January 3, 2023
By Geetha Sravani, PhD Candidate, Brien Holden Vision Institute
Due to the rise in the global prevalence of myopia and the associated burden, there is a need to understand the impact of widely used strategies to manage myopia and their impact on the progression of myopia. Multiple surveys conducted over the years have indicated that a common strategy used to manage myopia is to simply correct the refractive error. Furthermore, many practitioners continue to undercorrect myopia. The premise is that undercorrection of myopia results in myopic defocus, which in animal models has been shown to slow the progression of myopia. Similar questions have been raised around uncorrection or no correction of myopia. However, there has been no evidence that indicates that these measures help slow myopia progression.
Logan and Wolffsohn conducted a systematic review and meta-analysis of the evidence to better understand the relationship between under and overcorrection of myopic refractive error and myopia progression in children and adolescents aged up to 18. Eight prospective cohort studies and one retrospective analysis were included in the review.
Their analysis indicated conflicting results with undercorrection of myopia; while few studies showed no difference in myopia progression, most indicate an acceleration or increase in myopia progression compared to those fully corrected. There were few studies exploring no correction (only two). The results were equivocal, with one study reporting faster progression and the other reporting less progression. Similarly, a single study systematically studying monovision found slower progression, whereas another reported faster progression. In summary, the authors concluded that given the lack of support for any of the above strategies to slow myopia, uncorrected, monovision, and overcorrection are not beneficial and advise for full correction of myopia.
Role of Un‐Correction, Under-Correction, and Over-Correction of Myopia as a Strategy for Slowing Myopic Progression
Nicola S Logan & James S Wolffsohn
This systematic review investigates the association between un-, under- and over-correction of myopic refractive error and myopia progression in children and adolescents (up to 18 years of age). The literature search included three databases (PubMed, Web of Science, and Cochrane Central Register of Controlled Trials [CENTRAL]) and reference lists of retrieved studies in any language. Eight prospective cohort studies and one retrospective analysis of clinical data provided comparison data on un- and under-correction of myopia versus full correction of myopia; however, the quality of studies and length of follow-up times varied. A forest plot showed no beneficial effect of under-correction, with some studies finding an increase in myopia progression. While one study suggested that myopia progression is slower in an un-corrected cohort compared to those who are fully corrected, another study suggests the opposite. One study utilised anisomyopes to allow comparison of under-correction of one eye with full correction of the fellow eye indicating that under-correction in one eye appears to slow the rate of myopia progression in that eye. Another study on full correction only in one eye found that progression was faster in the un-corrected eye. No benefits of over-correction of myopia were found. The overall findings are equivocal with under-correction causing a faster rate of myopia progression. There is no strong evidence of benefits from un-correction, monovision, or over-correction. Hence, current clinical advice advocates for the full correction of myopia. Further studies are warranted to determine the level of myopia that can be left uncorrected without impacting myopia progression and how this changes with time.
Logan, N. S., & Wolffsohn, J. S. (2020). Role of un‐correction, under‐correction, and over‐correction of myopia as a strategy for slowing myopic progression. Clinical and Experimental Optometry, 103(2), 133-137.
|Geetha Sravani is a PhD candidate at the Brien Holden Vision Institute, supervised by Prof. Padmaja Sankaridurg and Arthur Back. Her research focuses on the role of pupillary responses in myopia.|