Progressive retinal nerve fibre layer thinning and choroidal microvasculature dropout at the location of disc haemorrhage in glaucoma

Abstract

<jats:sec id="s1"><jats:title>Background/Aims</jats:title><jats:p>To investigate whether parapapillary choroidal microvasculature dropout (MvD) is associated with progressive retinal nerve fibre layer (RNFL) thinning in eyes with primary open-angle glaucoma (POAG) and disc haemorrhage (DH).</jats:p></jats:sec><jats:sec id="s2"><jats:title>Methods</jats:title><jats:p>Parapapillary microvasculature was evaluated by swept-source optical coherence tomography (OCT) angiography (OCTA) in 50 eyes with POAG and DH, 1 year before, at the time of and 1 year after the detection of DH. MvD was defined as an area in the parapapillary deep layer of focal sectoral dropout with no visible microvascular network. Progressive changes in OCT RNFL thickness were compared in groups of eyes with and without MvD.</jats:p></jats:sec><jats:sec id="s3"><jats:title>Results</jats:title><jats:p>Cumulative prevalence of MvD was 76.0% (38 eyes) at 1 year after detection of DH. All MvDs were detected in the same sectoral locations as DH. In eyes with MvD, global RNFL thickness and sectoral RNFL thickness at the location of DH were significantly reduced, both from 1 year before to the time of DH detection (both p&lt;0.001) and from DH detection to 1 year later (both p&lt;0.001). In eyes without MvD, however, the reductions in global (p=0.011) and sectoral (p=0.007) RNFL thickness were significant only from DH detection to 1 year later.</jats:p></jats:sec><jats:sec id="s4"><jats:title>Conclusion</jats:title><jats:p>In eyes with POAG, RNFL thinning was spatially consistent and progressive at the location of MvD accompanied by subsequent DH and continued to progress after the occurrence of DH. When DH was not accompanied by MvD, progressive RNFL thinning was more likely to occur after the detection of DH.</jats:p></jats:sec>

Comparative Topographical Analysis of Choroidal Microvascular Dropout Between Glaucoma and Nonarteritic Anterior Ischemic Optic Neuropathy

“…Figure 2 C and Table 2 show the strong correlation between the angular width and location of the MvD, RNFL defect, and βPPA–RNFL defect superimposition in the entire study group (all P < 0.001), in concert with previous reports. 9 , 13 , 14 Notably, the strength of the correlation was consistently higher in the βPPA–RNFL defect superimposition than in the RNFL defect alone; in NAION, the correlation between the angular width of MvD and RNFL defects was insignificant ( P = 0.090), while the βPPA–RNFL defect superimposition successfully demonstrated a significant relationship ( P = 0.016).…”

“…Most of all, the spatial correspondence between RNFL defect and MvD in many studies was interpreted to indicate that MvD may be a finding associated with, and as a result of, the RNFL defect. 9 , 13 , 14 The proportional enlargement of MvD with glaucoma progression also indicates that MvD may not precede the chronic progressive damage in glaucoma. 4 , 5 , 19 Son et al 13 reported that MvD is observed only at the location of the RNFL defect in eyes with hemiretina involvement and is usually found in the location of more severe RNFL defects in eyes with bi-hemiretinal involvement.…”

“…The structural association between RNFL defect and MvD as shown in Figure 4 may plainly explain (1) why the topography is related to the RNFL defect 9 , 13 , 14 and preconditioned by the presence of βPPA, 1 , 9 , 27 (2) why MvD and glaucomatous damage have a proportional relationship both cross-sectionally 1 – 6 and longitudinally, 3 , 5 , 7 and (3) why our study group showed such a high prevalence of MvD compared to other studies. The NAION eyes had 100% MvD and 100% PPA, while the eyes with compressive optic neuropathy had MvD in only 34.1% of eyes and PPA in only 68.2% of eyes.…”

“…MvD may develop secondarily in response to retinal nerve fiber layer (RNFL) defect 11 or may precede the axonal damage in the ONH in relation to ischemia. 4 , 7 – 10 The cases of nonglaucomatous MvD 3 , 11 , 12 and the spatial association between MvD and RNFL defect 9 , 13 , 14 have led researchers to consider MvD as secondary to RNFL defect.…”

Microvascular alterations of peripapillary choriocapillaris in young adult high myopia detected by optical coherence tomography angiography

“…Our results are in agreement with previous studies using pulse amplitude and other relevant parameters of ocular blood ow to evaluate choroidal perfusion 23,24 . Decreased retinal nerve ber layer and choroidal thickness accompanied by subsequent disc hemorrhage has been linked to myopia 25 . A decline in choriocapillary perfusion may arise from reduced blood demands secondary to choroidal degeneration occurring in highly myopic eyes.…”