Inappropriate prescription of prism glasses for obligate fixation disparity measured with the Pola test

In the subjective measurement of fixation disparity (FD), the subject sees and fuses contours presented in the peripheral macular areas of both eyes ('fusion loek', a square for instanee). The pointing direction of the foveolae of both eyes relative to each other is determined by means of two haploscopically seen objects presented in the central visual field (Fig. la). ..

Long-term follow-up of an amblyopia treatment study: change in visual acuity 15 years after occlusion therapy

Purpose: To determine change in visual acuity (VA) in the population of a previous amblyopia treatment study (Loudon 2006) and assess risk factors for VA decrease. Methods: Subjects treated between 2001 and 2003 were contacted between December 2015 and July 2017. Orthoptic examination was conducted under controlled circumstances and included subjective refraction, best corrected VA, reading acuity, binocular vision, retinal fixation, cover-uncover and alternating cover test. As a measure for degree of amblyopia, InterOcular VA Difference (IOD) at the end of occlusion therapy was compared with IOD at the follow-up examination using Wilcoxon’s signed-rank test. Regression analysis was conducted to determine the influence of clinical and socio-economic factors on changes in IOD. Results: Out of 303 subjects from the original study, 208 were contacted successfully, 59 refused and 15 were excluded because of non-amblyopic cause of visual impairment. Mean IOD at end of therapy (mean age 6.4 years) was 0.11 ± 0.16 logMAR, and IOD at follow-up examination (mean age 18.3 years) was 0.09 ± 0.21 logMAR; this difference was not significant (p = 0.054). Degree of anisometropia (p = 0.008; univariable analysis), increasing anisometropia (p = 0.009; multivariable), eccentric fixation (p < 0.001; univariable and multivariable); large IOD (p < 0.001; univariable and multivariable) and non-compliance during therapy (p = 0.028; univariable) were associated with IOD increase. Conclusion: Long-term results of occlusion therapy were good. High or increasing anisometropia, eccentric fixation and non-compliance during occlusion therapy were associated with long-term VA decrease. Subjects with poor initial VA had a larger increase despite little patching, but often showed long-term VA decrease

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

Predictors and a remedy for noncompliance with amblyopia therapy in children measured with the occlusion dose monitor

PURPOSE. Noncompliance is one of the limiting factors in the success of occlusion therapy for amblyopia. Electronic monitoring was used to investigate predictors of noncompliance, and, in a prospective randomized clinical trial, determined the effectiveness of an educational program. METHODS. Compliance was measured electronically during 1 week every 3 months in 310 newly diagnosed amblyopic children. The family's demographic parameters and the child's clinical parameters were assessed for their influence on the level of compliance. In addition to standard orthoptic care, children were randomized to receive an educational cartoon story, reward stickers, and an information sheet for the parents (intervention group), or a picture to color (reference group). These and the electronic device were distributed during home visits by researchers. The primary outcome measure was the percentage of compliance (actual/prescribed occlusion time) in the two groups. The secondary outcome measure was the influence of demographic and clinical factors on compliance. RESULTS. Compliance was associated with parental fluency in the national language, country of origin, level of education, and initial visual acuity of the child. During the first 1-week measurement period children in the intervention group had better compliance than the reference group had (78% ± 32% vs. 57% ± 40%; P < 0.0001), and fewer children were not occluded at all (3 vs. 23 in the reference group; P < 0.0001). This difference remained throughout the study period. CONCLUSIONS. Poor parental fluency in the national language, a low level of education, and poor acuity at the start of treatment were predictors of low compliance. An educational program primarily aimed at the child improved compliance and reduced the number of children who did not comply with occlusion at all. Copyrigh