A pterygium reduces
vision in several ways: • Distortion of the
corneal optics. This begins usually when the pterygium is greater than 2mm from the
corneal limbus. • Disruption of the
tear. The tear film is the first lens in the eye. Pterygia are associated with eyelid inflammation, called
blepharitis. • Growth over the corneal centre, which leads to dramatic reduction of vision. • Induced anterior corneal scarring, which often remains after surgical removal. A pterygium of the eye grows very slowly. Usually it takes several years or decades to progress.
Surgical removal Indications for surgery, in order of decreasing importance: • Growth over the corneal centre. • Reduced vision due to corneal distortion. • Documented growth. • Symptoms of discomfort. •
Cosmesis. Surgery is usually performed under
local anaesthetic with light sedation as day surgery. The pterygium is stripped carefully off the surface of the eye. If this is all that is done, the pterygium regrows frequently. The technique with the lowest recurrence rate uses an
autotransplantation of
conjunctiva from under the
eyelid. This is placed over the defect remaining from the removed pterygium. The graft can be stitched in place, which is time-consuming, and painful for the patient afterwards. An alternative is the use of tissue adhesive
fibrin glue. A
Cochrane review including 14 studies and last updated October 2016, found that using fibrin glue when doing conjunctival autografting was associated with a reduced likelihood of the pterygium recurring compared with
sutures. The review found that operations may take less time but fibrin glue may be associated with more complications (for example, rupture, shrinking, inflammation,
granuloma). A 3-year clinical study on the application of
collagen matrix as excision site grafts showed significantly improved surgery success rates. The mechanism of the collagen matrix graft (commercially available as ologen) works by promoting healthy
cell growth into the matrix, thus preventing
conjunctiva overgrowth that can cover the
iris. == References ==