Zoom Slit Lamp Adapter for Ophthalmological Green Laser

Abstract

The present article describes the development of a Zoom Slit Lamp Adapter (SLA) coupled in a laser cavity for ophthalmologic applications. The coupling system is composed by a collimation doublet that focuses the green laser beam from the cavity to a 105μm optical fiber core. The coupling efficiency reached was around 90-95%. The other side of the fiber is aligned by a micro-mechanic centralizer that guides the beam to the SLA optical system. This system is responsible for the variation of the spot magnification and keeps the focus in the same position for the entire range of zoom adjustment.

The optical system is composed of 5 lenses coupled in a mechanical rotating support. This support consists of a cam, which composed of two different curves. Theses curves are responsible by the movement of zoom SLA optical system. The distance between the lenses changes obeying a interpolated equation composed by 484 points projected to change the spot size continuously from 50μm to 600μm, with a maximum couple efficiency of 75%. The SLA is widely used in a several ophthalmological protocols, such as, proliferative and nonproliferative diabetic retinopathy, retinal detachment, retinal tears, retinal hemorrhage, vein occlusion, glaucoma and macular edema [1]. The delivery beam is composed by a micro-manipulator system that amplifies the user sensitivity, reflecting in a more accurate laser application.