Spectacle non-tolerance in clinical practice – a systematic review with meta-analysis

Authors: Bist J, Kaphle D, Marasini S, Kandel H.

Geographical coverage: England, Australia, India, Canada and the United States

Sector: Risk and burden of disease

Sub-sector: Prevalence and causes of spectacle non-tolerance

Equity focus: None specified

Study population: General population

Review type: Other review

Quantitative synthesis method: Narrative synthesis and meta-analysis

Qualitative synthesis method: Not applicable

Background:

The use of spectacles for the correction of refractive errors dates back to the thirteenth century. Advances in spectacle designs allow choices based on shape, size and the magnitude of the prescription to correct refractive errors (namely, myopia, hypermetropia, astigmatism and presbyopia). Spectacle non-tolerance or adverse events to spectacle wear are serious concerns for both patients and practitioners. Non-tolerance may contribute to a negative impact on the practitioner’s ability and practice. Therefore, a detailed understanding of frequency and causes of spectacle non-tolerance in clinical ophthalmic practice is essential.

Objectives:

This review aimed to determine the prevalence and causes of non-tolerance to spectacles prescribed and dispensed in clinical practice.

Main findings:

Authors included five studies in the meta-analysis. The age of the participants ranged between 3 and 97 years with a total sample size of 205,478 participants. Studies were conducted in England, Canada, India, Australia and the United States. All studies were cross-sectional and two were retrospective in design.

The prevalence of spectacle non-tolerance was based on four studies. Authors report the pooled prevalence of spectacle non-tolerance of 2.1% (95% CI: 1.6-2.7) although a substantial heterogeneity between studies was noted at I² = 89%. Subgroup analysis and meta-regression were not performed because of the small number of studies.

Authors used studies from the five included studies to analyse causes of non-tolerance to spectacles and found errors in refraction as the most common cause with a pooled estimate of 47.4% (95% CI: 41.6-53.3) of all non-tolerance reported.

The pooled estimate of non-tolerance due to communication reported by the authors was 16.3% (95% CI:0.0-45.3). Common communication issues identified were unsatisfactory communication with the patient, no common language between the patient and the clinician, unreasonable expectation in improvement of vision and patient’s expectation to see in the distance with the near correction.

The researchers discovered that the occurrence of dispensing errors in non-tolerance cases varied between 5.8% and 22%, with an overall estimate of 13.5% (95% CI: 6.1-23.0). They also found that non-adaptation was observed in 9.7% (95% CI: 7.5-12.1) of non-tolerant cases across four studies. Data entry mistakes were responsible for 8.7% (95% CI: 0.0-28.5) of non-tolerances in three evaluated studies. In three studies, non-tolerance due to binocular vision issues was found in 7.4% (95% CI: 0.7-18.8) of all non-tolerant cases. The common binocular vision problems leading to non-tolerance included anisometropia, vertical and lateral deviations, and convergence insufficiency. Non-tolerance due to ocular pathology was estimated to be present in 6.4% (95% CI: 0.0-17.1) of all non-tolerance cases, ranging from 0.75% to 16.8%. Although five studies identified pathology as a cause of non-tolerance, one study did not specify the particular pathology causing non-tolerance.

Methodology:

The authors reviewed quantitative studies in English that discussed spectacle non-tolerance, defined as patients returning to the eye clinic due to difficulties adapting to new prescriptions. The review included studies regardless of patient age, gender, or location, but excluded community-level studies, studies on spectacle use compliance related to issues like breakage or peer pressure, and studies on non-tolerance to other refractive corrections. Qualitative studies, case reports, case series, and review articles were also excluded.

Authors conducted a search in PubMed, Scopus and the Web of Science for articles published up to July 2020.

Authors extracted data of studies, including reference details (author’s name, year, etc.) sample size, spectacle prescriptions, number of non-tolerance incidents and the causes of non-tolerance. To assess the quality of included studies, authors used the Newcastle-Ottawa Scale (NOS), modified for cross-sectional studies.

Study selection, data extraction and quality assessment were conducted by two reviewers independently. Authors conducted a meta-analysis by pooling data on the prevalence of spectacle non-tolerance. The non-tolerance prevalence from individual studies was pooled using a random-effects model, and the pooled estimates along with the 95% confidence interval (CI) were calculated. Heterogeneity was evaluated using the I² statistic and categorised as low, moderate and high for I² values of 25%, 50% and 75%, respectively.

Applicability/external validity:

Authors did not discuss the generalisability of findings. However, it should be noted that studies in this review are highly heterogenous with small sample sizes which impacts on the generalisability of findings of this review.

Geographic focus:

Authors note that studies in the review were from high income countries and tertiary super-specialty clinics, as no studies from low resources were identified. Authors further note that spectacle non-tolerance could be a bigger issue in limited-resource settings where there may be appropriately trained refraction professionals and licensed or regulated optical dispensers.

Summary of quality assessment:

Authors clearly defined inclusion criteria and used systematic methods to search, screen and extract data, and appraise studies to be included in the review. In addition, authors used appropriate methods to pool data for the statistical analyses and clearly report the limitations of included studies in the review. However, important limitations were identified: they limited the review to peer-reviewed articles written in the English language, which may have introduced publication and language bias. Given review conclusions are not representative of the available literature, we have low confidence in the conclusions about the effects of this study.