Association of retinal biomarkers and choroidal vascularity index on optical coherence tomography using binarization method in retinitis pigmentosa
To investigate the association of retinal biomarkers with the choroidal parameters in retinitis pigmentosa (RP).
This prospective study included 69 eyes of 36 patients with RP. Choroidal vascularity index (CVI) was defined as the ratio of luminal area to stromal area after binarization on EDI–OCT images. Choroidal thickness (CT); peripapillary CT, the disruptions of the ellipsoid zone (EZ) and external limiting membrane (ELM); and the existence of disorganization of the retinal inner layers (DRIL) and epiretinal membrane (ERM) in central 1000 μm were noted.
Having DRIL and the disruption of EZ and ELM was significantly associated with higher CVI (p < 0.001, p = 0.001, and p = 0.002 respectively) and lower peripapillary CT in temporal sector (p = 0.031, p = 0.012, and p = 0.043 respectively). Having ERM, the disruption of EZ and ELM was significantly associated with lower visual acuity (VA) (p = 0.044, p < 0.001, and p < 0.001 respectively). The eyes with ERM had significantly lower peripapillary retinal nerve fiber thickness (pRNFLT) (p = 0.040). The mean peripapillary CT significantly and positively correlated with the temporal, nasal, superonasal, and the mean pRNFLT (r = 0.258, p = 0.036, r = 0.252, p = 0.041, r = 0.260, p = 0.035, r = 0.280, p = 0.023 respectively). VA did not significantly correlate with CT, peripapillary CT, or CVI (p > 0.05).
The disruption outer retinal segment integrity was significantly associated with higher CVI and lower peripapillary CT in temporal segment. ERM and disruption of ELM and EZ were associated with worse VA. VA did not significantly correlate with CT, peripapillary CT, or CVI.
KeywordsBinarization method Choroidal thickness Choroidal vascularity index DRIL Ellipsoid zone Epiretinal membrane External limiting membrane Peripapillary choroidal thickness Retinal nerve fiber layer Retinitis pigmentosa
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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