Optometrists prescribe and fit eyeglasses and contact lenses and counsel patients on contact lens use and care, visual hygiene, lighting arrangements, working distances and safety factors. If lenses are prescribed, the optometrist usually has an assistant select and adjust frames that suit the patient. Few practitioners carry out interpretation of visual examinations only. Most prefer to supply the materials used in their own prescription in order to give a complete visual service and ensure satisfactory results. The ophthalmic materials themselves, that is, glasses or contact lenses, are generally produced by optical laboratories.
Some patients require vision training or eye exercises rather than lenses.
This branch of vision care is called orthoptics. This is particularly useful for children with binocular problems. Some optometrists specialize in this field. Fitting contact lenses is an important aspect of optometrists' work, and some may specialize in this. Still another specialization concerns the fitting of special lenses for patients whose vision cannot be corrected by ordinary spectacle lenses.