In this article, you will learn what side effects I witnessed after fitting 100 customers with Ortho K lenses. In most cases when you hear about the experiences you get just a very narrow look at this very interesting topic. This is why I wrote the post to give you more in-depth information on what to expect from orthokeratology.
My experiences in fitting Ortho K lenses range from lower hyperopes with lower prescriptions (less than +3.0D) up to higher prescriptions for myopes (up to -9.50D). Ortho K lenses in general can be bought as single vision or multifocal variants. I fitted all of them. All of the Ortho K lenses available lead to a temporary reduction of the actual myopia, hyperopia, astigmatism, or presbyopia. This means ortho-k lenses are meant to be worn every night.
Generally speaking most experiences from customers is very positive. But those lenses do have some drawbacks. I will list them below:
- Fluctuations in visual acuity
- Corneal staining
- More checkups needed
- Halo effects
The advantages of Ortho K lenses:
- No foreign body sensation during the day
- Oftentimes works great even with dry eyes
- Myopia control effect
In this article I will try to stay as objective as I can when I write about my experiences here. I want to make clear every Ortho K fit needs to be looked at individually. When the prescriptions is -3.00 and the shape of the cornea is perfect I can expect the wearer to have a great time with the lenses and really little drawbacks.
However, when the prescription is -7.50 the wearer might take on more compromises. Why will be explained in the lower part of this article. First of all, let us talk about the fluctuations in visual acuity.
Sometimes People Experience Clear Vision and on Other Days the Ortho K Lenses Might Not Work as Expected
Most people in general do not have a high prescription. Those people with myopia of fewer than -4.50 Diopters experience a really stable vision and only very seldom fluctuations in their visual acuity. Where do these fluctuations come from? You need to apply a few drops of saline before putting the lenses on your cornea.
Sometimes the wearer produces a little bubble that forms in the periphery of the lens. When this happens the Ortho K lens will not work properly. In such a case you might wake up with the lenses put them out and discover “huh, one eye is not as sharp as usual”
So the placement of the lenses and how good you can handle the lenses will have a lot to do with how good your experiences with Ortho K lenses will be. When you push your pillow a little into your eye while sleeping the lens could be repositioned a little. This could also lead to a slight drop in visual acuity which you would discover the next morning. But as I said the experience I made with my customers below -4.5 diopters is just fine.
But things change when the prescription gets a lot higher. Depending on how sensitive your eyes are to the changes an ortho k lens produces a fitting with 7.50 diopters has way less room for repositioning of the lens at night and has now drawbacks tomorrow morning.
The reason, therefore, is the smaller zone on your eye you can use to see properly. When the prescription is lower the zone is bigger and when the lens moves a little at night there will not be an issue but with a smaller zone, you could use to see good a smaller reposition probably will end up in a noticeable drop in visual acuity next day.
Now you might ask what drop in visual acuity did I actually experience when vision fluctuated? And the range was quite big. I had customers during a checkup and measure they suddenly needed -1.50 diopters although on a good day they were at 20/20 vision with 0.00 diopters left.
When this happened a lot I would recommend switching back to normal lenses. Because visual acuity just needs to be stable during the day.
What Side Effects Did I Observe in Fitting 100 Ortho K Customers?
In some cases when people come in during the first checkups you can see mechanical stress on the cornea. Just a side note here those effects are not only present with Ortho K lenses you can also experience them with normal lenses. In general, the eyes of ortho K customers look better than with people fitted with normal soft contacts. But during the first check-ups images like the one below can be observed.
This picture in the upper half shows corneal staining which means the part of the eye is basically stressed, some cells are either damaged or dead (this heals during the day) but of course, such an issue needs to be fixed. So when this happens usually the contact lens needs to be reordered in a changed shape which will not produce the bearing which damaged the cells on the eye. In this case the customer made a handling mistake in the night before. After takling this trhough this the fitting of the ortho K lens worked just like charm.
And of course the exprience of the customer coming in getting the lens evaluated by the optician and then sleeping with the lenses and coming back especially during the first weeks usually four times can be a little time consuming. Usually it takes about 3 weeks until most people reach best visual acuity. During this time daly contacts need to be used until you do not need contacts to see perfectly.
Three weeks is very manageable for most people. But when the prescription is extremely high it is often pretty hard to know if the customer will even get to the point of 0 diopters. In some cases, the eyes will not work well with the lenses. But this is rather seldom the case and usually just with prescriptions over 5 diopters. Because at this stage the halo effects will be a lot more dominant.
The contact lens reshapes your eyes and the prescription you had with your glasses is still found on your eye. When you measure the shape of the cornea you will see the part over your pupil got optimized for best visual acuity but the old prescription which for example made you myopic is reshaped into the periphery of your cornea. Which means you have a ring of your old prescription around your pupil.
Druing daytime this is not an issue because the bright light keeps your pupils smaller. But at night or even in a room where it is not so bright your pupils will get wider and what you can experience with Orhto K lenses is a slight loss in visual acuity. Depending on how high your prescription was before you will notice this effect more or less. Some people notice halos when looking at street lights at night.
For most people this experience is not a dealbreaker. But when you need to drove a lot at night it might be problematic.
What Is Actually Good About Ortho K Lenses?
With Ortho K lenses you will not experience dry eyes as with other contact lenses. Because in comparison to normal contacts Ortho K lenses do not sponge your tear film. In addition to that, there will be no foreign body sensation because you do not have lenses on your eye during the daytime. Also, I spoke about the fluctuations in vision with Ortho ks before. But normal contact of course could also produce fluctuation when the wetting is not optimal for example.
One of the biggest advantages of using ortho k lenses is the myopia control effect for children. This means when myopia is progressing with ortho k studies have shown the progression slows down. Over the years the wearer of the ortho k lenses will then end up with a lower prescription. I think these benefits can not be stressed enough.
In this article the more words are written about the side effects and the drawbacks about ortho k lenses that could be experienced. However for most people the benefits will outweigh the disadvantages when the first phase of the fitting is over after a few weeks and the day starts with clear vision and no need for contact lenses or glasses during the day.
I wish you a great day.