When Is Lens Replacement Not Suitable? Age, Retina, Glaucoma

Transparency note: This article is published by Mapa Health, a patient coordinator based in Istanbul and authorised by the Turkish Ministry of Health (licence AK-0456). It is for information, has a commercial background and does not replace advice from an ophthalmologist.

Quick answer: When is lens replacement not suitable? If you are younger than about 40 and still see well up close, with active diseases of the retina or macula, with uncontrolled glaucoma, with active inflammation in the eye and with certain diseases of the cornea. With high short-sightedness it is possible, but the risk of retinal detachment is higher. Additional limits apply to a trifocal lens. Whether the procedure suits you is shown only by a thorough preliminary examination, which Mapa Health arranges at the partner clinic in Istanbul.

At a glance

Age: usually sensible from about 50, generally not under 40 without presbyopia.

Against the procedure: active retinal or macular disease, uncontrolled glaucoma, active inflammation in the eye, severe corneal disease.

With caution: high short-sightedness, previous laser treatment of the cornea, very dry eyes, weak lens support structures.

Additionally against a trifocal lens: macular disease, advanced glaucoma, a lazy eye, very high demands on night vision.

Alternatives: laser eye surgery, ICL, varifocal glasses or contact lenses, waiting until a cataract develops.

Coordinator: Mapa Health, licence AK-0456, Trustpilot 4.5 out of 5 from 108 verified reviews, more than 500 patients supported since 2020.

Why the preliminary examination counts more than the offer

In lens replacement, the eye's own, still clear lens is removed and replaced with an artificial lens. Technically this is the same procedure as cataract surgery, one of the most common operations in medicine. Nevertheless it is a procedure inside the eye, and it cannot be reversed.

That is why the preliminary examination decides, not the offer. Among other things, the eye length, the cornea, the eye pressure, the cell layer on the back of the cornea and the retina with dilated pupils are measured. Be careful with providers who tell you before any measurement that lens replacement is possible for you.

Age and a still clear lens

Under about 40, the eye's own lens can still switch between distance and near. This ability is lost with lens replacement, and even a trifocal lens only imitates it. Anyone at this age without presbyopia therefore gives up something that works. Laser eye surgery or an implantable contact lens (ICL) is then usually the better choice.

From about 50 the picture changes. Near vision declines and the lens begins to cloud. Lens replacement then replaces something that is ageing anyway. Between 40 and 50, the measurements and your expectations decide. You will find a comparison in the article Over 40: Laser Eye Surgery or Lens Replacement? An Honest Comparison.

High short-sightedness and the risk of retinal detachment

With high short-sightedness the eye is longer than normal and the retina is thinner. After lens replacement, the risk of retinal detachment in these eyes is higher than in eyes with normal vision. This applies especially to younger patients.

This does not automatically rule out the procedure. It does, however, require a thorough examination of the retina beforehand. Thin or weakened areas are sometimes treated preventively with laser. After the procedure you should know the warning signs: suddenly many black spots, flashes of light or a shadow in your field of vision. Then you must see an eye doctor immediately. For younger, highly short-sighted patients with a clear lens, the ICL is often the gentler alternative.

Diseases of the retina and macula

With wet or advanced dry macular degeneration, diabetic retinal disease with swelling of the macula or a membrane on the macula, a purely refractive lens replacement is generally not performed. The retinal disease is treated first.

If a cataract is also present, the operation may still make sense. A monofocal lens is then usually used, because a multifocal lens would make the already weakened vision worse.

Glaucoma, inflammation and other eye diseases

With uncontrolled glaucoma, the eye pressure is treated first. With well-controlled glaucoma lens replacement is possible, but a trifocal lens is usually not recommended because it reduces contrast. One exception is a narrow drainage angle: here lens replacement can even be part of glaucoma treatment. The eye doctor decides this.

With active inflammation in the eye, such as uveitis, the eye should be free of inflammation for several months before the procedure.

With a lazy eye (amblyopia), a multifocal lens is generally not used.

With weak lens support structures, for example in pseudoexfoliation, the procedure is technically more demanding. It remains possible, but belongs in very experienced hands.

Cornea and dry eyes

With keratoconus or another very irregular cornea, the lens power is harder to calculate. Multifocal lenses are then usually not suitable.

With Fuchs endothelial dystrophy, the cell layer on the back of the cornea is weakened. Any procedure inside the eye can strain it further. That is why the number of these cells is measured before the procedure.

After previous laser treatment of the cornea, calculating the artificial lens is more difficult. This does not rule out lens replacement, but it requires particularly careful measurements.

Very dry eyes are treated first, because an unstable tear film distorts the measurement.

Expectations and night vision

Expectations are also part of suitability. If you expect a perfect image in every lighting situation or are very sensitive to glare, a trifocal lens will often not make you happy. Halos around headlights are common, especially in the first months. If you drive a lot at night for work, discuss this openly beforehand.

The partner clinic of Mapa Health uses the Alcon PanOptix trifocal lens, and the PanOptix Toric for astigmatism. If a monofocal or EDOF lens suits your eyes better, we tell you before you book. The differences are explained in the article Trifocal or EDOF? Which Lens Suits You for Lens Replacement.

The myth "Lens replacement is risk-free"

You often hear that lens replacement is completely safe, since it is just cataract surgery. What is true: the procedure is very well established, and serious complications are rare. It is not risk-free.

Rare risks include an infection inside the eye, swelling of the macula, raised eye pressure and the retinal detachment mentioned above. More common is posterior capsule opacification: after months or years, the capsule behind the artificial lens becomes cloudy. This can be corrected with a short laser procedure (YAG laser). A reputable provider tells you about these risks before you book.

When lens replacement does not suit you: the alternatives

Laser eye surgery: for a clear lens, a prescription that is not too high and a suitable cornea, usually up to about the mid-40s. When laser is not suitable is explained in the article When Is Laser Eye Surgery Not Suitable? Cornea, Prescription, Age.

ICL: an additional lens placed in front of your own lens, for high short-sightedness and thin corneas, without removing your own lens.

Varifocal glasses or contact lenses: no operation, no surgical risk, often the most sensible solution with a retinal disease.

Waiting: if a cataract is only just starting, it can make sense to wait until the operation becomes medically necessary.

How the assessment works at Mapa Health

Mapa Health is not an eye doctor but a coordinator authorised by the Turkish Ministry of Health (licence AK-0456). Send us your current glasses prescription, your age and any known eye conditions at info@mapahealth.com. This allows an initial assessment of whether lens replacement could be considered in principle.

The final decision is made at the preliminary examination in the partner clinic in Istanbul. If the findings speak against the procedure, it is not performed, and the eye doctor explains the reasons and the alternatives. You can check the reviews on Trustpilot yourself beforehand. Prices, process and package services can be found on our page about lens replacement in Turkey.

About the author

Tayfun Com is the founder of Mapa Health, the patient coordinator in Istanbul authorised by the Turkish Ministry of Health (licence AK-0456). Since 2020, the Mapa Health team has supported more than 500 international patients.

This article is for information only and does not replace a personal ophthalmological examination.