Descemet membrane endothelial keratoplasty donor preparation: navigating challenges and improving efficiency.

PURPOSE: The aim of this study was to describe the challenges in Descemet membrane endothelial keratoplasty (DMEK) donor preparations and provide new strategies to achieve success. METHODS: A series of 263 consecutive DMEK preparation attempts by a novice surgeon during a corneal fellowship are described. In all cases, the Descemet membrane (DM) and the endothelium were peeled off from the donor cornea while it was submerged in corneal storage medium. RESULTS: The success rate of preparing DMEK tissue was 99%. Three donor preparations of 263 (1.1%) could not be completed successfully because spots of strong adherence between the DM and the stroma caused multiple horseshoe-shaped tears (HST) to form in the DM. Lamellar splitting of the DM ("partial thickness HST") preceded the formation of most HSTs. At least 1 HST occurred in 13% of donor preparations. In donor pairs (right and left corneas of 1 individual donor), if 1 cornea had any HSTs, there was a 60% chance that the contralateral cornea would have at least 1 HST. If 1 cornea had multiple HSTs, there was an 80% chance that the contralateral cornea would have at least 1 HST. Noting this trend, 3 donor corneas were returned to the eye bank unopened for other uses after their mates had multiple HSTs. CONCLUSIONS: With appropriate techniques, DMEK donor preparation can be highly successful, even for a novice surgeon. When a donor develops multiple HSTs, we recommend not using the mate for DMEK because of a higher risk of encountering a preparation difficulty.

Photoactivated riboflavin treatment of infectious keratitis using collagen cross-linking technology.

PURPOSE: To evaluate riboflavin/ultraviolet-A (UVA) as an adjunct treatment for infectious keratitis. METHODS: This prospective, dual-center, interventional case series included cases of infectious keratitis that were treated by instilling riboflavin 0.1% solution for 30 minutes to saturate the cornea, followed by exposure to 365-nm UVA light (3 mW/cm(2)) for 15 to 45 minutes, with continued instillation of riboflavin. Eyes continued on standard antibiotic treatment. The primary outcome measures were the times to resolution of the infiltrate and the epithelial defect. RESULTS: Forty patients aged 14 to 86 years were enrolled. Seven (18%) eyes had a previous keratoplasty. Bacterial species were identified in 24 eyes, fungal in 7, protozoan in 2, viral in 1, and no organism in 6. The maximum infiltrate diameter ranged from 1 to 12 mm and the epithelial defect diameter was 0 to 8 mm before treatment. In 6 cases (2 bacterial, 3 fungal, and 1 without growth), the keratitis did not resolve successfully and the eye received a penetrating keratoplasty (PK). In 1 eye with prior PK, the infection resolved following treatment, but a regraft was required to address perforation of the PK incision. CONCLUSIONS: Riboflavin/UVA should be avoided in eyes with prior herpes simplex but otherwise posed no obvious safety risk in this series and appeared to be most effective when the infection depth was limited. The success rate was higher for bacterial infections than fungal infections. Randomized studies against antibiotics alone are needed to further evaluate efficacy.

Keratoconus onset after age 50.

PURPOSE: To describe the sudden clinical manifestations of keratoconus in a 51-year-old woman. METHODS: The patient had stable annual refractions for several years with 0.50 diopters (D) astigmatism in each eye and later developed 2.00 and 6.00 D of astigmatism in the right and left eyes, respectively. RESULTS: Topography and tomography showed definite keratoconus in the left eye and possible keratoconus in the right eye. The patient had no known family history of keratoconus and no known connective tissue disease other than fibromyalgia. She wore soft contacts for 20 years and had allergies, but did not rub her eyes. The patient was treated with corneal collagen cross-linking (CXL). CONCLUSIONS: Although rare, ectatic changes can occur later in life without prior surgery or trauma. The patient has shown early signs of improvement with CXL despite her age.