Jul 2026· Romanian Journal of Ophthalmology· Vol 70, pp. 259 - 266· 0 citations· 14 references
Medicine
TL;DR
This study finds a statistically significant difference in vertical keratometry with moderate SIA magnitude, and adds a unique dimension to the literature by explicitly linking a fixed tunnel depth to the SIA vector and keratometric prediction.
Abstract
Objectives The magnitude and axis of surgically induced astigmatism depend on the sclera-corneal tunnel dimensions. Often, the incision depth is subjective, and standardization is rarely emphasized. This study attempts to evaluate a fixed scleral incision depth of 350 µm at 1-week post-op. The aim is to determine the SIA vector and centroid using the Pythagorean theorem and keratometric measurements. Materials and methods This study was conducted from January to July 2025 and recruited 42 patients at a tertiary health institution. All patients received scleral incisions to a depth of 350 µm after preoperative auto-keratometry measurements. Preoperative astigmatism was classified into WTR, ATR, and oblique types. Results The overall mean age was 67.14 (± 9.23) years, with 27 (64.29%) males and 15 (35.71%) females. A positive correlation (r = 0.93, 0.69) was found for pre- and post-operative keratometry. T-test for pre- and post-operative vertical keratometry revealed statistical significance (p < 0.0009). The mean SIA magnitude and axis were 2.05 (± 1.75) D and 77.94º (± 59.68º), respectively. The Wilcoxon signed-rank test showed statistical significance for SIA magnitude (p=0.0003). The centroid was at 22.3º. A 28.57% conversion rate from ATR to WTR was observed, with 71.43% remaining unchanged postoperatively. High prediction accuracy was observed for preoperative horizontal and vertical keratometry (R2 values of 0.93 and 0.74, respectively). Discussion This work adds a unique dimension to the literature by explicitly linking a fixed tunnel depth to the SIA vector and keratometric prediction. These results provide a platform for future research exploring scleral incision depth as a determinant of astigmatic outcomes. Conclusions This study finds a statistically significant difference in vertical keratometry with moderate SIA magnitude. Astigmatic axis transition was unchanged in most patients, likely due to a standardized scleral incision depth. Centroid demonstrated a minimal SIA magnitude on horizontal keratometry. An excellent postoperative keratometry prediction was determined.
SMILE Pro using the VISUMAX 800 femtosecond laser provides safe and predictable correction of myopic astigmatism with good axis alignment, however, the observed undercorrection in higher cylinders suggests that further optimization of astigmatic nomograms may improve refractive accuracy.
İ. İritaş, Z. Burke· International Journal of Oph...· 0 citations
Abstract Purpose To compare thevisual outcomes of small-incision lenticule extraction (SMILE) versus femtosecond laser in-situ keratomileusis (FS-LASIK) in eyes with myopia and high astigmatism. Methods This retrospective study was conducted at a tertiary eye hospital between January 2021 and December 2022. Data were collected from individuals with myopia up to - 10.00 diopters (D) and cylinder ≥ 2.50 D who underwent SMILE (VisuMax 500) or FS-LASIK (MEL 90) and completed a 3-month postoperative follow-up. Results A total of 170 eyes of 123 patients were included: 83 eyes (60 patients) underwent SMILE, and 87 eyes (63 patients) underwent FS-LASIK. The preoperative cylindrical refractive error was - 3.01 ± 0.61 D in the SMILE group and - 3.09 ± 0.66 D in the FS-LASIK group. At 3 months, there was no statistically significant difference in uncorrected visual acuity (UCVA) or manifest refraction spherical equivalent (SEQ) between the two groups (P = 0.26 and P = 0.88, respectively). In the SMILE group, 90.4% of eyes achieved an uncorrected distance visual acuity (UDVA) of 20/20 or better compared to 98.77% with a preoperative corrected distance visual acuity (CDVA) of 20/20 or better. In the FS-LASIK group, 80.46% of eyes achieved a UDVA of 20/20 or better compared to 94.25% with a preoperative CDVA of 20/20 or better. Moreover, 95.1% of eyes in the SMILE group and 94.3% in the FS-LASIK group were within ± 0.50 D. Vector analysis showed comparable results between the two groups in terms of target-induced astigmatism (P = 0.559), difference vector (P = 0.155), index of success (P = 0.091), and angle of error (P = 0.89). The surgically induced astigmatism and correction index were significantly lower in the SMILE group (P < 0.01), whereas the absolute magnitude of error was higher in the SMILE group (P = 0.02). Conclusion SMILE and FS-LASIK have comparable efficacy, predictability, and safety in correcting myopia associated with high astigmatism ( ≥ 2.50 D).
Mai Hong Phan, Luong Minh Huynh, S. K. Foo· Journal of Ophthalmic & Visi...· 0 citations
SMILE Pro performed with the VISUMAX 800 provided favorable early 3-month refractive and astigmatic vector outcomes with a satisfactory safety profile in eyes with high astigmatism, evaluated up to 3 months postoperatively.
L. Tran, T. N. Tran, H. Cung et al.· Vision· 0 citations
A macroscopic incision gape is a prevalent phenomenon in SCOLI and is a significant factor associated with SIA, highlighting the potential for controlling SIA by surgically modulating the incision gape (ΔG).
Xin Fan, P. Lai, Shaofeng Yang et al.· Clinical Ophthalmology· 0 citations
PURPOSE
To evaluate the mid-term impact of Hydrus Microstent implantation on refractive and corneal astigmatism.
METHODS
Eyes undergoing Hydrus Microstent implantation were retrospectively collected. Subjective refraction was required at baseline and at 3 and 12 months postoperatively. Corneal tomography was optional (Pentacam, OCULUS Optikgeräte GmbH, Wetzlar, Germany). Astigmatism was analyzed using three-dimensional power vector analysis.
RESULTS
Forty-two eyes of 35 patients were implanted with a Hydrus Microstent, including 15 eyes treated as a stand-alone procedure and 27 eyes combined with phacoemulsification. In the overall cohort, mean refractive cylinder remained stable from baseline (CD0 = -1.27 ± 0.94 D) to 3 months (CD90 = -1.33 ± 1.29 D, p = 0.6) and 12 months (CD360 = -1.48 ± 1.33 D, p = 0.08). Blurring strength vector B was stable between 3 and 12 months (p = 0.8; pPhacoemulsification = 0.7; pStand-alone >0.9). None of the power vector components J0 and J45 showed significant effects of time, group, or their interaction in any cohort. Tomography data were available for 20 eyes of 18 patients, with half undergoing stand-alone implantation. J0, J45, and B of both anterior and posterior surface astigmatism remained stable over time, with no significant effects of surgical group or of the interaction between group and time.
CONCLUSIONS
Hydrus Microstent implantation does not affect corneal and refractive astigmatism after 12 months.
Colya N. Englisch, K. Boden, A. Trouvain et al.· Current Eye Research· 0 citations
PURPOSE
To identify determinants of posterior corneal astigmatism (PCA) orientation, including anterior corneal astigmatism (ACA) orientation and magnitude.
METHODS
In this retropective cross-sectional observational study, anonymized swept-source optical coherence tomography biometry measurements (IOLMaster 700) were analyzed. Eyes with previous refractive surgery, corneal ectasia, or ocular trauma were excluded. ACA and PCA were classified as with-the-rule, against-the-rule (ATR), or oblique according to the steepest meridian, accounting for the optical reversal of the posterior cornea. Associations with ATR PCA were evaluated using chi-square tests and regression models.
RESULTS
A total of 17,860 eyes from 17,860 patients were included. Among 17,483 eyes with PCA > 0 D and classifiable orientation, 14,335 (81.99%) had ATR PCA. In bivariate analysis, each additional year of age was associated with lower odds of ATR PCA (odds ratio: 0.955; P < 0.001). ATR PCA was present in 9096 eyes (92.85%) with with-the-rule or oblique ACA versus 4960 eyes (67.19%) with ATR ACA (P < 0.001). Among eyes with ATR ACA ≥ 3.00 D, only 14 of 213 (6.57%) exhibited ATR PCA (unadjusted odds ratio: 0.007; P < 0.001). Male sex remained independently associated with lower odds of ATR PCA.
CONCLUSIONS
ACA orientation and magnitude were strongly associated with PCA orientation. Age showed a marked bivariate association, although its independent contribution was attenuated after multivariable adjustment. High-magnitude ATR ACA identified eyes in which PCA often departed from the predominant ATR pattern.
V. Galvis, M. F. García, Veronica Storino et al.· Cornea· 0 citations
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