| Palpebral fissure | |
|---|---|
| Front of left eye with eyelids separated to show medial canthus. (Palpebral fissure, visible but not labeled, is artificially widened.) | |
| Latin | rima palpebrarum |
| Gray's | subject #227 1025 |
Palpebral fissure is the anatomic name for the separation between the upper and lower eyelids. In adults, this measures about 10mm vertically and 30mm horizontally.
It can be reduced in horizontal size by fetal alcohol syndrome[1] and in Williams Syndrome. The chromosomal conditions Trisomy 9 and Trisomy 21 (Down Syndrome) can cause the palpebral fissures to be upslanted,[2] while Marfan Syndrome can cause a downslant.[3]
The fissure may be increased in vertical height in Graves' disease, which is manifested as Dalrymple's sign. This is one of the numerous symptoms of genetic disorders like Cri-du-chat.
In animal studies, using four times the therapeutic concentration of the ophthalmic solution Latanoprost (brand name Xalatan), the size of the palpebral fissure can be increased. The condition is reversible. Latanoprost is a prostaglandin F receptor agonist.[4]
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