Plica semilunaris temporal ectopia: evidence of primary nasal pterygia traction.
OBJECTIVE
To study whether plica semilunaris (PS) temporal ectopia is associated with primary nasal pterygia and whether such hypothetical ectopia is linked to with-the-rule astigmatism so that a discussion of the clinical and surgical implications of such possible findings might take place.


METHODS
Cross-section observational study of 208 consecutive eyes of 152 cases and 169 eyes of 109 control subjects enrolled for 6 months. Four PS position grades were designed. Grade 1 features a grossly vertical PS position. Grades 2 and 3 involve temporal displacement and an abnormal PS tilt. Grade 4 involves PS obliteration with possible associated temporal caruncle dragging. Pterygium corneal encroachment, pterygium fleshiness, and manifest refraction were recorded.


RESULTS
PS position was significantly displaced temporally in pterygium-affected eyes (P = 2 x 10(-4)). Corneal encroachment (P = 2.1 x 10(-5)), pterygium fleshiness (P = 2.7 x 10(-5)), and age (P = 1.3 x 10(-2)) were positively correlated with PS position grades > 1. The presence of with-the-rule astigmatism was significantly linked to PS position grades > 1 (P = 0.01).


CONCLUSIONS
Primary nasal pterygia result in PS temporal ectopia, and PS position grades (more than grade 1) are linked to the presence of with-the-rule astigmatism. These findings are consistent with the exertion of tractional forces at both pterygium ends. In eye abduction, medial canthus structures (PS, caruncule) may be dragged temporally. Thus, pterygium-related corneal traction may not always significantly increase in eye abduction. PS temporal ectopia may influence the decision to remove PS during pterygium surgical excision.
Denion
Eric
E
Ophthalmology Department, Cayenne Hospital, Rue des Flamboyants, Cayenne, French Guiana. edenion@wanadoo.fr
Chambaz
Antoine
A
Dalens
Pierre-Henri
PH
Petitbon
Jean
J
Gérard
Max
M
D000368:Aged; D001251:Astigmatism / Q000209:etiology*; D003286:Contracture / Q000209:etiology*; D003315:Cornea / Q000002:abnormalities*; D019781:Corneal Topography; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011625:Pterygium / Q000150:complications*