Several papers have reported as many as 10% of pterygia having foci of CIN—interestingly, none of these 10% were clinically recognized preoperatively,” Dr. Perry says. “Therefore, clinical photos are helpful, and performing a conjunctival scraping with a Kimura spatula and putting the material on a glass slide may be diagnostic.” Put the slide in a Coplin jar with methanol and send to a cytologist for evaluation.