Optimization of laser interferometry for pre-surgical diagnostics Available to Purchase

The laser interferometer images two beams in the entrance pupil of the eye causing the creation of interference fringes on the retina. A critically relevant variable heretofore unaddressed is that of the intensity of the beams used to create these fringes. The laser interferometer has the potential to become the best tool for pre-surgically predicting post-surgical visual results in patients with ocular media problems. A calibrated variable neutral density attenuator was interposed between the low power HeNe laser used to create the fringes and the subject’s eye. Normally sighted subjects, determined by a full ophthalmological examination to be devoid of ocular pathology, were maintained under cyclopegia with 2% cyclopentalate hydrochloride throughout the experiment. Lenses were interposed in front of the patient’s eye to simulate various degrees of various media problems. These lenses consisted of 0 to 100% scatter (simulating conditions of cataract or corneal opacity), 0 to 60 diopters of sphere (simulating blur or image degradation), and 0 to 60 diopters of cylinder (simulating astigmatism or image distortion). Attenuation of the fringes was varied over a 4 log unit range to determine the optimal intensity for predicting laser interferometric resolution thresholds under conditions of blur, scatter, and astigmatism.