Quality of life during occlusion therapy for amblyopia from the perspective of the children and from that of their parents, as proxy.

BACKGROUND: Parents pity their amblyopic child when they think that they suffer from occlusion therapy. We measured health-related quality of life during occlusion therapy. METHODS: We developed the Amblyopia Parents and Children Occlusion Questionnaire (APCOQ). It was designed by a focus group of patients, orthoptists and ophthalmologists and consisted of twelve items concerning skin contact of patch, activities, contact with other children, emotions and awareness of necessity to patch. Parents filled out the Proxy Version shortly before the Child Version was obtained from their child. Child Version item scores were compared with Proxy Version item scores and related to the child's age, visual acuity, refraction, angle of strabismus, and cause of amblyopia. RESULTS: 63 children were recruited by orthoptists, and their parents agreed to participate. Three children were excluded: one child with Down-syndrome, one child with cerebral palsy, and one child who had been treated by occlusion therapy. Included were 60 children (mean age 4.57 ± 1.34 SD) and 56 parents. Children had occluded 128 ± 45 SD days at interview. Prior to occlusion, 54 children had worn glasses. Cronbach's α was 0.74 for the Child Version and 0.76 for the Proxy Version. Children judged their quality of life better than their parents did, especially pertaining to skin contact and activities like games and watching TV. Notably, 13 children with initial visual acuity ≥ 0.6 logMAR in the amblyopic eye experienced little trouble with games during occlusion. Quality of life in eight children with strabismus of five years and older correlated negatively (Spearman rank mean rho = -0.43) with angle of strabismus. Children with amblyopia due to both refractive error and strabismus (n = 14) had, relatively, lowest quality of life, also according to their parents, as proxy. Several children did not know why they wore a patch, contrary to what their parents thought. CONCLUSIONS: Children's quality of life during occlusion therapy is affected less than their parents think, especially regarding skin contact, playing games and watching TV during occlusion. Quality of life correlates negatively with the angle of strabismus in children five years and older. Children do not know why they wear a patch, contrary to what their parents think. Notably, children with low visual acuity in the amblyopic eye, had little difficulty playing games.

Differences in quality-of-life dimensions of Adult Strabismus Quality of Life and Amblyopia & Strabismus Questionnaires.

PURPOSE: The Adult Strabismus Quality of Life Questionnaire (AS-20) and the Amblyopia & Strabismus Questionnaire (A&SQ) both measure health-related quality of life in strabismus patients. We evaluated to what extent these instruments cover similar domains by identifying the underlying quality-of-life factors of the combined questionnaires. METHODS: Participants were adults from a historic cohort with available orthoptic childhood data documenting strabismus and/or amblyopia. They had previously completed the A&SQ and were now asked to complete the AS-20. Factor analysis was performed on the correlation-matrix of the combined AS-20 and A&SQ data to identify common underlying factors. The identified factors were correlated with the clinical variables of angle of strabismus, degree of binocular vision, and visual acuity of the worse eye. RESULTS: One hundred ten patients completed both questionnaires (mean age, 44 years; range, 38-51 years). Six factors were found that together explained 78% of the total variance. The factor structure was dominated by the first four factors. One factor contained psychosocial and social-contact items, and another factor depth-perception items from both questionnaires. A third factor contained seven items-only from the AS-20-on eye strain, stress, and difficulties with reading and with concentrating. A fourth factor contained seven items-only from the A&SQ-on fear of losing the better eye and visual disorientation, specific for amblyopia. Current visual acuity of the worse eye correlated with depth-perception items and vision-related items, whereas current binocular vision correlated with psychosocial and social-contact items, in 93 patients. CONCLUSIONS: Factor analysis suggests that the AS-20 and A&SQ measure a similar psychosocial quality-of-life domain. However, functional problems like avoidance of reading, difficulty in concentrating, eye stress, reading problems, inability to enjoy hobbies, and need for frequent breaks when reading are represented only in the AS-20. During the development of the A&SQ, asthenopia items were considered insufficiently specific for strabismus and were excluded a priori. The patients who generated the items for the AS-20 had, in majority, adulthood-onset strabismus and diplopia and were, hence, more likely to develop such complaints than our adult patients with childhood-onset strabismus and/or amblyopia.

Patient-reported utilities in bilateral visual impairment from amblyopia and age-related macular degeneration.

BACKGROUND: Utility of visual impairment caused by amblyopia is important for the cost-effectiveness of screening for amblyopia (lazy eye, prevalence 3-3.5 %). We previously measured decrease of utility in 35-year-old persons with unilateral persistent amblyopia. The current observational case-control study aimed to measure loss of utility in patients with amblyopia with recent decrease of vision in their better eye. As these patients are rare, the sample was supplemented by patients with bilateral age-related macular degeneration with similar decrease of vision. METHODS: From our out-patient department, two groups of patients with recent deterioration to bilateral visual acuity less than Snellen 0.5 (bilateral visual impairment, BVI) were recruited, with either persistent amblyopia and age-related macular degeneration (AMB + AMD), or with bilateral age-related macular degeneration (BAMD). To measure utility, the time trade-off method and the standard gamble method were applied through interviews. Correlations were sought between utility values and visual acuity, age and Visual Function Questionnaire-25 scores. RESULTS: Seventeen AMB + AMD patients (mean age 72.9 years), and 63 BAMD patients (mean age 79.6 years) were included in the study. Among AMB + AMD, 80 % were willing to trade lifetime in exchange for cure. The overall mean time trade-off utility was 0.925. Among BAMD, 75 % were willing to trade, utility was 0.917. Among AMB + AMD, 38 % accepted risk of death in exchange for cure, overall mean standard gamble utility was 0.999. Among BAMD, 49 % accepted risk of death, utility was 0.998. Utility was not related to visual acuity but it was to age (p = 0.02). CONCLUSION: Elderly patients with BVI, caused by persistent amblyopia and age-related macular degeneration (AMD) or by bilateral AMD, had an approximately 8 % loss of TTO utility. Notably, the 8 % loss in elderly with BVI differs little from the 3.7 % loss we found previously in 35-year-old persons with unilateral amblyopia with good vision in the other eye. The moderate impact of BVI in senescence could be explained by adaptation, comorbidity, avoidance of risk and a changed percept of cure.

Utility analysis of disability caused by amblyopia and/or strabismus in a population-based, historic cohort.

BACKGROUND: Amblyopia (prevalence 3.4%) is in principle treatable, but approximately one quarter of children do not reach reading acuity in the amblyopic eye. Adults with persistent amblyopia and/or strabismus experience a decrease in quality of life. This was now quantified by patient-perceived utility values. METHODS: Subjects were born 1962-1972 and had been treated by occlusion therapy for amblyopia by one orthoptist 30-35 years ago. All children in Waterland with amblyopia and/or strabismus had been referred to this orthoptist. Utilities were derived by methods of time trade-off, TTO (lifetime traded against perfect vision) and standard gamble, SG (death risk accepted for perfect vision). Most troubling eye disorder (low acuity of the amblyopic eye, lacking stereopsis or strabismus) was chosen and ranked among nine chronic disorders according to the subject's perceived severity. RESULTS: From 201 patients that could be contacted 35 years after occlusion therapy--out of 471 who had been occluded--135 were included: 17 could not be reached, 34 refused, and 15 had other reasons to not participate. Mean age was 40.86 years; 53% were male. Seventy percent were willing to trade lifetime according to the TTO method; its mean (log) utility was 0.963, i.e., a decrease in quality of life of 3.7%. Thirty-seven percent accepted death risk according to the SG method; its mean utility was 0.9996. TTO outcomes correlated with current near and distance visual acuity. Low acuity of the amblyopic eye, chosen as most troubling eye disorder, ranked slightly less severe than tooth decay. CONCLUSION: Amblyopia and/or strabismus patients had a slightly decreased utility. The decrease is small but still important in the cost-effectiveness of vision screening because these conditions occur very frequently.

Construct validation of the Amblyopia and Strabismus Questionnaire (A&SQ) by factor analysis.

BACKGROUND: The Amblyopia and Strabismus Questionnaire (A&SQ) was previously developed to assess quality of life (QoL) in amblyopia and/or strabismus patients. Here, factor analysis with Varimax rotation was employed to confirm that the questions of the A&SQ correlated to dimensions of quality of life (QoL) in such patients. METHODS: Responses on the A&SQ from three groups were analyzed: healthy adults (controls) (n = 53), amblyopia and/or strabismus patients (n = 72), and a historic cohort of amblyopes born between 1962-1972 and occluded between 1968-1974 (n = 173). The correlations among the responses to the 26 A&SQ items were factor-analysed by Principal Component Analysis (PCA). As the development of the A&SQ was intuitive-deductive, it was expected that the pattern of correlation could be explained by the five a priori hypothesized dimensions: fear of losing the better eye, distance estimation, visual disorientation, diplopia, and social contact and cosmetic problems. Distribution of questions along the factors derived by PCA was examined by orthogonal Varimax rotation. RESULTS: Data from 296 respondents were analyzed. PCA provided that six factors (cutoff point eigenvalue >1.0) accumulatively explained 70.5% of the variance. All A&SQ dimensions but one matched with four factors found by Varimax rotation (factor loadings >0.50), while two factors pertained to the fifth dimension. The six factors explained 33.7% (social contact and cosmetic problems); 10.3% (near distance estimation); 8.7% (diplopia); 7.2% (visual disorientation); 6.3% (fear of losing the better eye); and 4.3% (far distance estimation), together 70.48% of the item variance. CONCLUSION: The highly explained variance in the A&SQ scores by the factors found by the PCA confirmed the a priori hypothesized dimensions of this QoL instrument.

Amblyopia and Strabismus Questionnaire (A&SQ): clinical validation in a historic cohort.

BACKGROUND: We recently developed the Amblyopia & Strabismus Questionnaire (A&SQ) to assess the quality of life in amblyopia and/or strabismus patients, and evaluated its content and criterion validity. The A&SQ was now validated clinically by correlating its outcome with past and current orthoptic parameters in a historic cohort of amblyopia and/or strabismus patients. METHODS: The cohort was derived from all 471 patients who were treated by occlusion therapy in the Waterland Hospital in Purmerend between 1968 and 1974 and born between 1962 and 1972. All children with insufficient visual acuity from the Waterland area had been referred to a single ophthalmologist and orthoptist. Of these, 203 were traced, and 174 filled out the A&SQ. In 137 of these, binocular vision, visual acuity, and angle of strabismus were reassessed 30-35 years after occlusion therapy. These clinical parameters were correlated with the five A&SQ domains: "distance estimation", "visual disorientation", "fear of losing the better eye", "diplopia", and "social contact and cosmetic problems". RESULTS: The current acuity at distance of the amblyopic eye and reading acuity of the amblyopic eye correlated significantly with all five A&SQ domains (significance level P = 0.01-P = 0.05). Weaker correlations were found for binocularity. In spite of the expectation that stereopsis should strongly correlate with the domain "distance estimation", and angle of strabismus with the domain "social contact and cosmetic problems", the acuity of the amblyopic eye was the overall dominant parameter. CONCLUSIONS: The adult acuity of the amblyopic eye seems the most important clinical determinant for quality of life in amblyopia and/or strabismus patients, even in domains of distance estimation, visual disorientation, and social contact and cosmetic problems, although intermediate determinants cannot be excluded.

The Amblyopia and Strabismus Questionnaire: English translation, validation, and subscales.

PURPOSE: To establish the English-language version of the Amblyopia and Strabismus Questionnaire (ASQE). DESIGN: Prospective cohort study. METHODS: A structured translation process was followed to generate the ASQE, a 26-item instrument (originally in Dutch) containing five subscales for fear of losing the better eye, distance estimation, visual disorientation, double vision, and social contact and appearance. The ASQE was administered to 150 adults in a private practice setting. All had strabismus with or without amblyopia and visual acuity of 20/50 or better in at least one eye. Subjects also completed a brief disability questionnaire, and they were further characterized by levels of unilateral vision loss, diplopia, and asthenopia. RESULTS: ASQE scores were highly correlated with the disability questionnaire outcomes (r = -.76, P < .0001). Internal consistency reliability (Cronbach alpha) of the subscales ranged from 0.80 to 0.92. Strong correlations were found between clinical characteristics and the ASQE (total score and subscale scores). CONCLUSIONS: The ASQE showed good psychometric properties that are in line with those of the original instrument. This, combined with strong correlations between ASQE scores and clinical characterization of the participants, establishes the ASQE as a useful tool for use in populations with strabismus and/or amblyopia.