Comet Lesions in Patients with Pseudoxanthoma Elasticum.

Pseudoxanthoma elasticum (PXE) is a genetic multisystemic disorder affecting the skin, eyes and cardiovascular system. Basic fundoscopic findings in PXE result from Bruch's membrane involvement. The most important fundoscopic findings are angioid streaks. Other significant ocular findings are peau d'orange appearance, optic disc drusen, pattern dystrophy-like macular appearance, comet lesions, and choroidal neovascularization. Comet lesions are a pathognomonic ocular finding for PXE. The presence of both angioid streaks in the fundus and typical skin lesions should alert clinicians to PXE. Herein, we present two PXE cases with comet lesions.

AS-OCT as a tool for flap thickness measurement after femtosecond-assisted LASIK.

BACKGROUND AND OBJECTIVE: to investigate the efficacy of anterior segment optical coherence tomography (AS-OCT) for calculating flap thickness in femtosecond laser-assisted laser in situ keratomileusis. PATIENTS AND METHODS: fifty-one eyes of 26 patients with myopia and myopic astigmatism were included in this prospective study. High-resolution corneal images were evaluated at 1 week and 1 month postoperatively. Images along the horizontal meridian were measured with the flap tool at seven points. RESULT: measurements at vertex and at 1 mm nasally and temporally from the vertex were indistinct but easily defined. Although statistically not significant, flaps were found to be thinner in the central cornea and thicker in the periphery (P > .05). CONCLUSION: AS-OCT provides detailed high-resolution images for quantitative evaluation of the flap-stroma relationship, but it may not be precise in the central 2-mm area of the cornea. Despite this, AS-OCT is an imaging tool with significant utility.

In Vivo Confocal Microscopy in Presumed Central Cloudy Dystrophy of François.

A 70-years-old woman with no visual symptoms was incidentally diagnosed with presumed central cloudy dystrophy of François (CCDF) on regular ophthalmic examination. Bilateral polygonal opacities separated by clear spaces were seen in corneal biomicroscopic examination. The opacities were prominent in the central cornea and occupied full-thickness corneal stroma. Confocal microscopy revealed small highly refractile granules and deposits in the anterior and deeper stromal layers. Multiple dark acellular striae among extra-cellular matrices with increased intensities were seen in the posterior stroma. No stromal layer of keratocytes was observed. In the right eye, the corneal endothelial cell density was 3,319 cells/mm(2), polymegathism was 52.9%, and pleomorphism was 34.3%. In the left eye, endothelial cell counts could not be performed because of high stromal reflectance intensity. Full-thickness involvement of the corneal stroma with hyperreflective granules and microstriae and absence of keratocytes may represent a more advanced stage of the dystrophy.

Visante anterior segment OCT in a patient with gas bubbles in the anterior chamber after femtosecond laser corneal flap formation.

A patient with anterior chamber gas bubbles after LASIK flap formation with femtosecond laser is presented. A 33-year-old male patient had LASIK for myopia with corneal flap formation with IntraLase FS30 femtosecond laser. In the right eye, air bubbles were observed in anterior chamber after successful flap formation. Laser correction was completed successfully, by Wavelight Allegretto Wave Eye-Q excimer laser, without eye-tracker. Visante anterior segment optical coherence tomography imaging displayed that the pocket extended to limbal area, with stromal bed thickness of >600 microm at that area. We propose as possible causes of the air bubbles scattering of femtosecond laser beam producing direct photodissociation of aqueous humor, or direct cavitation effect in aqueous humor due to rapid pressure changes in corneal lamellar interface during the femtosecond laser procedure. Other causes such as migration of intrastromal bubbles through peripheral corneal stroma and trabecular meshwork, or through posterior stroma and endothelium, seem to be unlikely.

The correlation between visual field defects and focal nerve fiber layer thickness measured with optical coherence tomography in the evaluation of glaucoma.

PURPOSE: To study the correlation between known visual field defects and retinal nerve fiber layer (RNFL) thickness detected by optical coherence tomography (OCT) in glaucomatous eyes. MATERIALS AND METHODS: Visual field parameters and OCT RNFL measurements of 28 eyes of 28 glaucoma patients with various stages of glaucoma were compared with 38 eyes of 38 normal age-matched controls. A perimetric nerve fiber bundle map was built by dividing the visual field area into 21 zones. Mean deviation and pattern standard deviation values within these 21 zones were compared with OCT RNFL thickness measurements in 12 sectors and the results were analyzed. RESULTS: Average RNFL thickness was 62.90+/-16.56 microm in the glaucoma group and 111.90+/-6.00 microm in the control group (P<0.05). Pattern standard deviation and mean deviation visual field zones and corresponding OCT RNFL thickness sectors were significantly correlated at specific sectors in the glaucoma group (P<0.01). CONCLUSIONS: Analysis of RNFL thickness in eyes with focal glaucomatous visual field defects showed good structural and functional correlation with OCT. OCT contributes to the identification of focal defects in the RNFL of glaucoma patients.

Evaluation of corneal topography with Orbscan II in first-degree relatives of patients with keratoconus.

PURPOSE: To evaluate the corneal topographic characteristics of first-degree relatives of patients with keratoconus with corneal topography to determine the incidence of clinical keratoconus and topographic abnormalities. METHODS: Between February and August 2006, Orbscan II analysis was done in 144 eyes of 72 cases who were first-degree relatives of patients diagnosed with clinical keratoconus. The findings were compared with preoperative Orbscan analyses of 52 clinically normal individuals who underwent laser in situ keratomileusis surgery and did not develop corneal ectasia in 3 years of follow-up. RESULTS: In 8 of the 72 first-degree relatives of patients with keratoconus, clinical keratoconus was diagnosed by the topographic pattern in Orbscan and clinical examination (group 1). The remaining 64 subjects (group 2) were compared with the control group (group 3). The central corneal thickness was 523.7 +/- 40.4 microm in group 2, whereas it was 546.3 +/- 33.1 microm in group 3 (P < 0.05). The central corneal thickness, thinnest pachymetric reading, posterior elevation value, distance between the greatest anterior/posterior elevation points, and corneal center, posterior best fit sphere (BFS) values, posterior BFS:anterior BFS ratio, and irregularity values were significantly different between group 2 and group 3 (P < 0.05). CONCLUSIONS: The keratoconus incidence was found to be 11% in first-degree relatives of patients with keratoconus as opposed to a reported incidence of keratoconus of 0.05% in the general population. In first-degree relatives of patients with keratoconus who did not have a topographic keratoconus pattern, abnormal corneal topographic values were detected. The asymptomatic relatives of patients with keratoconus should undergo a thorough preoperative analysis for subtle topographic abnormalities before any keratorefractive surgery.

Clinicopathological features of ocular cystinosis.

A 31-year-old woman who presented with photophobia was found to have bilateral corneal and conjunctival crystal deposition. Ocular cystinosis was diagnosed upon observation of typical crystals and lack of systemic involvement. In vivo confocal microscopy confirmed crystal deposition of the corneas and conjunctivae bilaterally. Optical coherence tomography showed stromal hyper-reflectivity due to crystals within the corneal stroma. Transmission electron microscopy of the conjunctiva demonstrated pathognomonic intralysosomal cystine crystals inside fibroblasts and macrophages. Clinicopathological characteristics of ocular cystinosis are well described by this exceptional case.