Phacoemulsification: How Modern Cataract Surgery Works

Phacoemulsification is the standard technique used in modern cataract surgery. It uses ultrasound energy delivered through a small self-sealing incision to break up and remove the clouded natural lens. Understanding what actually happens in theatre helps patients approach surgery with accurate expectations about the procedure, the anaesthesia, and the recovery.

What Is Phacoemulsification?

Phacoemulsification is a technique for removing a cataract through a small self-sealing corneal incision — typically 2.2 to 2.8 millimetres — using ultrasound energy to emulsify the clouded lens into fragments that can be aspirated from the eye. Because the incision is small and seals without sutures, patients recover more quickly and with less induced astigmatism than with older large-incision techniques.

The name comes from the Greek phakos (lens) and the process of emulsification — using energy to reduce a solid to a fine suspension that can be aspirated. The technique was introduced by Charles Kelman in 1967 and has since become the dominant approach to cataract surgery worldwide. In Australia, phacoemulsification accounts for the substantial majority of cataract procedures performed each year.

The key advantage of phacoemulsification over earlier extracapsular extraction techniques is the size of the incision required. Large-incision extracapsular surgery required a wound of 10 to 12 millimetres and multiple sutures; phacoemulsification is performed through incisions of 2.2 to 2.8 millimetres that are self-sealing and require no sutures. This reduces surgically induced astigmatism, shortens recovery, and lowers the risk of wound-related complications.

What Is a Cataract?

A cataract is a clouding of the eye's natural crystalline lens, which sits behind the iris and focuses light onto the retina. When proteins within the lens degrade — most commonly with age — the lens gradually loses transparency. Glare, halos around lights, faded colours, and increasing difficulty reading in low light are characteristic early symptoms.

The natural crystalline lens is a transparent biconvex structure approximately 9 millimetres in diameter and 4 millimetres thick. It is suspended behind the iris by a ring of fine fibres (zonules) attached to the ciliary body. Lens transparency depends on the precise arrangement of structural proteins called crystallins. With ageing, ultraviolet exposure, or systemic conditions such as diabetes, crystallins denature and aggregate — producing the clouding that defines a cataract.

Nuclear cataracts — the most common type — involve yellowing and hardening of the central lens nucleus. Cortical cataracts produce spoke-like opacities in the outer lens layers. Posterior subcapsular cataracts develop at the back of the lens and cause particular difficulty with near vision and with glare in bright light. Many patients have mixed cataracts with features of more than one type. For a detailed patient guide to cataract types and indications for surgery, see corneaeyedoctor.com/cataract-surgery/.

How Phacoemulsification Works — Step by Step

Phacoemulsification involves eight sequential steps from anaesthesia to IOL implantation, all performed under an operating microscope through incisions measuring a few millimetres. The procedure typically takes 15 to 30 minutes for a routine case, though complex cataracts require additional time and technique adjustments.

1. Anaesthesia

Cataract surgery in Australia is performed under topical anaesthesia — anaesthetic drops placed on the ocular surface — in the great majority of cases. Topical anaesthesia avoids the risks of sharp needle injections around the eye while providing adequate anaesthesia for the procedure. Patients remain awake throughout; some experience mild pressure or light sensitivity, but sharp pain is not expected and can be addressed with supplemental anaesthesia. Intravenous sedation is available for patients with significant anxiety.

2. Incisions

Two small incisions are made in the peripheral cornea or at the limbus (the corneal-scleral junction). The main phaco incision — 2.2 to 2.8 millimetres — accepts the phacoemulsification handpiece. A smaller paracentesis incision of approximately 1.0 millimetre provides access for a second instrument used to stabilise and manipulate lens fragments during surgery. Both incisions are self-sealing and do not require sutures in routine cases.

3. Capsulorhexis

The anterior lens capsule — the thin transparent envelope surrounding the lens — is opened with a continuous curvilinear capsulorhexis (CCC). A needle or capsule forceps creates a smooth, circular opening of approximately 5 to 5.5 millimetres in diameter. The size and centration of the capsulorhexis are critical: the opening must be large enough to allow phacoemulsification and IOL implantation, yet small enough that the capsule edge overlaps the IOL optic — a configuration that reduces the risk of posterior capsule opacification. The posterior capsule is left intact throughout the procedure to support the IOL.

4. Hydrodissection

A blunt cannula injects balanced salt solution beneath the anterior capsule, separating the lens cortex from the capsule and allowing the nucleus to rotate freely within the capsular bag. This step is essential for safe phacoemulsification: a mobile nucleus can be rotated and cracked without placing traction on the zonular fibres that suspend the lens.

5. Phacoemulsification

The phacoemulsification handpiece delivers ultrasound energy through a hollow titanium needle vibrating at approximately 40,000 cycles per second. This vibration emulsifies the lens nucleus into small fragments, which are simultaneously aspirated through the needle by a pump system. The surgeon uses a second instrument through the paracentesis to manipulate and stabilise lens fragments. Various disassembly techniques are used depending on nuclear density — including divide and conquer, phaco chop, and stop-and-chop. Minimising cumulative ultrasound energy is important as it is the primary determinant of endothelial cell loss during the procedure.

6. Cortex Removal

After the nuclear fragments are removed, the remaining softer cortical material is aspirated from the capsular bag using an irrigation-aspiration (I/A) handpiece. Thorough cortex removal reduces post-operative inflammation and lowers the risk of posterior capsule opacification. Care is taken to protect the posterior capsule during this step, as any tear in the posterior capsule is the most common intraoperative complication of phacoemulsification and may alter the planned approach to IOL implantation.

7. Viscoelastic Injection

An ophthalmic viscosurgical device (OVD) — a clear viscoelastic gel — is injected into the capsular bag to maintain its shape and protect the corneal endothelium during IOL insertion. OVDs are removed completely at the end of surgery; retained viscoelastic is a cause of early post-operative intraocular pressure elevation.

8. IOL Implantation

An intraocular lens is folded and loaded into an injector cartridge, then deployed through the main incision into the capsular bag. Most modern IOLs are made from acrylic and are designed to unfold slowly within the capsule. The haptics — the flexible positioning arms of the IOL — centre the optic within the bag, where it remains permanently. The incision seals by hydration of the wound lips; no sutures are required in the majority of cases.

What Makes a Cataract Complex?

A dense brunescent nucleus, a poorly dilating pupil, weakened zonular fibres (as in pseudoexfoliation syndrome), prior refractive surgery, or pre-existing corneal disease each increase surgical complexity and require technique adjustments. These factors affect surgical planning, IOL selection, and in some cases whether the procedure should be performed at a centre with corneal or vitreoretinal backup.

Most cataract procedures in fit patients with healthy eyes are technically straightforward, but a proportion require additional planning and technique modifications. Factors that increase surgical complexity include:

• Dense or brunescent nuclei — a very hard nucleus requires higher phacoemulsification energy and may need modified cracking techniques to disassemble efficiently.
• Small or poorly dilating pupil — limited pupil dilation (less than approximately 5 millimetres after pharmacological dilation) reduces visualisation and surgical access. Pupil expansion devices or iris hooks may be required.
• Pseudoexfoliation syndrome — a condition in which flaky material deposits on anterior segment structures and weakens the zonular fibres that suspend the lens. Zonular weakness increases the risk of lens instability or posterior capsule rupture during surgery.
• Prior intraocular surgery or trauma — previous vitreoretinal surgery, penetrating trauma, or prior anterior segment surgery may alter anatomy and increase complication risk.
• Pre-existing corneal disease — conditions such as Fuchs endothelial dystrophy limit endothelial cell reserve, making efficient, low-energy technique particularly important. In selected cases, combined cataract and DMEK corneal transplantation is planned as a single procedure.
• Prior refractive surgery — LASIK, PRK, or SMILE alter corneal curvature and refractive index, making IOL power calculation less predictable. Specialised formulae and additional biometric measurements are used in these eyes.

Recovery After Phacoemulsification

Phacoemulsification is a day procedure. Many patients notice improved clarity within 24 to 48 hours of surgery. Vision continues to settle over the following days to weeks as post-operative inflammation resolves. Post-operative drops — typically a topical antibiotic and an anti-inflammatory — are used for several weeks. Strenuous activity, swimming, and rubbing the eye should be avoided during the healing period.

Post-operative instructions include:

• Use prescribed antibiotic and anti-inflammatory drops as directed — typically for three to four weeks
• Wear a protective shield over the operated eye while sleeping for the first one to two weeks
• Avoid rubbing the eye, as this can stress the self-sealing corneal wound
• No swimming or water sports for two to four weeks
• Avoid strenuous physical activity or heavy lifting for the first week
• Attend the first post-operative review — usually within the first few days

Final visual acuity is typically assessed at the four to six week post-operative appointment. A spectacle update — if needed — is best deferred until this point, as the refraction can shift slightly while the eye is healing.

Posterior Capsule Opacification

Posterior capsule opacification (PCO) — sometimes called a secondary cataract — is the most common late complication of cataract surgery. Residual lens epithelial cells migrate onto the posterior capsule and cause it to become progressively cloudy over months to years. PCO is treated permanently with YAG laser capsulotomy — a brief outpatient laser procedure requiring no incision, taking only a few minutes, with immediate visual improvement.

Symptoms of PCO are similar to those of the original cataract: blurred vision, glare, and reduced contrast sensitivity. YAG laser capsulotomy creates a small opening in the clouded posterior capsule using a focused laser beam. The procedure is painless and requires no recovery time. IOL design influences PCO rate: square-edge IOL optics create a mechanical barrier that reduces lens epithelial cell migration onto the capsule.

Cataract Surgery in Melbourne

Dr Ross MacIntyre performs phacoemulsification at Northpark Private Hospital (135 Plenty Road, Bundoora) and at Bass Coast Eye Centre (212 Graham Street, Wonthaggi). Consultations are available at Northern Eye Consultants, Suite 5, Northpark Hospital Consulting Rooms, Bundoora. For complex cataracts requiring corneal or vitreoretinal support, he also holds a public appointment at the Royal Victorian Eye and Ear Hospital. Referrals can be made via HealthLink EDI nthneyec or by calling (03) 9466 8822.

Dr Ross MacIntyre BA (Chemistry) MD FRANZCO is a cataract, corneal and refractive surgeon practising in Melbourne. He completed subspecialty fellowship training in cornea, complex cataract and refractive surgery at the Wilmer Eye Institute, Johns Hopkins University, and holds a public appointment at the Royal Victorian Eye and Ear Hospital. Dr MacIntyre is the author of Seeing Clearly, a patient guide to cataract surgery. For a complete overview of cataract surgery and intraocular lens options, see corneaeyedoctor.com/cataract-surgery/.