Oh really ? You don't say
"This suggests that AI models may be more sensitive to image quality issues than human beings. "
No kidding. A computer that just might be totally incapable of not taking an image input otherwise than pixel by pixel. What a surprise when said pixels have an inordinate amount of impact on the algorithm's interpretation.
Computers do not see. They take the data they are given. Give them flawed data and the result will be wrong.
If there are so many parameters to take into account to do retina diagnostics, then maybe the tool isn't fit for the job.