PAX6 and pterygium: To systematically investigate whether there are commonalities in gene expression regarding transcription factors PAX6 and TP63, adhesion markers, keratins, markers regarding the retinoic acid metabolism, and microRNAs 138-5p and miR-204-5p, we analyzed gene expression in conjunctival impression cytology samples of patients with EBMD, SND, pterygium, and congenital aniridia and healthy controls and corneal epithelial samples of patients with EBMD, SND, pterygium, and healthy controls.