The Relationships between Anterior Chamber Parameters and Obesity

Dear Editor,

We read with interest the article titled "Evaluation of anterior segment parameters in obesity" [1], in which the authors showed that obesity was associated with higher intraocular pressure (IOP) and lower anterior chamber depth (ACD). The study was undoubtfully well designed and conducted, and the results were clear.

However, in the Materials and Methods section, the manner in which "age- and sex-matched healthy subjects" were randomly selected from a general population to prevent bias should be described more specifically, because there might be a concern about selection bias. Comparison of the ages between the two groups should also be performed to show the similarity in age distribution between the two groups.

In the Discussion section, the authors postulated that increase in retrobulbar fat associated with obesity might cause a decrease in ACD and an increase in IOP. In addition, there should be explanation for the lack of difference in axial length between the two groups. Evaluation of the grade of cataract could also be helpful as cataract might have influenced the decrease in ACD. Investigation and comparison of exophthalmometric values could also be useful to determine the presence of eyeball protrusion caused by the pressure from increased retrobulbar fat. In addition, because body height might be positively correlated with both ACD and axial length [2], inclusion of the height in the analyses would produce more meaningful results. Although the authors showed that anterior chamber angle had significant correlation with body mass index (BMI), there was no significant difference in anterior chamber angle in a comparison between the two groups. Multivariate analysis would be necessary to address the controversy, as well as to exclude the effects of confounding factors.

Finally, we would like to point out that the mean BMI in the obese group was 39.8, which suggests that most of the patients were not simply obese, but severely obese with class II (BMI between 35.0 and 39.9) or III obesity (BMI ≥40.0) [3]. Therefore, although the results did show that patients with severe obesity might have increased IOP and decreased ACD, it appears that addition studies should be performed to evaluate the changes in anterior segment parameters in patients with class I obesity (BMI between 30.0 and 34.9) and overweight patients (BMI between 25.0 and 29.9).