Probing of the tear duct may be useful treatment for patients with:

Probing of the tear duct is a procedure often performed to address issues related to tear drainage, specifically in cases of blocked or narrowed tear ducts, leading to excessive tearing, known as epiphora. When there is a blockage in the nasolacrimal duct, tears accumulate and overflow onto the face, causing discomfort and cosmetic concerns. Probing helps to clear the obstruction, allowing tears to drain properly and alleviating the symptoms associated with excessive tearing.

In contrast, the other conditions listed do not primarily involve the tear drainage system. Epicanthus refers to a fold of skin at the inner corner of the eye, esophoria is a type of eye misalignment or strabismus where one eye tends to turn inward, and episcleritis is an inflammatory condition affecting the outermost layers of the eye. None of these conditions would benefit from probing of the tear duct, as they are related to different anatomical or physiological issues. Therefore, probing is specifically beneficial for patients with epiphora, making it the correct answer.