Cancer The<unk>  is a common site for the occurrence of<unk>  epithelial neoplasm. Aniridia Aniridia, a developmental anomaly of the iris, disrupts the normal barrier of the<unk> to the conjunctival epithelial cells at the<unk> . Glaucoma The<unk>  may be cut to allow for aqueous humour to drain from the anterior chamber of the eye into the subconjunctival space. This can be used in glaucoma treatment. The hole created only needs to be small, although slightly bigger than needed to account for gradual healing. This procedure sometimes fails, particularly if the hole is large. It can lead to eye irritation from blebbing. Trabeculectomy, a surgery used to treat glaucoma, is best performed with an incision through the superior part of the<unk> . Mattress suturing may be used to close this incision.
Corneal limbus
Corneal button
Optic cup 
Scleral lens
Optic pit
Lacrimal groove
Optic recess
Iris pigment epithelium