What Is a Cataract?
A cataract is a clouding of the natural crystalline lens inside the eye. The lens sits behind the iris (the coloured part of the eye) and focuses light onto the retina. When the lens becomes opaque, light is scattered and blocked, resulting in blurred vision, glare, difficulty with night driving, and faded colours.
Cataracts are overwhelmingly age-related — by age 70, most people have some degree of lens opacity. However, certain conditions accelerate cataract formation significantly, and this is where Dr. Wong's expertise becomes particularly relevant:
- Previous vitrectomy surgery — approximately 85% of phakic (natural lens) eyes develop visually significant cataract within 5 years of vitrectomy
- High myopia — highly myopic eyes (≥ –6.00 dioptres) develop cataracts earlier and present unique surgical challenges due to altered anatomy
- Trauma — blunt or penetrating eye injury can damage the lens capsule, causing rapid cataract formation
- Steroid use — long-term corticosteroid use (oral, inhaled, or eye drops) causes posterior subcapsular cataracts
- Diabetes — diabetic patients develop cataracts earlier and more frequently
How Cataract Surgery Works
Modern cataract surgery uses a technique called phacoemulsification — an ultrasound-powered probe breaks up the cloudy lens into tiny fragments that are then aspirated from the eye. An artificial intraocular lens (IOL) is implanted in the now-empty capsular bag to restore focusing power.
Anaesthesia
Most cataract surgery is performed under topical anaesthesia (numbing eye drops) with light sedation. You are awake but comfortable. General anaesthesia is rarely needed and reserved for patients who are unable to cooperate.
Corneal incision
A tiny incision (2.2–2.75 mm) is made at the edge of the cornea. This self-sealing wound typically requires no stitches. The site and design of this incision is critically important — it must be constructed carefully to maintain wound integrity, particularly in combined phaco-vitrectomy where the eye will undergo further manipulation during the vitrectomy portion of surgery.
Capsulorhexis
A circular opening is made in the anterior capsule of the lens (the thin membrane enclosing the cataract). The size of this opening is critical — it should overlap the edge of the IOL optic (typically ~5 mm diameter for a standard 6 mm lens) to prevent forward movement of the IOL after surgery, which is particularly important if gas tamponade is used in combined phaco-vitrectomy.
Phacoemulsification
The ultrasound probe is inserted through the incision and used to fragment and aspirate the cataract. Nucleus removal is performed with the lowest possible ultrasound energy and as far from the corneal endothelium as possible to maintain corneal clarity — especially important in combined procedures where a clear cornea is needed for subsequent vitrectomy visualisation.
IOL implantation
A foldable artificial lens is injected through the small incision and unfolds inside the capsular bag, replacing the cloudy natural lens. The IOL provides permanent focusing power. For patients requiring combined phaco-vitrectomy, the timing of IOL insertion relative to vitrectomy is an important surgical decision (discussed below).
Wound closure
The corneal incision is sealed using stromal hydration (injecting fluid into the wound edges). Stitches are rarely required for routine cases. Proper wound stability is verified by confirming a stable anterior chamber and IOL position.
Procedure duration
Standard phacoemulsification takes 15–30 minutes. Complex cases (dense cataracts, weak zonules, post-vitrectomy eyes) may take 30–45 minutes. Combined phaco-vitrectomy takes 60–90 minutes total.
Complex Cataracts: When Standard Surgery Isn't Enough
While most cataract surgery is routine, certain clinical scenarios transform it into a technically demanding procedure that requires subspecialist expertise. Dr. Wong's dual training as a vitreoretinal surgeon and cataract surgeon makes him uniquely qualified to manage these challenging cases.
Cataracts in Post-Vitrectomy Eyes
Cataract development after vitrectomy is almost inevitable in phakic eyes. The vitreous gel normally acts as a metabolic buffer — once removed, the higher oxygen levels in the vitreous cavity accelerate oxidative damage to the lens proteins, causing rapid cataract formation. Gas tamponade during vitrectomy further accelerates this process.
Cataract surgery in post-vitrectomy eyes is more challenging than routine surgery for several reasons:
- Altered fluid dynamics — without the vitreous gel, the posterior segment behaves differently during surgery. The absence of vitreous support means the posterior capsule can trampoline (move unpredictably forward and backward), increasing the risk of posterior capsular rupture
- Zonular weakness — prior vitrectomy, particularly with extensive manipulation or gas tamponade, can weaken the zonules (the fine fibres suspending the lens), leading to instability during surgery
- Deep anterior chamber changes — the eye's internal pressure dynamics are altered, making the surgical environment less predictable
- Inaccurate biometry — the change in vitreous composition after vitrectomy can affect axial length measurements and IOL power calculations, potentially leading to refractive surprises if not accounted for
- Higher risk of IOL dislocation — post-vitrectomy eyes have a higher long-term risk of IOL subluxation, especially if zonular integrity was compromised
Why a vitreoretinal surgeon for post-vitrectomy cataracts?
A vitreoretinal surgeon performing cataract surgery in a post-vitrectomy eye has a critical advantage: they understand the posterior segment anatomy intimately, can anticipate and manage complications like capsular rupture with lens fragment drop, and are prepared to perform additional vitrectomy if needed — all in a single operative session.
Cataracts in Highly Myopic Eyes
High myopia (≥ –6.00 dioptres or axial length ≥ 26 mm) presents a distinct set of challenges for cataract surgery that extend beyond the lens itself:
- Longer axial length — the elongated eye means the posterior capsule is further from the surgeon, requiring adjusted technique. Very long eyes (axial length > 30 mm) have proportionally thinner sclera and altered geometry
- Zonular fragility — highly myopic eyes may have stretched, weakened zonules due to the enlarged globe. This increases the risk of zonular dialysis during surgery
- IOL power calculation challenges — very low or negative IOL powers are sometimes required for extremely myopic eyes. Standard formulas become less accurate at extreme axial lengths, and newer formulas (Barrett Universal II, Kane) are preferred
- Increased retinal detachment risk — cataract surgery in highly myopic eyes carries an elevated risk of subsequent retinal detachment (up to 2–3% in very high myopia versus 0.5% in normal eyes). This is why postoperative monitoring by a vitreoretinal specialist is essential
- Pre-existing retinal pathology — many highly myopic eyes already have peripheral retinal degenerations, lattice degeneration, or thin areas that may need prophylactic laser treatment before or at the time of cataract surgery
- Deep anterior chamber — while this provides more surgical working space, it also changes the hydrodynamic behaviour during phacoemulsification
2–3×
Higher retinal detachment risk after cataract surgery in highly myopic eyes
Postoperative retinal surveillance by a vitreoretinal specialist is essential
For patients with high myopia who have pre-existing retinal conditions (myopic macular degeneration, peripheral retinal degenerations, prior retinal detachment repair), having a vitreoretinal surgeon manage the entire surgical pathway — from cataract extraction to long-term retinal monitoring — provides continuity of care across both the anterior and posterior segment. For a comprehensive discussion of how high myopia affects the eye beyond just the need for glasses, see our article on high myopia and the retina.
Other Complex Cataract Scenarios
- Posterior polar cataracts — a congenital opacity at the very back of the lens, intimately adherent to the posterior capsule. There is a high risk of capsular rupture and nucleus drop. Planning an elective phacoemulsification with readiness for possible vitrectomy is the optimal approach — the surgeon and operating suite are prepared for quick conversion if vitrectomy becomes necessary
- Subluxated or dislocated lenses — from trauma or conditions like Marfan syndrome, pseudoexfoliation, or prior surgery. These may require capsular tension rings, iris hooks, or combined vitrectomy approaches
- Dense white (mature) cataracts — require trypan blue staining of the anterior capsule to visualise the capsulorhexis, and generate higher ultrasound energy requirements
- Cataracts with concurrent retinal pathology — when a patient needs both cataract removal and retinal surgery, combined phaco-vitrectomy is often the optimal approach
Combined Phaco-Vitrectomy: Two Surgeries in One
Combined phacoemulsification and vitrectomy (phaco-vitrectomy) is one of Dr. Wong's areas of particular expertise. This approach combines cataract removal with vitreous surgery in a single operative session, offering significant advantages for appropriate patients.
When is phaco-vitrectomy indicated?
Combined surgery is ideally suited in phakic eyes of older patients where vitrectomy is required for relatively uncomplicated retinal or vitreous pathology. Typical indications include:
- Macular conditions — macular holes, epiretinal membranes, vitreomacular traction, myopic macular retinoschisis
- Vitreous haemorrhage — from proliferative diabetic retinopathy, retinal vascular disease, or breakthrough haemorrhage in wet AMD
- Retinal detachment — in older patients where cataract would otherwise obscure the view and accelerate post-vitrectomy anyway
Combined vs Sequential Surgery
- Advantages: Single surgery, single anaesthetic, single recovery period. Removes cataract that would otherwise form after vitrectomy (~85% within 5 years). Provides excellent surgical access to the peripheral retina and vitreous base. Cost-effective — approximately 17% cost savings compared to sequential approach
- Best for: Older patients with existing or early cataract who need macular surgery, vitreous haemorrhage clearance, or uncomplicated retinal detachment repair
- Considerations: Slightly higher risk of posterior synechiae and pupil capture of IOL, particularly with gas tamponade. IOL power calculation may be less precise in the presence of retinal pathology
- Advantages: More accurate IOL biometry after retinal anatomy has stabilised. Lower risk of iris complications. In epiretinal membrane cases, cataract surgery alone may sufficiently improve vision — one study found 17% of patients did not subsequently need vitrectomy
- Best for: Younger patients where preserving the natural lens is important. Severe proliferative vitreoretinopathy. Complex diabetic traction detachments. Cases where retinal anatomy needs to stabilise before reliable biometry
- Considerations: Requires two separate surgeries, two anaesthetics, and two recovery periods. Higher total cost and more time off work
Surgical technique: phaco-vitrectomy pearls
Several technical refinements make the combined procedure safe and effective:
- Port placement first — vitrectomy ports (trocars) are placed before phacoemulsification. This prevents anterior chamber shallowing during trocar insertion and allows endoillumination if the cataract is too dense for a standard red reflex
- Meticulous wound construction — the corneal incision must be watertight before proceeding to vitrectomy, as any leakage during vitrectomy manipulation compromises both anterior chamber stability and IOL position
- Low-energy phacoemulsification — nucleus removal is performed with minimal ultrasound energy to preserve corneal clarity for the subsequent vitrectomy, where a perfectly clear view of the retina is essential
- Capsulorrhexis sizing — slightly smaller than usual (~5 mm) to ensure the capsule edge overlaps the IOL optic, reducing the risk of IOL displacement with gas tamponade
- IOL timing decision — the lens can be implanted immediately after phacoemulsification or deferred until the end of vitrectomy. For straightforward macular surgery, immediate IOL insertion is usually preferred for convenience. If extensive retinal work is anticipated, deferring IOL insertion until after fluid–air exchange may be advisable
For detailed information on vitrectomy technique and recovery, see our comprehensive guide to vitrectomy surgery.
Choosing the Right Intraocular Lens
The intraocular lens (IOL) implanted during cataract surgery is a permanent replacement for your natural lens. There are several categories, each with distinct advantages:
Monofocal IOL
Provides excellent vision at a single focal point — typically set for distance. Most patients will need reading glasses for near tasks. This is the most widely used lens type worldwide, with decades of proven safety and optical quality. Ideal for patients who are comfortable with reading glasses and want the most predictable outcome.
Extended Depth of Focus (EDOF)
Provides a continuous range of vision from distance through intermediate (computer, dashboard) with minimal optical disturbance. Unlike multifocal lenses that split light into distinct zones, EDOF lenses elongate the focal point for a smoother visual experience — resulting in excellent contrast sensitivity with less glare and haloes. Many patients achieve good functional near vision for reading, though some may still prefer reading glasses for prolonged fine print.
Multifocal IOL
Splits incoming light into two or more focal points, providing simultaneous distance and near vision and reducing dependence on reading glasses. Best suited for healthy eyes with minimal corneal irregularity and no retinal pathology. Not recommended for eyes with high myopia, macular degeneration, epiretinal membrane, or other retinal pathology — the multifocal optic reduces contrast sensitivity, which is poorly tolerated when retinal function is already compromised.
Toric IOL
Corrects pre-existing corneal astigmatism at the time of cataract surgery. Available in monofocal and EDOF configurations. Precise alignment during implantation is essential — even a few degrees of rotation reduces the astigmatic correction. Particularly valuable for patients with significant astigmatism who want spectacle independence for distance.
IOL selection in complex cases
For post-vitrectomy eyes and highly myopic eyes, IOL selection requires careful consideration. Monofocal IOLs are generally the safest choice in complex cases because they are the most forgiving of minor refractive surprises. EDOF lenses can be considered in straightforward combined phaco-vitrectomy for macular surgery without gas tamponade, where biometry is reliable. Multifocal IOLs are generally avoided in eyes with pre-existing macular pathology, as the split-light design can reduce contrast sensitivity in eyes that may already have compromised macular function. For vitrectomy eyes where biometry may shift post-operatively, staging the cataract surgery allows more precise lens selection.
Recovery After Cataract Surgery
Recovery from standard cataract surgery is rapid — most patients notice improved vision within 24–48 hours.
Day 1: Immediate Post-operative
Some mild grittiness, tearing, and light sensitivity are normal. Your eye will be slightly red. Vision is already noticeably clearer in most cases, though may be slightly hazy. You will be prescribed antibiotic and anti-inflammatory eye drops. An eye shield is worn at night for the first week to prevent accidental rubbing during sleep.
Week 1–2: Rapid Improvement
Vision continues to improve as the cornea settles and any residual inflammation resolves. Most patients can return to desk work within 2–3 days. Avoid heavy lifting, swimming, and eye rubbing. Your first post-operative review is typically at day 1 and again at 1–2 weeks.
Week 4–6: Stabilisation
By 4–6 weeks, your eye has fully healed and a new spectacle prescription can be measured. If you had combined phaco-vitrectomy with gas tamponade, the gas bubble will have absorbed by this point and your refraction will have stabilised. You can resume all normal activities, including exercise and swimming.
Recovery after combined phaco-vitrectomy
If you had combined phaco-vitrectomy, recovery is determined primarily by the vitrectomy component. If gas tamponade was used, posturing requirements and activity restrictions follow the vitrectomy protocol (see our vitrectomy guide for detailed recovery timelines). Vision improvement is typically more gradual — expect 4–8 weeks for the full visual outcome to emerge as the gas absorbs and the retinal pathology heals.
Risks and Complications
Cataract surgery is one of the safest surgical procedures performed today, with a serious complication rate of less than 1%. However, it is still surgery, and understanding the risks is important:
Posterior capsular opacification (most common)
Over months to years, the capsule behind the IOL can become hazy — sometimes called a "secondary cataract". This affects 10–20% of patients and is easily treated with a painless 30-second YAG laser capsulotomy in the clinic. It does not require repeat surgery.
Infection (endophthalmitis)
Severe eye infection after cataract surgery is rare, occurring in fewer than 1 in 1,000 cases at specialist centres. Symptoms include increasing pain, redness, and vision loss in the days after surgery — this requires urgent treatment.
Retinal detachment
The risk of retinal detachment after cataract surgery is approximately 0.5–1% in normal eyes, but rises to 2–3% in highly myopic eyes. This is why Dr. Wong monitors highly myopic cataract patients with regular retinal examinations postoperatively. Any new flashes of light, floater showers, or shadow in the vision after cataract surgery should be assessed urgently.
IOL dislocation
Late subluxation or dislocation of the IOL can occur months to years after cataract surgery, particularly in eyes with weak zonules (pseudoexfoliation syndrome, high myopia, prior vitrectomy, trauma). This requires surgical repositioning or exchange — a procedure Dr. Wong performs regularly. For more on this, see our article on dislocated intraocular lens surgery.
Cystoid macular oedema
Swelling at the macula can occur a few weeks after cataract surgery, causing temporary blurred central vision. It responds well to anti-inflammatory eye drops in most cases and usually resolves within 2–3 months.
When to seek urgent review after cataract surgery
Contact the clinic immediately if you experience: sudden increase in pain, significant worsening of vision, new floaters or flashes of light, a shadow or curtain in your peripheral vision, or increasing redness with discharge. These symptoms may indicate a treatable complication that requires prompt attention.
Frequently Asked Questions
How much does cataract surgery cost in Singapore?
At private institutions like Gleneagles Hospital, standard cataract surgery typically costs SGD $8,000–$11,000 per eye, depending on the type of intraocular lens chosen and the complexity of the case. Complex cataract cases (post-vitrectomy, high myopia, subluxated lenses) may cost more due to the additional surgical time and expertise required. Medisave can be used to partially offset costs. For detailed pricing, contact the clinic directly.
Is cataract surgery safe for highly myopic eyes?
Yes, but it requires a surgeon experienced with high myopia. Highly myopic eyes have longer axial lengths, deeper anterior chambers, and may have weakened zonules. IOL power calculation is more challenging in very long eyes, and there is a small increased risk of retinal detachment after surgery. With proper technique, appropriate IOL formula selection, and postoperative retinal monitoring by a vitreoretinal specialist, outcomes are excellent.
Why does cataract develop faster after vitrectomy?
Approximately 85% of phakic eyes develop visually significant cataract within 5 years of vitrectomy. This is thought to relate to altered oxygen levels within the eye after vitreous removal — the higher oxygen exposure accelerates oxidative damage to lens proteins. Use of intraocular gas tamponade during vitrectomy further accelerates cataract formation, sometimes within months.
Can cataract surgery and vitrectomy be done at the same time?
Yes. Combined phaco-vitrectomy is a safe and well-established procedure. It is ideally suited for older patients who need vitrectomy for conditions like macular holes, epiretinal membranes, or vitreous haemorrhage. Combining the procedures avoids a second surgery, reduces overall recovery time, and saves approximately 17% in total surgical costs compared to having them done separately. Dr. Wong routinely performs combined phaco-vitrectomy at Gleneagles Hospital.
What type of lens is best for cataract surgery?
The best lens depends on your eyes, your lifestyle, and the overall health of the retina. Monofocal lenses provide excellent distance vision and are the standard choice — most patients will need reading glasses afterwards. Extended depth of focus (EDOF) lenses provide a continuous range of focus from distance through intermediate, with fewer optical side effects than traditional multifocal lenses, and excellent contrast sensitivity. Toric lenses correct astigmatism. Your surgeon will discuss the best option for your specific situation during the consultation.
How long does cataract surgery take?
Standard phacoemulsification takes approximately 15–30 minutes per eye. Complex cases — such as cataracts in post-vitrectomy eyes with altered anatomy, dense white cataracts, or eyes with weak zonules — may take 30–45 minutes. Combined phaco-vitrectomy typically takes 60–90 minutes as both procedures are performed in a single session.
Will I still need glasses after cataract surgery?
This depends on the type of IOL chosen and your refractive goals. With a standard monofocal IOL set for distance, you will need reading glasses for near tasks. An EDOF lens provides a broader range of clear vision, and many patients achieve functional independence from glasses for most daily activities, though some may still prefer reading glasses for sustained fine print. Discuss your visual goals with your surgeon so the right lens can be selected.
Can both eyes be done at the same time?
In most cases, cataract surgery is performed on one eye at a time, with the second eye done 1–2 weeks later. This is primarily a safety measure — if an unexpected complication occurs, the second eye remains unaffected. Bilateral same-day surgery is performed in selected straightforward cases at some centres, but is not standard practice for complex cataract surgery.