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Patients with ocular hypertension have abnormal point scotopic thresholds in the superior hemifield
R J Stirling1, P Pawson, G M Brimlow
1Department of Ophthalmology, Leeds General Infirmary, United Kingdom.
Purpose:
To compare light- and fully dark-adapted thresholds at loci within the central visual field in patients with ocular hypertension and glaucoma.
Methods:
Eighteen patients with chronic open angle glaucoma, 13 patients with ocular hypertension, and 24 age-matched normals were studied. The Humphrey automated perimeter with the standard background illumination of 31.5 apostilbs was used to determine photopic thresholds at 18 loci within 20 degrees of fixation. Fully dark-adapted thresholds were measured at the same loci after 30 minutes of dark adaptation by automatic, static campimetry.
Results:
The glaucoma group showed elevated scotopic thresholds. Scotopic defects also were found in a significantly higher proportion of patients with ocular hypertension than in normals. These scotopic defects were predominantly in the superior hemifield.
Conclusions:
Scotopic threshold campimetry may identify the subgroup of patients with ocular hypertension who progress to develop glaucomatous field loss identifiable by standard photopic and mesopic perimetry.