Abstract
Purpose :
The parapapilary choroid is a vascular tissue around the optic nerve. Choroidal thinning and atrophy is known to be associated with several retinal diseases that may affect the vision. In myopia choroidal thinning and its association with myopic macular degeneration is known to occur. The purpose of this study was to determine the PPCT in myopic eyes and to understand its correlations with optic disc and other ocular parameters.
Methods :
171 eyes (98 female eyes) of 86 subjects were studied. All had axial length >23.5 mm. Subjects underwent eye evaluation and SDOCT, using enhanced depth imaging. Subjects with poor images and coexisting ocular morbidity were excluded. For SD OCT a protocol was followed by doing A 360-degree 3.4 mm diameter parapapillary circle scan. Choroidal thickness was delineated as the area of visible choroidal vasculature between the RPE-Bruchs complex and the choroidal-scleral Interface. Correlation of RNFL and choroidal thickness measurements was assessed for each parapapillary location using Pearson correlation.
Results :
Mean values were for age, 24.83+9.29 years, axial length was 25.05+1.17 mm. sph. equivalent -4.97+-3.2, PPCT values were superior, 186.83+-65.68 u, nasal, 164.85+-58.57, temporal 167.39+-71.58, and inferior, 138.29+-51.46. Superior PPCT was found to correlate positively significantly with sph. equ. (P<0.001, r=0.344) BCVA (P<0.001;r=0.354)anterior chamber depth (P=0.007, r=0.207), presence of PPA (P<0.001,r=0.442), width of PPA (P<0.001,r=0.477), global RNFLT (P<0.001;r=0.352) and choroidal thickness at fovea (p<0.001;r=0.537). Negative significant correlations were found with axial length ( P<0.001;r=-0.355), Horizontal diameter of disc ( P=0.001;r= -0.262), vertical diameter of disc ( P=0.016;r=-0.183) Similiar correlations were also seen with nasal, inferior and temporal PPCT. Paired T-test showed the superior, nasal and temporal PPCT to be significantly thicker than inferior PPCT P<0.001.
Conclusions :
The peripapillary choroidal thickness in myopia was found to be significantly thinner inferiorly, compared to superior, nasal and temporal segments. PPCT was also found to correlate significantly with increasing global RNFLT and with the vertical and horizontal diameters of the optic disc. These correlations need to be further studied to understand their possible implications in subjects with glaucoma and myopia.
This is a 2020 ARVO Annual Meeting abstract.