Preperimetric glaucoma study 2: The relationship between optic nerve head blood flow and visual field progression in preperimetric glaucoma

Abstract

Purpose : We previously reported that optic nerve head blood (ONH) flow, as measured with laser speckle flowgraphy (LSFG), is significantly reduced in preperimetric glaucoma (PPG) (Shiga et al. 2015 in press). The purpose of this study was to investigate the relationship between LSFG-measured ONH hemodynamics and visual field progression in eyes with PPG that were undergoing treatment with topical prostaglandin analogues.

Methods : This prospective study comprised 93 eyes of 93 PPG patients (53.6 ± 1.9 years old). All patients were followed for at least 16 months and underwent at least 5 visual field examinations. ONH blood flow was assessed according to tissue-area mean blur rate (MBR_T), an index of capillary blood flow derived from LSFG. Circumpapillary retinal nerve fiber layer thickness (cpRNFLT) was measured with spectral-domain OCT. Visual field parameters were measured with the 24-2 SITA standard program of the Humphrey Field Analyzer. Total deviation (TD) slope was measured in each sector of the Garway-Heath map, which relates the anatomy of the ONH to the visual field. Finally, we classified subjects whose TD slope was in the first quartile as progressive and other subjects as non-progressive. We then compared baseline clinical characteristics in the two groups.

Results : We found that the TD slope in the upper temporal peripheral sector was significantly reduced in the subjects overall (-0.38 ± 1.43 dB/y, p = 0.001). Furthermore, MBR_T was significantly lower in this sector in the progressive group (10.23 ± 1.77 AU; 24 eyes of 24 subjects) than in the non-progressive group (12.02 ± 2.26 AU, p = 0.001; 69 eyes of 69 subjects). Otherwise, there were no significant differences in age, refractive error, untreated intraocular pressure, vertical cup/disc ratio, or cpRNFLT between the groups.

Conclusions : These data suggest that reduced ONH blood flow is associated with upper visual field loss progression in PPG eyes.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.