What effect does laser photocoagulation have on driving visual fields in diabetics?

Although laser panretinal photocoagulation (PRP) for proliferative diabetic retinopathy is known to cause peripheral field constriction, the risks of failing the UK driving field test following treatment are currently unclear as the small number of previous studies have conflicting results. Following PRP using only argon laser with a 500 microns spot size, both uniocular and binocular Esterman visual fields from 60 diabetic patients were assessed by the Chairman of the Visual Standards Sub-Committee of the Royal College of Ophthalmologists. Forty-two per cent of uniocular fields from treated eyes failed. Twelve per cent of binocular fields from those having bilateral PRP failed. Type II diabetes was associated with a significant increase in the risk of failure. Although there is a high risk of failure in any given treated eye, 88% of diabetics will pass a binocular field test, even if both eyes are treated.