The effect of verapamil in the prevention of radiation-induced cataract.

PURPOSE

Cataract is an unavoidable complication when radiation therapy includes the lens, even in small doses. Alterations in the ion content of the lens were considered to play an essential role in cataract formation. In this experimental study, the effect of verapamil on ion concentrations within the irradiated lenses was investigated in rats.

METHODS AND MATERIALS

Forty female Wistar albino rats, each weighing 180-250 g, were divided into three groups: (a) radiation treated (n = 10); (b) no treatment (n = 10); (c) or a combination of radiation and verapamil (n = 20). Both the radiation group and verapamil-treated group received 5 Gy radiation to the cranium in a single fraction, including the eyes, within the irradiation volume. All animals were sacrificed by bleeding, 7.5 weeks posttreatment. Calcium, sodium, and potassium levels were measured in blood and in lens homogenates. However, for technical reasons, magnesium levels could only be studied in lens homogenates.

RESULTS

Potassium and sodium concentrations in lens homogenates did not differ in the control and radiation groups, but both were significantly lower in the verapamil-treated group (p = 0.001, p = 0.009, respectively). Calcium levels were higher in the radiation group and lower in the verapamil-treated group compared to the controls (p < 0.0001); magnesium levels did not differ (p = 0.37).

CONCLUSION

Verapamil effectively decreased the lens calcium concentration, which is accepted as the key element in radiation cataractogenesis. It is therefore concluded that verapamil may reduce the risk of radiation-induced cataract formation.