Laser ablation and comparable techniques in ophthalmology

Ophthalmology more than any other speciality has utilised lasers for both treatment and diagnosis of many eye conditions. Helium neon lasers are used for diagnosis to accurately view fundus details and to measure blood flow in laser doppler velocimetry and as aiming beams to accurately site therapeutic laser lesions. No ophthalmic unit can function without an argon laser which is used predominantly on pigmented structures-iris, retina and choroid as well as haemoglobin within blood vessels to produce a thermal lesion. The most widespread application of the argon laser is photocoagulation of the retina in diabetic retinopathy which is the commonest cause of blindness in the middle age group. Amongst other applications it is also used to ablate neovascular subretinal membranes and to cause choroidoretinal adhesion around retinal tears. Argon green causes less incidental damage to photoreceptors and less damage to nerve fibres as there is less absorption by xanthophyll pigment at the fovea. It has superseded argon blue/green and krypton red. Diode lasers have been more recently introduced and have the advantage of being solid state, are cheap, reliable, small and portable and have considerable potential for use out in the field in third world countries