Refractive surgery for older children and adults with accommodative esotropia: a systematic review

Authors: Ferreira A, Marta A, Baptista PM, Caiado F, Abreu AC, Maia Set

Geographical coverage: Not reported

Sector: Biomedical

Sub-sector: Treatment

Equity focus: Children aged 8 years and above

Study population: Patients with a diagnosis of accommodative esotropia (AET).

Review type: Other review

Quantitative synthesis method: Systematic review

Qualitative synthesis method: Not applicable

Background: Accommodative esotropia (AET) is an eye condition caused by uncorrected hyperopia, deficient fusional divergence, or high accommodative convergence. Reducing hyperopia can alleviate this condition. LASIK and PRK are safe procedures for correcting hyperopia up to 4D, with LASIK being less painful and requiring less corneal regeneration. LASEK is another alternative with similar outcomes. For higher degrees of hyperopia, intraocular lenses (IOLs) implantation has been reported to yield satisfactory results. In theory, any method that reduces hyperopia should relax the ciliary muscle, thereby reducing accommodative convergence and strabismus.

Objectives: To assess whether laser refractive surgery is an acceptable alternative to glasses or contact lenses in adults and older children with and without binocular function.

Main findings:

Overall, evidence included in this review indicates that refractive surgery may be an alternative for spectacle correction for adults with AET ≤10PD. There is not enough evidence to recommend its use for patients under 18 years of age.

A total of 28 studies were selected for inclusion in this review. These comprised 22 case series with 378 patients and six case reports with eight patients. The case series involved 378 patients (726 eyes) aged between 8 and 52 years. All studies had a mean follow-up period of at least 12 months. Seven studies performed photorefractive keratectomy, nine conducted laser-assisted in-situ keratomileusis, one reported on laser-assisted sub-epithelial keratectomy, and three implanted intraocular lenses, including iris-fixated and collamer. Among the adult patients with a preoperative corrected esodeviation of ≤10 prism dioptres (PD) (n = 129), all but five (3.9%) exhibited orthophoria or ≤10PD post-refractive surgery. All but four children (4.5%) had an esodeviation of ≤10PD after surgery, with the exceptions ranging from 11-15PD. The review also included six case reports involving a total of eight patients (16 eyes) aged between 7 and 34 years, with a follow-up range of 4-48 months.

The findings of this review suggest that refractive surgery could be an alternative to glasses for adults with AET ≤10PD. However, there is insufficient evidence to endorse its use in patients under 18 years old. The safety and predictability of these procedures remain uncertain due to the distinct selection criteria used for these patients compared to standard indications, and the lack of long-term follow-up studies.

Methodology:

The review included observational and intervention studies that enrolled patients diagnosed with AET and reported outcomes of refractive surgery, written in English. There were no restrictions on patients’ age, type of refractive surgery, or previous strabismus procedures. Excluded were systematic reviews, guidelines, comments, editorials, studies not involving AET patients, studies reporting outcomes of non-refractive procedures, and non-English articles. There was no publication date restriction. A study including both AET and non-AET patients was included as it provided valuable surgical outcomes segregated by pathology.

A literature search was coducted from inception to 24 March 2021 in the following four databases: PubMed, ISI Web of Science, Cochrane Central Register of Controlled Trials, and Scopus. In addition, the reference lists of the selected studies and previously published literature reviews were manually reviewed.

The two authors independently assessed the full-text for inclusion status, and discrepancies were solved by consensus after an additional review of the studies. The Meta-analysis Of Observational Studies in Epidemiology guidelines was used to select the information to be extracted. No meta-analysis was performed due to heterogeneity of studies.

Two reviewers independently evaluated the risk of bias for each eligible study using the using the Joanna Briggs Institute Critical Appraisal tool. For the case series, the item “Was there clear reporting of the presenting site(s)/clinic(s) demographic information?” was not assessed as it was deemed irrelevant to this topic by the authors.

Applicability/external validity: The authors highlighted several limitations of their work. They did not perform a meta-analysis due to the heterogeneity of the studies. The studies were of low evidence and non-comparative, limiting the generalizability of the conclusions. Most studies did not discriminate outcomes based on binocular function, and the lack of binocular function assessment and differentiation between patients with FAET and PAET was a significant limitation. Despite comprehensive reference cross-checking and searching four databases, the possibility of missing relevant studies was acknowledged.

Geographic focus: Not reported

Summary of quality assessment:

The approaches used to identify, include and critically appraise studies were generally robust, with at least two authors undertaking all key tasks. However, the search was somewhat limited in that it did not seek to incorporate unpublished material and no relevant experts were contacted. While the approaches to the analysis of the data were also generally rigorous, no attempt was made to consider separately the results for studies involving different levels of risk of bias. Coupled with the fact that the authors regard the evidence utilised overall as being ‘low level’, this would lead us to have low confidence in the findings of this review.