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Corneal dystrophies are a rare group of hereditary disorders, that are bilateral, non-inflammatory, and progressive. Clinically, they can be classified based on the anatomic layer of the cornea affected. Refractive surgery and phototherapeutic keratectomy (PTK) can be performed with caution in patients with certain corneal dystrophies, but should be avoided in others. For epithelial basement membrane dystrophy, photorefractive keratectomy (PRK) is the procedure of choice for treatment of refractive error, and PTK may be performed for the treatment of recurrent erosions or irregular astigmatism. PRK and laser-assisted in situ keratomileusis (LASIK) have been associated with exacerbation of combined granular-lattice corneal dystrophy. LASIK and PRK appear to be safe in mild forms of posterior polymorphous corneal dystrophy, whereas LASIK should be avoided in Fuchs dystrophy. The safety of refractive surgery and PTK in the remainder of epithelial, Bowman layer, and stromal dystrophies has yet to be established.

A 48-year-old woman with no significant past history underwent bilateral simultaneous laser in situ keratomileusis for correction of her myopia. On the tenth postoperative day, the patient complained of visual decrease and photophobia. Slit lamp exam showed corneal epithelial irregularities. Confocal microscopy was performed and revealed a characteristic appearance of epithelial basement membrane dystrophy (EBMD). The patient was successfully treated with artificial tears and autologous serum eyedrops. EBMD may be missed before LASIK surgery, even after a careful pre-operative examination. Exacerbation of EBMD after LASIK surgery is rare. It should be considered when unexplained corneal epithelial defects or irregularities occur following LASIK. Confocal microscopy is very useful to confirm the diagnosis.

Purpose To ascertain the effects of aging on corneal morphology and to illustrate the morphologic diversity of the different layers in the normal cornea as seen by in vivo confocal microscopy (IVCM). Design Observational cross-sectional study. Participants A total of 150 healthy subjects, evenly distributed over 5 age categories, comprising 75 men and 75 women. Methods Both transparent corneas (n = 300) of all subjects were examined in duplicate by white light IVCM (Confoscan 4, NIDEK Technologies, Albignasego, Padova, Italy). After reviewing the IVCM examinations for morphologic variations of the corneal layers, we selected the 8 most common features to illustrate the morphologic diversity. Subsequently, all 600 IVCM examinations were assessed for the presence of these features. We used binary logistic regression analyses to assess the age-relatedness of each feature. Main Outcome Measures Age distribution of bright superficial epithelial cells, dendriform cells, alterations characteristic of epithelial basement membrane dystrophy (EBMD), tortuous stromal nerves, stromal microdots in the anterior stroma, folds in the posterior stroma, opacification of Descemet's membrane, and corneal guttae. Results Four features were found characteristic of the aging cornea: stromal microdots in the anterior stroma ( P P P P P = 0.09). Other features, such as bright superficial epithelial cells (n = 38, 13%), dendriform cells (n = 42, 14%), and tortuous stromal nerves (n = 115, 38%), were age-independent. We also found a novel phenotype of corneal endothelium in 4 normal eyes of 2 subjects, which we coined "salt and pepper endothelium." We could not establish whether this novel phenotype represented a morphologic variant of normal endothelium, an early stage of a known corneal endothelial disorder, or a completely new disease entity. Conclusions Knowledge of the common morphologic variations of the corneal layers and the effects of aging on corneal morphology as seen by IVCM increases our understanding of corneal degenerative disorders and is essential to detect corneal pathology. Our finding of a novel phenotype of corneal endothelium emphasizes the morphologic diversity of this optically transparent tissue. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Objective To evaluate the outcome of phototherapeutic keratectomy (PTK) treatment of epithelial basement membrane dystrophy (EBMD) patients and to examine clinical and morphologic signs of recurrent dystrophy. Design Cross-sectional, clinic-based study. Participants Fifty-two eyes of 39 patients diagnosed with EBMD who underwent PTK between 2001 and 2008. Methods Preoperative symptoms, best spectacle-corrected visual acuity (BSCVA), and refraction data were collected. At follow-up, refraction and BSCVA were measured, symptoms were noted, and slit-lamp biomicroscopy and in vivo confocal microscopy (IVCM) were performed. Main Outcome Measures Best spectacle-corrected visual acuity and signs of recurrent EBMD based on symptoms and morphologic features. An assessment of EBMD severity after PTK additionally was considered. Results Mean follow-up time was 43 months (range, 7–100 months). After PTK, BSCVA remained unchanged or improved in 49 (98%) of 51 eyes. Twenty-four (46%) of 52 eyes had recurrence of some form, and recurrence was correlated positively with postoperative time ( P Conclusions Although PTK is an effective method of alleviating the clinical symptoms of EBMD, the dystrophy can recur with time. The relationship between the postoperative development of clinical symptoms and the corneal morphologic features is complex and requires further investigation. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Purpose To describe corneal changes in patients with epithelial basement membrane dystrophy (EBMD) using a new in vivo confocal microscope. Design Observational case series. Methods A retrospective chart review of 22 consecutive patients with EBMD at the Quinze-Vingts National Ophthalmology Hospital from April 2004 to March 2005 was conducted. Gender, age, history of painful episodes suggestive of recurrent erosions, best-corrected visual acuity, slit lamp findings, and in vivo confocal microscopy images were analyzed. Results There were 8 male (36.4%) and 14 female (63.6%) subjects. Eighteen patients (81.2%) had a history of recurrent erosions in 1 or in both eyes. In 37 eyes of 19 patients (86.4%), map and/or dot and/or fingerprint changes were observed biomicroscopically. In 3 patients (13.6%) with recurrent erosions, the cornea had a normal structure on slit lamp examination and the diagnosis of EBMD was made after in vivo confocal microscopy examination. Four patients (18%), despite basement membrane abnormalities, reported no corneal symptoms suggesting recurrent erosions. In vivo confocal microscopy images showed that all patients had an abnormal epithelial basement membrane protruding into the corneal epithelium, epithelial cell abnormalities, and microcysts. No abnormalities were observed in superficial epithelial cells or the stroma. Conclusion Epithelial basement membrane dystrophy is characterized by an abnormal basement membrane protruding toward the epithelium and epithelial microcysts. In vivo confocal microscopy using the HRT II Rostock Cornea Module provides better resolution and therefore outlines distinctively in vivo microstructural characteristics of EBMD. It assists in the diagnosis of EBMD in patients suffering from recurrent erosion syndrome, particularly in patients with no corneal change visible biomicroscopically.

PURPOSE: To report sloughing of corneal epithelium during laser in situ keratomileusis and subsequent wound healing complications in patients with epithelial basement membrane dystrophy. METHODS: In a retrospective study, the surgical procedures, postoperative course, and visual acuities of 16 eyes of nine patients with epithelial basement membrane dystrophy who underwent laser in situ keratomileusis complicated with epithelial sloughing at three centers were reviewed. The mean follow-up period was 23 weeks (range, 4 to 52 weeks). RESULTS: In 13 (81%) of 16 eyes with epithelial basement membrane dystrophy, epithelial sloughing occurred during laser in situ keratomileusis. In eight of the 13 eyes, epithelial growth beneath the flap was observed. The flap was lifted and the interface epithelium scraped in six eyes. Flap melt or keratolysis occurred in four eyes. At the last follow-up visit, 13 of 16 eyes had an uncorrected visual acuity of 20/30 or better, and all eyes had a best-corrected visual acuity of 20/30 or better. CONCLUSIONS: Patients with epithelial basement membrane dystrophy have poorly adherent corneal epithelium and are predisposed to epithelial sloughing during the microkeratome pass of laser in situ keratomileusis. This may lead to flap distortion, interface epithelial growth, flap keratolysis, and corneal scarring. It is not recommended that laser in situ keratomileusis be performed in patients with classic, symptomatic epithelial basement membrane dystrophy. In patients who present with mild and asymptomatic epithelial basement membrane dystrophy, laser in situ keratomileusis should be performed with caution, or photorefractive keratectomy may be the preferred refractive procedure.

Objective To characterize morphologic changes in corneas of patients with recurrent erosion syndrome or epithelial basement membrane dystrophy using in vivo confocal microscopy. Design Observational case series Participants Fourteen eyes of eight patients with diagnosed epithelial basement membrane dystrophy and 13 eyes of seven patients with recurrent erosion syndrome were examined. Methods Slit-lamp examination and in vivo confocal microscopy. The pathologic findings are presented as digitized images obtained from video tape recorded during the confocal microscopy. Main outcome measures The morphology of corneal surface epithelial cells, basal epithelial cells, subbasal nerve plexus, Bowman's layer, stromal keratocytes, and endothelium was analyzed. Results The surface epithelium was intact in all but two eyes. One cornea (a basement membrane disorder with clinically visible dots) had multinucleate surface epithelial cells, and one eye with recurrent corneal erosions showed a freely floating surface epithelium sheet in the tear fluid. Patients in both groups showed islets of highly reflective cells with presumed intracellular deposits surrounded by normal cells in the basal epithelial cell layer. The basal epithelial cell area also showed other pathologic changes, including drop-shaped configurations, streaks, or ridges. Folding of the Bowman's layer was also observed in both groups. Anterior keratocytes showed signs of activation (highly reflective nuclei with visible processes) in some of the patients regardless of the clinical diagnosis, and in recurrent erosions even increased deposition of abnormal extracellular matrix in the anterior stroma was suspected. Posterior corneal keratocytes and endothelium appeared normal when examined. The subbasal nerve plexus showed various pathologic changes, such as short or strangely shaped nerve fiber bundles, decreased numbers of long nerve fiber bundles, only faintly visible long nerve fiber bundles (instead of the normally observed long parallel running interconnected bundles), or increased amounts of Langerhans cells, but only one patient (with recurrent erosion syndrome) lacked the subbasal nerve plexus. Conclusions In vivo confocal microscopy of corneas with recurrent erosions or epithelial basement membrane dystrophy showed deposits in basal epithelial cells, subbasal microfolds and streaks, damaged subbasal nerves, or altered morphology of the anterior stroma. Confocal microscopy cannot replace biomicroscopy in making a specific diagnosis, but it sometimes helps the diagnosis in corneas that appear normal under a biomicroscope.

Objective This study aimed to describe the morphology of cystic disorders of the corneal epithelium by confocal microscopy. Design The study design was a prospective evaluation of confocal microscopic images of patients with cystic corneal disorders. Participants Thirteen patients (19 eyes) were included. The corneal disorders included four patients with corneal decompensation (Fuchs’ dystrophy), five patients with epithelial basement membrane dystrophy (e.g., Cogan’s microcystic and map-dot dystrophies), one patient with Meesmann’s dystrophy, and three patients with recurrent erosion syndrome of unknown etiology. Confocal images of diseased comeas were compared with those of ten normal control eyes (ten subjects). Intervention All patients were examined by slit-lamp biomicroscopic analysis and confocal microscopic analysis (Tomey, Erlangen-Temmenlohe, Germany). Image analysis was used to identify the corneal epithelial structures correlated with the corresponding pathology. Main outcomes measures Confocal microscopy was used to assess the size, shape, light scatter, and reflection of the cysts. Results Slit-lamp examination results showed corneal epithelial cystic lesions in all cases. Confocal microscopy was able to identify cystic lesions in 9 (69.2%) of 13 patients. Of the four patients in whom lesions could not be found by confocal microscopy, three had recurrent erosion syndrome and the other one had epithelial basement membrane dystrophy. The confocal images were compatible with the clinical and histologic pictures of the disease. Normal control eyes did not show any epithelial lesion, either by biomicroscopy or confocal microscopy. Conclusions Confocal microscopy provides an in vivo evaluation of cystic epithelial corneal lesions. This study shows that confocal microscopy is suitable for examining cystic lesions of the corneal epithelium. Nevertheless, it is not as sensitive as biomicroscopy in detecting cystic lesions in certain corneal conditions.

Purpose To investigate the features of corneal epithelial basement membrane dystrophy using spectral-domain optical coherence tomography (SD OCT) and to examine the reliability of SD OCT in distinguishing epithelial basement membrane dystrophy from the normal cornea. Design Diagnostic test study. Methods Forty-five individuals with epithelial basement membrane dystrophy and 45 age- and sex-matched controls with normal corneas were examined, and SD OCT scans of their corneas were performed. In vivo confocal microscopy was performed to confirm or rule out the diagnosis of epithelial basement membrane dystrophy. The structural corneal changes occurring in eyes with epithelial basement membrane dystrophy based on SD OCT findings were described. Results Epithelial abnormalities were observed in 86 of 87 eyes with epithelial basement membrane dystrophy (45 patients) on SD OCT scans. The 2 main features were the presence of an irregular and thickened epithelial basement membrane duplicating or insinuating into the corneal epithelium layer, or both, and the presence of hyperreflective dots. In some cases, we detected hyporeflective spaces between the corneal epithelial layer and the Bowman layer similar to a corneal epithelial detachment. This corneal epithelial detachment sometimes was associated with a cleavage with a stair-step appearance within the corneal epithelial layer. We found a perfect correlation between in vivo confocal microscopy and SD OCT findings in the diagnosis of epithelial basement membrane dystrophy (κ = 0.98). Conclusions SD OCT provides an accurate assessment of the structural changes occurring in eyes with epithelial basement membrane dystrophy. These changes, visible on SD OCT scans, are easily detectable and permit an accurate diagnosis, especially in patients with no biomicroscopically visible corneal changes.

Subendothelial blebs were seen in cases of superficial keratopathy of varied etiology: superficial punctate keratopathy (42 patients); keratoconjunctivitis sicca (11 patients); epithelial basement membrane dystrophy (9 patients); mild superficial keratopathy due to exposure (9 patients), trichiasis (6 patients), or chemical contact (4 patients); and in contact-lens wearers (29 patients). The blebs were probably due to intercellular edema, separating endothelial cells from Descemet's membrane, and were reversible after resolution of the keratopathy. If the condition is chronic, changes in endothelial morphology may occur, with pleomorphism and polymegathism of the endothelial cells. These cases show that conditions which cause fine disruption of the corneal epithelium affect the integrity of the corneal endothelium. Recognition of resulting long-term changes may be important before intraocular surgery or if the cornea is to be used for grafting.