Purpose: To assess the corneal topographic changes pre and post excision of primary pterygium and to assess the collaboration between the size of the pterygium and these changes which obtained by Pentacam. Patients and Methods: This study is prospective, non-randomized, and interventional. It involved 38 eyes of 38 individuals with primary nasal pterygium. The cases were classified into two groups in terms of the size of the pterygium. All patients were managed by surgical excision of pterygium with a bare sclera approach and intraoperative MMC application. Follow-up was done after one, three, and six months postoperatively. The following measu-rements were obtained using Pentacam: K1, K2, astigmatism, axis, anterior elevation map, and apical corneal thickness. Additionally, we studied the changes in UCVA, BCVA, refractive sphere, and cylinder. Results: The mean age of all cases was 56.16±5.1 years (48-64 years). The mean astigmatism decreased significantly from -4.6±3.1 preoperatively to -1.32±0.7 postoperatively. Large sized pterygium group has significant higher astigmatic values preoperatively and postoperatively. The mean K1 increased significantly (p < 0.05) postoperatively, while there was no marked variation in mean K2 during 3 and 6 months postoperatively ( p>0.05). There was an obvious decrease in mean values of the anterior elevation map, apical corneal thickness, refractive sphere, and cylinder postoperatively. Both UCVA and BCVA improved significantly postoperatively. Conclusion: pterygium leads to significant topographic and refractive changes that rise with the elevation in the pterygia size and enhance after pterygium surgery.