Changes of corneal anterior surface morphology and higher-order aberrations after Smart

Authors: Wang Shuhan,  Wang Guiqin,  Yu Aomiao,  Zhao Shaozhen,  Wei Ruihua,  Huang Yue
DOI: 10.3760/cma.j.cn115989-20191119-00501
Published 2021-06-10
Cite asChin J Exp Ophthalmol, 2021, 39(6): 522-527.

Abstract

Objective

To compare the changes of corneal asphericity and higher-order aberrations after smart pulse technology-assisted transepithelial photorefractive keratectomy (Smart) for low and moderate myopia and to investigate the changes in the shape of the front corneal surface in patients with different diopters.

Methods

A non-randomized controlled study design was used.Ninety-eight eyes of 54 patients with moderate or low myopia who underwent Smart surgery in Tianjin Medical University Eye Hospital from November 2018 to March 2019 were included.The 41 eyes of 23 patients with low myopia were set as the low-myopia group, and 57 eyes of 31 patients with moderate myopia were assigned as the moderate-myopia group.The Pentacam anterior segment analysis system was used to measure Q value, index of surface variance (ISV), corneal higher-order aberration (HOA), corneal vertical coma (Z3-1), corneal horizontal coma (Z31) and spherical aberration (Z40) before surgery, 1 month and 3 months after surgery.The anterior surface morphology was compared between the low-myopia and moderate-myopia group.Pearson correlation analysis was used to analyze the correlations between measurement parameters.The study protocol was approved by an Ethics Committee of Tianjin Medical University Eye Hospital (No.2019KY-17). Written informed consent was obtained from each patient before surgery.

Results

Corneal Q value, ISV, HOA and Z40 were 0.445±0.191, 26.973±5.611, 0.671±0.142 and 0.384±0.188, respectively, in the low-myopia group at one month after surgery, which were significantly increased than corresponding preoperative values of -0.273±0.817, 13.784±2.376, 0.433±0.687 and 0.231±0.062 (all at P<0.05). Corneal Q value, ISV, HOA and Z40 were 0.693±0.203, 34.038±5.773, 0.874±0.216 and 0.520±0.129, respectively, in the moderate-myopia group at one month after surgery, which were significantly increased than corresponding preoperative values of -0.309±0.104, 14.838±3.992, 0.409±0.081 and 0.228±0.089 (all at P<0.05). Corneal Q values, ISV, HOA and Z40 in the moderate-myopia group were higher than those in the low-myopia group at different time points after surgery, showing significant differences between the two groups (all at P<0.05). There was no significant difference in postoperative 1-month and 3-month corneal Z3-1 and Z31 between the two groups (both at P>0.05). The results of correlation analysis showed that there were no significant differences in ΔQ value and ΔISV between the two groups, both of which were negatively correlated with spherical equivalent (ΔQ value: low-myopia group: r=-0.364, P=0.044; moderate-myopia group: r=-0.589, P<0.01; ΔISV: low-myopia group: r=-0.298, P=0.039; moderate-myopia group: r=-0.409, P=0.022). ΔQ value and ΔZ40 were positively correlated in the moderate-myopia group (r=0.348, P=0.009); there was no significant correlation between ΔQ value and ΔZ40 in the low-myopia group (r=0.180, P=0.266).

Conclusions

The corneal high-order aberrations and ISV after Smart are increased in comparison with preoperative values in the low-myopia and moderate-myopia eyes, and the corneal Q values change from negative to positive.The effect of Smart on corneal asphericity is less in the low-myopia eyes.

Key words:

Transepithelial photorefractive keratectomy; Corneal asphericity; Higher-order aberration; Q value

Contributor Information

Wang Shuhan

Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin 300384, China

Wang Guiqin

Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin 300384, China

Yu Aomiao

Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin 300384, China

Zhao Shaozhen

Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin 300384, China

Wei Ruihua

Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin 300384, China

Huang Yue

Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Diseases, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin 300384, China

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Updated: June 24, 2021 — 8:37 am