Large optic nerve heads: megalopapilla or megalodiscs

Area of Science:

• Ophthalmology
• Optometry
• Medical Imaging

Background:

• Megalopapilla, a rare optic nerve head anomaly, is characterized by an enlarged optic disc.
• Its differentiation from glaucomatous optic neuropathy is clinically significant.
• Limited literature exists on megalopapilla, necessitating further investigation.

Purpose of the Study:

• To evaluate megalopapillas and determine if they represent a distinct population based on specific features.
• To compare megalopapillas with normal optic nerves and eyes with glaucoma.

Main Methods:

• Optic nerve head evaluation of 405 eyes using Heidelberg Retina Tomograph (HRT).
• Eyes included normal, pre-perimetric glaucoma, primary congenital glaucoma, and megalopapilla groups.
• Visual fields and intraocular pressure (IOP) were assessed; gonioscopy was performed.

Main Results:

• Megalopapilla group showed distinct stereometric parameters compared to normal and glaucoma groups.
• Congenital glaucoma and megalopapilla groups had similar disc areas.
• Megalopapillas differed from congenital glaucomas in rim volume and other parameters.

Conclusions:

• Megalopapilla is an entity with a large optic nerve head, potentially appearing abnormal with an increased cup.
• It is associated with normal rim volume, visual field, and intraocular pressure.
• Distinguishing megalopapilla from pseudoglaucomatous diseases requires special attention.