Does Hofstetter's equation predict the real amplitude of accommodation in children?

Comparing clinical measures of near point of convergence and accommodation from the lateral canthus and browline in a paediatric and adolescent population

PURPOSE

Clinicians measure the near point of convergence (NPC) and the amplitude of accommodation (AA) from the spectacle plane, the bridge of the nose or the lateral canthus when assessing visual function. These values are compared to standard clinical criteria to diagnose vergence and accommodation deficits, despite varying reference points. This prospective study explored measuring relative to the spectacle plane and from the lateral canthus for NPC and monocular AA, and the resulting clinical implications of diagnosing visual deficits.

METHODS

Participants were seen by a single clinician for an eye examination. NPC was measured from the forehead and the lateral canthus of the right eye. Monocular AA was measured from the brow and the lateral canthus. Differences between measurements were analysed using non-parametric statistical tests including Wilcoxon Signed Rank, as well as linear regression and a linear mixed effects model to adjust for inter-eye correlation and repeated measures. Chi-square tests were used to assess differences in rates of abnormal findings.

RESULTS

Data were collected from 70 participants (53% female, median age 13 [11-15] years). On average, measuring NPC from the lateral canthus yielded a value 1.8 cm higher than measuring from the forehead. Measuring AA from the lateral canthus resulted in an average difference of 1.5 cm compared to measuring from the brow. A total of 39% and 76% of subjects failed NPC compared to clinical norms when measured from the forehead or the lateral canthus, respectively, while 7% and 40% failed AA when measured from the brow or the lateral canthus, respectively.

CONCLUSION

With the variable anatomy of the eye, it is imperative to account for the measurement point when assessing visual function. Measuring from the lateral canthus greatly increased the failure rates for NPC and AA compared with measuring from the forehead and brow, respectively.

The Relationship between Anxiety, Visual Function, and Symptomatology in University Students

Mental health concerns have emerged at the university level, with the psychological well-being of students being increasingly affected. This cross-sectional study investigated the proportion of university students having anxiety, and its effects on their visual function and symptomatology. We included 41 students (26.1 ± 4.8 years), and their visual function was assessed through several tests to produce a general visual performance index (VPI). The visual symptomatology was studied using the Conlon Visual Discomfort Survey and the Quality of Vision (QoV) questionnaire. The students were classified into two groups according to the Generalized Anxiety Disorder Screener (GAD-7) test ("no anxiety" and "anxiety" groups). The visual function evaluation indicated significantly worse VPI in the anxiety group (p = 0.047). These students also showed significantly higher scores in the Conlon survey (p = 0.004) and two subscales of the QoV questionnaire: symptom severity (p = 0.041) and symptom bothersomeness (p = 0.013). Moreover, the multiple linear regression model showed a significant association between visual discomfort according to the Conlon questionnaire and the level of anxiety (r = 0.405; R2 = 0.164; B = 0.405; p = 0.012). It is important to study the influence of psychological factors on vision, not only for refractive error, but also for binocular and accommodative disorders.

Precision Concussion Management: Approaches to Quantifying Head Injury Severity and Recovery

Mitigating the substantial public health impact of concussion is a particularly difficult challenge. This is partly because concussion is a highly prevalent condition, and diagnosis is predominantly symptom-based. Much of contemporary concussion management relies on symptom interpretation and accurate reporting by patients. These types of reports may be influenced by a variety of factors for each individual, such as preexisting mental health conditions, headache disorders, and sleep conditions, among other factors. This can all be contributory to non-specific and potentially misleading clinical manifestations in the aftermath of a concussion. This review aimed to conduct an examination of the existing literature on emerging approaches for objectively evaluating potential concussion, as well as to highlight current gaps in understanding where further research is necessary. Objective assessments of visual and ocular motor concussion symptoms, specialized imaging techniques, and tissue-based concentrations of specific biomarkers have all shown promise for specifically characterizing diffuse brain injuries, and will be important to the future of concussion diagnosis and management. The consolidation of these approaches into a comprehensive examination progression will be the next horizon for increased precision in concussion diagnosis and treatment.

Evidence of the Amplitude of Accommodation of School-Going Children in the 21st Century

Purpose

The study sought to compare the normative amplitude of accommodation (AoA) in school-going children from studies in the 21st century, based on pooled estimates from meta-analyses, to assess their agreement to Hofstetter's average formula.

Methods

A PRISMA checklist was used to conduct the review. PubMed, EBSCOHOST and Medline electronic databases were employed, and hand searching resulting in 259 studies up to July 2021. After title and abstract screening, 12 studies underwent full-text screening, resulting in five studies for data extraction. The pooled effect size was determined using meta-analyses for sub-groups by age. A one-sample t-test was used to compare the pool-effect size estimates (monocular) to the expected AoA from Hofstetter's average formula.

Results

The comparison of pool estimates of AoA with the expected Hofstetter's average formula for the age sub-groups showed significant mean differences for: six-year olds: mean difference of -3.4 D (95% CI: -5.85; -1.04; p = 0.025); nine-year olds: mean difference of -4.1D (95% CI: -7.95; -0.20; p = 0.043); ten-year olds: mean difference of -4.6D (95% CI: -8.57; -0.54; p = 0.035) and 11-year olds: mean difference of -5.2 D (95% CI: -8.06; -2.40; p = 0.005). According to the quality assessment tool used, overall, the body of evidence was of good quality.

Conclusion

Hofstetter's prediction of normative amplitude of accommodation today may over-estimate for children aged six, nine, 10 and 11. The observed under-accommodation estimates from these comparisons may warrant consideration in assessing for a larger lag of accommodation in these age groups with myopia or pre-myopia, as part of the surveillance for progression.

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

Purpose

To 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.

Methods

This 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).

Results

Several 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.

Conclusions

In 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.

Correlation Near Point of Convergence and Amplitude Accommodation with School Myopia Progression at Near Activity in Badung Regency

School myopia is a term that is used for the development of myopia at school age. The Child Heart and Health Study in England (CHASE) 2010, the prevalence of myopia in Southeast 25,2% at school age. The risk factor for school myopia more complex and one of the environmental factors were near activity. Accommodation, convergence, and miotic pupil are third signs when we look closely. Convergence and accommodation were measured with Near Point of Convergence (NPC) and Amplitude Accommodation (AA). This research aims to know the correlation between NPC and AA with school myopia progression. Research location at Sibang Gede 1st elementary school, Kuta 1st elementary school, Jimbaran 4th elementary school, and Kerobokan Kelod 2nd elementary school. The sample was obtained by Convenience sampling, Stratified Sampling, and Consecutive sampling techniques. Data were analyzed and searching for correlation Near Point of Convergence (NPC), Amplitude Accommodation (AA), and myopia progression was done by bivariate and multivariate analysis with age, gender, and myopic parent. This Research has 125 sample who mostly female 56 %, age at 7 yo 24.8%, median near activity 78 Dh/ week, myopic parent 27.2%. Correlation NPC showed inversely to progression of myopia (NPC Break r = -0.332, p<0.001; NPC Recovery r = -0.335, p<0.001). Correlation AA and progression of myopia showed positive correlation (AA Binocular r = 0.287, p=0.001; AA RE r = 0.226, p=0.017; AA LE r = 0.261, p=0.07). Age has correlation with progression of myopia with (p<0.05). There is a correlation between NPC and AA with school myopia progression at near activity in Badung Regency. Smaller NPC was correlated with progression of myopia and higher AA was correlated with progression of myopia although age was correlated with myopia progression.

Strabismus, stereoacuity, accommodation and convergence in young adults born premature and screened for retinopathy of prematurity

PURPOSE

The aim of the study was to evaluate strabismus, stereoacuity, accommodation and convergence in prematurely born young adults; screened for retinopathy of prematurity in the neonatal period and compare with term-born individuals of the same age.

MATERIALS AND METHODS

The study participants included 59 prematurely born individuals with a birthweight of ≤1,500 grams and 44 term-born controls, all born during 1988-1990 in Stockholm County, Sweden. Ocular alignment was assessed with a cover test, stereoacuity with the TNO stereo test and the amplitude of accommodation and the near point of convergence with the Royal Air Force Rule.

RESULTS

Seven of 59 (12%) preterms had manifest strabismus, 4/59 (7%) had esotropia and 3/59 (5%) exotropia. One of 44 (2%) controls had esotropia; no other controls had manifest strabismus. Stereoacuity was within normal limits in 38/59 (64%) preterms and 43/44 (98%) controls, p < 0.01; the difference remained after excluding those with strabismus. A neurological complication at 2.5 years of age was the strongest risk factor for subnormal stereoacuity within the preterm group after excluding those with strabismus. The mean amplitude of accommodation was poorer in the preterms than the controls in better (p < 0.05) and worse eyes (p < 0.05). The preterms were more likely to have an amplitude of accommodation below the minimum, according to Hofstetter's equation. There were no differences between the groups regarding the near point of convergence.

CONCLUSION

Prematurely born young adults had a higher prevalence of strabismus, reduced stereoacuity and worse amplitude of accommodation than term-born controls.

Improvement of Presbyopia Using a Mixture of Traditional Chinese Herbal Medicines, Including Cassiae Semen, Wolfberry, and Dendrobium huoshanense

Background

Presbyopia is a primary cause of a decline in near vision. In this study, we developed a new mixed herbal medicine to retard presbyopic progression and increase the amplitude of accommodation (AA), which is beneficial for near vision.

Methods

A total of 400 participants between the ages of 45 and 70 years were recruited. We designed the mixed herbal drug to include Cassiae Semen (200 mg), wolfberry (200 mg), and Dendrobium huoshanense (DD) (40 mg) in one capsule. In experiment 1, the recruited subjects were directed to perform a push-up test to measure their AA; this was then converted to the additional diopters of reading glasses. In experiment 2, 240 subjects took three capsules daily for six months and then stopped medical therapy for a six-month follow-up. In experiment 3, 160 subjects were randomly categorized into four groups: a placebo group, low-dose group (LDG) (1 capsule daily), middle-dose group (MDG) (two capsules daily), and high-dose group (HDG) (three capsules daily). The 160 volunteers took different doses for six months and then stopped treatment, accompanied by another six-month follow-up. In experiments 2 and 3, the change in AA, uncorrected far visual acuity (UFVA), and uncorrected near visual acuity (UNVA) were recorded each month for one year.

Results

In experiment 1, AA was found to decrease with age and a great deal of additional power was needed in older individuals. In experiment 2, the mean AA reached a maximum value of 2.1D (P < 0.05) after six months, while the UNVA improved by about two to three lines of a Jaeger chart in most of the subjects. At nine months, all the means decreased slightly to 2.0 D (P < 0.05). This meant that the mixed herbal medicine could still maintain AA for another three months because the herbal therapy was stopped at the seventh month. In experiment 3, the maximal AA was 2.8D, 2.9D, and 3.2D (P < 0.05) in the LDG, MDG, and HDG after six-month treatments, respectively. Experiment 3 showed that AA gain occurred in a dose-dependent manner; the higher the dose, the greater the AA value.

Conclusion

Only two studies on the use of herbal drugs for presbyopia have been reported in PubMed. In our study, we found that taking a mixed herbal drug caused an excellent gain in AA. This is the first study to report that the characteristics of the new herbal regimen could retard and even ameliorate presbyopia.

Accommodative and convergence anomalies in patients with opioid use disorder

Clinical relevance: Considering the significant relationship between opioid abuse and some accommodative and convergence disorders, opioid use should be considered in the differential diagnosis and will directly affect the management plan.Background: To determine the prevalence of accommodative and convergence anomalies and their related factors in a population of male young adults with opioid use disorder (OUD).Methods: This cross-sectional study was conducted using a convenience sampling method in 2019. The study sample included male young adults with OUD who had been referred to a specialised drug-dependence rehabilitation centre in Mashhad, Iran. The diagnosis of OUD was made by a psychologist based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria. All patients underwent complete optometric examinations.Results: Eighty male young adults with OUD were included in this study. The mean age of participants was 30.5 ± 3.9 years (age range 19 to 35 years). The prevalence of accommodative and convergence disorders was 33.75% (95% CI: 23.55-45.19) and 25.00 (95% CI: 15.99-35.94), respectively. Accommodative insufficiency (22.5%, 95% CI: 13.91-33.21) had a higher prevalence than accommodative excess (3.75%, 95% CI: 0.78-10.57) and accommodative infacility (7.50%, 95% CI: 2.80-15.61). Convergence insufficiency (18.75%, 95% CI: 10.89-29.03) had a higher prevalence compared to convergence excess (3.75%, 95% CI: 0.78-10.57) and basic exophoria (2.50%, 95% CI: 0.30-8.74). According to the multiple logistic regression, a significant inverse relationship was observed between pupil size with accommodative insufficiency (OR = 0.45), accommodative infacility (OR = 0.67), and convergence insufficiency (OR = 0.55).Conclusion: The results of the present study showed a higher prevalence of some accommodative and convergence disorders in OUD patients compared to the prevalence reported in previous studies conducted on the normal populations with a similar age range.

Psychometric Assessment of the Persian Version of the Revised Convergence Insufficiency Symptom Survey in Young Adults with Convergence Insufficiency

Purpose:

To translate the Convergence Insufficiency Symptom Survey (CISS) to Persian and to assess its validity and reliability in a group of young adult Iranian patients with convergence insufficiency (CI).

Methods:

The questionnaire was translated in backward and forward phases. Face validity was measured using a 6-point scale (very weak, weak, moderate, good, very good, best), and a score of ≥4 for each item indicated an acceptable face validity. The content validity was assessed using three indices of relevancy, clarity, and comprehensiveness. Relevancy and clarity were checked for each item and for the whole scale using a 4-point scale (1-undesirable, 2-relatively desirable, 3-desirable, 4-completely desirable), and Item Content Validity Index (I-CVI) and Scale Content Validity Index (S-CVI) were calculated for the above indices. Comprehensiveness was measured at the scale level using a 4-point scale (1-incomprehensive, 2-relatively comprehensive, 3-comprehensive, 4-totally comprehensive), and S-CVI was calculated. The internal consistency and test-retest reliability were assessed using Cronbach's alpha coefficient and interclass correlation coefficient (ICC), respectively. To evaluate discriminant validity, CI was categorized into mild, moderate, and severe stages, and the mean overall CISS score was compared between these groups.

Results:

Thirty CI patients aged 18–34 years participated in this study. On face validity assessment, all items finally had a score of ≥4. As for relevancy and clarity, I-CVI was above 80% for all items, and S-CVI was 98.8% and 96.6%, respectively. The S-CVI was 100% for comprehensiveness. The overall Cronbach's coefficient and ICC were 0.77 and 0.95, respectively. There was a significant difference in the overall score between the three severity groups.

Conclusion:

The Persian CISS is a valid and reliable tool for clinical and research applications.

Effectiveness of vergence/accommodative therapy for accommodative dysfunction in children with convergence insufficiency

PURPOSE

To determine the effectiveness of office-based vergence/accommodative therapy for improving accommodative amplitude and accommodative facility in children with symptomatic convergence insufficiency and accommodative dysfunction.

METHODS

We report changes in accommodative function following therapy among participants in the Convergence Insufficiency Treatment Trial - Attention and Reading Trial with decreased accommodative amplitude (115 participants in vergence/accommodative therapy; 65 in placebo therapy) or decreased accommodative facility (71 participants in vergence/accommodative therapy; 37 in placebo therapy) at baseline. The primary analysis compared mean change in amplitude and facility between the vergence/accommodative and placebo therapy groups using analyses of variance models after 4, 8, 12 and 16 weeks of treatment. The proportions of participants with normal amplitude and facility at each time point were calculated. The average rate of change in amplitude and facility from baseline to week 4, and from weeks 4 to 16, were determined in the vergence/accommodative therapy group.

RESULTS

From baseline to 16 weeks, the mean improvement in amplitude was 8.6 dioptres (D) and 5.2 D in the vergence/accommodative and placebo therapy groups, respectively (mean difference = 3.5 D, 95% confidence interval (CI): 1.5 to 5.5 D; p = 0.01). The mean improvement in facility was 13.5 cycles per minute (cpm) and 7.6 cpm in the vergence/accommodative and placebo therapy groups, respectively (mean difference = 5.8 cpm, 95% CI: 3.8 to 7.9 cpm; p < 0.0001). Significantly greater proportions of participants treated with vergence/accommodative therapy achieved a normal amplitude (69% vs. 32%, difference = 37%, 95% CI: 22 to 51%; p < 0.0001) and facility (85% vs. 49%, difference = 36%, 95% CI: 18 to 55%; p < 0.0001) than those who received placebo therapy. In the vergence/accommodative therapy group, amplitude increased at an average rate of 1.5 D per week during the first 4 weeks (p < 0.0001), then slowed to 0.2 D per week (p = 0.002) from weeks 4 to 16. Similarly, facility increased at an average rate of 1.5 cpm per week during the first 4 weeks (p < 0.0001), then slowed to 0.6 cpm per week from weeks 4 to 16 (p < 0.0001).

CONCLUSION

Office-based vergence/accommodative therapy is effective for improving accommodative function in children with symptomatic convergence insufficiency and coexisting accommodative dysfunction.

Accommodative Insufficiency: Prevalence, Impact and Treatment Options

PURPOSE

Accommodative insufficiency (AI), defined as the inability to stimulate accommodation in pre-presbyopic individuals, has gained much attention over recent years. Despite the enormity of the available information, there is a significant lack of clarity regarding the criteria for definition, methodology adopted for testing and diagnosis, and the varied prevalence across the globe. This review aims to gather evidence that is pertinent to the prevalence, impact and efficacy of available treatment options for AI.

METHODS

PubMed, Google Scholar and Cochrane Collaboration search engines were used with the keywords prevalence, accommodative insufficiency, symptoms, plus lens, vision therapy and treatment. Peer-reviewed articles published between 1992 and 2019 were included in the review. After reviewing the studies for study methodology and robustness, 83 articles were chosen for this literature review.

RESULTS

The prevalence of AI ranges between <1.00% and 61.6% across studies. The prevalence shows considerable variation across ethnicities and age groups. There is significant variation in the study methodology, diagnostic criteria and number of tests performed to arrive at the diagnosis. Not many studies have explored the prevalence beyond 20 years of age. The prevalence of AI is high among children with special needs. There is no high-quality evidence regarding the standard treatment protocol for AI. Both vision therapy and low plus lenses have shown efficacy in independent studies, and no studies have compared these two treatment options.

CONCLUSION

The understanding of AI prevalence is currently limited owing to the lack of a standard set of diagnostic criteria and wide variations in the study methodology. There is a lack of high-quality evidence suggesting the best possible treatment for AI. The current gaps in the literature have been identified and future scope for exploration is elucidated.

Diurnal variations of amplitude of accommodation in different age groups

Clinical assessment of amplitude of accommodation (AA) involves measuring the ability of the eye to change its optical power and focus on near tasks/objects. AA gradually decreases with increasing age. However, details of age-related diurnal changes in AA are not well known. This study compared diurnal changes in AA in the adolescents, the twenties, and the forties age groups. Measurement of AA using the push-up method was performed in six sessions at two-hourly intervals for 154 subjects (48, 56, 50 subjects for the adolescents, twenties, and forties age groups, respectively); the first measurements were taken from 9:00–10:00 a.m. and the final measurements from 7:00–8:00 p.m. The mean AA was 14.67 D (highest: 16.15 D in the 3:00–4:00 p.m. session, lowest: 13.35 D in the 9:00–10:00 a.m. session) for the adolescent group; 11.13 D (highest: 11.69 D in the 3:00–4:00 p.m. session; lowest: 10.61 D in the 9:00–10:00 a.m. session) in the twenties group; and 5.53 D (highest: 5.80 D in the 1:00–2:00 p.m. session, lowest: 5.11 D in the 7:00–8:00 p.m. session) in the forties age group. The measured AA showed significant difference between sessions; however, diurnal variations were greater in the younger groups. The measured AA was low at the beginning of the day in the adolescents and twenties groups and low at the end of the day in the forties age group. All age groups showed a high AA during the afternoon hours of the day (1:00–4:00 p.m.). Since the difference between each session was larger in younger subjects, AA should be evaluated while taking the age-related diurnal variations into account.

Accommodative insufficiency in a student population in Iran

PURPOSE

To determine the prevalence of accommodative insufficiency (AI) and its relation with age, gender, and refractive errors in a college-age student population in Iran.

METHODS

The present study was conducted cross-sectionally in 2017. All students had optometric tests including measurement of visual acuity, objective and subjective refraction, as well as binocular vision and accommodative examinations. Amplitude of accommodation was measured with the Donders' push-up method using the Royal Air Force (RAF) rule. Monocular accommodative facility was measured with ±2.00diopter flipper lenses. The accommodative response was tested using dynamic retinoscopy with the monocular estimation method (MEM).

RESULTS

The prevalence of AI in the studied population was 4.07% (95% CI: 2.61-5.52). The rate was 6.04% (95% CI: 3.58-8.50) in females and 2.01% (95% CI: 0.53-3.48) in males, and logistic regression showed a significantly higher odds of AI in females (OR=3.14, 95% CI: 1.33-7.45, p-value=0.009). The prevalence of AI was 2.59% (95% CI: 0.55-7.56) in the 18-19-year-old age group and 4.08% (95% CI: 0.09-8.07) in the 24-25-year-old group (p-value=0.848). The prevalence of AI among emmetropic, myopic, and hyperopic individuals was 3.74% (95% CI: 1.88-5.61), 4.44% (95% CI: 2.07-6.81), and 5.26% (95% CI: 4.79-16.32), respectively (p-value=0.869). In the multiple regression model, only gender showed significant relationship with AI (Odds ratio=3.14, 95% CI: 1.33-7.45; p-values=0.009).

CONCLUSION

The prevalence of AI in the present study is lower than the most prevalence rates reported in previous studies. In the present study, gender and AI showed a strong association, such that AI prevalence was significantly higher in females than males.

Accommodation function comparison following use of contact lens for orthokeratology and spectacle use in myopic children: a prospective controlled trial

AIM

To study effects of orthokeratology (Ortho-k) on accommodation function in myopic children.

METHODS

A prospective, non-randomized, case-control study was performed from September to October 2016. Eighty-three children with myopia were divided into two groups. One group was treated with the rigid contact lens for overnight Ortho-k, and the other was treated with single-vision spectacle lens (SVL). Accommodation function were assessed by accommodative amplitude (AA), accommodative sensitivity (AS), accommodative lag (Lag), negative relative accommodation (NRA), and positive relative accommodation (PRA) before and 1, 3, 6 and 12mo after treated.

RESULTS

Totally 72 myopic children were finished the follow-up: 37 in Ortho-k group and 35 in SVL group. Wearing time had a significant effect on AA, AS, Lag, and NRA of myopic children in two groups (all P<0.05). Meanwhile, there was an interaction effect between wearing time and wearing types (F_AA=5.3, F_AS=45.5, F_Lag=7.0, F_NRA=3.7, all P<0.05). However, the between-group difference of AA (F=0.1), AS (F=3.2), Lag (F=1.1), NRA (F=0.3), and PRA (F=0.1) showed no significance. AA, AS, NRA, Lag and PRA were improved significantly in Ortho-k group within 1 to 6mo after wearing.

CONCLUSION

Wearing Ortho-k can improve the accommodation function of myopic children, which might be one of the mechanisms for myopia control.