Longitudinal Measurement of Optic Disc Vessel Density to Detect Glaucoma Progression in High Myopia.

PURPOSE

To investigate the relationship between optic disc vessel density (ODVD) reduction and visual field (VF) progression in highly myopic glaucomatous eyes.

DESIGN

Retrospective observational case series.

PARTICIPANTS

One hundred and eighteen primary open-angle glaucoma (POAG) eyes with high myopia (axial length [AXL] ≥ 26.5 mm or spherical equivalent [SE] ≤ -6 D) and 118 age- and VF-severity-matched POAG eyes without high myopia (AXL < 26.0 mm and SE > -6 D).

METHODS

All participants underwent ≥ 5 consecutive VF tests, optical coherence tomography (OCT), and OCT angiography (OCTA) over 4.1 years. ODVD was calculated as the pixel ratio of vessels in the temporal optic disc area on enface OCTA images.

MAIN OUTCOME MEASURES

The association between VF progression and the rate of ODVD change after adjusting for possible influencing factors, including retinal nerve fiber layer (RNFL) thinning rate.

RESULTS

In highly myopic eyes, VF progressors (n = 41) exhibited a significantly faster rate of global ODVD reduction compared to non-progressors (n = 77) (-3.96 ± 2.15 %/yr vs. -1.68 ± 2.37 %/yr; P < 0.001). In highly myopic eyes, younger age (odds ratio [OR] = 1.09 per 1 yr younger; P = 0.002), a higher prevalence of optic disc hemorrhage (OR = 6.76; P = 0.002), thinner RFNL at baseline (OR = 1.04 per 1 ㎛ thinner; P = 0.024), and a faster rate of global ODVD change (OR = 1.63 per 1 %/yr faster; P < 0.001) were associated with VF progression in multivariable regression. Conversely, the rate of average RNFL thinning (P > 0.05) showed no significant association with VF progression in highly myopic eyes. For eyes without high myopia, significant associations with VF progression were found for both a faster rate of average RNFL thinning (OR = 2.43 per 1 ㎛/yr faster; P = 0.006) and ODVD change (OR =1.42 per 1 %/yr faster; P = 0.004) in the multivariable regression.

CONCLUSIONS

In highly myopic glaucomatous eyes, progressive ODVD reduction was associated with VF progression, while RNFL thinning was not. This indicates that monitoring of optic disc microvasculature may effectively detect glaucoma progression in high myopia.