Common Eye Conditions
Refractive (Laser) Surgery
What types of surgery are available?
What is laser surgery not good for?
Refractive Surgery trivia
Although laser surgery is by far the most common form of surgery used it is not the only option and although hopefully this information explains a little about the benefits and risks it is best to discuss the matter with a knowledgeable source to get the ‘full picture’, in particular what may be beneficial in your case.
The power of the eye is governed to a great extent by the curve on the front of the eye (the cornea). Most forms of refractive surgery aim to change the corneal curve so that it matches the length of the eye and gives a clearer unaided image or lessen the power of lens needed to correct the focussing system. The intention is to create perfection but a realistic goal is to achieve a marked improvement, often but not always perfection itself. This is not a slight on the surgeons who carry out this surgery or their tools or patient management but an acceptance that mother nature does not always heal and respond exactly the same in different people and so even perfect surgery in different eyes can sometimes create slightly different end points.
The buzzword that many refractive clinics use is ‘functional’ vision.
What does this mean and is that an acceptable end point? One of the best descriptions I heard of this is that imagine you went for surgery because you wanted to play football. You couldn’t play in your glasses for obvious reasons, you can’t see well enough without them to know who’s who and contact lenses are not an option. It would be a very realistic expectation that after surgery you would be fine to play football but if you went to watch Manchester United from the back of the stands or wanted to see how many minutes were left to play in the corner of the TV screen watching Match of the Day you may want to put on some low powered spectacles to tidy things up. You could function quite well generally but things may want sharpening occasionally. top
Patient Satisfaction,
I have referred quite a few patients for surgery and without exception the patients who have gone on to have surgery have told me that they are very happy with the outcome. A fairly large percentage (approximately 35%) have been told that they are not suitable due to conditions in the eye and some I have referred have decided that this is not the option for them at the moment having had further talks with the surgeon. I have recently decided that I do not wish to advise on the merits of one surgeon or company over another as I find I have to keep visiting and reviewing each ‘outlet’ on a regular basis to check that my recollections of a particular supplier have not changed due to staff movements or practice buy outs etc. I feel that it is best that you ask for a copy of past results from the surgeon who will be doing your operation, this may well be different from the results of the clinic as a whole. It is worth checking how many of your type of operation that surgeon has performed, although everyone has to learn and there is good supervision of new surgeons I would personally prefer an ‘old hand’ to be responsible for me if I was undergoing the operation.
What types of surgery are available?
Cataract surgery has been a form of refractive surgery that has been practiced for very many years and amongst the more senior members of society (late fifties onwards) this should certainly be thought of as an option, even if there is not a cataract present!
Radial Keratotomy is a form of surgery that is not as popular
as it once was (some may remember a cruise ship anchored off Cyprus in the 1980’s where an extremely skilled Russian surgeon performed operations) and involves making incisions into the cornea in a radial pattern. The depth and size of these incisions were intended to weaken the corneal structure sufficiently to cause the cornea to ‘collapse’ to a flatter curve. This from of surgery is still in use but on a limited scale.
Intra Stromal Rings are thin semi-circular rings
that are slid into the middle of the cornea and cause the cornea to reshape itself to the required curvature. There are limited clinics where this form of surgery takes place. It has the advantage that the rings can be removed at a later date if they are not successful, no other form or refractive surgery is reversible to my knowledge.
Anterior Chamber Implants are like having a small contact lens placed inside the eye, and sitting in the front chamber of the eye, a little like they used to use following cataract surgery in the years gone by.
This falls into two camps.
Photo Refractive Keratectomy
or PRK for short is the form that has been used for longest. This method is now only used when lower power changes are wanted and involves removing the front cells (epithelium) from the whole of the cornea, working with the laser on what is now the front of the eye. Following this the epithelium needs to regrow over the cornea before reasonable vision is achieved and it is not uncommon for the refraction to take six months to settle fully. For this reason this form of surgery is normally done one eye at a time with a period of some weeks or months between. I have talked to patients who have had this form of surgery (not at Maxivision) and have had mixed responses regarding their experiences, particularly concerning comfort following the operation. Some have talked of it being uncomfortable afterwards but there are some who talk of considerable discomfort or pain for some days.
Due to the prolonged healing phase and the possibility of marked discomfort I do not feel comfortable recommending this form of surgery, I would not want a member of my family to undergo it.
LASIK (Laser in Situ Keratomileusis) is the newer form of surgery
and it is because of its results that I felt that I wanted to become involved with this aspect of optics. In this form of surgery a small flap is created in the cornea, it is folded over and the laser works on a deeper area of the cornea, the flap is then folded back and reseals itself without stitches. Because only a small thin wound (the incision made to create the flap) is made it heals much more quickly. As the nerves at the front of the eye have had a protective flap replaced covering them there is much less discomfort.
The end result is that a good vision is normally achieved within 24 / 48 hours
with approximately 95% of the best result within one week. There seems to be some slight further healing over the next couple of months giving a stable vision within three months. Most of the patients I have talked to regarding the operation describe the discomfort as being minimal, a little like a bad contact lens day, annoying but not painful for the first 24 hours. Most people mention disliking bright lights just after the operation and some find that they find artificial tears helpful occasionally over the first couple of months as the eye can feel a little dry.
Both eyes are normally operated at the same session
and typically you would be in the operating theatre for about twenty minutes. The actual laser is functioning for approximately 40 seconds. Although I personally would not want to undergo surgery (I don’t need spectacles so probably don’t appreciate the frustration) as I am the sort who cannot accept an unnecessary risk but I would feel happy if my wife wanted surgery (I am happily married, not divorced if you were wondering). I would be concerned on the day of the surgery, who wouldn’t be, but would expect a good result.
What is laser surgery not good for?
When the eyes reach the age of mid forties they lose the ability to change their power to enable them to read. This is a problem where the eye cannot change from its base power and all forms of refractive surgery will not help this as the surgery will only change your base power. Some surgery centres suggest correcting one eye so that it sees in the distance and the other corrected for close work. This is a form of correction that is used quite often with contact lenses and I find quite a reasonable success rate there but it is a way of correcting that some people find very unacceptable. With contact lenses there is an easy remedy if this form of correction doesn’t work, you revert to two fully corrected eyes , but this option would not be available following surgery. For this reason a prolonged trial of this form of correction with contact lenses pre operatively is necessary. If your only problem is reading unfortunately I would say that surgery is unlikely to help.
There are limits to the amount of power change that can be achieved
with a laser as there must still be enough cornea left post operatively to have a stable, strong eye. The amount of long sightedness that can be corrected is normally approximately 4 dioptres whilst short sightedness can normally be reached up to a limit of roughly 10 dioptres. These figures are very dependant on the natural thickness of your cornea and so all cases are considered on their own merits.