A 65-year-old female presented with left eye redness for 5 days, on a background of long-standing blurred vision. There was no history of ocular trauma. Slit lamp examination revealed a brunescent cataract that had shrunken significantly in size, such that the zonules and lens equator could be seen through the pupil (Figure 1). The intraocular pressure (IOP) was high at 43 mmHg, and there was a significant amount of anterior chamber cells and flare, but no hypopyon or keratic precipitates. There was a grade 3 relative afferent pupillary defect and a poor visual acuity of light perception in the affected eye. There was no view of the fundus, and a B scan that was performed did not show any significant posterior segment pathology (Figure 2).

Figure 1: Slit lamp photograph of a hypermature shrunken cataract.

Figure 2: B scan of posterior segment of affected eye.

An ultrasound biomicroscopy (UBM) showed a shrunken cataract that had dislocated into the anterior chamber from the inferior quadrant and was blocking the pupil (Figure 3). The inferior zonules were lax, while the rest of the zonules appeared to be still attached to the capsular bag.

Figure 3: Ultrasound biomicroscopy of a hypermature shrunken cataract.

After medical therapy with oral acetazolamide and maximal topical intra-ocular lowering medications, the patient’s IOP was lowered to the mid-twenties. She was also given topical prednisolone acetate to reduce the anterior segment inflammation. She subsequently underwent a phacoemulsification and anterior vitrectomy. A guarded visual prognosis was provided to the patient in light of the pre-existing relative afferent pupillary defect.

Post-operatively, her vision improved from perception of light to hand movements. On the first post-operative day, the cornea was clear, and there was no vitreous in the anterior chamber. There was some post-operative anterior segment inflammation initially, which resolved by the second post-operative week with topical steroids and antibiotics. The intraocular pressure was normal on the first post-operative day, but slowly increased over the next few months, requiring the addition of 3 topical IOP-lowering drops. Fundus examination showed a pale disc.

This case highlights a hypermature cataract that is unusual in its presentation in that the liquefied cortex had partly resorbed and partly leaked out of the anterior capsule, and the capsular bag has shrunken over time, leaving behind a shrunken nucleus with complications of lens subluxation and phacolytic glaucoma.

As a cataract matures, the lens fibers degenerate, leaving cytoplasmic protein globules that coalesce to create accumulations of liquefied lens protein. A Morgagnian cataract forms when the lens nucleus is left floating in the liquefied cortex [1].

The molecular weight of the lens proteins also increases as the lens ages, and together with protein-laden macrophages, can leak through microscopic openings in the lens capsule into the anterior chamber. This precipitates an inflammatory reaction and causes obstruction of trabecular outflow, resulting in an open angle inflammatory glaucoma that is termed phacolytic glaucoma. Although the anterior lens capsule appears intact macroscopically in phaolytic glaucoma, disruptions of the anterior lens capsule have been reported on scanning electron microscopy [2].

The definitive treatment for phacolytic glaucoma is cataract extraction. Performing a UBM prior to the surgery would be helpful to identify any pre-morbid ocular complications that may pose risks to the surgery, such as lax zonules in this case. In view of a poor visual potential, the surgical management for this case was to remove the cataract, perform an anterior vitrectomy and to leave the eye aphakic. The potential intraoperative complications of the surgery include nucleus drop into the vitreous, which may require pars plana vitrectomy. This patient did not have any intraoperative complications.