Binocular Vision Anomalies Research Articles

Study of prevalence of non-strabismic binocular vision anomalies in a tertiary centre: An important but often forgotten cause of ophthalmic headache

To study the presence of non strabismic binocular vision anomalies in young patients presenting with headache. A prospective, non-interventional study of 110 patients was conducted for a period of one year in our tertiary eye care institute after obtaining informed consent and taking into consideration the inclusion and exclusion criteria. Patients presenting with asthenopic symptoms were subjected to thorough ophthalmic examination. After excluding refractive errors, patients were further subjected to detailed orthoptic evaluation (including accommodation and convergence assessment). Other non-ocular causes of headache were ruled out by appropriate referrals. Out of 110 patients, 33% were found to have accommodative insufficiency, 14% were having convergence insufficiency and 4% showed both accommodative and convergence insufficiency. 49% patients showed no extraocular muscle imbalance and were referred to relevant specialities for further evaluation. It is important to perform a thorough evaluation of patients presenting with headache for the presence of non strabismic binocular vision anomalies after ruling out other ophthalmic causes.

Age-Matched Comparative Analysis of Binocular Vision Anomalies among Children with Dyslexia in Northern Nigeria.

Background: Dyslexia, a neurodevelopmental disorder affecting reading skills, poses significant challenges to children's academic performance and quality of life. Despite its rising prevalence and adverse effects, understanding of its relationship with vision anomalies remains limited, particularly in low-resource settings like Nigeria. This study aims to assess the prevalence of binocular vision anomalies (BVAs) among children with and without dyslexia in Kano, Nigeria. Methods: This is a hospital-based, cross-sectional, matched-paired, controlled study conducted at the Aminu Kano Teaching Hospital (AKTH) Eye Clinic in Northern Nigeria. The study included school children who visited the AKTH Eye Clinic from January 2018 to December 2022. Visual acuity tests, external eye examinations and accommodative, binocular vision and oculomotor skills tests were conducted. Descriptive statistics, independent t-tests, Mann-Whitney U tests and Fisher's exact tests were conducted, with a significance level set at p < 0.05. Results: Forty-four children aged 12 ± 2 years participated. Children with dyslexia reported higher rates of visual symptoms than those without dyslexia, Blurring vision, visual distortion and eye strain were the most prevalent (p < 0.05) BV symptoms. Accommodative insufficiency), was the most common visual abnormality, and was significantly higher in children with dyslexia than those without dyslexia (45.5% vs. 18.2%). However, other visual anomalies showed no significant difference between groups. There was a high prevalence of binocular vision anomalies in both groups. Binocular test findings showed dyslexic children had significantly lower distance positive fusional vergence recovery values (p = 0.005). All cases of convergence insufficiency alone were found in the non-dyslexic group. Conclusions: The study found that children with dyslexia residing in Northern Nigeria demonstrated higher rates of visual symptoms, more accommodative insufficiency and lower distance positive fusional vergence recovery values compared to their non-dyslexic counterparts.

Prevalence of non-strabismic binocular vision anomalies (NSBVA) among university students of North India

Prevalence of non-strabismic binocular vision anomalies (NSBVA) among university students of North India

Frequency of Non-strabismic Binocular Vision Anomalies among Optometrists in a Tertiary Eye Care Center in Southern India.

Lifestyle in the modern era has drastically changed across the globe, and the healthcare profession was no exception. The increased time spent in the virtual space for various purposes, including online classes and webinars, is hypothesized to increase the risk of vision-related disorders such as asthenopia, dry eyes, and visual fatigue. The purpose of this study was to evaluate fusional vergence and ocular accommodation among optometry professionals in a tertiary eye care center during the immediate post-coronavirus disease 2019 (post-COVID-19) lockdown period. Optometrists posted in the general out-patient department, specialty clinics, and the ocular diagnostics department were included in the study. A total of 65 optometrists were included in the study. All optometrists underwent a comprehensive binocular vision assessment. Convergence Insufficiency Symptom Survey questionnaires were administered to all optometrists at the beginning of the assessment. Out of 65 optometrists, 48 (73.8%) were women. The mean (standard deviation) age of the participants was 24 (3) years. Eleven (16.9%) optometrists had normal binocular vision parameters, and the rest 54 (83.1%) had non-strabismic binocular vision anomalies. Reduced accommodative facility and convergence insufficiency were seen among 43 (66.2%) optometrists, whereas 30 (46.2%) had reduced accommodative facility alone. Twelve (18.5%) participants were symptomatic as per the convergence insufficiency symptom survey. This study highlights the fact that a large proportion of optometrists have undetected non-strabismic binocular vision anomalies in a tertiary eye care center. It is important for eye care professionals to undergo regular binocular vision assessments in association with ophthalmic examinations and relevant management. This will ensure that these dysfunctions do not impede work productivity and overall quality of life.

Retracted: Evaluation of a Novel Quality of Life Scale for Schoolchildren with Nonstrabismic Binocular Vision Anomalies.

[This retracts the article DOI: 10.1155/2020/4723402.].

Kinematic Assessment of Fine Motor Skills in Children: Comparison of a Kinematic Approach and a Standardized Test.

Deficits in fine motor skills have been reported in some children with neurodevelopmental disorders such as amblyopia or strabismus. Therefore, monitoring the development of motor skills and any potential improvement due to therapy is an important clinical goal. The aim of this study was to test the feasibility of performing a kinematic assessment within an optometric setting using inexpensive, portable, off-the-shelf equipment. The study also assessed whether kinematic data could enhance the information provided by a routine motor function screening test (the Movement Assessment Battery for Children, MABC). Using the MABC-2, upper limb dexterity was measured in a cohort of 47 typically developing children (7-15 years old), and the Leap motion capture system was used to record hand kinematics while children performed a bead-threading task. Two children with a history of amblyopia were also tested to explore the utility of a kinematic assessment in a clinical population. For the typically developing children, visual acuity and stereoacuity were within the normal range; however, the average standardized MABC-2 scores were lower than published norms. Comparing MABC-2 and kinematic measures in the two children with amblyopia revealed that both assessments provide convergent results and revealed deficits in fine motor control. In conclusion, kinematic assessment can augment standardized tests of fine motor skills in an optometric setting and may be useful for measuring visuomotor function and monitoring treatment outcomes in children with binocular vision anomalies.

Comparison of Near Point of Accommodation and Near Point of Convergence with Positive Fusional Vergence among Young Adults, Bengaluru

Background: When encountered with mass screening and increased walk-in patients in outpatient departments (OPD), evaluating complete binocular vision assessment becomes time-consuming. Consequently, there is a need to streamline the testing process. This study also aims to explore if there are any correlations between Near Point of Accommodation (NPA) and Near Point of Convergence (NPC) with Positive Fusional Vergence (PFV). Methodology: A retrospective study was carried out at Sankara Eye Hospital in Bangalore. Data from patients aged 18 to 35, who underwent binocular vision assessment between 2016 and 2020, were included. Out of 101,896 patients who visited the hospital during this period, 3,449 attended the vision therapy clinic. Among them, 1708 patients met the criteria for inclusion, while 1,741 were excluded. Results: Out of 1708 subjects, 759 are females and 949 are males. The relationship between Near Point of Accommodation (NPA), Near Point of Convergence (NPC), and Positive Fusional Vergence (PFV) blur and break values were analysed. A positive correlation was observed between NPA and PFV blur (Spearman's rho = 0.069, p=0.004) and a negative correlation between NPC and PFV break (Spearman's rho = -0.370, p&lt;0.001). There was a significant difference between NPA and PFV blur, as well as NPC and PFV break (p=0.000), emphasizing the importance of incorporating all three tests in a binocular vision assessment. Conclusion: These results emphasize the necessity for complete binocular vision assessment to effectively diagnose and manage binocular vision anomalies. By accounting for the various parameters involved in this investigation, clinicians can enhance the precision and quality of their assessments and plan for appropriate treatment strategies for patients with binocular vision anomalies.

Diagnosis of non‐strabismic binocular vision anomalies ‐ why are there so many different approaches?

Aims/Purpose: To review and contrast the main approaches for diagnosing and managing non‐strabismic binocular vision anomalies (BVA), including decompensated heterophoria, binocular instability, accommodative anomalies.Methods: A literature search was undertaken to determine the main methods of diagnosing and correcting/treating BVA. Findings from leading textbooks were compared with research literature. The literature was filtered by country and by profession to investigate factors that may contribute to diversity of approaches.Results: The literature searches reveal marked variation in the methods recommended for diagnosing BVA. There is agreement concerning the interventions available (refractive correction, prisms, eye exercises, surgery). However, there are diverse opinions concerning the criteria for determining when treatment is required. For refractive correction or prisms, the evidence suggests that different methods used for determining the correction required will lead to different prescriptions. To some extent, the variation can be attributable to national differences. However, even within some countries, very diverse diagnostic criteria and prescribing philosophies are evident. A wide variation sometimes is present within as well as between the different eyecare professions.Conclusions: Research with standardized patients indicates, clinical practice is likely to be even more varied than the review indicates. The wide variation means that even within a country/profession, a patient may consult two practitioners and receive different diagnoses, or dissimilar interventions. One reason for the variation is likely to be the historical influence of prominent clinicians/teachers. Evidence‐based scrutiny should be applied to old methods as well as new. Research is required that compares different philosophies for diagnosis and prescribing.

The Impact on Vergence Parameters After Smartphone Gaming.

To evaluate the impact of smartphone gaming on the vergence system of the eye. A 5-month (from March 2023 to August 2023) comparative and experimental research was conducted. Eighty-two participants with a mean age of 21.98 ± 2.26 years were present in the study. Prior to assessing accommodation and vergence system characteristics, participants underwent a comprehensive eye examination. The participants were asked to play a shooting game on a smartphone for 30 minutes at a 40 cm distance. Measurements of the vergence parameters were taken before and after the activity and afterwards were compared. Non-parametric tests were used to compare pre- and post-task measurements. The Wilcoxon signed-rank test was used to compare the variables: Negative fusional vergence (NFV), Positive fusional vergence (PFV), Near point of convergence (NPC), and Vergence Facility (VF), with the alpha error set at 5%. The mean age of the participants was 21.98 ± 2.26 years. Post-task, the vergence parameters: NPC (p < 0.001), NFV for near distance (p < 0.001), PFV for near distance (p < 0.001), and VF (p < 0.001) showed significant decrease in vergence parameters. The study shows smartphone gaming for 30 minutes affects the vergence system, leading to binocular vision anomalies in young individuals.

The effect of action and casual video games on visual reaction time and accommodation in non-gamers

Aim: To understand the effect of video games on non-gamers’ visual reaction time (VRT) and Accommodation. Methodology: A cross sectional study was conducted to evaluate the effect of video games on VRT and Accommodation in non-gamers. Subjects between the age of 18-28 years with BCVA 0.0 LogMAR; 0.63M were enrolled in this study. A written consent was obtained. Subjects having binocular vision anomalies, systemic diseases, learning disabilities, and dry eyes were excluded from the study. All subjects underwent a comprehensive eye exam. In addition, VRT and Accommodation were measured pre and post exposure to video games. VRT was assessed with PEBL (Psychology Experiment Building Language) and WAM open field autorefractor was used to measure Accommodation. Result: 17 subjects (15 females and 2 males) participated in the study with the mean age of 21 ± 1.70 years. In the action video game group, mean VRT decreased significantly from 362.56±31.68ms to 348.75±31.35ms post video game exposure (p&lt;0.05). The mean VRT in casual video game group pre video game exposure was 358±29.56ms and post was 353.89±26.8ms (p&gt;0.05). The accommodative response exhibits a significant change, with pre-exposure mean of -0.98D and post exposure mean of -1.20D (p&lt;0.05). Conclusion: Action video games were found to enhance VRT significantly, making them a potential tool for activities requiring rapid reactions. While casual video games also improved VRT, the changes were not statistically significant. Moreover, both types of video games had a significant impact on accommodative responses, which could be clinically relevant for individuals with accommodation related issues.

Effectiveness of Clinic-Based Vision Therapy for Non-Strabismic Binocular Vision Anomalies (NSBVA) Among Adults

Background: To assess the effectiveness of clinic-based vision therapy in adults with non-strabismic binocular vision anomalies. Methods: This retrospective study was conducted between January 2018 and December 2021 at a tertiary eye care center in Southern India. Elec-tronic medical records of adults aged 30 years and above diagnosed with non-strabismic binocular vision anomalies, and who underwent a mini-mum of five sessions of clinic-based vision therapy (VT), were reviewed. Clinical parameters of vergence and accommodation were analyzed pre and post-therapy. Results: A total of 44 participants meeting the inclusion criteria were included in the study, with a mean (SD) age of 36 (±6) years. The partic-ipants were categorized into two groups based on the completion of either five sessions (Group A) or ten sessions (Group B) of vision therapy (VT). The overall median (IQR) for near phoria was -4 (-8 to 0) PD, the near point of convergence break point was 8 (4 to 12) cm, fusional conver-gence amplitude for near was 25 (14 to 30) PD, and binocular accommo-dative facility and amplitude were 3 (0 to 6) cpm and 9 (7 to 10) D, respectively. Conclusion: Clinic-based vision therapy is efficacious in managing non-strabismic binocular vision anomalies in adult.

Accuracy and intrasession variability of noncycloplegic autorefraction of school-aged children and adolescents.

The aims of the study were (1)to compare the accuracy and intrasession variability of noncycloplegic autorefraction (AR) obtained by a photorefractor and conventional and open-field autorefractors and (2)to evaluate the impact of accommodative and binocular vision anomalies on the accuracy of autorefraction. Twenty-nine children and adolescents aged 8-18years were examined. All instruments gave more myopic results than subjective refraction (SR). Mean differences between the SR and the AR were +0.52/-0.25×96∘ for the photorefractor, +0.63/-0.31×93∘ for the conventional autorefractor, and +0.19/-0.26×94∘ for the open-field instrument. The photorefractor appeared to be the most repeatable. The impact of the examined vision anomalies on the accuracy of autorefraction was not statistically significant.

Clinical features of Sudanese patients presenting with binocular vision anomalies: A hospital-based study.

Binocular vision anomalies are major causes of asthenopia symptoms, particularly among the younger population. This study aimed to report the clinical characteristics of Sudanese patients with binocular disorders who attended the orthoptic clinic at Al-Neelain Eye Hospital. In this retrospective hospital-based study, we analyzed data from 304 patients with binocular vision anomalies who visited the orthoptic clinic between October 2020 and June 2021. We collected information on demographics, symptoms, and eye tests such as visual acuity (VA), refractive error (RE), angle of deviation, and the assessment of fusional vergence. Our findings indicated that exophoria was the most common binocular vision anomaly, affecting 79.8% of males and 71.6% of females (p=0.731). Children between 6 and 17 years old showed the highest prevalence of exophoria (75.9%) (p=0.0001). Among patients with exophoria, 100% reported itching associated with tearing during fixation, while 89.5% experienced difficulty in fixation. Refractive error varied by the type of binocular vision disorders (p=0.0001), with higher hyperopia observed in cases of unilateral esotropia and alternate esotropia (+3.571±1.238 D and +3.023±1.553 D, respectively). Positive fusional vergence (PFV) differed by types of binocular vision disorders (p=0.0001) with high PFV in esophoria (18.063±6.848∆) compared to low PFV in exophoria (12.80±5.313∆). The most common types of exophoria were convergence weakness exophoria (45.39%), followed by convergence insufficiency (20.39%). The study concluded that exophoria was the most common binocular vision anomaly among Sudanese patients, with convergence weakness and convergence insufficiency being the predominant anomalies. Headache was commonly prevalent among patients with binocular vision problems. Higher hyperopia was found in esodeviation, while low PFV was associated with exodeviation.

The diagnostic accuracy of the IFLIP system for binocular visual function anomalies assessment.

This study aimed to evaluate the diagnostic accuracy of the intelligent flipper (IFLIP) system in identifying binocular vision anomalies. This study comprised 70 participants aged 18 to 22. Participants underwent comprehensive eye assessments, including measurement of visual acuity, refraction, far and near cover test, stereopsis, and worth four dot test. The manual accommodation amplitude and facility, as well as the IFLIP system test, were also evaluated. The correlation between the indices of the IFLIP and manual accommodation tests was analyzed using multiple regression models, and the diagnostic ability of the IFLIP was characterized using Receiver Operating Curve (ROC) analysis. The significance level was 0.05. The mean age of the 70 participants was 20.03±0.78 years. The mean manual and IFLIP accommodation facilities were 12.00±3.70 cycle per minute (CPM) and 10.01±2.77 CPM, respectively. No correlation was found between the indices of the IFLIP system and manual accommodative amplitude. However, the regression model showed that the contraction/relaxation ratio of the IFLIP system was positively correlated to the manual accommodation facility, and the average contraction time was negatively correlated with the manual accommodation facility. The ROC analysis proposed a cut-off of 10.15 CPM monocularly for the IFLIP accommodation facility assessment. This study indicated that the parameters obtained by the IFLIP system and the manual accommodation facility were comparable, and the IFLIP system had good sensitivity and specificity in the assessment of the accommodation facility, thus may serve as a promising tool for screening and diagnosis of binocular visual function anomalies in clinical and community settings.

A comparative study on slow down progression of myopia using atropine 0.01% in children

The aim of the study was to determine the efficacy of lower concentration of Atropine 0.01% in promoting unaided visual acuity and slowing down the progression of myopia in children over 6 months. It was a hospital-based comparative study in the outpatient department of Ophthalmology, AL, LT, ACD, PPD, SPD, PGP were taken by Lenstar and Lensometer.The Comparative study was performed on 60 children from 9 to 15 years age group with initial myopic spherical equivalence from 0.5 to 6.00 D. The children were screened for visual acuity for distance and near using Snellen’s chart. Cycloplegic Refraction was done to know the presence of Refractive Errors. This study was approved by IRB Ethical Committee. (SCAHS/IRB/2022/JULY/420).The inclusion criteria include Ammetropic children with no binocular vision anomalies and no history of ocular disease. The primary outcome was the rate of myopic progression after 6 months. The participants were instructed to use Atropine 0.01% eye drops during night times for 6 months and the rate of myopic progression and the spherical equivalence, axial length, lens thickness, anterior chamber depth, photopic and scotopic pupil diameter were re-assessed to compare the progression of myopia in the children. Sixty children enrolled for six months study in which the mean progression of myopia was found to be within 0.27D and axial elongation shows 0.23 mm changes respectively, whereas there were no significant changes in the anterior chamber depth, lens thickness, photopic and scotopic pupil diameter before and after assessment in children. Spherical power, Axial Length, Anterior Chamber Depth, Lens Thickness, Photopic Pupil Diameter and Scotopic Pupil Diameter all showed significant progression from pre to post stages, with the average post reading deviating by 0.25 from the normal limits.

Evaluation of Visual Skills Between Cricket Players and Sedentary Individuals

Aim: This study aims to evaluate the visual skills between cricket players and sedentary individuals of the same age group and to determine that visual skills are beneficial for both competitive sports performance and daily task activities. Settings and Design: It was a sports vision-based comparative study conducted in the outpatient department of ophthalmology for preliminary ocular examination as well as in the cricket ground for sports vision-based tests. Methods and materials: This study carries 200 subjects out of which 100 cricket players and 100 sedentary individuals (i.e individuals who are not involved in any sports activities) participated between the age group of 18 to 26. Participants underwent preliminary ocular examinations in which all those ocular diseases and binocular vision anomalies are excluded. All subjects were undergone the following sports vision test: stereopsis was measured by Randot stereo acuity chart, accommodative facility with +/- 2.00 flippers, saccadic eye movement was measured by Lang fixation stick and eye-hand coordination was recorded by Alternate hand wall toss test. Result: The cricket players exhibited better accommodative facility (p=0.05) saccadic eye movements (p=0.03) and better eye-hand coordination (p=0.01) stereopsis was good in sedentary individuals (p=0.06) confirming that basic visual skills were high in sedentary individuals. Conclusion: These findings evidence that cricket players exhibit better performance in more visual skills in comparison with a group of individuals without sporting background, suggesting an improvement in visual skills due to routine systematic activity in sports as well as daily tasks.

TFOS Lifestyle: Impact of the digital environment on the ocular surface

Eye strain when performing tasks reliant on a digital environment can cause discomfort, affecting productivity and quality of life. Digital eye strain (the preferred terminology) was defined as “the development or exacerbation of recurrent ocular symptoms and/or signs related specifically to digital device screen viewing”. Digital eye strain prevalence of up to 97% has been reported, due to no previously agreed definition/diagnostic criteria and limitations of current questionnaires which fail to differentiate such symptoms from those arising from non-digital tasks. Objective signs such as blink rate or critical flicker frequency changes are not ‘diagnostic’ of digital eye strain nor validated as sensitive. The mechanisms attributed to ocular surface disease exacerbation are mainly reduced blink rate and completeness, partial/uncorrected refractive error and/or underlying binocular vision anomalies, together with the cognitive demand of the task and differences in position, size, brightness and glare compared to an equivalent non-digital task. In general, interventions are not well established; patients experiencing digital eye strain should be provided with a full refractive correction for the appropriate working distances. Improving blinking, optimizing the work environment and encouraging regular breaks may help. Based on current, best evidence, blue-light blocking interventions do not appear to be an effective management strategy. More and larger clinical trials are needed to assess artificial tear effectiveness for relieving digital eye strain, particularly comparing different constituents; a systematic review within the report identified use of secretagogues and warm compress/humidity goggles/ambient humidifiers as promising strategies, along with nutritional supplementation (such as omega-3 fatty acid supplementation and berry extracts).

Nexus of ocular motility and dry eye.

To evaluate the effectiveness of vision therapy (VT) in patients with chronic presumed refractory dry eye disease (DED) and concurrent nonstrabismic binocular vision anomalies (NSBVAs). To propose an algorithmic approach to manage patients with refractory DED. Thirty-two patients with chronic (>1 year) presumed refractory DED and NSBVA were prospectively evaluated. The baseline dry eye evaluation and comprehensive orthoptic evaluation were done. VT was administered by a trained orthoptist for 2 weeks. The binocular vision (BV) parameters and percentage subjective improvement were assessed after the VT. On evaluation, 12 patients (37.5%) had both DED and NSBVA, and 20 patients (62.5%) had only NSBVA. Twenty-nine patients (90.62%) showed significant improvement in BV parameters following VT. Binocular near point of accommodation (median, range) improved from 17 (8-40) to 12 (5-26) mm (P value < 0.0001), and near point of convergence (median, range) improved from 6 (3-33) to 6 (5-14) (P value 0.004) with VT. Thirty-one patients (96.87%) reported symptomatic improvement after VT, and 62.5% of these showed more than 50% improvement in symptoms. The present study confirms the beneficial role of VT in the treatment of patients with DED with concurrent NSBVA. It is essential to diagnose and treat NSBVA in patients with DED to ensure complete relief of symptoms and patient satisfaction. As there is a significant overlap between symptoms of dry eye disease and that of NSBVA, a complete orthoptic evaluation is recommended in all patients presenting with refractory dry eye disease related symptoms.

Applications and implications for extended reality to improve binocular vision and stereopsis.

Extended reality (XR) devices, including virtual reality (VR), augmented reality (AR), and mixed reality (MR) devices, are immersive technologies that can swap or merge the natural environment with virtual content (e.g., videogames, movies, or other content). Although these devices are widely used for playing videogames and other applications, they have one distinct feature that makes them potentially very useful for the measurement and treatment of binocular vision anomalies-they can deliver different content to the two eyes simultaneously. Indeed, horizontally shifting the images in the two eyes (thereby creating binocular disparity) can provide the user with a compelling percept of depth through stereopsis. Because these devices are stereoscopic, they can also be used as high-tech synoptophores, in which the images to the two eyes differ in contrast, luminance, size, position, and content for measuring and treating binocular anomalies. The inclusion of eye tracking in VR adds an additional dimension to its utility in measuring and treating binocular vision anomalies, as well as other conditions. This paper describes the essential requirements for testing and treating binocular anomalies and reviews current studies in which XR devices have been used to measure and treat binocular vision anomalies.

CORRELATION BETWEEN MIGRAINE &amp; REFRACTIVE ERRORS IN YOUNG POPULATION

One of the major public health problems is headache. To evaluate refractive errors we can compare subjects with migraine headache with healthy subjects. Retinoscopy and subjective refraction can be done to find out anisometropia and type of refractive errors; myopia, hypermetropia and astigmatism. The incidences of sporadic headache, chronic primary headache are the causes for chief complaints from patients. Obviously the young adults contribute a vital role in economic and social aspects of the society, so headaches causes less work efficiency and personal too. Acute glaucoma, optic neuritis has been found to be responsible to be linked with headache. It was also reported the higher prevalence of headache in subjects with binocular vision anomalies and uncorrected refractive errors, not all the studies consistent with this theory. The criteria for the migraine connected with refractive errors include: (1) uncorrected refractive errors or wrongly corrected refractive errors; (2) mild pain in eyes and frontal lobe; (3) pain that is relieved by resting but get worse by doing visual tasks at the distance or angle for a long time when visual acuity is impaired. Purpose: To compare the prevalence of refractive errors in the young adults with headaches