Phacoemulsification and intraocular lenses

When it is worth discussing surgery

• Reading, driving or TV limited by blur or glare
• Oncoming headlights at night affecting driving safety
• High hyperopia with a narrow angle
• Cataract blocking monitoring of diabetic retinopathy or macular disease

Do you have to wait until it is “ripe”? (a common myth)

In public education, “wait until the cataract is fully ripe / the eye is completely cloudy before surgery” is mostly an older idea, not a general rule in the phaco era. More usual discussion points are whether the cataract already limits reading, driving, night glare, work or fall risk; whether it blocks monitoring of diabetic eye disease or macular disease; and whether a thickening lens adds to narrow-angle risk — decided only after an ophthalmologist examines you. This page does not say “everyone must operate now” or “everyone must wait longer.”

When a lens is hypermature, extremely hard, or the zonules are unstable, surgery can be harder and some complication risks can rise (an education concept, not your personal odds). “Waiting until it is too ripe” is not necessarily safer; conversely, if vision is still adequate and daily life is unhindered, that does not mean surgery must happen immediately. Whether and when to operate is not an advertising timetable.

Before the operation

• Optical biometry of axial length, keratometry and chamber depth; very dense cataracts may need ultrasound axial length
• IOL power calculation — the formula depends on the eye, not one formula for all
• Ocular surface, IOP, endothelium, fundus when visible, glaucoma or macular disease
• Dilation and antiseptic. Whether to pause an anticoagulant is a joint decision — this page does not give a blanket rule

Usual procedure in Hong Kong: phacoemulsification

A consent-style outline, not a clinic’s private protocol. Incision, energy and anaesthesia depend on the nucleus, cornea and general health.

The order of the day, and the diagrams, are on The day of cataract surgery and lens implantation. The lines below keep the consent-style class outline.

1. Anaesthesia: usually topical drops, sometimes with intracameral anaesthetic; sedation if needed; general anaesthesia for children or special anatomy
2. Dilute iodine on the conjunctiva and lids (an alternative if iodine-allergic); drape and speculum
3. Clear-corneal main incision about 2.2–2.7 mm plus a side port; often no suture
4. Viscoelastic to protect the endothelium and hold the chamber
5. Continuous curvilinear capsulorrhexis — a round window in the anterior capsule
6. Hydrodissection to free the nucleus
7. Ultrasound emulsifies the nucleus into small fragments and aspirates them
8. Femtosecond laser–assisted cataract surgery (FLACS) is another option: laser may assist capsulorrhexis, nucleus fragmentation or incisions, then phaco usually still removes the nucleus. Not everyone needs it. FACT (Day et al., Ophthalmology 2020) was a randomised noninferiority trial: primary vision outcomes versus standard phaco did not show a clinical advantage that would justify writing femto as a “standard upgrade.” FEMCAT (Schweitzer et al., Lancet 2020) was a multicentre randomised trial: superiority was not met, and cost-effectiveness did not support routine universal use. Those are named-trial results — not your personal prognosis, not a clinic or device-brand comparison, and not an advert that femto is “safer / always better.”
9. Aspiration of remaining cortex
10. A foldable lens is injected into the bag and centred
11. Viscoelastic is removed; the wound is hydrated (occasionally one suture)
12. Some centres give an intracameral antibiotic. Postoperative steroid, NSAID and/or antibiotic drops are prescribed individually

Uncomplicated cases often take about 15–30 minutes. Most people go home the same day. Vision usually settles over days to weeks — not “surgery’s done and vision’s a perfect hundred.”

Other operations still discussed

• Extracapsular extraction: a larger wound delivering the whole nucleus — dense nuclei, weak zonules or limited equipment; sutures needed
• Lensectomy via the pars plana when combined with vitreous surgery

Optical classes of lens (not a brand pitch)

Complication figures from the literature (not any clinic’s success rate)

The ranges below are education-only ballparks; this page’s bibliography (the ESCRS endophthalmitis prophylaxis trial) does not map each row to a percentage. A harder nucleus, trauma, pseudoexfoliation, high myopia, a hypermature lens or combined vitreous surgery raise risk. These figures cannot predict one person, and they are not any clinic’s success rate.

Also possible in the first days (most can be managed)

• Transient corneal oedema, foreign-body sensation, photophobia
• A short IOP rise (retained viscoelastic, inflammation or steroid response)
• Wound leak or iris prolapse — uncommon; may need a suture
• Hyphaema, iris trauma, zonular dialysis, a decentred lens
• Refractive surprise: glasses, a contact lens, and rarely lens exchange or corneal laser — individual
• Negative dysphotopsia (a temporal shadow): seen in early literature; most ease over weeks to months
• Toxic anterior segment syndrome: rare sterile inflammation, must be distinguished from infection

Years later: posterior capsule opacification (not a returning cataract)

The implant stays in the original bag. Lens epithelial cells can cloud the posterior capsule over years (PCO, sometimes called an after-cataract). A systematic overview pooled roughly 12% at 1 year, 21% at 3 years, and 28% at 5 years (Schaumberg et al., Ophthalmology 1998; mostly Nd:YAG / discission definitions); a large modern UK registry shows a similar rise with time (RCOphth NOD Report 9, Eye 2023). These are not your personal odds — rates vary with lens, surgery and how PCO is counted. This is not a new lens growing back, and it is not a failed operation.

Blur years after cataract surgery is usually PCO, not a “returning cataract”. Not every blur needs YAG capsulotomy. A doctor must judge whether it affects function and exclude macular, corneal or other causes. The laser is outpatient, with no incision. See the YAG fact sheet. The order of the day is on The day of posterior capsulotomy.