Alignment of eye and slitlamp beam.
D000368:Aged; D000867:Anterior Chamber; D005128:Eye Diseases / Q000175:diagnosis; D005901:Glaucoma / Q000175:diagnosis; D006801:Humans; D008722:Methods; D009885:Ophthalmology / Q000295:instrumentation*; D010781:Photography / Q000295:instrumentation*