BLOG: Prior ocular injury can affect cataract surgery outcomes
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As we all know, the move from intracapsular cataract surgery, where the capsule and the lens are removed together, to extracapsular, where the capsule is left in place to secure the IOL, revolutionized cataract surgery.
Phacoemulsification only improved the patient experience, allowing for a smaller incision, and these changes reduced risk to the retina, decreased (or eliminated) the need for sutures, reduced risk for infection and offered incredible capsular IOL stability. With each advancement, patients’ expectations rose and, in some ways, cataract surgery became the victim of its own success.
Many patients perceive modern cataract surgery as a refractive surgery. One of the most important parts of a cataract evaluation includes assessing and educating patients on their risks, noting any additional ocular disease — especially conditions that affect a patient’s potential acuity or eligibility for specialty lenses like toric or multifocal IOL implants — and moderating patient expectations.
“Under-promise and over-deliver” are words to live by. In this entry, we will explore patient risks for compromised capsules and their impact on patients’ perceived success of their cataract surgery.
A cataract evaluation gives a practitioner minutes to assess a patient’s lifetime of ocular health. It is invaluable when referring providers include a patient’s history of ocular trauma or prior ocular surgery (especially retinal) if known.
At this point I feel like I’ve seen it all: BB gun shot to the eye, bad car accident, bungee cord injury, washing machine door to the orbit, you name it. Patients can be amazed that an event when they were 4 years old is relevant to their cataract extraction (CE) at age 80, so be sure to ask the right questions.
Blunt trauma especially can leave few signs that damage was done to zonular integrity, but knowing the increased likelihood going in allows for preoperative education. If a patient is told their history portends higher risk for intraoperative complications, they are prepared if said complications occur. It is now an unfortunate continuation of their injury and not something the surgeon “did wrong.” But more than this, prior knowledge can allow a surgeon to allot more time for a potential complex case and even plan for a capsular tension ring or partial vitrectomy if needed.
Additional preoperative observations that increase complexity of surgery include a small, poorly dilating pupil, pseudoexfoliation, shallow anterior chamber, floppy iris syndrome and hypermature cataract.
Even in patients without risk factors, damage to the capsular structure — either damage to the capsule or zonules — during surgery can occur with even the most experienced and talented surgeon, with a complication rate of about 2% (Ti et al.). With a thickness of only 5 , it is not difficult to understand that a capsule tear can occur during several stages of CE. This could include radialization of the capsulorrhexis extending to the posterior capsule, an overeager phaco probe vibrating a hole in the capsule, the irrigation and aspiration tip accidentally sucking up a piece of the posterior capsule, during polishing of the posterior capsule, and even during IOL implantation itself. A large enough tear might also see cataract pieces drop into the posterior pole where a retinal specialist will need to retrieve it later.
If poor capsular strength is suspected, or a patient suffers an intraoperative capsular tear, they may not be a candidate for a multifocal IOL where centration is paramount. Toric IOL implantation might be attempted but the surgeon can make the executive decision to switch to a monofocal lens if the capsule cannot provide enough stability or support.
Next month we will explore different surgical technique options for lens implantation with compromised capsules as well as their different risks and benefits.
Reference:
- Ti SE, et al. Am J Ophthalmol. 2014;doi.org/10.1016/j.ajo.2013.08.022.
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