Scanning laser ophthalmoscope for retinal microphotocoagulation and

Abstract

A combination of a confocal scanning laser ophthalmoscope and external laser sources is used for microphotocoagulation or the measurement of wavefront aberrations across the pupil of the eye. An opto-mechanical linkage device allows independent positioning of the pivot point of the Maxwellian view of the scanning laser ophthalmoscope and the pivot point of non-scanning external laser beams. The same pivot point is necessary to minimize wavefront aberrations and to enable precise focussing of a therapeutic laser beam on the retina. The pivot point of an external diagnostic laser beam is systematically moved across the anatomical pupil when wavefront aberrations of the eye optics are to be measured. The retinal location of the external laser beam is determined with two synchronized detectors and digital image processing techniques. One detector is used to localize moving fiducial landmarks of the retina. Independently, a second detector is used to locate the retinal backscatter caused by the external laser beam. This backscatter produces a convolved image with the retinal conjugate aperture and not a direct image of the external laser retinal location.