Positive Relative Accommodation Research Articles

The relationship between accommodative and binocular function with myopia progression in myopic children undergoing orthokeratology

PurposeTo determine the relationship between changes in accommodative and binocular function with myopia progression in myopic children over a two-year follow-up period, and to determine when changes in visual functions stabilized after switching from spectacles to orthokeratology (Ortho-K). MethodsThis prospective, self-controlled study followed thirty-six participants (aged 8–14 years) for two years after they switched from spectacles to Ortho-K. Accommodative and binocular function were assessed prior to and 1, 3, 6, 12, 18 and 24 months after commencing Ortho-K. Measurements included accommodative amplitude, accommodative response, accommodative facility, accommodative convergence/accommodation (AC/A), ocular alignment, positive relative accommodation (PRA), negative relative accommodation (NRA), horizontal vergence range, reading ability and stereoacuity. Myopia progression was quantified by the change in axial length. ResultsOcular alignment, monocular and binocular accommodative facility, and PRA stabilized after 1 month. The distance blur point in the convergence range, the distance break and recovery point in the divergence range, accommodative amplitude, calculated AC/A, stereoacuity and reading ability stabilized within 6 months. After two years of Ortho-K, NRA significantly increased (p = 0.044), while it showed no significant difference after one-year of lens wear (p = 0.49). The distance break point in the convergence range showed no significant difference (p = 0.20), but significantly decreased after one-year (p = 0.005). There were no significant correlations between the change in axial length with changes in accommodative or binocular function (p > 0.05). ConclusionAccommodative and binocular function changed significantly after switching from spectacles to Ortho-K and most of the parameters stabilized within the first 6 months. There was no association between the change in accommodative or binocular function and myopia progression.

Factors affecting long-term myopic regression after corneal refractive surgery for civilian pilots in southwest China

BackgroundThe purpose of this study was to analyze myopic regression after corneal refractive surgery (CRS) in civilian pilots and to explore the factors that may cause long-term myopic regression.MethodsWe included civilian pilots who had undergone CRS to correct their myopia and who had at least 5 years of follow-up. We collected retrospective data and completed eye examinations and a questionnaire to assess their eye habits.ResultsA total of 236 eyes were evaluated in this study. 211 eyes had Intrastromal ablations (167 eyes had laser in situ keratomileusis, LASIK, 44 eyes had small incision lenticule extraction, SMILE) and 25 eyes had subepithelial ablations (15 eyes had laser epithelial keratomileusis, LASEK and 10 eyes had photorefractive keratectomy, PRK). The mean preoperative spherical equivalent (SE) was − 2.92 ± 1.11 D (range from − 1.00 to -5.00 D). A total of 56 eyes (23.6%) suffered from myopic regression after CRS. Comparisons of individual and eye characteristics between the regression and non-regression groups revealed statistically significant differences in age, cumulative flight time, postoperative SE (at 6 months and current), uncorrected visual acuity (UCVA), accommodative amplitude (AA), positive relative accommodation (PRA), postoperative period, types of CRS and eye habits. Generalized propensity score weighting (GPSW) was used to balance the distribution of covariates among different age levels, types of CRS, cumulative flying time, postoperative period and continuous near-work time. The results of GPS weighted logistic regression demonstrated that the associations between age and myopic regression, types of CRS and myopic regression, continuous near-work time and myopic regression were significant. Cumulative flying time and myopic regression, postoperative period and myopic regression were no significant. Specifically, the odds ratio (OR) for age was 1.151 (P = 0.022), and the OR for type of CRS was 2.769 (P < 0.001). The OR for continuous near-work time was 0.635 with a P value of 0.038.ConclusionsThis is the first report to analyze myopic regression after CRS in civilian pilots. Our study found that for each year increase in age, the risk of civilian pilots experiencing myopic regression was increased. Intrastromal ablations had a lower risk of long-term myopia regression than subepithelial ablations. There is a higher risk of myopic progression with continuous near-work time > 45 min and poor accommodative function may be related factors in this specific population.

The impact of accommodation function on the difference between noncycloplegic and cycloplegic refraction in adult myopes.

To investigate the impact of accommodation function on the difference between cycloplegic and noncycloplegic subjective and automatic refraction in adult myopes. Myopic patients between 18 and 50 years old evaluated at Peking University Third Hospital who underwent cycloplegic and noncycloplegic automatic and subjective refraction were enrolled. Accommodation function, including negative and positive relative accommodation (PRA/NRA) and accommodation response (binocular cross cylinder, BCC) was examined. Of the 3268 individuals enrolled, the mean age was 27.3 ± 6.9 years, and 34.8% of participants were male. The noncycloplegic spherical equivalent (SE) was 0.23 ± 0.29 D and 0.64 ± 0.61 D more myopic than cycloplegic subjective and automatic refraction. Adjusting for associated factors, participants with at least 0.50 D of more myopia SE refraction by noncycloplegic subjective refraction were more likely to be older (odds ratio [OR], 1.029; 95% confidence interval [CI], 1.013-1.045) and with insufficient (OR, 1.514; 95% CI, 1.093-2.096) and excessive (OR, 2.196; 95% CI, 1.538-3.137) NRA value. The automatic refraction SE difference of at least 1.00 D more myopia was more likely to be found in individuals with older age (OR, 1.036; 95% CI, 1.022-1.050) and accommodative lead (OR, 1.255; 95% CI, 1.004-1.568). A quarter of adult myopes had at least 0.50 and 1.00 D of subjective and automatic SE difference with cycloplegia. The accommodation function significantly affects the difference between cycloplegic and noncycloplegic refraction. Investigating the differences in refraction measurement guarantees the proper use of cycloplegia in adults for myopia correction.

Accommodation and Binocular Vision in Children with Myopic Anisometropia.

To assess the differences in accommodation and binocular vision in children with myopic anisometropia and determine the correlation with anisometropia. A total of 110 patients with myopia aged 8-15 years were recruited from June 2021 to February 2022 from the Affiliated Hospital of Xuzhou Medical University. Based on the interocular differences of spherical equivalent refraction, patients were divided into the isometropia (35 children), low anisometropia (LA group, 42 children), and high anisometropia (HA group, 33 children). The variables assessed were refraction, heterophoria, amplitude of accommodation (AMP), accommodative response (AR), gradient AC/A, positive and negative relative accommodation (PRA/NRA), and near stereopsis in the three groups. Pearson's correlation coefficient tests were used to investigate the possible association between each parameter and interocular differences (IODs). Among 110 subjects, there were 49 males and 61 females with a mean age of 11.39 ± 2.28 years. Compared with those in the isometropia group, AMP was lower and near stereopsis was higher in the LA group, and the distance and near heterophoria, PRA, AR, and near stereopsis were higher, and PRA, AMP, and gradient AC/A were lower in the HA group (all P < 0.05). Compared with those in the LA group, the near stereopsis, AR, and the near stereopsis were higher in the HA group, and the gradient AC/A was lower (all P < 0.05). However, no significant differences existed in the negative relative accommodation (P > 0.05). The distance and near heterophoria, AR, AMP, and near stereopsis were observed to be correlated with IODs, respectively (r = -0.259, p = 0.006; r = -0.201, p = 0.036; r = 0.306, p = 0.001; r = -0.315, p = 0.001; r = 0.535, p < 0.001). Our results suggested that with the increase of anisometropia, distance and near heterophoria, AR, AMP, and near stereopsis had a tendency to get worse in children with myopic anisometropia.

Changes in the anatomical and functional parameters of the eye when using glasses with Stellest™ lenses in children with progressive myopia

Relevance. Myopia is one of the most common refractive pathologies in the world. By 2050, according to WHO 2015, more than half of the world’s population will suffer from myopia, which will lead to the risk of developing pathologies associated with the progression of myopia, such as glaucoma, macular degeneration and retinal detachment. The use of various modern methods to control myopia can slow down the progression of myopia, which potentially reduces the risks of complications. Objective: to evaluate changes in the anatomical and functional parameters of the eye (clinical refraction, axial length, accommodation functions) in children with progressive myopia corrected with glasses with Stellest lenses in different age groups. Materials and methods. The study was conducted on the basis of the Eye Microsurgery Clinic of the Stavrapol State Medical University. Glasses with Stellest lenses were assigned to 80 children aged 8 to 16 years. The average age of the children was 11 ± 0.12 years. The children were divided into three age groups: 1st – primary school; 2nd -middle school; Group 3 – senior school. After the examination, the children were selected glasses with Stellest lenses. The average period of wearing glasses with Stellest lenses was 12 months. Clinical refraction, axial length and accommodation functions were evaluated during the observation. Results. The change in refraction depended on the age of the child. The greatest increase in refraction by 0.40 ± 0.02 D was observed in the younger age group, and the smallest (0.27 ± 0.02 D) in children of secondary school age. In the group of children of senior school age, the increase in refraction was +0.32 ± 0.03 D. The axial length of the eye in children of the primary school group after 12 months of wearing glasses with Stellest lenses signifi cantly increased by an average of 0.28 ± 0.03 mm. This axial growth of the eye correlates with an increase in myopic refraction in the same group of children. In the group of children of senior school age, the growth of PZO was 0.1 ± 0.04 mm. There was an increase in the accommodation reserve, the positive relative accommodation and the relative accommodation in all groups. Conclusions. The study showed that wearing glasses with Stellest lenses helps to reduce the rate of progression of myopia and increase the accommodative functions of the eye, which improves the adaptive capabilities and performance of the visual analyzer in all age groups of schoolchildren

Аnnual results of the use of spectacle lenses with embedded rings of high-spherical microlenses Stellest™ for the control of myopia

AIM: To evaluate the effect of continuous wearing of Stellest™ spectacle lenses on refractive dynamics, accommodation, and binocular interaction after 6 months and 1 year.&#x0D; MATERIAL AND METHODS: Children aged 8–13 years who had mild-to-moderate myopia were included. Stellest™ spectacle lenses were prescribed to 35 children with myopia (3.15±0.19 D on average). The control group consisted of 32 children with myopia (2.68±0.18 D on average) using single-vision correction. Refraction, axial length of the eye, accommodation, and binocular interaction were evaluated.&#x0D; RESULTS: After 1 year, the average increase in refraction in the Stellest™ group was 0.19±0.07 D. A decrease in the annual progression gradient (APG) was observed in 82.4% of cases and averaged 0.72±0.1 D. The axial length of the eye increased by an average of 0.08±0.02 mm. In the control group, after 1 year of observation, the average increase in refraction was 0.6±0.07 D. A decrease in APG was observed in 51.6% of the cases and averaged 0.26±0.12 D. The axial length of the eye increased by an average of 0.26±0.03 mm. After 1 year, the increase in refraction and growth of the axial length of the eye in the Stellest ™ group was less than that in the control group by 68.3% and 69.2%, respectively. In the Stellest™ group, positive relative accommodation (PRA) increased after 1 year by 1.06±0.14 D and that in the control group by 0.6±0.16 D. The difference was significant (p 0.02). No differences were found between the groups in terms of objective indicators of accommodation. The stabilization effect in Stellest™ spectacle lenses was the least pronounced with esophoria.&#x0D; CONCLUSION: The use of Stellest™ spectacle lenses slows down the progression of myopia in children and reduces APG by more than two times. A significant increase in PRA was found in children using Stellest™ spectacle lenses for 1 year compared with children using single-vision correction.

Слабость конвергенции как причина астенопии после лазерных рефракционных операций

Purpose. To evaluate the frequency of astenopia and effect of refractive surgery on muscle balance and accommodation in patients with convergence insufficiency (CI). Methods. This study prospectively evaluated 240 eyes (120 patients) with myopia. CI was found in 15 patients (12.5 %), 91 patients with normal binocular vision were included in control group. Accommodative amplitude and facility, positive and negative relative accommodation, binocular vision, near point of convergence (NPC), phoria measurement for near and distance, positive and negative fusion vergence, AC/A ratio were assessed, symptoms were measured by Convergence Symptom Survey (CISS) before, 1 month and 1 year after LASIK. Results. Asthenopia was found in 7.5 % of patients in 1 month after surgery. It was related with CI in 5 %. There was a statistically significant improvement of near exodeviation from 13.2±3.9 to 8.4±3.7 pd and of NPC from 12.2±2.7 to 8.3±2.3 сm which remained unchanged within 1 year. CISS score improved from 24.3±4.8 to 13.5±2.5 in 1 month after surgery and to 9.6±2.8 within 1 year. 1 patient had deterioration of exodeviation in 1 month. 6 patients needed in-office vergence/accommodative therapy after surgery. None of the patients in control group presented postoperative asthenopia, worsening in muscle balance and binocular vision. Conclusions. Laser refractive surgery does not cause asthenopia in patients with normal accommodation and vergence. CI is not a contraindication for refractive surgery, leading to a decrease in exodeviation. In cases of accurate fusion vergence lack, patients will experience asthenopia. In patients with CI it is necessary that positive fusion vergence exceed the exophoria by two times before surgery and overlap presbyopia addition which will be required in future. Key words: refractive surgery; asthenopia; convergence insufficiency.

Global risk factor analysis of myopia onset in children: A systematic review and meta-analysis.

This work aimed to comprehensively assess the risk factors affecting myopia in children to develop more effective prevention and treatment strategies. To this end, data from database were employed to assess the relationship between the incidence of myopia and its risk factors. We searched eight databases online in June 2022. Cohort studies were included that measured the connection between risk factors and myopia. Eligibility was not restricted by language. The Newcastle-Ottawa Scale (NOS) was used to measure the risk of bias and conducted GRADE evaluation to determine the certainty of evidence. Potential risk factors with positive or negative results were seen. Inplasy Registration: https://inplasy.com/inplasy-2022-4-0109/. Evidence that risk factors for myopia are mixed, comprising both positive (20) and null (17) findings. In 19 cohort studies on 3578 children, girls were more likely to develop myopia (RR: 1.28 [1.22-1.35]). Myopia can occur at any age, from early childhood to late adulthood. Children whose parents had myopia were more likely to develop myopia. Longer outdoor activities time (RR: 0.97 [0.95-0.98]) and less near-work time (RR: 1.05 [1.02-1.07]) appeared to be significantly decrease the incidence of myopia. Children with lower SE, longer AL, a lower magnitude of positive relative accommodation, worse presenting visual acuity, deeper anterior chamber, and thinner crystalline lens may be related to myopia onset. The burden of myopia in underprivileged countries is higher than in developed countries (RR: 5.28 [2.06-13.48]). The quality of evidence for the evaluated factors was moderate to low or very low. Genetic factors, environmental factors (such as excessive use of electronic products, and poor study habits) and lifestyle factors (such as lack of outdoor activities, poor nutrition, etc.) are the main risk factors for myopia in children. Myopia prevention strategies should be designed based on environmental factors, gender, parental myopia and eye indicators in order to explore a lifestyle that is more conducive to the eye health of children.

Orthokeratology and Visual Motor Training for Juvenile Myopia

This study aimed to explore the effect of orthokeratology (Ortho-K) combined with visual motor training in juvenile myopia. We included 156 myopia patients, which were randomly divided into the combined (visual motor training+Ortho-K) and Ortho-K (only) groups. Corneal morphological changes (horizontal keratometry [HK], vertical keratometry [VK], central corneal thickness [CCT], and corneal endothelial cell density), regulatory function (positive and negative relative accommodation [PRA, NRA], regulatory amplitude, and regulatory sensitivity), ocular axis, visual acuity (naked visual acuity, Diopter), tear film stability (BUT test and SIT test), intraocular pressure, and safety before and after treatment were compared between groups. Moreover, we performed a Spearman correlation analysis on the effects of initial age and diopter on axial growth. After treatment, HK, VK of cornea, and CCT levels significantly decreased in both groups while no significant changes were found in endothelial cell density. In the combined group, there was a higher improvement in PRA, accommodation amplitude, and accommodation sensitivity, which could delay ocular axis growth and improve naked eye vision and diopters. Meanwhile, a significant negative correlation was found between patients’ initial age and axial growth. Moreover, BUT and SIT recovery in the combined group were relatively better after wearing Ortho-K. In conclusion, Ortho-K combined with visual motor training could better correct the vision of juvenile myopia patients and delay ocular axis growth. In addition, the earlier the intervention, the better the effect.

Accommodative disorders in non-presbyopic subjects with type 1 diabetes without retinopathy: A comparative, cross-sectional study.

The purpose of this study was to assess accommodative function in non-presbyopic individuals diagnosed with type 1 diabetes (T1D) without any signs of retinopathy, to determine the existence of possible accommodative disorders related to this disease, and to determine the influence of T1D duration and glycosylated haemoglobin values on accommodative function. This comparative, cross-sectional study included 60 participants between 11 and 39 years old, 30 with T1D and 30 controls, with no previous eye surgery, ocular disease or medication that could affect the results of the visual examination. Amplitude of accommodation (AA), negative and positive relative accommodation (NRA and PRA), accommodative response (AR) and accommodative facility (AF) were assessed using the tests that showed the highest repeatability. Participants were classified based on normative values into 'insufficiency, excess or normal results', and a diagnosis of accommodative disorders (accommodative insufficiency, accommodative infacility and accommodative excess) was made. Participants with T1D had statistically significant lower AA and AF and higher NRA values than the controls. Furthermore, AA was significantly and inversely correlated with age and the duration of diabetes; however, AF and NRA were only correlated with disease duration. In the classification by accommodative variables, a higher percentage of 'insufficiency values' was observed in the T1D group (50%) than in the control group (6%; p < 0.001). In terms of accommodative disorders, accommodative infacility was the most prevalent (15%), followed by accommodative insufficiency (10%). Our findings indicate that T1D affects most accommodative parameters, with accommodative insufficiency being associated with this disease.

Binocular vision parameters and body mass index

Background: Abnormal body mass Index (BMI) can adversely affect binocular vision. We aimed to assess the presence of possible differences in binocular vision parameters among the four BMI categories.&#x0D; Methods: In this comparative cross-sectional study, we enrolled young adults and categorized them into underweight, normal weight, overweight, and obese groups based on their BMI. A complete orthoptic evaluation was performed to assess the mean values of binocular vision skills.&#x0D; Results: We recruited 120 participants with a mean (standard deviation) age of 21.30 (1.80) years with best-corrected distance and near visual acuities of 6/6 and N6, respectively. The frequency of exophoria &gt; 4 PD was high in the obese group. The frequency of binocular vision dysfunction was higher in the obese and underweight groups, with vergence dysfunction being the most common. The mean values for near negative fusional vergence (NFV), distance positive fusional vergence (PFV), negative relative accommodation, positive relative accommodation, monocular accommodation facility (AF), and monocular estimation method were comparable among the groups (all P &gt; 0.05). The obese group had significantly receded near point of convergence, and reduced accommodative convergence to accommodation ratio and binocular AF than the normal, overweight, and underweight groups (all P &lt; 0.05). The distance and near vergence facilities were significantly lower in the obese group than in the overweight and normal groups, and the distance vergence facility was significantly lower than in the underweight group (all P &lt; 0.05). The mean values of distance NFV and near PFV in the obese group were significantly lower compared to the normal and overweight groups, and the mean values of distance NFV were significantly lower compared to the underweight group (all P &lt; 0.05). The mean values of near PFV were significantly lower in the underweight group than in the overweight group (both P &lt; 0.05). Both the underweight and obese groups had a significantly lower amplitude of accommodation compared to the normal group (both P &lt; 0.05).&#x0D; Conclusions: The frequency of binocular vision dysfunction was higher in the obese and underweight groups. Most convergence and some accommodation parameters were adversely affected in individuals with obesity. Being underweight adversely affects certain binocular vision skills. Further studies are required to determine the relevance of BMI as a predictor of binocular vision abnormalities.

Changes in accommodation in children with hyperopic anisometropia and unilateral amblyopia after laser refractive surgery and pleoptic treatment

This study comparatively analyzes the state of accommodation in children with hyperopic anisometropia and amblyopia after femtosecond laser-assisted in situ keratomileusis (Femto-LASIK) combined with pleoptic treatment, and after conventional pleoptic treatment. The first group consisted of 30 children with medium and high hyperopia, high and medium amblyopia, and anisometropia greater than 3.0 diopters, who underwent Femto-LASIK in the amblyopic eye. The second group consisted of 28 children with similar local status, who were prescribed traditional correction and received conservative treatment. The follow-up period was 1.5 years. After 1.5 years, higher visual acuity (p<0.05) was achieved in the first group. A significant increase in the coefficient of accommodative response (CAR) was observed in the operated amblyopic eyes in group 1 - by 0.1±0.02 c.u. compared to the control group (p<0.05). In both groups there was an upwards trend for the coefficient of microfluctuations (CMF) in the amblyopic eye, but in the first group CMF increased more significantly (p<0.05). The objective accommodative response (OAR) and positive relative accommodation (PRA) of the amblyopic eye showed a double increase - by 1.0±0.23 and 0.9±0.38 diopters, respectively, at the end of treatment in the first group. The increase in similar indicators in the second group was insignificant (p<0.05). In children of the first group the difference in ciliary muscle thickness (CMT) of the amblyopic eye with disabled and enabled accommodation increased by 0.04±0.01 mm (p<0.05) in the anterior part of the ciliary muscle at the levels of CMTmax and CMT1. The data obtained in this study indicate the strong effect of refractive laser surgery in combination with pleoptic treatment on improving the visual acuity and the state of accommodation of the amblyopic and paired dominant eyes in children with hyperopic anisometropia, in contrast to conventional methods of treatment.

Transient change in the binocular visual function after femtosecond laser-assisted in situ keratomileusis for myopia patients.

The goal of this study was to compare the difference in binocular visual function for high and low-moderate myopes before and after femtosecond laser-assisted in situ keratomileusis (FS-LASIK). Thirty-three subjects (17 males and 16 females) were divided into two groups according to their preoperative refractive errors in spherical equivalent (SE): low-moderate myopia group (SE ≥-6.00 D) and high myopia group (SE <-6.00 D). The binocular visual function including accommodative amplitude (AA), accommodative facility (AF), positive and negative relative accommodation (PRA and NRA, respectively), horizontal phoria measurement, positive and negative fusion vergence, accommodative-convergence over accommodation (AC/A) ratio, and stereopsis were assessed with the best-corrected vision before patients received FS-LASIK and 7 and 30 days after the surgery. Repeated measures analysis of variance (ANOVA) was applied to study the change in binocular visual function. The AF values in both groups were significantly reduced after 7 days of FS-LASIK (baseline vs. day 7 (mean): high myopia group: 7.85 vs. 5.62 cpm, repeated ANOVA, P = 0.01; low-moderate myopia group: 5.95 vs. 4.40 cpm, repeated ANOVA, P = 0.04). This change returned to the baseline level 30 days after the operation. In addition, the horizontal phoria values in both groups were significantly reduced for both distant (P = 0.019 and P = 0.001, respectively) and near (P = 0.003 and P = 0.049, respectively) 7 days after the operation, but they rebound to preoperative state after 30 days. A transient change in binocular visual function was noticed after 7 days of FS-LASIK operation, which could cause symptoms of asthenopia. Our data showed all the binocular visual functions returned to baseline level after 30 days of operation.

Возможности коррекции оксидативного стресса в офтальмологической практике

A total of 238 patients presenting with the diagnosis of myopia or habitually excessive accommodation strain were examined and treated. It was shown that the introduction of antioxidative drugs in the combined treatment of the above disorders normalized the antioxidant properties of blood plasma and improved the blood supply to the eye which as a result increased the positive relative accommodation. The composite antioxidant drugs proved to exhibit the especially high therapeutic efficacy. Given the numerous reports of the successful use of this group of drugs in various ophthalmic pathologies, the great potential of this therapy area makes it expedient to search for new substances with antioxidant activity, as well as the best ways to administer them. Key words: ophthalmic pathology, oxidative stress, antioxidants, irrigation therapy

Correlation between Eye Movements and Asthenopia: A Prospective Observational Study.

Purpose: To analyze the correlation between eye movements and asthenopia so as to explore the possibility of using eye-tracking techniques for objective assessment of asthenopia. Methods: This prospective observational study used the computer visual syndrome questionnaire to assess the severity of asthenopia in 93 enrolled college students (age 20−30) who complained about asthenopia. Binocular accommodation and eye movements during the reading task were also examined. The correlations between questionnaire score and accommodation examination results and eye movement parameters were analyzed. Differences in eye movement parameters between the first and last reading paragraphs were compared. The trends in eye movement changes over time were observed. Results: About 81.7% of the subjects suffered from computer visual syndrome. Computer visual syndrome questionnaire total score was positively correlated with positive relative accommodation (p < 0.05). In the first reading paragraph, double vision was positively correlated with unknown saccades (all p < 0.05). Difficulty focusing at close range was positively correlated with total fixation duration, total visit duration, and reading speed (all p < 0.05). Feeling that sight was worsening was positively correlated with regressive saccades (p < 0.05). However, visual impairment symptoms were not significantly correlated with any accommodative function. In a total 20 min reading, significantly reduced eye movement parameters were: total fixation duration, fixation count, total visit duration, visit count, fixation duration mean, and reading speed (all p < 0.01). The eye movement parameters that were significantly increased were: visit duration mean and unknown saccades (all p < 0.001). Conclusion: Eye tracking could be used as an effective assessment for asthenopia. Among the various eye movement parameters, a decrease in fixation duration and counts may be one of the potential indicators related to asthenopia.

Accommodation Response Variations in University Students under High Demand for Near-Vision Activity.

The objective of this study was to investigate accommodation changes and visual discomfort in a university student population after a period of high demand for near-vision activity. A total of 50 university students aged between 20 and 22 years were recruited. The tests performed involved positive relative accommodation (PRA), negative relative accommodation (NRA), accommodation amplitude (AA), and monocular and binocular accommodative facility (MAF and BAF). Visual discomfort was measured on a scale involving a visual discomfort questionnaire (VDQ). All accommodative variables underwent changes during the exam period; specifically, regarding NRA and PRA, 30.4% and 15.1% of the studied population, respectively, appeared to be below average. Moreover, 42.3% of the population exhibited values below average in the second measure of AA. On the other hand, a small percentage of the population was below average in MAF and BAF measurements: 3% in the monocular right eye test, 6% in the left eye test, and 9.1% in the binocular facility test. Finally, the VDQ score did not reveal a statistically significant difference between the two measurements. Prolonged near-distance work, such as a university exams period, changed all accommodation systems (amplitude of accommodation, relative accommodation, and accommodation facility). These changes influence an accommodation excess that results in blurred vision, headache, and problems with focusing.

Clinical features and treatment of near-work-related acquired esotropia.

To investigate the characteristics of near-work-related esotropia and the clinical efficacy of botulinum toxin type A (BTXA) injection therapy on it. A total of 107 patients aged 15-57y with near-work-related esotropia were taken as the BTXA-treated group, and 30 other peers without near-work-related esotropia were included in the control group. All participants were refractive corrected to analyse the clinical characteristics of near-work-related esotropia. All subjects were examined including Worth4 spot examination, stereoscopic vision, strabismus angle, accommodative convergence to accommodation ratio (AC/A), far and near positive and negative convergence, positive and negative fusion range, positive and negative relative accommodation. Clinical efficacy was evaluated at a period of 10mo follow-up. The distant and near stereopsis were found in 84.9% and 77.5% of patients in the BTXA-treated group, respectively. In the control group, all patients had distant and near stereopsis. The incidence of taking off one's glasses to see close objects was significantly higher in the BTXA-treated group than in the control group (P<0.05). The BTXA-treated group showed a smaller range of in-fusion (9.84±5.72)° than the control group (22.04±8.71)° (P<0.05). The near esotropia angle of the BTXA-treated group (17.08±11.98)Δ was significantly smaller than the distant esotropia angle (19.07±11.68)Δ (P<0.05). Ten months after injection, the diplopia and esotropia of most patients underwent improvements after treatment (P<0.05). This study reveals that the accommodation function and the habit of near work without wearing spectacles are associated with near-work-related esotropia, while the length of time for near work and the onset time are independent of near-work-related esotropia. Additionally, BTXA injection therapy plays a vital role in relieving diplopia and restoring eye position.

Low-intensity red-light therapy in slowing myopic progression and the rebound effect after its cessation in Chinese children: a randomized controlled trial.

To investigate the effect of low-intensity red-light (LRL) therapy on myopic control and the response after its cessation. A prospective clinical trial. One hundred two children aged 6 to 13 with myopia were included in the LRL group (n = 51) and the single-focus spectacles (SFS) group (n = 51). In LRL group, subjects wore SFS and received LRL therapy provided by a laser device that emitted red-light of 635nm and power of 0.35 ± 0.02 mW. One year after the control trial, LRL therapy was stopped for 3months. The outcomes mainly included axial length (AL), spherical equivalent refraction (SER), subfoveal choroidal thickness (SFCT), and accommodative function. After 12months of therapy, 46 children in the LRL group and 40 children in the SFS group completed the trial. AL elongation and myopic progression were 0.01mm (95%CI: - 0.05 to 0.07mm) and 0.05 D (95%CI: - 0 .08 to 0.19 D) in the LRL group, which were less than 0.39mm (95%CI: 0.33 to 0.45mm) and - 0.64 D (95%CI: - 0.78 to - 0.51 D) in the SFS group (p < 0.05). The change of SFCT in the LRL group was greater than that in the SFS group (p < 0.05). Accommodative response and positive relative accommodation in the LRL group were more negative than those in the SFS group (p < 0.05). Forty-two subjects completed the observation of LRL cessation, AL and SER increased by 0.16mm (95%CI: 0.11 to 0.22mm) and - 0.20 D (95%CI: - 0.26 to - 0.14 D) during the cessation (p < 0.05), and SFCT returned to baseline (p > 0.05). LRL is an effective measure for preventing and controlling myopia, and it may also have the ability to improve the accommodative function. There may be a slight myopic rebound after its cessation. The effect of long-term LRL therapy needs to be further explored. Chinese Clinical Trial Registry: Chinese Clinical Trails registry: ChiCTR2100045250. Registered 9 April 2021; retrospectively registered. http://www.chictr.org.cn/showproj.aspx?proj=124250.

Measures of accommodative function in secondary school year 9 and year 13: a 4-year longitudinal study.

PurposeTo characterize accommodative function in secondary school children in year 9 and year 13 and assess the possible relationship between daily working conditions (number of near work hours and distances) and accommodation variables related to accommodative excess.MethodsThis was a prospective study. Participants were 43 subjects who were first examined in year 9 and then again when they were in year 13. The accommodation variables measured in each session were as follows: accommodation amplitude (AA), accommodative response (AR), monocular and binocular accommodation flexibility (MAF and BAF), negative relative accommodation (NRA), and positive relative accommodation (PRA). Other data recorded were the number of hours spent working at near vision tasks and the distances used for these tasks. Participants were classified as those with accommodation variables within the normal range (NA) and those with variables suggesting accommodative excess (AE).ResultsSeveral accommodative function variables were below normative values in both year 9 and year 13. The number of subjects classified as having AE went from 27.9% in year 9 to 58.1% in year 13 according to AR (p < 0.005) and from 23.3 to 46.5% according to MAF (p = 0.024). More near work was reported in year 13 (44.6 h/week) than year 9 (32.7 h/week) (p < 0.001). It emerged that subjects in year 13 spent more hours working at near if they had AE than if they were assigned to the NA group. No differences were detected in near work distances used by subjects in the NA and AE groups in both years.ConclusionsIn both school years, values outside the norm were detected in several accommodative function measures. Also, devoting more hours to near work was linked to a greater extent of accommodative excess. We would therefore recommend regular accommodative function assessment in secondary school children.

Development and validation of a novel nomogram for predicting the occurrence of myopia in schoolchildren: A prospective cohort study

Myopia is a major public health issue and occurs at young ages. Apart from its high prevalence, myopia results in high costs and irreversible blinding diseases. Accurate prediction of the risk of myopia onset is crucial for its precise prevention. We aimed to develop and validate an effective nomogram for predicting myopia onset in schoolchildren. School-based prospective cohort study. A total of 1073 schoolchildren were enrolled from November 2014 to May 2019 in China, and were divided into the training and validation cohorts. Myopia was defined as a spherical equivalent refraction (SER) ≤-0.5 diopters. Predictors of myopia were determined through the least absolute shrinkage and selection operator regression and multivariable Cox proportional hazard model based on the training cohort. The predictive performance of the nomogram was validated internally through time-dependent receiver operating characteristic (ROC) curves, calibration plot, decision curve analysis, and Kaplan-Meier curves. Independent predictors at baseline including gender, SER, axial length, corneal refractive power, and positive relative accommodation were included in the nomogram prediction model. This nomogram demonstrated excellent calibration, clinical net benefit, and discrimination, with all the area under the ROC curves (AUCs) between 0.74 and 0.86 in the training and validation cohorts. The Kaplan-Meier curves showed that 3 distinct risk groups stratified through X-tile analysis were well discriminated and robust among subgroups. The Harrell's C-index and net reclassification improvement demonstrated that the nomogram substantially improved compared with previous models. An online myopia risk calculator was generated for better individual prediction. The nomogram provides accurate and individual prediction of myopia onset in schoolchildren. External validation is needed to verify the generalizability of this nomogram.