Intumescent cataract is a complex type of cataract characterized by lens opacification accompanied by swelling (hydration) and increased intralenticular pressure.
Like hypermature cataract, it appears white, but differs by the presence of prominent sectorial markings in the anterior cortex. It may also be associated with capsular fissures.
It can develop after ocular trauma or pars plana vitrectomy (PPV). Traumatic cataracts occur in 5–10% of all eye injuries, and systemic conditions such as diabetes increase the risk of progression to intumescent cataract.
Increased intralenticular pressure and loss of red reflex make surgery more technically demanding than standard cataract surgery. However, with appropriate preoperative evaluation and surgical strategy, good visual recovery can be expected.
Intumescent cataract is characterized by fan-like striae in the anterior cortex, and the lens nucleus often remains without liquefaction. In contrast, hypermature Morgagnian cataract is a condition where the nucleus sinks to the bottom of the liquefied cortex, and movement of the nucleus within the capsule is observed. Intumescent cataract is positioned as an intermediate type between immature cortical cataract and mature cortical nuclear cataract.
In intumescent cataract, visual function is significantly reduced because the opaque lens nucleus blocks light.
Slit-Lamp Microscopy Findings
Tense anterior capsule: The anterior capsule bulges due to increased internal pressure, showing a tense, glossy appearance.
White opaque lens: The cortex becomes cloudy white, and the nucleus blocks the red reflex.
Anterior cortical fan-shaped striae: An important finding for differentiation from hypermature cataract.
Features in traumatic cases: Capsular tears or pigment deposits on the anterior capsule may be observed.
Imaging Findings
AS-OCT findings: Lens thickness ≥5.36 mm and spherical shape suggest intumescent cataract. It is useful for preoperative assessment of swelling and identification of fluid accumulation sites.
Scheimpflug densitometry: High-density findings suggest the presence of a large nucleus.
Loss of red reflex: The opaque nuclear material blocks the red reflex, significantly reducing visibility of the anterior capsulotomy during surgery.
| Item | Intumescent cataract | Hypermature Morgagnian cataract |
|---|---|---|
| Anterior cortical striae | Fan-shaped striae present | None |
| Nucleus state | Solid or softened | Liquefaction and sinking to the bottom |
| Capsule state | Bulging and tension | Thinning |
| Red reflex | Absent | Absent |
AS-OCT allows non-invasive evaluation of lens thickness, sphericity, and fluid accumulation sites. It helps identify areas at high risk of radial extension of the anterior capsulotomy during surgery, aiding in planning the capsulotomy start position and technique. It is also useful for objectively classifying the degree of lens swelling before surgery.
The main risk factors for intumescent cataract are listed below.
Weakness of the zonules (common in elderly patients and those with traumatic cataracts) increases the difficulty of intraoperative IOL fixation.
Diagnosis is based on slit-lamp microscopy combined with imaging tests.
Perform a complete preoperative examination and IOL power calculation. Intravenous mannitol administration to lower intraocular pressure and reduce the pressure difference between the anterior capsule and the capsular bag is effective 1).
Standard cataract surgery (phacoemulsification) is the basis, with the following modifications.
Intraoperative Special Techniques
Vacuum rhexis: A technique using a 24-gauge needle and a 10 mL syringe for aspiration. It has been reported as an alternative for cases where continuous curvilinear capsulorhexis is difficult.
Two-stage continuous curvilinear capsulorhexis: A method where a small capsulorhexis is created first, then enlarged after decompression. This prevents sudden extension under high intraocular pressure.
Intraoperative OCT guidance: Perform capsulotomy while monitoring fluid accumulation sites in real time. Avoid areas of elevated intraocular pressure (high risk of radial tears) to proceed with the procedure.
Capsule Protection Techniques
Creation of artificial epinucleus: During phacoemulsification, inject a dispersive OVD behind the nucleus to protect the posterior capsule. In intumescent cataracts, a protective epinucleus is often absent.
Capsular tension ring (CTR): Insert when zonular weakness is suspected and the anterior and posterior capsules are intact. In cases of severe zonular loss, use a sutured CTR.
Alternative IOL fixation: If the capsule or ciliary sulcus is unavailable, choose scleral-fixated IOL or anterior chamber IOL.
In intumescent cataract, dysfunction of the sodium-potassium (Na-K) pump in lens epithelial cells plays a central role.
Dysfunction of the Na-K pump disrupts electrolyte and water balance, leading to inward osmotic pressure and swelling of epithelial cells, which results in cell lysis and cataract formation.
Transmission electron microscopy reveals the following: epithelial swelling, intracellular vacuolization, release of osmotic granules from lens epithelial cell membranes, and longitudinal breaks in the lens capsule. These changes reduce the tensile strength of the capsule, increasing the risk of complications during surgery.
In traumatic cases, intraocular hydrodynamic energy dissipates the traumatic energy, causing capsular rupture and immediate or delayed opacification.
Patients with intumescent cataracts are prone to the following complications:
In young patients, the lens nucleus softens and the cortex becomes opaque, while the capsule tends to overstretch, becoming highly mobile and prone to rupture. Ultrasound energy requirements are low, and hydrodissection or hydrodelineation may be unnecessary. In elderly patients, the nucleus tends to enlarge and harden, with a higher risk of zonular weakness.
Early surgery is recommended if secondary complications such as glaucoma or uveitis occur. Without complications, urgency is low, but high intralenticular pressure carries a risk of spontaneous capsular rupture, so surgery at an appropriate time in a specialized facility is advisable.
Research is progressing on a technique that uses intraoperative real-time OCT to identify fluid pockets while performing anterior capsulotomy. By avoiding areas with particularly high intralenticular pressure when initiating the capsulotomy, it is expected to reduce the risk of the Argentine flag sign.
The two-staged CCC, which creates a small capsulotomy initially and enlarges it after decompression, is attracting attention as a technique to prevent sudden anterior capsule tears under high intralenticular pressure. Standardization, including incorporation into surgeon education and training, is a future challenge.
Research is underway on a model that uses AS-OCT data on lens shape and thickness to quantitatively estimate intralenticular pressure preoperatively. Its application to preoperative risk assessment is expected.
