Refractive Lensectomy? Maybe.
Introduction Technical advances in cataract surgery 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, typically 40-60 years old. The clear lens is removed and replaced with an artificial lens. In this blog post, I will help you understand why you might be enthusiastic about this, and why you might be cautious. This post will empower you to make your own personal decisions about this elective procedure. 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, intraocular 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/Starbursts
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. This brings us to the second important consideration: 2. The treatment of presbyopia with refractive lensectomy may be 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 usually evident often with a day. There is good reason for its popularity with elderly patients. Whether you call it cataract surgery or refractive lensectomy, removal of the lens is surgery, and all surgeries can have complications. For a detailed discussion of the risks of refractive lensectomy, take a look at the page Complications of Cataract Surgery on my website. 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. Younger patients are actually much more likely to experience this complication than elderly patients. This is because the vitreous gel- the clear material in side the eye- is different in younger people, and it can pull on the retina during the procedure. The graph below shows how the risk of retinal detachment after lensectomy varies with age. Notice that patients in their 50's are at the highest risk.
Source: Incidence of Retinal Detachment after Cataract Surgery NCBI 2012 In this 2012 study, over 2% of patients in their 50's experienced a retinal detachment after cataract surgery. Retinal detachment is also much more common after cataract surgery in highly nearsighted patients at 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. This brings us to the third important consideration: 3. Patients in their 50's are at risk for retinal detachment if they undergo lensectomy
Final Thoughts Finally, you should ask whether you want to have this procedure now versus sometime in the future. This decision may hinge on how you feel about presbyopia. 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 treatment for nearsightedness, farsightedness, and astigmatism that is potentially optically superior to glasses and contact lenses. Treatment of presbyopia with Refractive Lensectomy is associated with side effects including halos and loss of contrast. The treatment of presbyopia is still evolving. Refractive Lensectomy can cause retinal detachment. The risk is particularly high for patients in their 50's, especially nearsighted patients.
Seattle based surgeon Christopher A. Kuntz MD has performed over 10,000 cataract surgical cases over the last 25 years. He is the principal author of www.cataractsurgerydesign.com, an international free website that helps patients make their best decisions before, during and after their cataract surgery.
