Relating Standardized Automated Perimetry Performed With Stimulus Sizes III and V in Eyes With Field Loss Due to Glaucoma and NAION.

Purpose

Standard automated perimetry (SAP) visual field (VF) results are more repeatable using Goldmann stimulus size V (size V) in eyes with moderate/severe deficits due to glaucoma. There are few reports relating VFs using stimulus size V and III, typically used in the clinic for glaucoma, and none for non-arteritic anterior ischemic optic neuropathy (NAION). We hypothesized that we could compare and relate the VFs with both stimuli for glaucoma and NAION.

Methods

We utilized 1992 same-day pairs of size III and size V SAP VFs using the 24-2 strategy for eyes with glaucoma or NAION. We explored the optimal threshold to censor the raw sensitivities, prior to calculating age-standardized total deviations (TDs). We determined the mean and standard deviation of the differences among all TD pairs. We computed a line of best fit to determine closeness to the line of unity.

Results

The ideal censoring conversion threshold was 21 decibel (dB) for size III and 24 dB for size V. The difference between size V and size III censored (0.0 ± 1.9 dB) and uncensored (0.4 ± 2.6 dB) TD pairings highly correlate with each other (r2 = 0.70, P < 0.001). The line of best fit from these pairings has a slope of 0.92, which is close to that of the line of unity (m = 1).

Conclusions

Censoring plus age correction is a valid method of comparison between size III and size V SAP VFs with moderate to severe VF loss due to optic nerve disorders.

Translational relevance: Size III and size V TDs are comparable in clinical practice.