Final answer:
After cataract surgery, whether a patient needs glasses or contact lenses depends on the type of intraocular lens implanted and the patient's visual requirements. Presbyopic patients (those who struggle with reading up-close) might require reading glasses following surgery with a monofocal IOL. The power of the IOL for myopic patients is generally less than their natural lens to correct vision.
Step-by-step explanation:
After cataract surgery, where a cataract-clouded lens is replaced with an intraocular lens (IOL), the need for glasses or contacts depends on the type of IOL used and the patient's visual needs. If an IOL is chosen to give perfect distant vision, the patient might still need glasses for reading or up-close work, assuming the IOL does not have multifocal capabilities. This scenario is common if the IOL used is monofocal. For clients who were nearsighted before surgery, the power of the intraocular lens would generally be less than that of their natural lens to correct the vision.
When it comes to myopia, or nearsightedness, adjustment of the cornea's curvature during surgery is required. To correct myopia, the cornea's curvature would be made smaller, flattening it to decrease the refractive power. Conversely, for hyperopia (farsightedness), the curvature would be made greater to increase the eye's focusing power. Glasses with around 16 D are prescribed post-cataract surgery if no IOL is implanted because the natural lens, which typically has a power of approximately 16 diopters, is removed.