Hi Thanks for your query. I appreciate your concern for your son. The features described in your query are suggestive of a fleshy benign growth that starts in the white portion of the eye near the nasal area and referred to as Pterygium. Since your son has been spending a lot of time on out door activities, the following risk factors might be responsible Environmental factors like increased exposure to ultraviolet rays (sun light), winds, dust, a family history (genetic) of such growth. He needs to be observed unless the growth reaches the center of the cornea or he shows intense redness, discomfort, or alterations in visual function. Use of sunglasses or avoiding playing under the sunlight or during strong winds can prevent the further growth of the pterygium. Treatment is usually not required. Using artificial tears to keep the eyes moist may help prevent a pterygium from becoming inflamed. Pterygium can be removed for cosmetic reasons or if affects the vision. Hope this answers your query. Rate this answer, if you are convinced.