Methods of diagnosing meibomian gland dysfunction are disclosed. The methods may be standardized and provide an accurate diagnosis of whether meibomian gland dysfunction exists. In one embodiment, a method is provided that utilizes an evaluation tool to apply a force for a preselected period of time to at least one of a plurality of meibomian glands in two or more regions of a plurality of regions of an eyelid. A grade is assigned to the at least one meibomian gland of the plurality of meibomian glands in each of the two or more regions based on any secretion that is expressed from each meibomian gland. In this manner, a plurality of meibomian gland secretion grades is obtained. The plurality of meibomian gland secretion grades is indicative of the presence of meibomian gland dysfunction.