OCT guided femtosecond laser treatment of vitreous floaters: A safety study

Abstract

Purpose : Visually significant vitreous floaters are associated with reduced vision and contrast sensitivity for affected patients with high impact on their quality of life. There are only limited treatment options available. In this paper we present laser safety limit calculations as well as the first animal safety study of an OCT guided femtosecond laser system for the treatment of the vitreous.

Methods : We conducted laser safety analysis of the specific application and animal model used and defined a safe operating regiment. We modified an existing OCT guided femtosecond laser system to allow treatment of the vitreous and adapted it for the use in an animal study. Overall 6 rabbits (12 eyes) received volumetric laser treatment of the vitreous using a high or normal dose of total energy delivered to the vitreous. Pre, 1 hour, 1 day and 3 day follow up measures included IOP and full eye slit lamp exam. Fundus images and fluorescence angiography were performed pre and 1d post exposure. Post mortem measures included histology and vitreous drainage experiments.

Results : We were able to treat all eyes within the geometrical target boundaries and laser safety limitations. In all eyes vitreous bubbles resembling the laser pattern were present immediately after exposure but greatly reduced to the 1hr follow up and were completely resorbed 1 day after exposure. IOP slightly increased by 4mmHg at day 1 and was normal otherwise. Fluorescence angiography and histology revealed normal and intact retina confirming the used safety parameters. Day 3 follow up slit lamp exam indicated lens posterior horizontal haze lines while post mortem histology of the lens did not show any changes. Post mortem measurements showed significant higher drainage of treated eyes compared to untreated reference samples.

Conclusions : Initial animal safety testing supported the laser safety analysis as no damage to the retina was found. The combination of an acceptable low IOP increase at 1d FU in combination of favorable vitreous drainage are good indicators that OCT guided femtosecond laser treatment of floaters has the potential to provide a non-invasive and safe treatment option for vitreous floaters. Long term studies need to be performed to ensure no other effects are generated.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.