Early development of selenium-induced cataract: slit lamp evaluation

Area of Science:

• Ophthalmology
• Toxicology
• Lens Biology

Background:

• Cataracts are a leading cause of blindness worldwide.
• Selenium is an essential trace element, but elevated levels can be toxic.
• Understanding the mechanism of toxic cataractogenesis is crucial for prevention and treatment.

Purpose of the Study:

• To document the sequence of early lenticular changes preceding cataract formation induced by elevated selenium levels in a rat model.
• To investigate the initial site of selenium's action in the development of nuclear cataracts.

Main Methods:

• Rats were administered an elevated dose of selenium.
• Ocular examinations were performed at various time points post-injection (13 hours to 10 days).
• Morphological changes in the lens, including cataract development and fiber alterations, were documented.

Main Results:

• Posterior equatorial subcapsular cataract (PESC) formed within 13-24 hours.
• Cortical changes and perinuclear fiber swelling appeared between 24-72 hours.
• Dense central nuclear cataracts developed by three to five days, with progression observed up to 10 days.

Conclusions:

• Selenium-induced cataract formation in rats progresses through distinct stages, initiating with changes outside the lens nucleus.
• The findings support the hypothesis that selenium's primary action is extranuclear, preceding nuclear cataract development.
• This research provides insights into the toxicological mechanisms of selenium on ocular tissues.