Spherical Equivalent Refraction Research Articles

Effect of artificial natural light on the development of myopia among primary school-age children in China: a three-year longitudinal study.

To assess the efficacy of artificial natural light in preventing incident myopia in primary school-age children. This is a prospective, randomized control, intervention study. A total of 1840 students from 39 classes in 4 primary schools in Foshan participated in this study. The whole randomization method was adopted to include classes as a group according to 1:1 randomized control. Classrooms in the control group were illuminated by usual light, and classrooms in the intervention group were illuminated by artificial natural light. All students received uncorrected visual acuity and best-corrected visual acuity measurement, non-cycloplegic autorefraction, ocular biometric examination, slit lamp and strabismus examination. Three-year follow-up, the students underwent same procedures. Myopia was defined as spherical equivalent refraction ≤ -0.50 D and uncorrected visual acuity <20/20. There were 894 students in the control group and 946 students in the intervention group with a mean±SD age of 7.50±0.53y. The three-year cumulative incidence rate of myopia was 26.4% (207 incident cases among 784 eligible participants at baseline) in the control group and 21.2% (164 incident cases among 774 eligible participants at baseline) in the intervention group [difference of 5.2% (95%CI, 3.7% to 10.1%); P=0.035]. There was also a significant difference in the three-year change in spherical equivalent refraction for the control group (-0.81 D) compared with the intervention group [-0.63 D; difference of 0.18 D (95%CI, 0.08 to 0.28 D); P<0.001]. Elongation of axial length was significantly different between in the control group (0.77 mm) and the intervention group [0.72 mm; difference of 0.05 mm (95%CI, 0.01 to 0.09 mm); P=0.003]. Artificial natural light in the classroom of primary schools can result in reducing incidence rate of myopia during a period of three years.

Myopia Control Effect of Repeated Low-Level Red-Light Therapy Combined with Orthokeratology: A Multicenter Randomized Controlled Trial.

To investigate the efficacy and safety of repeated low-level red-light(RLRL) therapy combined with orthokeratology(Ortho-k) among the children who, despite undergoing Ortho-k treatment, exhibited an axial elongation of at least 0.50mm over 1 year. Multicenter, randomized, parallel-group, single-blind clinical trial (ClinicaTrials.gov,NCT04722874). Eligible children were aged 8-13 years with a cycloplegic spherical equivalent refraction of -1.00 to -5.00 diopters in the initial Ortho-k fitting examination and had annual axial length (AL) elongation ≥ 0.50 mm despite undergoing Ortho-k for 1 year. A total of 48 children were enrolled from March 2021 to January 2022, and the final follow-up was completed in March 2023. Children were randomly assigned to the RLRL combined with Ortho-k(RCO) or the Ortho-k group in a 2:1 ratio. The Ortho-k group wore Ortho-k at least 8 hours per night, while the RCO group received daily RLRL therapy twice a day for 3 minutes in addition to Ortho-k wearing. The primary outcome was AL change measured at 12 months relative to baseline. The primary analysis was conducted in children who received the assigned intervention and completed at least 1 post-randomization follow-up using the modified intention-to-treat principle. A total of 47(97.9%) children were included in the analysis (30 in the RCO group and 17 in the Ortho-k group). The mean axial elongation rate before the trial was 0.60mm/year in the RCO group and 0.61mm/year in the Ortho-k group. After 12 months following the intended intervention, the adjusted mean AL changes were -0.02mm(95% CI, -0.08 to +0.03 mm) in the RCO group and 0.27mm(0.19-0.34 mm) in the Ortho-k group. The adjusted mean difference in AL change was -0.29mm(-0.44 to -0.14mm) between the RCO and Ortho-k groups. The percentage of children achieving an uncorrected visual acuity greater than 20/25 was similar in the RCO (64.3%) and Ortho-k (65.5%) groups (Chi2 test, P=0.937). Combining RLRL therapy with Ortho-k may offer a promising approach to optimize axial elongation control among myopic children. This approach also potentially allows children to achieve satisfactory visual acuity, reducing the daytime dependence on corrective eyewear.

Impact of Advanced Image-Guided Systems on Correction of Corneal Astigmatism During Femtosecond Laser-Assisted Cataract Surgery

Purpose: To determine the effectiveness of the correction of corneal astigmatism utilizing the Alcon Image Guidance system (Ft. Worth, Texas) versus manual marking in the orientation of femtosecond laser-assisted astigmatic keratotomy incisions. Setting: This study was based in a private practice in Albany, New York, USA. Design: Retrospective review of patients undergoing FLACS from January 2018 to June 2022. Methods: Patients who underwent FLACS with Image Guidance (IG) and without IG were investigated. Variables including pre-operative K values, cylinder, spherical equivalent (SE), and visual acuity (VA) were collected, as well as the cyclorotation angle delta registered by IG, post- operative refractive cylinder, SE, and VA. The primary outcome was post-operative refractive cylinder in patients with IG compared to those without IG. Results: A total of 160 eyes were included, with 103 eyes who had IG and 57 eyes who did not have IG. Post-operative cylinder was similar in those with IG (0.31 +/- 0.36 D) compared to those without IG (0.31 +/- 0.37 D) (p=0.97). Average cyclorotation in the IG group was 2.82 ± 3.03 degrees. When cyclorotation was stratified into three groups (&lt;2.8 degrees, 2.8-8.5 degrees, &gt;8.5 degrees), no differences were found in post-operative refractive cylinder (p=0.35). Conclusions: Patients who underwent FLACS with Image Guidance had similar post-operative cylinder outcomes compared to those without Image Guidance. This study suggests that the accommodation of cyclotorsion using an advanced image guidance system is similar to that obtained with manual marking techniques in patients having 2 diopters or less of astigmatism corrected.

Retinal Changes From Hyperopia to Myopia: Not All Diopters Are Created Equal.

To quantitatively characterize retinal changes across different quantiles of refractive error in 34,414 normal eyes of 23,064 healthy adults in the UK Biobank. Twelve optic disc (OD), foveal and vascular parameters were derived from color fundus photographs, correcting for ocular magnification as appropriate. Quantile regression was used to test the independent associations between these parameters and spherical equivalent refraction (SER) across 34 refractive quantiles (high hyperopia to high myopia)-controlling for age, sex and corneal radius. More negative SER was nonlinearly associated with greater Euclidian (largely horizontal) OD-fovea distance, larger OD, less circular OD, more obliquely orientated OD (superior pole tilted towards the fovea), brighter fovea, lower vascular complexity, less tortuous vessels, more concave (straightened out towards the fovea) papillomacular arterial/venous arcade and wider central retinal arterioles/venules. In myopia, these parameters varied more strongly with SER as myopia increased. For example, while every standard deviation (SD) decrease in vascular complexity was associated with 0.63D (right eye: 95% confidence interval [CI], 0.58-0.68) to 0.68D (left eye: 95% CI, 0.63-0.73) higher myopia in the quantile corresponding to -0.60 D, it was associated with 1.61D (right eye: 95% CI, 1.40-1.82) to 1.70D (left eye: 95% CI, 1.56-1.84) higher myopia in the most myopic quantile. OD-fovea angle (degree of vertical separation between OD and fovea) was found to vary linearly with SER, but the magnitude was of little practical importance (less than 0.10D variation per SD change in angle in almost all refractive quantiles) compared with the changes in OD-fovea distance. Several interrelated retinal changes indicative of an increasing (nonconstant) rate of mechanical stretching are evident at the posterior pole as myopia increases. These changes also suggest that the posterior pole stretches predominantly in the temporal horizontal direction.

Safety of Repeated Low-level Red-Light Therapy for Children with Myopia

BackgroudTo investigate the safety of repetitive low-level red-light therapy (RLRLT) in children with myopia. MethodsChildren with myopia were assigned to the RLRL and control groups. Axial length (AL) and spherical equivalent refraction (SER) were followed up at 3-, 6-, and 12-month. To evaluate the safety of RLRLT, at 6 and 12 months in the RLRL group, multifocal electroretinography (mfERG) and contrast sensitivity were recorded. Furthermore, optical coherence tomography was used to measure the relative reflectance of the ellipsoid zone (rEZR), photoreceptor outer segment (rPOSR), and retinal pigment epithelium (rRPER). ResultsA total of 108 children completed the trial (55 in the RLRL group and 53 in the control group). After 3, 6, and 12 months, axial length (AL) was shorter and SER less myopic in the RLRL group than in the control group. Regarding the safety of the RLRLT, the response density and amplitude of the P1 wave of the first ring of the mfERG increased significantly at 6 months (P =0.001 and P =0.017, respectively). At 6 and 12 months, contrast sensitivity at the high spatial frequency increased. Moreover, the rEZR increased significantly at 6 months (P =0.029), the rPOSR increased significantly at 6 and 12 months (both P <0.001), and the increase in rPOSR was greater with greater AL regression. ConclusionsBased on retinal function follow-up, RLRLT was safe within 12 months. However, rEZR and rPOSR increased, the effects of this phenomenon requires further observation.

Efficacy of repeated low-level red-light therapy in the prevention and control of myopia in children

ObjectiveIn this study, we aimed to determine how different factors influence the effectiveness of repeated low-level red-light (RLRL) therapy in preventing and treating myopia in children. MethodsBetween June 2022 and April 2023, 336 children who visited our hospital due to myopia or significant decreases in hyperopia reserve were enrolled. The children were treated twice daily for three minutes with a head-mounted low-level red-light (single wavelength of 650 nm) therapeutic device. Each of the two treatment sessions was separated by at least four hours. The axial lengths and diopters of the children's eyes were compared before and three months after treatment, and the effects of gender, age, and baseline diopter on the efficacy of RLRL therapy were analyzed. ResultsFollowing three months of treatment, the average axial length of the eyes decreased by 0.031 mm. The condition was better for the boys than for girls, but the difference was not statistically significant. As age increased (F = 8.112, P = 0.000) or as the absolute value of baseline myopia degree increased (F = 10.51, P = 0.000), axial lengths of the eyes tended to decrease. The spherical equivalent refraction (SER) of children decreased by an average of 0.012 ± 0.355D. The condition was better for the boys than for girls, but the difference was not statistically significant. SER increased in the direction of hyperopic drift as age increased (F = 2.48, P=0.031), or as the absolute value of baseline myopia degrees increased (F = 6.835, P = 0.000). There were no obvious side effects following the treatment. ConclusionThis study showed that RLRL therapy is a potential efficient, easily operable, and practically feasible method for the prevention and control of myopia.

Performance of a simplified strategy for formula constant optimisation in intraocular lens power calculation.

To investigate the performance of a simple prediction scheme for the formula constants optimised for a mean refractive prediction error. Analysis based on a dataset of 888 eyes before and after cataract surgery with IOL implantation (Hoya Vivinex). IOLMaster 700 biometric data, power of the implanted lens and postoperative spherical equivalent refraction were used to calculate the optimised constants (.)opt for SRKT, HofferQ, Holladay and Haigis formula with an iterative nonlinear optimisation. For detuning start values by ±1.5 from (.)opt, the predicted formula constants (.)pred were calculated and compared with (.)opt. Formula performance metrics mean (MPE), median (MEDPE), mean absolute (MAPE), median absolute (MEDAPE), root mean squared (RMSPE) and standard deviation (SDPE) of the formula prediction error were analysed for (.)opt and (.)pred. (.)pred - (.)opt showed a 2nd order parabolic behaviour with maximal deviations up to 0.09 at the tails of detuning and a minimal deviation up to -0.01 for all formulae. The performance curves of different metrics of PE as functions of detuning variations show that the formula constants for zeroing MPE and MEDPE yield almost identical formula constants, optimisation for MAPE, MEDAPE and RMSPE yielded formula constants very close to (.)opt, and optimisation for SDPE could result in formula constants up to 0.5 off (.)opt which is unacceptable for clinical use. This simple prediction scheme for formula constant optimisation for zero mean refraction error performs excellently in our monocentric dataset, even for larger deviations of the start value from (.)opt. Further studies with multicentric data and larger sample sizes are required to investigate the performance in a clinical setting further.

Effect of 0.01% atropine combined with orthokeratology lens on axial elongation: a 2-year randomized, double-masked, placebo-controlled, cross-over trial.

To evaluate the effect of 0.01% atropine combined with orthokeratology (OK) lens on axial elongation in schoolchildren with myopia. Sixty children aged 8-12 years with spherical equivalent refraction (SER) from -1.00D to -4.00D in both eyes were enrolled in this randomized, double-masked, placebo-controlled, cross-over trial. Children who had been wearing OK lenses for 2 months were randomly assigned into combination group (combination of OK lens and 0.01% atropine) for 1 year followed by control group (combination of OK lens and placebo) for another 1 year or vice versa. This trial was registered in the Chinese Clinical Trial Registry (Number: ChiCTR2000033904, 16/06/2020). The primary outcome was changes in axial length (AL). Data of right eyes were analyzed. There were statistically significant differences in the changes in AL between combination and control groups after generalized estimating equation model adjusting for age and baseline SER (p = 0.001). The mean axial elongation difference between combination and control groups was 0.10 mm in the first year (0.10 ± 0.13 mm vs. 0.20 ±0.15 mm; p = 0.01), and 0.09 mm in the second year (0.22 ± 0.10 mm vs. 0.13 ± 0.14 mm; p = 0.01), respectively. The mean axial elongation difference of two groups in the first year was similar to that in the second year during the cross-over treatment. In central Mainland China in myopic children, the treatment of combination therapy is more effective than single OK lens in controlling axial elongation.

Does the introduction of streamlight decrease refractive surgery operating time?

The aim of the study was to analyze the time-savings associated with introduction of Streamlight™ (Alcon Laboratories, Fort Worth, TX, USA) transepithelial photorefractive keratectomy (PRK) in surface corneal ablations. All refractive surgeries were performed using the Alcon WaveLight® EX500 at the ArtLife Clinic, Gdańsk, Poland. The study included patients treated for refractive errors with transepithelial PRK between April 2019 and October 2021, who were matched with patients treated with alcohol-assisted PRK during the same period. Only results for the left eye were analyzed. One-hundred-five patients underwent transepithelial PRK (age 33.42 ± 8.67years) and were matched with 105 patients that underwent alcohol-assisted PRK (age 33.05 ± 10.16years; p = 0.11). The mean preoperative spherical equivalent refraction was - 2.04 ± 2.28 D, and - 1.9 ± 1.71 D for the transepithelial and alcohol-assisted PRK group, respectively (p = 0.20). The total surgery time was non-significantly shorter in transepithelial PRK (349.46 ± 47.83s) than in alcohol-assisted PRK (354.93 ± 137.63s; p = 0.7); however, the variance of surgical time was significantly lower in transepithelial PRK (p<0.001). The laser treatment duration was greater in transepithelial PRK (41.78 ± 17.2s) than in alcohol-assisted PRK (8.48 ± 6.12s; p < 0.001), and so was the number of breaks during the laser treatment (0.95 ± 0.63 vs. 0.53 ± 0.88, respectively; p < 0.001). The introduction of transepithelial PRK did not bring significant time-associated savings into the refractive surgery suite.

Randomised clinical trial of extended depth of focus lenses for controlling myopia progression: Outcomes from SEED LVPEI Indian Myopia Study.

To determine the efficacy of extended depth of focus (EDOF) contact lenses for controlling myopia progression in children through a 1-year randomised clinical trial. A total of 104 children aged 7-15 years, with spherical equivalent refraction ≤-0.50 D, were randomly assigned to wear SEED 1 dayPure EDOF Mid contact lenses (n=48) or single vision spectacle lenses (n=56). Cycloplegic refraction with Shin-Nippon open field autorefractor and axial length with Lenstar LS 900 was determined at the baseline and 12-month visits. The compliance, visual discomfort and dryness questionnaires were administered during the final visit. Sixty-nine children (control: n=38; treatment: 31) completed the 12-month follow-up visit, with no difference in baseline characteristics between the groups. Mean (SEM) myopia progression in the 12th month was -0.48±0.07D in the control group and -0.20±0.08D in the treatment group. Mean axial elongation was 0.22±0.03 mm and 0.11±0.03 mm in the control and treatment groups, respectively. SEED 1 dayPure EDOF Mid contact lenses slowed myopia progression by 59% (-0.28D; p=0.01) based on spherical equivalent refraction and controlled axial length by 49% (0.11 mm; p=0.007) in comparison to single vision spectacle lenses. None of the participants reported any adverse effects. While most of the participants (82%) were comfortable with the contact lenses, 11% reported occasional dryness and 14% experienced mild fluctuations in visual acuity after immediate lens wear. Daily wear of SEED 1 dayPure EDOF Mid contact lenses in Indian children showed a significant effect in controlling myopia progression and axial elongation.

Role of lens in early refractive development: evidence from a large cohort of Chinese children

AimsTo document longitudinal changes in spherical equivalent refraction (SER) and related biometric factors during early refractive development.MethodsThis was a prospective cohort study of Chinese children, starting in 2018 with annual...

Short-Term Myopic Defocus and Choroidal Thickness in Children and Adults.

Studies report conflicting findings regarding choroidal thickness changes in response to myopic defocus in humans. This study aimed to investigate the choroidal response to myopic defocus in children and adults using automated analysis. Participants (N = 46) were distance-corrected in both eyes and viewed a movie on a screen for 10 minutes. Two optical coherence tomography (OCT) radial scans were collected for each eye, then +3 diopters was added to one eye. Participants continued to watch the movie, OCT scans were repeated every 10minutes for 50minutes, and then recovery was assessed at 60 and 70minutes. Defocus was interrupted for approximately two out of each 10minutes for OCT imaging. OCT images were analyzed using an automated algorithm and trained neural network implemented in MATLAB to determine choroidal thickness at each time point. Repeated-measures ANOVA was used to assess changes with time in three age groups (6-17, 18-30, and 31-45 years) and by refractive error group (myopic and nonmyopic). Choroidal thickness was significantly associated with spherical equivalent refraction, with the myopic group having a thinner choroid than the nonmyopic group (P<0.001). With imposed myopic defocus, there were no significant changes in choroidal thickness at any time point for any age group and for either refractive error group (P>0.05 for all). Findings demonstrate that, using the described protocol, the choroidal thickness of children and adults does not significantly change in response to short-term, full-field myopic defocus, in contrast to several previously published studies.

Naked-Eye 3-Dimensional Vision Training for Myopia Control

Early onset of myopia increases the risk of high myopia, which can lead to irreversible retinal damage and even loss of central vision. To investigate the efficacy and safety of naked-eye 3-dimensional vision training (NVT) in preventing the progression of myopia in children. This randomized clinical trial was conducted in 3 hospitals from May 25, 2022, to February 24, 2023. Participants were children (aged 6-18 years) who had a diagnosis of myopia with a spherical equivalent refraction of -0.75 to -6.00 diopters (D). Children in the intervention group received 20 minutes of NVT treatment every day, whereas children in the control group lived as usual without vision training. The primary outcome was the change in axial length at 6 months. Spherical equivalent refraction (SER) was included as a secondary outcome. Among 263 participants, 125 (47.5%) were male and 138 (52.5%) were female; the mean (SD) age was 10.3 (1.9) years (range, 6.1-15.6 years). A total of 227 patients (86.3%) completed the 6-month follow-up, including 102 in the intervention group and 125 in the control group. In the intervention group, the changes in axial length and SER at 6 months were 0.18 mm (95% CI, 0.16 to 0.20 mm) and -0.25 D (95% CI, -0.31 to -0.19 D), respectively. In the control group, the changes in axial length and SER at 6 months were 0.23 mm (95% CI, 0.21 to 0.25 mm) and -0.35 D (95% CI, -0.41 to -0.30 D), respectively. The differences in AL and SER between the 2 groups were significant (AL difference: -0.06 mm; 95% CI, -0.09 to -0.03; P < .001; SER difference: 0.10 D; 95% CI, 0.02 to 0.19; P = .02). No study-related adverse reactions were reported during follow-up. NVT is a safe and promising means to control myopia progression in children with good adherence. ClinicalTrials.gov Identifier: NCT05468775.

Corneal biomechanics are not exclusively compromised in high myopia.

Research assuming linearity has concluded that corneal biomechanics are compromised in high myopia. We investigated whether this assumption was appropriate and re-examined these associations across different levels of myopia. Myopic (spherical equivalent refraction, SER ≤ -0.50 D) eyes of 10,488 adults aged 40-69 years without any history of systemic and ocular conditions were identified in the UK Biobank. Ordinary least squares (OLS) regression was employed to test the linear association between corneal hysteresis (CH) or corneal resistance factor (CRF), separately, and SER while controlling for age, sex, corneal radius and intraocular pressure. Quantile regression (QR) was used to test the same set of associations across 49 equally spaced conditional quantiles of SER. In OLS regression, each standard deviation (SD) decrease in CH and CRF was associated with 0.08 D (95% CI: 0.04-0.12; p < 0.001) and 0.10 D (95% CI: 0.04-0.15; p < 0.001) higher myopia, respectively. However, residual analysis indicated that the linearity assumption was violated. QR revealed no evidence of a significant association between CH/CRF and SER in low myopia, but a significant (p < 0.05) positive association became evident from -2.78 D (0.06 and 0.08 D higher myopia per SD decrease in CH and CRF). The magnitude of association increased exponentially with increasing myopia: in the -5.03 D quantile, every SD decrease in CH and CRF was associated with 0.17 D (95% CI: 0.08-0.25; p < 0.001) and 0.21 D (95% CI: 0.10-0.31; p < 0.001) higher myopia. In the -8.63 D quantile, this further increased to 0.54 D (95% CI: 0.33-0.76; p < 0.001) and 0.67 D (95% CI: 0.41-0.93; p < 0.001) higher myopia per SD decrease in CH and CRF. Corneal biomechanics appeared compromised from around -3.00 D. These changes were observed to be exponential with increasing myopia.

Factors associated with pathologic myopia onset and progression: A systematic review and meta-analysis.

To synthesise evidence across studies on factors associated with pathologic myopia (PM) onset and progression based on the META-analysis for Pathologic Myopia (META-PM) classification framework. Findings from six longitudinal studies (5-18 years) were narratively synthesised and meta-analysed, using odds ratio (OR) as the common measure of association. All studies adjusted for baseline myopia, age and sex at a minimum. The quality of evidence was rated using the Grades of Recommendation, Assessment, Development and Evaluation framework. Five out of six studies were conducted in Asia. There was inconclusive evidence of an independent effect (or lack thereof) of ethnicity and sex on PM onset/progression. The odds of PM onset increased with greater axial length (pooled OR: 2.03; 95% CI: 1.71-2.40; p < 0.001), older age (pooled OR: 1.07; 1.05-1.09; p < 0.001) and more negative spherical equivalent refraction, SER (OR: 0.77; 0.68-0.87; p < 0.001), all of which were supported by an acceptable level of evidence. Fundus tessellation was found to independently increase the odds of PM onset in a population-based study (OR: 3.02; 2.58-3.53; p < 0.001), although this was only supported by weak evidence. There was acceptable evidence that greater axial length (pooled OR: 1.23; 1.09-1.39; p < 0.001), more negative SER (pooled OR: 0.87; 0.83-0.92; p < 0.001) and higher education level (pooled OR: 3.17; 1.36-7.35; p < 0.01) increased the odds of PM progression. Other baseline factors found to be associated with PM progression but currently supported by weak evidence included age (pooled OR: 1.01), severity of myopic maculopathy (OR: 3.61), intraocular pressure (OR: 1.62) and hypertension (OR: 0.21). Most PM risk/prognostic factors are not supported by an adequate evidence base at present (an indication that PM remains understudied). Current factors for which an acceptable level of evidence exists (limited in number) are unmodifiable in adults and lack personalised information. More longitudinal studies focusing on uncovering modifiable factors and imaging biomarkers are warranted.

Changes in Posterior Cornea and Posterior-To-Anterior Curvature Radii Ratio 1 year After LASIK, PRK, and SMILE Treatment of Myopia.

The purpose of this study was to compare changes in the posterior curvature and the posterior-anterior radii ratio of the cornea, 1 year postoperatively in laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE). This retrospective study was performed at a single surgical center. 199 eyes were included in the study from 119 patients with manifest refraction spherical equivalents from -7.61 to -2.54 D. 67 eyes underwent LASIK, 89 underwent PRK, and 43 underwent SMILE. Both preoperative and 1-year postoperative front and back sagittal keratometry were measured at 4- to 6-mm zones around the corneal vertex. Corneal asphericity (Q-value) was measured at an 8-mm zone around the corneal vertex. The average change in the posterior-anterior radii ratio after LASIK, PRK, and SMILE did not differ between surgery groups at 4 mm (LASIK: -0.075, PRK: -0.073, SMILE: -0.072, P = 0.720), 5 mm (LASIK: -0.072, PRK: -0.068, SMILE: -0.068, P = 0.531), or 6 mm (LASIK: -0.075, PRK: -0.071, SMILE: -0.072, P = 0.456) zones. Anterior Q-value significantly positively increased after all 3 surgeries (P < 0.001). The posterior Q-value also significantly positively increased after LASIK (P < 0.001) and SMILE (P < 0.001), but not after PRK (P = 0.227). Both anterior and posterior keratometric power decreased significantly after LASIK, PRK, and SMILE for all diameters. The change in the posterior-anterior radii ratio was not influenced by the type of refractive surgery performed, as indicated by statistically identical preoperative, postoperative, and delta values. In addition, the posterior cornea exhibited paracentral flattening after LASIK, SMILE, and PRK and increased oblateness after LASIK and SMILE.

Atropine 0.01% Eye Drops for Myopia Control in a tertiary care center of Pakistan: An interventional case series

Purpose: To evaluate the real time results of once-dailyAtropine 0.01% eye drops in controlling myopia. Study Design: Interventional case series. Place and Duration of Study: The Eye Centre, South City Hospital, Karachi from September 2020 to August 2021. Methods: One hundred(both) eyes of 50 children were included in the study using non-probability consecutive sampling technique. Baseline spherical equivalent refraction(SER) was recorded at the initiation of treatment.The endpoint was measuring the rate of progression in SER at one year after treatment. Responders weredefined as the ones with either no progression of myopia or worsening of myopia of ≤ -0.50 SER and non-responders were defined as ones with a progression rate of myopia of greater than0.50 SER. Results: The baseline means SER for 100 eyes was 3.25±1.37 D. On follow-up after 12 months of treatment with Atropine 0.01% eye drops, the mean SER was -3.74 ± 1.34 D. The rate of SER progression was significantly lower at one year follow-up (p-value&lt;0.001). The percentage of responders was84%. Conclusion: Significant reduction in myopia progression occurred after treatment with Atropine 0.01% eye drops in a greater percentage of children. This has led us to be confident in providing Atropine 0.01% eye drops along with simple spectacles as an effective treatment strategy to control myopia progression.

Effectiveness of orthokeratology and myopia control spectacles in a real-world setting in China

ObjectiveTo compare the effectiveness of myopia control in Chinese children, who had been wearing either orthokeratology (ortho-k) lenses or myopia control spectacles (MCS) for one year. MethodsRelevant data were retrieved from 212 patients, with baseline myopia of −5.00 to −0.75 D, astigmatism ≤ 1.50 D, who had been undergoing myopia control treatment with either ortho-k (Euclid (OK1) or CRT (OK2)) or MCS (Stellest (MCS1) or DIMS (MCS2)) for at least one year. Myopia control effectiveness among the four groups was compared based on the change in spherical equivalent refraction (SER) (for the spectacle groups) and axial length (AL) (for all groups). Data retrieved, from the right eye only, included best corrected visual acuity (BCVA), SER, and AL at both the initial clinic visit (baseline) and the one-year visit was analysed. ResultsAlthough no significant differences in gender, cylindrical power, or BCVA were observed at the baseline visit (P > 0.05), there were significant differences in baseline age, myopia, and AL among the four groups (P < 0.05). No significant difference in axial elongation (AE) was found among the four groups after one year of treatment (P = 0.49). AE, adjusted for baseline age and spherical power, were 0.19 ± 0.15, 0.18 ± 0.14, 0.19 ± 0.19, 0.20 ± 0.18 mm for OK1, OK2, MCS1, MCS2, respectively. Only age was a significantly factor associated with AE and SER increase (P < 0.05), with negative associations between AE and age in all groups and positive association between SER increase and baseline age in the spectacle groups observed. ConclusionBoth brands of ortho-k lenses and MCS had similar myopia control effectiveness for mild to moderate myopic children treated in a real-world setting in China. Average AE in one year ranged from 0.18 to 0.20 mm, comparable to previous reports on myopia control using ortho-k.

Corneal Characteristics of Myopic Malay School Children and Their Association with Axial Length.

Corneal characteristics are unique to each eye and can vary among different levels of refractive errors. However, minimal data are available in the literature on corneal characteristics in myopic Malay school children including the difference between the low myopic group and the moderate myopic group. Therefore, this study aims to determine the corneal characteristics of myopic Malay school children and their associations with axial length. A total of eighty-four data samples were extracted from forty-two myopic Malay school children. Measurements of the central corneal thickness (CCT), corneal curvature, corneal diameter, and axial length were measured using Lenstar LS900, a non-contact optical biometer. Data were later stratified by the spherical equivalent refraction (SER) into a low myopic group and a moderate myopic group, and paired t-test were employed to determine the differences in the corneal characteristics between these two groups. Univariate and multivariate linear regressions were performed to identify factors that are significantly associated with axial length. There was no significant difference in the CCT, corneal curvature and corneal diameter between the low myopic group and the moderate myopic group (t82=0.015, P=0.99), (t82=-0.802, P=0.43) and (t82=-0.575, P=0.57), respectively. Pearson univariate correlation analysis found that axial length significantly correlated with corneal curvature (r=-0.765, P<0.001) and corneal diameter (r=0.614, P<0.001) but no significant correlation found with CCT (r=0.046, P=0.68). Multiple regression analysis showed that axial length was significantly associated with a flatter corneal curvature (P<0.001), older age (P<0.001) and larger corneal diameter (P=0.02). This study reported the corneal characteristics in myopic Malay school children and its associations with axial length. Results of this study can serve as a reference value for the myopic Malay schoolchild population.

Surgical outcomes of intraocular lens iris suture fixation in eyes with residual capsule support

Purpose: To evaluate the safety and refractive outcomes of eyes after intraocular lens (IOL) iris suture fixation (ISF). Setting: Private practice, Los Angeles, California. Design: Nonrandomized and unmasked retrospective chart review. Methods: Eyes that underwent IOL exchange or repositioning with ISF with at least 270 degrees of capsular support were included. Eyes with less than 270 degrees of capsular support and eyes with iris damage were excluded. The primary outcome measures included incidence of cystoid macular edema (CME), IOL dislocation requiring refixation, and chronic inflammation. Secondary outcome measures included worsening intraocular pressure (IOP) control, retinal tear or detachment, worsening of corrected distance visual acuity (CDVA), and corneal decompensation. Refractive outcomes for 26 subgrouped eyes included mean and median spherical equivalent refraction accuracy (SERA), and percentage of eyes within 0.5 diopter (D) and 1 D of the refractive target. Results: The study included 53 eyes of 50 patients. CME: 2/53 (3.8%), IOL dislocation requiring refixation: 2/53 (3.8%), chronic inflammation: 1/53 (1.9%), worsening IOP control: 5/53 (9.4%), retinal tear or detachment: 2/53 (3.8%). No patient experienced worsening of CDVA from baseline or corneal decompensation. Mean SERA ± SD −0.35 ± 0.29 D, median SERA −0.37 D. Of the 26 eyes subgrouped for refractive analysis, 73% were within 0.5 D and 100% were within 1 D of the desired refractive outcome. Conclusions: ISF can offer stability for sulcus-fixated IOLs provided there is some residual capsule support. Although there are measurable complications, there is a relatively low side effect profile. The refractive error tended to be myopic, indicating the need for further refinement of IOL power predictive formulas.