Patient and public involvement
NCS, chronic systemic diseases, hyperopia, amblyopia, strabismus, PD, ≤ -2.50 D, ocular motility, anisometropia, neurological disorders
EYE DISEASE, IOL, HYPEROPIA, AMBLYOPIA, RESTRICTIVE STRABISMUS, STRABISMUS, RETINA, EXOTROPIA, HIGH MYOPIA, PARALYTIC STRABISMUS, ANISOMETROPIA, NEUROLOGICAL DISORDERS
This retrospective study was conducted at the First Affiliated Hospital of Soochow University between October 2020 and November 2021. The study was approved by the Ethics Committee of the First Affiliated Hospital of Soochow University and adhered to the Declaration of Helsinki. Informed parental consent was obtained for all participants. Patients with concomitant exotropia of ≥ 45 prism diopters (PD) and over 6 years of age were included in the study. The binocular function was measured with the Synoptophore at three levels. The abnormal binocular function was defined as the absence of all grades. Those with high myopia (≤ -6.0 D), hyperopia, anisometropia (≤ -2.50 D), amblyopia, oblique muscle overaction, paralytic strabismus, restrictive strabismus, previous strabismus surgery, or organic eye disease were excluded. Controls were required to have normal binocular vision and a complete absence of any other type of strabismus. Patients with chronic systemic diseases and neurological disorders were also excluded. In total, 50 patients and 26 controls were recruited finally. We compared the difference between the exotropia and the control group. We also made a comparison between the dominant eye and the deviated eye in the exotropia group. The deviated eye was identified as the eye that was always fixated. We chose the right eye of the control group as the dominant eye. All patients underwent a complete ophthalmic examination, including best-corrected visual acuity (BCVA), refraction (Topcon; Tokyo, Japan), prism alternating cover test with accommodative targets for fixation (6 m), ocular motility tests, slit-lamp, posterior segment examination, axial length (IOL Master 700; Carl Zeiss Meditec AG, Jena, Germany) and OCTA. The ability to control exotropia was assessed using the Newcastle Control Score (NCS). Those with a high (poor) NCS (⩾ 4) were identified [All participants underwent OCTA imaging with an undilated pupil. The OCTA images were acquired using a spectral-domain device with software (RTVue-XR Avanti with AngioVue software, OptoVue, Inc., Fremont, CA, USA). A 6*6-mm macular scan was performed on each patient. Split-spectrum amplitude-decorrelation angiography was used to examine the OCTA information. Each scan was automatically segmented to visualize the retinal thickness (RT), SCP, DCP of the retina, and FAZ using AngioVue [Fundus photographs, optical coherence tomography (OCT), and OCT angiography (OCTA) images analysis of constant exotropia. The middle and outer rings centered on the fovea were divided into four quadrants: superior, nasal, inferior, and temporal. The SCP and DCP vessel density of each region was calculated from the binarised image, using the Otsu method [