|LETTER TO THE EDITOR
|Year : 2017 | Volume
| Issue : 2 | Page : 171
Comment on: Comparison of serum sodium and potassium levels in patients with senile cataract and age-matched individuals without cataract
Eung Suk Kim1, Moosang Kim2, Seung-Jun Lee2, Sang Beom Han2
1 Department of Ophthalmology, Kyung Hee University Hospital, Kyung Hee University, Seoul, Korea
2 Department of Ophthalmology, Graduate School of Medicine, Kangwon National University Hospital, Kangwon National University, Chuncheon, Korea
|Date of Web Publication||24-Mar-2017|
Prof. Sang Beom Han
Department of Ophthalmology, Kangwon National University Hospital, 156 Baengnyeong-ro, Chuncheon, Kangwon 200-722
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Kim ES, Kim M, Lee SJ, Han SB. Comment on: Comparison of serum sodium and potassium levels in patients with senile cataract and age-matched individuals without cataract. Indian J Ophthalmol 2017;65:171
|How to cite this URL:|
Kim ES, Kim M, Lee SJ, Han SB. Comment on: Comparison of serum sodium and potassium levels in patients with senile cataract and age-matched individuals without cataract. Indian J Ophthalmol [serial online] 2017 [cited 2020 May 26];65:171. Available from: http://www.ijo.in/text.asp?2017/65/2/171/202862
We read with great interest the study by Mathur and Pai  entitled, “Comparison of serum sodium and potassium levels in patients with senile cataract and age-matched individuals without cataract,” in which the authors showed that higher serum sodium level is associated with increased risk of senile cataract. We believe that the authors should be congratulated for the great work as the results suggested that high sodium intake could be a risk factor of senile cataract, and underlined the importance of low salt diet, which is in accordance with a recent study on a large population in Korea.
Their study was undoubtfully well designed and conducted. However, we would like to point out that the study only evaluated serum sodium level. Although the serum sodium may have correlation with dietary sodium intake, it does not exactly reflect the amount of sodium intake. Total sodium intake can be estimated using urinary sodium to creatinine ratio (U[Na +]/Cr) of a spot urine sample. Bae et al. revealed the association between age-related cataract and dietary sodium intake by measuring U[Na +]/Cr. If the urine test could not be done, subjective dietary questionnaires could be helpful, as shown in a study which demonstrated the association between sodium intake and cataract.
They also assumed that alteration in serum sodium level might cause alteration in sodium concentration in aqueous humor, which might affect the development of cataract. To prove this postulate, it would be helpful to collect the aqueous humor sample from the cataract patients before surgery and evaluate the correlation between the sodium concentration in aqueous humor and the severity of cataract. Studies using animal models would also be interesting.
Although patients with systemic diseases affecting serum sodium level were excluded in their study, we are afraid that the possibility cannot be completely ruled out that patients who do not aware of their metabolic diseases or those with subclinical diseases were accidently included in the study. In these cases, detailed questionnaire and screening tests including blood chemistry panel could be valuable tools.
We believe that the authors can achieve even greater work in further studies with a larger population that include detailed patient questionnaire and laboratory tests including blood chemistry, urinalysis, and analysis of aqueous humor.
Financial support and sponsorship
This study was supported by the 2016 Kangwon National University Hospital Grant.
Conflicts of interest
There are no conflicts of interest.
| References|| |
Mathur G, Pai V. Comparison of serum sodium and potassium levels in patients with senile cataract and age-matched individuals without cataract. Indian J Ophthalmol 2016;64:446-7.
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Bae JH, Shin DS, Lee SC, Hwang IC. Sodium intake and socioeconomic status as risk factors for development of age-related cataracts: The Korea National Health and Nutrition Examination Survey. PLoS One 2015;10:e0136218.
Lee SG, Lee W, Kwon OH, Kim JH. Association of urinary sodium/creatinine ratio and urinary sodium/specific gravity unit ratio with blood pressure and hypertension: KNHANES 2009-2010. Clin Chim Acta 2013;424:168-73.
Cumming RG, Mitchell P, Smith W. Dietary sodium intake and cataract: The Blue Mountains Eye Study. Am J Epidemiol 2000;151:624-6.