PURPOSE: To evaluate chorioretinal vascular changes in patients with keratoconus using optical coherence tomography angiography. METHODS: This mixed retrospective-prospective clinical study was conducted at University Eye Hospital in Heidelberg, Germany. A total of 184 eyes of 128 patients with keratoconus, 12 eyes with forme fruste keratoconus, and 100 eyes of 53 healthy control patients underwent comprehensive ocular examinations. Key parameters included corrected distance visual acuity, slit-lamp biomicroscopy, corneal tomography, and biomechanics. Assessed parameters included anterior/posterior radii of curvature, thinnest corneal thickness, maximum anterior sagittal curvature, flat/steep axis keratometric value, Belin/Ambrósio Enhanced Ectasia Deviation index, Tomographic Biomechanical Index, Corvis Biomechanical Index, Corvis Biomechanical Factor, E-staging, central macular thickness, and vessel density (VD) of the macular superficial capillary plexus (mSCP), macular deep capillary plexus (mDCP), and macular choriocapillaris. Keratoconus severity was classified using the ABCD grading system. RESULTS: In the keratoconus group, there was a significant increase in VD in the mSCP group (83.9 ± 4.04%) and the mDCP group (76.98 ± 5.5%) compared to the control group (mSCP: 78.29 ± 3.79%, mDCP: 71.07 ± 3.84%) (P < .00055 for both). These changes showed significant correlations with various clinical parameters, including the sum of the ABCD staging system (Rho = 0.33 for mSCP VD; Rho = 0.44 for mDCP VD). CONCLUSIONS: This study revealed that macular SCP and DCP VDs are significantly increased in patients with keratoconus. Such vascular changes suggest an inflammatory component in keratoconus pathophysiology.