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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.
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Objective To investigate the influence of ocular residual astigmatism (ORA) on the correction of astigmatism by FS-LASIK with vector analysis.Methods The records of 182 patients who had accept FS-LASIK between January,2016 and April,2016 were retrosepectively reviewed.The patients whose ORA ≥ refractive cylinder were assigned to high ocular residual astigmatism group (HORA group),ORA ＜ refractive cylinder were assigned to low ocular residual astigmatism group (LORA group).All of the patients were followed 6 months or more.The visual acuity,error ratio and correction ratio were compared between HORA group and LORA group.Results The preoperative ORA of all patients was (0.61 ± 0.27) D,in which ＞ 0.75 D were 58 cases (31.9％),and the HORA group was more than the LORA group (P ＜ 0.05).At postoperative 6 months,there was no statistically significant difference in vision acuity between the HORA group (1.06 ± 0.15) and LORA group (1.08 ± 0.15) (t =0.97,P =0.35).There was statistically significant difference in the error ratio between the HORA group (58.11 ± 63.23) ％ and LORA group (26.12 ± 35.37) ％ (t =3.43,P ＜ 0.05).There was statistically significant difference in the correction ratio between the HORA group (146.45 ± 86.63) ％ and LORA group (122.56 ± 36.31) ％ (t =2.81,P ＜ 0.05).Conclusion The error ratio and correction ratio of astigmatic correction by FSLASIK is significantly higher in eyes with high ORA than in eyes with low ORA.Vector analysis should been carried out before the FS-LASIK.
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PURPOSE: This study was conducted to compare post-operative astigmatic outcomes of two groups, with-the-rule (WTR) and against-the-rule (ATR) astigmatism patients, according to the haptic axis of intraocular lenses (IOLs) inserted in cataract surgery. METHODS: Seventy-two eyes with WTR astigmatism and 79 eyes with ATR astigmatism had cataract surgery through a clear corneal temporal incision. These two groups of eyes were then each divided into 2 groups based on whether the haptic axis of the inserted IOL was at 180degrees or 90degrees. For ATR patients, the outcomes were analyzed according to the three types of IOLs. RESULTS: There was no difference in corneal astigmatism, but WTR patients with a 180degrees haptic axis of the inserted IOL and ATR patients with a 90degrees hepatic axis of the inserted IOL had a significant decrease in postoperative refractive astigmatism (p < 0.05). The changes in ATR astigmatism according to the IOL type were more effective in single-piece acrylic IOLs than in the three-piece polymethylmethacrylate haptic IOL group. CONCLUSIONS: Insertion of the IOL at the 180degrees haptic axis in WTR patients and at 90degrees in ATR patients during cataract surgery may have an effect in reducing pre-existing astigmatism. This observed effect was not consistent among the different types of IOLs.