Stephen S. Lane

Phacoemulsification of the extremely dense cataract poses challenges for even the most experienced cataract surgeon. The absence of a protective epinuclear layer, the paucity of cortex, the fragility of the capsule, and the potential laxity of zonules all increase the risk to the supportive structures of the lens during surgery. Most often, longer phaco times at higher energy levels increase not only the risk of corneal endothelial damage, but also the risks of mechanical or thermal injury to the iris or corneal incision. Successful surgical management of these cases requires planning and careful attention to detail. Although these patients are at a higher risk for complications, they are among the most grateful for the treatment because they go from legally blind back to normal vision, assuming the retina is normal, and are usually able to resume their normal activities of daily living. This chapter addresses some of the specific considerations presented by the rock-hard cataract, characterized by a darkly brunescent nucleus with the color of a cola soft drink.

Preoperative Examination

Patients with dense brunescent cataracts often present with a long-standing history of markedly decreased vision that has slowly deteriorated over the years. These patients typically have visual acuities worse than 20/200, and both eyes tend to be affected relatively equally. The patients are often older and may have coexisting ocular pathology or conditions that can affect the final visual outcome. Unilateral brunescent cataracts with minimal to no cataract in the opposite eye should alert the surgeon to the potential of previous trauma in the cataractous eye.

A careful slit-lamp microscopy examination can detect corneal endothelial compromise, a shallow anterior chamber, and signs of lens zonular laxity. The density and opacity of the nucleus may preclude a clear view of the posterior segment of the eye, and an ultrasonic examination may be required to rule out a retinal detachment or choroidal tumor. Patients with very dense cataracts often have not received medical eye care for years, and there can be occult comorbidities, such as glaucoma, macular degeneration, or retinal disease; as best as these comorbidities can be visualized, attempts should be made to determine the status of the retina.

Biometry can be a challenge as well because optical methods of axial length determination may not be able to penetrate the dense cataract. Similarly, the patient may have trouble fixating on a target during keratometry evaluation. Because of the severe visual deficit, these patients tend to be very forgiving of any residual refractive error, and we can further enhance useful vision by leaning toward a myopic result should there be any issues with lens calculations.

The following section describes the step-by-step management of the challenges presented by these cases.

Intraoperative Techniques and Considerations

Consider a Scleral Incision

The phacoemulsification primary incision can be made in either the sclera or the cornea. Wound construction and location are critical as there is an increased risk of corneal incisional burns as the result of higher amounts of ultrasound energy used in removing a dense cataract. A clear corneal incision most often enables the balanced salt solution to keep the incision cooled. However, a scleral tunnel incision has the benefit of potential enlargement should the surgeon wish to convert to a manual extraction method. The advantages of starting with a scleral incision is that if the surgeon should encounter a nucleus that is simply too dense to be emulsified or if the procedure is proceeding poorly, a larger incision is much more easily accomplished from a scleral approach than if the incision was purely clear corneal.

Enhanced Visualization of the Capsule