Choroidal vascularity index in myopia

Abstract

Purpose : To study the choroidal vascularity index in myopia with respect to ethnicity and choroidal thickness

Methods : A retrospective chart review of all patients with myopia (defined by refraction, history, clinical features, axial length and imaging characteristics) who underwent imaging in terms of enhanced depth spectral domain optical coherence tomography (OCT) at a tertiary eye care centre between 2011 till date were included for analysis in the study. Eyes with significant comorbidities were excluded from the study. Data was analysed in terms of age, ethnicity, gender, type of myopia (simple/ degenerative) and OCT measurements on Choroidal thickness. Data obtained from image J software was used to obtain Choroidal vascularity index in all patients, defined as luminal area upon total choroidal area, to obtain the vascular status of the choroid.

Results : 148 eyes of 95 Patients were evaluated in this study. Median age for the patients being 59 years (+/-16.96 SD) (R- 24-94). The median subfoveal choroidal thickness was 244 microns (+/-116.41 SD). The same when reviewed on the basis of ethnicity, Caucasian, Latin American, East Asian, African American as well as South asian descent did not show any statistically significant difference. The mean CVI in our set of patients was 67.08 % (+/- 6.28% SD). There was no statistically significant difference noted on the base of ethinicity in our patients. Irrespective of the ethnicity, patients with a choroidal thickness (CT) of < 100 microns had a median CVI of 61.74% versus a median CVI of 68.41% in patients with a choroidal thickness of >300 microns. This difference was found to be highly significant. (p=0.0002)

Conclusions : CVI tended to show a significant decrease with thinning of choroid (<100microns) with pathological myopia, when compared with myopes with CT >300 microns. Mean SFCT and CVI in myopes did not show any difference with respect to ethnicity.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

Image 1:
Choroidal vascularity index in a patient with SFCT of 79 microns and a choroidal vascularity index of 58.86%. Figure 1a depicts the delineation of the total choroidal area and figure 1b shows the luminal area measured in terms of areas showing absent pixilation.

 

Image 2:
Choroidal vascularity index in a patient with SFCT of 519 microns and a choroidal vascularity index of 66.96%. Figure 1a depicts the delineation of the total choroidal area and figure 1b shows the luminal area measured in terms of areas showing absent pixilation.