Prevention and treatment of PCO
At Issue posed the following question to a panel of experts: How do you prevent and treat posterior capsule opacification in cataract surgery, and how might new findings change that?
Square-edged IOLs, YAG laser key
Jorge L. Alió
Jorge L. Alió, MD, PhD:
I try to prevent PCO using square-edged IOLs and cleaning the capsular bag as much as possible during the surgery. Even with this, capsular bag cleaning is well-known to have a doubtful effect on PCO, and my most powerful tool is indeed the IOL. I also try to increase the use of corticosteroids during the postoperative period to 6 weeks in order to decrease PCO in cases in which I tried to get the best outcome possible (cases with premium IOLs).
To treat PCO at the moment is impossible. I wait until a significant decrease in the visual function or clear fibrosis is apparent at the slit lamp to perform YAG laser.
The most exciting news about PCO is probably coming from the use of the ARC laser (A.R.C. Laser) during surgery to eliminate the germinal epithelial cells of the equatorial capsular bag. I am involved in this study, and preliminary data is extremely positive.
- Jorge L. Alió, MD, PhD, can be reached at Vissum, Instituto Oftalmologico de Alicante, Avda. de Denia, s/n, 03016 Alicante, Spain; +34-965-150-025; fax: +34-965-151-501; e-mail: email@example.com.
- Disclosure: Dr. Alió is a clinical research investigator for A.R.C. Laser.
Surgery, IOL choice important
Michael Amon, MD:
In principal, there are two ways to reduce PCO formation after cataract surgery. We may influence it with our surgery, with or without drugs, or with our choice of IOL. Surgically, we can create a posterior capsulorrhexis, and we may combine this with a posterior optic capture. This procedure combined with an anterior vitrectomy is the best way to treat congenital cataracts. Because not every case develops PCO and because there is the potential to create some complications, in adults I do not suggest performing a posterior rhexis in cases with a clear capsule. Only in primarily fibrosed capsules or in rural countries without access to YAG treatment does this technique represent a meaningful option.
In general, I prefer to choose an IOL with documented low PCO rates. IOLs with circumferential sharp optic edges and a small haptic-optic junction perform best in this respect. But the IOL material also influences PCO formation. The material with the highest level of capsular biocompatibility seems to be silicone. Hydrophilic acrylics offer other important advantages, such as high uveal biocompatibility, but tend to have slightly higher PCO rates. Definitely the best treatment option for PCO is the YAG laser. Because the complication rates after capsulotomy are low, I think in countries with good access to medical treatment PCO rates are important but should not be the only parameter for optimized IOL selection.
- Michael Amon, MD, can be reached at firstname.lastname@example.org.
- Disclosure: Dr. Amon has no relevant financial disclosures.
PCO is common long-term complication
Alessandro Galan, MD:
PCO still remains the most common long-term complication after cataract surgery. It can be treated by Nd:YAG laser capsulotomy, but this may lead to other complications, so the best option is prevention. This involves modifications in surgical technique, modifications in IOL design (material and geometry), implantation of additional devices and pharmacological therapy.
Regarding the surgical technique, I recommend carefully cleaning the capsular bag at the end of surgery. I always use a Kratz irrigating cannula to remove all the lens residue attached to the posterior capsule. Even if there is no scientific evidence about the beneficial effect, the capsule at the end of surgery looks clean.
It is mandatory to implant the IOL in the bag, with good adhesion between the IOL and posterior capsule. Regarding the IOL material (hydrophilic acrylic, hydrophobic acrylic, silicone), there is no significant difference in PCO development between the different lenses, although hydrophilic IOLs tend to have higher PCO scores and silicone IOLs have lower PCO scores.
The most important contribution to preventing PCO is to use an IOL with a square edge. In particular, I recommend using a 360° square-edged IOL. I do not think that the implantation of a capsular tension ring can reduce the incidence of PCO.
The future is pharmacological therapy with the use of drugs against lens epithelial cells.
- Alessandro Galan, MD, can be reached at Ospedale Civile Sant’Antonio, Via Facciolati 121, Padova, Italy; +39-049-8216780; fax: +39-049-8216541; e-mail: email@example.com.
- Disclosure: Dr. Galan has no relevant financial disclosures.
Progression should be delayed
Boris Malyugin, MD, PhD:
We all know that PCO is the most frequent postoperative complication of cataract surgery. But at the same time, it is relatively easily treatable with the Nd:YAG laser.
With the new generation of IOLs and modern surgical techniques, the rate of PCO decreased significantly. That is why many practicing ophthalmologists do not consider it a major problem today.
At the same time, even the slightest amount of PCO dramatically decreases the performance of multifocal and accommodating IOLs. Keeping in mind the growing popularity of these types of premium lenses, we can state that the interest in preventing PCO in the upcoming years will be growing.
From multiple studies we know that it is not possible to prevent PCO but only more or less successfully delay its progression. The latter is currently done with the meticulous cleaning of the capsular bag from the lens matter and epithelial cells, secure in-the-bag IOL positioning, sizing the anterior capsulorrhexis in order to have an overlay of the optic periphery and using the lenses with the full circumference square-edge optics.
Unfortunately, the idea of epithelial cell removal from the anterior capsule did not prove to be viable in the real clinical world. That is why I personally abandoned this technical step as unnecessary elongation of the surgical procedure.
Currently, different approaches to prevent PCO are under investigation, including osmotic cell lysis and the search for the most suitable chemical agent, antibody or laser energy source.
To the best of my knowledge, one of the latest and most intriguing findings relates to the ability of the capsular bag to stay clear after implantation of the dual-optic IOL in the bag, the latter allowing the capsular bag to stay open and accessible for the intraocular fluids. We will see whether this finding will withstand the test of time.
As soon as the problem of PCO is solved, the path for the real accommodating IOLs will be cleared.
- Boris Malyugin, MD, PhD, can be reached at S. Fyodorov Eye Microsurgery Complex State Institution. He can be reached at Beskudnikovsky Blvd. 59A, Moscow, Russia, 127486; +7-495-488-8511; fax: +7-499-905-8051; e-mail: firstname.lastname@example.org.
- Disclosure: Dr. Malyugin has no relevant financial disclosures.
Surgical alternative could assist
Rupert Menapace, MD:
Sharp edges have significantly improved the barrier function of the optic rim. However, with the popular acrylic optic IOLs, retro-optical pearl formation is only delayed: After 5 years, PCO and YAG rates steadily increased to finally catch up with the poor results of round-edged optics after 8 years. This is due to delayed Soemmering’s ring formation, which progressively re-divides the once-fused capsular and finally annihilates the capsule bend along the posterior optic edge.
Therefore, I have resorted to a surgical alternative that is independent of edge profile and optic material: posterior optic buttonholing. By creating a posterior capsulorrhexis through which the optic of a bag-fixated three-piece lens is buttoned in, centrally migrating lens epithelial cells are deviated to the anterior optic surface. There, exposed to the aqueous, proliferation is limited to the anterior rhexis leaf. Fibrosis is also significantly reduced because direct anterior rhexis leaf to optic contact is prohibited.
With 1,000 such cases being followed for 4 years (minimum 3 years and maximum 6 years), PCO was zero and fibrosis was minimal. No adverse effects, such as inflammation, pressure rise, cystoid macular edema or retinal detachment, were reported in peer-reviewed publications, including investigations with macular high-resolution OCT imaging.
The procedure may be combined with microincision cataract surgery IOLs. With plate-haptic microincision cataract surgery IOLs, sole posterior capsulorrhexis reduces axial opacification.
Editor’s note: Dr. Menapace recommends viewing his contribution to the AAO ONE Podcast, detailing the technique.
- Rupert Menapace, MD, can be reached at Medical University of Vienna, Vienna General Hospital, Department of Ophthalmology, Waehringer Guertel 18-20, A-1090 Vienna, Austria; +43-1-40400-7941; fax: +43-1-40400-6630; e-mail: email@example.com.
- Disclosure: Dr. Menapace has no relevant financial disclosures.