Refractive surgical procedures are treatment methods used to correct vision problems.
Laser surgery (usually using an excimer laser) on the cornea, such as LASIK, is widely used. In some cases, however, laser treatment is not an option, so refractive lens exchange may be a suitable alternative.
This is particularly the case for patients with severe refractive errors or who also have presbyopia. During refractive lens exchange, doctors remove the natural lens and implant an artificial lens.
Two types of artificial intraocular lenses @ Mohammed /AdobeStock
Since the 13th century, humans have been attempting to correct vision problems with visual aids. The first intraocular lens was developed in 1949 by Sir Harold Ridley (1906–2001).
During the war, Ridley observed that fragments of acrylic glass from aircraft cockpits did not trigger immune reactions in the eye following crashes.
Based on this discovery, Ridley developed the first artificial lens, which he initially implanted successfully in secret. In 2000, Queen Elizabeth II knighted him for his contributions to refractive surgery.
Since then, research has made significant progress in implanting artificial lenses into the eye. As a result, many people have regained better vision. The risk of complications with this procedure is very low.
Refractive lens exchange is recommended for severe nearsightedness or farsightedness. It is particularly suitable for people aged 45–50 and older, when the natural lens can no longer focus on close objects due to presbyopia.
Because a replacement lens is implanted, the natural refractive power (accommodative ability) of the eye’s natural lens is lost. For this reason, doctors perform refractive lens exchange only after presbyopia has set in.
The artificial lens is set for a specific distance. Typically, during lens replacement, doctors select a refractive power that enables sharp distance vision. For near vision—such as reading—a visual aid (glasses or contact lenses) is then necessary.
Individual preferences and habits, as well as the structure of the eye, determine which artificial lens is used. Standard artificial lenses for the eye (intraocular lenses) are usually available as monofocal lenses and adjust the eye’s refractive power. Doctors typically use them during cataract surgery to treat cataracts. Here, too, they correct nearsightedness or farsightedness.
Monofocal lenses do not correct astigmatism or presbyopia. Therefore, despite refractive lens exchange, visual aids are often necessary.
There are special intraocular lenses that offer additional features through further modifications. For example, multifocal lenses cover a range of focal lengths and enable sharp vision at both near and far distances. Toric intraocular lenses, on the other hand, correct astigmatism.
Since refractive lens exchange is often performed for cosmetic reasons, a thorough preoperative examination is particularly important.
This helps reduce risks and patient disappointment. Therefore, the physician should provide the patient with detailed information in advance and clarify whether the patient is aiming to be completely free of glasses.
Preliminary examinations prior to refractive lens exchange include:
- An ophthalmological examination, including dilation of the pupil
- Determination of visual acuity and the need for correction
- Measurement of intraocular pressure
- Measurement of pupil diameter (including in dim light)
- Assessment of corneal thickness, surface, and quality
- Measurement of axial length
- Examination of tear fluid and twilight and contrast vision
Refractive lens exchange is essentially the same as cataract surgery.
During the procedure, doctors remove the natural lens and implant an artificial lens. To do this, they make tiny, self-sealing incisions at the edge of the cornea (between 1.8 and 3.0 mm). They insert the surgical instruments and the artificial lens through these incisions.
When removing the natural lens, the surgeons open the lens capsule and aspirate the lens contents. They insert a foldable artificial lens into the clear capsular bag, where it is stabilized by small retaining clips. It does not need to be sutured in place.
Depending on the patient’s refractive error and expectations, doctors implant an intraocular lens with various optical properties. The exact selection and specification of the lens are determined in advance.
The following lenses are available for refractive lens exchange:
- Monofocal lenses (single-vision lenses):
These lenses correct farsightedness or nearsightedness. After refractive lens exchange, you will be able to see clearly at a specific distance (e.g., in the distance) without glasses.
Modern intraocular lenses are foldable and made of high-quality materials such as acrylates or silicone. They are very well tolerated.
A UV filter is standard today, and intraocular lenses with blue or violet light filters are also becoming increasingly common. They offer the retina additional protection against harmful influences and improve contrast sensitivity (e.g., while driving).
Better contrast can also be achieved with aspheric lenses, which is useful when the pupil is dilated or in twilight conditions. Since their shape does not change, accommodation (adjusting to see both far and near) is not possible. Therefore, you will need reading glasses.
- Toric intraocular lenses:
If you have astigmatism in addition to farsightedness or nearsightedness, toric lenses are recommended. To correct the astigmatism, the doctor marks the toric lens on the cornea before surgery.
The line-shaped markings on the edge of the lens are important for proper positioning within the eye.
- Multifocal lenses (multi-power lenses):
These lenses have multiple focal points, which ideally allow you to perform all daily activities without glasses afterward.
Various types of multifocal lenses are available depending on your needs. Therefore, you should discuss with your doctor in advance at what distances you would like to see without glasses. You should also inform your doctor about the activities you primarily engage in.
Since there are also optical drawbacks (increased halos around light sources), a detailed consultation is essential.
Accommodative lenses are suitable for correcting presbyopia.
Here’s how they work: force vectors cause the lens to move forward within the eye when looking at a nearby object.
Unfortunately, this mechanism has proven to be of limited effectiveness. However, compared to multifocal lenses, they have no side effects.
Accommodative lens with dual optics on the first day after surgery. With this lens model, only the front portion of the lens—which has a particularly high refractive power—moves forward, enabling a relatively good outcome.
Refractive lens exchange is typically performed on an outpatient basis under local anesthesia. The patient receives an injection next to the eye or anesthetic drops/gel.
The type of anesthesia used depends on individual factors. A complication-free procedure takes 10 to 15 minutes.
After refractive lens exchange, you will need to use eye drops regularly for several weeks. They contain a corticosteroid, often in combination with an antibiotic, to prevent inflammation.
The overall risk of complications is very low, although your doctor must inform you about possible complications, such as the risk of infection.
A common late complication is a posterior capsule opacification, which results from clouding of the capsular bag that holds the artificial lens.
For the patient, this means a gradual deterioration of vision that can occur months to years after refractive lens exchange. This phenomenon occurs more frequently the younger the patient is. Doctors can easily remove a posterior capsule opacification using laser surgery.
Depending on the type of lens, there are also specific optical side effects such as:
- Increased glare
- Double vision
- Reduced contrast
After refractive lens exchange, the patient must use eye drops regularly for several weeks. During the healing process, regular checkups with an ophthalmologist are scheduled to ensure that healing is progressing properly and without complications.
In addition, you should avoid swimming and saunas during this time to minimize the risk of infection. You should also avoid heavy physical labor. Furthermore, you should be careful not to rub your eye during the first few days.
In the long term, there are no restrictions on physical activity. However, you should limit your physical activity during the first few weeks after refractive lens exchange.
Refractive lens exchange is a form of modern refractive surgery and represents an effective solution for many patients with refractive errors. During refractive lens exchange, the eye’s natural lens is removed and replaced with an artificial lens that is individually tailored to the eye’s refractive power. Depending on the type of vision problem, various IOLs—such as monofocal or multifocal lenses—are used; these multifocal lenses allow for multiple focal points, thereby supporting sharp near vision.
Before any treatment, a specialist conducts a thorough preliminary examination to identify potential risks and select the appropriate lens. The procedure is performed through a tiny incision, during which the new lens is inserted into the capsular bag after the natural lens has been replaced with an artificial one. The exact procedure is standardized and is usually performed on an outpatient basis.
Refractive lens exchange is particularly beneficial for severe nearsightedness or farsightedness, as well as in older patients, when other procedures such as LASIK are no longer suitable. A similar principle is also applied in the treatment of cataracts. In this case, correcting the eye’s refractive power can lead to a significant improvement in visual quality.
Despite the many advantages, potential risks should always be taken into account, particularly those involving the lens capsule or complications following the procedure. Health insurance typically covers the costs only when there is a medical indication, not for purely refractive reasons. Nevertheless, refractive lens exchange has proven to be an effective method for becoming independent of glasses or contact lenses.
Overall, refractive lens exchange offers a long-term solution only after careful consideration, particularly in cases of severe refractive errors or when lens exchange is being considered as an alternative to visual aids.
What is refractive lens exchange?
Refractive lens exchange is a surgical procedure in which the eye’s natural lens is replaced with an artificial lens to correct a vision defect.
Who is a good candidate for refractive lens exchange?
Refractive lens exchange is particularly suitable for people with age-related farsightedness (presbyopia) or severe nearsightedness or farsightedness.
What types of lenses are used?
Intraocular lenses such as monofocal, multifocal, or toric lenses are used, depending on the individual’s vision problem and needs.
What are the risks associated with the procedure?
As with any surgery, there is a certain risk of complications, such as infections or problems with the lens; however, these are rare.
How long does recovery take?
The procedure is performed on an outpatient basis, and recovery is usually quick, so that many patients can see clearly again after just a short time.
