Ramón Naranjo-Tackman

A comparative confocal microscopy analysis after LASIK with the IntraLase femtosecond laser vs Hansatome microkeratome.

PURPOSE To evaluate and compare confocal microscopy findings between a femtosecond laser and a mechanical microkeratome. METHODS Eighteen eyes of nine patients underwent LASIK. Corneal flaps were created with the femtosecond laser in the right eyes and a mechanical microkeratome in the left eyes. The corneal flap interface was analyzed in all eyes with a confocal microscope at 1 week and 1 month postoperatively. RESULTS All eyes showed small reflective particles at the corneal flap interface. The mean number of reflective particles was not statistically significantly different at 1 week (P = .078) and 1 month (P = .28) using a femtosecond laser and a mechanical microkeratome. CONCLUSIONS Confocal microscopy findings at the corneal flap interface showed a similar number of particles using both systems.

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.

Traumatic Flap Dislocation 4 Years After LASIK Due to Air Bag Injury

PURPOSE To report a patient who developed corneal flap dislocation following air bag injury 48 months after LASIK. METHODS Evaluation by slit-lamp microscopy and fluorescein angiography. RESULTS A 29-year-old man was treated after air bag injury that occurred 48 months after LASIK. Examination revealed corneal flap dislocation, with severe folds and flap edema. Preoperative visual acuity was finger counting at 1 m. Visual acuity was 20/400 24 hours after repositioning the corneal flap. Retinal angiography revealed Berlin macular edema, which was injected with periocular steroids. Five days after injection, visual acuity remained 20/400, but improved to 20/40 1 month after injection. CONCLUSIONS Significant trauma can dislocate a corneal flap many months after surgery.

Pneumococcal keratitis at the flap interface after laser in situ keratomileusis

A 28-year-old woman had uneventful laser in situ keratomileusis in the right eye. Six days postoperatively, she reported ocular pain and a large corneal stromal infiltrate was observed at the flap interface. A second surgery including lifting and excising the flap and scraping the stromal bed was performed. Topical antibiotics were prescribed. A bacterial culture revealed Streptococcus pneumoniae. The keratitis responded well to topical vancomycin. Twelve days after the second surgery, the stromal infiltrate had regressed, the hypopyon had resolved, and visual acuity was hand movements at 0.5 m.

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.

Frozen cultured sheets of epidermal keratinocytes in reepithelialization and repair of the cornea after photorefractive keratectomy.

Purpose: To determine whether frozen cultured sheets of human allogeneic epidermal keratinocytes (CEAK) improved wound repair after experimental corneal ablation by photorefractive keratectomy (PRK). Setting: Hospital “Luis Sanchez Bulnes” de la Asociación para Evitar la Ceguera en Mexico, I.A.P, and Department of Cell Biology, CINVESTAV‐IPN, Mexico City, Mexico. Methods: Transepithelial PRK was performed in the right eye of male albino rabbits to obtain a 112 &mgr;m deep and 6.0 mm diameter ablation zone. In 17 eyes, the ablations were covered with frozen CEAK; in 11 eyes, the ablations were covered with a disposable contact lens without the cultured sheets; and in the control group (13 eyes), the ablations were not covered. Subepithelial fibrosis and reepithelialization of the ablated zone were evaluated in serial paraffin‐embedded tissue sections from all wounds. Results: Treatment with CEAK reduced fibroblast proliferation and the inflammatory response beneath the ablated zone and produced better organization of the newly formed epithelium by eliminating significant hyperplasia or discontinuities in the periodic acid Shiff‐stained basement membrane. It also led to accelerated reepithelialization. Conclusions: The use of frozen CEAK as a biologically active wound dressing improved tissue repair at 1 month in corneas ablated by transepithelial PRK in the male albino rabbit model. Treatment with CEAK could improve the outcome of PRK in humans.

Hallazgos tempranos por microscopia confocal en cross-linking

OBJECTIVE To determine the effects of in vivo cross-linking treatment of the cornea. METHODS Eighteen eyes of eighteen keratoconus patients underwent cross-linking treatment using a 0.1% riboflavin solution and ultraviolet A radiation at 370 nm at 3 mW/cm² for 30 minutes. In vivo confocal microscopy was performed before, and at 1 week and 1 month after treatment. RESULTS At 1 week after treatment, keratocyte activation and collagen fiber organization showed as hyper-reflective structures and were observed from the first sub-epithelial image to a corneal stromal depth of 275.1 ± 85.9 μm. At 1 month after treatment, activated keratocytes and fiber organization were also observed from the first sub-epithelial image to a corneal stromal depth of 324.9 ± 66.0 μm. The deepest hyper-reflective structures at 1 month showed as thick, linear-shaped hyper-reflective structures. CONCLUSION In vivo confocal microscopy in humans showed corneal stromal changes at 1 week and 1 month after cross-linking treatment, in some cases at depths in excess of 300 μm.

Epi-LASIK: A Confocal Microscopy Analysis of the Corneal Epithelium and Anterior Stroma

BACKGROUND AND OBJECTIVE To evaluate the confocal microscopy findings at the corneal epithelium and anterior stroma after epi-LASIK. PATIENTS AND METHODS Twelve eyes of 12 patients underwent epi-LASIK. A central scan of the total corneal thickness was taken with the confocal microscope before and at 2 weeks and 1 month after surgery. Corneal epithelial thickness was measured and the anterior stroma morphology was also analyzed. RESULTS Mean epithelial thickness was 46.5 ± 5.5 μm before surgery. It had decreased by 23.4% (35.6 ± 5.6 μm) at 2 weeks and by 22.1% (36.2 ± 5 μm) at 1 month postoperatively, compared with the preoperative measurement. The change in thickness was statistically significant. The anterior stroma showed keratocyte activation at 2 weeks and 1 month after surgery. CONCLUSION Corneal epithelial thickness was decreased up to 1 month after surgery. The stromal ablation zone showed keratocyte activation in both postoperative measurements.