Cataract model for resident phacoemulsification teaching: 10% buffered formalin induction oflenticular sclerosis in enucleated porcine eyes

Abstract

Abstract: : Purpose:There is a steep learning curve for the development of the necessary surgical skills for intraocular surgery including phacoemulsification. Laboratory models provide a safe means of technique mastery. Commerically available artificial eyes allow for reasonable phacoemulsification simulation, yet are limited by expense. We sought to develop an inexpensive method of creating cataracts with the added benefit of controlling the degree of opacification. Methods:15 freshly enucleated porcine eyes (<24 hours from harvest) were obtained from a commercial supplier. 0.1–0.2 cc of 10% buffered formalin was then injected using a 27 guage needle via a pars plana approach with direct visualization of the needle tip passing within the lens material. In the first eye, a single neeedle pass was used in an attempt to perform a sub–anterior capsule injection. This did not result in any appreciable sclerosis after 120 minutes. Following this, we modified our technique to include multiple passes for greater distribution of the sclerosing agent throught the lens material. Results:Table one presents the observed relationship between time after injection of 10% buffered formalin and the degree of lenticular opacification. Significant sclerosis was found after at least 30 minutes post–injection. Complete sclerosis of the lens material was not observed until at least 80–90 minutes post–injection. Conclusions:The slowly evolving sclerosis of lens material reported in this study suggests that 10% buffered formalin may be an option when the creation of model cataracts with varied degrees of density is desirable. This is in contrast to other reported models including microwave heating which provide a dense effect in 10 seconds of treatment. Injection of sclerosing agents such as formalin is limited by diffusion within the lens material, yet does provide a usuable model cataract. Table 1: Post–injection time and degree of lenticular haze 

Keywords: training/teaching cataract surgery • cataract • learning