Article

Hitting the Glaucoma/Cataract Bullseye

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WHEN IT COMES TO COMBINED GLAUCOMA AND CATARACT surgery, can we hit two targets at once? Moreover, can we hit the bullseye for both? In archery, this is called a “Robin Hood”—when the first arrow hits the bullseye, and the second arrow splinters the first arrow in half. I’d like to share some uplifting anecdotes and advice that I hope will encourage us to try for the “Robin Hood” in glaucoma/cataract surgery. As with archery, there are dangers to avoid and best practices for safety that we should adopt.

Decades ago, improving vision while addressing glaucoma was impossible. The best we could offer was hope that visual acuity wouldn’t get worse. The typical discussion with the patient went like this: “Welcome. You can’t tell that you have a problem, but I’m telling you that you do, and you’ll have to trust me. The best we can do is only make your vision slightly worse while perhaps addressing this disease that you may or may not even otherwise notice many years down the road.”

This is a pretty gloomy outlook, and even though I’m all for underselling and overdelivering, we are living in an era when we are thankfully able to do more for a patient’s well-being with newer technologies. We’re able to do so thanks to many pioneers in the field who have made, and continue to make, great strides toward hitting refractive and intraocular pressure (IOP) targets with combined surgery.

Expanding Options

These ideas aren’t anything new. Even monovision with monofocal intraocular lenses (IOLs) could be considered “refractive glaucoma cataract surgery.” However, new extended depth of vision technologies have expanded the landscape of treatment options available to glaucoma patients. In their excellent article on the selection of presbyopia-correcting IOLs, De Francesco et al. outline considerations for these IOLs in glaucoma patients1.

Patients with glaucoma are more likely to have refractive surprises with cataract surgery. However, it has also been reported that, if certain minimally invasive glaucoma surgery (MIGS) procedures are done at the time of cataract surgery, it does not further increase their risk of refractive surprise.2

Indeed, there are excellent outlines of refractive options available to glaucoma patients when it comes to presbyopia-correcting IOLs, and we can now decrease spectacle dependence or achieve spectacle freedom for many of these patients safely.

I would like to draw attention to how, when we are operating on these glaucoma patients, removing their cataracts will often help to lower their pressures. However, it is most often a missed opportunity if we do not combine these procedures with modern MIGS. There are more nuances to consider when straddling the refractive/glaucoma surgery line, but achieving success in both is now realistic and very rewarding.

The Complexity of Combined Surgery

The complexity of this type of refractive/glaucoma surgery is not just the sum of the two procedures—there is a delicate interplay that must be respected for best success. Most importantly, the patient must be aware that the goal is more ambitious and that our expectations must be tempered appropriately. I remind my patients that refractive targets are harder to hit in unusual eyes—often these patients are hyperopes with narrow angles and short axial lengths. They may not be good candidates for postoperative LASIK touch-up; moreover, LASIK could make it more difficult to monitor their IOPs given changes in corneal biomechanics.

I usually find myself erring toward combined cataract/MIGS because I obtain better results from goniotomy/canaloplasty when I combine them with phacoemulsification, and if there is a reasonably mature cataract, I remove it. In other words, I emphasize the necessity of the glaucoma procedure first, and I offer the possibility of refractive improvement as an extra. I think this is the most honest approach, and it puts the patient in a good mindset approaching surgery. That said, I am more often than not surprised by how well patients do in terms of IOP lowering and reaching refractive goals.

Considerations in Reaching Goals

Let’s delve into some of the additional things to consider when approaching this “Robin Hood” goal, starting with the iris.

The iris often plays a role in pathogenesis of glaucoma and the optics of the eye. We must consider this fact with our choice of IOL. Even in a primary angle closure suspect (PACS) who has no damage yet, there is an increased risk of complications that could traumatize the iris (whether or not the patient has already undergone a peripheral iridotomy). Although it might be tempting to use a trifocal IOL in a virgin PACS eye, you should consider using a lens that works independently of the pupil size and that is less prone to glare and halos if you’re worried about the pupil.

Another excellent review should remind us of the relative contraindications to consider when implanting multifocal IOLs, and we should consider these as well when considering extended depth of focus (EDOF) lenses—although they are more forgiving than trifocal IOLs. Pupil expansion is often required in glaucomatous eyes, and we must be able to decide whether we can do this with minimal trauma to the pupil sphincter. With shallow anterior chambers, there is often very little room for pupil-expansion rings: these rings can also risk damage to the endothelium if insertion or removal is traumatic.

A well-centered, optimally-sized capsulorhexis is also important for optimum multifocal functionality, and again, a glaucomatous eye with short axial length and a small pupil is not always a good candidate for femtosecond laser. I find that many of my glaucoma patients have smaller palpebral fissures, making docking of femtosecond lasers more difficult. Thankfully, oval suction rings often help me avoid this problem, but again, one must consider the need for good dilation. Femtosecond laser can also cause subconjunctival hemorrhages, which could affect bleb-based surgery3.

On that note, is it irresponsible to combine premium femtosecond laser-assisted cataract surgery (FLACS) and EDOF lenses with bleb-forming procedures? Perhaps it often is, but not always. One must consider all the previous warnings and cautions when doing so. Additionally, the surgeon must be confident that the patient has good potential for success in controlling their IOPs. In these cases, I would not recommend a multifocal IOL. I would also caution against using EDOF lenses in patients with existing tube shunts or with a strong possibility of needing one in the future. Tube shunts and bleb-forming procedures can induce astigmatism, and are usually reserved for more advanced glaucoma or uncontrolled glaucoma.

All of these points should dissuade us from using multifocal IOLs and proceed with caution when using EDOFs. I don’t think these factors should be absolute contraindications to EDOFs—especially if the patient is aware of the risks involved. Would they be comfortable wearing glasses afterward if their EDOF lens doesn’t perform the way they had hoped? In these cases, it is perhaps “worth a try” to shoot for an EDOF in combination with a bleb-forming procedure. In patients who demand better near vision than EDOF lenses can offer, I often have success with mini-monovision with the nondominant eye set for near. (See the recent excellent article by Dr. Elizabeth Yeu on this topic in the June edition of this publication.4)

Avoid Conflict of Interest

We must also remember that there is a built-in conflict of interest when we sell these patients a premium refractive package: we obviously get paid more for a premium refractive surgery. I will remind my patients of this fact by saying something like, “Remember, I get paid more to do it the ‘fancy’ way, so there is some inherent potential bias there.” The last thing I would want to do is jeopardize a patient’s vision for the sake of a profit, and we need to police ourselves to prevent this from happening. I don’t think a “that would never happen to me” attitude is a good idea because it can be a slippery slope. Pushing the boundaries of refractive surgeries in glaucoma patients can be life-changing for patients and very satisfying for surgeons. And we might get carried away even with the best of intentions.

A Success Story

I will share an anecdotal example of one of my favorite success stories. This patient was on multiple drops preoperatively with a less-than-perfect ocular surface due to drops. His glaucoma was mild. He had a combination cataract surgery with EDOF and goniotomy/canaloplasty. The surgery was a success, and the patient was very happy with his distance vision, good intermediate, and surprisingly good near acuity. Although his acuity was not perfect at any of these distances, the patient was thrilled. We were able to stop all of his glaucoma drops and his IOPs remained excellent.

More exciting still was watching his ocular surface improve over the subsequent months. He said, “Doc, this sounds crazy, but my vision still keeps getting better and better.” There was minimal postoperative edema and minimal hyphema or red blood cells/cell, so I felt quite strongly that the continuing improvement was due to the improving ocular surface.

I have had similar experiences with standalone goniotomy/canaloplasty surgeries, so I do believe the effect is real. Preoperatively, I tell standalone goniotomy/canaloplasty patients that the goal is to preserve their vision, not improve it. However, those cases in which I am able to taper off many or all of their drops often yield a significant visual improvement due to decreased ocular surface medicamentosa. I share this story as encouragement—similar results are now achievable and common.

I am also cautioning against getting carried away with the possibility of upcharging glaucoma/cataract patients for the sake of profit, especially without adequate counseling and awareness of the potential pitfalls and biases involved with combination refractive/glaucoma surgery. I know the limits of anecdotes in our scientific/medical discourse, but I am going to include another (the corollary to the aforementioned case) because these extremes do shape my thinking and counseling about this type of surgery. I see them as more common best-case and thankfully less common worst-case scenarios, and I think it’s important for both the patient and the surgeon to be aware of both.

I have seen patients referred for more aggressive glaucoma surgery after MIGS plus multifocal IOLs who were not good candidates for a multifocal IOL at the time of the original surgery due to their advanced glaucoma. I have also had infrequent but frightening cases in which patients’ IOPs spiked dramatically after goniotomy/canaloplasty, and one who suffered visual field loss. All of these are risks I counsel every patient about, but we need to be aware of them as a real possibility. Thankfully, I have only encountered a handful of these worst-case scenarios with phaco/MIGS.

More scientifically rigorous analysis of the distribution of outcomes in these combined cases will continue, and in the meantime we should make sure we leave good margins of safety in our clinical practice.

Moving Forward

I am very grateful to those great surgeon researchers who have pushed the boundaries of what’s possible, and I am only applying what they have discovered and shared with me. I must recognize Dr. Ike Ahmed, who shared his great energy with me during fellowship and taught me so much, and Drs. Carlos Buznego and William Trattler, who ushered me into the world of femtosecond laser and adopted me into their practice. As a young surgeon, I couldn’t bring success and happiness to my patients without great mentorship. If you are testing the waters of combined refractive/glaucoma surgeries, reach out to your local glaucoma specialist. I’m sure you will find them helpful and eager to help you find those potential slam-dunk patients and to avoid disappointments. I wish you all the best in achieving that “Robin Hood” result. ■

References

  1. De Francesco T, Liu J, and Ahmed IK. Presbyopia-Correcting IOL Selection in Patients With Glaucoma: An Update. What factors must be considered when evaluating the evolving lens options for use in glaucomatous eyes? Glaucoma Today July/August 2021 45-47.
  2. Sieck EG, Capitena Young CE, Epstein RS, et al. Refractive outcomes among glaucoma patients undergoing phacoemulsification cataract extraction with and without Kahook Dual Blade goniotomy. Eye Vis. 2019;6:28. https://doi.org/10.1186/s40662-019-0153-2
  3. Braga-Mele R, Chang D, Dewey S, et al; ASCRS Cataract Clinical Committee. Multifocal intraocular lenses: Relative indications and contraindications for implantation. J Cataract Refract Surg. 2014;40(2):313-322.
  4. Yeu E. Modernizing monovision. Presbyopia Physician. 2022;2(2):44-46. https://www.presbyopiaphysician.com/issues/2022/june-2022/modernizing-monovision . Accessed August 16, 2022.