The Lang lecture 1986. The enigma of primary open-angle glaucoma.

An account is given of the Moorfields prospective surgical v medical trial in primary open angle glaucoma. The intra-ocular pressure, visual fields calculated on a percentage basis and the visual acuity were measured in 52 subjects at 3 monthly intervals for up to 18 years. Fifty per cent of the patients underwent surgery by random selection and an attempt was made to determine whether the surgical or the medical cases fared better. Even after this extended period little correlation between visual field and the level of intra-ocular pressure could be found. The results appeared to favour the possibility that surgery was of some benefit in terms of visual field whereas medical therapy was probably better for visual acuity: but in neither case was convincing proof obtained. The final conclusion was that more research is needed but in the meantime too frequent and too elaborate surveillance of open angle glaucoma is not particularly beneficial to the patients.