The cataract, seen from the inside
A human eye measures 24 millimetres. Everything that happens in a cataract takes place inside its natural lens, the size of a lentil.
01 · The eye from outside
From outside you only see the window
The white part is the sclera. In front, the transparent cornea reveals the iris and the pupil. Everything else works hidden behind.
02 · A quarter removed
We take out a quarter
We remove a wedge from the eyeball, like in an anatomy plate, to look inside with nothing in the way.
03 · A healthy eye
Light focuses on the retina
The cornea and the lens bend light onto one very precise point of the retina, the macula. As long as the lens stays clear and flexible, the image arrives sharp.
04 · What a cataract is
The lens loses its clarity
Over the years, the proteins of the lens compact and yellow. A cataract is not a film growing over the eye: it is the lens itself turning opaque.
05 · How it progresses
Early, moderate, mature
At first, oncoming light bothers you and reading gets harder. Later, colours fade and night driving becomes uncomfortable. In the end the lens is so opaque that vision is severely limited.
06 · The operation
A two-millimetre entrance
With anaesthetic drops and the pupil dilated, a micro-incision of about 2 mm is made in the cornea. No stitches: it seals itself.
07 · The capsulorhexis
A window opens in the bag
The lens lives inside a transparent bag, the capsule. A circle is cut in its front face and the rest is preserved: it will house the new lens.
08 · Phacoemulsification
The lens leaves the way it came
An ultrasound tip fragments the cloudy lens and aspirates the pieces through the same 2 mm incision. The bag is left clean and intact.
09 · The intraocular lens
A lens that never wears out
It goes in folded and unfolds inside the bag, where it sits centred and stable. It is permanent and transparent: light focuses on the macula again.
10 · The eye closed
Everything back in place
We close the wedge. Outside, only the 2 mm incision remains, sealing on its own; inside, the lens now sits where the natural one used to be.
Free mode
Explore the model
Rotate the eye by dragging with two fingers or the mouse, and tap any structure to learn what it is.
Illustrative 3D model for information purposes. It does not replace an individual assessment by your ophthalmologist.
Keep going
If cataracts are on your mind, these guides answer what patients usually ask before and after surgery.
Patient guides: Cataract surgery in Madrid · Preparing for surgery · Types of intraocular lenses · The recovery
Also in 3D: glaucoma, from the healthy eye to surgery
Illustrative 3D model for information purposes. It does not replace an individual assessment by your ophthalmologist.
Authorship, medical review and sources
- Author and medical reviewer
- Dr. Francisco Javier Abellán Martínez
- Ophthalmologist · Medical registration no. 282880215
- The same specialist currently authors and medically reviews the content; this is not presented as an independent external review.
- Last medically reviewed
Sources consulted (4)
- ESCRS recommendations for cataract surgery (Opens in a new tab)European Society of Cataract and Refractive Surgeons (ESCRS)
- Cataracts in adults: management (NG77) (Opens in a new tab)National Institute for Health and Care Excellence (NICE)
- Cataract surgery: procedure and recovery (Opens in a new tab)National Health Service (NHS)
- Patient information booklets (Opens in a new tab)The Royal College of Ophthalmologists
General educational content. It does not replace an individual assessment, diagnosis or personalised instructions from your healthcare team.
How these guides are written and reviewed