Journal of refractive surgery最新文献

Purpose: To describe tomographic alterations leading to refractive changes after Descemet membrane endothelial keratoplasty (DMEK) and to evaluate three keratometric adjustment methods compared to conventional unadjusted formulas.

Methods: Biometric, topographic, and refractive data from a retrospective case series of patients who had undergone phacoemulsification and DMEK were collected. Eyes with corneal scarring or preoperative epithelial edema preventing accurate keratometric readings were excluded. Mean prediction error, mean (MAE), and median absolute error (MedAE), standard deviation, and percentage of eyes within ±0.50, ±1.00, and ±1.50 diopters (D) were calculated using four methods: conventional (SRK/T, Haigis, Barrett Universal II); with a keratometric adjustment using a fictious keratometric index based on the change of preoperative to postoperative back to front (BF) ratio; applying keratometric adjustment only when residual hyperopia was expected based on preoperative parameters (HaigisCombi); and a linear regression keratometric adjustment (Haigis-D).

Results: A total of 112 eyes (93 patients) from two centers were included. Significant changes were found in all tomographic parameters. Mean posterior keratometry and asphericity, BF ratio, and relative pachymetry correlated with postoperative hyperopic error. The three keratometric adjustments significantly reduced the hyperopic prediction error. The Haigis-D formula obtained the lowest MAE and MedAE (0.62 and 0.52 D, respectively), whereas the highest percentage of eyes within ±1.00 D was achieved by the HaigisCombi (83.8%).

Conclusion: The three methods demonstrated a reduction in prediction error and the proportion of hyperopic results when compared to the unadjusted formulas. The most balanced method was based on the BF ratio as a predictor of residual hyperopia, whereas the linear keratometry correction seemed more extrapolable. Results were mixed when adjustments based on data from one center were applied to data from the other center. The proposed keratometric adjustments need to be validated by a prospective study.

Purpose: To remove the maximum amount of pigment placed in the corneal stroma in a previous cosmetic femtosecond laser-assisted keratopigmentation procedure and restore visual function.

Methods: Case report.

Results: A 53-year-old man presented with bilateral cosmetic femtosecond laser-assisted keratopigmentation that resulted in decreased uncorrected and corrected distance visual acuity, poor visual quality, and increased corneal aberrations. A femtosecond laser was used to create a corneal flap, followed by excimer laser ablation to remove stromal pigment within an 8.5-mm optical zone. This approach resulted in restoring corneal transparency with the regularization of corneal architecture, reduction in corneal aberrations, and elimination of induced ametropia, with subsequent improvement in visual acuity.

Conclusions: In cases requiring the reversal of femtosecond laser-assisted keratopigmentation, a combined femtosecond laser and excimer laser-assisted stromal ablation may effectively remove pigment restoring corneal transparency, reduce corneal aberrations, and improve visual acuity by addressing induced refractive error.

Purpose: To report the incidence of accommodative spasm after laser in situ keratomileusis (LASIK) for hyperopia and to identify potential risk factors.

Methods: This monocentric retrospective study included all patients who underwent LASIK for hyperopia. Preoperative and intraoperative variables were recorded to identify factors associated with accommodative spasm. Patients were classified as having accommodative spasm if a postoperative myopic shift was observed in manifest refraction during the first 3 months, whereas cycloplegic refraction showed emmetropia or hyperopia.

Results: A total of 169 eyes of 100 patients were analyzed. At the last visit, the spasm group showed a statistically significant improvement in uncorrected and corrected distance visual acuity compared to the 3-month visit (P < .05). Although an improvement was observed between the 6-month and the last visit, it did not reach statistical significance. Sphere and spherical equivalent values also improved statistically significantly at 3 and 6 months (P < .05), decreasing myopization. The spasm rate was 21.9% (37 eyes) at 3 months after surgery and 5.3% (9 eyes) at the last visit. Logistic regression revealed a statistically significant association between having an accommodative spasm and having a preoperative latent hyperopia greater than 1.25 diopters (odds ratio: 4.227, P = .049).

Conclusions: Twenty percent of patients develop an accommodative spasm after hyperopic LASIK treatment at 3 months after surgery. However, 75% of those spasms resolve between 6 and 12 months after surgery, by either performing vision therapy or simply observing the patient without specific treatment. Uncorrected preoperatively latent hyperopia greater than +1.25 diopters was associated with postoperative accommodative spasm in this cohort.

Purpose: To evaluate the efficacy, predictability, safety, and complication profile associated with the latest posterior chamber phakic Implantable Collamer Lenses (ICLs) featuring a central port (models V4c and V5; STAAR Surgical).

Methods: This PROSPERO-registered systematic review and single-arm meta-analysis included prospective ICL V4c or V5 implantation studies in adults without ocular comorbidities. Databases searched included PubMed, Embase, and the Cochrane Library through May 2025. Primary outcomes were efficacy, predictability, and safety; secondary outcomes included intraocular pressure, endothelial cell density, and complications.

Results: Twenty-seven studies comprising 2,204 myopic eyes were included, with a mean follow-up of 13.84 months. Final uncorrected distance visual acuity (UDVA) averaged 0.057 ± 0.022 logarithm of the minimum angle of resolution (logMAR), with 80.23% achieving 20/20 or better. The mean efficacy index was 1.103 ± 0.019. Predictability was high: 87.45% of eyes were within ±0.50 diopters (D) of the intended refraction. The mean corrected distance visual acuity (CDVA) was 0.014 ± 0.020 logMAR, and the safety index averaged 1.185 ± 0.021. Intraocular pressure remained stable postoperatively (15.98 ± 0.531 mm Hg), and endothelial cell density showed a statistically significant but clinically acceptable decrease. Complications were infrequent, with no vision-threatening events reported.

Conclusions: This meta-analysis of ICLs with a central port (V4c and V5) demonstrates high levels of efficacy, refractive predictability, and safety for correcting moderate to high myopia. The incidence of serious adverse events was low, and results were consistent across a broad range of prospective studies. Continued long-term follow-up and geographically diverse populations are warranted to further validate these findings.

Purpose: To compare the posterior keratometry (PK) values obtained with three instruments based on optical coherence tomography (Anterion [Heidelberg Engineering], IOLMaster 700 [Carl Zeiss Meditec AG], and MS-39 [CSO]), and one Scheimpflug camera biometer (Pentacam AXL Wave; Oculus Optikgeräte GmbH). The average keratometry (Kave), total corneal power (TCP), anterior-to-posterior ratio (A/P ratio), and posterior corneal astigmatism (PCA) were also compared.

Methods: Measurements by the four instruments, expressed in diopters (D), were compared using repeated measures analysis of variance, when they were normally distributed, or Friedman's test, when they were not.

Results: One hundred eyes (100 consecutive patients) scheduled to undergo cataract surgery were prospectively enrolled. Statistically significant differences among the Anterion, IOLMaster 700, MS-39, and Pentacam AXL Wave were detected for PK: Anterion: -6.08 ± 0.23 D, IOLMaster 700: -5.77 ± 0.23 D, MS-39: -6.15 ± 0.26 D, and Pentacam AXL Wave: -6.26 ± 0.26 D (P < .0001); for Kave: Anterion: 43.19 ± 1.50 D, IOLMaster 700: 43.35 ± 1.49 D, MS-39: 43.36 ± 1.53 D, and Pentacam AXL Wave: 43.22 ± 1.55 D (P < .0001); for the A/P ratio: Anterion: 1.19 ± 0.02, IOLMaster 700: 1.12 ± 0.02, MS-39: 1.20 ± 0.03, Pentacam AXL Wave: 1.22 ± 0.03 (P < .0001); and for TCP: Anterion: 42.69 ± 1.51 D, IOLMaster 700: 43.36 ± 1.49 D, MS-39: 42.92 ± 1.52 D, and Pentacam AXL Wave: 42.35 ± 1.55 D (P < .0001). PCA revealed significant differences for the KP(45) and KP(0) vectors (P < .0001).

Conclusions: The four instruments showed different PK values. The largest difference was observed with the IOL-Master 700, which provided the flattest PK and the lowest A/P ratio. The measurements cannot be considered interchangeable, and this should be considered when entering PK values into calculators using this parameter for IOL power.

Purpose: To develop a novel intraocular lens (IOL) power calculation formula by predicting the actual lens position (ALP) in patients with Marfan syndrome who have ectopia lentis undergoing IOL implantation.

Methods: Patients with Marfan syndrome undergoing in-the-bag IOL implantation or scleral-fixated IOL (SF-IOL) implantation were prospectively recruited. ALP was calculated by adding anterior chamber depth to half of the IOL thickness, measured using the IOLMaster 700 (Carl Zeiss Meditec). A generalized linear model was developed to predict the ALP and integrated into effective lens position (ELP) predictions. A supplementary strategy was adjusting axial length (AL). The proposed formulas were evaluated by refraction prediction error (PE) and its absolute value (AE) and compared with both classic and state-of-the-art formulas.

Results: A total of 408 patients (408 eyes) were divided into a training set and a validation set. ALP was significantly correlated with ELP, but the discrepancy increased with longer AL. A significant anterior shift of ALP was observed in the SF-IOL procedure compared to in-the-bag IOL implantation. The ALP prediction model, stratified by AL and surgical procedure, was constructed in the training set. In the validation set, the ALP-based formula demonstrated the highest proportion of AE within 1.00 diopter (D) (83.78% for AL ≤ 24 mm; 92.50% for AL > 24 mm) and significantly reduced extreme PE compared to other formulas. For SF-IOL implantation, the AL-adjusted formula was the most accurate. An online calculator was developed to facilitate its application.

Conclusions: The proposed formulas demonstrated superior accuracy for IOL power calculation in patients with Marfan syndrome compared to existing formulas.

Purpose: To compare the accuracy of formulas for intraocular lens (IOL) power calculation in eyes needing myopic targets between -2.50 and -3.00 diopters (D).

Methods: Patients who underwent phacoemulsification needing a myopic target were enrolled in a single-center retrospective study. IOL power was calculated with newer formulas (Barrett Universal II [BUII], Cooke K6, EVO 2.0, Hoffer QST, and Kane) and older ones (Haigis, Hoffer Q, Holladay 1 and 2, and SRK/T). Trueness, precision, and accuracy of the prediction error (PE) and the percentages of eyes within certain PE thresholds were compared. Patients were grouped based on the implanted IOL (iSert255 [Hoya] or SN60WF [Alcon Laboratories, Inc]).

Results: One hundred thirty eyes were enrolled in the iSert 255 group and 105 eyes in the SN60WF group. No statistically significant difference was observed in trueness among formulas, due to constant optimization. In the iSert 255 group, the accuracy of the Holladay 1 formula was lower (P < .05) compared to the Cooke K6, EVO 2.0, and Kane formulas. In the SN60WF group, the accuracy of the Holladay 1 formula was lower (P < .005) compared to the BUII, EVO 2.0, Hoffer QST, and Kane formulas. The percentage of eyes with an absolute PE less than 0.50 D was highest with newer formulas (77% to 81% in the iSert 255 group and 83% to 85% in the SN60WF group) and lowest with the Holladay 1 formula (58 and 69%, respectively).

Conclusions: Newer formulas have good accuracy in eyes with intentional myopic targets, whereas the use of older formulas, especially the Holladay 1, is not recommended.

Purpose: To assess the clinical outcomes and postoperative complications of the EVO Toric Implantable Collamer Lens (TICL) (STAAR Surgical) with a central port correction over a 5-year follow-up in patients with low and normal vault.

Methods: This retrospective study included 240 eyes from 120 patients divided in two groups based on early postoperative vault: low (< 250 μm; n = 77) and normal (⩾ 250 μm; n = 163). Uncorrected (UDVA) and corrected (CDVA) distance visual acuity, refraction, astigmatism vectorial analysis, complications, and secondary surgeries were assessed at 1 month, 12 months, and 5 years postoperatively.

Results: At 5 years, both groups showed significant improvement in UDVA and CDVA (P < .001), with no intergroup differences. The safety index was 1.17 ± 0.25 in the low vault group and 1.18 ± 0.32 in the normal vault group (P = .634); efficacy index was 1.02 ± 0.24 and 1.00 ± 0.29, respectively (P = .542). Manifest cylinder at 5 years was similar between groups: -0.41 ± 0.56 and -0.48 ± 0.61 diopters (P = .526). Both groups demonstrate a similar tendency for undercorrection, with target induced astigmatism values higher than surgically induced astigmatism values, at 1 (P = .813) and 5 (P = .466) years. The mean deviation vector and correction index was statistically similar between groups (P > .05). The absolute mean angle of error was also similar between groups (P = .128). TICL axis repositioning occurred in 4 cases (5.19%) in the low vault group and in 5 cases (3.08%) in the normal vault group.

Conclusions: TICL implantation provides excellent long-term refractive and rotational stability regardless of vault height. Low vault was not associated with significant safety concerns, supporting TICL efficacy across a broad range of postoperative vault values.