I recommend Cheonan Samsung Miracle Eye Clinic.

Before the holiday, my father suddenly lost vision in one eye, so we took him to the local ophthalmology clinic in our hometown. Since it’s a rural area, they told us there was nothing they could do and advised us to go to a university hospital. I contacted them and brought him in first. We went to our family's regular ophthalmology clinic, Samsung Miracle Eye Clinic, and had him examined again to assess his current condition. The doctor explained everything carefully and in detail, including whether treatment was necessary. They scheduled the procedure immediately. Since it coincided with the holiday, the procedure was to be done after the holiday, but the doctor explained everything thoroughly before and after the procedure, including precautions, which made us feel very reassured. If we had gone to a university hospital, it would have taken a lot of time just for the tests, and everything else would have taken even longer. It seems there’s a reason why this hospital is famous in Cheonan.