Anita Shukla

Wound anatomy after type 1 Boston KPro using oversized back plates.

Purpose: To compare the anatomy of the graft–host junction and anterior chamber angle after Boston Keratoprosthesis (KPro) placement using oversized (9.5-mm) and standard (8.5-mm) back plates. Methods: Six patients with 9.5-mm titanium back plates and 10 patients with 8.5-mm titanium back plates were imaged by anterior segment optical coherence tomography 6 to 12 months after KPro placement. The location of the graft–host junction in relation to the back plate, the corneal thickness at the graft–host junction, and the anterior chamber angle were assessed. The clinical outcomes and incidence of retroprosthetic membrane (RPM) formation in this cohort were retrospectively evaluated. Results: The oversized back plates completely covered the graft–host junction in all quadrants, allowing the complete apposition of the posterior surface of the carrier graft with the host cornea, with decreased graft–host junction wound thickness. The standard back plates covered the posterior aspect of the carrier graft but not the graft–host junction or the host cornea, resulting in a significantly thicker graft–host junction. None of the patients with larger back plates developed a significant RPM during a 12-month follow-up period. One patient with a larger back plate developed a corneal melt at the KPro stem as a result of chronic exposure. Conclusions: Oversized KPro back plates effectively cover the graft–host junction without any adverse effects on angle anatomy or wound healing. This may be a strategy to provide better wound apposition, reduce RPM formation, and reduce angle closure from iris synechiae to the wound.

Corneal alkali burns: a review of the literature and proposed protocol for evaluation and treatment.

Chemical injuries to the eye may rapidly cause extensive damage to the entire anterior segment, resulting in permanent vision loss. Most victims tend to be young and male; and exposures occur in industrial accidents, at home, or during an assault. The most common causes of alkali injury are ammonia, lye, potassium hydroxide, magnesium hydroxide, and lime. Ammonia is the most damaging, but fortunately, lye is the most common. Upon presentation to the emergency room, initial treatment is irrigation with copious amounts of saline or cederroth solution, which has been shown to be more effective. Once pH has returned to and is maintained at a normal level, the treatment protocol is less defined. Standardizing treatment may improve patient outcomes, and decrease patient morbidity; and would also have the benefit of allowing for a systematic review of treatment efficacy. In an effort to arrive at a standardization of treatment for patients with alkali burns who are evaluated and treated in the Massachusetts Eye and Ear emergency room, we present a review of the scientific and clinical literature.

Low-Cost and Readily Available Tissue Carriers for the Boston Keratoprosthesis: A Review of Possibilities

The Boston keratoprosthesis (B-KPro), currently the most commonly used artificial cornea worldwide, can provide rapid visual rehabilitation for eyes with severe corneal opacities not suitable for standard corneal transplantation. However, the B-KPro presently needs a corneal graft as a tissue carrier. Although corneal allograft tissue is readily available in the United States and other developed countries with established eye banks, the worldwide need vastly exceeds supply. Therefore, a simple, safe, and inexpensive alternative to corneal allografts is desirable for the developing world. We are currently exploring reasonable alternative options such as corneal autografts, xenografts, noncorneal autologous tissues, and laboratory-made tissue constructs, as well as modifications to corneal allografts, such as deep-freezing, glycerol-dehydration, gamma irradiation, and cross-linking. These alternative tissue carriers for the B-KPro are discussed with special regard to safety, practicality, and cost for the developing world.

Confocal Microscopy of Corneal Dystrophies

In vivo confocal microscopy (IVCM) of the cornea is becoming an indispensable tool in the cellular study of corneal physiology and disease. This technique offers non-invasive imaging of the living cornea with images comparable to that of ex vivo histology. The ability to provide high-resolution images of all layers in the living cornea has resulted in new discoveries of corneal pathology at the cellular level. The IVCM analysis of corneal dystrophies is of importance to clinicians, as current methods of diagnosis involve slit-lamp characteristics, genetic analysis, and invasive biopsy. IVCM is helpful in evaluating the morphological characteristics of corneal dystrophies at the histological level and may be helpful in diagnosis, determination of progression, and understanding the pathophysiology of disease. The purpose of this review is to describe the principles, applications, and clinical correlation of IVCM in the study of corneal dystrophies.

Ex Vivo Study of Transepithelial Corneal Cross-linking

PURPOSE To perform in vitro assessment of different techniques of transepithelial corneal cross-linking (CXL) and to compare the results to deepithelialized CXL. METHODS Transepithelial CXL was performed after pre-treatment with or without penetration enhancers (gum cellulose, 0.44% sodium chloride, and 0.01% benzalkonium chloride) for 15 or 60 minutes. Deepithelialized corneas underwent CXL after pretreatment with riboflavin for 15 minutes, according to the Dresden protocol. All corneas were incubated in 0.3% collagenase A solution and the time to total dissolution was measured. Corneas were also imaged with confocal microscopy to evaluate the corneal epithelium, subbasal nerve plexus, and depth of stromal keratocyte nuclei as a means of measuring the depth of collagen CXL. RESULTS Deepithelialized CXL corneas with 15 minutes of pretreatment dissolved after 15.4 ± 3.1 hours, significantly longer (P = .001) than deepithelialized untreated corneas (8.5 ± 0.6 hours). Transepithelial CXL corneas with 15 minutes of pretreatment with or without penetration enhancers dissolved after 8.3 ± 2.1 and 7.4 ± 1.6 hours, respectively. A longer pretreatment of 60 minutes with penetration enhancers resulted in greater resistance to degradation of the transepithelial CXL corneas (14.6 ± 2.2 hours), which was similar to deepithelialized CXL corneas. The results of the biological assay correlated well with the imaging results obtained by confocal microscopy. CONCLUSIONS Corneas treated by transepithelial CXL with an extended pretreatment time of 60 minutes and penetration enhancers exhibited similar characteristics as corneas treated by the deepithelialized CXL approach. By confocal imaging, the transepithelial approach with extended pretreatment time demonstrated evidence of epithelial damage, which may have improved the treatment effect of this group. [J Refract Surg. 2017;33(3):171-177.].