PAL 20D Aspherical Lens

Details :-

The silver ring on the lens holder should be held toward the patient’s eye during examination, which can ensure the right using direction and may provide for best image quality. Keep the lens centring on the patients pupil. Hold the lens far enough from the patient’s eye so that the retinal image has the same diameter with the lens. Keep the illumination sources as dark as possible to minimize reflections and image contrast. Keep the lens clean to minimize glare from the lens surface.