有些作者认为,结膜的鳞状细胞癌在非洲比气候温和的地区更常见,提示了这些肿瘤是由前已存在的病变经紫外线长期辐射而发生的。这些病变通常诊断为睑裂斑或翼状胬肉,其特点为靠近角膜缘呈楔形肥厚的混浊,从球结膜可伸展到角膜上。病理组织学通常将这种损害描述为日光性角化病,以及上皮异常或发育不良。作者在非洲马拉维对234例进行结膜活检, Some authors believe that conjunctival squamous cell carcinomas are more common in Africa than in temperate climates, suggesting that these tumors develop from long-term UV exposure of pre-existing lesions. These lesions are commonly diagnosed as palpebral fissures or pterygium characterized by wedge-shaped hypertrophy near the corneal limbus that extends from the conjunctiva to the cornea. Histopathology is commonly described as damage to solar keratosis, as well as epithelial dysplasia or dysplasia. The authors performed 234 conjunctival biopsies in Malawi, Africa,