Exploring Correlations between Headaches and Refractive Errors in an Optometry Clinic Sample.

Background & Aim: The optometrist is often one of the professionals patients consult when they have headaches. The limitations inherent in previous studies on the topic limit the utilization of their findings. Therefore, the aim of conducting the present study was to explore correlations between headache and refractive errors in a clinical setting using extended classification criteria. Methods: The study design was cross-sectional, and sample comprised (headache group = 1062; non-headache group = 1095) participants aged 10-40 years who attended an optometry practice. During case-history taking, participants were classified as headache and non-headache group. Refraction, ocular health examinations, accommodative and vergence tests were performed. Headaches were sub-classified according to the anatomic location such as temporal, frontal, occipital, or diffuse, based on where pain was felt. Results: Temporal and temporo-frontal headaches were most frequent. Participants in the headache group numbered 1062 with mean age 25.1 ± 8.6; females 841 (79.1%) and males 221 (20.8%) while those in the no headache group numbered 1095 with mean age 25.3 ± 8.7; females 648 (59.1%). Low amount spheres and cylinders (p = 0.003) as well as hyperopic, and against-the-rule astigmatism (p = 0.012) and (p = 0.03) respectively were significantly more frequent in the headache group. Conclusion: Temporal headaches were most frequent. Patients with low spheres and cylindrical errors as well as hyperopic and against-the-rule astigmatism were significantly more prone to headaches. This study provides findings, which have not been reported. Findings have implications for clinical practice and highlights the need to compensate for low ametropia. A standard study protocol is recommended.

Gender and age distribution of refractive errors in an optometric clinical population

Aim: To determine the patterns of distribution of refractive errors in a clinical sample of patients examined in an optometry practice.MethodIn this retrospective study, the clinic records of 6687 patients aged 6 to 85 years comprising 2168 (32.2%) males and 4519 (67.5%) females were reviewed. Refractive error were analysed according to gender, age, as well as types and categories including axis of astigmatism using the vector power analysis method where the traditional sphero-cylinder was transformed into J0 (primary) and J45 (oblique) astigmatic components.ResultsOnly the analysis for right eye was reported as right and left spherical equivalent were similar. The mean with standard deviations for refractive errors were: Myopia: −1.95 ± 2.6, hyperopia: 1.04 ± 0.9, astigmatism: −1.22 ± 0.71 and anisometropia: −0.01 ± 2.5 DS. The distributions with significant changes included males that were significantly more myopic and astigmatic, while females were more hyperopic across the age groups. Furthermore, myopia decreased, while hyperopia, astigmatism and anisometropia increased with increasing age. Unique findings from this study include: myopia peaked earlier, second hyperopic shift commenced after age 82 years and the distribution of severity of astigmatism contrasts with previous understanding.ConclusionAlthough the patterns of distribution of refractive errors in patients aged 6 to 85 years corroborates previous findings, myopia and hyperopia peak, as well as severity of astigmatism were unique to the present study. Results from non-clinic populations will be useful to confirm trends reported in this study. (AU)

Correlations between clinical measures and symptoms: Report 2: Accommodative and vergence measures with symptoms

Aim: The aim of this study was to explore associations among clinical measures of accommodation and vergences with symptoms, which could facilitate the validation of the Convergence Insufficiency Symptoms Survey to screen for deficient clinical measures.MethodsUsing a multi-stage random cluster sampling, 1211 high school students (481 males and 730 females) between 13 and 18 years of age were selected and examined. Visual acuity, stereoacuity and suppression, refractive errors, near point of convergence, heterophoria and fusional vergences, as well as, amplitude of accommodation, accommodative response, facility and relative accommodation were evaluated. The validity of the Convergence Insufficiency Symptoms Survey to distinguish between children with and those without anomalies in the clinical measures were characterized using the Receiver Operation Curve, sensitivity and specificity of the tests.ResultsThe overall mean and standard deviation for symptoms score was 27.38 ± 11.04. Deficient accommodative measures revealed worse symptoms scores than did deficient vergence measures and children with deficient clinical measures had significantly higher mean symptoms scores. (p = 0.001) However, the correlations between defective clinical measures and symptoms were significant but relatively weak. The Receiver Operation Curve showed that the clinical measures with the highest sensitivities using the CISS (≥16) were: reduced amplitude of accommodation 0.63, 95% Confidence interval, 0.59−0.68%) accommodative facility 0.62 (95% Confidence interval, 0.58−0.67) and near point of convergence 0.60 (95% Confidence interval, 0.53−0.67).ConclusionDeficient clinical measures and symptoms of asthenopia are prevalent and correlated in the sample of school children studied. Overall, findings suggest that high school children with deficient clinical measures may be symptomatic when they perform intense near task compared to those without deficiencies. (AU)

Gender and age distribution of refractive errors in an optometric clinical population.

AIM: To determine the patterns of distribution of refractive errors in a clinical sample of patients examined in an optometry practice. METHOD: In this retrospective study, the clinic records of 6687 patients aged 6 to 85 years comprising 2168 (32.2%) males and 4519 (67.5%) females were reviewed. Refractive error were analysed according to gender, age, as well as types and categories including axis of astigmatism using the vector power analysis method where the traditional sphero-cylinder was transformed into J0 (primary) and J45 (oblique) astigmatic components. RESULTS: Only the analysis for right eye was reported as right and left spherical equivalent were similar. The mean with standard deviations for refractive errors were: Myopia: -1.95 ± 2.6, hyperopia: 1.04  ± 0.9, astigmatism: -1.22 ± 0.71 and anisometropia: -0.01 ± 2.5 DS. The distributions with significant changes included males that were significantly more myopic and astigmatic, while females were more hyperopic across the age groups. Furthermore, myopia decreased, while hyperopia, astigmatism and anisometropia increased with increasing age. Unique findings from this study include: myopia peaked earlier, second hyperopic shift commenced after age 82 years and the distribution of severity of astigmatism contrasts with previous understanding. CONCLUSION: Although the patterns of distribution of refractive errors in patients aged 6 to 85 years corroborates previous findings, myopia and hyperopia peak, as well as severity of astigmatism were unique to the present study. Results from non-clinic populations will be useful to confirm trends reported in this study.

Correlations between clinical measures and symptoms: Report 2: Accommodative and vergence measures with symptoms.

AIM: The aim of this study was to explore associations among clinical measures of accommodation and vergences with symptoms, which could facilitate the validation of the Convergence Insufficiency Symptoms Survey to screen for deficient clinical measures. METHODS: Using a multi-stage random cluster sampling, 1211 high school students (481 males and 730 females) between 13 and 18 years of age were selected and examined. Visual acuity, stereoacuity and suppression, refractive errors, near point of convergence, heterophoria and fusional vergences, as well as, amplitude of accommodation, accommodative response, facility and relative accommodation were evaluated. The validity of the Convergence Insufficiency Symptoms Survey to distinguish between children with and those without anomalies in the clinical measures were characterized using the Receiver Operation Curve, sensitivity and specificity of the tests. RESULTS: The overall mean and standard deviation for symptoms score was 27.38 ±â€¯11.04. Deficient accommodative measures revealed worse symptoms scores than did deficient vergence measures and children with deficient clinical measures had significantly higher mean symptoms scores. (p = 0.001) However, the correlations between defective clinical measures and symptoms were significant but relatively weak. The Receiver Operation Curve showed that the clinical measures with the highest sensitivities using the CISS (≥16) were: reduced amplitude of accommodation 0.63, 95% Confidence interval, 0.59-0.68%) accommodative facility 0.62 (95% Confidence interval, 0.58-0.67) and near point of convergence 0.60 (95% Confidence interval, 0.53-0.67). CONCLUSION: Deficient clinical measures and symptoms of asthenopia are prevalent and correlated in the sample of school children studied. Overall, findings suggest that high school children with deficient clinical measures may be symptomatic when they perform intense near task compared to those without deficiencies. In addition, although validated for convergence insufficiency, the Convergence Insufficiency Symptoms Survey could barely distinguish between children with and without defective clinical measures. Findings highlight the need for and provide baseline data towards possible validation of a fast and reliable screening tool for vision anomalies. Further studies on similar populations are needed to confirm these findings and add to knowledge base.

Correlations between clinical measures and symptoms: Report 1: Stereoacuity with accommodative, vergence measures, and symptoms.

AIM: The aim of this study was to explore associations between reduced stereoacuity and clinical measures of accommodation, vergences, and symptoms which could facilitate the development of quick and reliable screening tools. METHODS: Using a multi-stage random cluster sampling, 1211 high school students (481 males and 730 females) between 13 and 18 years of age, were selected and examined. Visual acuity, stereoacuity and suppression, refractive errors, near point of convergence, heterophoria and fusional vergences, as well as, amplitude of accommodation, accommodative response, facility and relative accommodation were evaluated. Correlations among variables and the validity of Randot stereoacuity to distinguish between children with and without defective clinical measures as well as symptomatic versus asymptomatic children were characterized by the sensitivity and specificity of the tests. RESULTS: The overall mean stereoacuity was 43.9 ±â€¯25.23 s arc, and 18.9% [95% Confidence Interval, 16.6-21.4%)] of the participants had reduced stereoacuity (defined as ≥60). Stereoacuity values and symptoms scores were worse in children with defective clinical measures. The Receiver Operation Curve showed that maximum sensitivity and specificity was obtained with near point of convergence break (≥10 cm) of (0.70 95% confidence interval: 0.63-0.77) with Randot stereoacuity test (defined as ≥60 s arc). The correlations between reduced stereoacuity and symptoms scores was moderately strong and statistically significant (Pearson's, r = 0.507, p = 0.01). The Receiver Operation Curve showed that maximum sensitivity and specificity obtained with the Convergence Insufficiency Symptoms Survey was 0.57 (95% Confidence interval = 0.53-0.62, p = 0.001), sensitivity of 90.26%, and specificity 15.26% with the Randot stereoacuity test. CONCLUSION: Reduced stereoacuity, defective clinical measures and symptoms of asthenopia were prevalent among sample of school children studied. Randot stereoacuity test could fairly distinguish between defective and normal clinical measures; though the accuracy to differentiate between symptomatic and asymptomatic school children is poor. These findings highlight the need for validation of a simple and fast screening tool in school settings. Further studies to confirm above findings will be needed.

Associations between near work, outdoor activity, parental myopia and myopia among school children in Aba, Nigeria.

AIM: To assess the influence of near work, time outdoor and parental myopia on the prevalence of myopia in school children in Aba, Nigeria. METHODS: Primary and secondary school children aged between 8 and 15y were randomly recruited from 12 schools in Aba. Information on family history, near work and outdoor activity was obtained using myopia risk factor questionnaire. Cycloplegic refraction was performed using autorefraction technique. Myopia was defined as spherical equivalent refraction (SER) ≤-0.50 D in the poorer eye. Data were analysed for 1197 (male: 538 and female: 659) children with full relevant data. RESULTS: Risk of developing myopia was positively associated with parental myopia [odds ratio (OR): 6.80; 95%CI, 2.76-16.74; P<0.01) for one myopic parent and (OR: 9.47; 95%CI, 3.88-23.13; P<0.01) for two myopic parents, longer daily reading hour (OR: 1.21; 95%CI, 1.03-1.42; P=0.02) and less time outdoors (OR: 0.8; 95%CI, 0.74-0.87; P<0.01). CONCLUSION: Parental history of myopia is the most important risk factor associated with myopia. In addition, children with both parents being myopic has increased odds of developing myopia than those with one myopic parent. It is recommended therefore, that children spend more time outdoors as this could reduce the prevalence and progression of myopia.

Normative values for clinical measures used to classify accommodative and vergence anomalies in a sample of high school children in South Africa.

AIM: To determine normative values for stereoacuity, accommodative and vergence measures for high school populations. METHODS: Using a multi-stage random cluster sampling, 1211 children (481 males and 730 females) between 13 and 18 years of age, with a median age of 16 years, were selected. Visual acuity, stereoacuity and suppression, refractive errors, near point of convergence, heterophoria and fusional vergences, as well as, amplitude of accommodation, accommodative response, facility and relative accommodation were evaluated. RESULTS: Most data did not have a normal distribution. The range of normality for the vergence measures were: near point of convergence break, 5-10cm, recovery, 6-13cm, near lateral phoria, 2.5-6 prism dioptre (pd) (nasal), near vertical, orthophoria to 0.50pd, negative fusional vergence break, 12-23pd, recovery, 8-17pd, positive fusional vergence break, 16-35 and recovery 11-24pd. For accommodative measures, the range of normality for accommodative measures was: amplitude of accommodation, 12-18pd, accommodative response, plano to +0.75D, binocular accommodative facility, 5-12 cycles per minute (cpm), negative relative accommodation, 1.75-2.50DS, positive relative accommodation, -2.0 to -3.0DS and 17-69s arc for stereoacuity. CONCLUSION: This study provides norms for clinical measures which could be used to classify accommodative and vergence parameters for children aged 13-18 years in this population or beyond. Findings should be applied in the context of the measurement techniques and the associated limitations outlined in this report.

Refractive Error in a Sample of Black High School Children in South Africa.

SIGNIFICANCE: This study focused on a cohort that has not been studied and who currently have limited access to eye care services. The findings, while improving the understanding of the distribution of refractive errors, also enabled identification of children requiring intervention and provided a guide for future resource allocation. PURPOSE: The aim of conducting the study was to determine the prevalence and distribution of refractive error and its association with gender, age, and school grade level. METHODS: Using a multistage random cluster sampling, 1586 children, 632 males (40%) and 954 females (60%), were selected. Their ages ranged between 13 and 18 years with a mean of 15.81 ± 1.56 years. The visual functions evaluated included visual acuity using the logarithm of minimum angle of resolution chart and refractive error measured using the autorefractor and then refined subjectively. Axis astigmatism was presented in the vector method where positive values of J0 indicated with-the-rule astigmatism, negative values indicated against-the-rule astigmatism, whereas J45 represented oblique astigmatism. RESULTS: Overall, patients were myopic with a mean spherical power for right eye of -0.02 ± 0.47; mean astigmatic cylinder power was -0.09 ± 0.27 with mainly with-the-rule astigmatism (J0 = 0.01 ± 0.11). The prevalence estimates were as follows: myopia (at least -0.50) 7% (95% confidence interval [CI], 6 to 9%), hyperopia (at least 0.5) 5% (95% CI, 4 to 6%), astigmatism (at least -0.75 cylinder) 3% (95% CI, 2 to 4%), and anisometropia 3% (95% CI, 2 to 4%). There was no significant association between refractive error and any of the categories (gender, age, and grade levels). CONCLUSIONS: The prevalence of refractive error in the sample of high school children was relatively low. Myopia was the most prevalent, and findings on its association with age suggest that the prevalence of myopia may be stabilizing at late teenage years.

Characteristics of astigmatism in Black South African high school children.

BACKGROUND: Astigmatism impairs vision at various distances and causes symptoms of asthenopia which negatively impacts reading efficiency. OBJECTIVE: The aim of conducting this study was to determine the prevalence and distribution of astigmatism and its relationship to gender, age, school grade levels and spherical ametropia. METHODS: Using a multi-stage random cluster sampling, 1589 children who included 635 (40%), males, and 954 (60%), females were selected from 13 out of a sample frame of 60 schools. Their ages ranged between 13 and 18 years with a mean of 15.81±1.56 years. The parameters evaluated included visual acuity using the LogMAR chart and refractive errors measured using an autorefractor and then refined subjectively. Axis of astigmatism was presented in the vector method where positive values of J0 indicated with-the-rule, negative values described against-the-rule and J45 represented oblique astigmatism. RESULTS: The mean cylinder power was -0.09 ± 0.27 and mainly with-the-rule, J0 = 0.01 ± 0.11. The overall prevalence of clinically significant astigmatism (≤ - 0.75 cylinder) in the sample was 3.1% [(95% Confidence interval = 2.1-4.1%)]. Cylinder of at least - 0.25 power was considered to classify astigmatism types. Thus, the estimated distributions of types of astigmatism were: axis- 11.5%, sphero-astigmatism 10.1% and magnitude-astigmatism 11.2% while 67.2% had no cylinder of any magnitude. CONCLUSION: The prevalence of astigmatism is relatively low in this population studied. Older children and those in high school grade levels were more likely to have with-the-rule or against-the-rule astigmatism. The prevalence of astigmatism were comparable within but not across regions.

Accommodative Anomalies in a Sample of Black High School Students in South Africa.

PURPOSE: Accommodative anomalies cause asthenopia and affect student reading efficiency and academic performance. The aim of conducting this study was to determine the prevalence and distribution of accommodative anomalies (insufficiency, excess and infacility) in relation to demographic variables (sex, age, school grade level and study location). METHODS: Study participants comprised 1,211 children (481 male and 730 female), with age range 13-19 years. Visual functions evaluated included refractive error, accommodative amplitude, accuracy, facility and relative accommodation. RESULTS: A total of 242 participants (20.2%) had accommodative anomalies. Prevalence estimates were; accommodative infacility 12.9% (95% confidence interval, CI, 10.9-14.7%), accommodative insufficiency 4.5% (95% CI 3.4-5.8%) and accommodative excess 2.8% (95% CI 1.9-3.8%). There were no significant differences based on sex, school grade level or study site, except in the prevalence of accommodative infacility, which was significantly higher in the younger grade level than the older (P=0.027). CONCLUSION: The study fills a gap in the literature in providing data on predominantly black South African students. The prevalence estimates for accommodative insufficiency and excess found in the sample studied are relatively low, while that of accommodative infacility is high. Accommodative anomalies were not markedly associated with demographic variables except for the prevalence of accommodative infacility, which was significantly higher in the younger grade level than the older. Identification and referral are important steps towards diagnosis and treatment of accommodative anomalies. Future studies on differences in prevalence of accommodative anomalies among different racial populations will be relevant.

Vergence anomalies in a sample of high school students in South Africa.

AIM: To study the prevalence of nearpoint vergence anomalies (convergence insufficiency, convergence excess and fusional vergence dysfunction) and association with gender, age groups, grade level and study site (suburban and rural). METHODS: The study design was cross sectional and data was analyzed for 1201 high school students aged 13-19 years who were randomly selected from 13 high schools in uMhlathuze municipality. Of the total sample, 476 (39.5%) were males and 725 (60.5%) were females. The visual functions evaluated included refractive errors, heterophoria, near point of convergence, accommodative functions and fusional vergences. Possible associations between vergence anomalies and demographic variables (gender, age groups, school grade levels and study site) were explored. RESULTS: Prevalence estimates were 11.8%, 6% and 4.3% for low suspect, high suspect and definite convergence insufficiency, and 1.9% for the pseudo convergence insufficiency. Convergence excess prevalence was 5.6%, and fusional vergence dysfunction was 3.3%. The prevalence of low suspect CI was significantly higher in suburban than in rural participants (p=0.01), the reverse was the case for pseudoconvergence insufficiency while the prevalence of convergence excess was significantly higher in the younger than in the older age group (p=0.02). No other category showed any statistically significant associations with vergence anomalies. CONCLUSION: The prevalence estimates for vergence anomalies in a sample of black high school students in South Africa were relatively low. Only study location and age influenced some vergence anomalies. Identification and referrals are important steps toward diagnosis and treatment for vergence anomalies. Further studies to compare vergence anomalies in various racial populations will be relevant.

Ophthalmic manifestations of children with Down syndrome in Port Harcourt, Nigeria.

AIM: The aim of this study was to provide a profile of oculo-visual anomalies in children with Down syndrome (DS) in Port Harcourt, Nigeria. METHODS: This comparative study assessed the visual functions of 120 children (42 DS and 78 developmentally normal children). The visual functions evaluated and the techniques used were: visual acuity (Snellen illiterate chart and Lea picture charts), refraction (static retinoscopy with cyclopegia), ocular alignment (cover test), near point of convergence (pen and rule), and external examinations and fundoscopy. RESULTS: A total of 42 children with DS (22 males, 20 females, mean age 11.43 ± 6.041 years) and control group of 78 normal children (36 females, 42 males) with mean age 6.63 ± 1.98 years were examined. Of the 42 DS children, visual acuity was less than 6/18 in eight and one of the DS and control groups, respectively. Visual acuity could not be checked conventionally in eleven participants from the DS group due to poor response. The main findings were: DS compared to control group showed refractive errors of 76.2% (half of which was from myopia) vs 14.1% (only 10% due to myopia). There was a statistically significant difference in total refractive errors between the Down syndrome group and the control group (P = 0.001, χ(2) = 18.29). Strabismus was 9.5% (75% esotropia) vs 0%, and there was a statistically significant difference (P = 0.001, χ(2) = 5.01), nystagmus was 4.8% v 0%, conjunctivitis 19.05% vs 8.97%, and keratitis 7.14% vs 0%, which was statistically significant (P = 0.05, χ(2) = 2.90). CONCLUSION: Refractive errors were prevalent in a sample of children with DS in Port Harcourt, Nigeria, whereas the prevalence of ocular diseases was low when compared to age-matched control participants. This study highlights the need for ophthalmic care in children with DS. Routine eye care such as the use of spectacles when necessary is recommended for people with DS at all ages to improve their educational and social needs as well as overall quality of life.