Amblyopia and quality of life: a systematic review

Methodological quality of the review: Low confidence

Author: Carlton J, Kaltenhaler E.

Region: Details not provided

Sector: Amblyopia

Sub-sector: Quality of life

Equity focus: None specified

Review type: Effectiveness review

Quantitative synthesis method: Narrative analysis

Qualitative synthesis methods: Not applicable

Background

The impact of amblyopia on health-related quality of life (HRQoL) has not yet been adequately explored. Amblyopia is an important condition that can affect up to 5% of the general population. Despite an increasing body of evidence describing the effectiveness of amblyopia treatment, little robust evidence regarding HRQoL implications of the condition and/or its treatment is emerging. Within the allocation of health-care resources, there is increasing demand for evidence regarding not only treatment effectiveness but also the implication of the condition and/or the effect its treatment has on the patient in both the immediate and the long term. The use of patient-reported outcomes, such as HRQoL questionnaires, can be useful in determining the impact a condition has on an individual.

Research objectives

To undertake a systematic literature review to examine the HRQoL implications of amblyopia and/or its treatment, and to evaluate the measures identified in the reported studies.

Main findings

A total of 35 studies were included in the review. The majority of the studies (22) reported HRQoL from a parental perspective; nine studies reported results from adults who had amblyopia as a child; one study involved questioning both parents and children; and three studies reported results from the child’s perspective. In terms of the methodology used, five studies used an existing measure in their methodology to determine the impact of amblyopia on HRQoL; three studies used the Children’s Visual Function Questionnaire (CVFQ); one study used the Self-Perception Profile for Children (SPPC); and one used the Visual Function Index (VF-14). Five studies were identified that developed their own instruments, these include: Amblyopia Treatment Index (ATI), the Amblyopia and Strabismus Questionnaire (A&AQ), the Psychological Impact Questionnaire, the Patching Motivation Theory (PMT) Questionnaire, and the Patching Success Questionnaire (PSQ). Seven papers developed their own questionnaires, although the psychometric properties of these instruments were not disclosed. Six studies used qualitative methods to report the HRQoL implications of amblyopia and/or its treatment.

Studies reported mixed results in regards to the association between amblyopia and educational achievement. No statistically significant association between amblyopia and occupational classification was found. The risk of developing long-term vision loss in the better-seeing eye was reported to be greater for people with amblyopia. Amblyopia was not found to be associated with significant behavioural problems or bullying.

The HRQoL implications and/or its treatment were found to impact on family life (i.e. carer-child relationship), on social interactions (i.e. feelings of isolation), activities, feelings and behaviour (i.e. self-esteem).

Authors noted that it appears that the main HRQoL implications of amblyopia were related to treatment of the condition rather than to the condition itself. They also stated that the reported findings are of importance when considering the management of cases of amblyopia. Further research was required to assess the immediate and long-term utility effects of amblyopia and/or its treatment, using more robust methods of HRQoL assessment.

Methodology

Authors conducted a systematic search on 7 May 2010. The electronic databases searched included Scopus, NHS Economic Evaluation Database, Cochrane Methodology Register, Health Technology Assessment Database, Cochrane Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, CINAHL, and many others. Search strategies were performed to identify literature pertaining to amblyopia terms, amblyopia treatment terms, children terms, and QoL terms. No date or language restrictions were applied. Authors reported that 10 additional trials were identified via a HTA publication. However, it was not clear from the review if the authors conducted a reference search of included studies and experts were not contacted as part of the search strategy for additional trials. Although no language restriction was applied in the searches, at study selection stage, articles written in languages other than English were excluded. No inclusion criteria was reported for selection studies, although the authors excluded studies/letters/reviews/editorials if these were not related to the subject area or containing no data to inform the research question.

Study selection and data extraction of included studies were conducted by one reviewer; papers were assessed and data extracted using a data extraction form. Papers were examined in terms of the instruments used in the study. Newly developed HRQoL instruments identified were assessed in terms of reliability, validity, and responsiveness. Studies were also examined to determine whether respondents were children, parents, or adults who had undergone amblyopia treatment as child. HRQoL implications of amblyopia were extracted.

Authors conducted a narrative analysis of the instruments used in included studies.

Applicability/external validity

Authors did not discuss the applicability/external validity of findings.

Geographic focus

Authors did not provide the geographic focus of included studies in the review.

Quality assessment

The search for literature conducted by the authors was not sufficiently comprehensive to be confident that relevant studies were not omitted. Additionally, in terms of methods used to select studies and extract data of included studies risk of bias was not avoided as only one author conducted this process. These important limitations may affect the validity of the study. Authors recognized a number of limitations of the review, but these were not reported as limitations of the review. Therefore, a low confidence was attributed in the conclusions about the effects of this study.