Monocular Accommodative Amplitude Research Articles

Reduced Monocular Accommodation Abilities with Laptop Usage Under Scotopic Ambient Illumination

Laptops are widely used even in dark scotopic rooms. This study compares monocular accommodation statuses with laptop usage under three illuminations. Thirty university students read on a laptop for 5 minutes under scotopic, mesopic, and photopic conditions. The monocular amplitude of accommodation, accommodation facility, and accommodation error are measured for each illumination. Repeated measure ANOVA shows a significant difference in the amplitude, facility, and error between different illuminations [F (1.49, 43.18) = 10.61, p<0.001], [F (1.65, 36.30) = 6.78, p=0.005] and [F (2, 56) = 3.65, p=0.032]. Scotopic illumination reduces monocular accommodation abilities with laptop usage.

Vergence and accommodation deficits in paediatric and adolescent patients during sub-acute and chronic phases of concussion recovery.

Visual function deficits have been reported in adolescents following concussion. We compared vergence and accommodation deficits in paediatric and adolescent patients at a tertiary medical centre in the sub-acute (15 days to 12 weeks) and chronic (12 weeks to 1 year) phases of concussion recovery. The study included patients aged 7 to <18 years seen between 2014 and 2021, who had a binocular vision (BV) examination conducted within 15 days and 1 year of their concussion injury. Included patients had to have 0.10 logMAR monocular best-corrected vision or better in both eyes and be wearing a habitual refractive correction. BV examinations at near included measurements of near point of convergence, convergence and divergence amplitudes, vergence facility, monocular accommodative amplitude and monocular accommodative facility. Vergence and accommodation deficits were diagnosed using established clinical criteria. Group differences were assessed using nonparametric statistics and ANCOVA modelling. A total of 259 patients were included with 111 in the sub-acute phase and 148 in the chronic phase of concussion recovery. There was no significant difference in the rates of vergence deficits between the two phases of concussion recovery (sub-acute = 48.6%; chronic = 49.3%). There was also no significant difference in the rates of accommodation deficits between the two phases of concussion recovery (sub-acute = 82.0%; chronic = 77.0%). Patients in both the sub-acute and chronic phases of concussion recovery exhibited a high frequency of vergence and accommodation deficits, with no significant differences between groups. Results indicate that patients exhibiting vision deficits in the sub-acute phase may not resolve without intervention, though a prospective, longitudinal study is required to test the hypothesis.

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

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. 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. 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. 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.

Comparison of Visual Symptom Frequency and Occupational Issues Between Patients With and Without Concussion.

Occupational therapy practitioners' knowledge of and advocacy for clients with visual symptoms postconcussion can have a considerable impact on recovery. To compare the frequency of vision symptoms and occupational performance deficits in a sample of participants with and without concussion. Cross-sectional study. Sports medicine clinic. Adolescents and adults with concussion (n = 20) and musculoskeletal injuries (n = 19). Measures included monocular amplitude of accommodation, near point of convergence, Binocular Vision Assessment (BVA) computerized screening for phoria, BVA computerized screening for fusional vergence, the Developmental Eye Movement Test, the Canadian Occupational Performance Measure, and the Convergence Insufficiency Symptom Survey-Concussion Version (CISS-CON). We found significant differences between participants with and without concussion using the CISS-CON (p = .001), positive fusional vergence (p = .02), and near point of convergence (p = .02). Participants with concussion scoring above cutoffs on multiple measures reported poorer performance (p = .005) and satisfaction (p = .004) with valued occupations. Concussion has a detrimental effect on vision and occupation, and occupational therapy practitioners are well-positioned to assess and address issues arising from this relationship. Plain-Language Summary: Vision symptoms commonly experienced after a concussion are associated with reduced occupational performance and satisfaction and can have a considerable impact on recovery. Occupational therapy assessment for clients with concussion should include screening for vision difficulties.

Comparison of proximal and minus lens autorefraction techniques to measure monocular accommodative amplitude.

This study provides a faster method for objectively measuring accommodative amplitude with an open-field autorefractor in a research setting. Objective measures of accommodative amplitude with an autorefractor take time because of the numerous stimulus demands tested. This study compares protocols using different amounts and types of demands to shorten the process. One hundred participants were recruited for four age bins (5 to 9, 10 to 14, 15 to 19, and 20 to 24 years) and monocular amplitude measured with an autorefractor using three protocols: proximal, proximal-lens (letter), and proximal-lens (picture). For proximal, measurements were taken as participants viewed a 0.9 mm "E" placed at 13 demands (40 to 3.3 cm = 2.5 to 30 D). The other protocols used a target (either the "E" or a detailed picture) placed at 33 and 12.5 cm followed by 12.5 cm with a series of lenses (-2, -4, and -5.5 D). Adjustments were made for lens effectivity for the three lens conditions, which were thus 9.6, 11.1, and 12.0 D for individuals without additional spectacle lenses. Accommodative amplitude was defined as the greatest response measured with each technique. One-way analysis of variance was used to compare group mean amplitudes across protocols and differences between letter protocols by age bin. Amplitudes were significantly different between protocols (p < 0.001), with proximal having higher amplitudes (mean ± standard deviation, 8.04 ± 1.70 D) compared with both proximal-lens protocols (letter, 7.48 ± 1.42 D; picture, 7.43 ± 1.42 D) by post hoc Tukey analysis. Differences in amplitude between the proximal and proximal-lens (letter) protocol were different by age group (p = 0 .003), with the youngest group having larger differences (1.14 ± 1.58 D) than the oldest groups (0.17 ± 0.58 and 0.29 ± 0.48 D, respectively) by post hoc Tukey analysis. The proximal-lens protocols took less time and identified the maximum accommodative amplitude in participants aged 15 to 24 years; however, they may underestimate true amplitude in younger children.

Do monocular myopia children need to wear glasses? Effects of monocular myopia on visual function and binocular balance.

This study aims to compare the binocular visual functions and balance among monocular myopic adolescents and adults and binocular low myopic adolescents and explore whether monocular myopia requires glasses. A total of 106 patients participated in this study. All patients were divided into three groups: the monocular myopia children group (Group 1 = 41 patients), the monocular myopia adult group (Group 2 = 26 patients) and the binocular low myopia children group (Group 3 = 39 patients). The refractive parameters, accommodation, stereopsis, and binocular balance were compared. The binocular refractive difference in Group 1, Group 2, and Group 3 was -1.37 ± 0.93, -1.94 ± 0.91, and -0.32 ± 0.27 D, respectively. Moreover, uncorrected visual acuity (UCVA), spherical equivalent (SE) and monocular accommodative amplitude (AA) between myopic and emmetropic eyes in Group 1 and Group 2 were significantly different (all P < 0.05). There was a significant difference in the accommodative facility (AF) between myopic and emmetropic eyes in Group 2 (t = 2.131, P = 0.043). Furthermore, significant differences were found in monocular AA (t = 6.879, P < 0.001), binocular AA (t = 5.043, P < 0.001) and binocular AF (t = -3.074, P = 0.003) between Group 1 and Group 2. The normal ratio of stereopsis according to the random dots test in Group 1 was higher than in Group 2 (χ2 = 14.596, P < 0.001). The normal ratio of dynamic stereopsis in Group 1 was lower than in Group 3 (χ2 = 13.281, P < 0.001). The normal signal-to-noise ratio of the binocular balance point in Group 1 was lower than Group 3 (χ2 = 4.755, P = 0.029). First, monocular myopia could lead to accommodative dysfunction and unbalanced input of binocular visual signals, resulting in myopia progression. Second, monocular myopia may also be accompanied by stereopsis dysfunction, and long-term uncorrected monocular myopia may worsen stereopsis acuity in adulthood. In addition, patients with monocular myopia could exhibit stereopsis dysfunction at an early stage. Therefore, children with monocular myopia must wear glasses to restore binocular balance and visual functions, thereby delaying myopia progression.

Establishing Normative Values for Amplitude of Accommodation and Accommodative Facility among University Students in Malawi

Aim: The study aimed to examine the distribution of Accommodative Facility (AF) and Amplitude of Accommodation (AA) and compare the findings with established guidelines.&#x0D; Place and Duration of Study: Mzuzu University, Malawi. Between May and July 2022.&#x0D; Methods: This cross-sectional study was conducted among students at Mzuzu university in Malawi. We recruited 77 students using a stratified random sampling technique. The participants' age ranged from 16 to 35 years of age. We measured AA using the push-up method while AF was measured using +/- 1.50 Diopters (D) flippers. Both techniques utilized black reading material on white background held at 40 centimeters (cm). Next, we measured the accommodation facility by counting the number of Cycles per Minute (c/m). We utilized the Pearson correlation test and the One-way ANOVA where appropriate. The value of p&lt; 0.05 was considered statistically significant. &#x0D; Results: The participants comprised 44 (57.1%) males and 33 (42.9%) females. Monocular AA was 10.04D (SD=2.71) and Binocular AA was 10.51 (3.641). The difference was statistically significant (p=0.04). While Monocular AF and Binocular AF were 9 c/m (SD= SD=1.84) and 8.96 (SD=1.539) respectively but the difference was non-significant (p=0.868). AF and AA were not significantly different between males and females. All the parameters decreased with age. The measured AA was significantly higher than using Hofstetter’s formula.&#x0D; Conclusion: The study provides a cut-off value for practitioners diagnosing Accommodation anomalies. However, indices in the study differ from the well-established guidelines hence practitioners should endeavor to perform the clinical assessment instead of relying on equations.

Near work symptoms and measures of accommodation in children

ABSTRACT Clinical relevance Some children experience significant symptoms while doing near work, and accommodative deficits can be a contributory factor. However, studies investigating near work symptoms in children are sparse. Background To investigate the association between clinical and objective measures of accommodation and near point symptoms. Methods Twelve asymptomatic and 14 symptomatic children (mean age = 11.1 and 11.8 years, respectively) based on their Convergence Insufficiency Symptom Survey scores participated in the study. The clinical measures of accommodation were monocular amplitude of accommodation, monocular accommodative facility, and monocular estimation method. Objective measurements of the accommodative stimulus response function were recorded with a WAM-5500 autorefractor for two consecutive minutes at five viewing distances (0.33, 2, 3, 4, and 5 Dioptres [D]). Accommodative findings were compared between the groups using the Mann–Whitney U-tests. Spearman’s rank correlation coefficient was used to assess the association between symptoms and clinical and objective measures of accommodation. Results The mean CISS scores were 32.8 and 7.3 for the symptomatic and asymptomatic groups, respectively (p = <0.001). The symptomatic group showed a reduced accommodative functions compared to the asymptomatic group (p = 0.002 for accommodative facility, p = 0.04 for accommodative amplitude, p = 0.029 and 0.01 for objective measures of accommodation at 4D and 5D viewing distance, respectively). Clinical tests of accommodative amplitude and facility (correlation coefficient = −0.407 and −0.54, respectively) showed the highest correlation with the CISS scores, compared to the objective measures of accommodation. Conclusion Clinical tests of accommodation showed a greater association with symptoms than objective measures of accommodation in children aged 8–16 years. In children presenting with visual discomfort symptoms, measurement of accommodative amplitude and facility should be considered.

Virtual reality-based vision therapy versus OBVAT in the treatment of convergence insufficiency, accommodative dysfunction: a pilot randomized controlled trial

BackgroundVirtual reality is being increasingly applied in vision therapy. However, the differences in effectiveness, optimal treatment cycle, and prognosis between virtual reality-based vision therapy and traditional therapies remain unknown. The purpose of this study was to compare the effectiveness of virtual reality-based vision therapy and office-based vergence/accommodative therapy in young adults with convergence insufficiency or accommodative dysfunction.MethodsThe patients were randomly assigned to either the virtual reality-based vision therapy group or the office-based vergence/accommodative therapy group. The vision therapy lasted 12 weeks (1 h/week) in both groups. Binocular visual functions (vergence and accommodation) were measured and a subjective questionnaire-based assessment was performed at baseline and after 6 and 12 weeks of therapy.ResultsIn total, 33 patients with convergence insufficiency and 30 with accommodative dysfunction completed the study. After 12 weeks of treatment for convergence insufficiency, the Convergence Insufficiency Symptom Survey score (F2,31 = 13.704, P < 0.001), near point of convergence (F2,31 = 21.774, P < 0.001), positive fusional vergence (F2,31 = 71.766, P < 0.001), and near horizontal phoria (F2,31 = 16.482, P < 0.001) improved significantly in both groups. Moreover, the monocular accommodative amplitude (F2,25 = 22.154, P < 0.001) and monocular accommodative facility (F2,25 = 86.164, P < 0.001) improved significantly in both groups after 12 weeks of treatment. A statistically significant difference was observed in monocular accommodative facility (F1,25 = 8.140, P = 0.009) between the two groups, but not in other vergence and accommodative functions (0.098 < P < 0.687).ConclusionVirtual reality-based vision therapy significantly improved binocular vision functions and symptoms in patients with convergence insufficiency and accommodative dysfunction, thereby suggesting its effectiveness as a new optional or additional treatment for young adults with these conditions.Trial registrationThis study was registered at the Chinese Clinical Trials Registry on 16/04/2019 (identifier: ChiCTR1900022556).

Does coexisting accommodative dysfunction impact clinical convergence measures, symptoms and treatment success for symptomatic convergence insufficiency in children?

To determine whether coexisting accommodative dysfunction in children with symptomatic convergence insufficiency (CI) impacts presenting clinical convergence measures, symptoms and treatment success for CI. Secondary data analyses of monocular accommodative amplitude (AA; push-up method), monocular accommodative facility (AF; ±2.00D lens flippers) and symptoms (CI Symptom Survey [CISS]) in children with symptomatic CI from the Convergence Insufficiency Treatment Trial (N=218) and CITT-Attention and Reading Trial (N=302) were conducted. Decreased AA was defined as more than 2D below the minimum expected amplitude for age (15 - ¼ age); those with AA<5D were excluded. Decreased AF was defined as <6 cycles per minute. Mean near point of convergence (NPC), near positive fusional vergence (PFV) and symptoms (CISS) were compared between those with and without accommodative dysfunction using analysis of variance and independent samples t-testing. Logistic regression was used to compare the effect of baseline accommodative function on treatment success [defined using a composite of improvements in: (1) clinical convergence measures and symptoms (NPC, PFV and CISS scores) or (2) solely convergence measures (NPC and PFV)]. Accommodative dysfunction was common in children with symptomatic CI (55% had decreased AA; 34% had decreased AF). NPC was significantly worse in those with decreased AA (mean difference=6.1cm; p<0.001). Mean baseline CISS scores were slightly worse in children with coexisting accommodative dysfunction (decreased AA or AF) (30.2 points) than those with normal accommodation (26.9 points) (mean difference=3.3 points; p<0.001). Neither baseline accommodative function (p≥0.12 for all) nor interaction of baseline accommodative function and treatment (p≥0.50) were related to treatment success based on the two composite outcomes. A coexisting accommodative dysfunction in children with symptomatic CI is associated with worse NPC, but it does not impact the severity of symptoms in a clinically meaningful way. Concurrent accommodative dysfunction does not impact treatment response for CI.

Study on Binocular Accommodative Function in Children With Different Types of Intermittent Exotropia.

Objective: This study aims to investigate the monocular and binocular accommodative amplitude (AMP) and accommodative function (AF) in children with different types of intermittent exotropia (IXT).Methods: A total of 40 children with IXT were enrolled in the study. Monocular and binocular AMP and AF were measured using the modified approach method and the ±2D flip method, and the differences between the fixing and non-fixing eyes of non-strabismic children and children with different types of IXT were compared.Results: The AMP of the fixing eyes of children with IXT was lower than that of their non-fixing eyes (p = 0.007). Conversely, the AF was higher in the fixing eyes than in the non-fixing eyes (p < 0.001). The AMPs of each group of children with IXT were lower than those of the control group, while the AMP of the group with convergence insufficiency was lower than that of the other two groups with IXT. In addition, the AF of the group with convergence insufficiency was lower than that of the group with basic exotropia and the control group (p < 0.05).Conclusion: There is a difference in accommodation between the fixing and non-fixing eyes of children with IXT, and the degree of variation depends on the type of IXT. Moreover, the binocular accommodative function of children with IXT is lower than that of non-strabismic children.

The effect of extended depth of focus contact lenses on the accommodation of presbyopic eyes

Objective: To evaluate the effect of extended depth of focus contact lenses on the accommodation of presbyopic eyes. Methods: It was a double-blind randomized controlled trial. Thirty eyes of 30 emmetropic volunteers (15 males, 15 females) who were staff or family members of Hainan Eye Hospital, aged (49.6±4.5) years, were selected. Non-dominant eyes were fitted with soft contact lenses with an extended depth of field. The subjects and examiners were double-blind. Visual acuities of the subjects were examined at 5 m, 40 cm and 60 cm distance before and after the contact lens wear. Meanwhile, the monocular accommodative amplitude, monocular accommodative facility (±1.00 D), accommodative response, binocular positive/negative relative accommodation and accommodation convergence/accommodation at 40 cm distance were measured. The data were analyzed by paired t test and Wilcoxon signed rank test before and after the contact lens wear, and a P value less than 0.05 was considered statistically significant. Results: Before and after the contact lens wear, the visual acuity at 40 cm was 4.59±0.14 and 4.69±0.10, and the difference was statistically significant (t=4.16, P<0.01). The visual acuity at 60 cm was 4.74±0.10 and 4.74±0.12, and the difference had no statistical significance (t=0.626, P>0.05). The distance visual acuity was 5.00±0.06 and 4.96±0.06, and the difference was statistically significant (t=3.89, P<0.01). The monocular accommodative amplitude was significantly improved from (3.26±0.26) D to (4.00±0.51) D (t=7.59, P<0.01). The monocular accommodative facility was also significantly improved from (2.67±1.60) cyc/min to (3.53±1.87) cyc/min (t=2.17, P<0.05). There was no statistically significant difference in the positive and negative relative accommodation (t=1.90, 0.66; P>0.05). The accommodation convergence/accommodation and adjustment lag had no statistical significance (Z=0.83, 0.11; P>0.05). Conclusion: Wearing contact lenses with an extended depth of field can improve the near vision and accommodation of presbyopes (Chin J Ophthalmol, 2021, 57:292-296).

Frequency of oculomotor disorders in adolescents 11 to 17 years of age with concussion, 4 to 12 weeks post injury

The purpose of the study was to determine the frequency of vision diagnoses after concussion in adolescents and evaluate the sensitivity and specificity of physician-administered screening for detecting convergence and accommodative disorders post-concussion. We enrolled participants 11 to 17 years old, assessed 4 to 12 weeks following a diagnosed concussion. During the initial concussion examination, a sports medicine physician measured the near point of convergence (NPC), monocular accommodative amplitude (AA), and symptoms using the Convergence Insufficiency Symptom Survey (CISS). A comprehensive oculomotor evaluation was performed by an optometrist. One hundred and thirteen adolescents were enrolled, with a mean age of 15.2 years. Seventy-nine of the 113 (70%) participants had at least one oculomotor diagnosis after concussion, with the most common problems being vergence disorders (60%) and accommodative disorders (57%). The most common vergence disorder was convergence insufficiency (35%). Among accommodative disorders, the most common problem was accommodative insufficiency (35%). In all, 47% of the participants had more than one oculomotor diagnosis following concussion. The sensitivity of physician screening using measures of NPC, AA, and CISS for detecting convergence and accommodative insufficiency was 63%, 43%, 48%, respectively. The results of this study provide additional evidence that vision problems are common in adolescents with persistent concussion symptoms in the sub-acute phase 4 to 12 weeks post-concussion, and current physician screening methods using the NPC, AA, or the CISS underperform. Thus, it is prudent that adolescents with post-concussion symptoms lasting more than 4 weeks post injury receive a comprehensive oculomotor examination.

Accommodation changes after strabismus surgery due to anterior ciliary vessel disruption.

To evaluate monocular accommodation changes after strabismus surgery with and without anterior ciliary vessel preservation. Sixty patients with horizontal concomitant strabismus who were scheduled to undergo monocular strabismus surgeries were randomly divided into two groups: A (without anterior ciliary vessel preservation) and B (with anterior ciliary vessel preservation). Group A was further divided into groups A1 (surgical eyes without anterior ciliary vessel preservation) and A2 (corresponding nonsurgical eyes). Group B was further divided into groups B1 (surgical eyes with anterior ciliary vessel preservation) and B2 (corresponding nonsurgical eyes). Monocular accommodative amplitude (AA) and accommodative facility (AF) were evaluated before and 1day after the surgery to assess accommodation. In groups A2, B1, and B2, the AA and AF values showed no significant difference preoperatively or postoperatively. However, compared with preoperative values, both the postoperative AA and AF values were significantly reduced in group A1. Strabismus surgery without anterior ciliary vessel preservation reduces monocular accommodation, whereas strabismus surgery with anterior ciliary vessel preservation protects accommodation.

Feasibility of optical quality analysis system for the objective assessment of accommodation insufficiency: a phase 1 study

PurposeTo assess differences in a new objective metric obtained with a double-pass technique between a group with accommodation insufficiency (AI) and a control group and to explore the diagnostic capabilities of this new tool in comparison to conventional procedures. MethodsRetrospective cross-sectional case-control phase 1 study. Two groups with ages ranging from 8 to 18 years were recruited: AI and control group. The diagnostic criterion of AI was based on monocular accommodative amplitude (AA), 2 D below Hofstetter’s calculation for minimum AA, and monocular accommodative facility (MAF), failing with minus lens and cut-off at ≤ 6 cycles per minute. Accommodative response with a double pass device (HD Analyzer, Visiometrics) was measured, performing an evaluation from +1.00 D to −3.50D (−0.5D steps), offering the width of the profile at 50% (WP) in minutes of arc. ResultsDifferences were found between groups for the AA, MAF and MEM retinoscopy (p < 0.0001, p < 0.001, p = 0.037). The discriminative capacity of MEM retinoscopy for AI diagnosis was significant and the cut-off that maximized the sensitivity and specificity was > 0.5 D. Considering WP 50% in different points, the discriminative AI diagnosis capacities for the points of 2.0 D and 2.50 D were significant (ROC-AUC 0.78; p = 0.03 and p = 0.02). ConclusionsDouble-pass system metric differed between patients with AI and control group, therefore the aim of a Phase I study was achieved. Further steps with higher sample sizes are required to evidence if the system really provides any advantage versus conventional methods in the diagnosis of AI.

Neurosensory Screening and Symptom Provocation in Pediatric Mild Traumatic Brain Injury.

To evaluate diagnostic/prognostic implications of neurosensory testing during the subacute stage in patients with pediatric mild traumatic brain injury (pmTBI). Recruitment from pediatric emergency department and urgent care clinics, assessment in a controlled environment. In total, 146 pmTBI patients evaluated 7.4 ± 2.3 days and approximately 4 months postinjury; 104 age/sex-matched healthy controls (HCs) at equivalent time points. Prospective cohort study. Neurosensory examination based on sequence of 10 established tests of vestibular-ocular, oculomotor, vestibulospinal, and visual functioning. The amount of symptom provocation (positive change from pretest symptomatology) was significantly increased in pmTBI relative to HCs on every subtest 1 week postinjury, as were deficits in monocular accommodative amplitude and King-Devick Test errors. However, symptom provocation did not meaningfully alter diagnostic sensitivity/specificity relative to more easily obtained pretest symptom ratings. Evidence of clinically significant symptom provocation 1 week postinjury improved sensitivity (Δ = +12.9%) of identifying patients with persistent postconcussive symptoms 4 months postinjury on an independent symptom measure. The diagnostic sensitivity/specificity of neurosensory testing in acutely concussed youth may be limited at 1 week postinjury as a function of natural recovery occurring in most emergency department cohorts. Neurosensory screening may have greater utility for identifying patients who experience delayed recovery.

The role of clinical diagnosis criteria on the frequency of accommodative insufficiency.

To estimate and compare the frequency of accommodative insufficiency (AI) within the same clinical population sample depending on the type of clinical criteria used for diagnosis. Comparing the frequency within the same population would help to minimize bias due to sampling or methodological variability. Retrospective study of 205 medical records of symptomatic subjects free of any organic cause and symptoms persisting despite optical compensation evaluated. Based on the most commonly clinical diagnostics criteria found in the literature, four diagnostics criteria were established for AI (I, II, III and IV) based on subjective accommodative tests: monocular accommodative amplitude two or more diopters below Hofstetter's minimum value [15-(0.25×age)] (I, II, III, IV); failing monocular accommodative facility with minus lens, establishing the cut-off in 0 cycles per minute (cpm) (I) and in 6 cpm (II, III); failing binocular accommodative facility with minus lens, establishing the cut-off in 0 cpm (I) and in 3 cpm (II). The proportion of AI (95%CI) for criteria I, II, III and IV were 1.95% (0.04%-3.86%), 2.93% (0.31%-4.57%), 6.34% (1.90%-7.85%) and 41.95% (35.14%-48.76%) respectively, with a statistically significant difference shown between these values (χ2 =226.7, P<0.001). A pairwise multiple comparison revealed that the proportion of AI detected for criterion IV was significantly greater than the proportion for the rest of the criteria (P-adjusted<0.05 in all cases). The prevalence of cases of AI within the same clinical population varies with the clinical diagnostic criteria selected. The variation is statistically significant when considering the monocular accommodative amplitude as the only clinical diagnostic sign.

Comparison of the amplitude of accommodation determined subjectively and objectively in South African university students

Background: Historically, two clinical methods have been used for measuring the amplitude of accommodation, which are the push-up and minus lens methods. However, it has been documented that the push-up method overestimates amplitude of accommodation, while the minus lens method underestimates it.Aim: The purpose of this study was to compare subjective and objective procedures for determining the monocular amplitude of accommodation in young optometry students.Setting: The study was conducted in the optometry clinic at the university.Methods: Amplitude of accommodation was measured on 45 optometry students (17 males and 28 females, whose ages ranged from 21 to 27 years) using the push-up, push-down, minus lens, modified dynamic retinoscopy and Pascal dynamic retinoscopy methods. Data were collected by three different examiners in this study. One examiner measured all the subjective tests, while another examiner measured the modified dynamic retinoscopy. The third examiner measured the Pascal heterodynamic retinoscopy.Results: The highest amplitude of accommodation was obtained using the push-up method (10.23 ± 1.67 D), while the minus lens method gave the lowest subjective finding (8.43 ± 1.68 D). However, the subjective methods generally produced comparable results. Both retinoscopic methods showed the lowest mean amplitude of accommodation of approximately 6.50 ± 1.40 D. However, there was a high correlation between the various methods.Conclusion: The push-up and push-down methods overestimate the true amplitude of accommodation because of the relative magnification, while the minus lens method creates an abnormal viewing environment in which the target is stationary but the stimulus becomes increasingly minified. Subjective amplitude of accommodation is an inadequate measure to assess any true accommodation because it fails to differentiate between passive depth of focus and an active accommodative power change in the eye. Therefore, subjective measurement of the amplitude of accommodation may suggest that accommodation is present when it is not. Further research is needed to further validate dynamic retinoscopy as the optimal or best possible routine clinical method to assess the true amplitude of accommodation.

Change Amplitude of Accommodation and Lens Adaptation after Adding Spherical Lens

Purpose: To evaluate the lens adaptation by comparing the changes of amplitude of accommodation against adding power of (±) spherical lenses. Methods: 51 subjects (26 men and 25 women) aged 21.76±1.76 years participated for this study. Refractive errors of subjects were fully corrected, S+1.00 D, S+2.00 D, S+3.00 D, S-1.00 D, S-2.00 D, and S-3.00 D were added in the order on each eye, and after that, monocular amplitude of accommodation (AA) was measured using a push-up method at 0, 15, and 30 minutes for each subject. The values were statistically compared to those of fully corrected state and the change level of AA between before and after adding lens was calculated as a relative ratio to the each spherical diopters added. Results: After S+1.00 D, S+2.00 D, or S+3.00 D was added, the AA was significantly (p<0.001) higher than that of fully corrected state. However, the change level of the AA was by 55~68% of the adding spherical diopter. After S-1.00 D, S-2.00 D, or S-3.00 D was added, the AA was significantly (p<0.001) lower than that of fully corrected state. The change level of the AA was by 72~105% of the adding spherical diopter. Conclusions: When prescribing a spherical lens related to accommodative functions, clinical practitioners have to consider that the change of AA is mostly smaller than the power of added spherical lens because of lens adaptation.

Prevalence of Oculomotor Dysfunction in Healthy Athletes Preseason: Implications for Concussion in Sport

Background: Measures of oculomotor function are becoming more frequently employed as part of comprehensive concussion assessments. However, performances on many of these oculomotor measures have not been examined in a healthy athletic cohort. The purpose of this study was to characterize performance of university level athletes on a battery of oculomotor tests and identify any potential influence of gender and history of concussion. Methods: 259 healthy university level athletes (males, n = 150; females, n = 109) completed an oculomotor screening battery prior to the start of their competitive season. The battery assessed stereopsis, visual acuity, monocular amplitude of accommodation, near point of convergence, monocular and binocular accommodative facility, vergence facility, positive and negative fusional vergence, and saccades. Athletes also completed the Convergence Insufficiency Symptom Survey (CISS). Results: Three oculomotor tests (stereopsis, convergence, saccades) showed significant differences between male and female athletes at P&lt;0.05, uncorrected. A high percentage of athletes were identified as having oculomotor deficiencies including abnormal acuity (34.2%), vergence infacility (28.6%), abnormal horizontal saccades (21.7%) and accommodative infacility (18.7%). Convergence insufficiency differed by method of assessment, ranging from 11.0-15.7%. Conclusion: A significant proportion of healthy athletes displayed abnormal performance across a variety of oculomotor indices. A history of lifetime concussion (i.e., greater than 12 months prior to study) did not significantly influence oculomotor test performance. Clinicians should be aware of such differences and potential implications associated with postconcussion evaluations.