Study of the contralateral eye in patients with glaucoma and a unilateral perimetric defect

To study the unaffected fellow eye in patients with glaucoma and unilateral visual field defect, using conventional automated achromatic perimetry, blue-yellow short-wavelength automated perimetry (SWAP), and a nerve fiber layer analyzer (GDx; Laser Diagnostic Technologies, San Diego, CA).

Eighteen patients in whom a unilateral visual field defect was detected on conventional computerized threshold perimetry were selected. The contralateral eyes of these patients were studied with normal conventional threshold perimetry using blue-yellow perimetry and also were studied with the nerve fiber layer analyzer. Also, 18 eyes of 18 sex- and age- (+/-3 years) matched persons without glaucoma were selected as a control group.

Of the 18 contralateral eyes, seven (38.8%) showed a visual field defect on blue-yellow conventional perimetry, and 10 (55.5%) showed a defect of the nerve fiber layer when evaluated with the nerve fiber analyzer. Of the 10 eyes with abnormal visual fields on the nerve fiber analyzer, six (60.0%) also showed a defect on blue-yellow perimetry. In the control group, no eyes showed visual field defect on SWAP, but three eyes (16.6% false positive rate) showed a visual field defect on the nerve fiber layer analyzer.

These findings suggest that what appeared to be unilateral visual field defects may in fact have been bilateral in at least 33.3% of our patients (n = 6) for whom there was agreement between results of SWAP and the nerve fiber layer analyzer.