Surgical options and clinical outcomes for high myopia.

PURPOSE OF REVIEW: Higher degrees of myopia are currently being treated with refractive surgery. However, there is limited characterization and outcomes data for this cohort. This article aims to review the literature on highly myopic patients who had refractive surgery and present a retrospective analysis of 149 patients (270 eyes) with high to extreme myopia (≤-5.0D SE) who underwent refractive surgery [laser-assisted subepithelial keratomileusis (LASIK), photorefractive keratectomy (PRK), or implantable collamer lense (ICL)] at a single practice. RECENT FINDINGS: There is substantial literature on the efficacy of LASIK, PRK, and phakic intraocular lenses for refractive error correction, but a dearth of studies on patients with high to extreme myopia undergoing different types of refractive surgery. Our study reveals that this cohort of patients has excellent outcomes with minimal complications. SUMMARY: Our study reveals that the average preoperative myopia was highest in ICL patients (-10.03D), followed by PRK (-7.21D), and LASIK (-7.04D) patients. Not surprisingly, eyes with high myopia and thin corneas were offered and elected ICLs for their procedure. Highly myopic patients achieved outcomes consistent with data reported in the literature- average postoperative uncorrected visual acuity was 20/20 for LASIK and ICL eyes and 20/25 for PRK eyes.

Femtosecond laser-assisted in situ keratomileusis versus small-incision lenticule extraction: current approach based on evidence.

PURPOSE OF REVIEW: Laser keratorefractive surgery achieves excellent visual outcomes for refractive error correction. With femtosecond laser, small incision lenticule extraction (SMILE) is an increasingly viable alternative to laser-assisted in situ keratomileusis (LASIK). Comparative studies demonstrate similar efficacy and predictability between SMILE and LASIK, making it difficult for clinicians to choose which to use. This review thus compares femtosecond-LASIK (FS-LASK) and SMILE in various scenarios, to assist clinicians in deciding which refractive surgery procedure to recommend. RECENT FINDINGS: SMILE may be superior for highly myopic eyes due to a smaller decrease in functional optical zone. SMILE further induces less spherical aberration and less overall higher order aberrations in mesopic conditions. SMIILE also has less postoperative dry eye, making it suitable those with preexisting dry eye. For low to moderate myopic astigmatism correction, FS-LASIK has less undercorrection compared to SMILE. Lastly, SMILE has not yet received Food and Drug Administration or Conformité Européenne approval for hyperopic correction, rendering FS-LASIK the choice of procedure for hyperopic correction. SUMMARY: Both FS-LASIK and SMILE demonstrate good efficacy and predictability. Understanding specific clinical scenarios where one may be superior to the other will aid clinicians in choosing the most suitable procedure for personalized care.

Effect of spectacle correction on hyperopic children.

Background: Hyperopia is a significant refractive error in children, often leading to vision impairment. This study aimed to investigate whether partial or full spectacle correction is benefit for hyperopia in preschool-aged children. Methods: A retrospective study was conducted on hyperopic children visited to teaching medical center outpatient clinic between October 2011 and October 2018, and were categorized into three groups: full correction, overcorrection, and undercorrection. The study was approved by the institutional ethical committee of Tri-Service General Hospital. Results: Following a minimum of one-year follow-up period, no statistically significant differences were observed in best-corrected visual acuity (BCVA) among children receiving full, over, or under spectacle correction. Notably, the overcorrection group exhibited a significant reduction in spherical equivalent (SE) compared to both the full and under correction groups, indicating a better SE with spectacle overcorrection. Conclusions: Spectacle overcorrection may offer potential benefits for enhancing SE in preschool children with hyperopia. Nevertheless, further investigation through randomized controlled trials is warranted to establish the validity of this approach and its impact on visual outcomes in this hyperopic pediatric population.

Comparison of myopic control between orthokeratology contact lenses and defocus incorporated multiple segments spectacle lenses.

Purpose: The purpose of this study was to compare the differences in myopic control effects between orthokeratology (OK) contact lenses and defocus incorporated multiple segments (DIMS) spectacle lenses. Methods: A retrospective cohort study was conducted that included patients who had received OK lens, DIMS spectacle lens or single-vision spectacle treatments. A total of 54 eyes from 27 individuals, 38 eyes from 19 individuals and 42 eyes from 21 individuals were enrolled into the OK lens, DIMS and control groups, respectively. The primary outcomes were the changes in the spherical equivalent refraction (SER) and axial length (AXL) among the groups. A repeated-measure ANCOVA was adopted to calculate the SER progression and AXL elongation of the OK lens group compared with the DIMS group. Results: The difference in the SER progression was clinically non-significant in the OK lens group compared with the DIMS and control groups (P = 0.001). The total AXL elongation results were similar between the OK lens and DIMS groups, but these were lower than in the control group (P = 0.005). The repeated-measure ANCOVA revealed that the SER progression difference during the study interval was clinically non-significant in the OK lens group when compared with the DIMS group (P = 0.028). The AXL elongation results between the OK lens and DIMS populations did not illustrate a significant difference (P = 0.607). In a subgroup analysis of moderate astigmatism, better AXL control was observed in the DIMS subgroup compared with the OK lens subgroup (P = 0.016). Conclusions: The OK lens demonstrated a clinically non-significant effect on the SER and AXL controls compared with the DIMS spectacle lens.

Accuracy of intraocular lens power formulas in eyes with keratoconus: Multi-center study in Japan.

PURPOSE: To assess the accuracy of intraocular lens (IOL) power formulas, namely, SRK/T, Haigis, Barrett Universal II, Barrett True-K for keratoconus, Kane formula, and Kane formula for keratoconus, for cataract with keratoconus in Japanese eyes. SETTING: Five surgical sites in Japan. DESIGN: A retrospective case series. METHODS: Eyes with keratoconus undergoing cataract surgery were included. Postoperative refraction was compared with the prediction by the formulas. Visual acuity, manifest spherical equivalent, prediction error (PE), and mean absolute errors (MAEs) were determined 1 month postoperatively. The PE within 0.50 diopter (D), 1.00 D, and 2.00 D were compared between IOL formulas. Subgroup analysis based on the steepest keratometry (stage 1, ≤ 48 D; stage 2, > 48 D and ≤ 53 D; and stage 3, > 53 D) was performed. The relationship between PE and preoperative biometric data were assessed. RESULTS: Fifty eyes were included. The MAE of the Barrett True-K for keratoconus, Kane keratoconus, and Kane formulas were significantly lower than that of Haigis. A statistically significant difference in the prediction accuracy within ± 0.50 D was found between Kane keratoconus and Haigis. The prediction accuracy of the Barrett True-K for keratoconus, SRK/T, and Kane within ± 1.00 D was statistically significant compared with that of Haigis. In stage 3, the Barrett True-K for keratoconus had a significantly lower MAE than SRK/T and Haigis. CONCLUSION: Keratoconus-specific formulas were more accurate than existing formulas in Japanese eyes. The Barrett True-K formula for keratoconus had higher prediction accuracy in severe keratoconus.

Bi-Gaussian analysis reveals distinct education-related alterations in spherical equivalent and axial length-results from the Gutenberg Health Study.

PURPOSE: The aim of this study is to investigate the distribution of spherical equivalent and axial length in the general population and to analyze the influence of education on spherical equivalent with a focus on ocular biometric parameters. METHODS: The Gutenberg Health Study is a population-based cohort study in Mainz, Germany. Participants underwent comprehensive ophthalmologic examinations as part of the 5-year follow-up examination in 2012-2017 including genotyping. The spherical equivalent and axial length distributions were modeled with gaussian mixture models. Regression analysis (on person-individual level) was performed to analyze associations between biometric parameters and educational factors. Mendelian randomization analysis explored the causal effect between spherical equivalent, axial length, and education. Additionally, effect mediation analysis examined the link between spherical equivalent and education. RESULTS: A total of 8532 study participants were included (median age: 57 years, 49% female). The distribution of spherical equivalent and axial length follows a bi-Gaussian function, partially explained by the length of education (i.e., < 11 years education vs. 11-20 years). Mendelian randomization indicated an effect of education on refractive error using a genetic risk score of education as an instrument variable (- 0.35 diopters per SD increase in the instrument, 95% CI, - 0.64-0.05, p = 0.02) and an effect of education on axial length (0.63 mm per SD increase in the instrument, 95% CI, 0.22-1.04, p = 0.003). Spherical equivalent, axial length and anterior chamber depth were associated with length of education in regression analyses. Mediation analysis revealed that the association between spherical equivalent and education is mainly driven (70%) by alteration in axial length. CONCLUSIONS: The distribution of axial length and spherical equivalent is represented by subgroups of the population (bi-Gaussian). This distribution can be partially explained by length of education. The impact of education on spherical equivalent is mainly driven by alteration in axial length.

Effect of Posterior Keratometry on the Accuracy of 10 Intraocular Lens Calculation Formulas: Standard Keratometry versus Total Keratometry.

PURPOSE: To investigate the effect of posterior keratometry (PK) on the accuracy of 10 intraocular lens (IOL) power calculation formulas using standard keratometry (K) and total keratometry (TK). METHODS: This is a retrospective consecutive case-series study. The IOL power was calculated using K and TK measured by IOLMaster 700 in 6 new-generation formulas (Barrett Universal II, Emmetropia Verifying Optical (EVO) 2.0, RBF Calculator 3.0, Hoffer QST, Kane, and Ladas Super Formula) and 4 traditional formulas (Haigis, Hoffer Q, Holladay 1, and SRK/T). The arithmetic prediction error (PE) and mean absolute PE (MAE) were evaluated. The locally-weighted scatterplot smoothing was performed to assess the relationship between PE and PK. RESULTS: A total of 576 patients (576 eyes) who underwent cataract surgery were included. Compared with using K, all formulas using TK showed a hyperopic shift in the whole group. Specifically, for eyes with PK exceeding -5.90 D, all formulas using TK exhibited a hyperopic shift (all P < 0.001), while eyes with PK less than -5.90 D showed a myopic shift (all P < 0.001). The MAE of new-generation formulas calculated with TK and K showed no statistical differences, while the MAE of traditional formulas with TK was larger (TK: 0.34 ~ 0.43 D; K: 0.33 ~ 0.42 D, all P < 0.05). CONCLUSIONS: The prediction bias of formulas with TK increased as PK deviated from -5.90 D. TK did not improve the prediction accuracy of new-generation formulas, and even performed worse in traditional formulas.

Comparatively analysing the postoperative optical performance of different intraocular lenses: a prospective observational study.

BACKGROUND: Postoperative performance, including best corrected distance visual acuity (BCDVA) and optical metrics (from the OQAS and iTrace devices), was compared among 4 different intraocular lenses (IOLs). METHODS: This prospective observational study included 104 eyes from 104 subjects who underwent cataract surgery combined with implantation of 4 different IOLs: monofocal (Mon) IOLs, segmental refractive (SegRef) IOLs, diffractive (Dif) IOLs and extended depth of focus (EDoF) IOLs. Postoperative BCDVA and optical metrics were collected at the 6th month. The OQAS optical metrics included the objective scattering index (OSI), Strehl ratio (SR), modulation transfer function (MTF) cut-off frequency, and predicted visual acuity (PVA); the iTrace optical metrics included blur/double vision, glare/halo, starburst, mixed focus, night myopia, and night hyperopia. RESULTS: There was no significant difference in BCDVA among the 4 groups (P = 0.059; power = 70.3%). Differences were observed in all OQAS optical metrics among the groups (all P < 0.001). Overall, Mon IOLs and EDoF IOLs exhibited better performance than Dif IOLs and SegRef IOLs. Starburst was the only iTrace optical metric that differed among the groups (P < 0.001): SegRef IOLs caused more starbursts than Mon IOLs (P = 0.001), Dif IOLs (P = 0.006) and EDoF IOLs (P < 0.001). Spearman rank correlation analysis was used to determine the relationships among the iTrace optical metrics, OQAS optical metrics and BCDVA: starburst was negatively correlated with BCDVA, PVA at contrasts of 100% and 20%, OSI, and MTF cut-off frequency (all P ≤ 0.001); mixed focus was positively correlated with BCDVA, PVA at contrasts of 100% and 20%, OSI, and MTF cut-off frequency (all P ≤ 0.001). CONCLUSIONS: Postoperative BCDVA and optical metrics varied among the different IOLs, which should be taken into account in the selection and management of IOLs for cataract patients. TRIAL REGISTRATION: This study was approved by the First Affiliated Hospital of Guangzhou Medical University Ethical Review Board (No. 50 2022).

Characteristics of peripheral refractive errors in eyes of patients with non-amblyopic myopic anisometropia.

BACKGROUND: This study aims to investigate relative peripheral refractive (RPR) characteristics in children with non-amblyopic myopic anisometropia and explore potential associations between relative peripheral refractive errors (RPRE) and myopia. METHODS: Relative peripheral refractive errors were assessed in 64 children diagnosed with non-amblyopic myopic anisometropia utilizing multispectral refraction topography (MRT). Two eyes of each patient were divided into into the more myopia eyes group (ME) and the fellow eyes group (FE). Evaluated parameters encompassed total defocus values (TRDV), defocus values at eccentricities spanning 0 to 15 degrees (RDV-15), 0 to 30 degrees (RDV-30), 0 to 45 degrees (RDV-45), as well as superior (RDV-S), inferior (RDV-I), temporal (RDV-T), and nasal (RDV-N) positions. RESULTS: The study revealed a noteworthy contrast in TRDV values between Group ME (0.52 ± 0.36) and Group FE (0.17 ± 0.41), with a substantial significance (P < 0.0001). While no significant RDV-15 difference emerged between Group ME (0.01 ± 0.05) and Group FE (-0.01 ± 0.07) (P > 0.05), a meaningful RDV-30 difference existed between Group ME (0.11 ± 0.14) and Group FE (0.03 ± 0.19) (P = 0.0017). A significant discrepancy in RDV-45 was also observed between Group ME (0.39 ± 0.29) and Group FE (0.13 ± 0.34) (P < 0.001). Notably, RDV-I and RDV-T positions demonstrated marked differences between Group ME and Group FE (P < 0.0001), whereas no significant disparity was noted in RDV-S and RDV-N positions (P > 0.05). CONCLUSION: Eyes exhibiting greater myopia manifested more hyperopic peripheral defocus in the context of anisometropia. MRT as a novel ophthalmic evaluation technique, holds promising potential for broader clinical applications in the future.

A retrospective study of cumulative absolute reduction in axial length after photobiomodulation therapy.

BACKGROUND: To assess the age and timeline distribution of ocular axial length shortening among myopic children treated with photobiomodulation therapy in the real world situations. METHODS: Retrospective study of photobiomodulation therapy in Chinese children aged 4 to 13 years old where axial length measurements were recorded and assessed to determine effectiveness at two age groups (4 ∼ 8 years old group and 9 ∼ 13 years old group). Data was collected from myopic children who received photobiomodulation therapy for 6 ∼ 12 months. Effectiveness of myopia control was defined as any follow-up axial length ≤ baseline axial length, confirming a reduction in axial length. Independent t-test was used to compare the effectiveness of the younger group and the older group with SPSS 22.0. RESULTS: 342 myopic children were included with mean age 8.64 ± 2.20 years and baseline mean axial length of 24.41 ± 1.17 mm. There were 85.40%, 46.30%, 71.20% and 58.30% children with axial length shortening recorded at follow-up for 1 month, 3 months, 6 months and 12 months, respectively. With respect to the axial length shortened eyes, the mean axial length difference (standard deviation) was - 0.039 (0.11) mm, -0.032 (0.11) mm, -0.037 (0.12) mm, -0.028 (0.57) mm at 1, 3, 6, and 12-month follow-up, respectively. Greater AL shortening was observed among the older group who had longer baseline axial lengths than the younger group (P < 0.001). CONCLUSIONS: Overall myopia control effectiveness using photobiomodulation therapy was shown to be age and time related, with the maximum absolute reduction in axial elongation being cumulative.

Clinical results with a multifocal intraocular lens with a novel optical design.

BACKGROUND: To evaluate the optical performance and safety of a new multifocal lens with a novel optical design featuring two additional foci (or intensifiers) in patients with cataract and presbyopia. METHODS: In this single-center, non-randomized prospective observational study, 31 patients underwent implantation of the new multifocal IOL between March 2020 and November 2021 at a tertiary clinical center in Buenos Aires and Ramos Mejia, Argentina. Postoperative examinations with emphasis on uncorrected and corrected visual acuity at distance and near and at two different intermediate distances (80 cm and 60 cm) were performed during the 3 postoperative months. RESULTS: Of the 31 patients who underwent implantation of the new IOL, 30 underwent bilateral surgery (61 eyes in total). At 3 months, all 61 eyes had an uncorrected distance visual acuity (UCDVA) of at least 0.15 logMAR; 57 eyes (93%) had an uncorrected distance visual acuity (UCDVA) of 0.1 logMAR and 27 eyes (44%) had an UCDVA of 0.0 logMAR. At 80 cm, 60 eyes (98%) had an uncorrected intermediate visual acuity (UCIVA) of at least 0.1 log MAR and 48 eyes (79%) had an UCIVA of 0.0 logMAR. CONCLUSION: The new multifocal IOL with a novel optical concept (5 foci) showed a wide range of visual acuity especially at intermediate and near distances in patients undergoing cataract surgery. Uncorrected visual acuity was excellent at all tested distances, monocularly and binocularly, spectacle independence and patient satisfaction were high.

Analysis of surgically induced astigmatism of the anterior, posterior, and total cornea after implantable collamer lens implantation: a comparative study between temporal and superior clear corneal incisions.

BACKGROUND: To comparatively analyze the surgically induced astigmatism (SIA) of the anterior, posterior, and total corneas of eyes undertaking implantable collamer lens (ICL) implantation with temporal or superior corneal incisions. METHODS: One hundred and nine eyes of 109 patients who received ICL implantation were recruited: 40 eyes had temporal incisions and 69 eyes had superior incisions. Total corneal refractive power (TCRP); simulated keratometry of the anterior (Sim-KAnt) and posterior (Sim-KPost) corneal curvature; and astigmatism of the anterior (CAAnt), posterior (CAPost), and total (CATCRP) cornea were recorded through a Pentacam preoperatively and 3 months postoperatively. The SIA of the anterior, posterior, and total cornea were also compared between the two groups. RESULTS: There were no significant intergroup differences for TCRP, Sim-KAnt, Sim-KPost, CAAnt, CAPost, or CATCRP, preoperatively. However, values of CAAnt, CAPost, and CATCRP with temporal incision were significantly higher than those parameters with superior incision postoperatively. All of the SIA of the anterior, posterior, and total cornea were significantly lower for temporal incision than those with a superior incision (p < 0.001, p = 0.006 and p = 0.001 respectively). Meanwhile, the superior incisions created against-the-rule (ATR) astigmatism, and temporal incisions always induce with-the-rule (WTR) astigmatism in total cornea. CONCLUSIONS: A superior incision may be suitable for correcting WTR astigmatism, while a temporal incision for correcting ATR astigmatism when using a non-toric ICL. Meanwhile, temporal incision could be a better choice with little preoperative astigmatism or that preoperative astigmatism would be corrected with toric ICLs. TRIAL REGISTRATION: Registration number: ChiCTR2100051739. Prospectively registered: 01 October 2021.

Comparison of short-term clinical outcomes of a diffractive trifocal intraocular lens with phacoemulsification and femtosecond laser assisted cataract surgery.

PURPOSE: To evaluate short-term visual and refractive outcomes after implantation of a diffractive trifocal intraocular lens (IOL) in cataract patients with phacoemulsification (PHACO) and femtosecond laser assisted cataract surgery (FLACS). SETTING: Department of Ophthalmology, Shanghai Aier Eye Hospital, China. DESIGN: A retrospective, observational study. METHODS: Patients who underwent cataract surgery combined with Acrysoft IQ PanOptix trifocal IOL implantation were enrolled and divided into three groups: PHACO group, LAstig-FLACS group (astigmatism less then 1D) and HAstig-FLACS group (astigmatism more than 1D). Logarithm of the minimum angle of resolution (logMAR) visual acuity of uncorrected distance (UDVA), intermediate (UIVA), near visual (UNVA), defocus curve, surgically induced astigmatism (SIA) were evaluated in 1 months postoperatively and wavefront aberrations were evaluated in 6 months. RESULTS: 101 eyes of 60 patients were included with 31 eyes in PHACO group, 45 eyes in LAstig-FLACS group and 25 eyes in HAstig-FLACS group. Significant difference was found of internal Strehl Ratio (SR) between PHACO and LAstig-FLACS group (P = 0.026). In PHACO group, 79.31%, 86.21%, 72.41% of eyes gain visual acuity LogMAR 0.1 or more in UDVA, UIVA and UNVA, while 83.72%, 93.02%, 93.02% of those in LAstig-FLACS group and 92.00%, 84.00%, 76.00% in HAstig-FLACS group. CONCLUSIONS: Panoptix diffractive trifocal IOL provides satisfied visual outcome in no matter FLACS or PHACO. Besides, trifocal IOL implantation via FLACS can provide a better accumulative visual acuity outcome at all distance than PHACO in 1 month. Femtosecond laser assisted limbal relaxing incisions (FLLRIs) is an excellent way to reduce a patient's corneal astigmatism.

Extended depth of focus IOL in eyes with different axial myopia and targeted refraction.

AIM: To evaluate the objective visual outcomes following implantation of extended depth of focus intraocular lens (EDOF IOL) in individuals with varying axial lengths (AL) and targeted refraction. METHODS: This retrospective study comprised age-matched eyes that underwent implantation of the EDOF IOL. Eyes were categorized based on AL into groups: control group with AL < 26 mm; high myopia group with AL ≥ 26 mm. Each group was then subdivided based on postoperative spherical equivalent (SE). Follow-up at three months included assessment of uncorrected visual acuity at different distances, contrast sensitivity (CS), refractive outcomes, and spectacle independence. RESULTS: Overall, this study included 100 eyes from 100 patients, comprising 50 males (50.00%) and 50 females (50.00%), with 20 eyes in each group. In the control group, the uncorrected distance visual acuity (UDVA) at 5 and 3 m (m) in the - 1.50 to -0.75 group was inferior to that of the - 0.75 to 0.00 group (P = 0.004). Conversely, the uncorrected near visual acuity (UNVA) at 33 cm in the - 1.50 to -0.75 group was superior to that of the - 0.75 to 0.00 group (P = 0.005). Within the high myopia group, the UDVA at 5 and 3 m in the - 2.25 to -1.50 group was worse than in the - 0.75 to 0.00 group (P = 0.009 and 0.008, respectively). However, the UNVA at 33 cm in the - 2.25 to -1.50 group was better than in the - 0.75 to 0.00 group (P = 0.020). No significant differences were observed among the groups for corrected distance visual acuity (CDVA) (P > 0.05). Additionally, in the high myopia group, the CS of the - 2.25 to -1.50 group was lower compared to that of the - 0.75 to 0.00 group (P = 0.017). Among high myopia patients, 90.00% with refraction ranging from - 1.50 to -0.75 reported achieving overall spectacle independence. CONCLUSIONS: Implantation of extended depth of focus intraocular lenses (IOLs) yields satisfactory visual and refractive outcomes in eyes with axial myopia. Among high myopia patients, a refraction ranging from - 1.50 to -0.75 diopters achieves superior visual quality compared to other postoperative myopic diopters.

Prescribing patterns for hyperopia: an insight of the optometrist perspective and practice.

BACKGROUND: To investigate the current prescribing patterns for correcting hyperopia among optometrists in clinical practice in Saudi Arabia and compare those to current international guidelines. And explore the factors that influence practitioners' prescribing decision. METHOD: This cross-sectional study employed 30 items online survey that encompass demographic data, current practice and cycloplegia use, numerical response to indicate the minimum level of hyperopia at which optometrists would consider prescribing spectacles to non-strabismic children and determine the diopter value required for prescribing correction for hyperopia if present with other factors. RESULT: A total of 104 optometrists responded to the survey (52 females and 52 males). They recruited from 35 cities across Saudi Arabia. Out of total, 44% of them considered cycloplegic refraction essential under 12 years and 56% of them extended the range to 18 years. Large variation were found between the optometrists' responses and current guideline recommendations. Several factors influenced the decision-making of the practicing optometrist including signs and symptoms, bilateral hyperopia, average dioptric value, reading difficulty, and accommodative function. CONCLUSION: There are some matches between the international guidelines and the practice patterns that followed by optometrists in Saudi Arabia, however, the optometrists did not report that they are following them purposefully. These findings highlight the need to improve optometrists' practice about spectacle prescription in pediatric population.

Impact of ophthalmic clinical service use in mitigating myopia onset and progression in preschool children: a retrospective cohort study.

BACKGROUND: Although school screenings identify children with vision problems and issue referrals for medical treatment at an ophthalmic hospital, the effectiveness of this approach remains unverified. OBJECTIVE: To investigate the impact of ophthalmic clinical services on the onset and progression of myopia in preschool children identified with vision impairment. METHODS: Using data from the Shanghai Child and Adolescent Large-scale Eye Study (SCALE), this retrospective cohort study evaluated the visual development of children from three districts-Jing'an, Minhang, and Pudong-which are representative of geographic diversity and economic disparity in Shanghai's 17 districts. Initially, in 2015, the study encompassed 14,572 children aged 4-6 years, of whom 5,917 needed a referral. Our cohort consisted of 5,511 children who had two or more vision screenings and complete personal information over the follow-up period from January 2015 to December 2020. We divided these children into two groups based on their initial spherical equivalent (SE): a High-risk group (SE > -0.5 D) and a Myopia group (SE ≤ -0.5 D). Within each of these groups, we further categorized children into Never, Tardily, and Timely groups based on their referral compliance to compare the differences in the occurrence and progression of myopia. Cox proportional models were applied to estimate hazard ratios (HRs) for myopia incidence per person-years of follow-up in High-risk group. Generalized additive models(GAM) was used to calculating the progression for annual spherical equivalent changes in all children. RESULTS: Of the 5,511 preschool children (mean age, 5.25 years; 52.24% male) who received a referral recommendation, 1,327 (24.08%) sought clinical services at an ophthalmic hospital. After six years of follow-up, 65.53% of children developed myopia. The six-year cumulative incidence of myopia in the Never, Tardily, and Timely groups was 64.76%, 69.31%, and 57.14%, respectively. These percentages corresponded to hazard ratios (HRs) of 1.31 (95% CI, 1.10-1.55) for the Tardily group and 0.55 (95% CI, 0.33-0.93) for the Timely group, compared with the Never group. The HRs were adjusted for age, sex, and SE at study entry. Interestingly, the Timely group showed significantly less SE progression than the other groups (P < 0.001), and SE progression was higher in the High-risk group (-0.33 ± 0.37D/year) than in children with myopia (-0.08 ± 0.55D/year). CONCLUSION: Timely utilization of ophthalmic clinical services among children aged 4 to 6 years who fail school vision screenings can significantly reduce the incidence of myopia and slow SE progression.

Anterior chamber and angle characteristics in Chinese children (6-11 years old) with different refractive status using swept-source optical coherence tomography.

BACKGROUND: The anatomic structure of the anterior chamber (AC) helps to explain differences in refractive status in school-aged children and is closely associated with primary angle closure (PAC). The aim of this study was to quantify and analyze the anterior chamber and angle (ACA) characteristics in Chinese children with different refractive status by swept-source optical coherence tomography (SS-OCT). METHODS: In a cross-sectional observational study, 383 children from two primary schools in Shandong Province, China, underwent a complete ophthalmic examination. First, the anterior chamber depth (ACD), anterior chamber width (ACW), angle-opening distance (AOD), and trabecular-iris space area (TISA) were evaluated automatically using a CASIA2 imaging device. AOD and TISA were measured at 500, 750 µm nasal (N1 and N2, respectively), and temporal (T1 and T2, respectively) to the scleral spur (SS). Cycloplegic refraction and axial length (AL) were then measured. According to spherical equivalent refraction (SER), the children were assigned to hyperopic (SER > 0.50D), emmetropic (-0.50D < SER ≤ 0.50D), and myopic groups (SER ≤ -0.50D). RESULTS: Out of the 383 children, 349 healthy children (160 girls) with a mean age of 8.23 ± 1.06 years (range: 6-11 years) were included. The mean SER and AL were - 0.10 ± 1.57D and 23.44 ± 0.95 mm, respectively. The mean ACD and ACW were 3.17 ± 0.24 mm and 11.69 ± 0.43 mm. The mean AOD were 0.72 ± 0.25, 0.63 ± 0.22 mm at N1, T1, and 0.98 ± 0.30, 0.84 ± 0.27 mm at N2, T2. The mean TISA were 0.24 ± 0.09, 0.22 ± 0.09mm2 at N1, T1, and 0.46 ± 0.16, 0.40 ± 0.14mm2 at N2, T2. The myopic group had the deepest AC and the widest angle. Compared with boys, girls had shorter AL, shallower ACD, narrower ACW, and ACA (all p < 0.05). By Pearson's correlation analysis, SER was negatively associated with ACD, AOD, and TISA. AL was positively associated with ACD, ACW, AOD, and TISA. In the multiple regression analysis, AOD and TISA were associated with deeper ACD, narrower ACW, and longer AL. CONCLUSION: In primary school students, the myopic eyes have deeper AC and wider angle. ACD, ACW, AOD, and TISA all increase with axial elongation. ACA is highly correlated with deeper ACD.

Refraction and ocular biometric parameters in 3-to 6-year-old preschool children : a large-scale population-based study in Chengdu, China.

PURPOSE: To understand the ocular biometric parameters characteristics and refractive errors in 3-to 6-year-old preschool children in Chengdu, China, and to investigate the prevalence of refractive errors. METHOD: A school-based cross-sectional study was conducted in Chengdu from 2020 to2022 with a total of 666 kindergartens. All children were measured by non-cycloplegic autorefraction and uncorrected visual acuity (UCVA) and ocular biometric parameters. Finally, univariate linear regression models were used to analyze the relationship between ocular biometric parameters and refraction. RESULTS: A total of 108,578 preschool children aged 3-6 underwent examinations, revealing a myopia prevalence of 6.1%. The mean axial length (AL), keratometry (K), corneal radius (CR), axial length/corneal radius (AL/CR) Ratio, central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), and vitreous chamber depth (VCD) were 22.35 ± 0.69 mm, 43.35 ± 1.58 D, 7.80 ± 0.28 mm, 2.87 ± 0.08, 533.31 ± 32.51 µm, 2.70 ± 0.28 mm, 3.91 ± 0.27 mm, and 15.20 ± 0.68 mm, respectively. With increasing age, AL, CR, AL/CR ratio, CCT, ACD, LT, and VCD also increased. Regardless of age, males consistently exhibited longer AL, flatter corneal curvature, shallower ACD, thicker CCT, thinner LT, and longer VCD compared to females. AL, K, CR, LT, and VCD all showed significant linear relationships with SE (all P < 0.001) in univariate linear regression analysis after adjusting for gender and age. CONCLUSION: The prevalence of myopia among preschool children aged 3-6 in Chengdu is relatively low. Ocular biometric parameters affecting refractive errors include AL, K, CR, LT, and VCD. The preschool period serves as a critical phase for myopia prevention and control.

Association of myopia and astigmatism with postoperative ocular high order aberration after small incision lenticule extraction.

OBJECTIVE: To investigate the correlation between higher-order aberrations (HOA) after small incision lenticule extraction (SMILE) and the severity of myopia and astigmatism, along with the relevant factors. These findings will provide valuable insights for decreasing the occurrence of HOA after SMILE and enhancing visual quality. METHODS: A total of 75 patients (150 eyes) with myopia and astigmatism who underwent SMILE were categorized into four groups based on the severity of myopia and astigmatism: Myopia Group 1 (Group M1, spherical diopter ranged from -1.00 D to -4.00 D), Myopia Group 2 (Group M2, spherical diopter ranged from -4.10 D to -10.00 D), Astigmatism Group 1 (Group A1, cylindrical diopter ranged from 0 D to -1.00 D), and Astigmatism Group 2 (Group A2, cylindrical diopter ranged from -1.10 D to -3.00 D). A comprehensive assessment was performed to examine the association between HOA and various relevant factors, including a detailed analysis of the subgroups. RESULTS: Group M1 had significantly lower levels of total eye coma aberration (CA), corneal total HOA (tHOA), internal tHOA, and vertical CA ( Z 3 - 1 ) after SMILE than Group M2 (P < 0.05). Similarly, Group A1 had significantly lower levels of total eye tHOA, CA, trefoil aberration (TA), corneal tHOA, TA, and vertical TA ( Z 3 - 3 ) after SMILE than Group A2 (P < 0.05). Pearson correlation analysis indicated a statistically significant positive relationship between the severity of myopia/astigmatism and most HOA (P < 0.05). Subgroup evaluations demonstrated a notable increase in postoperative HOA associated with myopia and astigmatism in Groups M2 and A2 compared with the control group. Lenticule thickness, postoperative central corneal thickness (CCT), postoperative uncorrected distance visual acuity (UDVA), and postoperative corneal Km and Cyl were strongly correlated with most HOA. Age, eyes, and postoperative intraocular pressure (IOP) were only associated with specific HOA. CONCLUSION: HOA positively correlated with the severity of myopia and astigmatism after SMILE. However, this relationship was not linear. HOA after SMILE was influenced by various factors, and additional specialized investigations are required to establish its clinical importance.

Prevalence and characteristics of amblyopia, strabismus, and refractive errors among patients aged 3-16 years in Shanghai, China: a hospital-based population study.

BACKGROUND: Functional visual impairments in children are primarily caused by amblyopia or strabismus. This study aimed to determine the prevalence and clinical profile of amblyopia and strabismus among individuals aged 3-16 years in Shanghai, China. METHODS: From February 2023 to February 2024, this hospital-based, cross-sectional study included data of children who visited the Ophthalmology Department of Shanghai General Hospital. Comprehensive ocular examinations included visual acuity measurement after cycloplegic refraction, slit lamp examination, cover test, and dilated fundus examination. Descriptive statistics were performed to estimate the proportion and clinical characteristics of amblyopia and strabismus. RESULTS: A total of 920 children were enrolled in our study. Among them, 223 (24.24%) children were identified as amblyopia. Unilateral amblyopia occupied 57.85%, and bilateral amblyopia occupied 42.15%. Most participants were within the age range of 5-10 years (75.97% for unilateral amblyopia, and 70.21% for bilateral amblyopia). Anisometropia was the primary cause of unilateral amblyopia (68.99%). Most amblyopic children have high hyperopia (38.76% for unilateral amblyopia, and 39.89% for bilateral amblyopia). 30 (3.26%) children were diagnosed with strabismus, and 19 (63.3%) of them were aged 5-10 years. Seven of the children had both strabismus and amblyopia. CONCLUSION: The proportion of patients with amblyopia and strabismus was determined as 24.24% and 3.26% in our study. Anisometropia was the leading cause of unilateral amblyopia, whereas high hyperopia was a crucial refractive error in the amblyopic population. These findings shed light on further longitudinal studies targeting the age-related changes in amblyopia, strabismus and refraction errors. Therefore, efforts should be made to manage uncorrected refractive errors, amblyopia, and strabismus among children in Shanghai.