The effect of different optical zone diameters on the results of high-order aberrations in femto-laser-assisted in situ keratomileusis

Safety and Effectiveness of Laser in Situ Keratomileusis Using the Teneo 317 Model 2 for Correcting Myopia and Myopic Astigmatism: Results of the U.S. FDA Clinical Trial

PURPOSE

To evaluate the safety and effectiveness of a new aspheric ablation profile for correcting myopia and myopic astigmatism.

METHODS

This prospective, multicenter study included patients who underwent laser in situ keratomileusis (LASIK) using a new aspheric ablation profile of the Technolas Teneo 317 (Model 2) excimer laser (version 1.28 US SW) by Technolas Perfect Vision, Bausch+Lomb, Inc. No nomogram adjustments were made, and the patient's manifest refraction was entered into the laser (for treatment). Postoperative assessments included visual and refractive outcomes. Patients were asked to complete the Patient-Reported Outcomes With LASIK (PROWL) questionnaire preoperatively and postoperatively.

RESULTS

A total of 333 eyes from 168 patients with a mean age of 33 ± 7 years were included. At postoperative 9 months, uncorrected and corrected distance visual acuities of 20/25 or better were seen in 97.8% and 100% of eyes, respectively. None of the eyes lost two or more lines of corrected distance visual acuity. The mean manifest spherical refraction improved from -5.67 ± 2.52 diopters (D) preoperatively to -0.04 ± 0.32 D postoperatively, with 92.7% of eyes achieving residual refractive error within ±0.50 D. Residual refractive cylinder within ±0.50 and ±1.00 D was seen in 93% and 99.4% eyes, respectively. The refractive outcomes were stable throughout the follow-up of 9 months. The proportion of patients satisfied with their vision rose from 27.7% preoperatively to 98.1% postoperatively.

CONCLUSIONS

LASIK performed using a new aspheric ablation profile of the Technolas Teneo 317 (Model 2) excimer laser is safe and effective for correcting myopia and myopic astigmatism, yielding excellent visual and refractive outcomes that were stable over 9 months. [J Refract Surg. 2024;40(8):e544-e553.].

Defocus Curve and Satisfaction of Patients with Presbyopia After LASIK Using the Differential Modulation of Binocular Longitudinal Spherical Aberration

Purpose

To investigate the visual acuity and satisfaction of patients after Zhang & Zheng's corneal laser-enhanced accommodation refraction Q (ZZ-CLEAR-Q) surgery utilizing differential modulation of binocular longitudinal spherical aberration and determine its clinical significance.

Patients and Methods

This prospective observational study enrolled a consecutive cohort of patients with presbyopia who underwent ZZ-CLEAR-Q surgery between December 2020 and January 2023. The study assessed visual acuity, distance-corrected defocus curve, satisfaction, Q factor, manifest spherical equivalent, and primary spherical aberration, among others, at 3 months postoperatively. Additionally, the study conducted a binocular comparison to analyze the clinical significance of setting the different longitudinal spherical aberrations.

Results

A total of 232 eyes of 116 patients were included. The binocular uncorrected distance visual acuity was 20/20 for all patients. At 3 months postoperatively, the binocular uncorrected near visual acuity was Jaeger 1 for 96% of the patients and Jaeger 2 for 100% of the patients. Furthermore, 93.1% of the patients expressed satisfaction. The monocular distance-corrected defocus curve revealed that the dominant eyes had significantly better visual acuity at 0 D (P<0.001), while the non-dominant eyes had significantly better visual acuity across various defocus levels except 0 and -0.50 D (All P<0.05). At 3 months, there were no significant differences between the expected and achieved manifest spherical equivalents, corneal Q factor values, and ocular primary spherical aberration values of both groups.

Conclusion

Patients with presbyopia who underwent ZZ-CLEAR-Q surgery were likely to achieve normal uncorrected visual acuity and be satisfied. The increased depth of field has clinical significance for assisting near vision.

Comparing Effective Optical Zones After Myopic Ablation Between LASIK, PRK, and SMILE With Correlation to Higher Order Aberrations

PURPOSE

To explore size, decentration, and eccentricity of effective optical zones (EOZs) in laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE) and correlate them to higher order aberrations (HOAs).

METHODS

This was a retrospective chart review of 188 eyes that underwent refractive surgery for compound myopia (61 LASIK, 84 PRK, 43 SMILE). EOZ measurements were determined using 1-year postoperative Pentacam (Oculus Optikgeräte GmbH) tangential difference maps. HOA data were measured using Pentacam wavefront aberration Zernike polynomials. Correlations between EOZs and HOAs were analyzed.

RESULTS

The EOZs of LASIK and PRK are smaller than SMILE at 19.54 ± 1.44, 19.39 ± 1.66, and 22.18 ± 2.61 mm2, respectively (P < .001). No difference existed in absolute decentration from corneal vertex (P = .078) or pupil center (P = .131), but horizontal and vertical components differed significantly (P < .001). Smaller EOZ areas were correlated with greater spherical aberration induction (rLASIK = -0.378, rPRK = -0.555, rSMILE = -0.501) and total HOA induction in all groups. Absolute decentration from corneal vertex positively correlated with total HOA (rLASIK = 0.396, rPRK = 0.463, rSMILE = 0.399) and directional vertical coma induction negatively correlated with vertical decentration from the corneal vertex (rLASIK = -0.776, rPRK = -0.665, rSMILE = -0.576) in all groups.

CONCLUSIONS

SMILE results in a larger EOZ than LASIK and PRK, and absolute decentration remains comparable regardless of surgical reference center, despite horizontal/vertical differences. Surgical planning to ensure adequate EOZ size and centration may reduce induction of HOAs, including spherical aberrations and vertical coma. [J Refract Surg. 2023;39(11):741-750.].

Comparison of visual quality after SMILE correction of low-to-moderate myopia in different optical zones

OBJECTIVE

To compare the effects of different optical zones for small-incision lenticule extraction (SMILE) on postoperative visual quality in low-to-moderate myopia.

METHODS

This retrospective case-control study involved patients who underwent SMILE using two optical-zone diameters: 6.5 mm (50 patients, 100 eyes) and 6.8 mm (50 patients, 100 eyes). Uncorrected visual acuity (UCVA), best corrected visual acuity, spherical equivalent (SE), corneal higher-order aberrations (HOAs), and subjective visual-quality questionnaire scores were assessed.

RESULTS

Postoperatively, UCVA and SE did not differ between the two groups (P > 0.05). In both groups, corneal HOAs, spherical aberration, and coma significantly increased at 1 and 3 months postoperatively (P < 0.05), while trefoil was unchanged after surgery (P > 0.05). Corneal HOAs, spherical aberration, and coma significantly differed between the groups at 1 and 3 months (P < 0.05), while trefoil did not (P > 0.05). Visual-quality scores were higher in the 6.8 mm group than in the 6.5 mm group at 1 month (P = 0.058), but not at 3 months (P > 0.05). In both groups, subjective scores significantly decreased at 1 month (P < 0.05) and gradually returned to the preoperative level at 3 months (P > 0.05). The subjective visual-quality scores were negatively and positively correlated with pupillary and optical-zone diameter, respectively (P < 0.05 for both). Objective visual-quality indicators (HOAs, spherical aberration, and coma) were negatively correlated with optical-zone diameter (P < 0.05) but not pupillary diameter (P > 0.05).

CONCLUSION

SMILE in different optical zones effectively corrected low-to-moderate myopia. The larger the optical-zone diameter, the better the early postoperative visual quality.

Comparison of Postoperative Safety, Efficacy, and Visual Quality after SMILE for Myopic Patients with Different Corneal Thicknesses

PURPOSE

To investigate the safety, efficacy, and visual quality of small incision lenticule extraction (SMILE) in different corneal thickness patients with myopia or myopic astigmatism.

METHODS

This prospective cohort study included 191 right eyes of 191 patients. Eyes were divided into three groups according to preoperative central corneal thickness (CCT) (Preoperative central corneal thickness (CCT) was the group indicator.) There were 31 eyes in the thin cornea group (CCT ≤500 um (μm), TC), 94 eyes in the moderate corneal thickness group (CCT ≥501 um (μm) and ≤550 um (μm), MD) and 66 eyes in the thick cornea group (CCT ≥550 um (μm), TK). Comparisons in uncorrected (UDVA) and best-corrected distance visual acuity (BDVA), manifest refractive spherical equivalent (SE), preoperative mesopic/photopic contrast sensitivity (CS), ocular higher-order aberrations (HOAs) at a 6mm analytical pupil diameter, and visual quality questionnaires were made (performed) among the three groups during the postoperative six months. Subgroup analyses were made based on preoperative SE.

RESULTS

The safety indices at six months were 1.15 ± 0.18, 1.14 ± 0.17, and 1.18 ± 0.17, respectively (p = 0.374), and the efficacy indices at six months were 1.07 ± 0.25, 1.12 ± 0.22, and 1.11 ± 0.21, respectively (p = 0.599). The postoperative SE was -0.07 ± 0.52D, -0.14 ± 0.38D, and -0.05 ± 0.46D after SMILE in the three groups, respectively (p = 0.376). No significant difference was found in mesopic/photopic CS, HOAs, and visual quality among different corneal thickness groups and SE groups. Postoperative SE and efficacy indices were the lowest in thin cornea eyes with ultra-high myopia (over -9.00 D).

CONCLUSIONS

SMILE provides comparable safety, efficacy, and visual quality results in different corneal thickness patients. Those with myopia higher than -9.00 D had less efficacy after surgery, especially in thin cornea patients.

Evaluation of morphological features: femtosecond-LASIK flap vs. SMILE cap, and the effects on corneal higher-order aberrations

PURPOSE

The aim of this study is to evaluate morphological features of corneal flap/cap and the correlations with corneal higher-order aberrations (HOAs) changes after femtosecond laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE).

METHODS

This was a retrospective study. Pre- and postoperative (1 and 3 months) corneal HOAs were assessed with Pentacam HR. The corneal flap/cap thickness at 32 points (± 1.5 mm, ± 2 mm, ± 2.5 mm, and ± 3 mm from the corneal vertex on meridian 0°/45°/90°/135°) were measured using anterior segment optical coherence tomography at 3 months postoperatively. Morphological features of corneal flap/cap including predictability (P), uniformity (U), and symmetry (S) were calculated and used for correlation analysis with corneal HOAs changes.

RESULTS

Eighty-six eyes (44 patients) and ninety-six eyes (50 patients) were involved in FS-LASIK and SMILE groups, respectively. Significant thicker corneal flap/cap than the predicted was observed at each measuring point and meridian in both groups (difference > 2.225 μm, the within-subject standard deviation over 6-mm optical zone). There was no statistically significant difference in predictability of corneal flap/cap thickness, while U_6 mm (P < .0001), U₀ (P < .001), U₄₅ (P = .002), U₉₀ (P < .0001), U₁₃₅ (P = .004), S_6 mm (P < .0001), S₀ (P < .001), and S₉₀ (P < .0001) over 6 mm zone were less in SMILE than in FS-LASIK. The changes of corneal tHOAs, Z (3, - 1), Z (3, 1), and SA were significantly correlated with morphological features of corneal flap/cap.

CONCLUSION

Both FS-LASIK and SMILE had good predictability in flap or cap thickness, while the uniformity and symmetry of SMILE cap were better than FS-LASIK flap. The quality of flap/cap was closely associated with the changes of corneal HOAs.

Comparison of the Functional Optical Zone in Eyes With High Myopia With High Astigmatism After SMILE and FS-LASIK

PURPOSE

To compare the functional optical zone (FOZ) in eyes with high myopia with high astigmatism after small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK).

METHODS

In total, 45 eyes of 45 patients with high myopia with astigmatism greater than 2.00 diopters (D) who underwent SMILE or FS-LASIK were enrolled. The FOZ, optical zone decentration, and corneal aberrations were analyzed using Scheimpflug imaging. These values were then compared between the two groups 6 months postoperatively.

RESULTS

No postoperative complications were observed during follow-up. The mean FOZ diameter was 5.03 ± 0.31 mm for the FS-LASIK group and 5.24 ± 0.27 mm for the SMILE group (P = .007), corresponding to reductions of 1.18 ± 0.23 and 1.01 ± 0.21 mm, respectively, compared with the programmed optical zone (POZ) (P = .013). A significant difference was noted in the FOZ on the short axis between the two groups (P = .002), whereas no significant difference was observed on the long axis (P = .088). The FOZ area in the FS-LASIK and SMILE groups was 65.39 ± 6.14% and 70.09 ± 5.46% of the POZ area, respectively (P = .010). There was no significant difference in decentration between the two groups (0.29 ± 0.13 mm for the FS-LASIK group vs 0.30 ± 0.13 mm for the SMILE group, P = .798). A significant increase in spherical aberration was observed in the FS-LASIK group (P < .001). However, the induction of vertical coma was higher in the SMILE group than in the FS-LASIK group (P = .002).

CONCLUSIONS

Eyes with high myopia with high astigmatism following SMILE achieved a larger FOZ and less spherical aberration but a larger vertical coma introduction than following FS-LASIK. [J Refract Surg. 2022;38(9):595-601.].

Achieved and Functional Optical Zone in Myopic Eyes With High Astigmatism After Small Incision Lenticule Extraction

PURPOSE

To investigate the achieved optical zone and functional optical zone in myopic eyes with high astigmatism after small incision lenticule extraction (SMILE).

METHODS

Seventy-five eyes of 75 consecutive patients with myopia before SMILE were included and divided into two groups (no astigmatism group: without astigmatism vs high astigmatism group: with astigmatism > 2.00 diopters). The achieved optical zone, functional optical zone, and corneal aberrations were compared using Scheimpflug imaging at 6 months postoperatively. Correlations between corneal aberrations and functional optical zone were analyzed.

RESULTS

The mean achieved optical zone diameter was smaller in the no astigmatism group than in the high astigmatism group. There were no significant differences in achieved optical zone among the different meridians in each group. The mean functional optical zone diameter was significantly smaller in the no astigmatism group than in the high astigmatism group. Compared with the programmed optical zone, significant reduction of the functional optical zone was found in the two groups. The reduction of the functional optical zone was significantly smaller in the high astigmatism group than in the no astigmatism group, except for the 60°, 90°, and 120° meridians. There were significant correlations between the functional optical zone area and the induced corneal aberrations in the high astigmatism group, except for horizontal coma, whereas significant correlations of functional optical zone with total higher order aberrations and spherical aberration were detected in the no astigmatism group.

CONCLUSIONS

Myopic eyes with high astigmatism following SMILE had a circular achieved optical zone, but the functional optical zone was oval and larger than in eyes without astigmatism. Moreover, a lower spherical aberration was observed in the patients with high astigmatism. [J Refract Surg. 2022;38(4):243-249.].

Comparison of two annular photorefractive intrastromal cross-linking protocols in high oxygen for low-grade myopia through 24-month follow-up

PURPOSE

To compare two annular epithelium-on (epi-on) high oxygen photorefractive intrastromal cross-linking (PiXL) illuminations protocols for treatment of low-grade myopia.

METHODS

In this randomized, single-masked, intra-individually comparative study, healthy individuals with bilateral low-grade myopia (manifest refractive spherical equivalent (MRSE) -0.75 diopters (D) to -2.50 D) were treated with high oxygen epi-on PiXL. One eye was randomized to receive pulsed accelerated 365-nm ultraviolet-A illumination in a central annular zone of 4.0 mm (1 second on, 1 second off; 30 mW/cm² ), and the fellow eye in a 3.5 mm annular zone (0.5 second on, 1 second off; 45 mW/cm² ). Uncorrected distance visual acuity (UDVA), MRSE, low-contrast visual acuity (LCVA), best spectacle corrected visual acuity (BSCVA), endothelial cell count (ECC) and Scheimpflug light scattering depths were assessed through 24-month follow-up.

RESULTS

Twenty-seven participants (54 eyes) were included. The 3.5 mm protocol rendered less subjective ocular discomfort posttreatment and a larger improvement than the 4.0 mm protocol in UDVA: -0.52 (-0.72, -0.32) logMAR (medians and interquartile ranges, IQR) and -0.38 (-0.50, -0.22), p = 0.003 and MRSE: +1.25 D (0.75, 1.50) and +1.0 (0.75, 1.0), p = 0.037. The transient reduction in LCVA was larger with the 3.5 mm protocol (p < 0.01). No adverse events, and no reductions in ECC or BSCVA were noted.

CONCLUSION

Epi-on PiXL in high oxygen reduces myopia in healthy eyes. A larger reduction of myopia and less early posttreatment subjective ocular discomfort can be seen with a smaller treatment zone, but likely at the expense of a transient decrease in low-contrast visual acuity.