The abbreviation PRK stands for “photorefractive keratectomy” and describes the principle of surface treatment, as it was first performed in 1987. Since then, the treatment has been continuously developed and improved.
The ocular surface is made insensitive with anesthetic eye drops. A so-called excimer laser then removes tissue from the cornea and thus changes the refractive power of the eye. The cornea is modelled exactly in such a way that visual defects such as short-sightedness or astigmatism are compensated for.
With conventional PRK, the top layer of the cornea is removed with a knife. With the more modern TransPRK, this is also done with a laser, so that there is no longer a need to use a blade. Depending on the manufacturer of the laser device, the same process is called CTen, Trans-PRK, SmartSurface or touch-free PRK.
The procedure itself is painless, but tears, foreign body sensation and often burning pain occur in the first two days after the procedure, which is why painkillers are given. After three days, the top layer of the cornea (epithelium) is overgrown again and the symptoms significantly decrease. As a result of the fact that the epithelium grows from outside to inside, as in a healing wound, a so-called end strip is created in the center of the cornea, which reduces visual acuity to approximately 10-20%. After one week, vision improves to around 80%, after about two weeks, vision is clear. Visual acuity can fluctuate slightly at a high level for up to two months, after which the healing process is completely complete and definitive vision is achieved.
Medication after surgery
No, the procedure is completely painless. However, there is often a foreign body sensation, burning and tearing during the first two days. To make this time more pleasant, we prescribe painkillers.
In contrast to Femto-LASIK, vision is significantly reduced after PRK. After approximately one week, vision of 80% is measured, which continues to improve over the following weeks.
Yes, if you can accept reduced visual acuity for two weeks. If you wish, you can also treat one eye at a time at intervals of 2 to 4 weeks. However, most patients want treatment on both eyes at the same time.
Contact lenses leave a temporary imprint on the corneal surface, which can influence the result of PRK/trans-PRK. You should therefore stop wearing contact lenses up to one week before the procedure (2 weeks for hard contact lenses).
After one to two weeks, you can return to work.
As a rule, no certificate of incapacity for work can be issued. Absence from work should therefore be counted as vacation, reduction of overtime or the like.
In over 95% of treatments, there is no longer any residual defective vision after surgery. The remaining 4% have a slight residual error that is not annoying. Only in very rare cases is further surgery necessary. This is usually the case with major corneal curvatures and can therefore be identified and discussed in advance.
Yes, as long as the cornea does not become too thin, as corneal tissue is removed during every laser procedure.
If the eyeglass values are stable for several months before the procedure, the length of the eye no longer changes, and the laser correction will stop for the distance accordingly.
From around the age of 50, the presbyopia Enter and vision in the vicinity slowly deteriorates.
From around 60 years of age, it can become a The natural lens becomes cloudy, in which the light is refracted differently and a new visual defect becomes noticeable as a result. In these cases, a Cataract surgery Improve vision again.
In principle, the earlier the eyes are operated on, the longer you can benefit from the absence of glasses or contact lenses. However, the prerequisite is that the visual defect does not increase further before the operation, which is often not the case until the end of twenties.
Between 40 and 50 years of age, the presbyopia Or presbyopia, which cannot be prevented even by PRK surgery. Reading glasses must then either be worn or one eye is corrected for proximity (monovision/multifocal ablation profile).
From the age of 35, we recommend making the non-executive eye slightly short-sighted (-0.5 to -0.75 dpt). The non-guide eye therefore sees a bit less sharply in the distance than the guide eye. The advantage is that later, when presbyopia occurs, you can see more closely with your undercorrected eye. This condition of slightly unevenly corrected eyes is called mini monovision and aims to delay the need for reading glasses.
If necessary, this mini monovision could be reinforced later with another procedure to extend the freedom from glasses.
During the preliminary examination, we check whether this mini-monovision is tolerated by the patient. If the undercorrected eye is disruptive to the visual impression, we still recommend that you completely correct the visual defect in both eyes.
Especially in patients with large pupils, bright light sources in the dark will be perceived differently after PRK than before. For example, round halos or star effects (star bursts) can occur in the area of light sources. As a rule, these phenomena cause little or only disturbance during the first few months after the procedure, as the brain gets used to them quickly.
Especially in people who have had dry eyes before the procedure, the feeling of dryness may intensify in the first few months after PRK/Transprk.
Since PRK has been carried out since 1987, long-term risks can also be well estimated.
The most common risks include:
Seletene risks
Most PRK complications occur shortly after surgery, so monitoring on the third day after surgery is particularly important. Inflammatory reactions, which can lead to scar formation, occur very rarely.
PRK reps. TransPRK removes corneal tissue, i.e. the biomechanics and thus the stability of the cornea can change as a result of the treatment. Any weakening of the cornea (keratectasia) can be identified and treated at an early stage through annual checks, but this is rather unlikely with PRK compared to LASIK.
