Combination lens system for retinal photocoagulator laser system

摘要

A retinal photocoagulator has means (12) for generating a beam of laser radiation and means (18,20,24) for delivering the laser beam to the surface of the retina. The delivery means includes a lens system (20) for varying the spot size of the beam at the surface of the retina which is operable in two alternate modes over a given range of spot sizes, wherein one of the modes varies the size of the spot while maintaining the beam in a focused condition at the retina, and wherein the other mode varies the size of the spot at the retina by altering the focal point.