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Editor,—The Royal College of Optometrists guidelines 19971 suggest routine eye tests include “visual field assessment on all relevant patients, especially those at risk of glaucoma (this includes all patients over age 40 years)”. It has been our clinical impression that many optometrists now routinely perform automated perimetry on all patients over the age of 40 years, identifying more false positives than treatable pathology.
We prospectively studied all asymptomatic patients referred from an optometrist with abnormal automated perimetry but normal ocular examination. Patients attending for glaucoma screening were excluded.
Eleven such patients were referred to this consultant’s service over a 16 month period including two under 40 years old. All had corrected acuities of 6/9 or better bilaterally, had not reported any ocular symptoms, and had normal intraocular pressures and funduscopy according to the optometrist.
Suprathreshold perimetry was used in 10 cases (one not obtainable) with the optometrist attempting interpretation in only four—three described as bitemporal loss suggestive of chiasmal pathology (one was actually binasal) and one as an arcuate scotoma on the grey scale where only one spot had been missed.
Four patients were considered to have normal repeat visual fields, three had bitemporal field defects consistent with tilted optic discs but were followed up for a period to exclude progression, one had an old occipital infarct with a homonymous quadrantanopia, and one patient had a walled off schisis detachment. Bilateral field constriction was presumed functional in a patient with a normal magnetic resonance scan and electrophysiology—an optometrist had referred her 4 years previously with similar findings. The remaining patient had suffered blurred vision and sensory disturbance 11 years before and was found to have bilateral field constriction and enlarged blind spots—the only identifiable pathology has been a parietal angioma which does not explain the pattern of field loss.
No serious, treatable pathology was identified in these patients and none was found to have glaucoma. Our findings do not support the routine use of automated perimetry in patients under the age of 60 years who have no symptoms and signs of pathology or risk factors for glaucoma. We propose that the Royal College of Optometrists guidelines be revised to recommend that automated perimetry be reserved for those with clinical evidence of ocular pathology and those over the age of 60 or with other risk factors for glaucoma.