PURPOSE: To compare the corneal tomographic features of patients with prolactinoma with those of healthy controls and to assess the risk of ectasia in the corneas of patients with prolactinoma. METHODS: Forty-two patients with prolactinoma and 48 controls were included in this study. Keratometry values, thinnest corneal thickness (TCT), maximal anterior and posterior elevation values, front and back difference elevation, average and maximum pachymetric progression index (PPIavg and PPImax), maximum Ambrósio relational thickness (ARTmax), Final D, and corneal densitometry parameters were recorded using corneal tomography with the Pentacam AXL wave. RESULTS: Patients with prolactinoma exhibited significantly higher steep K (K2), maximal anterior and posterior elevations, and significantly thinner TCT values than the control group ( P = 0.039, P = 0.006, P < 0.001, and P = 0.003). The differences in front and back elevations, PPIavg, PPImax, and Final D were all significantly higher, whereas the ARTmax was significantly lower (all P < 0.05). Central density values were also notably higher in the 0-2 mm central area, 2-6 mm annular area, and entire diameter area ( P = 0.009, P = 0.008, and P = 0.045, respectively). When examining factors that affected the final D in patients with prolactinoma, age, prolactin levels at diagnosis, prolactin levels on the day of examination, duration of hyperprolactinemia, and FSH levels all showed significant effects in the univariate analysis (β = 0.048, P = 0.004; β = 0.005, P = 0.005; β = 0.006, P = 0.004; β = 0.028, P < 0.001; and β = 0.071, P = 0.009, respectively). In multivariate analysis, the duration of hyperprolactinemia also had a significant impact (β = 0.020, P = 0.022). CONCLUSIONS: The risk of ectasia may increase with prolonged elevation of prolactin levels in patients with prolactinoma.