Abstract
Purpose :
Choroidal thickness is associated with high myopia and myopic macular degeneration (MMD), but the specific vascular changes that occur within the choroid are unclear. We aim to assess and compare choroidal vascular parameters, using optical coherence tomographic angiography (OCTA), in highly myopic adults with and without myopic macular degeneration (MMD).
Methods :
This is a clinic-based observational study of 128 eyes of 82 patients with axial length (AL) ≥ 26.5mm, enrolled from the high myopia clinic of the Singapore National Eye Centre. Myopic maculopathy (MMD) was graded from fundus photographs according to the META-PM Classification and defined as META-PM category ≥ 2. Swept source OCT (SS-OCT) and OCTA were performed and assessed for choroidal layers (overall choroidal thickness (CT), medium-vessel choroidal layer (MVCL) thickness, large vessel choroidal layer (LVCL)) and choroidal vasculature (choroidal vessel density (%), choroidal branch area (CBA, %) and mean choroidal vessel width (MCVW, mm)).
Results :
CT (r=-0.58, p<0.001) and overall MCVW (-0.58, p<0.001) were negatively correlated with AL, while overall CBA (r=0.61, p<0.001) was positively correlated. Eyes with MMD had significantly lower CT (99±42um vs 189±81um, p<0.001), MCVL thickness (60±14um vs 74±20um, p=0.001), LCVL thickness (86±22um vs 134±58um, p<0.001) and overall MCVW (5.64±0.41um vs 5.94±0.41, p<0.001) than eyes without. Overall CBA (10.26±0.67 vs 9.75±0.62, p<0.001) was significantly higher in eyes with MMD than eyes without. After adjusting for age, gender and axial length, thicker CT (odds ratio (OR) 0.98, 95% confidence interval (CI) 0.97-0.99, p<0.001) and LCVL (OR 0.97 95% CI 0.95-0.99 p=0.004) were significantly associated with lower odds of MMD.
Conclusions :
Decreased choroidal vessel width and increased vascular branching were observed in eyes with long AL. A thinner choroid, particularly LCVL thinning, was associated with greater odds of MMD.
This is a 2020 ARVO Annual Meeting abstract.