Valeria Sánchez-Huerta

Confocal microscopy of corneal flap microfolds after LASIK

PURPOSE To describe the morphological characteristics of microfolds that appear at the corneal flap after LASIK, as seen under confocal microscopy. METHODS Twenty-one eyes that had undergone LASIK were examined, all within 3 weeks to 1 month after surgery. A central scan of the total corneal thickness was obtained by using confocal microscopy in vivo. Confocal images were captured and digitized. The longitudinal orientation (vertical, horizontal, and oblique) and morphological characteristics of the microfolds were described and recorded. RESULTS Six eyes had folds at the central corneal flap, visible as linear distortions in the confocal images: one fold had a vertical orientation, two were horizontal, and three were oblique. The folds were visible from the epithelial basal cell layer to the stromal portion of the flap and were deeper than Bowmans layer. CONCLUSIONS Confocal microscopy allowed visualization of microfolds after LASIK. With the appropriate software, it is possible to analyze the morphological characteristics of these folds. Flap microfolds after LASIK are deeper than Bowmans layer.

A corneal diffuse neurofibroma as a manifestation of von recklinghausen disease.

Purpose. To report a case of a primary corneal diffuse neurofibroma in a patient with von Recklinghausen disease (NF-1). Methods. Case report. A physical examination and histopathology were performed. The immunohistochemical studies were performed using an avidin-biotin-peroxidase complex technique on formalin-fixed and paraffin-embedded tissue. Histologic sections from corneal tissue were incubated with primary antibodies against vimentin and S-100 protein. A complementary ultrastructural study of the same formalin-fixed and paraffin-embedded tissue was made. Results. The ophthalmologic examination revealed a yellowish-white elevated mass that involved the supratemporal cornea but not the limbus. Histologic study showed a tumor of the peripheral nerve sheath, a diffuse neurofibroma in the corneal stroma, and proliferation of spindle cells with markedly elongated nuclei. Cells comprising the tumor reacted with vimentin and S-100 protein, and the ultrastructural studies revealed myelinated nerve fibers confirming the diagnosis. Conclusion. The development of a primary diffuse neurofibroma in the cornea of patients with von Recklinghausen disease is possible. The present case supports the statement that neurofibromas arising from the peripheral nerve sheath may involve any part of the body.

Frequency and risk factors associated with dry eye in patients attending a tertiary care ophthalmology center in Mexico City.

Purpose The purpose of this study was to ascertain the frequency and risk factors of dry eye (DE) among patients attending a tertiary care ophthalmology center in Mexico. Methods Approximately 338 consecutive new patients attending a tertiary care ophthalmology center in Mexico City underwent an ocular surface examination, which included tear film break-up time, fluorescein corneal staining, Schirmer’s test, and evaluation of meibum quality. Symptoms of DE were evaluated by the Ocular Surface Disease Index and Dry Eye Questionnaire-5. Information on demographics, exposures, past medical and ocular history, and medications was also collected. Results The frequency of severe DE symptoms was found to be 43% based on the Ocular Surface Disease Index and 30% based on Dry Eye Questionnaire-5. Risk factors significantly associated with increased DE symptoms included dry mouth and gastrointestinal ulcer medications. With regard to signs, aqueous tear deficiency was a less-frequent finding (22%) in our population than evaporative deficiency (94%). Risk factors associated with aqueous tear deficiency were dry mouth and diuretic use. No risk factors were associated with evaporative deficiency. Risk factors associated with meibomian gland dysfunction included old age, male sex, arthritis, and use of an antihypertensive. The only risk factor associated with corneal staining was dry mouth. Conclusion This is the first study to demonstrate the frequency of symptomatic and clinical DE in a tertiary care ophthalmology center in Mexico. The frequency of DE ranged from 30% using a symptomatic definition to 94% using objective measures. Different risk factors were found for different aspects of DE, suggesting differing underlying pathophysiologies behind different DE subtypes.