Which of the following is NOT a condition of the retina?

Glaucoma is primarily an optic nerve condition rather than a direct disorder of the retina itself. It typically involves increased intraocular pressure that can damage the optic nerve and lead to vision loss. While glaucoma can have effects on vision related to retinal function, it does not originate in the retina like the other conditions listed.

Retinal detachment, macular degeneration, and diabetic retinopathy directly involve the retina. Retinal detachment refers to the separation of the retina from the underlying tissues, macular degeneration involves the deterioration of the macula affecting central vision, and diabetic retinopathy results from complications of diabetes that damage the blood vessels in the retina. Each of these conditions has a direct impact on the retinal structure and function, distinguishing them from glaucoma.