What condition is characterized by a small optic disc often surrounded by a double ring?

The condition characterized by a small optic disc often surrounded by a double ring is optic nerve hypoplasia. This condition results from an underdevelopment of the optic nerve, leading to the optic disc appearing smaller than normal. The double-ring sign, which is a distinctive feature seen in imaging, occurs due to the presence of the myelinated nerve fibers that form a halo around the hypoplastic disc.

In optic nerve atrophy, the optic disc appears pale, reflecting damage or degeneration of the optic nerve, but it does not present with the double-ring appearance associated with optic nerve hypoplasia. Diabetic retinopathy involves changes to the retinal blood vessels and may lead to complications affecting the optic nerve but does not typically feature the specific anatomical characteristics associated with optic nerve hypoplasia. Glaucoma is primarily characterized by increased intraocular pressure and optic nerve damage, leading to a cupped appearance of the optic disc, not the small optic disc with a double ring.

Understanding these distinctions helps clarify why optic nerve hypoplasia is the condition described in the question.