The optical coherence tomography angiography manifestation of strabismus amblyopia with eccentric fixation

Abstract

BackgroundTo explore the application value of optical coherence tomography angiography (OCTA) in patients with strabismus amblyopia accompanied by eccentric fixation.MethodsThe following data were collected from patients with strabismus amblyopia accompanied by eccentric fixation: best corrected visual acuity (BCVA); spherical equivalent (SE) and deviation angle; eccentric fixation distance using OCTA system software tools, with µm as the unit of measurement of the distance between the retinal fixed point and the macular fovea; macular fovea vessel length density (VLD); perfusion density (PD); foveal avascular zone (FAZ) area; and perimeter and circularity of the superficial retinal vascular plexus. The entry criteria were as follows: OCTA scanning quality and signal strength of 8 or above (range 0 to 10).ResultsData from a total of 34 patients were collected: 17 patients with strabismus amblyopia with eccentric fixation were included in the experimental group, and 17 patients without strabismus with central fixation were included in the control group. The average deviation angle of the experimental group was 26.71 ± 25.88 prism dioptres (PD), the amblyopic eye BCVA was 0.24 ± 0.22, the SE was 4.35 ± 2.98 D, the stereoscopic median was 800", the eccentric fixation distance was 632.18 ± 310.62 µm, the macular fovea retinal thickness was 207.82 ± 17.79 µm, the VLD of the superficial retinal vascular plexus was 7.31 ± 3.84 mm− 1, the PD was 0.16 ± 0.08, the FAZ area was 0.28 ± 0.17 mm2, the FAZ perimeter was 2.05 ± 0.56 mm, and the FAZ circularity was 0.67 ± 0.06. These results showed statistically significant differences in the SE and BCVA compared with the lateral eye and the control group, but there were no statistically significant differences in the macular fovea retinal thickness, VLD, PD, or FAZ. The eccentric fixation of amblyopic eyes was directly related to the deviation angle, and the regression formula was as follows: the eccentric fixation distance of amblyopic eyes = 8.319 × the deviation angle + 410.002 (F = 13.878, P = 0.002 < 0.01).ConclusionThe eccentric fixation distance of strabismus amblyopia with eccentric fixation is related to the deviation angle; the greater the deviation angle is, the greater the distance of eccentric fixation.Trial registrationChinese Clinical Trial Registry, ChiCTR1900022830. Registered 27 April 2019, http://www.chictr.org.cn/