Prevalence of heterophoria, tropia, and near point of convergence abnormality in a high school student population in Erbil city center.

To assess eye movements and binocular function in 14-year-olds with very low birthweight (VLBW: birthweight </= 1500 g) and 14-year-olds born at term but small for gestational age (SGA: birthweight < 10th percentile) in a population-based study. Ophthalmological examinations including measurements of heterophoria/tropia, near point of convergence, accommodative amplitude, stereopsis, nystagmus, saccades and smooth pursuit were performed in 51 adolescents with VLBW, 58 adolescents born SGA and in a control group consisting of 75 subjects of the same age. Latent or manifest strabismus, poor stereopsis, poor convergence and nystagmus were all more frequent in the VLBW group than in the control group. The VLBW group did not differ from the control group regarding accommodative amplitude or saccades and smooth pursuit. The SGA population did not differ from the control group in the measured variables. Premature birth with VLBW affects binocular visual functions negatively in adolescence, whereas birth small for date at term does not appear to be a risk factor for impaired eye movements and binocular function.

ABSTRACTPurpose: To determine the distribution of near point of convergence (NPC) and its related factors in 6 to 12-year-old children. Methods: In a cross-sectional study in 2015, the urban and rural children of Shahroud, north of Iran, were sampled. All rural schoolchildren were invited to the study, and in the urban area, we conducted random cluster sampling. Examinations included measurement of uncorrected and corrected visual acuity, manifest, subjective, and cycloplegic refraction. NPC and near point of accommodation (NPA) were measured with the best optical correction. Results: Of the 6624 sampled schoolchildren, 5620 participated in the study, and after applying the exclusion criteria, the final analysis was conducted on data from 5444 students; their mean age was 9.24 ± 1.71 years (6–12 years) and 53.6% (n = 2918) of them were male. Mean NPC was 8.08 cm [95% confidence interval (CI): 7.96–8.19]; 8.07 cm (95% CI: 7.92–8.22) in males and 8.08 cm (95% CI: 7.91–8.25) in females (p = 0.954). NPC significantly recessed with age (p < 0.001). Mean NPC in emmetropic, myopic, and hyperopic children were 8.13, 7.04, and 8.23 cm, respectively (p < 0.001). The multiple linear regression model revealed significant associations for NPC with age (coefficient = 0.10, 0.95% CI: 0.05–0.15, p < 0.001), spherical equivalent refraction (coefficient = 0.17, 95% CI: 0.10–0.24, p < 0.001), and NPA (coefficient = 0.83, 0.95% CI: 0.76–0.90, p < 0.001). Conclusion: Mean NPC in 6–12-year-old Iranian children was 8.08 cm, which is worse than values reported in previous studies. Mean NPC showed a slight recession with age. Myopic schoolchildren had the least remote and hyperopes had the most remote NPC values. More remote values of NPA were associated with receded NPC.

To determine the distribution of the near point of convergence (NPC) and its related factors in an elderly population in Tehran, Iran. This population-based cross-sectional study was conducted on the elderly population (60 years of age and over) of Tehran, Iran in 2019. The samples were selected using stratified random cluster sampling. The examinations included the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, unilateral and alternate cover test, ocular health examination, and NPC measurement. The mean age of the participants was 65.90 ± 4.56 years and 59.6% of them were females. The mean (95% CI) NPC in the total sample was 7.84 cm (95% CI: 7.65-8.03). The mean (95% CI) NPC in males and females was 7.92 cm (7.63-8.21) and 7.75 cm (7.54-7.97) (P = 0.338), respectively. The mean NPC increased from 7.8 cm (95% CI: 7.55-8.05) in the age group 60-64 years to 8.83 cm (95% CI: 7.47-10.2) in the age group ≥ 80 years (P > 0.05). The mean (95% CI) NPC in emmetropic, myopic, and hyperopic individuals was 7.67 cm (95% CI: 7.33-8.02), 7.96 cm (7.56-8.37), and 7.87 cm (7.63-8.11), respectively (P = 0.378). There was no statistically significant relationship between NPC with education level, smoking, diabetes mellitus (DM), and hypertension (HT). The NPC values found in this study were significantly lower (less remote) than the values reported in previous studies in similar age groups. The NPC had no significant relationship with age, sex, education level, smoking, DM, and HT.

To investigate the relationship between near point of convergence (NPC) and mild cognitive impairment (MCI) in the general elderly population. The present report is a part of the Tehran Geriatric Eye Study (TGES): a population-based cross-sectional study conducted on individuals 60 years of age and above living in Tehran, Iran using the multi-stage stratified random cluster sampling method. Cognitive status was assessed using the Persian version of the Mini-Mental State Examination (MMSE). All study participants underwent complete ocular examination including measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, cover testing, NPC measurement, and slit-lamp biomicroscopy. The data of 1190 individuals were analyzed for this report. The mean age of the participants analyzed was 66.82±5.42 (60-92y) and 728 (61.2%) of them were female. Patients with MCI had a significantly more receded NPC compared to subjects with normal cognitive status (10.89±3.58 vs 7.76±2.71 cm, P<0.001). In the multivariable logistic regression model and in the presence of confounding variables, a receded NPC was statistically significantly associated with an increased risk of MCI (odds ratio: 1.334, 95% confidence interval: 1.263 to 1.410, P<0.001). According to receiver operating characteristic (ROC) analysis, a cut point NPC> 8.5 cm (area under the curve: 0.764, P<0.001) could predict the presence of MCI with a sensitivity and specificity of 70.9% and 69.5%, respectively. A receded NPC can be clinically proposed as a predictor of MCI in older adults. It is recommended that elderly with a receded NPC>8.50 cm undergo detailed cognitive screening for a definite diagnosis of MCI. In this case, the necessary interventions can be carried out to slow down MCI progression to dementia.

ABSTRACTPurpose: To determine the prevalence of strabismus and amblyopia, and the distribution of the near point of convergence (NPC), in a population of children aged 4 to 6 years.Methods: In this cross-sectional study, preschoolers in Mashhad were sampled using a random multistage cluster sampling approach. Examinations were done after obtaining parental consent. All participants had measurements of uncorrected visual acuity, corrected visual acuity, and non-cycloplegic refraction, and they had near and far cover tests to determine tropia and phoria.Results: Of the 3765 selected children, 3701 participated in the study. The prevalence of tropia was 1.21% (95% confidence interval [CI]: 0.86–1.57). Near and near/far tropia was observed in 0.83% (95% CI: 0.53–1.12) and 0.39% (95% CI: 0.18–0.59), respectively. Tropia was significantly more prevalent in boys (P=0.005). The most common type of tropia was esotropia, 0.22% (95% CI: 0.07–0.37). Among participants, 63.92% (95% CI: 62.36–65.48) had phoria; prevalence of far, near, and near/far phoria was 0.22% (95% CI: 0.07–0.37), 60.47% (95% CI: 58.88–62.07), and 3.22% (95% CI: 2.65–3.8), respectively. Mean NPC was 5.1 cm (95% CI: 5.05–5.14). NPC increased by 0.08 cm per month of age (P=0.033) and was 0.10 cm higher in boys compared to girls (P=0.027). Based on NPC, 61.58% (95% CI: 59.99–63.17) were symptomatic. The prevalence of amblyopia was 0.41% (95% CI: 0.20–0.61). The type of amblyopia was anisometropic, strabismic, and isoametropic in 75%, 11.1%, and 8.5%, respectively.Conclusion: The prevalence of amblyopia in this study population was not high; however, the prevalence of tropia was average compared to previous studies in Iran. Describing NPC in a 4- to 6-year-old Iranian population for the first time, we found that NPC increased with age in this sample.

To prospectively evaluate the effectiveness of home-based computer vergence therapy for the treatment of binocular vision disorders in adults at least 3 months after an acquired brain injury. Eligibility criteria included presence of binocular dysfunction characterized by receded near point of convergence (≥6 cm break), insufficient positive fusional vergence at near (failing Sheard's criterion or <15△ blur or break), insufficient negative fusional vergence at near (<12△ blur or break), and/or reduced vergence facility at near (<15 cycles per minute with 12△BO/3△BI). Participants were prescribed 12 weeks of home-based computer vergence therapy. Phoria (cover test), negative fusional vergence, positive fusional vergence, near point of convergence, vergence facility, and symptoms (convergence insufficiency symptom survey [CISS]) were assessed at baseline and after 4, 8, and 12 weeks of prescribed therapy. ANOVA was used to evaluate change in each measure. Percentage successful was also determined. Nineteen participants were enrolled (mean age 45.4 ± 12.9 years); six participants were lost to follow-up. Baseline findings were orthophoria at distance, 7.2△ exophoria at near, near point of convergence break = 17.5 cm, near point of convergence recovery = 21.8 cm, negative fusional vergence = 12.3△, positive fusional vergence blur = 8.4△, vergence facility = 3.9 cycles per minute, and CISS = 32.1. ANOVA showed a statistically significant improvement for near point of convergence break (p = 0.002) and recovery (p < 0.001), positive fusional vergence blur (p < 0.0001), break (p < 0.0001), and recovery (p < 0.0001), negative fusional vergence blur (p = 0.037), break (p = 0.003), and recovery (p = 0.006), vergence facility (p < 0.0001), and CISS (p = 0.0001). The percentage of patients who were classified as "successful" or "improved" was 69% for near point of convergence (<6 cm or decrease of ≥4 cm), 77% for positive fusional vergence (>15△ and passing Sheard's criterion or increase of ≥10△), 77% for negative fusional vergence (≥12△ or increase of ≥6△), 62% for positive fusional vergence and near point of convergence composite, and 92% for vergence facility (15 cycles per minute or increase of 3 cycles per minute). The majority of participants who completed the study experienced meaningful improvements in signs and symptoms.

PurposeTo determine the distribution of the near point of convergence (NPC) and near point of accommodation (NPA) in a young student population in Iran.MethodsThe subjects were selected using a cluster sampling method. All students underwent optometry tests, including visual acuity measurement, refraction, and cover test, as well as ophthalmic examinations. The NPC and NPA were measured using an accommodative target (near Snellen chart).ResultsOf 1,595 students, the data of 1,357 were analyzed. The mean NPC and NPA in the total sample were 7.25 cm (95% confidence interval [CI], 7.02 to 7.48) and 9.99 cm (95% CI, 9.69 to 10.29), respectively. Older age was associated with an increase in the NPC, which increased from 6.98 cm in 18–20 years olds to 9.51 cm in those over 30 years. The NPA was significantly associated with age and refractive errors in the multiple linear regression model, increasing from 9.92 cm in 18–20 years olds to 11.44 cm in those over 30 years ( = 0.003). Hyperopic eyes had lower NPA than myopic and emmetropic eyes ( = 0.001). In younger age groups, the mean accommodation amplitude was lower than the mean Hofstetter value. Moreover, with age, especially after 30 years, the mean values surpassed those determined using the Hofstetter formula.ConclusionThe NPC values in this study were lower than those previously reported for identical age groups. The Hofstetter formula is not always an accurate predictor of the accommodation amplitude in the Iranian adult population.

To observe and analyze the effects of orthokeratology in patients with convergence insufficiency, exophoria, and myopia. Thirty patients (60 eyes) between 8 and 15 years old with myopia and convergence insufficiency exophoria treated with orthokeratology at the First Affiliated Hospital of the Baotou Medical College from December 2022 to December 2023 were prospectively enrolled. General information was gathered and examinations were performed at baseline and at 2 weeks and 1, 3, and 6 months after switching to orthokeratology lenses. Examinations included assessments of distance/near visual acuity, near point of convergence, distance and near horizontal phoria, near positive fusional vergence, and monocular amplitude of accommodation. The median age of the participants was 10 years (range: 8 to 15 years), and 40% were female. The baseline refractive error was -2.00 diopters (D) (range: -4.00 and -1.00 D). After 6 months of treatment, we found statistically significant differences in near point of convergence (95% confidence interval: -13.99 to -8.67), positive fusional vergence (95% confidence interval: 15.32 to 11.42), and monocular amplitude of accommodation (95% confidence interval: 6.62 to 4.51) compared with baseline. In addition, the mean pretreatment near horizontal phoria decreased from 6.83 ± 1.44 to -4.90 ± 1.29 prism diopters after the 6 months of treatment (95% confidence interval: -2.92 to -0.94). This study showed that the use of orthokeratology lenses with an increased compression factor of 1.75 D may improve near point of convergence, positive fusional vergence, and monocular amplitude of accommodation for the treatment of convergence insufficiency with myopia. [J Pediatr Ophthalmol Strabismus. 2025;62(4):252-257.].

Background: Malaria induces a recession of the near point of convergence and a reduction of the amplitude of accommodation of the eye with symptoms such as blurred vision at near, difficulty reading, asthenopia, exophoria at near, and low accommodative convergence ratio occurring, all these symptoms lead to an interference in visual functioning and performance. Artemether- Lumefantrine anti-malaria drug is widely used and very effective as a first line treatment for uncomplicated plasmodium falciparum malaria infection. There is a need to determine if artemether-lumefantrine can reverse the effects of malaria on the amplitude of accommodation and near point of convergence. Methods: This was a clinical study carried out using the convenient sampling method at the medical center and department of Optometry teaching clinic of the Federal University of Technology Owerri, Imo State, Nigeria to evaluate amplitude of accommodation and near point of convergence after treatment with artemether-lumefantrine. Informed consent was obtained from all subjects that participated in the study and ethical clearance from the Ethics Committee of the School of Health Technology, Federal University of Technology, Owerri. 143 subjects aged 18 to 30 years diagnosed with malaria were recruited for the study. The amplitude of accommodation was measured using the push-up to blur method with an accommodative target, and near point of convergence was determined using the push-up to break and recovery method with an accommodative target. Both measurements were taken after the diagnosis of malaria was made through laboratory analysis and before the administration of the drug. After drug administration, amplitude of accommodation and near point of convergence measurements were repeated 24-, 48-, 72-, and 336 hours. Effects of drug administration on parameters were analyzed using T-test and ANOVA. Results: There was a significant increase in the amplitude of accommodation with time following administration of artemether-lumefantrine drug combination (p&lt;0.001) while near point of convergence was not affected (p&gt;0.05). Conclusion: Artemether-lumefantrine used for the treatment of malaria countered the effect of malaria parasite on amplitude of accommodation by increasing it but had no significant effect on near point of convergence.

Background: Pre-presbyopes may suffer from ocular symptoms such as asthenopia of near work.Aim: This study aimed to evaluate near points of convergence, amplitudes of accommodation, and fusional vergence among pre-presbyopes with asthenopia symptoms.Setting: The study was conducted at El-Walidain Eye Hospital, Khartoum, Sudan in 2022.Methods: The study was a hospital-based prospective, including 107 pre-presbyopes aged 35–40 years who complained of asthenopia symptoms. Clinical examinations included an assessment of amplitude of accommodation, near point of convergence and fusional vergence.Results: The findings showed receded in near points of convergence and a decrease in the accommodation was highly significantly associated with increased age among emerging presbyopes with asthenopia symptoms (p = 0.0001). Conversely, positive and negative fusional vergence amplitudes were not significantly correlated with age with p = 0.109 and p = 0.355, respectively. Positive and negative fusional amplitudes were not significantly different between males and females (p ˃ 0.05). Esophoria was more common in pre-presbyopia 62 (57.4%) and exophoria 45 (43.6) with p = 0.503.Conclusion: The pre-presbyopes presented with low accommodation amplitude and receded near point of convergence, but without significant changes in positive and negative fusional vergence amplitudes.Contribution: This study added by demonstrating how early presbyopia altered accommodation amplitude and near point of convergence significantly while having no significant impact on amplitudes of positive and negative fusional vergence.

The aim of this study was to investigate the incidence of functional vision problems in a large unselected cosmopolitan population of primary school-age children and to investigate whether constant clinical criteria for functional vision problems would be implemented by the practitioners involved in the screening. Refractive errors, near point of convergence, stereopsis, strabismus, heterophoria and accommodative facility were assessed for 2697 children (3-12 years) of varying racial backgrounds living in Australia. The spherical component of the refractive error ranged from -7.75 to +9.50 D (mean +0.54 D, +/-0.79) with a distribution skewed towards hypermetropia; astigmatism ranged from 0 to 4.25 D (mean -0.16 D, +/-0.35). There was a trend towards less hypermetropia and slightly more astigmatism with age. Mean near point of convergence was 5.4+/-2.9 cm, heterophoria at far and near was 0.12+/-1.58delta exophoria and 1.05+/-2.53delta exophoria, respectively, 0.55% of children exhibited vertical phoria at near >0.5delta, accommodative facility ranged from 0 to 24 cycles per minute (cpm) (mean 11.2 cpm, +/-3.7), stereopsis varied from 20 to 800 s (") of arc with 50% of children having 40" or better. The prevalence of strabismus was particularly low (0.3%). Twenty percent of the children were referred for further assessment based on criteria of one or more of: stereopsis >70", accommodative facility <8 cpm, near point of convergence (NPC) >9 cm, near exophoria >10delta or near esophoria >5delta, shift in eso or exophoria > or = 4delta between distance and near, astigmatism > or = 1 D, myopia more than -0.75 D, or hyperopia >+1.50 D. Post-hoc analysis of the record cards seeking the reason for further assessment indicates that referrals appear to have been based upon clinical intuition rather than on a set number of borderline or unsatisfactory results.

Purpose To determine the prevalence of asthenopia and its associated factors in a sample of university students in Iran.MethodsIn this cross-sectional study, participants were selected using multistage cluster sampling. Presence of at least one of the 10 symptoms—foreign body sensation, diplopia, blurred vision, eye swelling, dry eye, eye pain, difficulty in sustaining visual operations, decreased visual acuity, tearing, and photophobia—was considered as asthenopia. Ocular examinations, including uncorrected/corrected visual acuity measurement, objective/subjective refraction, cover test, amplitude of accommodation (AA), and near point of convergence (NPC) were performed.ResultsOf the 1,462 students (mean age: 22.8 3.1 years), 73% were women. The age- and gender-standardized prevalence was 70.9% (95% confidence interval [CI]: 68.3–73.5), 39.8% (95% CI: 36.4–43.1), and 19.7% (95% CI: 16.0–23.3) based on the presence of at least one, two, and three symptoms, respectively. The prevalence was significantly higher in females (P = 0.048), hyperopic students (P 0.001), and astigmatic participants (P 0.001). The mean AA and NPC were 9.7 2.6 D and 10.2 4.2 D (P = 0.008) and 7.0 2.1 cm and 7.7 3.9 cm (P 0.001) in participants with and without asthenopia, respectively. Multiple regression model revealed age (28–29 years), astigmatism, and NPC as independent associated factors (odds ratios: 3.51, 1.61, and 0.91, respectively).ConclusionThis study shows relatively high prevalence of asthenopia in university students. Demographic factors and visual system disorders are important risk factors and timely correction of conditions may lead to decreased asthenopia.

Clinical relevance Botulinum toxin is commonly used for cosmetic facial rejuvenation and can result in pain at the injected site, bruising and ecchymosis, erythema and oedema, headache, diplopia, blurred vision, focal facial weakness. This study evaluates the impact of botulinum toxin on refractive error and binocular vision. Background Botulinum toxin (trade name: Dysport) is a neurotoxic protein which is made from a Gram‐positive anaerobic bacterium known as Clostridium botulinum. In this study, we aimed to evaluate the impact of Dysport injection on refractive error, near point of accommodation and convergence, and palpebral fissure height. Methods Twenty‐eight subjects were treated for facial wrinkles, using Dysport. A 500‐unit vial of Dysport was diluted with 2.5-ml preserved normal saline, and injected doses were 30-units for crow’s feet, six units for lower eyelid wrinkles, 25 to 50-units for glabellar lines (five points), and 20 to 40 for forehead creases on four points. The refractive error, near point of accommodation and convergence and palpebral fissure heights were assessed before and two weeks after injection. Results The participants comprised 23 women and five men at a mean age of 53.51 ± 14.1-years. The means of the equivalent sphere before and after injection were −0.07 ± 1.34 and −0.08 ± 1.35 (p = 0.36). The means of near point of accommodation monocularly before and after injection were 29.75 ± 6.16-cm and 26.75 ± 6.00, respectively. The means of near point of convergence before and after injection were 16.03 ± 5.27-cm and 15.55 ± 6.14, respectively (p = 0.30). The means of palpebral fissure height before and after injection were 10.33 ± 1.69-mm and 10.20 ± 1.46-mm, respectively. The changes in equivalent spherical refractive error, binocular near point of accommodation and convergence were not statistically significant. Conclusion Dysport injection for the correction of upper face animation lines, if performed at the appropriate sites and the appropriate concentration, has no significant impact on refractive error, near point of accommodation and convergence, and palpebral fissure height.

Background: Sensitive and specific screening methods are needed to identify athletes at risk of prolonged recovery after sport-related concussion (SRC). Convergence insufficiency (CI) is a common finding in concussed athletes. Purpose: To assess the relationship between CI and recovery after SRC at the initial office visit. Study Design: Case-control study; Level of evidence, 3. Methods: In this retrospective cohort study, 270 athletes (147 male, 123 female), mean ± SD age 14.7 ± 2.0 years (range, 10-21 years), with the diagnosis of SRC who presented for initial office visit between January 2014 and January 2016 were evaluated for near point of convergence (NPC). The athletes were categorized into 2 groups: normal near point of convergence (NPC ≤6 cm), and convergence insufficiency (NPC >6 cm). These athletes were then followed to determine recovery time. Results: Athletes presented for initial office visit at a mean of 5.2 ± 4.2 days (range, 1-21 days) after SRC. Half of the athletes had CI after SRC (50.4%; n = 136). Athletes with CI (NPC 12.3 ± 4.7 cm) took significantly longer to recover after SRC, requiring 51.6 ± 53.9 days, compared with athletes with normal NPC (4.1 ± 1.3 cm), who required 19.2 ± 14.7 days (P < .001). After controlling for potential confounding variables, CI significantly increased the odds of prolonged recovery (≥28 days from injury) by 12.3-fold (P < .001; 95% confidence interval, 6.6-23.0). CI screening correctly classified 75.2% of our sample with 84.2% sensitivity and 70.0% specificity. The positive predictive value for CI and prolonged recovery was 62.5%, and the negative predictive value was 88.1%. Conclusion: CI at the initial office visit identified athletes at increased risk of prolonged recovery after SCR. Clinicians should consider measuring NPC in concussed athletes as a quick and inexpensive prognostic screening method.

Background: Fusional vergence amplitude is the amount of convergence and divergence that can be induced before fusion is lost and fusional vergence amplitude controls heterophoria.Aim: This study aimed to investigate the relationship between near heterophoria, near fusional vergence (NFV), and near point of convergence (NPC).Setting: Al-Neelain Eye Hospital Khartoum, Sudan.Methods: A hospital-based prospective study from February to October 2019, included 230 patients with age range of 15–30 years and mean age and standard deviation of 19.46 ± 3.33 years. The alternate cover test with prism was used to measure near heterophoria and a prism bar was used to measure quantity of fusional vergence. All measurements were taken at near heterophoria (0.33 m). Then the associations between near heterophoria, NFV and NPC were assessed.Results: The most common heterophoria at near among the participants was exophoria: 200 (87.0%). Reported complaints of asthenopia were commonly found among these exophoric patients: 106 (86.9%) (P = 0.735). Positive fusional vergence (PFV) to the break point varied according to the forms of heterophoria (P = 0.003). Esophoria had a higher PFV to break point than exophoria (30.83 ± 8.79Δ compared to 25.59 ± 10.07Δ). Negative fusional vergence at the break and recovery points were higher among those with exophoria and lower in esophoria (P ˃ 0.05). The NPC differed by the type of heterophoria (P = 0.01), with exophoria and slightly receded NPC (8.38 cm ± 3.33 cm) than for participants with esophoria (6.77 cm ± 1.52 cm).Conclusions: Exophoria was the most common type of near heterophoria, with asthenopia being the most reported complaint. Esophoria was found to be strongly associated with high PFV. Exophoria, on the contrary, is related to significant high NFV at the blur, beak, and recovery point. The NPC differed significantly by the type of near heterophoria, with exophoria having more receded NPC compared to those with esophoria.Contribution: This study provides information on the commonest type of near heterophorias among a sample of Sudanese adolescents and young adults, namely exophoria. Near point of convergence and NFV at break and recovery points were significantly different according to forms of near heterophoria.