Cataract surgery in patients with small pupils is a challenging situation because of the increased risk of complications (i.e., iris trauma, anterior capsular tear, posterior capsular rupture and vitreous loss). Here are suggestions for managing this condition to reduce the risk of these complications:
- Be prepared: know what to expect prior to surgery. Ask if the patient has a history of taking alpha-1 blocker medications, always evaluate the level of pupillary dilation preoperatively, and note the presence of any ocular pathology that can interfere with good dilation such as pseudoexfoliation syndrome and posterior synechiae.
- Choose the appropriate tool to achieve adequate intraoperative pupil size: the approach to managing a small pupil depends on the underlying condition causing the poor dilation. Patients with a mechanical obstruction to dilation (i.e., posterior synechiae, fibrosis of the pupillary margin, pseudoexfoliation syndrome) can easily be treated by lysing adhesions, removing any fibrotic membrane, and stretching the pupil in several directions with microhooks. Often stronger dilating drugs such as phenylephrine 10% or intracameral epinephrine are effective as well.
On the other hand, an atonic pupil usually requires a pupil-expanding device such as iris retractors or rings (i.e., Malyugin ring, Graether 2000 pupil expander system, Morcher pupil dilator), but because of the range of severity of IFIS, mild forms may respond to pharmacologic agents. Alternatively, a viscoadaptive OVD such as Healon 5 is also usually effective at enlarging the pupil to an adequate diameter. I prefer to use the Maylugin ring in all cases of IFIS because it is easy to insert and remove, produces good dilation, stabilizes the iris, and does not distort the pupil or damage the iris. - Adjust your phaco technique: small pupil cases may also require some modifications to surgical technique. Realize that the case may take longer than usual and be patient. The capsulorrhexis is more difficult and may need to be created under the edge of the iris without direct visualization. Hydrodissection must be gentle if Healon 5 is used since capsular block or rupture of the posterior capsule can occur. Visualization of the phaco needle and second instrument during nucleus disassembly may also be limited, so rather than blindly sculpting grooves under the iris with divide-and-conquer or reaching a chopper under the iris with phaco chop, it may be safer to work centrally under direct visualization by prolapsing the nucleus out of the bag or using a vertical/quick chop technique. Cortical removal is also more challenging with the limited visualization caused by a smaller pupil. The I/A tip must be placed under the iris to grasp the cortical material. Similarly, IOL insertion is more difficult and attention must be paid to confirming that both haptics are positioned within the capsular bag.
By knowing how to handle small pupils and being familiar with the various techniques at our disposal, we can approach these cases more confidently and provide more successful outcomes to our patients.