102 e-Letters

published between 2019 and 2022

  • Comments on: Association of low birth weight with myopic refractive error and lower visual acuity in adulthood: results from the population-based Gutenberg Health Study (GHS)

    Dear Editor,

    We read the article published by Fieß, et al (1) with considerable interest and laud them on their study and the large cohort. Considerable work has been done earlier, which looks at factors associated with refractive errors, however few studies document association with birth weight. Keeping this in mind, we feel that there are a few points requiring further clarity in this article.

    The authors mention their inability to control for factors such as paternal refractive error and family history. However, previous studies not only discuss the paternal refractive error and family history, but also expand the affecting factors to include the number of myopic parents. (2) In the study design described by Höhn et al. where comprehensive information on living conditions and birth weight was collected via computer-assisted telephone interviews, (3) information on number of myopic parents could also have been collected, and would have proven to be an important covariate in the analysis.

    The authors also report that 8369 participants provided birth weight data, of which 45 were excluded due to unreliable self-reported data [<1000g (n=7) or >6000g (n=38)]. However, tables 2 and 3 report analysed results based on 8369 participants not 8324 (after exclusion of the 45). Even though 45 is an insignificant number, and does not affect the results as such, this aspect of the results needs further clarity.

    Lastly, while the authors mention, furt...

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  • Inclusion criteria and non-cycloplegyc examinations in study of refractive errors in Colombia

    We thank Dr. Tobon for his comments regarding our recently published article on refractive errors frequency in Colombia.1
    Initially he referred to the exclusion of the participants with less than 20/40 of distance corrected vision. The explanation of the application of this criterium was that, since as it has been shown, reproducibility of manifest refraction is less in patients with bad distance corrected visual acuity, and in this study we needed to have a very reliable manifest refraction examination.2
    However, we believe that Dr. Tobon highlights a very interesting point, which is worth analyzing in more detail. Ours and other studies that have analyzed the prevalence of refractive errors in a population have excluded eyes with other ocular conditions, including amblyopia. For example, in the study conducted in Mexico by Gomez-Salazar et al, which included a very large sample (more than 670,000 patients), they excluded patients with amblyopia.3 This made it impossible to analyze the frequency of amblyopia or anisometropia.
    In our study we excluded those patients with less than 20/40 of distance corrected visual acuity in any eye. Unfortunately, we did not keep the information on those patients excluded, and therefore we cannot determine the exact number or diagnosis of those cases. For future studies we will record such information.
    With regard to the second query of Dr. Tobon, we decided not to use cyclopegic refraction in this study, performed...

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