Glaucoma Filtration Surgery
The most common conventional surgery performed for glaucoma is the trabeculectomy. A partial thickness flap is made in the scleral wall of the eye and a window opening is made under the flap to remove a portion of the trabecular meshwork.
The scleral flap is then sutured loosely back in place to allow fluid to flow out of the eye through this opening, resulting in lowered intraocular pressure and the formation of a bleb or fluid bubble on the surface of the eye.
Scarring can occur around or over the flap opening, causing it to become less effective or lose effectiveness altogether. Traditionally, chemotherapeutic adjuvants, such as mitomycin C (MMC) or 5-fluorouracil (5-FU), are applied with soaked sponges on the wound bed to prevent filtering blebs from scarring by inhibiting fibroblast proliferation. Contemporary alternatives to prevent the scarring of the meshwork opening include the sole or combinative implementation of nonchemotherapeutic adjuvants such as the ologen collagen matrix, which has been clinically shown to increase the success rates of surgical treatment. The collagen matrix prevents scarring by randomizing and modulating fibroblast proliferation in addition to mechanically preventing wound contraction and adhesion.
Pterygium most often refers to a benign growth of the conjunctiva. A pterygium commonly grows from the nasal side of the conjunctiva. It is usually present in the palpebral fissure. It is associated with and thought to be caused by ultraviolet light exposure (e.g., sunlight).
The predominance of pterygia on the nasal side is possibly a result of the sun’s rays passing laterally through the cornea, where it undergoes refraction and becomes focused on the limbic area.
Sunlight passes unobstructed from the lateral side of the eye, focusing on the medial limbus after passing through the cornea. On the contralateral (medial) side, however, the shadow of the nose medially reduces the intensity of sunlight focused on the lateral/temporal limbus.