Glaucoma surgeons routinely combine cataract and glaucoma surgeries. In fact, the lens and cataracts are intricately tied to many of the mechanisms that contribute to glaucoma. Although cataract surgeons tend to see these cases as cataract surgery with minimally invasive glaucoma surgeries (MIGS), glaucoma surgeons might see them as glaucoma surgery with cataract removal. Cataract surgeons strive for top refractive outcomes and generally stick to 1 or 2 MIGS procedures, referring more complex cases to their glaucoma-specialist colleagues, whereas glaucoma specialists often stick to standard cataract cases and make glaucoma surgery the main priority.
Today, I try to approach phaco-MIGS cases from both perspectives, doing my best to optimize refractive outcomes at the same level as glaucoma outcomes. In my opinion, glaucoma specialists can do the best job of packaging phaco-MIGS surgery, providing superior, next-level glaucoma care. We can learn a great deal, though, by taking lessons from the best cataract surgeons to improve our refractive outcomes. The results — optimal refractive outcomes and robust pressure control — will be more rewarding for both the patient and the physician.
Minimizing the Refractive Effects of MIGS
With the vast number of MIGS procedures done in combination with cataract surgery, the decision generally comes down to surgeon preference, choosing what feels most comfortable and gets the best outcome. There are, however, a few considerations related to advanced technology intraocular lenses (ATIOLs) and how we can optimize clear vision from day 1.
To limit the impact of MIGS on visual outcomes, we want to minimize bleeding, clefts, and tissue trauma. I often choose canaloplasty followed by goniotomy (trabeculotomy) with the Omni Surgical System (Sight Sciences) for combination surgery because it provides potent, significant, and enduring reduction of IOP to get patients off drops without altering the ocular surface. Omni targets Schlemm’s canal, collector channels, and the trabecular meshwork without leaving hardware outside or inside of the eye, and there’s no bleb to cause astigmatism. I’ve also found that I can tailor goniotomy to be effective for a range of targets.
After a phaco-Omni procedure, my patients are usually able to stop 2 classes of glaucoma drops. In terms of refractive outcomes, patients get that big “wow” with postoperative visual acuity, and I have seen it improve over time as the ocular surface improves without topical glaucoma medications.
In my operating room, the hyphema rate with Omni is below 2% because I find the canaloplasty tamponades the reflux bleeding very well. However, if you haven’t done a lot of Omni, your hyphema rate may be slightly higher until you gain experience. (The average rate reported in studies is about 4%.1-4) Be sure to have a conversation with patients in advance so they know that there’s a risk of hyphema that will affect day-1 vision, but it will clear up within about a week.
Stents such as iStent (Glaukos) and Hydrus (Alcon) are popular choices as well. As glaucoma specialists, we can rely on accurate and atraumatic stent placement, minimizing the impact on vision. Bleb-forming MIGS procedures like Xen (Allergan) can induce astigmatism, but it is possible to use them judiciously in combination surgery (off-label) with appropriate patient counseling.
Choosing Complimentary Techniques and IOLs
MIGS are right in our wheelhouse, but advanced refractive surgery is new to some glaucoma specialists. If you consider what techniques and ATIOLs are appropriate for your glaucoma patients, you’ll find you don’t always need to limit them to standard surgery. Here are some things to keep in mind:
• Dry eye treatment yields accurate measurements. Glaucoma surgeons have a long history of focusing on preventing blindness and pushing dry eye disease off to the side, but to perform on a refractive level equivalent to top refractive surgeons, glaucoma surgeons have to learn from their best practices and treat the ocular surface. (Think of it like optimizing the conjunctiva before bleb surgery.) To evaluate the ocular surface, I do topography, and I thoroughly evaluate the appearance of the tear film and cornea with fluorescein staining. Simple, basic therapies like artificial tears, warm compresses, and blepharitis treatment can get us the measurements we need to achieve the desired outcomes. Newer drops like Meibo (Bausch + Lomb) and therapies for associated conditions like Xdemvy (Tarsus) for demodex show promise in helping to optimize the ocular surface. As with performing gonioscopy and catching primary angle closure suspects, you won’t find dry eye if you don’t look for it.
• Surgical techniques can minimize edema. The vertical chop technique is a modern approach that can minimize edema by reducing energy expenditure during phaco. Although there is quite a big learning curve, I think the vertical chop’s low energy requirement, elegance, and efficiency make it the future of refractive cataract surgery. Femto laser-assisted cataract surgery can also be helpful in expediting nucleus disassembly and reducing phaco energy. Again, if you don’t look for it, you won’t find it: screening for guttata and Fuch’s dystrophy needs to be as habitual for us as it is for cornea/refractive specialists to avoid surprises.
• EDOF and even trifocal lenses can be done with caution. Selecting an IOL requires careful consideration for patients with glaucoma. For example, consider the patient’s dilation because not only will it affect the functionality of trifocal and EDOF lenses, but also pupil expansion during surgery can alter the pupil. Small pupil size, short axial length, and small palpebral fissures also make it difficult to use a femtosecond laser, and the vacuum that the femtosecond laser requires should be avoided in eyes with existing blebs. Because tube shunt surgery induces astigmatism, one needs to use extra caution in these cases as well.
Most importantly, patients need to be stable and have a very low likelihood of progression if we want to entertain the idea of ATIOLs. Remember, diffractive optics divide the available light into different focal points—something that would be problematic for a patient who already suffers from loss of contrast sensitivity. Personally, I err on the side of caution, but every patient is unique and should be offered reasonable options. As an option for patients who want to improve their near vision, I have had success with mini-monovision with near correction in the nondominant eye, especially if a patient has tried monovision in contacts, for example.
• Light-adjustable lenses are a premium option. For patients who ask for advanced, top-of-the-line refractive technologies for cataract surgery, Light Adjustable Lenses (LALs) from RxSight are a promising option because they allow customization of refractive outcomes after surgery in inherently unpredictable eyes. Most glaucoma patients are candidates, even if they have some visual field loss or have had previous refractive surgery. Picking a MIGS that minimizes the chance of bleeding is important with LALs because one needs a clear cornea and anterior chamber to make postoperative adjustments. Of course, LALs also capture additional revenues to help sustain the practice.
As we raise our bar for refractive surgery, patient counseling must follow suit. It’s a nuanced conversation about expectations: refractive targets, optimizing the ocular surface, and what to expect after surgery. We discuss IOLs that are optimal for patients with less-than-ideal visual fields and how we need to maximize the safety margin for success. We also need to be ready to talk about why some patients aren’t candidates for the multifocal IOLs that their friends and neighbors had implanted.
The most important rule that I recommend is to take the conservative approach when in doubt — just because all of these technologies exist doesn’t mean that a simple monofocal IOL is a bad choice. In fact, I tell patients that the simple optics of an aspheric lens is akin to “prime lenses” in photography — they offer great optical quality because of their simplicity. First and foremost, we need to be good stewards of this technology and avoid the temptation to implant a premium lens just for the sake of using the more lucrative option.
Sharing Patients’ Joy and Satisfaction
The reward for careful consideration of all the available options and meticulous preoperative preparation is sharing in patients’ joy. Postoperative day 1 is my favorite day. I wouldn’t give that up for anything. It’s hugely gratifying as glaucoma specialists, because we can get some of the biggest slam-dunk cases in some of the most unlikely scenarios. I’ve reached a new level of patient care by making the decision to optimize refractive outcomes the same way I do glaucoma outcomes, with the bonus of enjoying these satisfying results with my patients. I highly recommend viewing your glaucoma clinic through the lens of a refractive surgeon — you will find it so rewarding to make these patients even happier. GP
References
1. Vold SD, Williamson BK, Hirsch L, et al. Canaloplasty and trabeculotomy with the Omni system in pseudophakic patients with open-angle glaucoma: the ROMEO study. Ophthalmol Glaucoma. 2021;4(2):173-181. doi:10.1016/j.ogla.2020.10.001
2. Hirsch L, Cotliar J, Vold S, et al. Canaloplasty and trabeculotomy ab interno with the Omni system combined with cataract surgery in open-angle glaucoma: 12-month outcomes from the ROMEO study. J Cataract Refract Surg. 2021;47(7):907-915. doi:10.1097/j.jcrs.0000000000000552
3. Terveen DC, Sarkisian SR Jr, Vold SD, et al. Canaloplasty and trabeculotomy with the Omni surgical system in OAG with prior trabecular microbypass stenting. Int Ophthalmol. 2023;43(5):1647-1656. doi:10.1007/s10792-022-02553-6
4. Pyfer MF, Gallardo M, Campbell A, et al. Suppression of diurnal (9am-4pm) IOP fluctuations with minimally invasive glaucoma surgery: an analysis of data from the prospective, multicenter, single-arm GEMINI study. Clin Ophthalmol. 2021;15:3931-3938. doi:10.2147/OPTH.S335486
