This patient has a complex ocular history which includes a high degree of axial myopia which was treated with LASIK many years ago. This left eye then developed corneal ectasia and irregular astigmatism so another surgery to insert a plastic intra-stromal ring segment was performed to help bolster the cornea. This helped convert much of the irregular astigmatism to a more symmetric and regular pattern which was then partially treated with PRK. Now the patient presents with a modest cataract but an uncorrected vision of 20/400. in this left eye while the right eye is about 20/30 vision. There is a large refractive error in the left eye of +3.00 -4.00 x 157 which gives about 20/40 vision and the steep axis of corneal astigmatism is 67 degrees. This video shows how the best way to help this patient is to perform cataract surgery and implant a toric monofocal IOL with a goal of about plano. How do you calculate the IOL power? All explained in the video.
