Who is suitable for laser eye surgery?
There are many misconceptions surrounding who is and who isn’t a suitable candidate for laser eye surgery. For example, many people assume that only nearsightedness (myopia) or farsightedness (hyperopia) can be treated, while others assume that they are simply too old for surgery, and others that they will automatically be accepted because they are young and healthy. The truth is that most people suffering with visual impairments are suitable for laser eye surgery, with around 80% of consultations being successful, but there are some conditions that mean laser eye surgery isn’t necessarily the best option. In these cases, it’s recommended that sufferers explore alternative methods, such as implantable contact lenses.
What Surgeries Are Available, And What Conditions Can Be Treated?
The most common types of laser eye surgery currently available are LASEK, LASIK and PRK, along with variations such as intraLASIK. Despite using slightly differing techniques, the end results are similar in that each method adjusts the shape of the cornea, correcting impairments. This means that all three commonplace procedures and their variants are generally suited to a host of eye conditions including myopia, hyperopia and astigmatism, although due to the differing techniques, some patients may prefer one surgery over another based on individual conditions.
PRK is widely considered to be the original laser eye surgery, and involves removing the outer layer of the cornea completely before replacing it. PRK is more suited to those suffering with shortsightedness than long sightedness, especially those with mild impairments, with research demonstrating a 93% success rate for mild complaints of up to -6 dioptres, dropping to just 30% for those with more severe impairments. In cases of advanced myopia, LASIK is generally considered to be a far more effective and safe procedure.
LASEK was born from the notions of PRK, but has since been superseded by the more advanced LASIK. LASEK involves making an incision in the outer layer of the cornea, rather than removing it, allowing for laser access. Both myopia and hyperopia can be treated with LASEK, with an estimated 96% success rate. Astigmatism can also be treated using this technique, although success rates are believed to be lower. As dry eyes are a relatively common complaint associated with LASEK surgery, it is recommended that patients who already suffer from dry eyes think carefully about whether this is the right procedure for them.
LASIK is the most recent and most advanced of the three primary forms of laser eye surgery. It involves creating a flap from the outer layer of the cornea, hinged on one side, that can be opened during the surgery, and then closed and allowed to heal. Reports suggest success rates of roughly 95%, making it one of the most effective treatments for many eye conditions. However, it’s not for everyone. Patients over 30 years of age are believed to be more at risk of complications, and those with either very thin or very thick corneas are generally unsuitable. In these cases, LASEK is usually the preferred option.
IntraLASIK is a relatively new addition to the laser eye surgery field, and uses blade-free technology to create the traditional LASIK corneal flap. Around 98% of surgeries are successful. However, some patients are considered to be unsuitable for this operation, particularly those with very thick corneas. It is believed that gas bubbles can form underneath the flap when the procedure is performed on patients with thick corneas, and this can limit the overall effectiveness of the surgery.
Wavefront-Guided LASIK is adapted for each individual patient, with 3D measurements of the eye taken prior to surgery to give patients the best chance of adequate vision. The techniques works well, with a reported 99% success rate. As the technology is very new, there are still some debates over who is and who isn’t suitable for this type of treatment. Whereas some sources claim those with large pupils are at greater risk of complications and should explore alternative laser methods, other sources refute this claim. A personal consultation is the best way to determine if a patient is suited to this treatment or not.
Who Isn’t Suitable For Laser Eye Surgery?
It’s estimated that around 20% of people who attend laser eye surgery consultations are not approved for the operation. There are a number of reasons why an individual may not be deemed suitable, but here are some of the most common reasons why patients may wish to look into alternative treatments, or wear glasses or contact lenses:
Pregnant Or Breastfeeding Women
Hormone changes have long been known to affect eyesight, but one French study, published in Contraception, Fertilite, Sexualite in 1985 specifically looked at sex hormones in relation to eyesight, and found that both the oral contraceptive pill and pregnancy affected vision. As vision is vulnerable to change during pregnancy, it is recommended that women wait until three months after birth to undergo surgery. In terms of breastfeeding, as medications may be needed to treat any complications, it is best to wait until the child has been weaned from the breast to prevent the possibility to passing chemicals through breast milk.
Those Under 18 Years Of Age
As the eyes are still developing during the teenage years, those under 18 years of age are deemed unsuitable for laser eye surgery as their vision could change dramatically. It is thought that eyesight is generally stabilised at 18, although some opticians argue that prescriptions tend to change frequently between 18 and 21, leading some clinics to only accept those over 21 years of age. Young patients should therefore discuss this with their consultant in order to determine whether they are suitable for the surgery, or would be best waiting a few years until their vision has completely stabilised.
Those With Presbyopia Only
Presbyopia is an age related condition that affects the muscles in and around the eye, causing a type of myopia. Reading glasses are usually recommended for treating presbyopia. Unfortunately, laser eye surgery cannot successfully treat presbyopia as the condition is not a fault with the cornea itself. If a patient has other conditions, such as myopia or hyperopia, they can be treated, although the presbyopia aspect will not see any improvement and reading glasses will still be required.
Those With Optic Nerve Damage
For glaucoma patients with optic nerve damage, laser eye surgery could exacerbate the condition as the optic nerve is vulnerable and likely to receive more damage. In this case, filtering microsurgery is a much better option for restoring eyesight. The surgery is very straightforward, it simply involves creating a small drainage hole in the eye to let the fluid buildup out, reducing the high pressure levels in the eye and bringing them down to a more manageable level.
Diabetics who manage their condition well and have no symptoms of the disease in their eyes are typically accepted for surgery, although this will depend upon a successful individual consultation. However, for those whose condition does affect the eyes, laser eye surgery may not be the best option. Not only does The Journal of Cornea and External Disease report a mere 47 percent success rates for LASIK surgery amongst diabetics, complications resulting from postoperative corneal infection are also believed to be much greater.
Those With Severe Visual Impairment
Laser eye surgery tends to work best in mild to moderate visual impairments, with success rates far lower and complications much greater in patients with more advanced conditions. For this reason, some clinics will not accept these patients due to the risks involved. However, there are alternative treatments for those with severe visual impairments, such as implantable contact lenses. Permanently embedded into the eye, these lenses can correct from -23 to +12 dioptres, and to +7 dioptres for astigmatism.