Influence of uncorrected ametropia on computer-based perimetry in patients with visual field defects and normal subjects.

Background: During perimetric testing it is well known to wear spectacles. But less is known about to what extent refractive errors affect the response time performing computer-based visual tasks.

Methods: Patients with visual field defects (VFD) (n = 6) and normal control subjects (n = 6) performed computer-based high resolution perimetry (HRP) with and without the use of spectacles. We recorded stimulus detection, response times, false hits, and fixation controls as well as contrast sensitivity with and without spectacles.

Results: Performance without spectacles resulted in decreased contrast sensitivity of control subjects (41.5%, p < 0.05) and patients with VFD (36.4%, p < 0.05) and slowed reaction times from 436.2 ms to 463.7 ms in patients (p < 0.05) and from 371.3 ms to 402.3 ms in normal subjects (nonsignificant). In patients also reduced stimulus detection from 64.0% to 58.6% (nonsignificant) and increased number of false hits from 1.7 to 2.8% (nonsignificant) occurred. However, the normal subjects showed more false hits with glasses (2.3%) than without (1.0%, nonsignificant). The number of fixation control responses was unaffected. The majority of the subjects felt subjectively better wearing eyeglasses.

Conclusion: Both in normal subjects and patients with VFD computer-based diagnostic tests should always be performed with eyeglasses to optimize visual performance.