Journal of refractive surgery最新文献

Purpose: To apply a new method, the Taylor Diagram, and a new concept, the centered root mean square error (cRMSE), in evaluating the performance of IOL formulas.

Methods: The preoperative biometrics were measured with the IOLMaster 700 (Carl Zeiss Meditec) and the postoperative spherical equivalent refraction (SER) was calculated in 888 anonymous patients. The Taylor Diagram was applied to visualize the centered root mean square error (cRMSE) and the correlation coefficient between the predictions and the observations (R_po). Ten formulas across generations were optimized by zeroing the mean predictive error, including SRK I, SRK II, SRK/T, Holladay I, Hoffer-Q, Haigis, Barrett Universal II, VRF, EVO 2.0, and Næser 2. The RMSE and cRMSE at a range of IOL constants around the optimized constant were calculated for SRK/T, Holladay I, Hoffer-Q, and Haigis.

Results: The Taylor Diagram showed improved performance of formulas across generations and the aggregations of the same-generation formulas. The SRK I performed worst with an RMSE of 0.819 and R_po of 0.659, and the EVO 2.0 performed best with an RMSE of 0.341 and R_po of 0.930. At a range of IOL constants, cRMSE is generally much closer to the optimized value than RMSE. At a relatively wide range of constant values, cRMSEs showed no significant discrepancy with the optimized value at the optimized constant.

Conclusions: The Taylor Diagram is a powerful tool for visualizing the performances of IOL formulas. Constant optimization is proved necessary. When the optimization is unavailable, cRMSE is a good approximation. [J Refract Surg. 2025;41(1):e50-e55.].

Purpose: To evaluate a new regression-derived nomogram for high myopic astigmatism in small incision lenticule extraction (SMILE) surgery.

Methods: In this prospective study, data from 180 eyes with myopic astigmatism ranging from -2.50 to -4.50 diopters (D) at 3 months after SMILE surgery were analyzed to construct the astigmatic nomogram. Linear regression between target induced astigmatism and flattening effect formula was derived as a nomogram to adjust astigmatic treatment. The nomogram was applied to 112 eyes with astigmatism ranging from -2.75 to -4.50 D. Subsequently, 143 eyes (manifest refraction group) with astigmatism greater than 2.50 D from 180 eyes were compared with 112 eyes (astigmatic nomogram group). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and refractive outcomes at 3 months postoperatively were recorded.

Results: At 3 months after surgery, there was no difference in postoperative degree of astigmatism or UDVA between the two groups. In the astigmatic nomogram group, 109 (97%) of the eyes were within ±0.50 D compared with 127 (89%) in the manifest refraction group (P = .010). Target induced astigmatism and surgically induced astigmatism were strongly correlated in both groups. However, the average undercorrection in the manifest refraction group was 8.4% (R² = 0.67), whereas the astigmatic nomogram group displayed 2.7% overcorrection (R² = 0.86). Moreover, interestingly, all eyes in the astigmatic nomogram group had an angle of error within -5° to 5° compared with 137 (95.8%) of the eyes in the manifest refraction group (P = .028).

Conclusions: The astigmatic nomogram, based on regression between target induced astigmatism and flattening effect, could enhance the accuracy and predictability of high myopic astigmatism correction in SMILE surgery. [J Refract Surg. 2025;41(1):e65-e72.].

Purpose: To compare 6-month visual outcomes and optical quality after small incision lenticule extraction (SMILE) and toric Implantable Collamer Lens (ICL) (STAAR Surgical Company) implantation for high myopia astigmatism.

Methods: This was a prospective non-randomized study. Overall, 88 eyes of 88 patients with high astigmatism (≥ 2.00 diopters [D]) were enrolled, comprising 42 and 46 eyes in the SMILE and toric ICL groups, respectively. Uncorrected distance visual acuity, corrected distance visual acuity, subjective manifest refraction, and higher order aberrations (HOAs) were examined before and 6 months after surgery. The astigmatism outcomes were further analyzed using Alpins vector analysis.

Results: The preoperative astigmatism was -3.20 ± 0.58 D in the SMILE group and -3.09 ± 0.81 D in the toric ICL group (P = .495), respectively, and the postoperative astigmatism was -0.58 ± 0.39 and -0.72 ± 0.41 D (P = .099) in the SMILE and toric ICL groups, respectively, at the 6-month visit. Surgically induced astigmatism, correction index, difference vector, the magnitude of error, and index of success were comparable between the two groups (P > .05). The Alpins vector analysis indicated a significant difference in absolute values of the angle of error between the two groups (SMILE: 3.05 ± 2.98°, toric ICL: 4.70 ± 3.84°; P = .027). Compared with the SMILE group, the toric ICL group exhibited significantly fewer HOAs at the 6-month follow-up visit, including total HOAs, total coma, horizontal coma, vertical coma, and spherical aberrations.

Conclusions: Both SMILE and toric ICL implantation showed satisfactory efficacy and safety in correcting high myopia astigmatism, whereas toric ICL implantation induced fewer HOAs, leading to better postoperative visual quality. [J Refract Surg. 2024;40(12):e916-e925.].

Purpose: To evaluate the effects of ocular residual astigmatism (ORA) on refractive outcomes for patients with astigmatism after keratorefractive lenticule extraction (KLEx) and to identify the ratio of the ORA/manifest refractive cylinder at the corneal plane (MRC) resulting in a greater index of success (IOS).

Methods: In total, 892 right eyes that underwent KLEx surgery were included. Astigmatic changes were evaluated using Alpins' vector analysis. Surgical outcomes grouped by ORA/MRC and ORA were compared. In stage 1, eyes were divided into two groups with an ORA/MRC cutoff value of 1. In stage 2, patients with an ORA/MRC ratio of greater than 1 were divided into two groups: those with an ORA of 1.25 diopters (D) or greater and those with an ORA of less than 0.50 D. ORA/MRC thresholds leading to a high IOS were analyzed using receiver operating characteristic (ROC) curves.

Results: In stage 1, the mean IOS was 0.13 and 0.21 for the low and high ORA/MRC groups, respectively (P < .001). In stage 2, for high ORA/MRC, the IOS was significantly greater when the ORA was greater than 1.25 D than when the ORA was less than 0.50 D (0.27 versus 0.13, P < .001). ROC curves revealed that participants with an ORA/MRC ratio of greater than 1.8 were more likely to have a higher IOS (P < .001).

Conclusions: Patients with a smaller ORA can obtain better correction results. An ORA/MRC ratio of greater than 1.8 may increase the risk of poor astigmatism correction with KLEx. The application of vector planning may improve the refractive outcomes of KLEx. [J Refract Surg. 2024;40(12):e966-e973.].

Purpose: To develop a predictive model aimed at assessing the likelihood of improvement in corrected distance visual acuity (CDVA) for patients undergoing lenticule extraction using the SmartSight system from SCHWIND eye-tech-solutions. This model evaluates the effectiveness and weight of various clinical and procedural parameters in predicting enhancements in visual acuity.

Methods: Data from 1,262 eyes treated with the SmartSight system, encompassing 86 features, were analyzed. Regression and classification techniques were employed to estimate the probability of CDVA gain, ensuring robust results by comparing different methods. The dataset was divided into training (70%, 883 treatments) and testing (30%, 379 treatments) subsets to ensure comprehensive model evaluation using machine learning methods. Feature significance was determined via analysis of variance and principal components analysis to identify impactful parameters.

Results: Three principal components accounting for more than 70% of the data variance were identified. The first component was primarily linked to system settings, whereas the second and third components were associated with patient gender and laterality. Factors significantly influencing CDVA improvement included a higher spot-to-track distance ratio, tighter track distance, lower pulse energy, lower average laser power, larger spot distance, greater cap thickness, and lower dosage. These variables were ranked based on their impact on CDVA enhancement.

Conclusions: Using low-energy asymmetric spacing for lenticule extraction with the SmartSight system is safe and effective. This approach improves visual outcomes for patients undergoing treatment for myopic astigmatism, offering a reliable method for predicting CDVA improvements. [J Refract Surg. 2024;40(12):e974-e984.].

Purpose: To evaluate the ability of a novel device using virtual implantation to compare the visual performance of two different types of intraocular lenses (IOLs).

Methods: In this prospective, masked, and randomized clinical trial, the visual performance of monofocal and lowadd bifocal IOLs was compared using a device for virtual implantation called VirtIOL. Eighty patients (< 50 years old with healthy eyes and without cataract) were enrolled in this study. Defocus curve and contrast sensitivity were measured using the Freiburg Vision and Contrast Test (FrACT).

Results: Expected defocus curves for the monofocal IOL and the bifocal IOL confirm the utility of the method. The monofocal IOL provided a slightly higher mean visual acuity at 0.00 diopter (D) (mean ± standard deviation: -0.18 ± 0.07 D) compared to the bifocal IOL (-0.16 ± 0.08 D), but also a slightly lower visual acuity from -1.25 to -4.00 D. The mean contrast sensitivity was significantly higher for the monofocal IOL at 7, 11, and 15 cycles per degree. The investigators attest a high usability of the method due to simple communication with the test patient and quick and uncomplicated change of test objects.

Conclusions: The visual performance of the monofocal and bifocal IOLs was as expected, with greater depth of focus but reduced contrast sensitivity for the bifocal IOL. The VirtIOL device represents a promising tool to predict the visual performance of IOLs before implantation in patients. [J Refract Surg. 2024;40(12):e911-e915.].

Purpose: To evaluate effects and related factors of short-time accommodation training on measuring consistency of InnovEyes Sitemap (Alcon/WaveLight; Alcon Laboratories, Inc), NIDEK ARK-1 autorefractor (Nidek Corporation), and subjective refraction (SR).

Methods: One hundred adults (100 eyes) with myopia aged 17 to 40 years were enrolled. Refraction was obtained by InnovEyes Sitemap, autorefraction, and SR in a randomized order. Refractive data of InnovEyes Sitemap were grouped into two groups without and with application of a 2.00 diopter (D) flipper before InnovEyes Sitemap.

Results: The average difference in spherical equivalent (SE) between InnovEyes Sitemap and SR (autorefraction) decreased from -0.56 ± -0.41 D in the without accommodation training group to -0.29 ± -0.14 D in the with accommodation training group, with 95% CI of limits of agreement (LOA) shrinking dramatically (InnovEyes Sitemap-SR: -1.39 to 0.27 vs -0.71 to 0.14 D; InnovEyes Sitemap-autorefraction: -1.23 to 0.40 vs -0.69 to 0.40 D). Furthermore, short-time accommodation training significantly improved the consistency of myopia measurements, with the proportion of SE differences within 0.50 D between InnovEyes Sitemap and SR significantly increasing from 56% to 88% (P < .001). Meanwhile, J0 and J45 showed no significant difference (P > .05) with similar LOA among three techniques in both groups. SE difference of InnovEyes Sitemap (with accommodation training group minus without accommodation training group) was significantly correlated to SE difference between SR and habitual glass refraction (β = -0.312, P = .001), lens thickness (β = 0.262, P = .006), and axial length (β = 0.199, P = .037).

Conclusions: Short-time accommodation training could promote spherical consistency but not deteriorate cylindrical agreement among InnovEyes Sitemap, autorefraction, and SR, and this effect showed more effective in eyes with more undercorrected myopia in habitual prescription, thicker lens, and longer axial length. [J Refract Surg. 2024;40(12):e941-e955.].

Purpose: To compare clinical outcomes of transepithelial photorefractive keratectomy (t-PRK) and conventional epithelium-off PRK (PRK) in patients with high compound myopic astigmatism.

Methods: Sixty eyes of 30 myopic individuals with at least -2.50 diopters (D) of spherical equivalent and 3.00 D of cylindrical refractive error were enrolled in the study. Both eyes of each patient were randomly assigned to either the t-PRK method or epithelium-off PRK as a matched contralateral control group. Refractive outcomes were evaluated 6 months after surgery.

Results: At the 6-month visit, cylindrical refractive error magnitude was lower in the t-PRK (0.51 ± 0.29 D) compared to the PRK (0.67 ± 0.30 D) group (P = .04). The residual astigmatism was 0.50 diopters or less in 23 eyes (76%) in the t-PRK group and 15 eyes (50%) in the PRK group. In vector analysis using the Alpins method, t-PRK resulted in a significantly higher percentage of success of astigmatic surgery (84.68 ± 8.95 in t-PRK versus 79.46 ± 10.88 in PRK, P = .04). Additionally, there was a marginal advantage for the t-PRK group regarding index of success of astigmatism surgery (P = .06) and absolute (P = .08) and arithmetic (P = .07) angles of error compared to the PRK group. Both groups had an equal safety profile.

Conclusions: T-PRK is more accurate for astigmatic correction in high astigmatism than conventional PRK. Both t-PRK and PRK are comparable respecting safety and efficacy. [J Refract Surg. 2024;40(12):e956-e965.].