Refractive Error Research Articles

Prevalence and association of uncorrected refractive error among Chinese adolescents: a cross-sectional study.

Uncorrected refractive error (URE) is one of the main causes of visual impairments. URE may reduce interaction and learning in the classroom, leading to social isolation, irreversible amblyopia, lack of external knowledge, and restrictions on education and employment opportunities. Our aim was to investigate the prevalence and related factors of URE in adolescents using epidemiological surveys and questionnaire surveys related to lifestyle habits. A cross-sectional school-based study was conducted in Nantong, China, including adolescents 12-19 years of age from 16 schools. URE was defined as presenting visual acuity worse than 6/12 and improving to ≥ 1 lines after correction in either eye. Univariate and multivariate logistic regression analyses were used to investigate specific correlations between URE and related lifestyle parameters. Non-cycloplegic autorefraction was assessed for each adolescent. A total of 2,910 adolescents were analyzed, of which 50.3% (n = 1,465) were male, and 49.7% (n = 1,445) were female. The mean age was 15.23 ± 1.77 years. The overall prevalence of URE was 23.7%. The total prevalence of REC and eREC was 85.1% and 71.7%, respectively, and both of them showed an increasing trend with age (Ptrend = 0.018 and Ptrend = 0.019, respectively). A higher prevalence of URE was related to myopia, anisometropia, and increased daily use of electronic products. Timely visual examination by medical institutions, more extracurricular homework, and older age were protective factors for URE. Among the 689 adolescents with URE, 362 (52.5%) did not receive any refractive correction, and 327 (47.5%) used corrected glasses. URE was highly prevalent among adolescents in China. Myopia was the most important risk factor for URE. The impact of anisometropia and increased daily use of electronic devices on URE was significant. Timely visual examinations by medical institutions served as an effective protective factor against URE. Further research on adjusting intervention strategies is therefore needed to eliminate preventable visual impairments.

Age-specific distribution of oculometric parameters and myopia in children aged 8-12y.

To describe the distribution of ocular biometrics and to evaluate its associations with refractive error and to assess the contribution from ocular parameters to refractive error among Chinese myopic children. This cross-sectional study evaluated subjects aged 8-12y. Keratometry, ocular biometry, and cycloplegic autorefraction were performed on each subject. Spherical equivalent refraction (SER) and ocular biometrics were assessed as a function of age and gender. The Pearson correlation analysis between SER and ocular biometrics was carried out. Multiple linear regression was performed to analyze the association between SER and ocular parameters. A total of 689 out of 735 participants (321 boys, 48.1%) were analyzed, with a mean SER of -2.98±1.47 diopter (D). Axial length (AL), anterior chamber depth (ACD), corneal radius of curvature (CR), horizontal visible iris diameter (HVID), central corneal thickness (CCT) and lens power (LP) showed normal distribution. The AL, AL/CR ratio, ACD and CR increased from 8 to 12y of age, while SER and LP decreased, HVID and CCT remained stable. There was no difference in gender. SER decreased by 0.929 D for every 1 mm increase in AL and decreased by 1.144 D for every 0.1 increase in AL/CR ratio. The Pearson correlation coefficient between SER and AL was -0.538 (P<0.01) and -0.747 (P<0.01) between SER and AL/CR ratio. For the SER variance, AL explained 29.0%, AL/CR ratio explained 55.7%, while AL, CR, ACD and LP explained 99.3% after adjusting for age and gender. The AL, CR, ACD and LP are the most important determinants of myopic refractive error during myopia progression.

Add-on perceptual learning on refractive amblyopia in children.

To evaluate the visual outcomes of standard amblyopic treatment add-on training via perceptual learning in refractive amblyopic children and to identify the risk factors for treatment failure. Retrospective charts were reviewed in children with refractive amblyopia who received standard treatment and add-on Cambridge Visual Stimulator (CAM) training. The add-on CAM group that was enrolled had worn full-corrected glasses for at least 2mo before training. A control group received only the standard treatment. Treatment success was defined as best-corrected visual acuity (BCVA) ≥20/25. The age, sex, initial BCVA, refractive errors, sessions and duration of training, and final BCVA were recorded. A total of 209 children (129 children in add-on CAM group and 80 children in control group) were enrolled. Seventy-six percent of unilateral and 87% of bilateral amblyopic children achieved treatment success. In children with unilateral or bilateral moderate amblyopia, the duration to reach BCVA ≥20/25 was significantly shorter in add-on CAM group than in control group. Poor initial BCVA (P<0.001) and high astigmatism (P=0.007) were risk factors for treatment failure after add-on CAM training. Age, sex, and types of refractive error were not associated with treatment success. Add-on CAM training is an effective strategy for visual improvement and can shorten the treatment course when the effect of standard treatment is limited in amblyopic children.

Frontiers of myopia research in the 21st century: A bibliometric analysis of the top 100 most influential articles in the field.

Myopia is the most common refractive error worldwide, contributing not only to visual impairment but also serving as a potential risk factor for various severe ocular diseases. Its impact on patients' quality of life and health is significant and imposes substantial socioeconomic burdens. In this study, we analyzed the top 100 most cited articles related to myopia published in the Web of Science Core Collection database from January 2000 to February 2024. Using data visualization tools CiteSpace, VOSviewer, and Scimago Graphica, we identified the most influential research papers and academic journals in the field of myopia. The top 100 most influential articles were published in 25 renowned journals across 30 countries, with Investigative Ophthalmology & Visual Science being the most prolific. Ophthalmology had the highest total citation frequency, while The Lancet had the highest average citation frequency. The United States and the National University of Singapore were the top countries and institutions with the most published papers. The 3 major research directions are Ophthalmology, Medicine, General & Internal, and Genetics & Heredity. The top 5 co-occurring keywords were refractive error, risk factors, prevalence, eye growth, and form-deprivation myopia. Cluster analysis results highlighted focal points such as retinal detachment, high myopia, and contrast sensitivity, indicating potential future research trends. Prospective research directions include investigating the pathogenesis of myopia, updating diagnostic technologies, and identifying risk genes for myopia and its complications.

Compliance and Determinants of Spectacle Wear Among Moroccan Adults Residing Beni-Mellal Khénifra Region.

Ensuring a high level of adherence to wearing spectacles is essential to preserve eye health and achieve optimal vision correction. Comprehending the factors influencing adherence to wearing spectacles can inform strategies to improve eye care outcomes. This study aimed to assess the prevalence and factors influencing adherence to wearing spectacles among Moroccan adults residing the Beni-Mellal Khenifra region. A cross-sectional interview survey was conducted involving 389 adult spectacle wearers. Participants were recruited through a multilevel random sampling technique and interviewed using a structured questionnaire. This questionnaire collected data on demographics, spectacle prescription, usage patterns, and barriers to compliance. Compliance was assessed based on self-reported frequency and duration of spectacle wear according to the prescription. Possible factors influencing the wearing of spectacles were investigated using both univariate and multivariate regression models. This study revealed that 57.6% of participants adhered to the recommended use of spectacles. Factors associated with compliance were higher education level, longer duration of spectacle use, awareness about the importance of spectacle wear, absence of a family history, specific refractive error types, and increased severity of refractive errors. Participants reported various reasons for not adhering to the recommended use of spectacles, with the most common being forgetfulness, perceiving improved vision without spectacle, discomfort while wearing spectacle, difficulty adapting to spectacle, and loss of spectacle. Given the high prevalence of non-compliance to spectacle wear among adults in the Beni-Mellal Khenifra region, it is evident that additional efforts are required to improve understanding and education regarding the advantages of consistent spectacle usage. Targeted educational and awareness initiatives have the potential to substantially enhance adherence rates and consequently improve visual health outcomes in the region.

Parents' Knowledge and Attitudes Toward Pediatric Ophthalmic Disorders in Saudi Arabia: A Cross-Sectional Study.

Recognizing pediatric eye health issues at an early stage, along with ensuring that parents are well informed, is crucial. This study measures parents' knowledge and perspectives on pediatric ophthalmic disease. The study utilized a cross-sectional design, and participants included Saudi parents of children residing in Saudi Arabia. Data were collected using a pre-validated self-administered questionnaire with a scoring system. Sociodemographic characteristics and factors associated with knowledge/attitude were collected and analyzed. Initially, 425 respondents participated in this study. Excluding the participants whose work was related to healthcare and those with incomplete data yielded 370 responses on which the subsequent analyses were performed. The analysis revealed that only half of the parents recognized the need for annual eye examinations for children. Most of them showed gaps in knowledge regarding the frequency of routine eye exams and indicators of visual problems. Notably, parents with good/excellent knowledge were more proactive in their eye care practices, such as adherence to recommended eye examination schedules and accepting corrective measures like glasses for common conditions such as refractive errors and amblyopia. However, parental willingness to permit surgical interventions did not correlate significantly with their level of knowledge, signaling the influence of other factors. In conclusion, this study underscores the need for enhanced public health education to improve parental awareness of pediatric eye diseases in Saudi Arabia. Given the link between knowledge and proactive eye health practices, targeted interventions should distribute comprehensive, culturally sensitive information accessible to all demographics.

Imprint of preterm birth with very low birth weight on optic disc OCT in adulthood-A two-country birth cohort study.

To determine the pattern, degree and prevalence of optic disc optical coherence tomography (OCT) alterations in adults born preterm with very low birth weight (VLBW; birth weight < 1500 g). Optic disc OCT was assessed in 98 VLBW participants and 139 term-born controls from birth cohorts in Finland and Norway at the mean age of 36 years. The participants had not been treated for retinopathy of prematurity and had no diagnosed brain abnormality. OCT assessment included parameters for optic disc size, neural rim and peripapillary retinal nerve fibre layer thickness (pRNFLT), and for the foveal developmental stage. Background data, visual acuity, refractive error and intraocular pressure were recorded. In the VLBW group, optic disc neural rim and pRNFLT were significantly decreased, most frequently in the nasal and inferior sectors. In 40% (95% CI: 33-47) of the VLBW eyes, nerve fibre thickness of at least one optic disc sector was below the fifth percentile of the control group, including 9% (95% CI: 6-14) subgroup falling below the first percentile, that is, clinically below normal limits. VLBW participants with nerve fibre thickness below the fifth percentile did not differ by perinatal data or foveal developmental stage from the other VLBW participants. All participants had normal visual acuity. A moderate decrease of the optic disc neural rim and pRNFLT is frequently seen in clinically healthy adults born preterm with VLBW. Awareness of the VLBW-related optic disc nerve fibre shallowness especially in the inferior and nasal sectors is important while evaluating acquired optic disc pathology in adulthood.

Cone dysfunction in ARR3-mutation-associated early-onset high myopia: an electrophysiological study

BackgroundMyopia-26, a Mendelian form of early-onset high-myopia (eoHM) caused by mutations in the X-chromosomal ARR3 gene and predominantly affecting females, curiously, may provide an alternative route of investigation to unveil retinal mechanisms underlying pathological eye growth. We conducted a case-control cross-sectional prospective electrophysiological study in genetically characterized Myopia-26 patients (ARR3 heterozygous symptomatic females) compared with high myopes harboring intact ARR3 alleles and one carrier hemizygous male.ResultsParticipants were 26 volunteers: 10 healthy control females (E-CTRL, mean age = 31.5 ± 8.8 years), one healthy control male, one carrier male of the mutant ARR3 allele and 14 female eoHM patients (mean age = 27.0 ± 13.1 years) divided in two groups: seven without (M-CTRL) and seven with (MYP-26) genetic alteration in the ARR3 gene. The clinical evaluation included complete eye screening and full-field electroretinograms (ERGs) recorded from both eyes under mydriasis. Spherical equivalent was comparable (mean=-9.55 ± 2.46 and − 10.25 ± 3.22 for M-CTRL and MYP-26, respectively) and best corrected visual acuity (BCVA) was significantly different between M-CTRL and MYP-26 (1.0 vs. 0.406 ± 0.253, respectively). E-CTRL and M-CTRL showed similar light-adapted flash and flicker ERG amplitudes; however, the prior values were reduced by ~ 35% (a- and b-waves alike), the latter by ~ 55% in the MYP-26 group (F(2, 45) > 21.821, p < 0.00001). Dark-adapted a-wave amplitudes were slightly reduced (by ~ 20%) in all myopic patients compared to E-CTRL, irrespective of the ARR3 genotype (E-CTRL vs. eoHM, p = 0.038).ConclusionsThe cone dysfunction observed in Myopia-26 patients is specifically linked to the mutation of ARR3, and is not the consequence of eoHM, i.e. elongation of the eye. It may play a role in myopic refractive error development through a yet unconfirmed pathomechanism.

Refractive error and ocular alignment in school-aged children from low-income areas of São Paulo, Brazil

BackgroundUncorrected refractive errors and amblyopia are reported as the two main causes of childhood visual impairment and blindness worldwide. Our purpose was to evaluate refractive status, ocular alignment and effective refractive error coverage (eREC) of school-aged children from low-income areas of Sao Paulo city, Brazil.MethodsData from the “Ver na Escola” Project were used for the current study. Children enrolled in the selected schools had an ophthalmic exam including eye alignment assessed by cover test, automatized and subjective dynamic and static refraction. The associations of demographic variables with occurrence and magnitude of refractive errors and eREC were investigated by multiple logistic regressions and multilevel mixed effect models.ResultsA total of 17,973 children (51.12% females) with mean ± sd age 8.24 ± 3.54 years old examined from July 2018 to July 2019, were included in the study. Most of the participants (73%) showed orthoposition of the visual axis for both distance and near. Heterophoria was found in about 25% of participants (N = 4,498), with 71.7% of them (N= 3,222) classified as exophoria. Less than 2% (N = 232) showed strabismus, most of them (N = 160) esotropia. Overall, 1,370 (7.70%) of participants had myopia and 577 (3.24%) had hyperopia. Age was found to be significantly associated with increasing static subjective refraction spherical equivalent (Coefficient: -0.18; 95% Confidence Interval (CI): -0.21 to -0.16; p < 0.001). Female sex (Odds Ratio (OR) = 1.13; 95%CI: 1.01–1.27; p = 0.027) and older age (OR = 1.17; 95%CI: 1.16–1.19; p < 0,001) were significantly associated with myopia diagnosis. Older age decreased the odds of hyperopia (OR = 0.95; 95%CI: 0.93–0.98; p < 0.001). The overall effective refractive coverage was 51.76% and was significantly associated with age group, ranging from 32.25% in children aged 3 to 7 years to 61.35% in children aged 8 to 12 years.ConclusionsMost children have shown eye alignment for both distance and near assessments and no refractive error. Myopia was observed in 7.70% of the population and it was associated with older age and female sex. Hyperopia was observed in 3.24% and was associated with younger age. The overall eREC was 51.76%, significantly associated with age.

Refining delivery and positioning: A modified approach to FIL SSF intraocular lens implantation using the "full reverse" technique.

To present a modified surgical technique for implantation of the sutureless scleral-fixated hydrophilic intraocular lens (FIL SSF). Single surgeon retrospective case series and review of surgical videos with step-by-step technique analysis. Uncorrected and best corrected visual acuity (UCVA and BCVA), refractive error (spherical equivalent), full clinical examination with intraocular pressure (IOP) measurement, endothelial cell density on corneal specular microscopy and macular optical coherence tomography (OCT) were recorded at baseline, 1, 4 and 8 weeks postoperatively. The FIL SSF IOLs were successfully implanted using the so-called "full reverse" technique, having the lens loaded in the injector in an upside-down fashion, as opposed to IOL technical specifications. In all cases, the FIL SSF IOL was properly placed in the ciliary sulcus, well-centered and without signs of tilt. Follow up figures at 2 months are consistent with published data, confirming the potential benefits of the new implantation technique. In our preliminary experience, the "full reverse" technique of the FIL SSF IOL has proven effective in preventing incorrect IOL orientation in 100% of cases. However, larger prospective controlled studies and longer follow up are required to either support or disprove our results.

Effect of Fresnel prism in small-angle esotropia (≤ 20 prism diopters) with fixation preference.

We aimed to investigate the effects of Fresnel prism treatment for small-angle esotropia (≤ 20 prism diopters [PD]) with fixation preference. We included 32 patients with remaining esotropia ≤ 20 PD measured using the simultaneous prism and cover test (SPCT) after full refractive error correction. Fresnel prism was applied to make patients orthotropic with glasses. Treatment was discontinued if remaining esotropia ≤ 4 PD was sustained during two consecutive follow-ups (2-month intervals) or if the angle continued to increase with prism adaptation. Patients were divided into treatment success and failure groups. Treatment success was defined by motor and visual acuity (VA) aspects. Criteria for motor success was residual esotropia ≤ 8 PD in patients with initial esotropia > 8 PD and a 30% decrease of esotropia in those with initial esotropia ≤ 8 PD. VA success was improvement of > 0.2 logMAR in the non-dominant eye. The initial esodeviation angle was 6.92 ± 4.66 PD at distance and 10.53 ± 5.58 at near. The logMAR VA was 0.10 ± 0.13 and 0.26 ± 0.20 in the dominant and non-dominant eye, respectively. Among the 32 patients, 14 showed motor success. Among 26 patients whose VA could be measured, 15 showed VA success. Factors influencing motor success were a small amount of maximum prescribed Fresnel prism, less frequent need for Fresnel prism adaptation, and high percentage of achieving orthotropia with Fresnel prism treatment. VA success was influenced by low frequency of anisometropia and the small amount of maximum prescribed Fresnel prism. Fresnel prism could be a non-invasive treatment option for some patients with small-angle esotropia with fixation preference. What is known The optimal approach for addressing small-angle esotropia is a topic of debate. Not much research has been conducted on Fresnel prism treatment in patients with small-angle esotropia. What is new Motor success and visual acuity improvement were observed in some patients undergoing Fresnel prism treatment. Factors contributing to motor success were the small maximum angle of esodeviation, the less frequent necessity for Fresnel prism adaptation, and the achievement of orthotropia during Fresnel prism treatment. Visual acuity improvement was hindered by the presence of anisometropia and thelarge maximum prescribed amount of Fresnel prism. Fresnel prism treatment can be used as a treatment option for some patients with small-angle esotropia with fixation preference.

Patterns of refractive errors and visual function in school-going children in South Africa

Background: Uncorrected refractive error is the most significant contributor of VI in children and is usually detected through vision screenings or scheduled eye and vision examinations conducted among school children.Aim: To describe patterns of refractive errors (RE), visual function and amblyopia in school-going children.Setting: Mankweng, Polokwane, South Africa.Methods: Retrospective chart reviews were conducted on 837 clinical record cards of children attending selected schools and who were screened between 2019 and 2021 at the University of Limpopo Optometry clinic. Purposive sampling was used to sample the clinical record cards.Results: About 134 children (16%) reported blurred vision, 197 (23.5%) failed distance visual acuity screening, while 173 (20.7%) had RE. Myopia among 168 (9.6%) children was the most common RE, followed by astigmatism and hyperopia at 60 (4.70%) and 28 (4.4%), respectively. Furthermore, 14 (1.7%) children had anisometropia. Amblyopia, colour vision deficiency and contrast sensitivity were also detected at prevalence rates of 4.4%, 9.8% and 8.2%, respectively.Conclusion: Vision screenings and regular comprehensive eye examinations are commonly conducted to detect and manage REs to prevent or delay the onset of amblyopia and strabismus. Children had a high prevalence of RE and amblyopia, which is similar to global estimates.Contribution: To describe the pattern of REs, amblyopia and visual function, which is critical to understand the prevalence of amblyopia and associated conditions. Knowing the patterns of these conditions may provide an impetus for the implementation of strategies such as vision screenings and vision examinations in schools.

Prevalence of dry eye disease symptoms, associated factors and impact on quality of life among medical students during the pandemic

This cross-sectional study aimed to evaluate the prevalence of dry eye disease (DED) symptoms, their associated factors, and the impact on quality of life (QOL) and mental health among medical students during the COVID-19 pandemic using online surveys. Participants completed questionnaires covering demography, medical history, and personal data. The Thai version of the Dry Eye-related Quality-of-Life Score (DEQS-Th) was used for DED screening. The QOL and mental health challenges (support, coping, stress, and depression) were evaluated by the EuroQoL-5 dimensions-5 levels (EQ-5D-5L) and Thymometer questionnaires. A total of 449 participants were analyzed, with a mean age of 21.8 years and 61.5% female. The prevalence of DED symptoms was 60.4% (95%CI 55.7–64.8). The DEQS-Th score, the EQ-5D-5L score, and all aspects of mental health challenges were significantly worse in DED participants compared to non-DED participants. Associated factors for DED symptoms included preexisting DED (p = 0.001), refractive errors (p = 0.007), allergic conjunctivitis (p = 0.001), artificial tears use (p < 0.001), and decreased EQ-5D-5L score (p < 0.001). This study highlighted the high prevalence of DED symptoms among medical students during the pandemic and its negative impact on QoL and mental health. Notably, female gender, contact lens wear, screen time, and mask-wearing duration were not associated with DED symptoms.

Analysis of factors influencing refractive error in Fuchs eyes undergoing Descemet membrane endothelial keratoplasty triple procedure

PurposeTo evaluate the accuracy of current intraocular lens (IOL) formulas and identify factors influencing mean error in eyes undergoing Descemet membrane endothelial keratoplasty (DMEK) triple procedure, that is, DMEK combined...

One-year outcomes after intraocular collamer lens implantation in hyperopic astigmatism: a retrospective single-center study.

Astigmatism is the most prevalent refractive error among children and adults, and it can lead to visual impairment if left uncorrected. The management of compound hyperopic astigmatism is more challenging. This study presents the 12-month outcomes of toric implantable collamer lens (ICL) implantation in eyes with hyperopic astigmatism. This interventional case series included patients with simple or compound hyperopic astigmatism who underwent toric ICL implantation. All eligible individuals underwent a detailed ocular examination. Uncorrected and corrected distance visual acuities (UDVA and CDVA, respectively), intraocular pressure, and manifest and cycloplegic refraction results were documented. Pentacam corneal tomography was performed to assess the central corneal thickness, iridocorneal angle width, and anterior chamber depth. Endothelioscopy was performed to determine endothelial cell density. The ICL V4b model was implanted in all the included eyes. Safety and efficacy indices were calculated as postoperative CDVA/preoperative CDVA and postoperative UDVA/preoperative CDVA, respectively. Twenty-six eyes with low-grade simple or compound hyperopic astigmatism were included. All eyes experienced a significant improvement of four lines in postoperative UDVA (P < 0.001), and their postoperative CDVA remained stable at the 12-month follow-up (P > 0.05). The safety and efficacy indices were 1.0. None of the eyes lost two or more lines of CDVA; in 81% of the eyes, CDVA was unchanged, and the proportion of eyes with 20/30 or better postoperative UDVA was identical to that with 20/30 or better preoperative CDVA (81% for each). The mean manifest spherical equivalent at the 12-month postoperative visit had significantly improved (P < 0.001). The percentages of eyes with postoperative spherical equivalent within ± 0.50 D and ± 1.00 D were 81% and 96%, respectively. The postoperative refractive cylinder improved significantly (P < 0.05), and the percentage of eyes with refractive cylinder within ± 0.50 DC and ± 1.00 DC were 50% and 77%, respectively. Our outcomes indicate that toric ICL implantation is safe and effective for managing low-grade simple or compound hyperopic astigmatism. The proportion of eyes with 20/30 or better postoperative UDVA was identical to that with a 20/30 or better preoperative CDVA. The manifest spherical equivalent and refractive cylinder were significantly reduced. No serious safety concerns were observed. Further prospective large-scale studies with a wide range of ages and grades of hyperopic astigmatism are required to verify these preliminary outcomes.

The status and changing trend in the burden of refractive errors in China from 1990 to 2019

Objective: To comprehend the status and changing trend in the burden of refractive errors in China from 1990 to 2019, and to furnish data-driven support for the formulation of rational strategies in refractive error prevention and control. Methods: Using the Global Burden of Disease Database 2019, data on refractive error prevalence and years lived with disability (YLD) in China from 1990 to 2019 were extracted and their standardized rates were calculated. The trend of refractive error prevalence, age, period, and gender was analyzed using joinpoint regression models. Results: From 1990 to 2019, the number of cases, prevalence rate, and YLD rate of refractive errors in China showed an upward trend, which was consistent with global trends. However, the magnitude of the increase in these parameters was higher than the global average. Conversely, the age-standardized prevalence rate and age-standardized YLD rate demonstrated a declining trend, which was also consistent with global trends, but the reduction rate was less pronounced compared to global levels. Notably, all indicators for females, including prevalence and YLD, exceeded those of males. The prevalence and YLD rates of refractive errors in China increased with age. The older individuals had higher rates compared to younger individuals. In 1990, the highest prevalence and YLD rates were found in the ≥70 years group, while the lowest rates were in the <5 years group. The age group with the most substantial increase in the burden of refractive errors was the 15 to 49 years population, which remained consistent during the three decades. The joinpoint regression analysis results revealed a stage-wise fluctuation in the age-standardized prevalence and YLD rates of refractive errors in China from 1990 to 2019. Specifically, the age-standardized prevalence rate increased by 0.765% from 1990 to 2001, decreased by 0.963% from 2001 to 2014, increased by 4.214% from 2014 to 2017, and decreased by 3.029% from 2017 to 2019. In contrast, the age-standardized YLD rate decreased by 0.113% from 1990 to 1995, increased by 2.252% from 1995 to 2000, decreased by 1.102% from 2000 to 2014, increased by 4.326% from 2014 to 2017, and decreased by 5.090% from 2017 to 2019. Conclusions: The standardized prevalence of refractive errors and the standardized YLD rate in China showed a downward trend, which was less than the global average level, but the disease burden was still heavy. Gender and age emerged as significant influencing factors for the prevalence of refractive errors and YLD. It is imperative to enhance efforts in the prevention and treatment of refractive errors among the middle-aged and elderly population. Attention should also be directed towards the increasing burden in the<50 years population.

Dynamic BMP gene expression regulation in chick RPE during recovery from short term optical defocus and form-deprivation.

This study investigated the differential gene expression of BMPs in chick retinal pigment epithelium (RPE) during recovery from short term exposure to optical defocus and form-deprivation (FD) treatments. 14-day old White-Leghorn chicks wore either monocular +10 or -10 D lenses, or diffusers for 2 or 48 h, after which eyes were allowed unobstructed vision for up to 96 h. Over this recovery period, refractive errors and choroidal thickness (ChT) were tracked using retinoscopy and high-frequency A-scan ultrasonography. Real-time PCR was used to examine the expression of BMP2, 4, and 7 genes in RPE samples collected 0, 15 min, 2, 24, 48, and 96 h after the termination of treatments. Expression levels in treated eyes and their contralateral control eyes were compared. After the termination of the lens and diffuser treatments, eyes gradually recovered from induced shifts in refractive error. With all three treatments, ChT changes reached statistical significance after 48 h of treatment, be it thinning with the -10 D lens and diffuser treatments (-0.06 ± 0.03mm, p < 0.05; -0.11 ± 0.04 mm, p < 0.05, resp.), or thickening with the +10 D lens (0.31 ± 0.04 mm, p < 0.001). BMP2 gene expression was rapidly upregulated in eyes wearing the +10 D lens, being statistical significance after 2 h, as well as 48 h of treatment. With the 2 h treatment, the latter gene expression pattern persisted for 15 min into the recovery period, before decreasing to the same level as that of contralateral control eyes, with a short-lived rebound, i.e., upregulation, 24 h into the recovery period. With the longer, 48 h treatment, BMP2 gene expression decreased more gradually, from 739 ± 121% at the end of the treatment period, to 72 ± 14% after 48 h of recovery. Two and 48 h of both -10 D and FD treatments resulted in BMP2 gene expression downregulation, with the time taken for gene expression levels to fully recover varying with the duration of initial treatments. In both cases, BMP2 gene expression downregulation persisted for 15 min into the recovery period, but reversed to upregulation by 2 h. Similar gene expression patterns were also observed for BMP4, although the changes were smaller. The observed changes in BMP gene expression in chick RPE imply dynamic, albeit complex regulation, with the duration of exposure and recovery being critical variables for all three types of visual manipulations. This study provides further evidence for a role of the RPE as an important signal relay linking the retina to the choroid and sclera in eye growth regulation.

The relationship between contact lens ultraviolet light transmittance and myopia progression: a large-scale retrospective cohort study.

The prevalence of myopia is increasing dramatically around the world, and many studies have suggested the possibility that ultraviolet (UV) light is effective to prevent the onset and progression of myopia. However, UV is a risk factor for diseases that cause refractive errors such as cataract and pterygium. In this study, we evaluated the relationship between UV exposure and myopia progression. The dataset consisted of a total of 337 396 eyes of patients in the 12-to-29-year age range, who were prescribed soft contact lenses (SCL) for refractive error at Okada Eye Clinic in Japan between 2002 and 2011. They were tracked over a five-year period and did not change the type of SCL. In this retrospective cohort study based on medical records, we divided patients into two groups, one prescribed SCL with UV protection (UV-SCL), and another prescribed SCL without UV protection (UV+SCL). Change in refractive power over five years was measured and results compared. It was -0.413 diopter (D) in the UV-SCL group and -0.462 D in the UV+SCL group. Thus, the progression of myopia was slower in the UV-SCL group. The results were also analyzed separately by gender and degree of myopia at the time of initial prescription, which all showed significant differences (P<0.001). Results suggest that UV exposure may advance myopia. Further research is needed to investigate the underlying mechanisms that could explain this.

Investigation of the Reproducibility of Portable Optical Coherence Tomography in Diabetic Macular Edema

Background: Diabetic macular edema (DME) causes vision impairment and significant vision loss. Portable optical coherence tomography (OCT) has the potential to enhance the accessibility and frequency of DME screening, facilitating early diagnosis and continuous monitoring. This study aimed to evaluate the reliability of a portable OCT device (ACT100) in assessing DME compared with a traditional stationary OCT device (Cirrus 5000 HD-OCT plus). Methods: This prospective clinical investigation included 40 eyes of 33 patients with DME. Participants with significant refractive errors (myopia &gt; −6.0 diopters or hyperopia &gt; +3.0 diopters), vitreous hemorrhage, tractional retinal detachment, or other ocular diseases affecting imaging were excluded. Spectral-domain OCT was performed by a single examiner using both devices to capture macular volume scans under mydriasis. Central macular thickness (CMT) was evaluated using the analysis software for each device: Cirrus used version 6.0.4, and ACT100 used version V20. We analyzed inter-evaluator and inter-instrument agreements for qualitative assessments of the intraretinal fluid (IRF), subretinal fluid (SRF), and epiretinal membrane (ERM) using Cohen’s kappa coefficient, whereas quantitative CMT assessments were correlated using Spearman’s correlation coefficient. Results: Substantial inter-evaluator agreement for IRF/SRF (κ = 0.801) and ERM (κ = 0.688) with ACT100 and inter-instrument agreement (κ = 0.756 for IRF/SRF, κ = 0.684 for ERM) were observed. CMT values measured using ACT100 were on average 29.6 μm lower than that of Cirrus (285.8 ± 56.6 vs. 315.4 ± 84.7 μm, p &lt; 0.0001) but showed a strong correlation (R = 0.76, p &lt; 0.0001). Conclusions: ACT100 portable OCT demonstrated high reliability for DME evaluations, comparable to that of stationary systems.

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.