Constructing country-specific quality-of-life item banks for adults with amblyopia and strabismus in Australia and India.

CLINICAL RELEVANCE: Understanding the quality-of-life (QoL) impacts of amblyopia and strabismus from the perspectives of patients using validated tools would enable eye care practitioners to provide better clinical management. BACKGROUND: Item banks are advanced patient reported outcome measures with several advantages over traditional QoL assessment. This paper describes the development of amblyopia and strabismus-specific QoL item banks for two distinct country settings: Australia (high-income) and India (low-middle income) and examines the unique QoL issues. METHODS: Using a bottom-up systematic approach, the content for the item banks was identified from three sources: existing self-report amblyopia and strabismus questionnaires (n = 22), qualitative literature (n = 5) and prospective qualitative studies in Australia (n = 49) and India (n = 30). The initial item pool underwent item evaluation, construction, and pre-testing to form optimal sets of representative items. The Indian item pools were first developed in English and translated into Hindi and Tamil using a rigorous translation protocol. The differences in QoL experiences that emanated from the qualitative studies and the number of common and unique items in the final item pools were compared. RESULTS: The final Australian and Indian item pools comprised 312 and 277 items, respectively, covering 11 QoL domains. Two hundred and sixty items (79%) were common to both countries, and 21% were unique. Of the 11 domains, except for activity limitation (64.5%), visual symptoms (73.3%) and emotional impact (75.5%) domains, all other domains had over 80% of items common to both countries. The unique items can be attributed to differences in QoL experiences, individual perspectives, culture, lifestyle, country setting and health systems. CONCLUSION: Amblyopia has a multifaceted impact on QoL irrespective of the country settings. Despite a huge overlap in QoL impacts between Australia and India, both countries had unique issues, especially activity limitations. The study developed comprehensive, country-specific item pools for Australia and India.

Fine visuomotor skills in amblyopia: a systematic review and meta-analysis.

BACKGROUND: Amblyopia is characterised by reduced visual acuity, poor binocular sensory fusion, and impaired or absent stereoacuity. Understanding the extent to which amblyopia affects everyday task performance is important to quantifying the disease burden of amblyopia and can assist clinicians to understand patients' likely functional capability. METHODS: A systematic literature search identified published studies comparing fine visuomotor performance in either children or adults with amblyopia and those with normal binocular vision. The included studies (22 studies involving 835 amblyopes and 561 controls) reported results of self-perception patient reported outcome measures, tests of motor proficiency and video recorded reaching and grasping. The outcomes of 17 studies were grouped into four meta-analyses, with pooled results reported as standardised mean difference (SMD) with corresponding 95% CI. RESULTS: Regardless of the cause of amblyopia (anisometropia, strabismus, mixed, deprivation), significant reduction in self-perception of physical competence and athletic competence (SMD=-0.74, 95% CI -1.23 to -0.25, p=0.003); fine motor skills scores (SMD=-0.86, 95% CI -1.27 to -0.45, p<0.0001); speed of visually guided reaching and grasping movements (SMD=0.86, 95% CI 0.65 to 1.08, p<0.00001); and precision of temporal eye-hand coordination (SMD=0.75, 95% CI 0.26 to 1.25, p=0.003) occurred in amblyopes compared with those with normal visual development. CONCLUSION: Reports of the impact of amblyopia on fine motor skills performance find poorer outcomes in participants with amblyopia compared with those with normal vision development. Consistency in the outcome measure used to assess the functional impact of amblyopia would be valuable for future studies.

Discrimination of paediatric acuity test optotypes by 6-year-old children.

PURPOSE: To compare the discrimination performance of 6-year-old children for optotypes from six paediatric visual acuity tests and to fit Luce's Biased Choice Model to the data to estimate the relative similarities and bias for each optotype. METHODS: Full data sets were collected from 20 typically developing 6-year-olds who had passed a vision screening. They were presented with single optotypes labelled 6/12 at a distance of 9 m and were asked to identify the optotype using a matching task containing all optotypes from the relevant test. The data were combined to form a confusion matrix for each test and a biased choice model was fitted to the data. RESULTS: Median correct performance varied from 40% to 100% across optotypes, with the HOTV test having the highest values. Estimates of the similarity of each pair of optotypes indicated equal values for all pairs in the Landolt C, HOTV, Lea numbers and Tumbling E tests. The values differed for the picture tests, that is Lea Symbols and Allen figures. The estimates of bias for each individual optotype also indicated different values with the picture tests. CONCLUSIONS: Previous studies of the threshold acuity of young children and adults have indicated differences in acuity estimates across paediatric tests. A recognition acuity task typically requires resolving the difference information between optotypes. The performance of the 6-year-olds here reveals variance in similarity and bias values for picture tests, particularly for the Allen figures when compared with the Lea Symbols. Ideally, this analysis should be performed when designing new tests, and these results motivate progression from the use of current picture tests to well calibrated letter or number tests at the earliest possible age.

The effects of optically and digitally simulated aniseikonia on stereopsis.

PURPOSE: To simulate both lens-induced and screen-induced aniseikonia, and to assess its influence on stereopsis. Additionally, to determine if screen-based size differences could neutralise the effects of lens-induced aniseikonia. METHOD: A four-circle (4-C) paradigm was developed, where one circle appears in front or behind the others because of crossed or uncrossed disparity. This stereotest was used for three investigations: (1) Comparison with the McGill modified random dot stereogram (RDS), with anisometropia introduced with +2 D spheres and cylinders, and with aniseikonia introduced with 6% overall and 6% meridional (×180, ×90) magnifiers before the right eye; (2) Comparison of lens-induced and screen-induced 6% overall and meridional magnifications and (3) Determining if lens and screen effects neutralised, by opposing 6% lens-induced magnification to the right eye with screen-inducements of either 6% left eye magnification or 6% right eye minification. A pilot study of the effect of masking versus not masking the surround was also conducted. RESULTS: The 4-C test gave higher stereo-thresholds than the RDS test by 0.5 ± 0.2 log units across both anisometropic and aniseikonic conditions. However, variations in power, meridian and magnification affected the two tests similarly. The pilot study indicated that surround masking improved neutralisation of screen and lens effects. With masking, lens-induced and screen-induced magnifications increased stereo-thresholds similarly. With lens and screen effects opposed, for most participants stereo-thresholds returned to baseline for overall and ×180 magnifications, but not for ×90 magnification. Only three of seven participants showed good compensation for ×90 magnification. CONCLUSIONS: Effects of lens-induced aniseikonia on stereopsis cannot always be successfully simulated with a screen-based method. The ability to neutralise refractive aniseikonia using a computer-based method, which is the basis of digital clinical measurement, was reasonably successful for overall and ×180 meridional aniseikonia, but not very successful for ×90 aniseikonia.

Does non-strabismic amblyopia affect the quality of life of adults? Findings from a qualitative study.

PURPOSE: While much is known about the psychosocial impacts of strabismus, little is known about the effects of non-strabismic amblyopia on quality of life (QoL). The aim of this study was to explore the long-term impacts of anisometropic amblyopia. METHODS: A phenomenological qualitative investigation was carried out on a sample of adults with anisometropic amblyopia. Subjects participated in in-depth telephone interviews and described how their eye condition affected different aspects of their life. The interviews were audio-recorded, transcribed verbatim and analysed iteratively to form emergent themes. RESULTS: Sixteen participants took part in the study (median age: 21.5 years; range: 18-36 years; 11 male and 5 female). Six themes emerged: (1) symptoms experienced by participants, (2) concerns and apprehensions, (3) emotional impacts, (4) activity limitations, (5) hassle and inconveniences and (6) economic and career implications. Symptoms reported by participants ranged from glare to difficulty concentrating. They were extremely concerned about the safety of their better eye and lived with several doubts and anxieties. Negative emotions such as grief and disappointment due to eye care negligence in childhood was apparent. Guilt and regretful feelings were present in those who did not comply with past treatment. Participants expressed several limitations in driving, reading, mobility (e.g., using stairs) and tasks requiring high resolution. Reported inconveniences associated with coping with their eye condition included having to travel across the country in search of a cure for their amblyopia. Economic impacts ranged from costs associated with accessing eye care and management to career choices being compromised. CONCLUSION: Lived experiences of people with anisometropic amblyopia indicate that the QoL impacts are multifaceted and substantial, even in the absence of strabismus. The results have the potential to influence patient-practitioner relationship by opening newer horizons to communication and care while managing adult amblyopes.

Visual rehabilitation using video game stimulation for Stargardt disease.

BACKGROUND: Stargardt disease, a common form of heredomacular degeneration, leads to severe vision loss. Video game play can act as a positive biofeedback to reinforce visual rehabilitation and fixation training. It can potentially lead to visual improvement. This study was done to explore the possibility of visual improvement using video game stimulation for visual rehabilitation in Stargardt disease. METHODS: We evaluated eight patients with Stargardt disease who had nonatrophic retina surrounding the area of degeneration at the macula. They underwent extensive baseline testing to determine their Snellen visual acuity, pattern visual evoked potentials, retinal sensitivity, and fixation analysis with microperimetry, electroretinography, fundus photography, optical coherence tomography, and autofluorescence. They were given 40 h of training with video game play and re-evaluated on all the tests. RESULTS: They showed both subjective and objective evidence of improvement in visual functions and vision-related tasks. Visual acuity (from 0.77 ± 0.29 to 0.71 ± 0.32 logMAR, p = 0.027), contrast sensitivity (from 1.28 ± 0.25 to 1.46 ± 0.17, p = 0.002), and fixation stability (log of bivariate contour ellipse area from 6.67 ± 0.52 to 5.85 ± 0.84, p = 0.022) improved significantly. The retinal sensitivity improved by 0.47 ± 3.39 dB (p = 0.67). Stereopsis and pattern visual evoked potentials showed improvement. A low vision questionnaire documented subjective improvement. CONCLUSION: Visual stimulation by video game play can result in improvement in visual acuity, fixation pattern, and retinal sensitivity with improvement in vision-related tasks. It can serve as a simple rehabilitatory technique for patients with central vision loss due to Stargardt disease.

The minimum test battery to screen for binocular vision anomalies: report 3 of the BAND study.

PURPOSE: This study aims to report the minimum test battery needed to screen non-strabismic binocular vision anomalies (NSBVAs) in a community set-up. When large numbers are to be screened we aim to identify the most useful test battery when there is no opportunity for a more comprehensive and time-consuming clinical examination. METHODS: The prevalence estimates and normative data for binocular vision parameters were estimated from the Binocular Vision Anomalies and Normative Data (BAND) study, following which cut-off estimates and receiver operating characteristic curves to identify the minimum test battery have been plotted. In the receiver operating characteristic phase of the study, children between nine and 17 years of age were screened in two schools in the rural arm using the minimum test battery, and the prevalence estimates with the minimum test battery were found. RESULTS: Receiver operating characteristic analyses revealed that near point of convergence with penlight and red filter (> 7.5 cm), monocular accommodative facility (< 10 cycles per minute), and the difference between near and distance phoria (> 1.25 prism dioptres) were significant factors with cut-off values for best sensitivity and specificity. This minimum test battery was applied to a cohort of 305 children. The mean (standard deviation) age of the subjects was 12.7 (two) years with 121 males and 184 females. Using the minimum battery of tests obtained through the receiver operating characteristic analyses, the prevalence of NSBVAs was found to be 26 per cent. Near point of convergence with penlight and red filter > 10 cm was found to have the highest sensitivity (80 per cent) and specificity (73 per cent) for the diagnosis of convergence insufficiency. For the diagnosis of accommodative infacility, monocular accommodative facility with a cut-off of less than seven cycles per minute was the best predictor for screening (92 per cent sensitivity and 90 per cent specificity). CONCLUSION: The minimum test battery of near point of convergence with penlight and red filter, difference between distance and near phoria, and monocular accommodative facility yield good sensitivity and specificity for diagnosis of NSBVAs in a community set-up.

Prevalence of non-strabismic anomalies of binocular vision in Tamil Nadu: report 2 of BAND study.

BACKGROUND: Population-based studies on the prevalence of non-strabismic anomalies of binocular vision in ethnic Indians are more than two decades old. Based on indigenous normative data, the BAND (Binocular Vision Anomalies and Normative Data) study aims to report the prevalence of non-strabismic anomalies of binocular vision among school children in rural and urban Tamil Nadu. METHODS: This population-based, cross-sectional study was designed to estimate the prevalence of non-strabismic anomalies of binocular vision in the rural and urban population of Tamil Nadu. In four schools, two each in rural and urban arms, 920 children in the age range of seven to 17 years were included in the study. Comprehensive binocular vision assessment was done for all children including evaluation of vergence and accommodative systems. In the first phase of the study, normative data of parameters of binocular vision were assessed followed by prevalence estimates of non-strabismic anomalies of binocular vision. RESULTS: The mean and standard deviation of the age of the sample were 12.7 ± 2.7 years. The prevalence of non-strabismic anomalies of binocular vision in the urban and rural arms was found to be 31.5 and 29.6 per cent, respectively. Convergence insufficiency was the most prevalent (16.5 and 17.6 per cent in the urban and rural arms, respectively) among all the types of non-strabismic anomalies of binocular vision. There was no gender predilection and no statistically significant differences were observed between the rural and urban arms in the prevalence of non-strabismic anomalies of binocular vision (Z-test, p > 0.05). The prevalence of non-strabismic anomalies of binocular vision was found to be higher in the 13 to 17 years age group (36.2 per cent) compared to seven to 12 years (25.1 per cent) (Z-test, p < 0.05). CONCLUSION: Non-strabismic binocular vision anomalies are highly prevalent among school children and the prevalence increases with age. With increasing near visual demands in the higher grades, these anomalies could significantly impact the reading efficiency of children. Thus, it is recommended that screening for anomalies of binocular vision should be integrated into the conventional vision screening protocol.

Binocular vision anomalies and normative data (BAND) in Tamil Nadu: report 1.

BACKGROUND: This population-based, cross-sectional study was designed to determine normative data for binocular vision and accommodative testing in rural and urban populations of Tamil Nadu. METHODS: A sample of 936 was determined, based on a previous pilot study. The epidemiological field work included a comprehensive eye examination and a binocular vision and accommodative assessment carried out in a total of four public schools, two each in the rural and urban arms of Chennai. An overall sample of 3,024 children between seven and 17 years of age was screened in the four schools and 920 children were included in the study. RESULTS: We found significant differences in expected values from the current clinical criteria for near point of convergence (NPC) with penlight, distance and near horizontal phorias, vergence facility, accommodation convergence/accommodation (AC/A) ratio, accommodative amplitudes, monocular and binocular accommodative facility (t-test: p < 0.001). The mean and standard deviation break/recovery values for NPC (in centimetres) with an accommodative target and penlight with red filter was 3 ± 3/4 ± 4 and 7 ± 5/10 ± 7, respectively. The mean accommodative amplitudes for the population could be estimated from the linear regression equation 16 - 0.3 × (age). The vergence facility was 12 ± 4 cycles/minute and 14 ± 4 cycles/minute in the seven to 10 and 11 to 17 age groups, respectively. Monocular accommodative facility was 11 ± 4 cycles/minute and 14 ± 5 cycles/minute and binocular accommodative facility was 10 ± 4 cycles/minute and 14 ± 5 cycles/minute in the seven to 12 and 13 to 17 age groups, respectively. The mean calculated AC/A ratio was 5.4 ± 0.6/1. CONCLUSION: The normative data for vergence and accommodative parameters for the Indian children between seven and 17 years of age are reported. The developmental trend of accommodation and vergence differences and significant differences in cut-off between the current data and available literature are reported. These differences have clinical implications for the interpretation, diagnosis and management of anomalies of binocular vision.

Natural history of idiopathic abducens nerve paresis in a young adult / Historia natural de paresia idiopática del nervio abducens en un adulto joven

The natural history of idiopathic abducens nerve paresis and the role of conservative management such as vision training during the recovery process is not well documented in the literature to the best of our knowledge. This case report presents the natural recovery process of idiopathic abducens nerve paresis in a young adult and the role of vision therapy in the recovery process (AU)

Hasta la fecha, la historia natural de la paresia idopática del nervio abducens y la función de un tratamiento conservador como la terapia visual durante el proceso de recuperación no se hallan bien documentadas en la literatura. Este informe de un caso presenta el proceso de recuperación natural de la paresia idiopática del nervio abducens en un adulto joven, así como la función de la terapia visual en el proceso de recuperación (AU)

Natural history of idiopathic abducens nerve paresis in a young adult.

The natural history of idiopathic abducens nerve paresis and the role of conservative management such as vision training during the recovery process is not well documented in the literature to the best of our knowledge. This case report presents the natural recovery process of idiopathic abducens nerve paresis in a young adult and the role of vision therapy in the recovery process.