Corneal Changes With Pentacam Before and After Pterygium

Pterygium is a dysplasia of the bulbar conjunctiva extending onto the corneal surface. The prevelance of pterygium ranges from 0.7% to 31% in various populations according to the location, altitude, and race. It has a higher prevelance in areas which have increased exposure to direct sun with ultraviolet (UV) B light. Patients with pterygia present with variety of complaints ,ranging from asymptomatic to significant redness ,swelling ,itching ,irritation and blurring of vision associated with elevated lesions of the conjunctiva and contiguous cornea in one or both eyes.The induction of astigmatism due to the invasion of the pterygium into the cornea as well as changes in corneal curvature and refractive status has been reported by numerous studies.

Multiple different procedures have been advocated in the treatment of pterygia. These procedures range from simple excision to sliding flaps of conjunctiva with or without adjunctive external beta radiation therapy and/or use of topical chemotherapeutic agents, such as Mitomycin C.

Pentacam is a rotating Scheimpflug camera which measures Scheimpflug images of the anterior eye segment. With the pentacam, topographic analysis of the corneal front and back surfaces is based on the true elevation measurement from one side of the cornea to the other (limbus to limbus). Pentacam also describes the true thickness of the cornea across its entire breadth and width.

Type of the study: prospective observational longitudinal study

Study Setting: Assuit University Hospital ( ophthalmology Department ) Assuit Police Hospital ( ophthalmology Department )

Study subjects:

1. Inclusion criteria:

   • The study will include 30 eyes of adult subjects.
   • All eyes have primary pterygium and seeking for surgery due to Cosmetic problems, ocular irritation, and, or visual impairment.
   • All selected patients will undergo complete ophthalmological examination including refraction, best corrected visual acuity, keratometry, and pentacam (scheimpflug imaging) preoperatively then will be followed up 2 and 6 months post pterygium excision.

2. Exclusion criteria:

   • patients with recurrent pterygium.

   • Patients with media opacities:

     • Dense cataract. - Corneal opacities.
   • Patients with a history of intraocular surgery ,ocular trauma ,and contact lens wear.
   • Patients with severe ocular surface disorders as Stevens-Johnson syndrome.