The most common procedures carried out on the human eye are laser eye surgery and cataract surgery. They are totally different procedures and usually carried out for different reasons. But they can affect each other, and many people who are thinking about having vision correction surgery have concerns about how laser eye surgery can affect cataracts and vice versa. This article will discuss some of the common concerns people have. But first a brief introduction.
Laser eye surgery
Laser eye surgery procedures such as LASIK, SMILE and PRK involve using special lasers to reshape the cornea, which is the front surface and main focusing component of the eye. They are all carried out entirely on the outer surface of the eye. Laser eye surgery can be used to correct short and long sight, astigmatism and presbyopia.
A cataract is when the lens becomes cloudy. Cataract surgery involves removing this now cloudy lens of the eye. The lens of the eye provides about 40% of the eye’s total focusing power. In younger people it also adjusts the focus for near and far vision. An artificial lens called an Intra-Ocular Lens (IOL) usually replaces the cloudy lens. This compensates for the loss of focusing power caused by removal of the cataract. Many different types of IOLs are available including; monofocal IOLs which can give good vision without glasses at one distance, multifocal IOLs which can give a larger range of clear vision without glasses, and toric IOLs which can correct astigmatism. The surgeon will choose the correct IOL for each patient’s needs. The correct IOL will correct vision and reduce the need for glasses after surgery.
From this, you can see that both laser eye surgery and cataract surgery can be used to correct vision to reduce dependence on glasses or contact lenses for clear vision.
Common Questions About Laser Eye Surgery and Cataracts
Does laser eye surgery cause cataracts?
Laser eye surgery will not cause cataracts to develop at a younger age. If you are going to develop cataracts as you get older, it will happen whether or not you have had laser eye surgery.
The lasers work by using ultraviolet or infrared light to reshape the cornea and correct vision. Neither of these types of light penetrate through the cornea into the interior of the eye. Therefore they are incapable of causing a cataract to develop, or to progress if one is already present.
Does laser eye surgery interfere with me having cataract surgery when I am older?
No, laser surgery does not interfere in any way with having cataract surgery later on, if you need it.
The normal lens in the eye is removed during cataract surgery and replaced with an artificial lens called an IOL. A device, called an optical biometer, measures the eye. This calculates the correct power of IOL. Part of this calculation involves measuring the curvature of the cornea which is reshaped with laser eye surgery such as LASIK or SMILE. Previously, the reshaped cornea interfered with the calculations made by the biometer, often resulting in “refractive surprises”. The interference introduced inaccuracies and errors in the choice of IOL. However in recent years, we have a better understanding of why this occurs and we also have better biometers which can compensate for corneas which have been reshaped by LASIK or SMILE. Now choosing a suitable IOL for someone who has had laser eye surgery is just as accurate as it is for someone who has never had laser eye surgery.
Can I have laser eye surgery if I am developing cataracts?
In theory you could do so, however, it is not recommended. During your medical assessment for laser eye surgery your eyes will be checked for signs of developing cataracts. Your surgeon will recommend that you do not proceed, even if it’s early signs. The reason being, as a cataract progresses, it will cause changes in your vision that will affect the outcome of your laser eye surgery. A worsening cataract can cause the eye to become increasingly short sighted, and cause a general deterioration in vision quality. We cannot tell how quickly a cataract will progress to the point where it affects vision or how. But in some cases, this can occur within only a few years. If you have recently spent a significant amount of money having laser eye surgery, you are likely to be very annoyed if within a couple of years your vision deteriorates due to cataracts.
Your surgeon may offer you “cataract surgery” if there are signs of cataracts. Also known as “refractive lens exchange” (RLE) or “clear lens exchange” (CLE), as an alternative way of getting out of glasses or contact lenses.
Refractive Lens Exchange
This is quite different from cataract surgery in an elderly person, their vision is usually significantly compromised and cannot be fully corrected with glasses. Someone who is found to have early cataracts during their laser eye surgery assessment is likely to be a bit younger than the average cataract surgery patient. They will also have good corrected vision with glasses or contact lenses.
The procedure of refractive lens exchange surgery is identical to standard cataract surgery however. The chosen IOL will correct your vision, just as laser eye surgery would have. The lens of the eye, containing the developing cataract, is removed during the surgery. Therefore you will not develop a cataract in the future and your vision should not change in the future.
Why not do refractive lens exchange (RLE) on everyone who wants vision correction surgery?
This sounds like a reasonable idea at first glance. If you have RLE surgery, your vision will not change in the future and you will not develop cataracts. In fact, many eye surgeons will offer RLE to patients over the age of 45 who wants out of glasses; whether or not they have signs of cataracts. The usual reasoning being: one procedure, no more cataracts and a lifelong solution to vision correction.
I strongly disagree with this approach for two reasons – cost and risk. If someone has early cataracts at any age and is keen to reduce their dependence on corrective lenses, then it is quite reasonable to carry out our RLE. If they have been fully informed about the risks and benefits of doing so. However, refractive lens exchange has significant additional risks, and is substantially more expensive than laser eye surgery. For these reason, I do not recommend RLE for someone who does not have signs of cataracts.
The most important concern when choosing between laser eye surgery and RLE is the additional risk associated with refractive lens exchange. Laser eye surgery has low risk and complications. The worst complication that can occur following laser eye surgery is to develop a serious corneal infection. In the worst case this could result in corneal scarring and significant damage to vision, requiring a corneal transplant. However, it is extremely unlikely that permanent loss of vision could occur. The risk of infection following laser eye surgery is approximately 1 in 5000 cases.
By contrast the two worst complications which can occur following RLE are: an intraocular infection or a retinal detachment. The risk of infection is approximately 1 in 2000 cases, which is two and a half times more than laser eye surgery. While an infection after RLE can usually be treated, significant permanent and irreversible loss of vision can occur. Even with successful treatment. A retinal detachment occurring after RLE can also usually be treated, but is not always completely successful. In some cases, as with an infection, permanent and irreversible loss of vision can occur. The risk of a retinal detachment occurring after RLE varies for different individuals, but can be up to one in 1500 cases.
Because refractive lens exchange require an operating theatre, more staff and different equipment, it can cost up to 50 percent more than laser eye surgery. The cost of laser eye surgery is between $3050 and $3580 per eye in New Zealand. Whilst the cost of refractive lens exchange can be between $4000 and $5000. The type of lens used and which surgeon are both factors in the cost variation.
Deciding to have any type of vision correction surgery is an important and serious decision. It is especially important that you are fully informed of the risks associated. Where possible, you should always choose the safest procedure which is suitable for you.
Do people ever have laser eye surgery after having cataract surgery?
Laser eye surgery is sometimes carried out on people who have had cataract surgery. The reason for doing this is usually that the vision has not been fully corrected by the cataract surgery. This can mean that the person’s eye is short or longsighted or has astigmatism, resulting in less than optimal vision. This problem can often be corrected by exchanging the original IOL for a different lens which fully corrects the vision in the affected eye. In some cases, however, it is not possible or appropriate to carry out an IOL exchange. In this situation, laser eye surgery can be highly effective at correcting the vision. The results are generally just as good as what is achieved in those who’ve not had cataract surgery.
To find out more about laser eye surgery at the Wellington Eye Centre and whether you’re suitable, get in touch. Or book in for a free, no obligation, initial laser suitability assessment.