Visual outcomes of cataract surgery in glaucomatous eyes hinge on IOL choice

The patient’s age and level of disease should be taken into consideration.

As cataract surgery is embraced as a go-to treatment for select patients with controlled glaucoma, IOL selection plays a vital role in optimizing outcomes and minimizing complications.

Richard A. Lewis

Phacoemulsification alone benefits many glaucoma patients, according to Richard A. Lewis, MD, in an interview.

“Cataract surgery is often the preferred glaucoma procedure,” Steven D. Vold, MD, added, particularly in angle-closure glaucoma. “We probably have a 99% success rate in improving patient vision. [Patients] see better, get improved IOP outcomes and, depending on which lens is chosen, can potentially reduce their dependence on glasses postoperatively.”

For example, the aspheric AcrySof IQ ReStor IOL with a +3 D addition (Alcon) benefits patients with ocular hypertension or controlled glaucoma and no appreciable visual field loss, he said. The Crystalens accommodating IOL (Bausch + Lomb) is beneficial for patients with suspected glaucoma, ocular hypertension or mild glaucoma. The Tecnis multifocal IOL (Abbott Medical Optics) is suited for glaucoma suspects and early glaucoma.

Dr. Vold said that the IOP-lowering effect of cataract surgery is most significant in patients with higher baseline IOP.

“If they have higher pressures and early to no damage of the optic nerve, cataract surgery is a fantastic treatment,” Dr. Vold said, adding that patients with moderate to advanced disease can also sometimes achieve outstanding outcomes.

However, cataract surgery usually offers only a short-term reduction in IOP, typically 6 to 12 months, Y. Ralph Chu, MD, told PCON.

“The cataract surgery will reduce the pressure temporarily, and we can watch it after surgery, depending on how severe the glaucoma is,” he said.

Using multifocal IOLs

Patients with early glaucoma and controlled ocular hypertension who do not have appreciable visual field loss may benefit from multifocal IOLs. However, multifocal lenses diminish contrast sensitivity and may not be appropriate for some glaucoma patients, Dr. Vold said.

“Instead of enhancing [the patient’s] vision, you potentially could give them a lesser quality of vision,” Dr. Vold said.

Dr. Vold uses the AcrySof ReStor multifocal IOL with a 3 D add in patients with stable, well-controlled glaucoma and no significant visual field defects who are less at risk for more progressive loss.

Conversely, significant visual field loss offsets improvements in visual quality offered by multifocal IOLs, Dr. Vold said. Even in moderate glaucoma, he worries about development of advanced disease, he said.

Thomas W. Samuelson

Thomas W. Samuelson, MD, Glaucoma Section Editor for Ocular Surgery News, sister publication of Primary Care Optometry News, is also cautious when considering multifocal IOLs in glaucomatous eyes with significant visual field loss.

“I am reluctant to use the currently available multifocal implants in the setting of moderate or worse glaucoma,” he said. “That is not to say that select patients could not do well with them, but it is hard to predict which ones will.”

Accommodating lenses

Patient selection is critical in cases involving presbyopia correction, Dr. Samuelson said.

“I tend not to use presbyopia-correcting implants in patients with significant visual field loss,” he said.

However, accommodating IOLs are “a little more forgiving” and can improve vision in eyes with controlled glaucoma, Dr. Samuelson said.

While preserving contrast sensitivity, current accommodating IOL designs often yield less near vision than multifocal lenses, he added. Current multifocal designs split light into distance and near, resulting in better near vision but also potentially reducing contrast sensitivity.

“[Accommodating lenses] more uniformly maintain all the visual input without splitting [light] and just shift the focus,” Dr. Samuelson said. “Unfortunately, in my experience, they do not give as much near vision as the multifocals.”

The Crystalens aspheric accommodating IOL improves vision for patients with mild and moderate glaucoma, Dr. Vold said, but implanting these lenses in severely glaucomatous eyes is counterproductive.

However, he said he would not hesitate to use that lens in patients with suspected glaucoma, ocular hypertension or mild glaucoma, but not in advanced glaucoma.

As with accommodating IOLs in general, the Crystalens preserves contrast sensitivity but does not offer near vision comparable to that of multifocal lenses, Dr. Vold said.

“The ideal lens in glaucoma patients, probably, is an accommodative IOL,” he said. “The problem is that it does not give you quite as good near vision unless you do kind of a mini-monovision, where you set a nondominant eye for a little bit intermediate to near, then the distance with the dominant eye. They just don’t have quite the range.”

Improvements in accommodation

Dr. Samuelson said an accommodating lens that optimizes near and distance vision would be ideal for all patients, not just those with contrast sensitivity issues.

“An implant that uniformly focuses all the light on a single focal point that changes from distance to near would be fantastic,” he said.

The Synchrony dual-optic accommodating IOL (Visiogen) may benefit some glaucoma patients.

“It may help with pressure reduction because of the accommodation. It could be very useful in glaucoma,” Dr. Lewis said.

The Tetraflex accommodating IOL (Lenstec), currently undergoing U.S. Food and Drug Administration review, offers up to 2 D of accommodation and is a potentially reasonable lens to use in glaucoma patients, Dr. Vold said.

Toric IOLs show promise

The ReStor toric multifocal IOL, which is also under review by the FDA, may signify an advance in IOL technology, Dr. Vold said.

“I would not be surprised if that becomes one of the real leaders of the pack of the presbyopic IOLs,” he said.

Toric IOLs are a “win-win” for most glaucoma patients and may be underused, Dr. Vold said.

They are particularly suited to glaucoma patients who undergo cataract surgery after filtration or tube shunt surgery. Toric IOLs are also appropriate for glaucoma patients who have combined cataract surgery and minimally invasive glaucoma procedures such as the Trabectome (NeoMedix), canaloplasty (iScience Interventional), or insertion of the iStent (Glaukos) or CyPass (Transcend Medical).

“Toric IOLs are beneficial to glaucoma patients with astigmatism undergoing cataract surgery alone,” Dr. Vold said. “My impression is that toric IOLs are underutilized in each of these situations by many surgeons.”

Toric IOLs are good for glaucoma patients because they do not diminish contrast sensitivity, Dr. Samuelson said.

“The toric IOL really has very little downside because it is not splitting light and it is not reducing contrast sensitivity,” Dr. Samuelson said. “I am excited about the implant designs that have recently become available and that we expect to become available.”

Toric IOLs are also ideal for glaucoma patients because they correct induced astigmatism associated with glaucoma surgery. Astigmatism is a common sequela of glaucoma surgery, but once the astigmatism is stable, “correcting that with a toric is great,” Dr. Lewis said.

Phakic IOLs

Dr. Chu said he is reluctant to implant phakic IOLs in glaucomatous eyes based on anatomic considerations.

“If you are putting a prosthetic in the eye, there is a risk with posterior chamber lenses of pupillary block, pigment dispersion,” Dr. Chu said. “The ocular anatomy assessment is critical. Right now, even in the anterior chamber, whether it is an iris fix, especially an angle fix, you have to be careful in patients with glaucoma.”

Relatively young patients with pre-existing glaucoma or other ocular conditions are not good candidates for phakic IOL implantation, Dr. Chu said.

“Phakic IOL patients in my practice are usually in their 30s,” he said. “If they are having signs of glaucoma or ocular health issues in their 30s, they have a long way to go with their eyes, so I’m very reluctant to offer any sort of phakic IOL technology in that situation.”

Perioperative treatment

Maynard L. Pohl

Perioperative glaucoma treatment requires constant, meticulous monitoring of IOP and medications, Maynard L. Pohl, OD, told PCON in an interview.

“I routinely do not stop antiglaucoma medications perioperatively, unless a miotic has been used, which is uncommon,” Dr. Pohl said. “I continue all non-miotic antiglaucoma drops, including the prostaglandins, throughout the perioperative period as they were administered previously and emphasize compliance. In fact, at the time of cataract surgery all of our patients (including those without glaucoma) are given one 250-mg acetazolamide tablet preoperatively, unless systemically contraindicated, to enable IOP control.”

Dr. Pohl said he advises patients on long-term miotic therapy to discontinue the drop 24 hours before surgery.

Overall, Dr. Pohl’s postoperative drug regimen is essentially the same for glaucoma and nonglaucoma patients unless postoperative IOP as measured by Goldmann applanation is higher than the target value 1 day postoperatively.

“In that case, I would add antiglaucoma medicines, such as adding a topical aqueous suppressant that is not already being used,” Dr. Pohl said. “The additional management depends on the severity of the postoperative elevation of the IOP. Occasionally, the IOP can be positively lowered in a glaucoma patient following cataract surgery, although careful ongoing glaucoma monitoring after any changes in medical management is essential.” – by Matt Hasson

• Y. Ralph Chu, MD, can be reached at Chu Vision Institute, 9117 Lyndale Ave. South, Bloomington, MN 55420; (952) 835-0965; yrchu@chuvision.com.
• Richard A. Lewis, MD, can be reached at 1515 River Park Drive, Sacramento, CA 95815; (916) 649-1515; rlewiseyemd@yahoo.com.
• Maynard L. Pohl, OD, can be reached at Pacific Cataract & Laser Institute, 10500 NE 8th St., Ste. 1650, Bellevue, WA 98004; (800) 926-3007; maynard.pohl@pcli.com.
• Thomas W. Samuelson, MD, can be reached at Minnesota Eye Consultants, 701 E. 24th St., Suite 100, Minneapolis, MN 55404; (612) 813-3628; twsamuelson@mneye.com.
• Steven D. Vold, MD, can be reached at Boozman-Hof Regional Eye Clinic, 3737 West Walnut, Rogers, AR 72756; (479) 246-1700; svold@cox.net.
• Disclosures: Dr. Chu is a consultant to Abbott Medical Optics and Bausch + Lomb. Dr. Lewis is an investigator for the Visiogen clinical trial. Dr. Pohl has no direct financial interest in any of the products mentioned in this article nor is he a paid consultant for any companies mentioned. Dr. Samuelson is a consultant for Alcon, Abbott Medical Optics, Glaukos and iScience. Dr. Vold is a consultant for Alcon, NeoMedix, iScience Interventional, Glaukos and Transcend Medical.