Aberrations and your Vision
You just had an eye exam but you still can’t see as well as you would like out of the new prescription. The Optometrist checked your prescription again and everything checks out just fine, but you still are having difficulties seeing properly. Your Eye Doctor may adjust the prescription slightly and you receive the new prescription but it still seems out of focus. Then you may have a high order optical aberration. Optical aberrations cause distortion in the image by an optical system. The Human Eye is an optical system. Some symptoms are difficulty seeing at night, glare, halos, blurring, starburst patterns or double vision. No eye is perfect so all eyes have some sort of high order aberration. In mild cases of these you won’t be affected. In the above diagram perfect vision would be on a flat plane or green color just like the piston picture. The red or blue colors represents severe aberrations. There are two categories. Low order and high order aberrations. Low order aberrations are generally easy to correct. High order aberrations are more difficult to diagnose and treat. They can occur whether you have single vision or need multifocal lenses. Here’s a general description of the two categories.
Low order Aberrations
Low order aberrations are refractive errors such as myopia (nearsighted), Hyperopia (Farsighted) or Astigmatism and they can be determined during an eye exam. These usually are corrected with standard eyeglass lenses unless you have a significant amount. Then you would want to consider options such as a high index lens (thinner lens), aspheric lenses, or polycarbonate lens. Each one of these types have different properties to aid in your visual acuity since they are generally flatter and thus should help. There are different coatings we like to apply to aid in clarity such as an anti reflective coating. This coating reduces glare, improves night vision and the effects of aberrations. You just had an eye exam, filled your eyeglass prescription but you are still having difficulty focusing. Then you may have a high order aberration.
High order Aberrations
A higher order aberration results in a distorted image when you have irregularities in one or more of the refractive parts of the eye. This includes the tears or dry eyes, cornea, aqueous humor, crystalline lens and the vitreous humor. These are all structures with in the eye that light passes thru to the retina to allow you to see clearly. If any of these structures have any distortion or irregularities then it will cause distortion. Abnormal curvature of the cornea and crystalline lens may contribute to to this distortion. Serious higher order aberrations can be caused by any scarring of the cornea, lasik eye surgery or trauma. These higher order aberrations are directly proportional to your pupil size. So the larger your pupils the more distortion you might have. This is especially true at night since your pupils are larger or more dilated at night. There are quite a few different types. Some of the most common aberrations are Prism, Astigmatism, Coma, Spherical and Chromatic Aberration.
Treatment for Aberrations or Distortion
We can detect these types of aberrations here during an eye exam at EyeMechanix. It can be a challenge to correct for these types of distortion but once it is corrected it’s pretty amazing. Approximately 15-20 percent of all individuals have these high order aberrations that affect their vision, but typically they go undiagnosed. I just detected a patient with a coma aberration. He previously had issues with every pair of eyeglasses. Now he said the vision out the new lenses is so clear that he can’t believe he can see this well and no more of the “swimming effect” he had before. We generally use a high definition or other special lenses in our eyeglasses to reduce the effects of these curves to aid in clarity. You may also correct these aberrations with contact lenses. Hopefully this may help some of you explain difficulties with your vision. So if you feel even the best correction isn’t good enough schedule an eye exam here in our Eye Care Center and we can determine if you have optical aberrations.
Schedule an appointment today with our Lincoln Park Eye Doctor and SEE the difference!