PreLex – Clear Lens Refractive Surgery
PreLex (Presbyopic Lens Exchange), also known as lens replacement surgery, clear lens extraction, or PreLex, is a refractive surgery for patients over 50 who wish to become glasses-free. While not widely known, it is often a more suitable option than LASIK for patients with presbyopia or high hyperopia. The procedure involves replacing the natural clear lens of the eye, responsible for focusing, with an artificial intraocular lens (IOL) called an implant. The implant corrects your vision and provides sharper focus, thus reducing your dependence on contact lenses, reading glasses, or progressive lenses. It is essentially a refractive cataract surgery performed before a cataract develops.
What is PreLex?
The procedure for exchanging refractive lenses is virtually identical to cataract surgery. The difference is that in the case of Prelex, the lens to be replaced is still clear; it has not yet become cloudy (as is the case with cataracts).
As with cataract surgery, vision is corrected with an artificial lens called an implant. Three types of implants are available to replace your natural lens, depending on your visual needs and eye health. These are:
Multifocal implants – These are the most commonly used lenses for PreLex; they offer multiple focal lengths for distance, intermediate, and near vision to provide clear vision at all distances.
Monofocal implants (conventional or toric) – Featuring one focal point. Monofocal lenses allow clear vision at distance, near, or intermediate distances, but not all three simultaneously. Toric implants used to correct astigmatism are also considered monofocal implants. Monovision is generally achieved: your dominant eye will be used for distance vision and your non-dominant eye for near vision.
Extended depth-of-field implants – These are improved monofocal implants that provide satisfactory distance and intermediate vision. While less effective than multifocal implants for near vision, they have the advantage of not causing halos around lights.
With intraocular implants, there is no "one size fits all", and your ophthalmologist will recommend the personalized choice that best suits your individual needs.
Who is affected?
Clear lens surgery for refractive purposes is generally intended for people with presbyopia, myopia, or hyperopia, for whom LASIK or PRK surgery is generally not suitable.
If you are 50 years of age or older, and suffer from both presbyopia and moderate to severe hyperopia or myopia, Prelex may be the best solution for clear vision and minimal dependence on glasses.
Please note, the operation will not make your eyes look 20 again, and the pre-operative assessment is an essential step to understand your needs and expectations.
Pre-operative assessment and eligibility
The pre-operative assessment is that of cataract surgery. Its main stages are as follows:
Interview, assessment of your visual needs and motivation.
Measurement of your visual acuity and refraction.
Ophthalmological examination using a slit lamp, fundus examination and OCT (high-resolution scanning).
Biometrics – Measurement of the morphological parameters of your eye: length, width, depth before the lens.
After the assessment, if you decide to have surgery, the receptionist will schedule an anesthesia appointment with you and two surgery dates (one per eye), approximately one week apart. You will be given a quote, including hospital fees, surgeon's and anesthesiologist's fees, and the additional cost of the multifocal implant. This implant is not covered by national health insurance because it is considered refractive surgery.
PreLex Procedure
Before the operation
The procedure is performed on an outpatient basis, meaning you will not spend the night at the clinic and will be discharged the same day. Here are the main things to keep in mind:
Remove your post-operative medications before the procedure so you don't have to rush to the pharmacy after surgery.
The day before the operation, remove your makeup carefully.
Remain fasting on the day of the procedure: do not eat, drink, or smoke for 6 hours before your arrival at the clinic.
On the morning of the operation, take a shower with mild soap (or with Betadine depending on the protocol established by the clinic).
Do not tie your hair up in a complicated hairstyle; you will need to be comfortable lying on your back on the day of the operation.
The operation
The lens replacement operation lasts approximately 10 to 15 minutes and is performed on an outpatient basis.
Each eye is operated on separately, usually one week apart. Here are the steps:
Anesthetic drops are instilled to numb the eye. If you experience anxiety, the anesthesiologist will inject a sedative.
The eye is disinfected with ophthalmic betadine, you will be covered with a sterile drape for perfect hygiene conditions.
A 2.2 mm incision is made around your eye.
The lens capsule is open in a circular fashion, this is called capsulorhexis.
Your natural lens is then separated from its outer shell (the capsule) using a cannula instilling sterile water (hydro-dissection).
The lens is then gently aspirated using a probe.
The chosen corrective implant is then inserted into the natural capsule. It is this capsule that will stabilize the implant.
An antibiotic is then injected to limit the risk of infection.
The incision is self-sealing; it does not require stitches.
You will then be taken to the recovery room to rest for a few minutes.
The return home takes place 1 to 2 hours after the operation.
Post-operative and recovery after phakic implants
Visual recovery is very rapid. You will notice an improvement in visual acuity without glasses the very next day. However, there is a period of neuro-adaptation to your new lens. Final visual results may take a few weeks to become established.
You may notice some vision problems such as blurred vision, halos and glare.
A sensation of "foreign body" or itchy eye is common in the first few days.
You can resume sedentary work on a computer and driving the day after the operation.
Gentle exercise can be resumed 3 to 5 days after the operation. Combat sports and swimming can be resumed 1 month later.
Vision after the operation
Most often, the final visual result is fully noticeable once both eyes have been operated on. Your vision will be clear the next day, satisfactory after a week, and stable after a month. You will see:
Clear at a distance, in intermediate vision and up close.
It is unlikely that you will need a pair of reading glasses. Your independence from glasses will be 90 to 100%.
Bright environments will be needed for reading because multifocal implants are energy-intensive.
Halos are frequently visible when driving at night.
Risks and complications
Just like cataract surgery, the most frequently performed surgical procedure in the world, PreLEx is a well-established surgery. However, there is no such thing as zero risk, and some potential hazards and surgical risks should be understood:
Refractive error – The implant calculation does not give exactly the expected result. Correction with glasses, laser, or implant replacement may be necessary.
Visual dissatisfaction – Light halos bother you in your daily activities in low light and dazzle you.
Capsular rupture – The natural capsule of your lens was too fragile and the implant could not be placed in it as planned.
Retinal detachment – Your retina, although previously examined, has a postoperative tear that could develop into a retinal detachment. This risk is particularly high in cases of PreLEx in highly myopic individuals.
Endophthalmitis – This is a serious, unpredictable eye infection that usually occurs between the 5th and 7th day after the procedure.
Frequently Asked Questions
Is it possible to feel the implant in my eye?
It is impossible to feel the implant in your eye, just as you cannot feel a well-placed dental filling for a cavity. Because the implant is located inside your eye and not on its surface like a contact lens, it is not visible to you or others.
How long does the implant last?
An artificial intraocular lens is a permanent and irreversible replacement for your natural lens. It is designed to last a lifetime, and its materials are very stable. Furthermore, the risk of regression (loss of corrective effect or deterioration of vision) over time is minimal or even nonexistent.
Can presbyopia be treated naturally?
Presbyopia affects almost everyone and usually becomes noticeable around age 40. It's a natural age-related condition in which the lens of your eye becomes firmer and less flexible. You lose the ability to focus on near objects.
How to correct presbyopia without surgery?
Non-surgical options for presbyopia include reading glasses or progressive lenses, and multifocal or monovision contact lenses. Isoptopilocarpine eye drops in the non-dominant eye, recently approved in the US for daily presbyopia correction, have not yet been approved by European authorities.
Why not have laser surgery?
PresbyLASIK, PRK, and SMILE all rely on monovision. The procedure therefore involves correcting one eye for distance vision and the other for near vision. This technique offers 80% independence from glasses, which is very good, but not as satisfactory as the 90 to 100% independence achieved by multifocal implants.
Furthermore, the PreLEx operation is permanent, whereas with laser surgery, you will probably develop a cataract between the ages of 55 and 65 and will need to be operated on again.