Efficacy and Safety of PRO-155 on Inflammation of the Conjunctival Surface in Subjects With Grade I-III Pterygium vs Placebo.

Inclusion Criteria: * Age of 18 to 90 years. * Both genders. * Clinical diagnosis of grade I to III pterygium (temporal, nasal, or bitemporal). * Possibility of going to the revisions when indicated. Exclusion Criteria: * Subjects with topical or systemic medication that interfere decisively in the results of the study; such as topical immunomodulators, NSAIDs, antihistamines, corticosteroids, artificial tears with conservative, vasoconstrictors etc. * Subjects (female) with active sexual life who do not use a contraceptive method. * Subjects of the female sex in a pregnant state or who are breastfeeding. * Subjects of the female sex with pregnancy test in positive urine. * Positive substance abuse * Subjects who have participated in any clinical research study in the last 40 days. * Subjects legally or mentally incapacitated to give their informed consent for their participation in this study. * Subjects that can not comply with the appointments or with all the requirements of the Protocol.