Veterinary Ophthalmology Practice Test 2025 - Free Veterinary Eye Specialist Practice Questions and Study Guide

The enzyme responsible for converting glucose to sorbitol in the lens is aldose reductase. This enzyme plays a crucial role in the polyol pathway, where it catalyzes the reduction of glucose into sorbitol using NADPH as a cofactor. Sorbitol is a sugar alcohol that can accumulate in the lens of the eye, particularly in conditions such as diabetes mellitus, leading to osmotic and oxidative stress that contributes to cataract formation.

Hexokinase is primarily involved in the phosphorylation of glucose to glucose-6-phosphate and does not participate in the conversion to sorbitol. Glucosidase is related to the hydrolysis of glycosidic bonds in carbohydrates, while lactate dehydrogenase is involved in the conversion of pyruvate to lactate in anaerobic glycolysis. None of these enzymes are directly involved in the specific reaction of converting glucose to sorbitol, which is why aldose reductase is the correct choice for this question.