Comparing Significant Change in Visual Fields in Ocular Hypertensive Eyes With the Ocular Hypertension Treatment Study (OHTS) Abnormality Criteria, Guided Progression Analysis (GPA) and Visual Field Index (VFI)

Abstract

Purpose: : To compare the identification of significant change from baseline normal visual fields using OHTS abnormality criteria, GPA and VFI in ocular hypertensive eyes from Diagnostic Innovations In Glaucoma Study (DIGS) and African Descent and Glaucoma Evaluation Study (ADAGES).

Methods: : Five or more (11.2+6.4, mean+SD) reliable consecutive visual fields from 149 eyes of 77 ocular hypertension (OHT) patients were included. Patients ranged from age 19.8 to 79.9 (56.3+11.8) years and had both normal optic discs by masked stereophotograph review and two normal standard Humphrey 24-2 visual fields (VF) at baseline. Patients had either highest untreated IOP >21 on at least two occasions or were currently on IOP lowering medications. In addition, central corneal thickness (CCT) was between 475 and 650 microns (579+36). Visual field progression from normal baseline using the OHTS endpoint criteria (glaucoma hemifield test of outside normal limits or pattern standard deviation (PSD) at 5% or worse on 3 fields), GPA (likely progression) and VFI (significant slope >5%) was determined.

Results: : Twenty-nine eyes progressed by at least one algorithm. The mean follow-up duration for progressed eyes was 9.8+4.7 years and for non-progressed eyes was 8.0+4.2 years. The mean+SD baseline IOPs of thirty-eight untreated patients and thirty-nine treated patients were 25.2+2.6 and 26.5+4.2 mm Hg. Baseline mean vertical cup to disc ratio was 0.43+0.16. VF mean deviation and PSD were - 0.17+1.34 and 1.69+0.43 dB, respectively. Of these 149 eyes, VFI (n=19) showed significantly more eyes as changing than did GPA (n=11, p=0.006). Nine eyes changed using OHTS abnormality criteria. To compare the agreement among the algorithms, pair-wise Kappa analyses yielded values of 0.26+0.11, (GPA/VFI), 0.07+0.09 (OHTS/VFI) and 0.36+0.14 (OHTS/GPA) for degree of agreement.

Conclusions: : Thirteen percent of the OHT eyes in this study showed significant progression in visual fields on VFI, which called more change than did OHTS or GPA. At best, the agreement among the three algorithms was only fair suggesting caution should be used when comparing results from studies using different criteria for change in visual field status.

Keywords: visual fields • perimetry