Faculty Bibliography

Steroid-induced IOP elevation affects a significant number of patients. It results from a decrease in outflow facility of the aqueous humor. To understand the pathophysiology of this condition a number of model systems have been created. These include ex-vivo cell and organ cultures as well as in-vivo animal models in organisms ranging from rodents to primates. These model systems can be used to investigate specific aspects of steroid-induced IOP elevation. This brief review summarizes the strengths and limitations of the various model systems and provides examples of where these systems have been successfully used to advance our understanding of steroid-induced IOP elevation.

PURPOSE: To study the effect of trypan blue on lens capsule elasticity and ease of completing a continuous curvilinear capsulorhexis (CCC) in a sheep lens model and to subsequently observe the effects of trypan blue in the surgical setting of 3 pediatric patients. SETTING: State University of New York, Downstate Medical Center, Brooklyn, New York, USA. DESIGN: Prospective case series. METHODS: Twenty-four lenses were excised from fresh sheep globes. Twelve lenses were immersed in trypan blue for 2.5 minutes, and 12 lenses were immersed in a balanced salt solution for 2.5 minutes. Ease of completion of CCC was graded, and intralenticular pressure was quantified. A pediatric cataract surgeon used trypan blue to stain the lens capsules of 3 children during cataract surgery. The surgeon noted the effects of trypan blue on capsule elasticity and on the ease of completion of the CCC. RESULTS: Lenses immersed in trypan blue had a mean score of 2.58 in ease of completion of capsulorhexis compared with the control group (1.5) (P = .031). Capsulorhexis was successfully completed in 91.7% of trypan blue cases compared with 58.3% of controls. Immersion in trypan blue decreased the intralenticular pressure by a mean of 4.5 mm Hg (P = .025). Successful capsulorhexis was completed in the 3 pediatric cases. CONCLUSION: Trypan blue improved the success rate of CCC completion in the sheep lens by decreasing lens capsule elasticity. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.