Laser Eye Surgery, Vision Correction Surgery and Multifocal Lens Surgery Explained.
If you have decided that you no longer want to rely on spectacles or contact lenses to see clearly, you have probably started researching the alternatives. The internet will reveal a potentially bewildering array of options; LASIK, LASEK, PRK, refractive lens exchange, implantable contact lenses, KAMRA, Clarivu, corneal inlays, toric lenses, multifocal lenses, trifocal lenses, Raindrop, Femto eye surgery, accommodative lens implants and so on. With this in mind we have provided a simple guide to help you choose the right treatment for your circumstances.
Step One: Laser Eye Surgery or Refractive Lens Exchange- which one is right for me?
The vast majority of vision correction procedures involve either a laser procedure to change the focusing power of your cornea (laser eye surgery to the front surface of your eye) or removal of the natural lens behind your pupil, and replacement with a premium lens implant such as a multifocal (refractive lens exchange). The best option for you will actually depend on several factors, but the most important factor is probably your age.
Age and vision correction
Vision correction surgery is carried out on people aged approximately between 20 and 70 years. This group can be split in half to form a young group aged 20-45 years, and an older group aged 45-70 years. In the young group it is normal to still have a good range of accommodation, which means the eyes are able to focus from distance through to near through a subconscious muscle mechanism which surrounds the lens inside the eye. Young people are generally more suited to a laser eye surgery procedure to reshape the cornea, which does not interfere with the muscles of accommodation. People who are older tend to have compromised accommodation, so they struggle to focus from distance to near without the help of reading spectacles. They are also more likely to have early cataract formation, and for these two reasons it may be more appropriate to consider refractive lens exchange. This is only a rough guide though and there are many other factors to take into account and you should spend time with your chosen surgeon discussing the pros and cons of each before making a decision to proceed.
Step Two: I'm a younger patient. Which Laser Eye Surgery procedure?
Laser eye surgery techniques include LASIK, LASEK, PRK, 'no touch LASEK', SMILE, standard laser and customised laser. The most common procedure performed globally is LASIK and this is also the best known. All these procedures are variations on the same theme which involves changing the surface contour of your eye by a very small and very precise amount to allow for a sharply focused image on the retina. All laser eye surgery procedures in this context require removal of some tissue, and part of your assessment involves making sure enough tissue is left behind for the treatment to be safe. LASEK and PRK laser is applied to the surface, while LASIK and SMILE are laser procedures in the deeper corneal tissue, carried out under a flap, which must be created with the use of either a special knife (microkeratome) or a special kind of laser (femtosecond). Customised laser requires removal of larger amounts of tissue than standard laser, but in certain circumstances it can give better visual results.
The best type of laser for you really does depend on a number of factors (e.g. your spectacle prescription, whether or not you have dry eyes, how thick your cornea is, your lifestyle etc) but in very general terms, the surface laser without flap creation can be safer, and preferable whenever appropriate.
Step Three: I'm in my fifties. Which type of Refractive Lens Exchange would you recommend?
In 1949 the world's first ever artificial lens implant (monofocal) procedure was carried out in London. For the next 60 years monofocal lens implants became established as standard practice during cataract surgery and are still the most widely used lens implant (in the NHS) to this day. Monofocal implants aim to correct distance vision, but not astigmatism or near vision, so the recipient of these lenses should expect to need glasses after surgery for some or all of their daily activities. From 1999 premium lenses have been available (not in the NHS) as an alternative to standard monofocal lens implants for use during cataract surgery and/or refractive lens exchange. Premium lenses include toric, multifocal, multifocal toric, trifocal and accommodative lenses, and the purpose of these implants is to correct astigmatism, near and distance vision all in one lens, so the recipient does not need spectacles or contact lenses to see well. If you are over 45 years of age, or have a degree of cataract, or are very long sighted, premium lens refractive surgery is probably a better option for you than laser eye surgery.
Step Four: I've had great vision all my life, I'm just starting to struggle with my reading vision.
If this applies to you then you probably need a solution for presbyopia. You may choose premium lens exchange under these circumstances, or alternatively a dedicated presbyopic solution such as a corneal implant in your non-dominant eye. Examples include the KAMRA inlay and the Raindrop. These devices are used to create a central island of near visioning the non-dominant eye to give more effortless reading vision. Cornel inlay technologies are relatively new, and their success rates, complications and tolerability have not yet been fully established.
Step 5: Are there any reversible procedures?
Sometimes a patient may not be ideally suited to laser or lens exchange. An alternative option for a minority or people is an implantable contact lens (ICL). These lenses can be especially good in young short sighted patients, but do require long term follow up once yearly to make sure the implant is well positioned.