The diversity and uncertainty of ocular aberrations in abnormal eyes limit the usefulness of adaptive optics in clinical application. Aberrations are characterized in two populations of Chinese abnormal eyes, namely those with glaucoma and those with diabetes retinopathy. Furthermore, the impact of aberrations on retinal image quality and the requirements of wavefront correctors for aberration compensation are analyzed. The results show that higher-order aberrations of glaucoma eyes and diabetes retinopathy eyes are larger than what is typical in normal eyes, approximately 2.9 and 1.8 times respectively. To reach diffraction-limited imaging, correction of Zernike polynomials more than the 8th order is necessary for both glaucoma eyes and diabetes retinopathy eyes and the required corrector Strokes are over 39 μm and 14 μm, respectively. The results presented will help guide the development of wavefront correctors for clinical instrumentation.