Corneal refractive surgery and phakic intraocular lens for treatment of amblyopia caused by high myopia or anisometropia in children

Methodological quality of the review: Low confidence

Author: Tian Chunyu, Peng Xiujun, Fan Zhengjun and Yin Zhengqin

Region: Not reported

Sector: Amblyopia caused by high myopia

Subsector: High myopia treatment

Equity focus: No

Study population: Children

Type of programme: Hospital based

Review type: Other review

Quantitative synthesis method: Systematic review

Qualitative synthesis method: Not applicable

Background: Amblyopia therapy for refractive amblyopia consists of correcting significant refractive error with either spectacles or contact lenses and occlusion therapy or pharmacologic penalisation of the fellow eye. However, both methods have some drawbacks and are not suitable for all the cases, especially in monocular amblyopia secondary to anisometropia. Spectacle correction for extreme myopic or hyperopic refractive errors can lead to prismatically induced aniseikonia. Refractive surgery gave us new thoughts on treating these difficult cases. In 1995, Singh6 first reported the results of PRK in children with dense amblyopia caused by unilateral myopia and unequal hypermetropia. After surgery, best corrected vision acuity (BCVA) improved, with no inflammatory reactions, stable intraocular pressure, and good positioning in all eyes. So, they indicated that ICL implantation was a safe surgical procedure to correct amblyopia.

Objectives: To compare various visual function parameters, including the final visual acuity outcome and/or adverse events between corneal refractive surgery (CLRS) and phakic intraocular lens implantation (PIOLI) in the treatment of refractive amblyopic children.

Main findings: According to our search strategy, there were 25 articles, including 597 patients and 682 eyes, using refractive surgery for treating high myopic or anisometropic amblyopia. Among them, 21 articles reported the use of CLRS in the treatment of myopic anisometropia for 318 patients (13 PRK or LASEK and 8 LASIK). The mean age in CLRS group was (9.32±2.99) years (range from 1 to 17 years). The mean age in PIOLI was (8.08±2.99) years. The mean SE in CLRS group for the treatment of myopic anisometropia amblyopic patients was (-10.13±2.73) D and for the treatment of hyperopic anisometropia amblyopic patients was (5.58±1.28) D. When looking at the outcome between CLRS and p-IOLi, in both groups, the BCVA gain following intervention showed positive results. The gains in UCVA or BCVA range from mild to excellent, with no reported losses of acuity. In CLRS group, BCVA improved from 0.30±0.13 to 0.55±0.15 P<0.05, while in the p-IOLi group, BCVA improved from 0.09±0.05 to 0.42±0.14, P<0.05. Refractive errors were corrected in all the cases, although some patients suffered regression of more than 3D (20). There is no difference in postoperation SE between CLRS group (-0.33±-1.18) and PIOLI group (-0.42±-0.96, P>0.05. No severe complications were reported after pediatric refractive surgery in either group. The major complications in CLRS were myopic regression and haze.

Based on findings, authors conclude that both CLRS group and PIOLI group have advantages in treating refractive amblyopia in children. In comparing PIOLI with CLRS for treatment of refractive amblyopia, no statistically significant difference in final BCVA was observed.

Methodology:

All articles found were carefully reviewed to select those that reported original clinical data pre- and postoperatively. Articles were included if they reported data about refractive PIOLI with either CLRS or surgery in pediatric population with refractive error and/or amblyopia. Data from previously reported cases included in different articles were omitted, to avoid double calculation. Two reviewers separately evaluated the studies based on inclusion and exclusion criteria, and discrepancies were resolved by discussion. Age, surgical technique, and follow-up time were recorded.

Searches were conducted on PubMed, Embase and Controlled Trials Register databases for publications from 1991 to 2013. The following keywords were used: pediatric refractive errors and amblyopia, anisometropia, hyperopia, high myopia, LASIK, PRK, laser epithelial keratomileusis (LASEK), excimer laser, and phakic intraocular lens (PIOLI). There was no language restriction on the publications.

Applicability/external validity: Not discussed.

Geographic focus: Not discussed.

Summary of quality assessment:

Low confidence was attributed to the conclusions about the effects of this study, as important limitations were identified. Quality assessment of included studies were not reported, which may impact on the validity and reliability of findings. In addition, review authors did not contact authors/experts in the field as part of the search strategy.