Abstract
Purpose :
To investigate the relationship between myopia progression, choroidal thickness changes and ocular perfusion pressure (OPP) in healthy myopes with no degenerative fundus changes.
Methods :
In an ongoing longitudinal study of progressing myopes (0.50D change within past 2 years) aged 21-40, visual acuity, refractive error (ShinNippon K 5001), axial length (Lenstar), choroidal thickness (subfoveally and 750μm, 1500μm, and 2250μm nasal, temporal, inferior, and superior; Spectralis EDI-OCT), blood pressure (BP, Omron HEM-705CP), and intraocular pressure (IOP, Canon T-2 NCT) were measured between 3-5pm to control for circadian rhythm effects. Ocular perfusion pressure (OPP) was calculated as OPP = 2/3 * (Mean Arterial Pressure – IOP).
Results :
Fifteen participants have been recruited to date (2m, 13f; 23.47±1.18 years; -4.79±-2.28D). On average the choroid was thinner on the nasal retina, followed by the temporal, subfoveal, inferior and superior quadrants (p<0.001). Choroidal thickness in all three nasal locations decreased significantly with increasing axial length (all p<0.05). In low and moderate myopes with axial lengths less than 26mm, OPP increased with decreasing choroidal thickness at the most eccentric location of the inferior quadrant (R2=0.51, p<0.05), and followed the same trend on the nasal (R2=0.36, p=0.08) and subfoveal regions (R2=0.39, p=0.07).
Conclusions :
Our preliminary data suggest that the nasal choroid thins significantly with increasing axial length. In low and moderate myopes with shorter axial lengths, but not in high myopes, OPP increases as the peripheral inferior, nasal and subfoveal choroidal thickness decreases. These early vascular anatomical and functional differences between moderate and high young myopes need to be evaluated longitudinally and may represent a marker for the development of posterior pole complications with myopia progression.
Acknowledgements: Dr. Kathryn Richdale for extending SUNY CVRC's services and Lenstar biometer to us.
Dr. Suresh Viswanathan for allowing us to use the Heidelberg Spectralis OCT for choroidal measurements.
Ann Nour and Tobin Ansel for technical assistance and guidance throughout the project.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.