Tracking changes in cone function is useful in managing the progression of the disease as well as efficacy of treatment.
Cone function, unlike visual acuity, is affected early in disease, often before the patient is aware of any vision loss. Even in the moderate stages of AMD and Glaucoma, patients frequently test at or near normal visual acuity.
Identifying cone function degradation may identify disease earlier, allowing treatment in the earliest stages of disease. Cone function continues to diminish as the disease progresses and in some cases, may recover upon treatment.