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Specialized LASIK Eye Surgery with Monovision by Gen Wright

Monovision offers an alternative solution, either through contact lenses or refractive surgery. Monovision eliminates the requirement of dual glasses by correcting individual eyes to different focal lengths. Normally, the dominant eye is focused for distance and the non-dominate eye is corrected for viewing closer images. Monovision works by tricking the brain into believing that the contact lens is a part of the actual eye. Depending on their lifestyle and needs, patients can choose whether to correct both eyes for distance or blend their vision by having one eye corrected for distance sight and the other for near sight.

As the crystalline lenses of the eyes age, their capacity to focus (accommodate) at different distances naturally weakens and is sometimes lost. The result is a treatable condition known as Presbyopia, usually developing between the ages of 40-50.

Presbyopia patients are unable to maintain focus on either near or distant objects and need glasses to help accommodate for their weaker focal length. The most common course of correction for Presbyopia is through bifocal glasses or through separate glasses with varying focal lengths to accommodate for both near and distance vision.

Monovision offers an alternative solution, either through contact lenses or refractive surgery. Monovision eliminates the requirement of dual glasses by correcting individual eyes to different focal lengths. Normally, the dominant eye is focused for distance and the non-dominate eye is corrected for viewing closer images. Monovision works by tricking the brain into believing that the contact lens is a part of the actual eye. Depending on their lifestyle and needs, patients can choose whether to correct both eyes for distance or blend their vision by having one eye corrected for distance sight and the other for near sight.

Eye dominance is established by which eye works slightly harder than the other and is very simple to determine. To verify which eye is dominant: keep both eyes open, hold out a thumb at eye level and block either an object or a word in the line of site with the thumb. Close one eye and then close the other. The dominant eye is the one that did not see the object or word.

Nearsighted adults, who use glasses to help see distant images, tend to be capable of up-close reading without glasses. By giving them 20/20 distance vision, they will lose their ability to adjust focal lengths and focus. These individuals will then likely need glasses for reading. It is important to realize that Monovision is meant to give you functional, not perfect, vision.

LASIK with Monovision is a breakthrough technology for Presbyopia treatment. Instead of relying on glasses or contacts to accomplish Monovision, surgeons strive to permanently achieve the same results through a customized LASIK procedure.

A great option for undecided LASIK with Monovision candidates is to consult with eyecare professionals and sample contact lenses that will deliver comparable results to the surgical process. Keep in mind that the brain will need an adjustment period to relearn which eye is ideal for different tasks.

To ensure the ultimate results, LASIK surgeons will always include a discussion of Monovision during pre-surgical consultations of candidates over the age of 40 who use bifocals or reading glasses to treat their Presbyopia.

Patients over 50 who choose not to include Monovision in their LASIK procedure will likely need reading glasses post-LASIK surgery. Lens Replacement Surgery is a possible alternative for patients over 50 who want to correct both near and distance vision, without a dependence on glasses or incorporating Monovision.

For more information, speak with your eye-care professional.

LasikSurgeryRX is a consumer resource with information on Lasik and Cost of Lasik and much more.

Article Source: http://www.earticlesonline.com/Article/Specialized-LASIK-Eye-Surgery-with-Monovision/416807

How do you calculate the focal length of a convex/converging lens?

I bought two lenses that are different sizes. Now I have to calculate their focal length. I think I'm supposed to use either the thin lens equation (1/f = 1/di + 1/do) or the magnification equation (M = hi/ho = -di/do) or both.

Should I do some sort of experiment to calculate all these lengths? If yes, then can you explain how I should do this experiment? Thanks!

Using sphero-meter measure their radii and find out the refractive index of the material
use the formula 1/f = (mu-1)(1/r1 - 1/R2)
Or focus the image of a distant object on a screen and measure the distance of the screen from the lens to get the focal length.

You can also use two pin method with an optical bench to find f by UV method and using the phenomenon of parallax.

Tags: camera, focal, focal length, focal length calculator, focal length comparison, focal length definition, focal length multiplier, lens, photography, reference

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