Evaluation of effect of modified housing on fogging of reusable wide angle panoramic contact lens during vitreoretinal surgery

ABSTRACT

Purpose: To evaluate the effectiveness of modified housing on fogging of reusable wide angle contact lens during vitreoretinal surgery Methods: Wide angle contact lens provides panoramic view of retina and enables successful vitreoretinal surgery in complex retinal detachments through improved visualization of vitreoretinal periphery upto and beyond ora serrata. However frequent steam sterilization erodes the glue that holds lens elements, allows fogging due to migration of steam in between lens elements and result in poor visualization of the fundus. In this study, we altered the housing and evaluated its effectiveness. Modified housing has two modes;open mode during sterilization and closed mode after completion of sterilization (Figs 1&2). The lens system has two lens groups. The first group has a concave posterior surface [Radius of curvature (ROC) = 7.8 mm], for placement on the patient's cornea. This group acts to direct light rays originating from the posterior chamber towards the second lens group II for focusing. The group I lens system collimates the light rays. Group II is located in a spaced-apart relationship with respect to first lens group I. This allows an air space between them. The group II focuses the light rays and provides panoramic visualization of retina. Housing that holds the two lens systems has a rotational window that is open during steam sterilization and closed during surgery Results: The lens system provided real and inverted panoramic image of the fundus. The lens system is configured to minimize chromatic aberration and provide improved image as compared to the other lens systems. It provides 160 degrees of fundus view during static viewing and 170 degrees during dynamic view with excellent depth of focus. Modified housing has facilitated fog free visualization of retina during surgery while allowing effective steam sterilization compliant with standard operating room regulations. Conclusions: This modified wide angle contact lens provides a real inverted panoramic fog free view of the retina and allow repeated usage without deterioration of image and prolonged the life of wide angle contact lens system. It has added significance in covid era, as stringent sterilization is essential for prevention of disease.