Reduced Central Visual Field Sensitivity in Glaucoma Patients With Normal 10-2 Visual Fields Compared to Healthy Controls

Abstract

Purpose: To determine whether changes in central visual function exist in glaucoma patients who present with abnormal peripheral visual fields, but who still have normal central visual fields based on global indices.

Methods: Twenty-three eyes were included: 11 patients with primary open-angle glaucoma (POAG) and 12 healthy controls. Patients had a clinical diagnosis of POAG, abnormal Standard Automated Perimetry (SAP) 24-2 and normal SAP 10-2 results. Controls had healthy eyes based on a complete ophthalmological examination and normal SAP 24-2 and 10-2 results. Abnormality on the 24-2 tests was defined as an “Outside Normal Limits” outcome on the Glaucoma Hemifield Test and/or a Pattern Standard Deviation (PSD) value triggered at <10% or worse. Abnormality on the 10-2 tests was defined as a PSD triggered at <5% or worse. Two-tailed t-tests were used to compare the groups on the 24-2 foveal threshold and on the following 10-2 parameters: Mean Deviation (MD), PSD, total number of abnormal Total Deviation (TD) and Pattern Deviation (PD) points (points triggered at either 5%, 2%, or 1%), and the number of TD and PD points triggered at <1%. The Levene test was used to determine whether t-tests for equal or unequal variance were performed. Alpha was set at 0.05.

Results: POAG patients were older than controls (67.3 ± 9.3 yrs; 54.1 ± 8.9 yrs; p = 0.002) and had significantly lower foveal thresholds (34.3 ± 1.9 dB; 36.9 ± 2.3 dB; p = 0.01). This may be due to the significant difference in age between the groups (foveal thresholds are not age-corrected). No significant differences were found between the groups for visual acuity and refraction. POAG patients had significantly worse MD values than controls (-1.6 ± 2.6 dB; 0.34 ± 0.9 dB; p = 0.04), higher PSD values (1.4 ± 0.1 dB; 1.1 ± 0.2 dB; p = 0.001), a higher total number of abnormal PD points (7.2 ± 2.6; 3.5 ± 3.0; p = 0.01), and a higher number of PD points triggered at <1% (1.4 ± 1.1; 0.4 ± 0.7; p = 0.02). No significant differences were found in total number of abnormal TD points (15.6 ± 24.2 dB; 0.8 ± 1.3 dB; p = 0.07) and number of TD points triggered at <1% (7.2 ± 19.5; 0.1 ± 0.3; p = 0.25).

Conclusions: Normal 10-2 results differ in POAG patients compared to normals, with evidence of subtle loss in central visual function in glaucoma patients.

Keywords: 758 visual fields • 642 perimetry