International Journal of Medical Sciences · 3 authors, 2 centres
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This study found that serum sodium levels were significantly higher in senile cataract patients (mean 144.96 mEq/L) compared to healthy controls (mean 140.88 mEq/L), while potassium levels did not differ. The elevated sodium levels suggest that high dietary sodium intake may be a risk factor for age-related cataract formation. These findings could inform dietary recommendations to reduce cataract risk, as sodium intake is modifiable.
**Background**: Senile cataract is a common age-related lens opacity affecting over 75% of people over 75 years and is a major cause of blindness worldwide. Its pathogenesis involves multiple factors including aging, genetics, ultraviolet light exposure, diet, and metabolic disorders. The lens receives nutrients from the aqueous humor, which is derived from blood, so changes in serum electrolytes could influence lens metabolism and cataract formation. This study aimed to compare serum sodium (Na+) and potassium (K+) levels in patients with senile cataract versus healthy controls.
**Methods**: The study included 155 senile cataract patients (79 females, 76 males; mean age 61.96 ± 14.5 years, range 44–85) scheduled for cataract surgery at the eye clinic of Rasoul Hospital, Tehran, Iran, and 155 normal individuals (79 females, 76 males; mean age 59.63 ± 13.8 years, range 43–86) who were close relatives of the patients. Both groups underwent thorough ophthalmic examination (visual acuity, slit lamp, ophthalmoscopy, intraocular pressure) and were excluded if they had any systemic disease, hypertension, drug intake, or other ophthalmic conditions or surgery history. Fasting blood samples were collected, and serum Na+ and K+ levels were measured using flame photometry (SEAC model FLP20, Italy). Means were compared using the t-test with SPSS 11 software.
**Key Results**: Mean serum Na+ level was significantly higher in cataract patients (144.96 ± 6.04 mEq/L) compared to controls (140.88 ± 2.27 mEq/L), with a p-value < 0.0001. Mean serum K+ level was not significantly different between groups: 4.20 ± 0.34 mEq/L in cases vs. 4.15 ± 0.32 mEq/L in controls. Although the Na+ levels in patients were within the normal range (135–150 mEq/L), the difference was statistically and clinically meaningful.
**Clinical Implications**: The elevated serum Na+ in senile cataract patients suggests that high dietary sodium intake may be a risk factor for age-related cataract. The lens maintains a low Na+ and high K+ concentration via Na+/K+ ATPase pump activity, which is sensitive to extracellular cation concentrations. High serum Na+ could alter aqueous humor composition, disrupt lens cation balance, and promote cataractogenesis. This finding aligns with previous studies (e.g., Clayton et al., Philips et al.) and highlights the potential for dietary modification to reduce cataract risk. However, the Italian-American Cataract Study found no such association, possibly due to differences in diet and nutrition across populations. Further research in diverse populations with controlled diets is needed to confirm these results and inform public health strategies.