What is the primary use of methylcellulose (Isopto Tears)?

Methylcellulose, commonly referred to as Isopto Tears when used in ophthalmic preparations, serves primarily to provide tear-like lubrication for individuals experiencing dry eyes. It mimics the natural tears, helping to alleviate discomfort and protect the eye surface by maintaining moisture. This lubricating action is essential for comfort in those with reduced tear production or environmental factors causing dryness.

The other options pertain to different uses. While eye medications can include lubricants, the direct intent of methylcellulose is not to aid in delivering other medications (as indicated in the first option). The treatment of eye infections requires antimicrobial agents, which methylcellulose does not provide. Pupil dilation is typically achieved through mydriatic agents, not through lubricating solutions like methylcellulose. Thus, the primary function of methylcellulose is accurately reflected as providing tear-like lubrication for the eyes.