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Abstract To evaluate the efficiency, predictability, and residual astigmatism between first- and second-generation keratorefractive lenticule extraction (KLEx) surgeries in a prominent astigmatism population. A retrospective cohort study was conducted, and individuals who underwent first- and second-generation KLEx surgeries were enrolled. A total of 31 and 35 eyes were categorized into first and second KLEx groups, respectively. Visual acuity, refraction, topographic parameters, and surgical indices were recorded. Independent t tests were used to compare the postoperative uncorrected distance visual acuity (UDVA), spherical equivalent (SE), and residual astigmatism between the two groups. The difference in UDVA was not significant three months after KLEx surgery (P = 0.509), and the SEs three months after surgery also presented similar values between the two groups (P = 0.552). The first KLEx group demonstrated greater residual astigmatism than did the second KLEx group throughout the three-month follow-up period (all P

The aim of this study is to survey the effectiveness of preservative-free artificial tears containing hyaluronic acid (HA) on post-cataract surgery dry eye disease (DED) prevention. A retrospective cohort study was performed, and patients that received cataract surgeries were divided into either an HA group or non-HA group depending on the artificial tear they used. A total of 37 and 74 eyes were enrolled into the HA and non-HA groups, respectively, after the selection. The primary outcomes are postoperative superficial keratitis and multiple (>3) DED symptoms. The generalized linear model was utilized to calculate the adjusted odds ratio (aOR) and 95% confidence interval (CI) of primary outcomes between the two groups. There were 10 and 2 episodes of superficial keratitis in the non-HA group and HA group, respectively, and the HA group demonstrated a significantly lower incidence of superficial keratitis (p < 0.001). Moreover, 13 and 5 patients developed multiple DED symptoms in the non-HA and HA groups, and the HA group illustrated fewer multiple DED symptoms (p = 0.024). The lower preoperative tear break-up time (TBUT) was correlated with superficial keratitis in the HA group (p = 0.043), while old age, low preoperative TBUT and ocular surface staining were associated with superficial keratitis in the non-HA group (all p < 0.05). Lower preoperative TBUT was correlated with multiple DED symptoms in the HA group (p = 0.020), while female sex, low preoperative TBUT and any DED symptoms were associated with multiple DED symptoms in the non-HA group (all p < 0.05). In conclusion, the usage of preservative-free artificial tears containing HA is associated with lower postoperative DED events.

In this study, we aim to evaluate the risk factors of myopia undercorrection in recipients of second-generation keratorefractive lenticule extraction (KLEx) surgery. A retrospective case–control study was performed, and patients who received second-generation KLEx surgery were enrolled. The cases with myopia undercorrection were matched to non-myopia undercorrection cases with a 1:4 ratio according to age, and a total of 22 and 88 eyes were categorized into the undercorrection and control groups, respectively. Demographic, refractive, topographic, and surgical data were collected preoperatively. A generalized linear model was operated to evaluate the potential risk factors for myopia undercorrection. The uncorrected distance visual acuity (UDVA) at three months postoperation was significantly better in the control group (p = 0.006), and residual myopia and SE were significantly higher in the undercorrection group during the whole follow-up period (all p < 0.001). The UDVA value showed a trend of improvement in the control group (p < 0.001), and the changes to SE and residual myopia were significantly lower in the control group (both p < 0.001). Regarding the risk factors for myopia undercorrection in the whole population and the high-myopia population, a higher manifest sphere power, higher steep keratometry (K), higher topographic cylinder, lower central corneal thickness (CCT) at apex, higher CCT difference and lower residual stromal thickness (RST) correlated to myopia undercorrection (all p < 0.05). In the low-myopia population, only higher myopia and lower RST correlated to myopia undercorrection (both p < 0.05). In conclusion, a high-sphere power and irregular topographic pattern correlated to myopia undercorrection after the second KLEx surgery, especially for individuals with high myopia.

In this study, we aimed to validate a novel light field virtual reality (LFVR) system for estimating refractive errors in the human eye. Fifty participants with an average age of 22.12 ± 2.2 years (range 20–30 years) were enrolled. The present study compared spherical equivalent (SE) and focal line measurements (F1 and F2) obtained by the LFVR system with those obtained by established methods, including closed-field and open-field autorefractors, retinoscopy, and subjective refraction. The results showed substantial agreement between the LFVR system and the traditional methods, with intraclass correlation coefficients (ICC) for SE ranging from 82.7% to 86.7% (p < 0.01), and for F1 and F2 from 80.7% to 86.4% (p < 0.01). Intra-repeatability for F1 and F2 demonstrated strong agreement, with ICC values of 88.8% and 97.5%, respectively. These findings suggest that the LFVR system holds potential as a primary tool for refractive error measurement in optical care, offering high agreement and repeatability compared to conventional methods.

We aim to investigate the potential risk factors for undercorrection in those who have received extend depth-of-focus (EDOF) intraocular lens (IOL) implantation. A retrospective case-control study was conducted in which patients who had received one type of EDOF IOL implantation were included. The patients were divided into the residual group and non-residual group according to the final postoperative sphere power. The preoperative data include the refractive, topographic, endothelial, and biometric parameters obtained. A generalized linear model was generated to yield the adjusted odds ratio (aOR) and 95% confidence interval (CI) of each parameter of the residual myopia. One month postoperatively, the UDVA was better in the non-residual group than in the residual group (p = 0.010), and the final SE was significantly higher in the residual group than in the non-residual group (p < 0.001). In the multivariable analysis, the high preoperative cycloplegia sphere power, higher TCRP, higher corneal cylinder power, and longer AXL significantly correlated to the presence of postoperative residual myopia (all p < 0.05). Furthermore, the higher preoperative cycloplegia sphere power, higher TCRP, higher corneal cylinder power, longer AXL, larger ACD, and larger WTW were significantly associated with postoperative residual myopia in the high-myopia population (all p < 0.001), while the higher preoperative cycloplegia sphere power, higher TCRP, and longer AXL were related to postoperative residual myopia in the low-myopia population (all p < 0.05). In conclusion, high preoperative myopia and corneal refractive power correlate to high risk of residual myopia after EDOF IOL implantation, especially in the high-myopia population.

We aimed to evaluate the postoperative visual and refractive outcomes between the first- and second-generation keratorefractive lenticule extraction (KLEx) surgeries. A retrospective cohort study was conducted and patients who had received first- and second-generation KLEx surgeries were enrolled. A total of 80 and 80 eyes were categorized into the first and second KLEx groups after exclusion, respectively. The primary outcomes were the postoperative uncorrected distance visual acuity (UDVA), spherical equivalent (SE), and safety indexes. An independent t-test and generalized estimate equation were implemented to compare the primary outcomes between the two groups. After the KLEx surgery, the UDVA showed no significant difference between the two groups throughout the study period (all p > 0.05), and the postoperative SE and safety index were also statistically identical between the two groups during the follow-up interval (all p > 0.05). There was a similar trend of visual recovery between the two groups (aOR: 0.967; 95% CI: 0.892–1.143; p = 0.844), while the amplitude of the SE change was significantly lower in the second KLEx group (aOR: 0.760; 95% CI: 0.615–0.837; p = 0.005). Nine and two unintended initial dissection of the posterior plane (UIDPP) occurred intraoperatively in the first and second KLEx groups, respectively, and the second group showed a lower risk of UIDPP (p = 0.032). In conclusion, the efficiency, predictability, and safety are similar between first- and second-generation KLEx surgeries.

Our objective was to evaluate the topographic and surgical factors of early myopic regression between laser in situ keratomileusis (LASIK) and small-incision lenticule extraction (SMILE). A retrospective case–control study was conducted, and 368 and 92 eyes were enrolled in the LASIK and SMILE groups via propensity score matching (PSM). Visual acuity, refractive status, axial length, and topographic/surgical parameters were collected. Multiple linear regression was applied to the yield coefficient and the 95% confidence interval (CI) of the parameters. The cumulative incidence of early myopic regression was higher in the LASIK group (p < 0.001). In the SMILE group, a lower central corneal thickness (CCT) thinnest value and a higher corneal cylinder associated with early myopic regression were observed; meanwhile, in the LASIK group, a lower CCT thinnest value, a higher steep corneal curvature, a larger optic zone, and a lower flap thickness related to early myopic regression were observed (all p < 0.05). In the SMILE group, a higher CCT difference correlated with early myopic regression was observed compared to the LASIK group (p = 0.030), and higher steep corneal curvature and lower cap/flap thickness (both p < 0.05) correlated with early myopic regression were observed in the LASIK group compared to the SMILE group. In conclusion, CCT differences significantly influence early myopic regression in the SMILE group; meanwhile, corneal curvature and flap thickness affect early myopic regression principally in the LASIK group.