Corneal Topographic Changes in a Case of Limbal Conjunctival Carcinoma

Abstract

The similarity with the patterns induced by pterygia, the lack of corneal infiltration, and the complete reversal of astigmatism after excision support the theory that tear pooling at the tumor apex is responsible for secondary astigmatism and diffuse corneal flattening. However, the irregularity induced by the tumor may affect the precision of topographic measurements.

Physiology of Astigmatism

“…The superior eyelid exerts pressure on the cornea, and tear accumulates over the lower eyelid margin due to gravity; this combination induces a vertical coma which may manifest as a cylinder (Montés-Micó et al, 2004a). Localized aggregation of lacrimal fluid is also caused by peripheral corneal lesions such as pterygium (Oldenburg et al, 1990;Walland et al, 1994;Yasar et al, 2003), limbal conjunctival carcinoma (Leccisotti, 2005), or nodules (Das et al, 2005). Such changes cause corneal astigmatism and are largely resolved after excision of the lesion or drying of the tear pool (Leccisotti, 2005;Yasar et al, 2003).…”

Prospective Study of Exclusive Strontium-/Yttrium-90 β-Irradiation of Primary and Recurrent Pterygia with No Prior Surgical Excision

“…Clinically, the progression of this lesion demonstrates a great impact on the cornea morphology and shape inducing corneal and refractive astigmatism by flattening localized areas central to their apex [13,14,26,35,42]. The pterygium was also found to induce significant amount of regular and irregular astigmatism according to its size [5,24,26,29,31,32,41,43] and various complications like tear pooling, a feature found also in cases of limbal conjunctival carcinomas [14,26], were also correlated to pterygium proliferation.…”

“…The pterygium was also found to induce significant amount of regular and irregular astigmatism according to its size [5,24,26,29,31,32,41,43] and various complications like tear pooling, a feature found also in cases of limbal conjunctival carcinomas [14,26], were also correlated to pterygium proliferation.…”