18.7.2024
Lesezeit:
6 minutes

Phake intraocolular lens

The abbreviation PIOL stands for phake intraocular lens and means that a type of contact lens is placed in front of the natural lens in the eye.

Dr. Valéry Vinzent Wittwer

operation process

The surface of the eye is made insensitive with anesthetic eye drops. An anesthetist can administer pain and sedatives through a vein on the arm as needed. When inserted, the PIOL is rolled up and slides through a small tube into the eye, where it slowly unfolds. With specially designed instruments, the soft lens is carefully guided at your corners into the space (sulcus ciliaris) between iris (arched skin) and natural lens. PIOL corrects the focal point in such a way that a sharp image of the environment on the retina is created.

1. Natural lens
2. cornea
3. Artificial phake IOL
4. Corrected focal point

In contrast to refractive laser eye surgery, PIOL implantation takes place inside the eye. This results in a low risk of intraocular infections and therefore requires a sterile operating room.

Scope of use of PIOLs

For corrections of minor to moderate vision defects, the laser eye procedure is preferred over a PIOL in normal corneas. The reason for this is primarily that laser eye surgery “only” treats the cornea while the PIOL is implanted inside the eye. Even though the risk of a serious complication is very low when implanting a PIOL, this is still lower with eye laser treatment.

PIOL is therefore primarily recommended for patients who have severe vision defects:

  • Myopia over - 6 dpt to a maximum of -18 dpt
  • Farsightedness above + 4 dpt
  • Astigmatism (corneal curvature) above 4 dpt up to a maximum of +6 dpt

PIOL is also being considered for patients who are not suitable for laser eye surgery due to thin or irregular corneas.

In the case of keratoconus, PIOLs should only be implanted when keratoconus progression has stopped and it is certain that the cornea is stable. Otherwise, cross-linking treatment should be considered beforehand.

Requirements for implanting PIOLs

  • Age >18 years
  • Defective vision stable for at least six months
  • Normal endothelial cell density on the back surface of the cornea (> 2000 cells/mm2)
  • sufficiently deep anterior chamber (>2.8 mm for nearsightedness and > 3.0 mm for farsightedness)

In patients with high farsightedness, the eyeball is smaller than in people with normal vision. Accordingly, the anterior chamber is usually too flat to safely implant a PIOL and no standard refractive operation can help the affected patient to achieve eyeglasses or contact lenses.

These requirements comply with Recommendations from the Refractive Surgery Commission — KRC as of June 2022

After the procedure

Since the procedure is performed on an outpatient basis, you should be picked up by an accompanying adult, as visual acuity is reduced after the operation. Your ability to react can also be reduced by narcotics, painkillers and sedatives.
Use prescribed medications regularly.

Medication schedule after implantation of PIOLs

Anti-inflammatory prophylaxis with Nevanac eye drops should be started five days before the procedure. Shortly after the procedure, you should take a tablet of Diamox to prophylactically reduce intraocular pressure and then use Tobradex eye drops every hour to prevent infections and inflammation. According to the plan above, the medication can then be slowly removed.

One day after surgery: control of eye pressure, vision, inflammation in the eye and location of the PIOL

One week after surgery: check whether vision has been achieved

One month after surgery: check the position of the PIOL in the eye and retina

After that, we recommend annual checks

FAQs - frequently asked questions

When should PIOL implantation be avoided?

As soon as one of the above requirements cannot be met.

Is the natural lens replaced during PIOL surgery?

No, the PIOL is positioned in front of the natural lens. 

Can you see right after PIOL implantation?

In the first few hours after surgery, vision is usually not yet completely clear and there may be glare. Even on the first day after surgery, vision is usually clear and sharp.  

What are PIOLs made of?

There are several PIOLs from different manufacturers, the most common being the ICL® from STAAR Surgical® and the IPCL® from CareGroup®. Both are made from biocompatible, i.e. materials that are easily compatible with humans. However, the exact components are still an industry secret.

Is the PIOL visible from outside?

No, the implant is neither visible to the operated patient nor to others. With the microscope, the position and position of the implant can be assessed.

Can you feel the PIOL after it has been implanted?

No, the implant is not noticeable. Since the PIOL is inserted in the back chamber of the eye, it cannot move.

Is PioLab being used or is it polluting my time?

The PIOL cannot be worn out, nor is the material attacked by the body's cells. Since the lens is implanted inside the eye, neither dirt nor bacteria can collect on it.

What are the risks of a PIOL implantation?

The main risks are infections and possible previous cataract (link) development. Today's IPCLs are mostly equipped with so-called aquaports, which improve the circulation of chamber water, which prevents premature cataract formation.

PIOL implantation vs. laser eye surgery

Benefits of PIOL
  • The operation is reversible, i.e. the lens can be removed again, after which the eye can be returned to the same condition as before the operation.
  • The eyes do not get drier after surgery
  • The biomechanics or stability of the cornea are not affected
  • Significantly larger visual defects can be corrected
Disadvantages of PIOL
  • Since this is an intraocular procedure, there are greater risks (e.g. infection) than laser eye surgery, which “only” treats the cornea.
  • The implant is tailored to the patient and must be manufactured accordingly. As a result, there are longer waiting times of one to three months
  • The costs are significantly higher than laser eye surgery, as the operation takes place in operating room I accompanied by an anesthetist
Why are post-implantation checks important for PIOLs?

PIOLs can lead to clouding of the front natural lens, which can first cause glare and later also a decrease in vision. The newer generation of PIOLs therefore has small pores (aquaports) through which the anterior chamber water flows and thus a nutrient exchange can take place.
The risk of clouding the natural lens is lowest when the distance from the implant to the natural lens is sufficiently large.

  • This distance can be measured using OCT (optical coherence microscopy)

The inserted implant can rarely reduce the outflow of anterior chamber water and may result in an increase in eye pressure and thus damage the optic nerve.

  • In follow-up checks, optic nerves and eye pressure are therefore examined and compared with the values before surgery

Very rarely, implanted PIOL has a negative effect on the endothelial cells at the back of the cornea.

  • During the follow-up, endothelial cell density is analyzed and compared using mirror microscopy
Are treatment costs covered by health insurance?

Basic insurance is generally not allowed to cover the costs of laser eye surgery or the implantation of PIOLs.

If the patient cannot tolerate contact lenses and the difference in defective vision between one eye and the other eye is more than three diopters (anisometropia), health insurance must cover the cost of one eye.
Supplementary insurance often covers part of the costs of refractive procedures. In case of doubt, we recommend that you check this with your health insurance company in advance.