logMAR Uncorrected Distance Visual Acuity Research Articles

Prevalence of visual impairment and estimation of refractive errors among school children in Kakamega, Kenya.

To investigate the prevalence of visual impairment (VI) and provide an estimation of uncorrected refractive errors in school-aged children, conducted by optometry students as a community service. The study was cross-sectional. Totally 3343 participants were included in the study. The initial examination involved assessing the uncorrected distance visual acuity (UDVA) and visual acuity (VA) while using a +2.00 D lens. The inclusion criteria for a subsequent comprehensive cycloplegic eye examination, performed by an optometrist, were as follows: a UDVA<0.6 decimal (0.20 logMAR) and/or a VA with +2.00 D ≥0.8 decimal (0.96 logMAR). The sample had a mean age of 10.92±2.13y (range 4 to 17y), and 51.3% of the children were female (n=1715). The majority of the children (89.7%) fell within the age range of 8 to 14y. Among the ethnic groups, the highest representation was from the Luhya group (60.6%) followed by Luo (20.4%). Mean logMAR UDVA choosing the best eye for each student was 0.29±0.17 (range 1.70 to 0.22). Out of the total, 246 participants (7.4%) had a full eye examination. The estimated prevalence of myopia (defined as spherical equivalent ≤-0.5 D) was found to be 1.45% of the total sample. While around 0.18% of the total sample had hyperopia value exceeding +1.75 D. Refractive astigmatism (cil<-0.75 D) was found in 0.21% (7/3343) of the children. The VI prevalence was 1.26% of the total sample. Among our cases of VI, 76.2% could be attributed to uncorrected refractive error. Amblyopia was detected in 0.66% (22/3343) of the screened children. There was no statistically significant correlation observed between age or gender and refractive values. The primary cause of VI is determined to be uncorrected refractive errors, with myopia being the most prevalent refractive error observed. These findings underscore the significance of early identification and correction of refractive errors in school-aged children as a means to alleviate the impact of VI.

Efficacy comparison of combining cross-linking and refractive laser ablation in progressive keratoconus: systematic review and meta-analysis

ObjectiveThis study assessed the effect of combining corneal collagen cross-linking (CXL) with refractive laser ablation techniques for the treatment of keratoconus, a progressive corneal disorder. MethodsWe performed a systematic review and meta-analysis to assess the effect of combined CXL and refractive techniques. We included all published clinical trials or observational studies published by September 1, 2023. We calculated and compared the standardized mean difference (SMD) between CXL alone and CXL plus laser ablation for uncorrected distance visual acuity, best-corrected distance visual acuity, spherical equivalent manifest refraction, sphere and cylinder, flat keratometry (K1), steep keratometry (K2), and central corneal thickness. ResultsWe identified 13 studies that fulfilled our inclusion and exclusion criteria. The average follow-up was 21.3 ± 11.8 months. The CXL plus laser ablation group showed improvement in uncorrected distance visual acuity logMAR (SMD, –0.35; 95% CI, –0.67 to –0.04; p = 0.029), best-corrected distance visual acuity logMAR (SMD, –0.17; 95% CI, –0.30 to –0.03; p = 0.014), spherical equivalent manifest refraction (SMD, –0.28; 95% CI, 0.06–0.50; p = 0.013), and change in maximal corneal curvature (Kmax; SMD, –0.41; 95% CI, –0.69 to –0.13; p = 0.004) compared with CXL alone. However, central corneal thickness decreased further among patients who underwent CXL plus laser ablation (SMD, –0.37; 95% CI, –0.66 to –0.07; p = 0.016). No effect was observed in terms of sphere (p = 0.878), cylinder (p = 0.859), K1 (p = 0.907), or K2 (p = 0.169). Ectasia was not observed as an adverse effect resulting from the additional corneal ablation performed during the CXL treatments. ConclusionsThis study showed that combining refractive laser ablation techniques with standard or accelerated CXL treatment improved visual and refractive outcomes and anterior corneal curvature values.

Tear Film Stability Affects Visual Acuity After Implantations of Monofocal and Multifocal Intraocular Lenses: An Evaluation by Objective Scatter Index.

To assess the impact of tear film on postoperative visual acuity after cataract surgery to implant an intraocular lens (IOL). Tear break-up time (TBUT), Schirmer I test, objective scatter index (OSI), and uncorrected distance visual acuity (UCDVA), intermediate visual acuity (UCIVA), and near visual acuity (UCNVA) were collected 6months after cataract surgery. Fifteen eyes with monofocal (Mo-) IOLs and 15 eyes with multifocal (Mu-) IOLs from 30 subjects were included. The Mu-IOL group exhibited higher baseline OSI (1.92 ± 0.69, P < 0.001). Negative correlations-both groups: tear film-related OSI (TF-OSI) and TBUT/Schirmer I test; Mo-IOL: TBUT and logMAR UCDVA-and positive correlations-both groups: TF-OSI and baseline OSI, baseline OSI/TF-OSI and logMAR UCDVA; Mu-IOL: baseline OSI/TF-OSI and logMAR UCIVA/UCNVA-were found. Linear regression showed associations between TF-OSI and TBUT (Mo-IOL: R2=0.455, P=0.006; Mu-IOL: R2=0.454, P=0.006)/Schirmer I test (Mo-IOL: R2=0.527, P=0.002; Mu-IOL: R2=0.266, P=0.049). Multiple regression showed associations between baseline OSI (Mo-IOL: R2=0.309, P=0.032; Mu-IOL: R2=0.305, P=0.033)/TF-OSI (Mo-IOL: R2=0.332, P=0.025; Mu-IOL: R2=0.523, P=0.002)/TBUT (Mo-IOL only: R2=0.315, P=0.029) and logMAR UCDVA. TF-OSI reflects the UCDVA performance in eyes with IOLs and facilitates a better understanding of the effects of the tear film. TF-OSI offers a developmental and objective approach to assessing the changing visual performance caused by tear film after cataract surgery and IOL implantation in clinical practices.

Outcomes of preloaded toric intraocular lens implantation in eyes undergoing phacoemulsification.

To evaluate the clinical outcomes of preloaded toric intraocular lens (IOLs) implantation in eyes undergoing phacoemulsification. This prospective study included 51 eyes of 51 patients with visually significant cataracts and corneal astigmatism ranging between 0.75 and 5.50 D. All patients underwent phacoemulsification with SupraPhob toric intraocular lens implantation under topical anesthesia. The main outcome measures were uncorrected distance visual acuity (UDVA), residual refractive cylinder, spherical equivalent, and IOL stability at 3 months follow-up. At 3 months, 49% (25/51) of patients had UDVA equal to or better than 20/25 with 100% of eyes achieving better than 20/40. Mean logMAR UDVA improved from 1.02 ± 0.39, preoperatively to 0.11 ± 0.10 at 3 months follow-up (P < 0.001, Wilcoxon signed-rank test). The mean refractive cylinder improved from - 1.56 ± 1.25 D preoperatively to - 0.12 ± 0.31 D at 3 months follow-up (P < 0.001) while the mean spherical equivalent value changed from - 1.93 ± 3.71D preoperatively to - 0.16 ± 0.27D (P = 0.0013). The mean root mean square value for higher order aberrations was 0.30 ± 0.18 μm while the average contrast sensitivity value (Pelli-Robson chart) was 1.56 ± 0.10 log unit, at the final follow-up. The mean IOL rotation at 3 weeks was 1.7 ± 1.61 degrees, which did not change significantly at 3 months (P = 0.988) follow-up. There were no intraoperative or postoperative complications. SupraPhob toric IOL implantation is an effective method for addressing preexisting corneal astigmatism in eyes undergoing phacoemulsification with good rotational stability.

Crosslinking for post-laser-assisted in situ keratomileusis corneal ectasia: Transepithelial flap-on 30 minute and flap-lift 4 minute protocol.

To evaluate the outcomes of transepithelial corneal collagen crosslinking (CXL) for management of corneal ectasia after laser-assisted in situ keratomileusis (LASIK). CXL was performed on 18 eyes of 16 patients either with LASIK flap lift (n = 9; 365 nm, 30 mW/cm2, 4 minutes, pulse) or with transepithelial flap-on (n = 9 eyes; 365 nm, 3 mW/cm2, 30 minutes) technique. Postoperative change in maximum keratometry (Kmax), anterior elevation, posterior elevation, spherical equivalent (SE), logMAR uncorrected distance visual acuity (UDVA), aberrations, and central corneal thickness (CCT) were evaluated at 12 months postoperatively. A total of 18 eyes of 16 patients (11 males, 5 females) were included. Overall, Kmax flattened more after flap-on CXL (P = 0.014) compared to flap-lift CXL. The endothelial cell density and posterior elevation were stable throughout the follow-up period. Index of vertical asymmetry (IVA), keratoconus index (KI), and central keratoconus index (CKI) decreased after flap-on CXL at 12 months, postoperatively (P < 0.05), whereas there were no statistically significant changes in these parameters after flap-off CXL group. The spherical aberrations and total root mean square decreased after flap-lift CXL at 12 months, postoperatively (P < 0.05). In our study, transepithelial collagen crosslinking was successfully used to halt disease progression in post-LASIK keratectasia. We recommend flap-on surgical technique for these cases.

Combined simultaneous photorefractive keratectomy and collagen cross-linking in keratoconus suspect patients

To evaluate the safety and efficacy of combined simultaneous photorefractive keratectomy (PRK) with collagen cross-linking (CXL) in keratoconus suspects (KCS). This was a retrospective, non-randomized study of KCS patients who underwent combined simultaneous PRK with CXL. The efficacy, safety, refractive outcomes, and corneal wavefront aberration changes were assessed after the surgery and compared with existing preoperative data. Fifty-six eyes of 28 patients, including 20 females (71.4%), with a mean age of 30.92±4.09 years, were enrolled. The mean follow-up was 19.46±8.48 months (range: 7-35). At the conclusion of the study, mean uncorrected distance visual acuity LogMAR improved from 0.89±0.44 preoperatively to 0.04±0.09 postoperatively (P<0.001). In addition, a statistically significant corneal flattening was observed postoperatively, with a decrease in manifest refraction. A statistically significant increase was found in higher-order aberrations (P<0.001), horizontal coma (P<0.001), and spherical aberration (P<0.001) compared with preoperatively. Postoperatively, 41% exhibited refractive astigmatism of 0.50 diopter (D) or less; 83.8% showed 1.00 D or less. The results of our study indicate that combined simultaneous PRK with CXL can be a safe and effective method for treating refractive instability in KCS patients.

Combined corneal wavefront-guided transepithelial photorefractive keratectomy and accelerated corneal collagen cross-linking following intracorneal ring segment implantation in management of moderate keratoconus.

PURPOSE:Keratoconus (KC) leads to gradual progressive loss of vision in young and adult patients. For the purpose of visual rehabilitation and for hindering KC progression in patients, we designed this study. The main aim of this study is to help the KC patients to improve and stabilize their vision.METHODS:This prospective consecutive uncontrolled study includes 36 eyes of 36 patients with moderate degree of KC. All patients underwent combined wavefront-guided transepithelial photorefractive keratectomy (TPRK) and accelerated corneal collagen cross-linking (ACXL) after intracorneal ring segment (ICRS) implantation. Different measures will be evaluated at baseline, after ICRS implantation, and at one, 3, 6, and 12 months after combined (TPRK and ACXL). These measurements are uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), corneal indices based on Scheimpflug tomography, and higher-order aberrations (HOAs) based on (Sirius, Schwind) tomography.RESULTS:There were significant improvements in logMAR (UDVA and CDVA) and reduction in sphere, manifest cylinder, MRSE, maximal keratometry, and mean keratometry after ICRS implantation in the first stage. After TPRK and ACXL as the second stage, there were significant improvements in visual acuity of both logMAR UDVA and CDVA. Reduction in refractive outcomes, including MRSE, sphere, and manifest cylinder. All corneal indices including steep, flat, mean, and maximal keratometries had been decreased. Furthermore, there were significant improvements in the final root mean square, HOAs, and coma aberrations from baseline.CONCLUSION:In moderate KC, triple therapy of ICRS implantation followed by combined TPRK and ACXL appears to be a safe and effective approach. This approach provides an improvement in visual acuity, refraction, corneal indices, and HOAs. These improvements were maintained for 1 year postoperatively. It also halts KC progression.

Refractive Outcomes of Implantable Collamer Lens Implantation in 1212 Eyes with Suboptimal Corrected Distance Vision Acuity

Purpose To analyze the factors related to corrected distance vision acuity (CDVA) after implantable collamer lens (ICL) implantation in patients with preoperative suboptimal CDVA. Methods This retrospective study included patients with suboptimal preoperative CDVA (CDVA ≤ 20/25) who underwent ICL implantation (V4 or V4c). Preoperative and postoperative clinical evaluations included CDVA, uncorrected distance visual acuity (UDVA), and refraction. Results A total of 1212 eyes from 731 patients were identified. CDVA increased in 90.8% of the eyes after surgery. Among them, 57.5% of the eyes (697 eyes) gained more than one line. The preoperative LogMAR CDVA was 0.32 ± 0.23, which significantly improved to 0.13 ± 0.17 postoperatively (p < 0.001). There was no significant difference between ICL V4c and ICL V4 in the LogMAR UDVA, sphere, cylinder, SE, LogMAR CDVA, efficacy index, and safety index after surgery (p > 0.05). For eyes with full correction, the postoperative LogMAR CDVA = 0.575 * preoperative LogMAR CDVA − 0.061 (p < 0.001, R 2 = 0.53). For eyes with partial correction, the postoperative LogMAR CDVA = 0.536 * preoperative LogMAR CDVA − 0.007 * SE - 0.196 (p < 0.001, R 2 = 0.55). Conclusions ICL implantation can improve CDVA in eyes with suboptimal CDVA. This study provides the postoperative outcomes of eyes with different preoperative CDVA, which makes it convenient for surgeons to communicate with such patients before surgery.

Effect of eye laterality on correction of myopic astigmatism with small incision lenticule extraction (SMILE) using vector analysis.

To compare the vector analysis, visual, and refractive outcomes after myopic astigmatic correction using SMILE between the right and left eyes. This is a retrospective study including 41 right and 40 left eyes that underwent SMILE for correction of myopic astigmatism greater than 0.75 diopters (D) with a follow-up of at least 3months. Vector analysis for astigmatic correction was done. Visual and refractive parameters were compared between both groups by measuring mean postoperative logMAR uncorrected distance visual acuity, mean postoperative spherical equivalent (SE), cylinder, and refractive predictability in terms of SE and cylindrical correction. Efficacy and safety of SMILE were also determined. No significant difference was found between vector outcomes except for angle of error (AE). The right eye group yielded a negative mean AE (- 2.71 ± 5.35), while the left eye group yielded a positive mean AE (0.23 ± 9.60). Correction index, magnitude of error and refractive predictability of cylindrical correction showed undercorrection of astigmatism in both groups. The right eye group showed lower predictability for higher cylindrical correction. Visual outcomes were similar for both eyes. Rotational errors account for vectorial outcome differences between right and left eyes. Despite achieving good visual and refractive outcomes with low cylinder correction, the tendency to undercorrect between eyes due to this error may be more evident when treating higher amounts of astigmatism. More careful preoperative control for cyclotorsion is warranted for right eyes compared to left eyes.

Comparison of the clinical outcomes of Eyecryl™ and Tecnis® toric intraocular lenses: A real-world study.

Purpose:To compare the postoperative uncorrected distance visual acuity (UDVA) and refractive outcomes of cataract patients with astigmatism following implantation of Eyecryl™ and Tecnis® toric intraocular lenses (IOLs).Methods:We conducted a single-center, retrospective study including patients who had undergone phacoemulsification and implantation with either Eyecryl™ toric (Group 1) or Tecnis® toric (Group 2) IOL. The primary outcome measures included postoperative UDVA and residual astigmatism at 3 months. The secondary outcome measure was IOL misalignment >10° throughout the follow-up period.Results:One hundred and eight eyes of 76 patients (44 males and 32 females) were analyzed. Twenty-nine patients (38 eyes) received Eyecryl™ toric IOL (Group 1), and 47 patients (70 eyes) received Tecnis® toric IOL (Group 2). Groups 1 and 2 showed a mean postoperative logMAR UDVA of 0.09 ± 0.11 and 0.06 ± 0.09, respectively, at 3 months (P = 0.114). In both groups, all the eyes achieved a postoperative UDVA of ≤0.3 logMAR. The postoperative residual astigmatism of group 1 and group 2 was -0.29 ± 0.34 D and -0.16 ± 0.27 D, respectively (P = 0.038). Postoperative astigmatism was within ± 1.00 D in all the eyes. No eyes had an IOL misalignment >10° throughout the follow-up period.Conclusion:Both Eyecryl™ and Tecnis® toric IOLs provided significant improvement in uncorrected visual acuity and astigmatism correction postoperatively. The Tecnis® toric IOL provided statistically significant lower residual astigmatism than Eyecryl™toric IOL. However, the difference in postoperative astigmatism between the two IOLs was clinically insignificant.

Twelve-Month Outcomes of the Wavefront-Optimized Photorefractive Keratectomy for High Myopic Correction Compared with Low-to-Moderate Myopia.

PurposeTo evaluate the 12-months outcomes of photorefractive keratectomy (PRK) in patients with high myopia (≥ 6.0 diopters, D) compared with low-to-moderate myopia (< 6.0 D).Patients and MethodsRecords of 46 patients (69 eyes) who underwent PRK for myopic and astigmatic correction between October 2015 and December 2018 were reviewed. High myopic eyes (29 eyes) were compared with low-to-moderate myopic eyes (40 eyes). All surgeries were adjunct with 0.02% mitomycin C intraoperatively. Measured outcomes included postoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent, corneal haze rate, and any complications.ResultsAt 12 months post-PRK, 26 eyes (89.7%) in the high myopia and 39 eyes (97.5%) in the low-to-moderate myopia group had UDVA ≥ 20/20, (p=0.30). Average postoperative logMAR UDVA at 12 months was −0.04 (20/18) and −0.11 (20/15) for the high myopia and low-to-moderate myopia groups, respectively. No eyes in either group had residual refractive errors >1 D. No eyes in both groups developed significant corneal haze at month 12. No eyes had a loss of greater than two Snellen lines of CDVA at 12 months post-surgery. The efficacy and safety indices at 12 months post-surgery were not significantly different between groups (1.06±0.26 vs.1.14±0.27, p =0.25 and 1.14±0.27 vs 1.17±0.26, p=0.60 for low-to-moderate myopia vs high myopia groups, respectively).ConclusionPRK with high myopic correction provides excellent refractive outcomes and is safe, compared to those of low-to-moderate myopic correction.

A One Year Longitudinal Comparative Analysis of Visual Outcomes Between Femtosecond Laser-Assisted Cataract Surgery and Standard Phacoemulsification Cataract Surgery.

PurposeTo assess visual outcomes over time of femtosecond laser-assisted cataract surgery compared to standard phacoemulsification cataract surgery.DesignA retrospective, single-center comparative study.MethodsPatient data including demographics, ocular biometry, pre- and postoperative visual acuity, postoperative complications, primary (uncorrected distance visual acuity over time) and secondary visual outcomes (uncorrected near visual acuity, best distance visual acuity, patient complaints, satisfaction, and postoperative surgery) were gathered and statistically analyzed. Demographic differences between patients receiving femtosecond-laser assisted cataract surgery (FLACS) versus standard phacoemulsification cataract surgery (PCS) were corrected for outcome comparison. Safety, efficacy, predictability, and stability were analyzed for each procedure and compared.ResultsA total of 155 eyes in PCS and 143 eyes in FLACS were analyzed at 1 week, 3 months, and 1 year using odds ratio. The odds ratio of being 20/20 or better and 20/40 or better at the specified time periods were similar and statistically insignificant at all time periods analyzed except 20/20 or better for uncorrected distance visual acuity (UDVA) at 1 year (p=0.0001) and uncorrected near visual acuity (UNVA) at 1 week (p=0.02). In both cases, the odds of being 20/20 or better favored FLACS. Mean UDVA, UNVA, and best distance visual acuity (BDVA) were all similar and statistically insignificant between the two groups. Postoperative patient complaints, safety, efficacy, predictability, and stability between the two groups showed no statistical significance.ConclusionDespite the odds ratio of being 20/20 or better favoring FLACS for UDVA at 1 year and UNVA at 1 week, the mean logMAR UDVA, BDVA, and UNVA were similar and statistically insignificant between the FLACS and PCS groups at 1 week, 3 months, and 1 year. Differences in visual acuity were likely due to differences other than surgical approaches. While both FLACS and PCS are appropriate approaches to cataract surgery, one does not appear to be superior when assessing longitudinal markers for visual acuity, safety, efficacy, predictability and stability.

3-month surgical outcomes of Implantable Collamer Lens implantation for myopic regression after laser vision correction surgeries: a retrospective case series

BackgroundTo investigate the surgical outcomes of implantable collamer lens (ICL) implantation in eyes with residual myopia after primary laser vision correction (LVC) surgeries.MethodsThis study included patients who underwent ICL implantation and had a history of LVC surgery, including photorefractive keratectomy (PRK) or laser-assisted in situ keratomileusis (LASIK). Visual acuity and refractive error were assessed pre and 3-months postoperatively and the efficacy and safety indices calculated accordingly.ResultsA total of 30 eyes of 17 patients were included in this study. At 3 months, the mean logMAR uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and spherical equivalent were − 0.03 ± 0.11 (include logMAR), − 0.04 ± 0.09 (include logMAR), and − 0.06 ± 0.33 diopters (D), respectively. The 3-month Snellen UDVA was better than 20/20 for 83% of eyes, and 97% of eyes showed an unchanged or improved CDVA after surgery. The mean efficacy and safety indices were 1.11 ± 0.22 and 1.13 ± 0.20, respectively. Further, 93 and 100% of eyes were within ±0.5 and ± 1.0 D of the attempted spherical equivalent refraction, respectively.ConclusionsICL implantation in eyes with myopic regression after previous LVC surgery showed safe, effective, and predictable outcomes.Trial registrationretrospectively registered.

Accelerated versus Standard Corneal Cross-linking for Progressive Keratoconus in Syria.

PurposeTo compare the outcomes of accelerated versus standard corneal cross-linking for the treatment of progressive keratoconus.Methods In this retrospective comparative study, 63 eyes of 40 patients with progressive keratoconus were divided into two groups; 27 eyes in group one were treated with an accelerated protocol (10 mW/cm, 9 min) and 36 eyes in group two were treated with the standard method (3 mW/cm, 30 min). Visual acuity, refraction, corneal topography, corneal tomography, and anterior and posterior corneal higher-order aberrations (HOAs) were assessed preoperatively and 18–30 months postoperatively.ResultsThe LogMAR uncorrected and corrected distance visual acuity values were improved in both groups postoperatively. However, the improvement was significantly higher in group one (P 0.05, all). The flattening in the anterior keratometry readings, flat K, steep K, and average K were significantly higher in group two (P 0.001, all). The maximum anterior keratometry (AKf) values significantly decreased in both groups, whereas the maximum posterior keratometry (AKb) values increased. The reduction in the minimum corneal thickness (ThKmin) was significantly greater (36.49um) in group two, compared to 10.85um in group one. There was a significant increase in the posterior average keratometry, and a significant decrease in the posterior astigmatism, along 3 mm meridian in S-CXL (P = 0.03, P = 0.008, respectively), while the corresponding values showed no statistical significance in group one (P 0.05). The anterior corneal trefoil was significantly reduced in group one (P = 0.002), whereas anterior total HOAs and coma were significantly improved in group two (P 0.0014, all). The posterior corneal spherical aberration decreased significantly in group one (P = 0.02), while group two revealed significant reduction in the posterior trefoil values (P = 0.011). The change in the anterior maximum keratometry was significantly and positively correlated to the preoperative maximum keratometry in group two (P = 0.53, P = 0.003).ConclusionAn accelerated cross-linking protocol using 10 mW/cm for 9 min showed more visual improvement and less pachymetric reduction when compared to the standard protocol, however, anterior corneal flattening, posterior corneal steepening, and the change in the posterior astigmatism were significantly higher in the standard protocol; while corneal HOAs were improved in both protocols.

Long term results of accelerated corneal collagen cross-linking in pediatric keratoconus

To evaluate the long term visual, refractive, and corneal tomographic outcomes of epithelium-off accelerated corneal collagen cross-linking (ACXL) in the management of pediatric keratoconus (KC). This retrospective study included patients under 18 years old with progressive KC who underwent ACXL between 2012 and 2019 at Dicle University Hospital. Complete ophthalmic examination was performed including uncorrected distance visual acuity (UDVA), best spectacle-corrected distance visual acuity (CDVA), manifest refraction, and corneal tomography. Evaluations were performed preoperatively and at 6 months intervals postoperatively. Forty-nine eyes of 49 patients were included in the study. The mean age of patients at the time of ACXL was 14.2 ± 1.8 (range: 9.5-17.3) years. Mean follow up was 4.61 ± 1.90 (range: 2.0-8.1) years. The mean LogMAR UDVA improved from 0.94 ± 0.41 to 0.81 ± 0.43, 0.69 ± 0.41, and 0.67 ± 0.33 after 1, 3, and 5 years respectively (p = 0.001). The mean LogMAR CDVA improved from 0.58 ± 0.36 to 0.46 ± 0.31, 0.34 ± 0.23, and 0.39 ± 0.27 after 1, 3, and 5 years respectively (p = 0.015). The mean refractive cylinder improved significantly from 6.01 ± 2.07 diopters (D) to 5.46 ± 1.87, 5.38 ± 2.18, and 5.02 ± 2.31 D after 1, 3, and 5 years respectively (p = 0.005). As compared to preoperative values, steep keratometry and maximum keratometry were not significantly different (p = 0.805 and 0.448, respectively) following ACXL, while flat keratometry significantly improved after ACXL (p = 0.012). Although central corneal thicknesses decreased significantly (p = 0.029), the decrease in thinnest corneal thickness was not statistically significant (p = 0.205). Epithelium-off ACXL seems to be effective for halting KC progression with long term clinical benefits in pediatric patients.

Clinical outcomes of simultaneous phototherapeutic keratectomy and photoastigmatic keratectomy

This study was aimed to assess the outcomes of simultaneous phototherapeutic keratectomy (PTK) and photoastigmatic keratectomy (PAK), with special attention to astigmatic correction. We comprised 70 eyes of 70 patients who underwent simultaneous PTK and PAK in patients having granular corneal dystrophy and band keratopathy with refractive astigmatism of 1 diopter (D) or more. Preoperatively and 6 months postoperatively, we assessed corrected uncorrected distance visual acuity (UDVA), distance visual acuity (CDVA), manifest spherical equivalent, refractive astigmatism, corneal astigmatism, and higher-order aberrations (HOAs). LogMAR CDVA significantly improved, from 0.27 ± 0.27 preoperatively, to 0.13 ± 0.21 postoperatively (Paired t test, p < 0.001). LogMAR UDVA also significantly improved, from 0.70 ± 0.32 preoperatively, to 0.57 ± 0.41 postoperatively (p = 0.043). Refractive astigmatism significantly decreased, from 2.12 ± 0.95 D preoperatively, to 0.89 ± 0.81 D postoperatively (p < 0.001). Corneal astigmatism also significantly decreased, from 2.17 ± 0.90 D preoperatively, to 1.08 ± 0.71 D postoperatively (p < 0.001). Corneal HOAs did not significantly change, from 0.54 ± 0.30 µm preoperatively, to 0.48 ± 0.20 µm postoperatively (p = 0.140). No significant complications occurred in any eye. Simultaneous PTK and PAK treatment is effective not only for improving visual acuity, but also for reducing astigmatism.

Long-term Results of a Combined Procedure of Cataract Surgery and Descemet Membrane Endothelial Keratoplasty With Stromal Rim.

To evaluate the long-term results of combining cataract surgery, intraocular lens (IOL) implantation, and Descemet membrane endothelial keratoplasty with peripheral stromal support (DMEK-S). The outcomes of 107 eyes of 37 patients who had undergone a combination of cataract surgery, IOL implantation, and DMEK-S between October 2007 and February 2015 were retrospectively evaluated. The average follow-up duration was 18.2 ± 18.3 months (range, 6-84 months). Changes in uncorrected and corrected distance visual acuity, spherical equivalent, and corneal endothelial cell density were analyzed. Intraoperative and postoperative complications were also recorded. The mean logMAR uncorrected distance visual acuity improved from 0.92 ± 0.60 preoperatively to 0.33 ± 0.33, 0.28 ± 0.25, 0.24 ± 0.20, and 0.27 ± 0.27 at 6, 12, 24, and 36 months postoperatively (P < 0.001), respectively. The mean logMAR corrected distance visual acuity improved from 0.62 ± 0.65 preoperatively to 0.17 ± 0.29, 0.13 ± 0.21, 0.07 ± 0.16, and 0.11 ± 0.23 at 6, 12, 24, and 36 months postoperatively (P < 0.001), respectively. The mean endothelial cell density decreases were 50.7% ± 21.1%, 50.8% ± 19.8%, 60.7% ± 16.6%, 62.2% ± 11.8%, and 61.8% ± 20.0% at 6, 12, 24, 36, and 48 months after surgery, respectively. Similar trends, although with slightly better visual outcomes, were found in the subgroup of patients without other eye diseases. The mean final deviation from intended spherical equivalent was 0.77 ± 1.19 D, representing a hyperopic shift. A combined procedure of cataract surgery, IOL implantation, and DMEK-S is an effective method of treatment in patients with combined corneal disease and cataract, maintaining visual rehabilitation in the long term. Future developments should be performed to minimize the incidence of complications.

Correlation and regression analysis between residual gradation and uncorrected visual acuity one year after refractive surgery with LASIK, FS-LASIK, PRK, PRK Xtra techniques and the implantation of ICL® posterior chamber phakic lens in myopic correction

To analyze the influence of the final spherical equivalent (SE) in LogMAR uncorrected distance visual acuity (UDVA) one year after refractive surgery. We analysed refractive results, their predictability and efficacy, and the safety results of the different methods as secondary outcomes. Refractive Surgery Unit of the Institut Català de Retina (ICR) in Barcelona, Spain. Retrospective, analytical observational study. Retrospective and observational study of 654 eyes of 327 patients who underwent refractive surgery to treat their myopia or myopic astigmatism using LASIK, FS-LASIK, PRK, PRK Xtra or ICL-type lens implantation surgery were included. The correlation between the SE in absolute value was statistically significant in all techniques utilized, reaching higher values in the FS-LASIK and LASIK techniques, 0.774 and 0.706 respectively, and lesser values in PRK (0.480) and PRK Xtra (0.482). A significant adjustment via a univariate linear regression model could be implemented in all techniques, albeit the R2 coefficient of determination values were higher than those for the FS-LASIK (0.599) and LASIK (0.494) techniques. There is a positive correlation between post-surgical SE value and post-operative LogMAR UDVA. These regression models can be adjusted to predict the final UDVA according to the final SE. The techniques that are most influenced by the final SE in terms of their visual results are FS-LASIK and LASIK.

Comparison between aberration-free transepithelial photorefractive keratectomy and small incision lenticule extraction for correction of myopia and myopic astigmatism.

To evaluate the clinical outcomes of small incision lenticule extraction (SMILE) and aberration-free transepithelial photorefractive keratectomy (AF t-PRK) in patients with low to moderatemyopic astigmatism, including visual acuity, refractive outcomes, astigmatic vector analysis and corneal aberrometric changes. This retrospective comparative case series study involved 110 right eyes of 110 patients who underwent either SMILE (55 eyes) or AF t-PRK (55 eyes). Visual acuity, manifest refractive error and corneal higher-order aberrations (HOAs) were measured and analyzed at baseline, 1month and 3months after operation. The safety and efficacy indices, and vector parameters were also compared. 1month postoperatively, the mean uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA) and spherical equivalent refraction (SE) were better after SMILE than AF t-PRK (logMAR UDVA, - 0.03 ± 0.07 and - 0.006 ± 0.07, P = 0.050; logMAR CDVA, - 0.06 ± 0.07 and - 0.03 ± 0.07, P = 0.043; SE, - 0.04 ± 0.25 and 0.15 ± 0.26, P < 0.001). However, these parameters were comparable between the groups at 3months after surgery. Residual astigmatism ≤ 0.25 diopters was observed in 74.5% and 90.9% (P = 0.023) of the eyes at one month and in 87.3% and 85.5% (P = 0.781) of the eyes at 3months after SMILE and AF t-PRK, respectively. There were no significant differences between the groups in any of the vector parameters at 1month or 3months after surgery. Coma and total HOAs after SMILE were significantly higher than AF t-PRK (1month coma, 0.49 ± 0.23 and 0.29 ± 0.15, P < 0.001; 1month total RMS HOAs, 0.65 ± 0.20 and 0.54 ± 0.14, P = 0.001; 3months coma, 0.50 ± 0.22 and 0.30 ± 0.17, P < 0.001; 3months total RMS HOAs, 0.68 ± 0.20 and 0.55 ± 0.17, P < 0.001). In this study, both SMILE and AF t-PRK were effective and comparable for correction of low to moderate myopic astigmatism. AF t-PRK group induced less coma and total HOAs than SMILE.

The role of preoperative Pentacam in optimizing visual outcome after cataract surgery

Objective To evaluate the role of preoperative Pentacam in optimizing visual outcome after cataract surgery. Background It has been suggested that Pentacam gives comprehensive data about preoperative astigmatism, lens density, and refractive power helping in optimizing the visual outcome after cataract surgery. Patients and methods Preoperatively, the patients were subjected to careful history taking, thorough ocular examination including assessment of manifest refraction, measurement of logMAR uncorrected distance visual acuity, and corrected distance visual acuity, biometry and keratometry with the Intraocular lens (IOL) Master partial coherence interferometry device, corneal topography (Pentacam) and to exclude irregular astigmatism, mean lens density, and cataract grading score were evaluated. Slit lamp examination, dilated funduscopy under pharmacological, intraocular pressure, and Hoffer Q formula was used in eyes with an axial length shorter than 22 mm, and SRK/T formula was used for all other cases. Cataract surgery were performed according to the standard protocols. Postoperative manifest refraction (sphere and cylinder) and visual acuity (uncorrected and corrected) were obtained. Results There was significant improvement of astigmatism postoperatively. Also, there were significant improvements of UCVA and BCVA in postoperative assessment as compared with preoperative evaluation. Conclusion Preoperative Pentacam can help in the improvement of preoperative astigmatism. It also resulted in the improvement of Uncorrected visual acuity (UCVA) and Best corrected visual acuity (BCVA).