OBJECTIVE: The objective of this study is to investigate the potential influence of refractive error on Video Head Impulse Test outcomes.
METHODS: Eighty-two patients were included in the study, and all patients underwent video head impulse testing. Patients were divided into four groups according to their refractive error: myopia, myopia-astigmatism, astigmatism, and emmetropia as control.
RESULTS: Patients with myopia are younger than patients with astigmatism and controls; similarly, patients with myopia-astigmatism are younger than patients with astigmatism. The right and left lateral, anterior, and posterior gain values were statistically significantly lower in the control group compared with myopia and myopia-astigmatism patients (p < 0.05). There was a statistically significant relationship between the right and left lateral, anterior, and posterior gain values and the degree of myopia in the patients (p < 0.05).
CONCLUSIONS: The results of the Video Head Impulse Test gain in myopia patients are higher than that in patients without refractive error. In addition, age may have an effect on gain values. It is important to consider this factor when evaluating the results of the Video Head Impulse Test in patients, and corrections should be made if necessary.
METHODS: Level 3 Laryngoscope, 2024.

OBJECTIVE: To investigate the refractive error profile and progression in infants with different stages of ROP, without ROP, and those who received laser treatment for ROP.
METHODS: This retrospective study included the data from 838 infants (baseline mean age 3.7 ± 5.4 months) who had premature birth. Among these, 433 infants had one of the stages of ROP and 405 had no ROP. Infants with ROP were sub-divided into stage 1 (n = 76), stage 2 (n = 142), and stage 3 (n = 136) and aggressive posterior ROP, (APROP, n = 79). They were further categorized into those who received treatment (n = 213) and with no treatment for ROP (n = 220). Data from a subset of 117 infants was used to assess the 1-year change in the refractive error. Myopia was defined as spherical equivalent refraction (SER) <-0.50 diopters (D). Eyes with retinal detachment were excluded.
RESULTS: Higher percentage of myopia was found in infants with ROP (39.7%) than no-ROP (19.8%), and it increased with severity of ROP: stage 1: 19.7%, stage 2: 33.8%, stage 3: 45.6%, and 59.5% in APROP. Percentage of myopia doubled in those who underwent treatment for ROP (54.5%) compared to no-treatment group (25.5%). Mean (± SEM) change in SER after 1 year was significantly greater in infants with APROP -4.55 ± 1.38 D and stage 3 ROP -2.28 ± 0.57 D compared to other stages and no-ROP.
CONCLUSIONS: Myopia was found to be more prevalent in preterm infants in general, and more in the presence of ROP. Preterm infants without or with any form of ROP, particularly those with severe form of ROP and those who received treatment require meticulous periodic refractive error assessment.

UNASSIGNED: Astigmatism is closely associated with myopia progression, vision loss, eye fatigue and amblyopia, which seriously endangers children\'s eye health. This study aims to investigate the prevalence and characteristic distribution of astigmatism in children in Langzhong City, providing valuable insights for allocating resources and develop prevention and control strategies.
UNASSIGNED: A cross-sectional study and random sampling survey were conducted. Between January and November 2021, 21,415 students aged 5 to 13 years from 14 primary schools in Langzhong City underwent non-cycloplegic refractive testing using autorefraction. The data on myopia were analyzed using SPSS (Statistical Package for the Social Sciences) version 23.0.
UNASSIGNED: The inclusion criterion was set at an absolute astigmatism value of ≥0.50D. Among the 21,415 children studied, 61.70% were found to have astigmatism. The prevalence of astigmatism varied significantly across different grades (χ2=501.414, P<0.001). The predominant types of astigmatism were mild astigmatism (0.50-1.00D) and with-the-rule astigmatism. Mixed astigmatism was primarily observed in children in grades 1 and 2, while compound myopic astigmatism was more common in children in grades 3 to 6. These differences were statistically significant. As the degree of astigmatism increased, the proportions of against-the-rule astigmatism, oblique astigmatism, compound myopic astigmatism, and simple hyperopic astigmatism decreased, whereas the proportions of with-the-rule astigmatism, mixed astigmatism, and compound hyperopic astigmatism increased.
UNASSIGNED: The prevalence of astigmatism among school-age children aged 5 to 13 years in northeast Sichuan is notably high, with compound myopic astigmatism and with-the-rule astigmatism being the most common types. Regular refractive examinations are crucial for the early detection and management of astigmatism.

OBJECTIVE: This systematic review and meta-analysis aims to assess the refractive outcomes of the Yamane technique for intrascleral fixation of intraocular lenses (SF-IOL) and compare the predictive ability of the various intraocular lens power calculation formulae commonly used in conjunction with the technique.
METHODS: A literature search was conducted in the Medline, Scopus, and Cochrane Library databases for articles published from January 2014 to May 2023. Studies that met the predetermined inclusion criteria were included and subjected to analysis. The primary outcome evaluated was the refractive predictive error, defined as the difference between predicted refraction and post-operative manifest refraction.
RESULTS: Eleven studies met the inclusion criteria, with a cumulative sample size of 615 patients (mean age: 66.6 years). Various IOL formulae were used, with SRK/T being the most frequently adopted formula. The overall mean refractive predictive error for all formulae combined was -0.02 D, which was not statistically significant (p = 0.99). Subgroup analysis for individual formulae also showed no significant difference from predicted error for any formula (p > 0.05).
CONCLUSIONS: The Yamane technique for SF-IOL shows promising refractive outcomes, and the choice of IOL power calculation formula should be tailored based on patient characteristics and surgeon preference. No formula demonstrated superior predictive ability over others. Further research is needed to develop formulae specifically for eyes with secondary aphakia and poor capsular support.

In this study, we aimed to validate a novel light field virtual reality (LFVR) system for estimating refractive errors in the human eye. Fifty participants with an average age of 22.12 ± 2.2 years (range 20-30 years) were enrolled. The present study compared spherical equivalent (SE) and focal line measurements (F1 and F2) obtained by the LFVR system with those obtained by established methods, including closed-field and open-field autorefractors, retinoscopy, and subjective refraction. The results showed substantial agreement between the LFVR system and the traditional methods, with intraclass correlation coefficients (ICC) for SE ranging from 82.7% to 86.7% (p < 0.01), and for F1 and F2 from 80.7% to 86.4% (p < 0.01). Intra-repeatability for F1 and F2 demonstrated strong agreement, with ICC values of 88.8% and 97.5%, respectively. These findings suggest that the LFVR system holds potential as a primary tool for refractive error measurement in optical care, offering high agreement and repeatability compared to conventional methods.

This study explored the potential of telemedicine integration into the eye health ecosystem with an aim of scaling effective refractive error coverage in Kenya. This exploratory study was conducted telephonically and through online interviews with key opinion leaders, ophthalmologists, optometrists, ophthalmic clinical officers, optical technicians and beneficiaries of the optical technician\'s services in rural areas. A telemedicine workflow was developed and validated based on the comments from the key opinion leaders using the Delphi technique. Quantitative and qualitative data were analysed using SPSS and NVivo Software respectively. All of the key opinion leaders agreed that telemedicine is relevant in the eye health ecosystem and recognition of primary vision technicians is critical for effective telemedicine integration. The reasons for the need of telemedicine integration were categorized into; good relationship, organized refractive error service delivery, convenience and availability and cost reduction. The possible factors influencing integration of telemedicine identified were categorized into cost, unwillingness, dominance, perception, lack of technical team, policies and network coverage. The limited human resources in the eye health ecosystem in developing countries cannot effectively deliver refractive error services to the growing population. Hence, integration of telemedicine and establishment of policies recognizing telemedicine are desirable to strengthen task shifting and scale effective refractive error coverage.

Individuals with Down syndrome are known to have a greater prevalence of ocular conditions such as strabismus, nystagmus, elevated refractive error, poor accommodative function, elevated higher-order optical aberrations and corneal abnormalities. Related to these conditions, individuals with Down syndrome commonly have reduced best-corrected visual acuity at both far and near viewing distances across their lifespan. This review summarises the various optical sources of visual acuity reduction in this population and describes clinical trials that have evaluated alternative spectacle prescribing strategies to minimise these optical deficits. Although refractive corrections may still have limitations in their ability to normalise visual acuity for individuals with Down syndrome, the current literature provides evidence for eye care practitioners to consider in their prescribing practices for this population to maximise visual acuity. These considerations include accounting for the presence of elevated higher-order aberrations when determining refractive corrections and considering bifocal lens prescriptions, even for young children with Down syndrome.

BACKGROUND: Assessing refractive errors under cycloplegia is recommended for paediatric patients; however, this may not always be feasible. In these situations, refraction has to rely on measurements made under active accommodation which may increase measurements variability and error. Therefore, evaluating the accuracy and precision of non-cycloplegic refraction and biometric measurements is clinically relevant. The Myopia Master, a novel instrument combining autorefraction and biometry, is designed for monitoring refractive error and ocular biometry in myopia management. This study assessed its repeatability and agreement for autorefraction and biometric measurements pre- and post-cycloplegia.
METHODS: A prospective cross-sectional study evaluated a cohort of 96 paediatric patients that underwent ophthalmologic examination. An optometrist performed two repeated measurements of autorefraction and biometry pre- and post-cycloplegia. Test-retest repeatability (TRT) was assessed as differences between consecutive measurements and agreement as differences between post- and pre-cycloplegia measurements, for spherical equivalent (SE), refractive and keratometric J0/J45 astigmatic components, mean keratometry (Km) and axial length (AL).
RESULTS: Cycloplegia significantly improved the SE repeatability (TRT, pre-cyclo: 0.65 D, post-cyclo: 0.31 D). SE measurements were more repeatable in myopes and emmetropes compared to hyperopes. Keratometry (Km) repeatability did not change with cycloplegia (TRT, pre-cyclo: 0.25 D, post-cyclo:0.27 D) and AL repeatability improved marginally (TRT, pre-cyclo: 0.14 mm, post-cyclo: 0.09 mm). Regarding pre- and post-cycloplegia agreement, SE became more positive by + 0.79 D, varying with refractive error. Myopic eyes showed a mean difference of + 0.31 D, while hyperopes differed by + 1.57 D. Mean keratometry, refractive and keratometric J0/J45 and AL showed no clinically significant differences.
CONCLUSIONS: Refractive error measurements, using the Myopia Master were 2.5x less precise pre-cycloplegia than post-cycloplegia. Accuracy of pre-cycloplegic refractive error measurements was often larger than the clinically significant threshold (0.25 D) and was refractive error dependent. The higher precision compared to autorefraction measurements, pre- and post-cycloplegia agreement and refractive error independence of AL measurements emphasize the superiority of AL in refractive error monitoring.

This study describes the eye health of newly arrived refugees attending a state-funded health service in Adelaide, South Australia, helping to address the paucity of data on the eye health of refugees. Patients attending the Refugee Health Service undergo comprehensive assessment by an on-site optometrist with accredited interpreters if they have eye symptoms, personal or family history of eye disease, or visual impairment (using World Health Organization definitions). A retrospective audit of this service was performed to obtain patient demographics, presenting best-corrected distance visual acuity (better-seeing eye), diagnoses, and management. In 2017-2018, 494 of the 1400 refugees attending the service underwent an optometry assessment (age range 1-86 years, mean age 33.1 ± 18.6 years, 53% female). Regions of origin included the Middle East (25%), Bhutan (24%), Afghanistan (22%), Myanmar (15%), and Africa (14%). Of the 124 cases of visual impairment, 78% resolved with corrective lenses and 11% were due to cataracts. Ophthalmology follow-up was required for 56 (11%) patients, mostly for cataracts (22 patients). Newly arrived refugees have high rates of visual impairment from refractive error and cataracts. Integration of optometry and state-based refugee health services may improve the timely detection and treatment of these conditions.

UNASSIGNED: Local retinal oxygen saturation is a research technique, which has the potential as a biomarker for diabetes. However, normative data has not been established. This study examined differences in oxygen saturation around the macula and characterizes the relationship between age, race, refractive error (RE), sex, blood pressure (BP), prediabetic status and oxygen saturation.
UNASSIGNED: Fifty-nine subjects aged 22-69 (38.8 ± 14.7 years) were included who were racially diverse and with equal gender distribution. None had eye disease. Oxygen saturation was taken with the Zilia Ocular in 4 locations around the macula 3.1 degrees from the fovea and they were also averaged. BP, RE, and HbA1c were noted. Regression analyses for oximetry and other factors were completed as were t-tests with multiple comparison corrections.
UNASSIGNED: There were significant variations in oximetry measures by race, with higher pigmentation levels associated with lower oximetry values (p < 0.01). There was no relationship between oximetry and sex (p = 0.34), RE (p = 0.67), BP (systolic p = 0.61, diastolic p = 0.71) nor prediabetic status (p = 0.87). Oximetry was associated with age when controlling for race (P < 0.002). Nasal-temporal variations showed nasal oximetry to higher than temporal measures (P < 0.01).
UNASSIGNED: This study revealed race/pigmentation is an important influence on oximetry measures. Retinal location also caused variations, likely due to proximity to larger vessels nasally. No differences in sex, RE nor BP were observed to alter local oxygen saturation. However, age was correlated when considered with race. This study will inform our future work in different disease states and is an important first step in evaluating this technology.
This study evaluates a new research instrument (Zilia Ocular) which measures how much oxygen is in the very small blood vessels of the retina. Our group wanted to evaluate healthy people to find out if the measurements the instrument takes are different in different sexes, ages, races, glasses prescriptions and blood pressures. We also looked at if they were changed in people with prediabetes and if it is different in different locations on the retina. We found that the measures are different in different races and ages. The measures also change with location in the eye. The other factors did not change the measurements of oxygen saturation on this instrument. We need to know this information because we want to detect changes in the retina in diabetes in diverse patient groups; however, we need to know about normal variations to better understand and collect that data.