In last month’s article we looked at the different types of refractive surgery. This time we look at the advantages and disadvantages of each type, including potential complications.
SMILE (small incision lenticule extraction)
A significant benefit of SMILE is that it only needs a very small corneal incision, and a small lenticule (disc) of tissue is removed. There is no corneal flap created as with LASIK, which means the cornea is minimally disturbed. This reduces potential complications, including dry eye, probably because fewer corneal nerves are involved in the process. It can correct myopia, a small amount of astigmatism but not hypermetropia. Higher amounts of myopia can be corrected than with LASIK.
Disadvantages of SMILE include glare and haloes around lights, which can be especially disturbing when driving at night. It is also possible that some debris may remain after the lenticule has been removed. The procedure can only be done once, so if any additional treatment is needed, this needs to be done with surface PRK. Inflammation and infection are risks associated with any type of surgery.
LASIK (laser assisted in situ keratomileusis)
Myopia, hypermetropia and astigmatism can be corrected with LASIK. The procedure is quick (10 minutes per eye), and most people see an improvement in their vision within a few hours.
Complications include over or under correction and possible regression, with about 10 per cent of patients experiencing some regression after 10 years. Glare, starbursts and haloes around lights can also sometimes be experienced.
Infection and inflammation are also potential complications, and sometimes
there can be problems with the corneal flap post-surgery, and so additional treatment may be needed. Dry eye can also be experienced post-surgery.
PRK (photorefractive keratectomy)
As there is no flap to dislodge, this means PRK may be a better option for patients who lead a very active lifestyle, as being hit in the eye can move the flap out of place, even after it’s healed. It is also better for thinner corneas and dry eye syndrome. It is possible to correct myopia, hypermetropia and astigmatism.
The main drawback to the patient is the procedure is more painful than the other procedures, and the recovery time is longer. Glare and haloes around lights is also a complication, as is corneal infection and inflammation. Corneal haze, which is a clouding of the cornea is also a small risk, and there is the possibility that the vision may be over or under corrected.
LASEK (laser epithelial keratomileusis)
There is less chance of dry eye syndrome with LASEK as the flap is not as deep as LASIK. It also avoids the flap associated problems with LASIK, although the recovery time is longer, and can be more uncomfortable. There is a small risk of corneal haze developing. Over or under correction are also possible, as is regression. LASEK is an alternative to LASIK but is usually only performed if the patient is not a good candidate for LASIK, due to the slower visual recovery time and the increased discomfort.
Although these complications may seem daunting, it must be remembered that they are rare, and that for most patients the benefits of being able to be less dependant on spectacles outweighs the disadvantages.
Sue Deal FBDO R is a practising dispensing optician, ABDO College examiner, senior tutor and supervisor for dispensing opticians. She is also a practice visitor and external moderator for ABDO. She was recently awarded the ABDO Medal of Excellence for her outstanding services to the profession.