BackgroundCorneal ectatic diseases are a group of corneal disorder characterized by the steepening and thinning of the cornea. Older people are not a high-risk population for corneal ectatic diseases; due to the lack of typical preoperative topographic manifestations, there is a high possibility that corneal ectasia is undetected.Case presentationTwo patients with subclinical corneal ectasia and senile cataracts presented with irregular astigmatism after steep-axis incision during cataract surgery. The two cases presented in this case report are rare because both patients experienced tremendous changes in astigmatism after cataract surgery.ConclusionThis case report may shed some light on astigmatism-correcting steep-axis incisions in cataract surgeries.