Manifest Refraction Spherical Equivalent Research Articles

Comparing clinical outcomes of Optiwave Refractive Analysis, Lenstar, and surgeon’s modified method for intraocular lens power calculation in Asian eyes

The study aimed to compare the accuracy of intraocular lens (IOL) calculation to predict postoperative refraction by Optiwave Refractive Analysis (ORA), Lenstar LS 900, and the surgeon’s Modify method in normal Asian eyes. The IOL power of the Lenstar group was calculated according to Lenstar LS 900, whereas the surgeon's Modify group used topography, axial length (AL) of Lenstar, and Barrett Universal II online formula. Intraoperative aphakic measurements and IOL power calculations were obtained with the ORA system. From the results acquired through Lenstar, Modify, and ORA, the surgeon used his judgment to select the actual IOL power. Postoperative manifest refraction spherical equivalent (MRSE) was obtained 2 months after surgery. The prediction error (PE) was calculated as the difference between the postoperative MRSE and the target refraction proposed by three methods. AL, anterior chamber depth (ACD, measured from corneal endothelium to lens), lens thickness (LT), and ACD + 1/2LT were also included in the survey. In 67 eyes, the average real PE was smaller for the Lenstar (0.06 ± 0.44) and Modify (− 0.05 ± 0.40) than for the ORA group (− 0.25 ± 0.60, p < 0.05). The ORA system demonstrated the best results of IOL power selection in eyes with a normal range of ACD + 0.5 LT (5.2–5.6 mm) in Asian eyes.

Influence of Preoperative Parameters on the Ratio of Keratometric Change per Diopter of Attempted Spherical Equivalent (∆K/∆SEQ) for Myopic Correction Within LASIK, PRK, and SMILE.

To compare 3 of the most common corneal refractive procedures; PRK, LASIK, and SMILE assessing ΔK/ΔSEQ ratio and its correlation with preoperative demographics including age, keratometry, pachymetry, cylinder value, and attempted myopic correction. The goal was to analyze the relative strength of each preoperative parameter in accounting for changes in ∆K/∆SEQ. A total of 370 eyes from 102 male and 97 female patients (173 eyes PRK, 153 LASIK, and 44 SMILE) with ages ranging from 20 to 51 underwent refractive surgery for myopia between -0.25 and -7.71 D manifest refraction spherical equivalent (MRSE). All surgeries were performed at a single surgery center in Draper, Utah. The Pentacam was used for all optical measurements and data were gathered pre-operatively and then again 1-year post-operatively. Only patients who achieved emmetropia at a visual acuity of 20/25 or better were included. The mean ΔK/ΔSEQ ratio for LASIK (0.839 ± 0.020) was significantly greater than that of PRK (0.775 ± 0.022) and SMILE (0.709 ± 0.046). Age was found to negatively correlate with ΔK/ΔSEQ for both LASIK (r = -0.177) and SMILE (r = -0.451) procedures. Pre-op keratometry was found to negatively correlate with ΔK/ΔSEQ for LASIK (r = -0.202) but not for PRK or SMILE. Pre-op pachymetry was not correlated with ΔK/ΔSEQ for any of the procedures. Attempted myopic spherical equivalent (SEQ) correction was positively correlated with ΔK/ΔSEQ for LASIK (r = 0.236), PRK (r = 0.459), and SMILE (r = 0.304). Lastly, pre-op cylinder value was found to be correlated to ΔK/ΔSEQ in SMILE (r = -0.367), but not in LASIK or PRK. The ΔK/ΔSEQ ratio not only differs depending on the procedure being done but also by pre-operative factors such as age, keratometry, attempted correction, and cylinder value. Multiple linear regression analysis revealed that the attempted correction had the greatest effect on ∆K/∆SEQ out of all parameters in LASIK and PRK. For SMILE, age had the greatest predictive value of the change in ∆K/∆SEQ. While the exact effect of these parameters will vary by surgeon, all of these should be factored into a refractive surgeon's nomograms in order to achieve optimal visual outcomes for their patients.

Prediction of Posterior-to-Anterior Corneal Curvature Radii Ratio in Myopic Patients after LASIK, SMILE, and PRK Using Multivariate Regression Analysis.

The ratio of posterior-to-anterior curvature radii of the cornea (P/A ratio) is an important element in determining corneal refractive power. P/A ratio has been well studied in patients prior to undergoing refractive surgery, but its postoperative value remains less so. We aimed to examine the value of preoperative characteristics of refractive surgery patients in predicting the 1-year postoperative P/A ratio in LASIK, PRK, and SMILE using both linear and multivariate regression analyses. This was a retrospective study that included patients with manifest refraction spherical equivalents (MRSE) from -7.71D to -0.25D. In total, 164 eyes underwent LASIK, 183 underwent PRK, and 46 underwent SMILE. All patients had preoperative and 1-year postoperative front sagittal and back sagittal keratometry measurements at 4, 5, and 6 mm around the corneal vertex. Postoperative P/A after LASIK, PRK, and SMILE was found to be significantly correlated with MRSE and preoperative P/A. Stepwise variable selection in multivariate regression revealed that spherical equivalent was the most significant predictor of postoperative P/A. When coupled with other preoperative characteristics, including P/A, age, asphericity, and keratometry, the multivariate regressions were able to produce models with high predictive value in LASIK (adjusted R2: 0.957), PRK (adjusted R2: 0.934), and SMILE (adjusted R2: 0.894).

Long-term results of hyperopic ablations using alcohol-assisted PRK and FS-LASIK: comparative study.

To evaluate the long-term visual and refractive outcomes of hyperopic excimer ablation using alcohol-assisted photorefractive keratectomy (PRK) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). American University of Beirut Medical Center, Beirut, Lebanon. Retrospective, matched comparative study. Eyes that underwent alcohol-assisted PRK were compared to matched eyes that underwent FS-LASIK. All patients were followed up for at least 3 years after surgery. The refractive and visual outcomes of each group were compared at different postoperative time points. The main outcome measures were spherical equivalent deviation from target (SEDT), manifest refraction, and visual acuity. 83 eyes underwent alcohol-assisted PRK and 83 matched eyes underwent FS-LASIK. Preoperative manifest refraction spherical equivalent was 2.44 ± 1.18 diopters (D) and 2.20 ± 0.87 D ( P = .133) in the PRK and FS-LASIK groups, respectively. Preoperative manifest cylinder was -0.77 ± 0.89 D and -0.61 ± 0.59 D ( P = .175) for the PRK and LASIK groups, respectively. 3 years postoperatively, SEDT was 0.28 ± 0.66 D and 0.40 ± 0.56 D for the PRK and LASIK groups, respectively ( P = .222), whereas manifest cylinder was -0.55 ± 0.49 D and -0.30 ± 0.34 D for PRK and LASIK, respectively ( P < .001). The mean difference vector was 0.59 ± 0.46 for PRK and 0.38 ± 0.32 for LASIK ( P < .001). 13.3% of PRK eyes and 0% of LASIK eyes had >1 D of manifest cylinder ( P = .003). Both alcohol-assisted PRK and FS-LASIK are safe and effective for the treatment of hyperopia. PRK induces slightly more postoperative astigmatism than LASIK. Larger optical zones and recently introduced ablation profiles that lead to a smoother ablation surface might improve the clinical results of hyperopic PRK.

Comparison of planned versus achieved central corneal stromal thickness reduction in SMILE versus FS-LASIK: a retrospective study

Accuracy of planned corneal stromal thickness (CST) reduction is essential to the safety of laser vision correction. This study was to compare the accuracy of the planned central CST reduction in small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK). A total of 77 patients (43 for SMILE, 34 for FS-LASIK using Custom-Q algorithm) were included in this retrospective study. At postoperative 6–18 months, the central CST reduction was overestimated by 18.49 ± 6.42 μm in the SMILE group (P < 0.001) and underestimated by 2.56 ± 7.79 μm in the FS-LASIK group (P = 0.064). The planned-achieved difference (PAD) of central CST reduction was positively correlated with preoperative manifest refraction spherical equivalent (MRSE) and with planned central CST reduction in both groups. When calculated by manifest refraction (MR) without nomogram adjustment, the central CST reduction was overestimated by 11.14 ± 6.53 μm in the SMILE group and underestimated by 2.83 ± 7.39 μm in the FS-LASIK group. The PAD of central CST reduction without nomogram was significantly narrowed in SMILE and maintained in FS-LASIK, suggesting estimation using MR without nomogram adjustment may be feasible for SMILE and FS-LASIK in clinical practice.

Effect of preoperative pupil offset on corneal higher-order aberrations after femtosecond laser-assisted in situ keratomileusis

BackgroundThis study aimed to investigate the relationship between multiple higher-order aberrations (HOAs) subgroups and pupil offset, as well as to analyze the factors affecting postoperative corneal HOAs in patients with different degrees of refractive errors.MethodsWe enrolled 160 patients (316 eyes) aged ≥ 18 years who had undergone femtosecond laser-assisted in situ keratomileusis (FS-LASIK) treatment. Based on the relationship between the preoperative pupil offset and the postoperative ΔHOAs, all patients were divided into two groups: group I (pupil offset ≤ 0.20 mm) and group II (pupil offset > 0.20 mm). All of the eyes had low to high myopia with or without astigmatism (manifest refraction spherical equivalent (MRSE) < -10.00 D). Uncorrected distance visual acuity, corrected distance visual acuity, MRSE, pupil offset, central corneal thickness, corneal HOAs, vertical coma (Z3−1), horizontal coma (Z31), spherical aberration (Z40), trefoil 0° (Z33), and trefoil 30° (Z3−3) over a 6 mm diameter central corneal zone diameter were evaluated preoperatively and at 1 and 3 months postoperatively.ResultsOur result revealed significant differences in postoperative corneal total root mean square (RMS) HOAs, RMS vertical coma, RMS horizontal coma, RMS spherical aberration, and RMS trefoil 30° between group I and group II. ΔMRSE was found to be an effective factor for ΔRMS HOAs (R2 = 0.383), ΔRMS horizontal coma (R2 = 0.205), and ΔRMS spherical aberration (R2 = 0.397). In group II, multiple linear regression analysis revealed a significant correlation between preoperative pupillary offset and Δtotal RMS HOAs (R2 = 0.461), ΔRMS horizontal coma (R2 = 0.040), and ΔRMS trefoil 30°(R2 = 0.089). The ΔRMS vertical coma effect factor is the Y-component, and the factor influencing ΔRMS spherical aberration was ΔMRSE (R2 = 0.256).ConclusionA small pupil offset was associated with a lower induction of postoperative corneal HOAs. Efforts to optimize centration are critical for improving surgical outcomes in patients with FS-LASIK.

Supracor Multifocal Corneal Laser-Assisted In Situ Keratomileusis Procedure for the Correction of Presbyopia in Hyperopic Eyes.

To investigate the outcomes of unilateral Supracor treatment to enhance near vision while maintaining good distance vision in hyperopic eyes. This prospective interventional study includes consecutive hyperopic patients with presbyopia. All eyes underwent femtosecond laser-assisted in situ keratomileusis treatment for hyperopia with an additional Supracor multifocal treatment algorithm in nondominant eyes. Monocular and binocular uncorrected and spectacle-corrected distance visual acuity (UCDVA and SCDVA), monocular and binocular uncorrected near visual acuity (UNVA), and distance-corrected near visual acuity at 40 cm and high-order aberration changes and complications were evaluated for 6 months. Sixty-four patients with a mean age of 51.91 ± 3.64 were enrolled. After 6-month follow-up, the mean binocular UCDVA and UNVA were 0.03 ± 0.05 and 0.04 ± 0.06 logMAR, respectively. UCDVA (logMAR) of nondominant and dominant eyes was 0.30 ± 0.18 and 0.03 ± 0.05, respectively. Preoperative and postoperative mean ± standard deviation manifest refraction spherical equivalent was +1.84 ± 0.75 and -0.48 ± 0.57, respectively, in nondominant eyes and +1.77 ± 0.69 and +0.12 ± 0.33, respectively, in dominant eyes. No complications were observed. Supracor procedure in nondominant eyes may improve functional near, intermediate, and distance vision without significant photic phenomena in presbyopic patients with low and moderate hyperopia.

Network meta-analysis comparing efficacy and safety of different protocols of corneal cross-linking for the treatment of progressive keratoconus.

This study aimed to determine the preferred protocol of corneal collagen cross-linking (CXL) in the treatment of progressive keratoconus. Relevant studies were retrieved in PubMed, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL). Maximum keratometry value (Kmax), best spectacle-corrected visual acuity (BSCVA), manifest refraction spherical equivalent (MRSE), and endothelial cell density (ECD) were evaluated in network meta-analysis. Eight randomized controlled trials (RCTs) were included. Low-level evidence suggested that aCXL with 30mW/cm2 for 3min (aCXL-3) might be the best protocol for reducing BSCVA (65.22%) but worst protocol for reducing MRSE (51.53%). aCXL with 18mW/cm2 for 5min (aCXL-5) might be the best protocol for reducing Kmax (39.58%) and MRSE (77.85%) but might be the worst for preserving ECD (50.98%). aCXL with 9mW/cm2 for 10min (aCXL-10) might be the best protocol for preserving ECD (31.53%). Overall, three protocols of aCXL are comparable in therapeutic efficacy and safety for treating progressive keratoconus. Despite no direct data comparing the efficacy of each technique according to different patients' profiles, it is reasonable to state that aCXL-5 may be the best for patients at early-stage to reduce Kmax and MRSE, aCXL-3 may be the best for patients at mid-stage to improve BSCVA, and aCXL-10 may be the best for patients at late-stage to preserve DEC.

Wavefront-guided PRK treatment of myopia using a refractive aberrometer.

To evaluate the safety, effectiveness, and patient-reported outcomes of wavefront-guided photorefractive keratectomy (PRK) for the correction of myopic refractive errors with and without astigmatism. U.S. multicenter study. Prospective, nonrandomized clinical investigation. 334 eyes (167 patients) underwent wavefront-guided PRK with the STAR S4 IR Excimer Laser System. Patients had preoperative myopic refractive errors with sphere up to -8.00 diopters (D) and cylinder up to -4.00 D with a maximum spherical equivalent (SE) of -10.00 D. All eyes were targeted for emmetropia, and treatment plans were derived from the iDESIGN system wavefront measurements. At 6 months, the point of refractive stability, 99.4% of eyes achieved 20/20 or better uncorrected distance visual acuity (UDVA), 92% of eyes achieved 20/16 or better UDVA, 85.5% of eyes achieved manifest refraction SE (MRSE) within 0.50 D of target, mean SE was -0.06, and less than 1% of eyes lost more than 2 lines of corrected distance visual acuity. Glare and halos occurred with similar or lower frequencies at 6 months vs preoperative. Results from the National Eye Institute Refractive Error Quality of life questionnaire showed statistically significant improvements at 6 months vs preoperative across most measures of vision-related functioning and well-being. Approximately 98% of patients reported high satisfaction with their overall vision at 6 months. Wavefront-guided PRK with the iDESIGN aberrometer was safe, effective, and predictable for the correction of low to moderate myopia with and without astigmatism and led to high patient satisfaction.

Clinical Outcomes After Bilateral Implantation of a Diffractive Trifocal Intraocular Lens: A Worldwide Pooled Analysis of Prospective Clinical Investigations.

To investigate visual and safety outcomes of AcrySof® IQ PanOptix® (model TFNT00), a trifocal, presbyopia-correcting intraocular lens (IOL), in patients of different ethnicities across multiple countries, based on a pooled analysis of six prospective multicenter studies. This pooled analysis included adult patients from six prospective clinical studies performed across 56 centers worldwide. After cataract removal by phacoemulsification, all patients were implanted with TFNT00; follow-up duration varied from 3 to 12 months according to the studies' design. Binocular defocus curve; absolute manifest refraction spherical equivalent (MRSE); and binocular photopic uncorrected and corrected visual acuities at distance (UCDVA, BCDVA; 4-5 m), intermediate (UCIVA, DCIVA; 60-66 cm), and near (UCNVA, DCNVA; 40 cm) were measured. The study included 557 patients, 547 of whom were implanted bilaterally with the TFNT00 IOL (n = 1094 eyes). Binocular visual data at 1 month and 3-6 months after implantation were available for up to 546 and 542 bilaterally implanted patients, respectively. A continuous range of 0.1logarithm of the minimum angle of resolution (logMAR) or better vision from distance (0.00 diopter [D], 4-5 m) to near (-3.00D; optically equivalent to 33 cm) was observed 3-6 months after TFNT00 implantation. At 3-6 months, 88.2% of first eyes achieved an MRSE ≤0.50 D and 88.7% of second eyes achieved an MRSE ≤0.50 D. Overall, 99.3%, 92.3%, and 94.6% of patients bilaterally implanted with TFNT00 achieved binocular photopic BCDVA, DCIVA, and DCNVA of 0.14 logMAR or better, respectively. Ocular adverse device effects and secondary surgical interventions (SSIs) were infrequent. This global pooled analysis showed that TFNT00 provided a continuous range of 0.1 logMAR (~20/25 Snellen) or better vision from distance to 33 cm, with a low incidence of ocular adverse device effects and SSIs.

Clinical Performance of a Hydrophobic Acrylic Diffractive Trifocal Intraocular Lens in a Japanese Population.

In this study, clinical performance of a hydrophobic acrylic diffractive trifocal intraocular lens (IOL) with double C-loop haptics was evaluated in Japanese cataract eyes. Twenty-three patients had bilateral cataract surgery with the implantation of a trifocal IOL with double C-loop haptics. Postoperative examinations at 6months included assessing uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA) at 5m, uncorrected intermediate visual acuity (UIVA), distance-corrected intermediate visual acuity (DCIVA) at 80cm, uncorrected near visual acuity (UNVA) and distance-corrected near visual acuity (DCNVA) at 40cm. Binocular defocus, contrast sensitivity, spectacle independence, symptoms of photic phenomena and quality of vision (QOV) were also observed. Twenty-three patients received 46 IOLs binocularly. Manifest refraction spherical equivalent was - 0.227 ± 0.385 D (mean ± standard deviation) at 6months postoperatively. Binocular UDVA, binocular UIVA and binocular UNVA were - 0.101 ± 0.065, - 0.021 ± 0.079 and 0.022 ± 0.095 logMAR units, respectively. Binocular CDVA, binocular DCIVA and binocular DCNVA were - 0.151 ± 0.044, - 0.042 ± 0.067 and - 0.011 ± 0.080 logMAR, respectively. Binocular CDVA of 0.00 logMAR or better was obtained in the defocus from - 3.0 D until + 0.5 D. Only 8.7% of patients required the use of spectacles postoperatively. There were no symptoms of glare, halo and light disturbance in 78.3%, 56.5% and 69.6% of patients, respectively. QOV scores significantly improved postoperatively (P < 0.0001). The hydrophobic acrylic trifocal IOL with double C-loop haptics provides good visual performance at all distances and produces high spectacle independence rate and patient satisfaction. NCT04699266 (Clinicaltrials.gov).

Q-value customized versus wavefront-optimized ablation in femtosecond laser-assisted LASIK for myopia and myopic astigmatism: a prospective contralateral comparative study

BackgroundCorneal refractive surgery for myopia results in an oblate shift with increased postoperative aberrations inversely affecting the quality of vision. Aspheric ablation profiles have been introduced to minimize such a problem. The aim of this study was to compare changes in corneal asphericity, central and mid-peripheral pachymetry between the Q-value customized and the wavefront-optimized (WFO) ablation profiles. MethodsA prospective, comparative non-randomized fellow eye study was conducted. Eighty eyes of 40 eligible patients underwent femtosecond laser-assisted laser in situ keratomileusis for myopia and myopic astigmatism. In each patient, the more myopic eye was included in the custom-Q ablation experimental group and the other less myopic eye was included in the WFO control group. For the custom-Q group, the target asphericity was set to the preoperative Q-value. Corneal asphericity, central and mid-peripheral pachymetric changes and the root mean square of corneal higher-order aberrations (RMSh) were assessed 6 months following surgery. Visual and refractive outcomes were also evaluated in both platforms 6 months postoperatively.ResultsThe mean preoperative refractive spherical equivalent was significantly more myopic in the custom-Q group than in the WFO group (P = 0.001). The mean Q-value changed from − 0.2 ± 0.1 to 0.6 ± 0.7 and from − 0.2 ± 0.1 to 0.4 ± 0.5 in the custom-Q and WFO groups, respectively. The oblate shift in corneal asphericity was not significantly different between both treatment groups (P = 0.094). The mean ablation depth at the pupillary center was significantly greater in the custom-Q group (P = 0.011), while there was no significant difference at the mid-peripheral pachymetry (P = 0.256). The RMSh significantly increased in both treatment profiles (P < 0.001) with no significant difference between the two groups (P = 0.06). The uncorrected distance visual acuity (UDVA) and the manifest refraction spherical equivalents (MRSE) significantly improved in both treatment groups (P < 0.001).ConclusionsThe custom-Q treatment profile with target asphericity set at the preoperative Q-value achieved comparable outcomes vs. the WFO profile in terms of postoperative corneal asphericity and mid-peripheral pachymetry despite the greater amount of ablation, the smaller optical zone, and the resulting increase in postoperative corneal flattening in the custom-Q group.Trial registration (Clinicaltrials.gov): NCT04738903, 4 February 2021- Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04738903

Comparison of two one-piece acrylic foldable intraocular lenses: Short-term change in axial movement after cataract surgery and its effect on refraction.

To compare the change in intraocular lens (IOL) axial movement, corneal power, and postoperative refraction of eyes implanted with two different single-piece, open loop, acrylic foldable IOLs with planar-haptic design: one IOL with hinges vs. one IOL without hinges. The role of IOL axial movement on short-term refractive shift after cataract surgery was also evaluated. This retrospective comparative study enrolled consecutive patients who had phacoemulsification with aspheric IOL implantation. The IOL depth (the distance from corneal endothelium to IOL surface) and corneal power were measured via anterior-segment optical coherence tomography at 4 days and 1 month postoperatively. The changes in axial movement of the IOL, corneal power, and manifest refractive spherical equivalent (MRSE) were compared among groups, and the correlations between each lens were evaluated. IOL with hinges was implanted in 42 eyes of 42 patients and IOL without hinges was implanted in 42 eyes of 42 patients. The change in axial movement between 4 days and 1 month was significantly smaller in the IOL with hinges group than in the IOL without hinges group (p < 0.001). The axial movement of IOL with hinges did not correlate with the MRSE change; however, the forward shift of IOL without hinges correlated with the myopic refractive change (Pearson r = 0.62, p < 0.001). The postoperative axial movement of IOL was more stable in the IOL with hinges group than the IOL without hinges group between 4 days and 1 month after cataract surgery. Even though the two study IOLs with planar-haptic design are made of similar acrylic materials, other characteristics such as hinge structure may affect IOL stability in the bag.

Outcomes of LASIK vs PRK enhancement in eyes with prior cataract surgery.

To compare postenhancement visual acuity between patients who underwent postcataract laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK). A private, tertiary referral practice in Sioux Falls, South Dakota. 3-year, retrospective chart review. Patients who underwent postcataract extraction excimer laser enhancement surgery targeted for emmetropia (±0.50 diopter). Postenhancement uncorrected distance visual acuity (UDVA) and manifest refraction spherical equivalent (MRSE) was recorded for all available follow-ups and compared for both groups. 822 postcataract enhanced eyes (491 LASIK; 331 PRK). For patients with at least 6-month follow-up, mean UDVA was 0.05 ± 0.13 logMAR in LASIK-enhanced patients and 0.15 ± 0.20 in PRK-enhanced patients ( P < .001). Mean absolute value MRSE was 0.22 ± 0.36 and 0.48 ± 0.62 for LASIK-enhanced and PRK-enhanced patients at or beyond 6 months, respectively ( P < .001). 330 (67%) LASIK-enhanced patients achieved 20/20 or better postenhancement UDVA, compared with 142 (43%) PRK-enhanced patients ( P < .001). Controlling for pre-enhancement UDVA, LASIK-enhanced patients showed significantly better postenhancement UDVA than PRK-enhanced patients, except in those with pre-enhancement vision of 20/20 or better, or those worse than 20/50. LASIK-enhanced virgin corneas had mean postenhancement of 0.05 ± 0.14 UDVA compared with 0.13 ± 0.19 UDVA in PRK-enhanced virgin cornea patients ( P < .001). LASIK provides better and more predictable outcomes in UDVA than PRK in postcataract enhancement patients, even when controlling for pre-enhancement visual acuity and prior ocular procedures.

Changes in Corneal Morphology and Biomechanics in Cases of Small Incision Lenticule Extraction with Prophylactic Accelerated Collagen Cross-Linking.

Purpose To study the corneal morphology and biomechanics in cases of small incision lenticule extraction with prophylactic accelerated collagen cross-linking (SMILE Xtra). Methods This study was a retrospective study. 28 eyes of 14 patients with moderate-high risk of postoperative ectasia according to the Randleman scoring system underwent SMILE Xtra procedure. Outcome data were recorded including uncorrected distance visual acuity (UDVA), manifest refraction spherical equivalent (MRSE), surface regularity index (SRI), surface asymmetry index (SAI), simulated keratometry (SimK), posterior axial curvature (PAC), anterior and posterior corneal elevations (ACE and PCE), central corneal thickness (CCT), corneal resistance factor (CRF), corneal hysteresis (CH), and cornea-compensated intraocular pressure (IOPcc). The follow-up period was 12 months. Results There were 28, 26, 22, 12, and 10 eyes enrolled at postoperative 1st day and 1st, 3rd, 6th, and 12th months, respectively. The UDVA improved from 1.27 ± 0.18 logMAR preoperatively to -0.06 ± 0.04 logMAR postoperatively (P < 0.05). The MRSE improved from -5.05 ± 1.15 D preoperatively to -0.14 ± 0.30 D postoperatively (P < 0.05). SAI, SimK, PAC, PCE, and CCT all changed significantly at 1st month postoperatively (P < 0.05) and stabilized during the remainder of the follow-up (P > 0.05). There was no significant change in SRI or ACE before and after surgery (P > 0.05). CRF, CH, and IOPcc all decreased significantly at 1st month postoperatively (P < 0.05) and remained stable afterwards (P > 0.05). Conclusions The changes in the corneal morphology and biomechanics remained stable after SMILE Xtra, and there was no sign of postoperative ectasia or refractive regression. Combined with the improvement of visual and refractive results, SMILE Xtra may be a promising method for corneal refractive surgeries in patients at risk.

Laser corneal enhancement after trifocal intraocular lens implantation in eyes that previously had photoablative corneal refractive surgery.

To evaluate the visual and refractive outcomes of laser corneal enhancement after trifocal intraocular lens (IOL) implantation in eyes previously treated with myopic/hyperopic laser corneal refractive surgery (LCRS). Clinica Baviera-AIER-Eye Group, Spain. Retrospective comparative case series. Patients were divided by primary LCRS into myopic and hyperopic groups. The outcomes evaluated were uncorrected distance (UDVA), corrected distance (CDVA), uncorrected intermediate (UIVA), and uncorrected near visual acuity (UNVA), and predictability, safety, efficacy, and satisfaction after implantation of 2 trifocal IOL models (Physiol-FineVision and Zeiss-ATLisa 839) and subsequent laser enhancement. 186 eyes (89 myopic and 97 hyperopic eyes) from 146 patients were assessed. At the last visit, refractive outcomes were better in myopic than those in hyperopic eyes, with statistically significant differences for sphere ( P < .001), cylinder ( P < .001), manifest refraction spherical equivalent (MRSE) ( P = .003), CDVA ( P = .005), UDVA ( P = .047), and UNVA ( P = .003) but not for UIVA ( P = .580), binocular UIVA ( P = .660), or binocular UNVA ( P = .836). Predictability differences were nonsignificant between groups for a final MRSE of ±0.5 diopters (D) and ±1.0 D (P = .167 and .502, respectively). Efficacy and safety were similar in both groups ( P = .235 and P = .080). A greater myopic MRSE was present after trifocal implantation in myopic than in hyperopic eyes (MRSE = -0.93 vs -0.69 D, P = .013), and the statistically significant differences were maintained after enhancement between both groups (MRSE -0.00 vs 0.00 D, P = .003). Overall satisfaction was similar in both groups ( P > .05 all items). Corneal laser enhancement after implantation of a trifocal IOL in eyes previously treated for myopia or hyperopia with LCRS was safe, effective, predictable, and highly satisfactory.

A prospective randomized self-controlled study of LASIK combined with accelerated cross-linking for high myopia in Chinese: 24-month follow-up

BackgroundTo assess the visual and refractive outcomes of femtosecond laser-assisted in situ keratomileusis (FS-LASIK) concurrent with accelerated cross-linking (LASIK Xtra) compared with conventional FS-LASIK (convLASIK) for high myopia in Chinese individuals.MethodsIn this prospective, randomized, fellow-eye comparison study, 25 patients with high myopia were treated randomly with LASIK Xtra in one eye and convLASIK in the other. A 24-month follow-up was conducted, and the main outcome measures included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE) and corneal tomography.ResultsThe UDVA was 0.09 ± 0.15 logMAR in the LASIK Xtra group, which was significantly worse than that in the convLASIK group 1 day postoperatively (P = .001), but the difference became nonsignificant from 1 week after surgery. The efficacy index was 0.88 ± 0.18 in the LASIK Xtra eyes and 0.99 ± 0.13 in the convLASIK eyes at 24 months (P = .028). Throughout the follow-up period, a slight myopic shift in the MRSE and keratometry values were observed in both groups without significant intergroup differences. The coefficient of determination was 0.9982 in the LASIK Xtra eyes and 0.9987 in the convLASIK eyes. The corneal density was significantly higher, and demarcation lines were visible in the first 6 months in LASIK Xtra eyes, but both signs of cross-linking gradually disappeared during follow-up. No severe complications were detected in either group.ConclusionsLASIK Xtra showed comparable safety and predictability with convLASIK for high myopia in Chinese, but lower efficacy and no greater stability was observed up to 24-month follow-up.

Comparison of Three Tonometers in Measuring Intraocular Pressure in Eyes That Underwent Myopic Laser in situ Keratomileusis and Photorefractive Keratectomy.

ObjectiveTo compare the intraocular pressure (IOP) obtained by Goldmann applanation tonometer (GAT), correcting applanation tonometer surface (CATS) and biomechanically corrected IOP (bIOP) of Corvis ST tonometer (CVS); and to determine the effects of manifest refraction spherical equivalent (MRSE), central corneal thickness (CCT) and mean corneal curvature (Km) on the IOP measurements of corneal refractive patients.MethodsThis was a single-center, retrospective, cross-sectional study of 120 eyes of 64 patients from May 1, 2020 to June 1, 2021 who underwent laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK). The level of agreement between the three tonometers was evaluated, and correlation between parameters was calculated using Pearson correlation.ResultsMean preoperative to postoperative IOP in LASIK and PRK was 15.1 ± 3 to 11.3 ± 2.1 and 14.4 ± 2.6 to 12.1 ± 3 using GAT, 16.4 ± 2.8 to 13.1 ± 2.3 and 15.9 ± 2.6 to 13.7 ± 3 using CATS and 14.8 ± 2.4 to 12.9 ± 1.5 and 14.2 ± 2.4 to 12.6 ± 1.9 using CVS-bIOP. Preoperative IOP correlation between each tonometer pair showed that the lowest mean difference was between GAT and CVS-bIOP (0.32 in LASIK, 0.15 in PRK). Preoperative to postoperative IOP correlation of each tonometer resulted in a difference of 3.77, 2.30 in GAT; 3.32, 2.28 in CATS and 1.88, 1.62 in CVS-bIOP in the LASIK and PRK groups, respectively. Percentage change in CCT and Km was not correlated while change in MRSE had a weak relationship with percentage change in CVS-bIOP.ConclusionPreoperatively, GAT and CVS-bIOP had the best agreement in IOP measurements. CATS recorded the highest IOP preoperatively and postoperatively. IOP decreased in the three tonometers after LASIK and PRK with GAT having the largest decrease. CVS-bIOP had the lowest change between preoperative and postoperative IOP measurements. Only percentage change in MRSE was correlated with percentage change in CVS-bIOP in the LASIK group.

Femtosecond laser-assisted in situ keratomileusis with topography-guided or asphericity-adjusted derived data: a comparative contralateral eye study

BackgroundWavefront-optimized laser-assisted in situ keratomileusis (LASIK) ablation is the most commonly performed procedure in refractive surgery, but new technologies have become available. Our goal was to compare topography-guided (Contoura) and asphericity-guided (Custom-Q) customized ablation treatments for the correction of myopia with or without astigmatism.MethodsThis prospective, randomized, double-blind, contralateral eye study included 60 eyes of 30 patients with myopia or myopic astigmatism requiring femtosecond LASIK (FemtoLASIK) treatment. For each patient, one eye was randomized to undergo Contoura treatment, and the other underwent Custom-Q abaltion. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refractive spherical equivalent (MRSE), sphere (SPH), cylinder (CYL), 6.0-mm total corneal aberration root mean square (RMS), coma (COMA), trefoil (TREF), and spherical aberration (SA) were measured and analysed after a 1-year follow-up.ResultsThe UDVA was − 0.08 ± 0.06 logMAR in Contoura eyes and − 0.08 ± 0.05 logMAR in Custom-Q eyes (p = 0.309) after 12 months. Twenty-five eyes (83%) in the Contoura group and twenty-six eyes (87%) in the Custom-Q group had a UDVA of 20/16 at the end of 12 months, and 100% of eyes in both groups reached a UDVA of 20/25 or better. Ninety and 100% of eyes in the Contoura and Custom-Q groups, respectively, achieved a residual CYL ≤0.50 D (p = 0.237). No statistically significant difference was observed between the surgical techniques in the preoperative to 1-year postoperative changes for any of the parameters evaluated (MRSE, CYL, RMS, DEF, COMA, TREF, and SA).ConclusionsThe Contoura and Custom-Q techniques yielded excellent visual and refractive results, but the evidence did not reveal any clear differences between these two methods after 1 year of follow-up.Trial registrationReBEC - Registro Brasileiro de Ensaios Clínicos [Internet]: Rio de Janeiro (RJ): Instituto de Informação Científica e Tecnológica em Saúde (Brazil); 2010 -. Identifier RBR-8rs5kt Myopia and Astigmatism Topography-guided Refractive Surgery by Contoura Method Versus Customized by Asphericity in Contralateral Eyes: A prospective Double blind Randomized Study. Available from https://ensaiosclinicos.gov.br/rg/RBR-8rs5ktDate of registration: 02/03/2020 (dd/mm/yyyy).CAAE:96778718.9.0000.5192.Issuing authority: Plataforma Brasil.CEP:2.979.279.Issuing authority: HUOC.

A Prospective, Randomized, Double-Masked Controlled Clinical Trial of Postoperative Pain after Transepithelial Photorefractive Keratectomy (Trans-PRK).

Objective To determine the effect of aqua astricta flushing on ocular pain after Trans-PRK. Method Three hundred and seventy eyes from 185 myopic patients were prospectively recruited for the study. Patients underwent Trans-PRK in both eyes. Postsurgically, one eye from each patient was randomly assigned to the trial group, and refrigerated normal saline was used to rinse the eye. The contralateral eye was assigned to the control group, and room temperature normal saline was used to rinse the eye. The primary target was postoperative pain experienced at the end of surgery and on the first, second, and third days after surgery. Secondary targets were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refractive spherical equivalent (MRSE), and haze. Results Patient pain scores gradually decreased over time, and the difference between time points of all patients was statistically significant (P < 0.05). Postoperative pain was not affected by patient cooperation, education level, refractive SE, optical zone, corneal bed, or cutting depth (P > 0.05). The level of pain at the end of surgery was affected by intraoperative rinsing. The pain level of the aqua astricta group was lower than the normal temperature saline group, and the difference was statistically significant (P < 0.01). Pain scores on the first, second, and third days after surgery were not affected by intraoperative rinse (P > 0.05). Conclusion Trans-PRK is an important means of corneal refractive surgery, but postoperative pain remains unavoidable. These findings suggest that the use of cooled fluid during surgery reduces postoperative pain at the end of surgery.