Refractive Errors

Myopia (Nearsightedness)

Vision is clear up close, but is blurred far away. Patients who are nearsighted may find a negative number in the sphere column of their prescription.

Hyperopia (Farsightedness)

Vision is better far away than close, however both are blurry. Patients who are farsighted will find a positive number in the sphere column of their prescription.


Vision is distorted and blurred in general, both up close and far away. Information regarding astigmatism is found in the cylinder column of your prescription. Many people with myopia or hyperopia have some degree of astigmatism.


Presbyopia is the natural hardening of the lens that occurs as we age, resulting in blurred near vision. This usually starts at about age 40 and tends to stabilize by about age 60. The standard LASIK and PRK procedures do not correct Presbyopia. However, a “blended” or “monovision” procedure – a process by which one eye is corrected for distance vision and the other eye is corrected for intermediate and near vision – is an excellent option for presbyopia. Not everyone is an ideal candidate for Blended or Monovision, so it is important to simulate this type of vision with patients before undergoing the procedure. There are also a variety of lens implants available that can also help correct myopia for patients over the age of 50.

They provide binocular clear distance and near vision in each eye individually (see Cataract lens implants for more information).


May be achieved not only by LASIK or PRK. The dominant (preferred) eye is focused far away, while the non-dominant eye is focused at the reading or computer distance. It is designed to make vision functional, the majority of the time. Most patients can easily adapt to monovision either immediately or within a few weeks. Patients may need to wear glasses to neutralize monovision with some activities like night driving.