This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Conjunctiva, Subject name: Ophthalmology
What is the most common problem following surgical treament of pterygium? 
Select and explain. 
A. Recurrence, B. Corneal ulceration, C. Astigmatism, D. Scleral scarring
A: Recurrence
Answer: A: Recurrence 
Explanation: Recurrence of the pterygium after surgical excision is the most comon problem after pterigium excision and is seen in 30-50 % of the cases. Reference : AK Khurana 7th edition page.89