ABSTRACT
Objective:To investigate the differences in refractive astigmatism, the anterior corneal surface astigmatism and ocular residual astigmatism between dominant and non-dominant eyes in myopia.Methods:A corss-sectional study was conducted.Two hundred and seventy-six eyes from 138 patients with myopia who were to receive corneal refractive surgery in the Refractive Surgery Center of Tianjin Eye Hospital from January to March 2018 were included.Ocular dominance was assessed with the hole-in-the-card test.The manifest refraction and corneal topography were performed in order to measure the sphericity, spherical equivalent, the astigmatism of anterior corneal surface and total cornea.Vector analysis was used to calculate the value of the ocular residual astigmatism and the components of astigmatism, including J0 and J45 of both the refractive astigmatism and the astigmatism of anterior corneal surface.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Tianjin Eye Hospital (No.201909).Results:It was found that 61.6%(85/138) of the subjects was right-eye dominant.There was no significant difference in sphericity and spherical equivalent, J0 and J45 of the refractive astigmatism and the astigmatism of anterior corneal surface between dominant and non-dominant eyes (all at P>0.05). The magnitude of the ocular residual astigmatism of the dominant eye was 0.607(0.451, 0.808)D, which was lower than 0.701(0.497, 0.901)D of the non-dominant eye, showing a statistically significant difference ( Z=-2.52, P=0.01). Conclusions:In the myopic population with no significant difference in the sphericity and spherical equivalent between the dominant and non-dominant eyes, the magnitude of the ocular residual astigmatism of the dominant eye is significantly lower than that of the non-dominant eye, which may play an important role in the ocular dominance formation.
ABSTRACT
Objective:To investigate the changes, distribution and influencing factors of ocular dominance after small incision lenticule extraction (SMILE).Methods:A retrospective observational case series study was conducted.One hundred and twelve patients (224 eyes) with an average age of 25.1±5.4 years who underwent SMILE surgery at Tianjin Eye Hospital from November 2017 to February 2018 were enrolled.There were 42 male and 70 female patients.The dominant eye was determined using the hole-in-the-card test before and after the surgery.Subjective and objective refraction and uncorrected visual acuity examination were performed before operation, and 1 day, 1 week, 1 month and 3 months after operation.The subjects were divided into switch group and non-switch group based on whether the dominant eye changed after surgery.Binary logistic regression was used to analyze the main influencing factors of dominant eye switches.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Tianjin Eye Hospital (No.201905). Written informed consent was obtained from each patient before any medical examination.Results:There were 18 patients (16.1%) in the switch group including 7 males (38.9%) and 11 females (61.1%), and 94 patients (83.9%) in the non-switch group including 35 males (37.2%) and 59 females (62.8%). No statistically significant difference was found in sex between the two groups ( χ2=0.02, P=0.89). At 1 month and 3 months after the surgery, there was a statistically significant difference in the cylindrical power between the dominant and non-dominant eye ( t=2.31, 1.95; both at P<0.05). Binary logistic regression equation showed that spherical equivalent[odds ratio ( OR)=0.47, 95%confidence interval ( CI): 0.35-0.66]and refractive error difference ( OR=3.04, 95% CI: 2.12-4.36) were significantly related to the eye dominance switches. Conclusions:There were 16.1% of patients having eye dominance switches after SMILE.The dominant eye transfomation is associated with higher spherical equivalent and anisometropia difference before surgery.