The pre-operative assessment for cataract surgery

Should you have surgery now

A cataract is not operated on because it is there, but because it gets in your way. There is no benefit in waiting until it is “ripe”: that idea belongs to a time when techniques were different. Conversely, operating on an early cataract that causes no trouble means taking a risk for nothing in return.

What matters is your daily life: night driving that has become difficult, reading that is a strain despite up-to-date glasses, colours that look yellowish, glare in sunlight. The visual acuity measured counts for less than the difficulty you describe.

Biometry, the key test

This is the measurement that determines the power of the lens implant. It combines the axial length of the eye, the curvature of the cornea and the depth of the anterior chamber. These values are fed into a calculation formula that predicts the power needed to reach the target refraction.

The whole result depends on the accuracy of this step. A calculation error leaves a residual prescription after the operation, and you would then have to wear the glasses you were hoping to do without.

What else is examined

The macula, with OCT

A cross-sectional scan of the centre of the retina looks for AMD (age-related macular degeneration), oedema or an epiretinal membrane. The result affects both the choice of lens implant and the visual outcome that can be predicted. Discovering macular disease after the operation, when it is the reason for disappointing vision, is a situation to avoid.

The corneal endothelium

The innermost layer of the cornea keeps it clear, and its cells do not regenerate. A low cell count (cornea guttata, previous surgery) calls for specific precautions during the operation and changes the information you are given.

Intraocular pressure and the optic nerve

Coexisting glaucoma changes two things: it rules out certain lens implants, and it opens up the option of a combined procedure, since cataract surgery itself lowers the pressure.

Corneal topography

It measures the actual corneal astigmatism, which decides whether a toric lens is worthwhile. The figure on your glasses prescription is not enough: it includes the share due to your natural lens, and that share will disappear.

Choosing the lens implant

The decision is made in two stages. First, the measurements rule out what is not possible: a fragile macula, a damaged optic nerve or an irregular cornea closes the door to premium lens implants. Only then do your habits come in. Do you read a lot, drive at night, work on a screen? Would you accept reading glasses?

The four families are described here: monofocal, toric, extended depth of focus, multifocal.

What you leave with

A date, a chosen lens implant, an expected result stated without overestimating it, and a written quote that separates the reimbursed portion, the additional fees above the national tariff and any supplement for the lens implant. Enough to check with your top-up health insurer (mutuelle) before you commit.