Correction Of Myopia Research Articles

Orthokeratology for high myopia

Purpose. With an increasing proportion of children with myopia especially in Asia, efforts have been made to reduce chances of preventable sight loss related to high myopia in the future. Orthokeratology lens has been used as one of the modalities not just to correct myopia, but also to slow down myopic progression and axial elongation. This case report reviews a patient with clinically significantly high myopia, whose refractive errors was partially corrected with orthokeratology lens and spectacle lenses. Material and Methods. A now 14-year-old patient with a history of fast progressing myopia, was prescribed and commended orthokeratology to manage myopia, while regularly monitoring her refractive errors, axial length, binocular vision status, corneal topography, and anterior eye health was monitored regularly at the author’s practice. Results. Over a two year follow up period, a partial correction of high myopia with orthokeratology lenses and residual refractive errors with additional spectacle lenses was effective in managing this patient’s myopia, as well as slowing of axial elongation. An updated pair of orthokeratology lens with a steeper back optic zone radii were prescribed to reduce superficial corneal staining and to maintain corneal health. Conclusion. Patient commitment and adherence to close monitoring of eyes in terms refractive errors, axial length, and anterior eye health, are vital in achieving a successful orthokeratology lens wear for high myopia. A dual fitting strategy consisting of orthokeratology lens and spectacle wear can be a safe management strategy that is acceptable for patients with high myopia. It would be helpful for practitioners to be able to rely on robust evidence-based guidance when determining whether lens wear can be ceased, i.e. when further axial elongation and myopic progression are no longer likely.

On the issue of complications following excimer laser correction of ametropia

Background. Diffuse lamellar keratitis is a rare yet severe postoperative complication that may arise following excimer laser correction of myopia. Research indicate that the incidence of this condition after LASIK ranges from 4.3 to 18.9 %, and after FemtoLASIK, it varies from 0.5 % to more than 37.5 %. Given the increasing popularity of LASIK and FemtoLASIK technologies, studying the frequency and clinical characteristics of this complication is crucial for enhancing treatment outcomes and patient safety. This study purposed to explore the clinical course and frequency of diffuse lamellar keratitis following different excimer laser technologies used for myopia correction. Materials and methods. We conducted a prospective, cohort, non-interventional study. It involved 180 patients (360 eyes) who underwent myopia correction using either LASIK (182 eyes) or FemtoLASIK (178 eyes). Postoperative monitoring included visual acuity, refraction, and biomicroscopy to identify potential complications, particularly diffuse lamellar keratitis. We examined the frequency and clinical course of the condition after each type of excimer laser correction. The observation period is 1 year. Results. Upon examination one week after excimer laser correction, the incidence of diffuse lamellar keratitis in the first group was 4.95 %, while in the second group it was 6.74 %. One month after surgery, there was a reduction in the frequency of diffuse lamellar keratitis: in the first group, it decreased to 3.30 %, and in the second group, to 2.81 %. By the three-month follow-up, the first group showed no manifestations of diffuse lamellar keratitis, whereas the second group had an incidence of 0.56 %. At the six-month follow-up, the incidence in the first group was 0.55 %, and there were no clinical manifestations of diffuse lamellar keratitis in the second group. At the one-year follow-up, neither group exhi­bited clinical signs of this disease. The clinical course and manifestations of diffuse lamellar keratitis did not differ between LASIK and FemtoLASIK throughout the study period. Additionally, it was found that 38.46 % of the patients had a history of SARS-CoV-2 infection. Conclusions. Our research revealed that the frequency of diffuse lamellar keratitis was 6.3 % after LASIK and 6.6 % after FemtoLASIK over a 1-year period. The clinical course and manifestations of the condition were similar for both LASIK and FemtoLASIK at all observation points. In was found that 38.46 % of patients who developed diffuse lamellar keratitis after excimer laser correction had a history of SARS-CoV-2 infection (from 2 weeks to 2 months). Future research should focus on investigating new local (ocular) and systemic (whole body) pathogenetic factors of diffuse lamellar keratitis following modern excimer laser methods for ametropia correction.

One-Year Visual and Refractive Outcomes of SmartPulse® Technology in Transepithelial Photorefractive Keratectomy for Myopic and Astigmatic Patients.

Background/Objectives: This study aims to evaluate the efficacy, safety, and predictability of Transepithelial Photorefractive Keratectomy (TPRK) using the SmartPulse® technology excimer laser for the correction of myopia and myopic astigmatism, assessing visual and refractive outcomes over a one-year follow-up period. Methods: This retrospective cohort study analyzed data from patients who underwent TPRK at the Ophthalmology Department-"Victor Babes" University of Medicine and Pharmacy in Timisoara (Romania), between January 2019 and June 2023. The procedure was performed using the SmartPulse® Technology of the SmartSurfACE AMARIS 750S excimer laser (SCHWIND eye-tech-solutions, Kleinostheim, Germany). Preoperative assessments included visual acuity, refraction, and corneal measurements, with postoperative evaluations conducted for up to 12 months. Results: This study included 92 eyes from 46 patients (mean age 29.02 years, 63% male). At 12 months post-op, 100% achieved UDVA 20/25 or better, with an efficacy index of 1.01. Refractive accuracy was 96% within ±0.50 D of the target and astigmatism ≤ 0.50 D in 99% of eyes. The safety index was 1.01. Corneal haze occurred in 8.70% of eyes and was effectively managed with dexamethasone drops. Conclusions: TPRK with the SmartPulse® technology excimer laser demonstrated high efficacy and safety in correcting myopia and myopic astigmatism, achieving stable visual outcomes over one year. The procedure also showed excellent predictability with a low incidence of complications, supporting its use as a reliable refractive surgery option.

Assessing the predictability of five intraocular lens calculation methods in eyes with prior myopic keratorefractive lenticule extraction.

To evaluate and compare the predictability of five methods of intraocular lens (IOL) calculation in eyes with prior keratorefractive lenticule extraction (KLEx) for the treatment of myopia. A retrospective case study included 100 eyes of 52 patients who underwent myopia and myopia with astigmatism treatment with small incision lenticule extraction (SMILE). Preoperative and 3-month postoperative measurements of optical biometry and corneal tomography were obtained. The spherical equivalent of the refractive change induced by surgery was converted to the corneal plane (SMILE-dif). A physically well-defined method was developed in which the same IOL model was implanted before and after SMILE. IOL power was calculated using ray-tracing (RT-Sirius), and several IOL power calculation formulas (Kane, EVO 2.0, Barrett Universal II Formula, Hoffer QST) before surgery. After surgery, IOL power was calculated with RT-Sirius, Kane using Mean Pupil Power at 5.5mm by ray tracing, EVO 2.0 Post Myopic LASIK/PRK, Barrett True K and Hoffer QST Post Myopic LASIK/PRK after surgery. The difference between the refractive error induced by the IOL before and after SMILE in the corneal plane (IOL-dif) was compared with SMILE-dif. The predicted error (PE) was calculated as the difference between SMILE-dif and IOL-dif. The PE obtained was 0.26 ± 0.55 diopters (D), 0.10 ± 0.45 D, 0.40 ± 0.37 D, -0.03 ± 0.36 D, 0.02 ± 0.51 D, with RT-Sirius, Kane, EVO 2.0, Barrett True K, and Hoffer QST respectively. PE was not statistically significantly different between Barrett True K and Hoffer QST, with differences being more homogeneous with Barrett, (variance σ2 = 0,13). The absolute EP obtained with Barrett True K achieved 84% of cases within ± 0.5 D, followed by Kane (72%), Hoffer QST (65%), EVO (61%) and RT-Sirius (59%). Barrett True K formula was the most accurate method for IOL calculation in eyes that had undergone SMILE for the correction of myopia. What is known The literature regarding IOL power calculation after SMILE is sparse, and the methods used to estimate corneal power following LASIK/PRK may not be applicable to SMILE procedures. The most common approach to investigating the predictability of IOL calculation formulas involves a theoretical model encompassing the virtual implantation of an IOL. What is new The Hoffer QST formula, Kane formula using Mean Pupil Power at 5.5mm, EVO 2.0, and Sirius' Ray Tracing software had not been previously evaluated using this approach. The Barrett True K formula was the most accurate method for IOL calculation in eyes that had undergone SMILE for myopia correction, outperforming Ray Tracing.

Vat photopolymerization of multifunctional fresnel lenses for ocular management.

In this study, multifunctional Fresnel lenses were explored as a potential solution for correcting vision in patients with color vision deficiency (CVD) and high myopia. Current studies have primarily focused on color vision correction through the 3D printing of glasses and contact lenses. However, the potential of 3D-printed multifunctional devices, such as Fresnel lenses, goes beyond addressing a single vision correction issue. For this study, computer-aided design (CAD) model of Fresnel lens with high diopter based on constant height configuration was developed. The CAD model was successfully fabricated using vat photopolymerization 3D printer, employing laboratory-prepared transparent HEMA resin. The resin was modified with two Atto dyes (565nm and 488nm), known for their ability to filter out problematic wavelengths (400-500nm and 540-580nm) to address color vision deficiency. The printed lenses were characterized by their chemical, physical, and optical properties using various characterization techniques. The focusing performance was evaluated using focal length measurements, and the results obtained were less than 2mm deviation from the design value, having the potential to assist in higher myopic vision correction. The resulting optical spectra were compared with commercial glasses, revealing close agreement for CVD correction. These results expand the potential applications of multifunctional Fresnel lenses in ophthalmology, demonstrating their effectiveness as vision-correcting lenses and imaging systems.

Seven-year refractive outcomes comparing small incision lenticule extraction and femtosecond laser-assisted in situ keratomileusis for myopia and myopic astigmatism.

This study aimed to compare the seven-year refractive outcomes of small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for correction of myopia and myopic astigmatism. This retrospective cohort study included 97 eyes of 53 patients who had undergone SMILE or FS-LASIK for myopia seven years prior. Measured parameters included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and manifest refraction. There were no significant differences between the SMILE and FS-LASIK groups in logMAR UDVA, cylinder, and logMAR CDVA at 7 years postoperatively (P>0.05). However, there were significant differences between the two groups in sphere and spherical equivalent (P=0.035 and P=0.016, respectively). UDVA was better than or equal to 20/20 in 81% of the eyes after SMILE and in 63% after FS-LASIK (P = 0.045). The efficacy indices of the SMILE and FS-LASIK groups were 1.04 ± 0.23 and 0.97 ± 0.23 (P=0.405), and the safety indices were 1.18 ± 0.19 and 1.10 ± 0.17 (P=0.543), respectively. This study demonstrates the good predictivity of both SMILE and FS-LASIK. SMILE could offer superior refractive outcomes than FS-LASIK during a 7-year follow-up in correcting myopia and myopic astigmatism.

Updating the no-history method in intraocular lens power calculation after myopic laser vision correction.

To describe the Shammas-Cooke formula, an updated no-history (NH) formula for IOL calculation in eyes with prior myopic laser vision correction (M-LVC), and to compare the results with the Shammas PL, Haigis-L, and Barrett True-K NH formulas. Bascom Palmer Eye Institute (BPEI), The Lennar Foundation Medical Center, University of Miami, Miami, Florida; Dean A. McGee Eye Institute (DMEI), University of Oklahoma, Oklahoma City, Oklahoma; and private practice, Lynwood, California, and St Joseph, Michigan. Retrospective observational study. We analyzed 2 large series of cataractous eyes with prior M-LVC. The training set (BPEI series of 330 eyes) was used to derive the new corneal power conversion equation to be used in the new Shammas-Cooke formula and the testing set (165 eyes of 165 patients in the DMEI series) to compare the updated formula with 3 other M-LVC NH formulas on the ASCRS calculator: Shammas PL, Haigis-L, and Barrett True-K NH. Mean prediction error was 0.09 ± 0.56 diopters (D), -0.44 ± 0.61 D, -0.47 ± 0.59 D, and -0.18 ± 0.56 D and the mean absolute error was 0.43 D, 0.60 D, 0.61 D, and 0.45 D for the Shammas-Cooke, Shammas PL, Haigis-L, and Barrett True-K NH, respectively. The percentage of eyes within ±0.50 D was 66.7% vs 47.9%, 48.5%, and 65.5%, respectively. The Shammas-Cooke formula performed better than the Shammas PL and Haigis-L (P < .001 for both) and as well as the Barrett True-K NH formula (P = .923).

Phakic intraocular lens exchange due to severe uveitis/inflammation: case report

Introduction: Phakic intraocular lenses (IOLs) provide excellent visual and refractive outcomes with a high safety profile. This report illustrates a case of a rare episode of severe anterior segment inflammation after iris-claw foldable lens implantation, which required surgical reintervention. Patient and Clinical Findings: A 22-year-old woman was submitted to Artiflex implantation for the correction of myopia. Three months postoperatively, a severe anterior segment inflammation developed with pigment deposition, pupillary membrane formation, and decreased visual acuity in the left eye. Diagnosis, Intervention, and Outcomes: Given the nonresponse to medical treatment (topical and systemic corticosteroid for 3 months), surgical explantation of the IOL with peeling of a pigmentary membrane over the crystalline lens was performed. During a 24-month follow-up period, the patient was monitored to exclude the development of cataract or glaucoma. Afterward, an implantable collamer lens was implanted with an uneventful intraoperative and postoperative period. During the long-term follow-up, no further pigment dispersion, uveitis, or cataract was described. Conclusions: Persistent anterior uveitis with pigmentary membrane formation after iris-claw lens implantation is a rare complication. IOL explantation needs to be considered to prevent further sequelae after severe uveitis when the situation is unresponsive to medical treatment.

Ten-year evaluation on efficacy, safety and predictability of femtosecond laser corneal small incision lenticule extraction for correction of myopia and myopic astigmatism: A case series

Objective: To evaluate the 10-year long-term outcomes of patients undergoing small incision lenticule extraction (SMILE). Methods: In this continuous case series, we enrolled a total of 113 patients (208 eyes) who underwent SMILE 10 years prior. Measured parameters included uncorrected visual acuity (UCVA), corrected distance visual acuity (CDVA), cycloplegia spherical equivalent error (SER). Results: 113 patients were enrolled in this study. Patients’ age ranged from 18 to 44 years (mean: 30.2 years). 193 eyes (92.8%) and 176 eyes (84.6%) had an UCVA≥20/20 at 3 months and 10 years postoperatively. The mean efficacy index, measured at 3 months and 10 years postoperatively, were 1.041 and 1.023, respectively; the difference was not statistically significant.Three months after operation, best-corrected visual acuity (BCVA) decreased by 1 line in 19 eyes (9.1%), remained unchanged in 158 eyes (76.0%), increased by ≥1 line in 31 eyes (14.9%). Ten years after operation, BCVA decreased by 2 lines in 15 eyes (7.2%) and by 1 line in 35 eyes (16.8%); remained unchanged in 142 eyes (68.3%); increased ≥1 line in 16 eyes (7.7%). The mean safety index, measured at 3 months and 10 years postoperatively, were 1.147 and 1.331, respectively; the difference was not statistically significant. The mean SER at 3 months and 10 years postoperatively was -0.112 and -0.276, respectively; the difference was statistically significant. Conclusion: There was a decrease in SER 10 years after SMILE surgery compared with 3 months postoperatively, there was no significant decrease in the efficacy index or safety index.

Clinical Performance of an Extended Range of Vision Intraocular Lens After LASIK.

To evaluate the clinical and patient-reported outcomes (PROMs) of cataract surgery with implantation of a wavefront-shaping extended depth of focus (EDOF) intraocular lens (IOL) in eyes with previous laser in situ keratomileusis (LASIK) for myopia correction. This prospective observational study enrolled 50 eyes with previous LASIK from 25 patients (age: 46 to 70 years) who underwent cataract surgery with implantation of the AcrySof IQ Vivity IOL (Alcon Laboratories, Inc). Visual and refractive outcomes were evaluated during a 3-month follow-up. PROMs were evaluated with the Intraocular Lens Satisfaction (IOLSAT; Alcon Vision, LLC) (general satisfaction), Catquest-9SF (difficulty in doing vision-related activities), and Questionnaire for Visual Disturbances (QUVID; Alcon Vision, LLC) (photic phenomena) questionnaires. Mean 3-month postoperative binocular uncorrected distance, intermediate, and near visual acuities were 0.02 ± 0.11, -0.02 ± 0.09, and 0.14 ± 0.13 logarithm of the minimum angle of resolution (logMAR), respectively. Mean binocular distance-corrected intermediate and near visual acuities were 0.05 ± 0.11 and 0.32 ± 0.14 logMAR, respectively. All eyes had a postoperative spherical equivalent within ±0.75 diopters (D). The mean defocus curve showed visual acuity values better than 0.20 logMAR for defocus levels from +0.50 to -1.50 D. Most patients (92.0%) confirmed that they had no vision-related difficulties limiting their normal daily life. Perception of starbursts, halos, glare, hazy vision, blurry vision, and double vision was referred by 24%, 24%, 28%, 28%, 8%, and 4% of patients, respectively. Most of symptoms were described as mild and not or a little bothersome. The wavefront-shaping EDOF IOL evaluated provides efficacious distance, intermediate, and near visual restoration in eyes with previous LASIK, with minimal photic phenomena associated. [J Refract Surg. 2024;40(10):e742-e753.].

Comparative study of visual and refractive outcomes of laser assisted in situ Keratomileusis versus small incision lenticule extraction versus implantable collamer lens for moderate to high myopia correction

Background Myopia represents a condition of refraction, in which parallel light rays converge in front of the resting eye retina. Aim To compare the laser assisted in situ keratomileusis (LASIK) visual and refractive outcomes versus small incision lenticule extraction (SMILE) versus implantable collamer lens (ICL) while correcting cases having moderate to high myopia. Patients and methods Our research involved 60 eyes having moderate to severe myopia ranging from –3 to –10 dioptres. They divided into three equal groups, group A: through LASIK, group B: through SMILE, and group C: received an ICL. Preoperative uncorrected visual acuity, Corrected distance visual acuity, and Manifest and cycloplgic refraction assessments were accomplished. Results Postoperative uncorrected visual acuity exhibited no significant variation among groups A and B, yet a significant variation was documented among groups A and C as well as among groups B and C P less than 0.001. The postoperative spherical error showed no significant variation among groups A and B nor among groups B and C yet exhibited significant variation among groups A and C P=0.002. Postoperative astigmatism was no significant variation among groups A as well as B, yet a significant variation was documented among groups A and C in addition to between groups B and C. Postoperative spherical equivalent was a significant variation among groups A and C P less than 0.001 and among groups B and C P less than 0.001. Conclusion Visual outcomes were comparable between LASIK, SMILE, and ICL. The three procedures exhibited superior effectiveness, safety, stability, and accuracy in the treatment of moderate and high myopia.

Comparison of visual quality after Q value-guided FS-LASIK and SMILE for correction of myopia with age-related accommodation deficiency

Comparison of visual quality after Q value-guided FS-LASIK and SMILE for correction of myopia with age-related accommodation deficiency

Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile.

The study aims to evaluate visual acuity and objective visual quality before and after the monocular bi-aspheric ablation profile for correction of presbyopia surgery. This prospective self-control study included 20 cases and 38 eyes of patients who underwent monocular bi-aspheric ablation profile correction of myopia with presbyopia at the Eye Hospital of Shandong University of Traditional Chinese Medicine from January 2023 to January 2024. These patients were selected for observation, and each patient's preoperative and postoperative uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), spherical aberration (SA) (within 6 mm), horizontal and vertical coma (within 6 mm), and corneal aspheric index (Q-value) (within 6 mm) were evaluated. Statistical data analysis was performed at different time points before and after the operation. There were statistically significant differences in UDVA between dominant and non-dominant eyes before and after surgery (Z = -3.784, p < 0.001; Z = -3.817, p < 0.001). Post-operatively, 90% of the non-dominant eyes achieved UNVA of J1 and above, and 95% of the bilateral eyes achieved UNVA of J1 and above. Significant differences were found in the SA of the dominant eyes, which showed a positive increase (Z= -3.784, p < 0.001); however, compared with the dominant eye, the SA of the non-dominant eye was negatively increased, but the difference was not statistically significant (p = 0.08). There was a significant difference in the vertical coma of the dominant eye before and after the operation, but there was no significant difference in non-dominant eyes. There was no significant difference in the change of binocular horizontal coma before and after the operation. There were significant changes in the Q value of both eyes before and after the operation (Z = -3.923, p < 0.001; Z = -3.51, p < 0.001). After the monocular bi-aspheric ablation profile, the cornea of the non-dominant eye showed a prolate shape, negative SA increased, and the UDVA and UNVA improved after the operation.

Disseminated lamellar keratitis after excimer laser correction of myopia and myopic astigmatism: 6 months of observation

Disseminated lamellar keratitis after excimer laser correction of myopia and myopic astigmatism: 6 months of observation

Prevalence, sociodemographic risk factors, and coverage of myopia correction among adolescent students in the central region of Portugal

BackgroundKnowing the prevalence of myopia at school age is essential to implement preventive measures and appropriate interventions, ensure access to vision care, promote a healthier educational environment and improve academic performance. The purpose of this study was to determine the prevalence of myopia and its associated sociodemographic risk factors, as well as to estimate the coverage of myopia correction among adolescents in center of Portugal.MethodsThis cross-sectional study evaluated 1115 adolescents from the 5th to the 9th year of school, with an average of 12.9 years (SD = 1.5) ranging from 10.0 to 18.0 years. Optometric evaluations were carried out in a school environment and consisted of the evaluation of distance visual acuity, assessed using a logarithmic visual acuity chart (ETDRS charts 1 and 2) at 4 m, and measured by refractive error with a pediatric autorefractometer (Plusoptix), by non-cycloplegic. Myopia was defined as spherical equivalent (SE ≤ -0.50 diopter (D)) and uncorrected visual acuity (UVA ≤ 95VAR). Adjusted logistic regression analysis was applied to investigate risk factors.ResultsWe found a myopia rate of 21.5% and a high myopia rate of 1.4%. Higher school level and attendance at urban schools were associated with myopia, but no association was found with age or sex. Only 34.6% of myopic adolescents use the best optical correction and 26.4% do not use any type of optical correction.ConclusionsData on the prevalence of refractive problems in Portugal are scarce and heterogeneous. This study, although regional, provides a valuable contribution with a clear and reproducible methodology, following international guidelines and filling gaps in the existing literature. The results show that the rate of myopia in this age group is similar to reports from other European studies. The high rate of adolescents with uncorrected or under-corrected myopia in Portugal is a problem that deserves attention.

Comparison of the Effects of Orthokeratology and Highly Aspherical Lenselets in Achieving Myopia Control and Defocus in Adolescents.

To compare the control effectiveness and periretinal defocus between orthokeratology (OK) and highly aspherical lenslets (HAL) in adolescents with myopia. In this prospective study, 211 children (211 right eyes) were enrolled in Beijing Ming Vision and Ophthalmology between October 2022 and February 2023. Based on the myopia correction method, participants were divided into three groups: OK, HAL, and single-vision spectacles (SVS). They were further divided into two subgroups according to the spherical equivalent (SE), namely, subgroup A with -1.0≤SE≤-2.0 D and subgroup B with -2.0<SE≤-3.0 D. All children were followed up for 12 months, and the changes in axial length (AL) and periretinal defocus before and after treatment were recorded, and the factors affecting the corneal shaping force for 1-day post-OK were analyzed. Axial length growth in those with OK lenses and HAL was lower than what was observed for those with SVS after 6, 9, and 12 months. Comparison of the difference in AL change between OK and HAL was not statistically significant with -1.0≤SE≤-2.0 D. The myopic defocus of RDV270° to 300° in group HAL was higher than that in group OK, the difference was statistically significant ( P <0.05), and in other regions, the myopic defocus was higher in the group OK. Em, SRI (corneal regularity index), variation in cell area, and corneal thickness were significantly associated with shaping force. Orthokeratology is one of the most effective optical treatments for controlling myopia, and the factors that affect the corneal shaping force under different corneal parameters are different. For mild myopia, HAL can achieve the same effectiveness as OK.

12-Month Visual and Refractive Outcomes of Topography-guided Femtosecond Laser-Assisted LASIK for Myopia and Myopic Astigmatism.

To report 12-month visual and refractive outcomes following topography-guided femtosecond laser-assisted laser in situ keratomileusis (LASIK) for myopia and compound myopic astigmatism correction. This prospective, single-center observational study was conducted in an outpatient clinical practice at the Stanford University Byers Eye Institute in Palo Alto, California. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity, 5% and 25% contrast sensitivity CDVA, and manifest refraction following topography-guided femtosecond laser-assisted LASIK were assessed. Refractive measurements were used to perform a vector analysis. Sixty eyes of 30 patients (mean age: 32.8 ± 7.0 years; range: 23 to 52 years) undergoing topography-guided LASIK for the correction of myopia and compound myopic astigmatism were analyzed. Mean postoperative UDVA was -0.09 ± 0.10 logarithm of the minimum angle of resolution (logMAR) at 12 months. Mean preoperative CDVA was -0.09 ± 0.09 and -0.13 ± 0.08 logMAR at postoperative 12 months. At 12 months, 26.9% of eyes had gained one or more lines of postoperative UDVA compared to baseline CDVA. Mean pre-operative 5% contrast sensitivity CDVA was 0.68 ± 0.07 and 0.64 ± 0.12 logMAR at 12 months (P = .014) following LASIK. Topography-guided LASIK for myopia and myopic astigmatism correction provided excellent visual and refractive outcomes that were predictable, precise, and stable up to 12 months postoperatively. [J Refract Surg. 2024;40(9):e595-e603.].

Comparison between 80-microns versus 100-microns flap femtosecond LASIK for correction of myopia and myopic astigmatism.

This study aimed to compare the safety, efficacy, and visual outcomes of 80-microns LASIK versus 100-microns LASIK in managing myopia and myopic astigmatism. The study was conducted at a tertiary care hospital in North India. This was a prospective contralateral eye study that included patients with myopia and myopic astigmatism seeking refractive correction. The eligibility criteria included normal corneal topography, an epithelial thickness less than 60 microns, a calculated percentage tissue ablation (with 100-microns flap) less than 40%, a calculated residual stromal bed thickness (with 100-microns flap) more than 300 microns, and willingness to participate and follow up. Patients with glaucoma, cataracts, other visually disabling ocular pathologies, and a history of past ocular surgery were excluded. All patients underwent LASIK with 80-microns LASIK in one eye and 100-microns LASIK in the other eye. The patients were followed up for 6 months, and the results were analyzed. The study included 216 eyes of 108 patients. The mean preoperative spherical equivalent in the 80-microns group and the 100-microns group was -3.53 ± 1.81 and -3.69 ± 1.32 diopters, respectively (P = 0.78). The mean 6 months decimal postoperative UCVA was 0.98 ± 0.13 in the 80-microns group and 0.97 ± 0.14 in the 100-microns group (P = 0.99). The postoperative change in the higher-order aberration profile was comparable in both groups (P = 0.78). The percentage tissue ablation was significantly lower in the 80-microns group (P = 0.002). The incidence of flap micro striae and OBL was higher in the 80-microns group, while neither of these had any visual implications. The study concluded that 80-microns LASIK is an efficacious and safe alternative to 100-micron LASIK, especially useful in patients with higher myopia.

Comparative analysis of surgically induced astigmatism following cataract surgery: influence of previous myopic correction and corneal parameters.

This retrospective study investigated the impact of corneal parameters on surgically induced astigmatism (SIA) in eyes with prior myopic correction undergoing cataract surgery. Department of Ophthalmology, San Marino Hospital, San Marino, Republic of San Marino. This case-control study analyzed existing data retrospectively, without randomization or masking. Eighty eyes divided in group 1 (40 eyes previous underwent refractive surgery for myopia) and group 2 ( 40 myopic eyes) that underwent cataract surgery with intraocular lens (IOL) implantation were included. SIA was calculated using values from the IOL Master Zeiss 700 and mean pupil power (MPP) derived from the CSO Sirius Topographer (based on 3mm pupil size) with vectorial analysis from doctor Hill software. No significant difference in SIA was observed between eyes with prior myopic photorefractive keratectomy and the control group (p > 0.05). SIA calculations using the IOL Master and CSO Sirius Tomographer yielded similar results. There was no significant correlation between SIA and axial length, corneal curvature, peripheral corneal thickness, or anterior chamber depth (p > 0.05). However, an inverse correlation was found between SIA and horizontal corneal diameter (p < 0.05). Corneal parameters, such as axial length, corneal curvature, peripheral corneal thickness, and anterior chamber depth, showed no significant influence on SIA. The inverse correlation between SIA and horizontal corneal diameter in study group suggests potential influence of white-to-white distance on SIA. These findings highlight the importance of considering corneal parameters for optimizing surgical outcomes.

Comparison between a new transepithelial PRK vs. conventional alcohol-assisted PRK: Corneal densitometry and aberrometry study.

To describe and compare corneal densitometry, subjective refraction, visual acuity, and corneal higher order aberrations (HOA) after corneal refractive surgery using either alcohol-assisted photorefractive keratectomy (aaPRK) or single-step transepithelial PRK (tPRK). We conducted a retrospective and observational study. We analyzed 120 right eyes from 120 healthy consecutive myopic patients who underwent aaPRK or tPRK to correct myopia of up to 6 diopters and astigmatism of up to 2 diopters. The WaveLight EX500 excimer laser (Alcon Laboratories, Inc.) was used in all cases. Visual acuity, subjective refraction, and Pentacam AXL® measurements were performed at the preoperative visit and at 6-months follow-up visit. Pentacam AXL® software was used to assess corneal optical density in various annuli for different corneal depths and anterior corneal HOA (6 mm area of analysis). Preoperative spherical equivalent values were similar between groups preoperatively (-3.07 ± 1.52 and -3.38 ± 1.46 in the aaPRK and tPRK groups, respectively). There were no statistically significant differences in visual acuity and postoperative refraction between groups. Postoperative corneal densitometry did not show statistically significant differences in any of the areas studied and both surgical procedures obtained similar results. However, analysis of HOA showed statistically significant differences between the techniques (1.42 ± 0.39 and 1.80 ± 0.62 for the aaPRK and tPRK groups, respectively; p = 0.000). Both aaPRK and single-step tPRK gave comparable visual, refractive, and corneal density outcomes. Some differences were observed in HOA but were not clinically relevant.