隙样暗纹累及角膜前基质；第四阶段、出现角膜基质水肿或者瘢痕。     

In vivo confocal microscopy in the patients with cornea farinata

PURPOSE: To report in vivo corneal confocal microscopic findings of patients with cornea farinata. PATIENTS AND METHODS: Two unrelated patients, a 47-year-old man and a 77-year-old woman, with cornea farinata were studied. Examination with a confocal microscope was performed in addition to routine slit-lamp biomicroscopy. RESULTS: In both cases, slit-lamp biomicroscopy showed numerous small, faint opacities in the deep stroma in both eyes. Using confocal microscopy, highly reflective small particles were observed in the cytoplasm of keratocytes in the deep stroma adjacent to the corneal endothelial layer. No abnormalities could be detected in the epithelial layer, in the mid-stromal layer, at the level of Descemet's membrane, and in the endothelial layer. CONCLUSIONS: In vivo corneal confocal microscopy is useful for observing stromal abnormalities in cornea farinata. Further investigation of posterior stromal opacities using confocal microscopy may be useful to understand and differentiate various corneal conditions involving primarily deep stromal layers.     

圆锥角膜各期的共焦显微镜表现

目的评价共焦显微镜在圆锥角膜临床研究中的应用价值。方法应用共焦显微镜观察圆锥角膜患者32例（48眼）及正常对照组17例（28眼），分别比较早、中、晚期圆锥角膜与正常对照组的图像特点。结果早期圆锥角膜出现激活状态的角膜细胞、浅基质层的细小皱褶、深基质层的暗纹、部分内皮细胞异形性明显，中、晚期圆锥角膜出现角膜上皮细胞拉伸、细胞核皱缩；基质细胞排列紊乱、基质层暗纹；而对照组未发现上述表现。各期圆锥角膜的角膜基质层厚度、不同深度角膜基质细胞密度、内皮细胞密度与对照组之间差异有统计学意义（P〈0．05）。结论共焦显微镜对早期圆锥角膜的发现以及圆锥角膜病理发展的研究具有重要的临床价值。     

Corneal cross-linking-induced stromal demarcation line

PURPOSE: Corneal collagen cross-linking by UVA/riboflavin (X-linking) represents a new method for the treatment of progressive keratoconus and currently is under clinical study. To avoid UVA irradiation damage to the corneal endothelium, the parameters for X-linking are set in a way that effective treatment occurs only in the first 300 microm of the corneal stroma. Here, X-linking not only strengthens the biomechanical properties of the cornea but also induces keratocyte apoptosis. To date, the effectiveness of treatment could be monitored only indirectly by postoperative follow-up corneal topographies or using corneal confocal microscopy. Here we describe a corneal stromal demarcation line indicating the transition zone between cross-linked anterior corneal stroma and untreated posterior corneal stroma. The demarcation line is biomicroscopically detectable in slit-lamp examination as early as 2 weeks after treatment. METHODS: X-linking was performed in 16 cases of progressive keratoconus, and corneas were examined biomicroscopically and by means of corneal topography and pachymetry before and after treatment. RESULTS: In 14 of 16 cases, a thin stromal demarcation line was visible at a depth of approximately 300 microm over the whole cornea after X-linking treatment. CONCLUSION: This newly observed demarcation line may result from differences in the refractive index and/or reflection properties of untreated versus X-linked corneal stroma and represents an effective tool to biomicroscopically easily monitor the depth of effective X-linking treatment in keratoconus.     

In vivo corneal confocal microscopic findings of palisades of Vogt and its underlying limbal stroma

PURPOSE: To demonstrate the corneal confocal microscopic findings of limbal palisades of Vogt and its underlying limbal stroma. METHODS: Two unrelated healthy subjects (a 56-year-old man and a 40-year-old man) with prominent palisades of Vogt were enrolled in this study. A detailed examination with confocal microscopy was performed in addition to a routine slit-lamp biomicroscopy. Cell sizes of epithelial basal layers of both the central and limbal (beneath the palisades of Vogt) were measured and statistically analyzed. RESULTS: In both subjects, confocal microscopy in the region of the palisades of Vogt revealed normal appearance of corneal superficial layers. However, in some images, undulant basal epithelial layer was observed. In the superficial stromal layer adjacent to the corneal epithelium, we noted corneal nerves that seemed to terminate at the epithelial basal layers. The mid-stromal layers showed a highly reflective spatter-like pattern as well as numerous dark striae in a branching pattern. The corneal endothelial layer seemed normal. The average cell size of epithelial basal cells beneath the palisades of Vogt was significantly smaller than those of the central cornea (P = 0.015 and 0.005 in cases 1 and 2, respectively). CONCLUSIONS: In vivo corneal confocal microscopy is useful in observing limbal stromal microstructures. Further investigations of pathologic corneal limbus may be useful in elucidating the mechanisms contributing to corneal limbal epithelial stem cell deficiency.     

The alterations in corneal structure at III/IV stage of keratoconus by means of confocal microscopy and ultrasound biomicroscopy before penetrating keratoplasty

PURPOSE: The aim of the study was in-real time observation and morphological evaluation of the human corneas at III/IV stage of keratoconus, using the scanning slit confocal microscope Confoscan P4 and ultrasound biomicroscopy--UBM. MATERIAL AND METHODS: The patients with keratoconus were examined according to the Amsler scale. The material consisted of 12 corneas of 11 patients (8 men, 3 women), where assessment of the corneal structure was performed with the confocal microscope ConfoScan P4 (Tomey) and ultrasound biomicroscopy--UBM Model 840 (Humphrey Instruments). The comparison of different corneal regions (central and peripheral) was evaluated. RESULTS: The confocal microscopy and UBM revealed thinning of the layers of the corneal structure and pathological changes in the central area, especially at IV stage of keratoconus. The desquamating superficial cells were elongated, arranged around the apex of the cornea. Below the Bowman's membrane a considerable disarrangement of collagen fibers reflected by bright background illumination was observed. In the posterior part of the stroma the folds were detected. The examination of the cornea showed thickening in the peripheral part, central detachment of the Descemet's membrane and the endothelium from the posterior surface of the cornea. The thickness of the cornea varied from 0.201 to 0.384 mm in the central part and 0.675 to 0.740 mm in the peripheral area. CONCLUSION: Confocal scanning microscopy combined with ultrasound biomicroscopy enables the cornea to be examined in vivo. It can be used to localize pathological changes in individual corneal layers and to assess their extent.     

Collagen fiber diameter in the rabbit cornea after collagen crosslinking by riboflavin/UVA

OBJECTIVE: Collagen crosslinking of the cornea has been developed recently as a quasiconservative treatment of keratoconus. Biomechanical in vitro measurements have demonstrated a significant increase in biomechanical stiffness of the crosslinked cornea. The aim of the present study was to evaluate the effect of this new procedure on the collagen fiber diameter of the rabbit cornea. METHODS: The corneas of the right eyes of 10 New Zealand White albino rabbits were crosslinked by application of the photosensitizer riboflavin and exposure to UVA light (370 nm, 3 mW/cm2) for 30 minutes. The left fellow control eyes were either left untreated (rabbits 1-4), deepithelialized (rabbits 5-7), or deepithelialized and treated with riboflavin/dextran solution (rabbits 8-10) to exclude an influence of epithelial debridement or hydration changes on the fiber diameter. On ultrathin sections of samples from the anterior and posterior cornea, the collagen fiber diameter was measured semiautomatically with the help of morphometric computer software. RESULTS: In the anterior stroma, the collagen fiber diameter in the treated corneas was significantly increased by 12.2% (3.96 nm), and in the posterior stroma by 4.6% (1.63 nm), compared with the control fellow eyes. In the crosslinked eyes, the collagen fiber diameter was also significantly increased by, on average, 9.3% (3.1 nm) in the anterior compared with the posterior stroma within the same eye. CONCLUSIONS: Collagen crosslinking using riboflavin and UVA leads to a significant increase in corneal collagen diameter. This alteration is the morphologic correlate of the crosslinking process leading to an increase in biomechanical stability. The crosslinking effect is strongest in the anterior half of the stroma because of the rapid decrease in UVA irradiance across the corneal stroma as a result of riboflavin-enhanced UVA absorption.     

In vivo microstructural analysis of the cornea in Maroteaux-Lamy syndrome

PURPOSE: This report describes the clinical and in vivo microstructural features of the cornea in a case of Maroteaux-Lamy syndrome. METHODS: A 17-year-old female with Maroteaux-Lamy syndrome was examined by slit-lamp biomicroscopy, Orbscan II slit-scanning elevation topography, and in vivo confocal microscopy. RESULTS: Slit-lamp biomicroscopy revealed bilateral, altered corneal transparency involving the posterior half of the stroma. Funduscopy revealed bilateral small, crowded optic discs, and radial macula retinal folds.On in vivo confocal microscopy, the middle and posterior stroma were clearly visualized and exhibited well-defined, unusually shaped keratocytes. These cells contained single or multiple hyporeflective regions with well-defined borders that ranged from 1 to 11.6 microm in diameter. These abnormal keratocytes were particularly abundant in the posterior stroma and sparse in the anterior stroma. CONCLUSIONS: This is the first case of Maroteaux-Lamy syndrome in which altered corneal transparency has been imaged by in vivo confocal microscopy and macula retinal folds have been described.     

Structural changes in the cornea after LASIK-u during the early postoperative period

PURPOSE: The study aimed to evaluate in vivo the corneal structure after refractive surgery and monitor morphologic and morphometric changes in the post-operative period. MATERIAL AND METHODS: The study included 35 eyes (25 patients) who underwent LASIK correction of myopia. The structure of the cornea was evaluated in vivo using a scanning slit confocal microscope. Each cornea was examined before, 2, 4 and 8 weeks after procedure. The keratocyte density was evaluated morphometrically in the anterior and posterior corneal stroma. RESULTS: Before surgery the keratocyte density in the anterior stroma ranged from 900 to 1200/mm2, while in the posterior stroma it ranged from 600 to 950/mm2. 8 weeks after LASIK the keratocyte density in anterior stroma ranged from 695 to 1048/mm2 and in posterior stroma from 565 to 935/mm2. CONCLUSIONS: After LASIK the keratocyte density decreases in anterior stroma while in posterior stoma it is constant.     

Changes in corneal structure observed with confocal microscopy during Fuchs endothelial dystrophy

PURPOSE: The study aimed to in vivo evaluate corneal structure in Fuchs' dystrophy. MATERIAL AND METHODS: Forty-two eyes of 21 patients (11 women and 10 men) aged 34-80 (mean 60.8) were studied. Sixteen patients presented clinical symptoms. The cornea was examined using a Confoscan P4 scanning slit confocal microscope (Tomey). Before examination, the cornea was anesthetized with 0.5% propacaine (Alcaine, Alcon) in order to inhibit the corneopalpebral reflex. A 40x microscope objective was covered with a drop of polyarylic acid gel (Vidisic, Mann Pharma) and then it was moved horizontally close to the patient's cornea and the examination was carried out. RESULTS: In the early stage of Fuchs dystrophy, slit biomicroscopy revealed fine dark spots within the corneal endothelium, while in the advanced stage the cornea had the appearance of beaten metal. On confocal microscopy, there were diffused hyporeflective areas in the early-stage disease. The endothelial cells located beyond these areas were pleomorphic and polymegathic. In the late stage we observed diffused hyporeflective areas surrounded by hyperreflective endothelial cells, which could not be analyzed separately. Within the corneal stroma, the collagen fibers were blurred and the background illumination was increased. In the posterior part of the stroma, dark bands were seen. The epithelium contained cystic structures (blisters). The membranes of the basal cells were thickened and the background illumination was increased. CONCLUSIONS: Confocal microscopy allows to diagnose Fuchs dystrophy and visualize endothelial cells within the swollen cornea.     

Confocal microscopy of subepithelial infiltrates occurring after epidemic keratoconjunctivitis

PURPOSE: To describe the confocal microscopic findings in subepithelial infiltrates associated with epidemic keratoconjunctivitis (EKC). METHODS: Observational case report. RESULTS: A 14-year-old Saudi girl with keratoconus developed subepithelial infiltrates (SEIs) after the onset of bilateral EKC. Confocal microscopy of the left cornea 8 weeks after the onset of EKC showed many highly reflective dendritic cells at the level of basal epithelium, epithelial basement membrane zone, and anterior stroma, as well as many highly reflective fusiform and round cells within the anterior stroma, with deceasing density in progressively deeper layers of the stroma. These findings were not present on confocal microscopy that had been performed 2 weeks before the onset of EKC. CONCLUSION: Confocal microscopic examination of SEIs after EKC provides evidence of an inflammatory response localized to the basal epithelium and anterior stroma of the central cornea.     

Confocal microscopy of subepithelial infiltrates occurring after epidemic keratoconjunctivitis

PURPOSE: To describe the confocal microscopic findings in subepithelial infiltrates (SEIs) associated with epidemic keratoconjunctivitis (EKC). METHODS: Observational case report. RESULTS: A 14-year-old Saudi girl with keratoconus developed SEIs after the onset of bilateral EKC. Confocal microscopy of the left cornea 8 weeks after the onset of EKC showed many highly reflective dendritic cells at the level of basal epithelium, epithelial basement membrane zone, and anterior stroma, as well as many highly reflective fusiform and round cells within the anterior stroma, with decreasing density in progressively deeper layers of the stroma. These findings were not present on confocal microscopy that had been performed 2 weeks before the onset of EKC. CONCLUSION: Confocal microscopic examination of SEIs after EKC provides evidence of an inflammatory response localized to the basal epithelium and anterior stroma of the central cornea.     

Corneal opacity in lumican-null mice: defects in collagen fibril structure and packing in the posterior stroma

PURPOSE: Gene targeted lumican-null mutants (lum(tm1sc)/lum(tm1sc)) have cloudy corneas with abnormally thick collagen fibrils. The purpose of the present study was to analyze the loss of transparency quantitatively and to define the associated corneal collagen fibril and stromal defects. METHODS: Backscattering of light, a function of corneal haze and opacification, was determined regionally using in vivo confocal microscopy in lumican-deficient and wild-type control mice. Fibril organization and structure were analyzed using transmission electron microscopy. Biochemical approaches were used to quantify glycosaminoglycan contents. Lumican distribution in the cornea was elucidated immunohistochemically. RESULTS; Compared with control stromas, lumican-deficient stromas displayed a threefold increase in backscattered light with maximal increase confined to the posterior stroma. Confocal microscopy through-focusing (CMTF) measurement profiles also indicated a 40% reduction in stromal thickness in the lumican-null mice. Transmission electron microscopy indicated significant collagen fibril abnormalities in the posterior stroma, with the anterior stroma remaining relatively unremarkable. The lumican-deficient posterior stroma displayed a pronounced increase in fibril diameter, large fibril aggregates, altered fibril packing, and poor lamellar organization. Immunostaining of wild-type corneas demonstrated high concentrations of lumican in the posterior stroma. Biochemical assessment of keratan sulfate (KS) content of whole eyes revealed a 25% reduction in KS content in the lumican-deficient mice. CONCLUSIONS: The structural defects and maximum backscattering of light clearly localized to the posterior stroma of lumican-deficient mice. In normal mice, an enrichment of lumican was observed in the posterior stroma compared with that in the anterior stroma. Taken together, these observations indicate a key role for lumican in the posterior stroma in maintaining normal fibril architecture, most likely by regulating fibril assembly and maintaining optimal KS content required for transparency.     

In vivo confocal corneal microscopy after keratoplasty

BACKGROUND: Seven eyes with clear grafts after penetrating keratoplasty were examined with in vivo confocal corneal microscopy in 1999. Our aim was the confocal microscopic investigation of the subclinical changes in clear grafts after long-term follow-up.METHODS: The preoperative diagnoses were keratoconus (two), granular corneal dystrophy (two), pseudophakic bullous keratopathy due to ACL (two), and corneal ulcer (one). The epithelium, corneal nerves, keratocytes of the anterior and posterior stroma, and endothelium were evaluated with confocal microscopy.RESULTS: Mean density of basal epithelial cells was 3928+/-378 cells/mm(2) at 15 months and 3284+/-565 cells/mm(2) at 66 months postoperatively. At 15 months the keratocyte density was 750+/-113 cells/mm(2) in the anterior stroma and 601+/-98 cells/mm(2) in the posterior stroma, at 66 months 383+/-53 cells/mm(2) in the anterior stroma and 411+/-98 cells/mm(2) in the posterior stroma. Endothelial cell density decreased from 1719+/-576 cells/mm(2) (15 months) to 965+/-272 cells/mm(2) (66 months).CONCLUSIONS: In the follow-up period a significant decrease of keratocyte and endothelial cell density was detectable with confocal microscopy. The clinical importance of our findings must be clarified with further examinations on more patients.     

In vivo confocal microscopy findings in a patient with posterior amorphous corneal dystrophy

A 21-year-old man, with bilateral posterior amorphous corneal dystrophy, was studied by biomicroscopy, corneal topography and in vivo confocal microscopy. The best-corrected visual acuity was 6/21 in the right eye and 6/6.9 in the left eye. Biomicroscopy revealed bilateral, asymmetric, sheet-like opacification at the deep posterior stromal layer. The corneal topography displayed asymmetric against-the-rule astigmatism in the right eye and prominent steepening at the inferior paracentral cornea in both eyes. In vivo confocal microscopy of the corneas demonstrated microfolds and hyper-reflective layer at the posterior stroma just adjacent to the endothelial layer. The epithelium, Bowman's membrane, anterior stroma and the endothelial layer were normal. In vivo confocal microscopy is useful in evaluating the corneal dystrophies.     

Confocal microscopy of the cornea. Communication 2. Morphological changes in keratoconus

The paper presents the results of studying morphological changes in keratoconus by life-time confocal microscopy. A total of 50 patients (100 eyes) with grades 1-to-4 keratoconus were examined. The most pronounced changes were found in the corneal areas involved in an ectatic process. Four grades of epitheliopathy were conventionally identified in relation to the desquamation of superficial epitheliocytes, the change of their shape, impaired adhesion with the underlying layers, and transparency disorders. The indirect signs of altered Bowman's membrane were revealed. In early keratocons, the stroma showed hyperreflectivity of anterior layers, higher activated keratocytes, their changed shape and spatial orientation. The emergence of microstrium in the posterior stromal layers with their gradual spread to the midstroma and anterior stroma, abnormal transparency, and scarring were typical of the progress of the disease. There were processes of homogenization and fibrotization of stromal structure and fewer keratocytes. There might be changes in Descemet's membrane (undulating folds) and posterior epithelium (polymegatism, polymorphism, enlarged intercellular spaces, and cell apoptosis). Thus, confocal microscopy reveals certain regularities of a pathological process in keratoconus at different stages of the disease.     

In vivo confocal microscopy of patients with amiodarone-induced keratopathy

PURPOSE: To describe the corneal findings in patients with amiodarone-induced keratopathy by means of in vivo confocal microscopy. METHODS: Twenty-two eyes of 11 patients (eight men and three women) receiving amiodarone therapy and 20 eyes of 10 healthy sex-and age-matched control subjects were selected for confocal microscopic examination. The patients were examined by use of a scanning slit corneal confocal microscope (Confoscan 2.0). Five complete scans of the entire cornea were performed for each eye with a total examination time of less than 5 minutes. RESULTS: All patients receiving amiodarone showed the presence of high reflective, bright intracellular inclusions in the epithelial layers. These findings were more evident within the basal cell layers. In the eyes with advanced keratopathy (stages 2 and 3), bright microdots were detectable within the anterior and posterior stroma and on the endothelial cell layer. In the anterior stroma, the keratocyte density in the treated group was reduced compared with values of the control group (p < 0.001), and a markedly irregular aspect of the stromal nerve fibers was found. The main characteristic of this nerve irregularity was represented by the clew-shaped appearance of the nerve trunks. CONCLUSION: Detailed examination of corneal structure by confocal microscopy shows that amiodarone keratopathy in long-term treated patients presents some findings that are consistent with higher toxicity than was expected and that involve the deep corneal layers.     

Iron deposits in cornea in confocal microscope

PURPOSE: The study aimed to evaluate the iron deposits in corneas in confocal microscope. MATERIAL AND METHODS: The material comprised 16 eyes which underwent photorefractive keratectomy (PRK) procedure. The structure of corneas was evaluated between 3-10 years after PRK. The visual acuity after PRK was the same as the best corrected visual acuity before the procedure. The structure of corneas was evaluated in vivo using scanning slit confocal microscopy. The confocal images of corneas in patients after PRK were compared with confocal corneal images of patients with corneal scars (2 eyes), keratoconus (2 eyes), after radial keratotomy (RK) (2 eyes) and healthy patients. RESULTS: Within the central part of corneal epithelium and anterior part of stroma, the clusters of iron deposits were observed. They were round and produced different shapes. In the paracentral and peripheral part of corneas the subepithelial nerve plexus was detected. Beneath, the pattern of keratocytic nuclei, characteristic for state after PRK, was detected. In patients with corneal scars, keratoconus and after RK, the same clusters of deposits were detected. In cases of corneal scars, additionally high reflectivity of corneal structure was observed. CONCLUSIONS: The iron deposits in corneal structure arise in epithelium and anterior part of corneal stroma. The iron deposits which produce different shapes have no influence on visual acuity.     

圆锥角膜行去上皮角膜胶原交联术后角膜微结构的变化

目的：采用共焦显微镜观察进展期圆锥角膜行去上皮角膜胶原交联术后角膜微结构的变化。

方法：选取2016-02/2017-02于我院行上皮角膜胶原交联术治疗的进展期圆锥角膜患者11例15眼,分别于手术前后行共焦显微镜检查,观察角膜微结构变化。

结果：术后早期角膜上皮下神经纤维显著减少或消失; 角膜前基质呈蜂窝状,几乎无典型的角膜基质细胞,术后3mo基质细胞开始出现,术后12mo基质细胞数量几乎恢复到术前水平,但角膜上皮下神经仍稀疏,未达到术前水平; 术后后部角膜基质细胞和内皮细胞大小及形态未受影响。

结论：角膜胶原交联术后角膜微结构发生变化最明显的是上皮下神经纤维和前基质细胞,但随着随诊时间的延长,这种变化呈逐渐减弱趋势。     

Confocal microscopy imaging of the cornea in patients with silicone oil in the anterior chamber after vitreoretinal surgery

Objective Evaluation of corneal morphology by confocal microscopy after vitreoretinal surgery complicated by passage of silicone oil into the anterior chamber. Design Case series (case control study). Methods Eight patients (eight eyes) who had undergone vitreoretinal surgery and had silicone oil in the anterior chamber but no clinically evident corneal abnormalities made up the patient group. The control group consisted of eight patients (eight eyes) who had undergone vitreoretinal surgery with application of silicone oil tamponade but who had no silicone oil clinically observable in the anterior chamber. In vivo examination of the cornea using a ConfoScan 3 (Nidek Technologies) confocal microscope equipped with the standard 40× immersion lens was performed. Central, upper, and lower parts of the cornea were assessed separately. High-magnification evaluation of the status of corneal layers and endothelial cell density in upper parts of the cornea directly in contact with silicone oil in the anterior chamber and in parts of the cornea not in direct contact with silicone oil was carried out. Results Alterations in corneal morphology, especially in endothelium and posterior and medium stroma, were observed. In all cases, changes were more advanced in the upper part of the cornea. Endothelial cell density was significantly decreased in upper parts of the cornea. Conclusions In patients with silicone oil in the anterior chamber, confocal microscopy imaging reveals early morphological alterations of the cornea before their clinical manifestation. The authors have no financial or other interest in any products used or described in this study. No financial support was received. Presented in part at the annual meeting of the Deutsche Ophthalmologische Gesellschaft (DOG), Berlin, 2004