How useful is visual field testing in an African glaucoma clinic?

Abstract

Mpopi Lenake,1,2 Colin Cook,1,2 Hamzah Mustak,1,2 Nagib Du Toit1,2 1Division of Ophthalmology, Department of Surgery, Groote Schuur Hospital, Cape Town, South Africa; 2The University of Cape Town, Cape Town, South Africa Purpose: To investigate the usefulness of visual field testing in the diagnosis and subsequent management of glaucoma in a specialist glaucoma clinic at Groote Schuur Hospital, Cape Town, South Africa.Methods: A retrospective case note review of 344 patients who attended the glaucoma clinic between January and June 2010.Results: The study population consisted of 201 (58%) females and 143 (42%) males. The diagnoses included 207 (60%) cases with primary open-angle glaucoma, 58 (17%) cases with chronic angle closure glaucoma, 46 (13%) cases with secondary glaucoma, 17 (5%) cases with normal pressure glaucoma, ten (3%) cases with ocular hypertension, and six (2%) glaucoma suspects. Visual field testing contributed to the diagnosis of glaucoma in only 34 (10%) cases. A total number of 2,604 fields were performed. Of these fields, 1,931 (74%) were reliable. A baseline was reached in only 141 (53%) patients. There was evidence of field progression in only 24 (9%) cases. Changes to glaucoma treatment were based on inadequate control of intraocular pressure alone in 309 (90%) patients. Visual field progression contributed to changes in treatment in only 15 (4%) cases. Conclusion: Visual fields are not used in the diagnosis and management of glaucoma in the majority of patients in our clinic. Patients present with advanced disease, which is easily diagnosed without the use of visual fields. Progression of fields seldom contributes to monitoring and intraocular pressure is mainly used to monitor the adequacy of treatment. Keywords: Humphrey visual fields, reliability, diagnosis, progression