Foveal avascular zone area measurements with optical coherence tomography angiography in patients with nanophthalmos.

Abstract

To compare the area of the superficial foveal avascular zone (SFAZ) and deep foveal avascular zone (DFAZ) between patients with nanophthalmos and age matched controls. This prospective and comparative study included 19 eyes from 11 patients with nanophthalmos (study group) and 19 eyes from 19 healthy subjects (control group). SFAZ and DFAZ were measured with optical coherence tomography angiography (OCT-A). All participants underwent a standardised ocular examination including best corrected visual acuity (BCVA), central macular thickness (CMT), subfoveal choroidal thickness (SFCT) anterior chamber depth (ACD), axial length (AL), and refractive error (RE) measurements. Mean SFAZ and DFAZ area in the nanophthalmic eyes and in the control eyes were 0.09 ± 0.12 mm2, 0.10 ± 0.10 mm2 and 0.37 ± 0.10 mm2, 0.37 ± 0.10 mm2 respectively (p < 0.001 and p < 0.001). Mean BCVA, RE, AL, ACD CMT, SFCT, were 0.40 ± 0.34 logMAR Unit, 10.0 ± 2.2 18.1 ± 1.5 mm, 2.15 ± 0.28 mm, 367.1 ± 87.4 µm, 489.2 ± 85.2 µm respectively, in nanophthalmic eyes and there was a statistically significant difference between groups (p < 0.001 for each). There were negative correlations for both SFAZ and DFAZ with RE (r = -0.733 and r = -0.758, p < 0.001), CMT (r = -0.823 and r = -0.82, p < 0.001), SFCT (r = -0.647 and r = -0.717 p < 0.001) for the entire study population. SFAZ and DFAZ area were significantly correlated with AL (r = 0.732 and r = 0.745, p < 0.001) and ACD (r = 0.614 and r = 0.654, p < 0.001). In study group, 5 eyes did not have neither SFAZ nor DFAZ, 3 eyes had only DFAZ and 1 eye had only SFAZ in the OCT-A images. SFAZ and DFAZ area were significantly smaller in nanophthalmic eyes than control eyes.