Refractive Lensectomy
Introduction
Cataract surgery used to be a procedure for elderly people who could no longer see well. Technical advances have recently allowed younger patients to consider a new type of elective procedure: Refractive Lensectomy. This is just like cataract surgery, but the procedure is performed on the clear lens of a younger patient. The clear lens is removed and replaced with an artificial lens. Refractive Lensectomy is an elective procedure for which you pay cash. The current market for Refractive Lensectomy is mainly patients between 40-65 years of age.
In this page, we will go through the things that may push you towards considering this procedure, and the reasons you may wish to be cautious. When you are done with this page, you will be empowered to make your own personal decisions about elective Refractive Lensectomy in cooperation with your surgeon.
Why Consider Refractive Lensectomy?
Refractive Lensectomy treats three common refractive issues:
1. Spherical Refractive Error (nearsightedness and farsightedness)
2. Astigmatism
3. Presbyopia
Let's look at each of these issues individually:
1. Spherical Refractive Error: Nearsightedness is an example of spherical refractive error. When you are nearsighted, you see best at near and you cannot see well at distance unless you wear glasses or contact lenses. With higher levels of nearsightedness, glasses can be heavy, can distort images, and can make things look smaller.
2. Astigmatism: Astigmatism is present when the eye focuses light differently in different dimensions. Astigmatism can be treated with glasses, but distortion occurs. Images can look elongated or squished. Contacts can also treat astigmatism, but they often rotate when you blink, causing intermittent blurring.
3. Presbyopia: Presbyopia is the loss of ability to accommodate to near vision. If you need bifocals or readers, you have presbyopia. Presbyopia becomes important to your daily experience sometime in your 40's.
The goal of refractive lensectomy is to minimize the effect of each of the refractive issues above.
What percentage of people over age 50 have these refractive issues?
Significant spherical error: (enough to require glasses or contacts): 60 %
Significant astigmatism: (enough to require glasses or contacts): 70 %
Significant Presbyopia: (enough to require readers or bifocals): 100%
You can see from these numbers that the majority of us over age 50 or so have enough spherical refractive error and/or astigmatism to benefit from refractive lensectomy. If you add in presbyopia, the number climbs to 100%.
How Well does Refractive Lensectomy Work?
When it comes to spherical error and astigmatism, the answer is: really well. There is a basic principle of optics at play here: The closer you get to the lens inside the eye, the better the treatment of refractive issues and the less the side effects. Thus, glasses cause significant distortion and change in image size if you have high refractive error because they are far from the center of the eye. Contacts, which move the correction closer to the center of the eye, cause less distortion and less change in image size. That's why highly nearsighted people prefer contact lenses over glasses.
You can't get any closer to the center of the optical system than by removing the natural lens itself and treating the problem right there with an artificial intraocular lens. So if we just look at the optics, refractive lensectomy is potentially superior to glasses and contact lenses, particularly for people with significant nearsightedness, farsightedness, and and especially astigmatism. This brings us to the first key point:
1. Refractive Lensectomy is potentially an optically superior way to treat
nearsightedness, farsightedness, and astigmatism.
What about presbyopia? The treatment of presbyopia using artificial lenses is less than perfect. Several different strategies are used, but none of them work as well as the natural accommodation you had when you were young. Presbyopia can be treated using bifocal and trifocal intraocular lenses, lenses with extended depth of focus, , lenses that move slightly back and forth inside the eye, and monovision or mini monovision refractive strategies.
Treating presbyopia with multifocal lenses is associated with two important side effects: halos, and loss of contrast. These are simulated below:
Halos
Loss of Contrast
Monovision strategies get around the issues of halos and contrast, but require loss of stereo vision because the eyes no longer focus together. Monovision is well tolerated by some people, and can be considered if you have a history of using monovision contact lenses.
In summary:
2. Refractive Lensectomy provides adequate
but not superior treatment of presbyopia, and is associated with side effects.
These can include glare, halos, loss of contrast, and loss of stereo vision.
Is Refractive Lensectomy Safe?
Next, let's turn our attention to the procedure itself. Refractive lensectomy is basically cataract surgery performed on young people with clear lenses. Over the last few decades, lensectomy surgery has developed into a highly refined, low risk procedure which typically takes minutes to do and involves minimal discomfort. Improvement of vision is evident often with a day. There is good reason for its popularity with elderly patients. For a more detailed discussion of the risks of cataract surgery, take a look at the page Complications of Cataract Surgery.
There is one very curious thing about lensectomy in younger people. It turns out that retinal detachment is much more common after cataract surgery in younger patients. This is demonstrated in the bar graph below:
Source: Incidence of Retinal Detachment after Cataract Surgery
NCBI 2012
Note that over 2% of patients in their 50's experienced a retinal detachment after cataract surgery in this 2012 study. Retinal detachment is also much more common after cataract surgery in highly nearsighted patients of any age.
Unfortunately this means that the very people who are most likely to benefit from refractive lensectomy- highly nearsighted patients in their 50's- are also the most likely to suffer a retinal detachment after lensectomy. In summary;
3. Patients in their 50's undergoing refractive lensectomy
are at risk for retinal detachment
Final Thoughts
An additional consideration is whether you want to have this procedure now versus sometime in the future.
The treatment of presbyopia with artificial lenses is still evolving. It is hard to predict how fast the field will advance, but it is likely that the treatment of presbyopia with lensectomy will work better 10 years in the future than it does now.
Putting it all together: Refractive Lensectomy provides treatments nearsightedness, farsightedness, and astigmatism. Correction of these refractive issues is potentially superior optically to glasses and contact lenses. Treatment of presbyopia is associated with halos and loss of contrast. Refractive Lensectomy can cause retinal detachment. The risk is particularly high for patients in their 50's. Nearsightedness further increases the risk. The treatment of presbyopia with Refractive Lensectomy will continue to evolve.