Many cataract patients have a combination of refractive errors, including myopia, hyperopia and astigmatism. Traditionally, cataract surgery did not change the shape of the cornea, and therefore the amount of astigmatism. With advances in technology, it is now possible to reduce the amount of astigmatism through surgery. If the patient has a small amount of astigmatism, a special corneal incision can be designed to reduce the amount of astigmatism; if the patient has a large amount of astigmatism, a special type of IOL can be implanted to correct the astigmatism.
If the patient has high hyperopia before surgery, the cataract surgery can reduce the hyperopia or adjust it to a mildly myopic state, so that the patient’s visual experience in daily life will be significantly improved. For patients with high myopia, the surgeon will also design a reasonable post-operative refractive state for the patient to have a better visual experience after surgery, and most patients will be able to remove their heavy myopic glasses that they have used for their whole life after surgery. Patients with high myopia should be reminded that both eyes must be operated within a short period of time. If one eye becomes orthokeratology or mild myopia after surgery, while the other eye is still highly myopic, it will lead to a lack of coordination between the two eyes.
Most of the IOLs used today are monofocal, and usually, the doctor will set the patient to see without glasses at a distance, but with presbyopic glasses at a close distance. If the patient has a special request, the doctor can also set the patient to see near without glasses, but to see far with glasses. If a patient wants to see far and near without glasses, he or she can tell the doctor that a multifocal IOL is available to help him or her do this, but not all patients can use this type of lens, and there are strict indications for using this type of lens that the doctor will recommend based on the patient’s eye exam.