Background: The purpose of this study was to compare retinal sensitivities in normal individuals obtained using the Swedish Interactive Threshold Algorithm Standard (SITA-S) on the Humphrey field analyzer with those obtained using the Dynamic strategy on the Octopus.
Methods: Prior to visual field examinations, the background luminance, stimulus size, and exposure time with the Octopus 101 were conformed to the Humphrey field analyzer II settings. Volunteers over 20 years of age without apparent ophthalmic abnormalities were examined with the SITA-S central 30-2 program followed by the Dynamic 32 program. Eye with corrected visual acuity ≥ 0.8, refraction ≥ -6.0 diopters, and fields with satisfactory levels of reliability in SITA-S and Dynamic were selected.
Results: Sixty-seven eyes from 67 normal individuals of mean age 51.3 ± 16.3 (range 22-76) years satisfied the selection criteria and were analyzed. Mean retinal sensitivity was significantly (P < 0.0001) higher with SITA-S (29.0 ± 2.4 dB) than with Dynamic (26.8 ± 2.1 dB). Changes in retinal sensitivity with increasing age were significantly (P = 0.0003) greater with Dynamic (-0.09 ± 0.04 dB/year; 95% confidence interval [CI] -0.10 to -0.08 dB/year) than with SITA-S (-0.07 ± 0.04 dB/year, 95% CI -0.08 to -0.06 dB/year). When classifying the visual field into three areas (central, mid-peripheral, and peripheral), retinal sensitivities with SITA-S were significantly higher in all areas than with Dynamic (P < 0.0001 for all three areas).
Conclusion: Differences in Dynamic and SITA-S strategies may contribute to the differences in retinal sensitivities observed in normal individuals.
Keywords: Humphrey field analyzer; Octopus perimeter; Swedish Interactive Threshold Algorithm Standard; dynamic; frequency-of-seeing curve; time-saving strategy.