Megalopapilla is a non-progressive
human eye
The human eye is a sensory organ, part of the sensory nervous system, that reacts to visible light and allows humans to use visual information for various purposes including seeing things, keeping balance, and maintaining circadian rhythm.
...
condition in which the
optic nerve head
The optic disc or optic nerve head is the point of exit for ganglion cell axons leaving the eye. Because there are no rods or cones overlying the optic disc, it corresponds to a small blind spot in each eye.
The ganglion cell axons form the ...
(optic disc) has an enlarged
diameter, exceeding 2.1 mm with no other morphological abnormalities.
Clinical features
In megalopapilla the
optic disc
The optic disc or optic nerve head is the point of exit for ganglion cell axons leaving the eye. Because there are no rods or cones overlying the optic disc, it corresponds to a small blind spot in each eye.
The ganglion cell axons form the ...
diameter exceeds 2.1 mm (or surface area more than 2.5 mm
2) with an increased
cup-to-disc ratio.
Although the optic disc is looks abnormal, the disc colour, sharpness of disc margin, rim volume, configuration of blood vessels and
intraocular pressure will be normal.
is normal except for an enlarged
blind spot.
may be normal,
or occasionally reduced.
Types
There are two types of megalopapilla. Type 1, which is the most common, is bilateral with a normal configuration of the
optic cup.
Type 2 is unilateral with a superiorly displaced cup that eliminates the adjacent neuro-retinal rim.
Diagnosis and differential diagnosis
Large disc size can be seen in
fundus
''Fundus'' (Latin for "bottom") is an anatomical term referring to that part of a concavity in any organ, which is at the far end from its opening. It may refer to: Anatomy
* Fundus (brain), the deepest part of any sulcus of the cerebral cortex
* ...
examination by
ophthalmoscopy. Since
OCT is not influenced by disc size, it can be used in differentiating normal and glaucomatous eyes with large discs.
Since the clinical appearance of megalopapilla resembles that of glaucomatous optic disc, it should be differentiated from
Normal tension glaucoma Normal tension glaucoma (NTG) is an eye disease, a neuropathy of the optic nerve, that shows all the characteristics of primary open angle glaucoma except one: the elevated intraocular pressure (IOP) - the classic hallmark of glaucoma - is missing. ...
and other pseudo-glaucomatous diseases.
Other conditions that resembles megalopapilla includes
coloboma of optic disc and orbital optic disc
glioma.
History
Bock and Franceschetti were the first to use the term megalopapilla to describe larger-than-normal optic disks.
References
{{Congenital malformations and deformations of eye
Congenital disorders of eyes