#4 of 10: Top Reasons for Poor Premium IOL Outcomes and How to Remedy Them: Managing Posterior Capsular Opacification
Despite the advances in IOL technology, standard or premium; monofocal, accommodating or multifocal; MICS or dual-optic; square-edge or not; posterior capsular opacification still occurs and can be quite menacing to the visual outcome. This is especially true for patients with high expectations for premium IOLs.
Due to the great efforts of Daniele Aron Rosa, MD, the Yag laser became one of the great ophthalmic advances in disruptive technology of posterior capsular opacification.
PCO development typically is multifactorial due to poor cortical clean-up, retained lens epithelial cells (LECs) at the lens equator and/or under the anterior capsule, and/or an irregular non-centered, non-overlapping anterior capsulorrhexis 360° over the IOL optic (Oliver Findl, MD, OSN July 2011).
At the ACOS 2011 summer symposium, Sam Masket, MD, presented reduced PCO rates with particular attention to anterior subcapsular polishing of LECs. The late David Apple, MD had reiterated, despite the popular concept of “no space-no cells” leading to no LECs, that the newer, thinner and more flexible IOLs may not be able to withstand the distortion from posterior capsular shrinkage leading to possible lens decentration. The Z syndrome characteristic of the accommodating Crystalens is a classic example of the latter problem, often necessitating early Yag capsulotomy to avoid induced astigmatism and/or loss of the premium visual outcome.
Prior to capsulotomy, it remains important to perform a good dilated retinal exam often in conjunction with optical coherence tomography (OCT) to ensure the reduced vision is not due to macular pathology, rather than posterior capsular opacification. The toughest challenge, especially with premium IOLs, is the timing for Yag capsulotomy. Obviously if a Z syndrome is present as mentioned above, the sooner the better.
With multifocal IOLs, if a patient complains of glare and/or halos and has residual astigmatism and mild PCO, the approach becomes trickier. If the Yag is done too soon and the patient’s complaints persist despite astigmatism correction, the IOL may have to be removed in the face of an open posterior capsule. On the other hand, refractive error changes, though small, can occur after Yag capsulotomy, and the desire to correct them after the Yag will hopefully limit the number of “enhancements” needed with laser vision correction and/or LRIs to just one time.
My preference in milder PCO is to treat the refractive error first, only if it has stabilized prior to Yag capsulotomy. I find it easier to perform a second refractive enhancement than exchange an IOL with an open posterior capsule in the worst case scenario. In moderate or worse PCO the decision is easier as the PCO typically is the main cause for visual complaint. It is also important to look at angle kappa readings (easily done with the Marco OPD III) prior to capsulotomy, if not measured pre-cataract surgery. In the presence of mild PCO, high angle kappa (typically over 0.4 mm), a multifocal IOL, and complaining patient, I tend to exchange the IOL because Yag capsulotomy treatment won’t solve the multifocal optic confusion. Conversely, with an aspheric toric or aspheric accommodating IOL and high angle kappa, Yag capsulotomy will most likely solve the problem.
The last challenge seen with PCO is whether anti-inflammatory medication is important or not. The intraocular debris from a Yag-disrupted capsulotomy can be inflammatory and potentially migrate to the angle where it can cause a trabeculitiis, and in the worst case cause sudden and/or significant IOP spikes. If a patient is high risk, such as having uveitis history, CME in the fellow eye, or diabetics even without BDR, Cystoid Macular Edema (CME) after Yag capsulotomy becomes a potential additional visual risk, especially in the premium IOL patient. The use of topical steroids such as Lotemax (Bausch & Lomb) with its lower risk of IOP elevation while controlling inflammation and/or a topical nonsteroidal such as Bromday (Ista) with its convenient once-a-day dosing might be good preventive options for the premium IOL patient if a Yag capsulotomy is needed.
In the end, premium IOL patients tend to voice their vision complaints sooner than standard IOL patients if PCO exists, be it a function of the more complex optics of their IOLs or because they have paid a considerable amount for their “advanced” IOL technology. Remember these patients have higher expectations and are more quickly to complain. Stay tuned for managing cystoid macular edema in my next blog in terms of prophylaxis for the premium IOL patient.
Read Part 1, Part 2, or Part 3 of Dr. Jackson’s series.
