Cover Focus | Mar/Apr '17

Lenticular Coloboma

Lenticular coloboma is often associated with some form of cataract, either posterior cortical or nuclear. Nuclear cataracts are usually nonprogressive, and affected individuals often maintain vision. When the cataracts are more extensive and involve the cortex, they often progress, impair vision, and may warrant phacoemulsification.

Phacoemulsification of a lens with extensive coloboma can be challenging, as vitreous prolapse into the anterior chamber often develops through the coloboma, and elevated anterior vitreous pressure—due to swelling of the vitreous body—may be encountered.

This video presents a lens coloboma for which phacoemulsification was planned. On beginning, the first few steps were uneventful, and a continuous curvilinear capsulorhexis was completely successfully. Hydrodissection was done, and phacoemulsification commenced.

TIP

Phacoemulsification of a lens with extensive coloboma can be challenging, as vitreous prolapse into the anterior chamber often develops through the coloboma and elevated
anterior vitreous pressure may be encountered.

A sudden up-thrust faced during phacoemulsification caused a shallowing of the anterior chamber and made maneuvering difficult. This was denoted in the way injected viscoelastic kept prolapsing out. This was attributed to the hydration by saline irrigation and consequent swelling of the vitreous body via the communication between the anterior and posterior chambers.

OUR PROPOSAL

Our proposal in these situations is to place a pars plana trocar away from the coloboma site, allowing us to perform a dry vitrectomy whenever aqueous misdirection is seen. Intermittent vitrectomy with a moderate cutting rate and low vacuum parameters accompanied with the temporary halting of phacoemulsification prevents vitreous herniation into the anterior chamber, reduces intravitreal swelling, and limits the extension of zonular compromise, thereby facilitating safe phacoemulsification.

In this case, phacoemulsification was completed without a struggle, following dry vitrectomy, which was done intermittently as required.

Epinuclear fragments were removed, and complete cortical aspiration was performed. A three-piece IOL was implanted and found to be stable. Repair of the iris coloboma was done by pupilloplasty, yielding a regular, round pupil.

On postoperative day 1, a clear cornea, a round pupil, and a stable IOL were noted, enabling the patient to enjoy good vision.

author
Ashvin Agarwal, MD

NEXT IN THIS ISSUE