Eye surgery: techniques, indications and precautions

Which eye surgery matches your vision problem?

Difficulty seeing clearly can come from several structures. The cornea, transparent at the front of the eye, and the lens, sitting behind the iris, both help to focus images. The retina receives light and passes the information to the brain through the optic nerve. An operation can act on one of these structures without repairing the others. That distinction explains why an effective treatment for short-sightedness does not cure a retinal disease.

Refractive surgery mainly seeks to reduce your dependence on glasses or contact lenses. Cataract surgery treats the clouding of the lens, with the option of correcting certain optical defects at the same time. Glaucoma and retinal operations often aim to preserve vision that is under threat. How urgent they are, and what counts as success, therefore differ from an operation chosen for everyday comfort.

Any recent drop in vision should be examined before you start looking for a technique. Glasses that have become inadequate may reveal a change in correction, but also a cataract or a condition that needs another treatment. A sudden loss of vision, a dark shadow over your vision or significant eye pain warrant urgent assessment, without waiting for a planned surgical consultation.

Correcting refractive errors with refractive surgery

Short-sightedness, long-sightedness, astigmatism and presbyopia

In short-sightedness, distant objects look blurred. Long-sightedness can increase the focusing effort and disturb near vision as well as distance vision, depending on its degree and on your age. Astigmatism produces different focusing along the different axes of the eye. Surgical correction seeks to change the optical power so that focusing falls closer to the retina.

Presbyopia is the gradual decline of accommodation, in other words the ability of the lens to adjust focus. Correcting your short-sightedness does not remove this ageing process. Someone operated on young may therefore need reading glasses later. Conversely, a short-sighted person with presbyopia who used to read by taking off their glasses can lose that convenience if both eyes are corrected for distance.

Your objective should set out your priority uses: driving, reading, screen work, sport or precision work. There is sometimes a compromise between several distances. Monovision, for instance, favours distance vision in one eye and closer vision in the other. A trial with contact lenses can help you judge how well you tolerate it before a surgical decision.

LASIK and femto-LASIK

LASIK combines the creation of a corneal flap with reshaping of the underlying tissue by excimer laser. The flap is then put back in place. When it is prepared with a femtosecond laser, the procedure is called femto-LASIK. IntraLase is the name of a technology used for this step: it is not an operation competing with LASIK.

Functional recovery is often quick, but it is not the same as immediate stabilisation. Dryness, fluctuating sharpness or halos can disturb the first few weeks and sometimes persist. The presence of a flap also counts in the choice for a patient exposed to eye trauma. The assessment looks at the shape and thickness of the cornea, together with the volume of tissue that would remain after correction.

The guide devoted to LASIK with IntraLase sets out this technique and what follows it. The name of a machine alone, however, cannot establish whether your eye can be operated on, or what visual quality you will obtain.

PRK and lenticule extraction

PRK acts on the surface of the cornea once its epithelium has been removed. It creates no flap. The surface then has to rebuild itself, which explains the pain or initial discomfort and a recovery that is generally more gradual. It can be considered when certain features make LASIK less suitable, but a suspect cornea does not automatically become operable by PRK.

Lenticule extraction, known in particular under the name SMILE, involves shaping a thin disc of tissue inside the cornea with a femtosecond laser, then removing it through a small incision. What it can achieve depends on the device and on the correction to be treated. Surface techniques, LASIK and lenticule extraction are therefore not interchangeable for every refractive error. The Hospices civils de Lyon and the Geneva University Hospitals describe these families of procedures.

Intraocular lenses: keeping or replacing the natural lens

The phakic lens keeps the natural lens in place

A phakic lens is placed inside the eye while the natural lens is left in place. It can be an option for certain large corrections, or when corneal laser surgery is not chosen. The surgeon assesses the space available inside the eye, the state of the cornea and the other ocular structures. High short-sightedness on its own is not enough to confirm this indication.

This procedure avoids reshaping the cornea, but it introduces an intraocular device that calls for monitoring. Depending on the lens and on your anatomy, follow-up looks for a change in pressure, damage to the corneal cells or clouding of the natural lens. Keeping the natural lens preserves what remains of its accommodation, without preventing future presbyopia or an age-related cataract.

Replacing the lens answers a different logic

The lens may be removed because it has turned opaque, in the setting of a cataract. It may also be replaced for refractive purposes in certain carefully selected situations. In this second case, the expected benefit has to justify intraocular surgery on a lens that is sometimes still clear. Age, remaining accommodation and retinal risk all weigh in that discussion.

Once the lens has been removed, a monofocal implant usually favours one distance. Extended depth of focus implants and multifocal implants seek to widen the range of distances usable without glasses, with different optical trade-offs. A toric implant corrects astigmatism; it can belong to several of these categories. The word ‘toric’ therefore does not mean ‘multifocal’.

Multifocal implants can reduce the need for glasses, but they can cause more halos or glare in some patients. The condition of the macula, the cornea and the optic nerve has to be compatible with this choice. Freedom from glasses remains an objective, not a guarantee of sharp vision in every situation.

Cataract surgery

A cataract is a clouding of the lens that can blur vision, dull colours and increase glare. Changing your glasses sometimes improves comfort for a while, but it does not make the lens clear again. The operation removes that lens and replaces it with an implant. It is decided according to how much the cataract bothers you and to the medical context, without systematically waiting for a very advanced cataract.

The usual technique uses a small incision, then fragmentation and aspiration of the lens, often with ultrasound. A femtosecond laser can assist certain steps in some centres. That possibility does not mean every operation is carried out entirely with a laser, nor that a laser would be essential to a good result.

The improvement also depends on the other structures of the eye. Someone who has both a cataract and a macular disease can benefit from the operation without regaining normal vision. Before consenting, ask how much of your difficulty can be attributed to the cataract and what limitation might remain. The assessment, the operation itself and recovery are set out in our article on the cataract operation.

Glaucoma and retina: operations that preserve vision

Glaucoma calls for an individual pressure target

Glaucoma damages the optic nerve. Raised intraocular pressure is a major risk factor, but pressure and glaucoma are not synonymous. Treatments seek to slow the deterioration by lowering pressure towards a target suited to each eye. They do not restore nerve fibres that have already been destroyed.

Depending on the type of disease and how it progresses, treatment can use eye drops, a laser or surgery. Filtering procedures create a drainage route for the fluid inside the eye; other techniques use drainage devices. Some less invasive procedures suit particular indications. Further treatment and check-ups remain possible after the operation. The National Eye Institute points out that the aim is to protect the vision that remains.

A retinal disease does not always call for the same operation

The retina can be affected by a detachment, a complication of diabetes or a disease of the macula. Some situations call for monitoring, injections or a laser; others require surgery. Vitrectomy removes the gel inside the eye in order to treat certain lesions. The exact treatment depends on the diagnosis and on the extent of the damage.

A retinal detachment is an ophthalmic emergency. New flashes of light, a sudden increase in floaters or a curtain across the field of vision should prompt you to seek advice quickly. When gas is used during retinal surgery, specific instructions about position and travel may apply. Flying is forbidden for as long as a gas bubble remains inside the eye, until the specialist gives clearance. This restriction cannot be replaced by a standard length of stay. The NEI information on retinal detachment describes these treatments and constraints.

Eyelids, squint and cornea: other specialties to distinguish

Oculoplastic surgery covers the eyelids, the tear ducts and the orbit. Watering caused by an obstruction, an eyelid in the wrong position and excess skin are not treated by the same operation. The examination has to establish the consequences for the ocular surface and for vision, as well as the functional and aesthetic objectives.

Squint surgery acts on the muscles that direct the eyes. It seeks to improve their alignment in a context specific to each patient. Any amblyopia, meaning vision that has not developed sufficiently in one eye, requires a separate assessment. Straightening an eye does not guarantee that its visual acuity will recover, or that binocular vision will be normal.

Finally, corneal diseases can require specialist treatment, sometimes a graft. This pathway is distinct from a laser meant to correct sight. If a cornea is irregular or changing, the first question concerns its health and its stability. The possibility of reducing your glasses comes afterwards, when that remains compatible with the safety of the eye.

What the pre-operative assessment must establish

Before the consultation, note the tasks that have become difficult and the situations in which your glasses genuinely get in the way. Say whether the problem affects one eye or both, how long it has been developing and whether the difficulty varies with the light. This description helps to set a vision measurement against your daily life. It also helps to separate a comfort objective from a gradual loss of vision whose cause needs treating.

The assessment begins with your symptoms, your previous corrections and your medical history. Mention the treatments you use, any general illness, a possible pregnancy, previous operations and any episode of eye infection or inflammation. Bring whatever reports you have: earlier refractive surgery, for example, can change the calculation for a future cataract implant.

The examination measures vision with and without correction and looks for the causes of any limitation. Pressure, the ocular surface, the lens and the back of the eye are assessed according to the indication. Corneal mapping is essential before many refractive procedures. Biometry serves to calculate the power of an implant. These examinations are not simple formalities preceding a technique that has already been chosen.

Wearing contact lenses can influence corneal measurements. The team will tell you how long to stop them before the assessment, with an interval that depends on their type and on your situation. If the measurements are inconsistent or the ocular surface is damaged, it may be better to treat first and measure again. Postponing then improves how reliable the decision will be.

Finally, ask for a realistic estimate of the result in your usual activities. Reading letters well in the consulting room does not fully describe night vision, contrast or lasting comfort in front of a screen. The answers should include the likelihood of still needing a correction and the options available if the result differs from the objective.

Risks, recovery and warning signs

The risks vary with the operation. After corneal laser surgery, they involve dryness, problems with visual quality, a residual correction or a corneal complication. After intraocular surgery, infection, marked inflammation, a change in pressure or a retinal complication are possible. Rare complications can cause lasting loss of vision.

The FDA stresses that glasses may still be needed after LASIK, and that certain visual symptoms or dryness can persist. Consent must set out these limits before the operation. An enhancement is not always possible, and it is never an automatic answer to dissatisfaction.

Post-operative care often includes eye drops and several check-ups. The treatment, the restrictions on sport, the protection against rubbing and the date you go back to work depend on the procedure performed. Driving requires sufficient vision and medical clearance suited to your situation. Being allowed home does not mean you can drive yourself.

Increasing pain, a drop in vision, marked redness or new retinal symptoms must be reported immediately. Keep a number for reaching the team, along with the details of an eye unit you can reach in an emergency. Exchanging messages or photographs can give some guidance, but it does not replace an examination when a complication is suspected.

Cost and organisation of an eye operation

A useful quote identifies the operation, the eye concerned, the fees, any device involved and the check-ups. For an implant, its type and any supplements have to be explicit. For a laser, check whether the price covers one eye or both, which consultations are planned, and on what terms a further correction could be considered.

In France, the rules on cover depend on whether the procedure is therapeutic or refractive, and on your own insurance. The Hospices civils de Lyon state that refractive surgery is not reimbursed by the French state health insurance, with a possible contribution from top-up insurance depending on the policy. Cataract surgery follows a different framework there, and the fees or options are not necessarily all covered. Have your remaining cost confirmed before you fix the date.

If you are considering an operation abroad, the arrangements have to allow for the final assessment, for the possibility of being turned down on medical grounds, and for the check-ups needed before you travel home. Ask who will examine you after the trip and how the reports will be passed on. For an implant, keep its reference; for a laser, keep the pre-operative data and a record of the treatment carried out. This information will be useful throughout your ophthalmic life.

The final choice therefore brings together a medically justified indication, an understandable explanation of the alternatives and follow-up that can realistically be delivered. You need to be able to accept residual glasses, a longer recovery than expected, or even no operation at all if those options protect your vision better. The benefit that counts is the one that matches your eye and your needs, with limits you have been able to examine before deciding.

Sources

1. Hospices civils de Lyon. (2026, February 23). Chirurgie réfractive de l’œil.
2. Hôpitaux universitaires de Genève. (2025, May 6). Chirurgie réfractive : les techniques chirurgicales.
3. Société française d’ophtalmologie. (2026). Chirurgie réfractive cornéenne au laser. Fiche d’information 9A.
4. European Society of Cataract and Refractive Surgeons. (n.d.). Chirurgie de la cataracte.
5. National Eye Institute. (2026, August 20). Glaucoma surgery.
6. National Eye Institute. (2024, December 6). Surgery for retinal detachment.
7. U.S. Food and Drug Administration. (n.d.). What are the risks and how can I find the right doctor for me?.