How is cataract surgery performed?
Cataract surgery is performed today using phacoemulsification. Through two or three tiny incisions at the edge of the cornea, the clouded lens is broken up with ultrasound energy and removed. A foldable artificial lens, calculated in advance from your eye measurements, is then placed in the natural lens capsule. The incisions usually seal without stitches.
The operation is performed under anaesthetic eye drops: you are awake but should not feel pain — at most a slight sensation of touch or pressure. In experienced hands it takes about 10–15 minutes. Laser-assisted ("femto") cataract surgery offers no additional benefit while increasing duration and cost, so the modern phaco technique is used.
When is surgery needed?
Not every cataract needs immediate surgery. The timing depends on how much the cataract affects your vision and daily life. Surgery is usually planned when you notice:
- clearly reduced vision
- difficulty reading
- worse vision when driving, especially at night
- increasing glare and light scatter
- difficulty watching TV or recognising faces
If surgery is delayed for too long, the cataract hardens and the operation becomes more difficult; in some cases it can also raise eye pressure.
Lens options: monofocal, toric, EDOF and trifocal
- Monofocal lenses: sharp vision at one distance (usually far); reading glasses are needed for near.
- Toric lenses: additionally correct astigmatism.
- EDOF lenses: good far and intermediate vision with less light scatter at night; near vision is partly supported.
- Trifocal (smart) lenses: far, intermediate and near vision — the strongest option for reading without glasses.
Smart lenses can greatly reduce or eliminate the need for glasses, but they cannot guarantee glasses-free vision at every distance for everyone. Careful patient selection and the right lens type are decisive.
Smart lenses without cataract
Smart lenses are also used in people who do not have a cataract:
- people around 45 and older whose near vision has declined (presbyopia) and who want to depend less on reading glasses
- people with high glasses prescriptions who want to be free of them (also called a “permanent lens” or refractive lens exchange)
The surgical technique is the same as in cataract surgery; the difference lies in the lens and in the detailed planning beforehand.
The examination before surgery
Before surgery, both the health of your eye and the power of the new lens are determined:
- vision test and current glasses prescription
- slit-lamp examination of the cornea, iris and lens
- eye pressure measurement
- dilated examination of the retina and optic nerve
- optical biometry to calculate the lens power (ultrasound biometry for very dense cataracts)
- corneal topography and OCT where needed, e.g. for astigmatism or smart lenses
If you wear contact lenses, stop wearing them beforehand so that the measurements are accurate: soft lenses at least 1 week, rigid lenses at least 3 weeks.
Surgery day and recovery
After surgery you rest for about 30 minutes and go home the same day with your eye covered. One hour later you remove the cover and start the eye drops — more often in the first 2–3 days, then less frequently, usually for about one month.
- First 1–2 days: mild grittiness, watering, light sensitivity and slightly blurred vision are normal.
- Vision then becomes progressively clearer; in some patients recovery takes 1–2 weeks longer because of temporary corneal swelling.
- Do not rub your eyes and keep to clean environments, especially in the first 10 days.
- With smart lenses the brain needs time to adapt (neuroadaptation): halos around lights at night may be noticeable for a few weeks to a few months and usually decrease.
- About one month after surgery, your final far and near prescription is checked.
Can both eyes be operated on the same day?
Usually the two eyes are operated on on different days, so that the small risk of infection is not taken in both eyes at once. In certain situations — for example in very elderly patients, serious general health problems or a strong fear of the operating room — both eyes may be operated on the same day.
Risks
Like any operation, cataract and smart lens surgery carries risks. Rarely, infection, changes in eye pressure, retinal problems or clouding of the lens capsule (secondary cataract) may occur; most can be detected early at the check-ups and treated. A secondary cataract can be treated with a short laser procedure. Very rarely a lens may need to be exchanged. A careful examination and an experienced surgeon keep these risks as low as possible.