February 2017

 

COVER FEATURE

 

Glaucoma and the cataract patient
Managing glaucoma medication after cataract surgery


by Liz Hillman EyeWorld Staff Writer

 
   

“Evidence connecting use of prostaglandin analogues before and after cataract extraction with increased risk of cystoid macular edema is insufficient to judge the relative risk of withdrawing prostaglandins
versus continuing them.”
–Scott Fudemberg, MD

Balancing possible risks while maintaining safe IOP control

For a glaucoma patient, cataract surgery alone can have an IOP-lowering effect, though perhaps short lived. So when is it safe to reduce a patient’s glaucoma medications? Is there an optimal paradigm for managing glaucoma medication post-cataract surgery?
Several studies have associated prostaglandin analogues—often the first line of treatment for IOP lowering—with the possibility of cystoid macular edema (CME).1,2,3 Couple that with cataract surgery, which itself carries a risk for macular edema, and “the risk factors start adding up,” said Parag Parekh, MD, Clearview Eye Consultants, State College, Pennsylvania.
Despite these theoretical risks, Dr. Parekh, Scott Fudemberg, MD, Wills Eye Hospital, Philadelphia, and Husam Ansari, MD, PhD, Ophthalmic Consultants of Boston, said they are comfortable leaving most glaucoma patients on prostaglandin analogues after cataract surgery while they’re also on a steroid regimen.
“Evidence connecting use of prostaglandin analogues before and after cataract extraction with increased risk of cystoid macular edema is insufficient to judge the relative risk of withdrawing prostaglandins versus continuing them,” Dr. Fudemberg said. “Therefore, if I perceive the risk of complications from IOP elevation without a prostaglandin to be low, I will stop the medication on the day of surgery and evaluate the patient’s need for IOP lowering agents during the postoperative period.”
Dr. Ansari doesn’t think the risk for inflammation or CME is high enough to stop prostaglandins when the patient’s glaucoma control is critical, especially because he uses a strong steroid to reduce inflammation. Dr. Parekh said that while he knows of ophthalmologists who stop prostaglandin medications, he doesn’t find continuing them to be an issue and has his patients stick with these drops during the perioperative period.
A survey sent to consultant ophthalmologists in the U.K. in 2003 revealed that of the 519 who responded, 59.7% did not stop prostaglandins with cataract surgery, 20.8% stopped if there were other risk factors for CME, and 19.5% routinely stopped.4 Most resumed prostaglandin analogues 30 to 60 days postop.
There are some patients, however, in which the physicians interviewed for this article said they would discontinue prostaglandins. Patients with diabetic retinopathy, retinal vascular occlusion, and epiretinal membrane, for example, are at risk for CME without surgery, Dr. Fudemberg said, noting that they are, however, less likely to be on a prostaglandin anyway. Surgical complications, such as posterior capsule rupture, could prompt withdrawal of a prostaglandin analogue postop as well, he added.
Dr. Ansari said he routinely stops prostaglandins—and other glaucoma drops for that matter—in patients who have been taking them for ocular hypertension.
“In many patients with ocular hypertension, we treat them with eye pressure lowering drops to reduce the risk of them developing glaucoma in the future and when those patients are presenting to me for cataract surgery. I do often stop their glaucoma drops immediately after cataract surgery because I see their pressure becomes quite good after the cataract is removed, and they no longer need the glaucoma drop to lower their eye pressure,” he said.
Dr. Parekh said he might consider taking ocular hypertension patients being treated prophylactically with prostaglandins off these drops after steroids used post-cataract surgery have washed out to reveal the new pseudophakic baseline IOP where their pressure levels out.
If there is concern for CME while continuing a prostaglandin post-cataract surgery, Dr. Parekh advised watching the macula closely with a slit lamp examination and also with OCT imaging.
As for other glaucoma medications post-cataract surgery, Dr. Parekh said he generally would continue patients with what they were on prior to surgery. Drs. Ansari and Fudemberg said altering other drop regimens would depend on the patient’s glaucoma status.
“If the patient happens to be on pilocarpine, I am comfortable stopping that after cataract surgery, but not too many patients are on pilocarpine,” Dr. Ansari said. “When it comes to stopping other glaucoma drops, it depends on the status of their glaucoma. I typically don’t stop glaucoma drops if the patient has glaucoma. If the patient has ocular hypertension, I routinely stop glaucoma drops and monitor the pressure and add back the glaucoma drops if I see the pressure going up again in the weeks or months after surgery.”
“I do not routinely stop glaucoma medications after cataract extraction in the early postoperative period, with the exception of prostaglandin analogues in some cases,” Dr. Fudemberg said. “Perhaps as a result of selection bias in my tertiary referral glaucoma patients, I am sensitive to the risk of postoperative IOP spikes. However, in patients with good IOP control beyond the early postoperative period, I will consider a systematic withdrawal of glaucoma medications in which patients hold a glaucoma medication for a few days prior to their next scheduled visit with me so significant IOP spikes are quickly identified.”
Dr. Fudemberg added that he’s open to the use of any glaucoma medication following cataract extraction, thinking that the side effects of these medications need to be balanced with each patient’s clinical situation.
“Ideally, I prefer aqueous suppression. Beta blockers have a good topical side effect profile, but may be contraindicated systemically. Carbonic anhydrase inhibitors are usually well tolerated, but could challenge the corneal endothelium, and stinging may be a problem in an eye sensitized by surgery. Alpha agonists are also a good choice, but intolerance reaction risks provoking eye rubbing in some patients,” Dr. Fudemberg said. “I am more liberal with combination agents in the postoperative period to help gain control of an IOP spike and simplify a drop regimen already complicated by postoperative medications like steroids, antibiotics, and NSAIDs.”
As for his steroid regimen, Dr. Fudemberg said he doesn’t alter his usual treatment or taper in glaucoma patients without prior filtering surgery. Patients who have had filtering surgery, however, could benefit from more aggressive steroid therapy because inflammation could interfere with the function of a trabeculectomy or tube shunt surgery.
“However, no evidence-based regimen of steroid use following filtering surgery or after cataract surgery in patients with prior filtering surgery has been established,” Dr. Fudemberg added.
Dr. Parekh said his steroid regimen—topical drops four times a day for a month, stopping without a taper—is not altered for glaucoma patients, but he does watch them more closely during postop visits. Dr. Ansari also does not vary his steroid regimen—Durezol (difluprednate, Alcon, Fort Worth, Texas) for 3 weeks with a three-drop, two-drop, one-drop taper—among glaucoma and non-glaucoma patients.
The increase in dropless antibiotic and steroid options, as well as combined options for fewer drops, could impact postoperative glaucoma medication regimens, Dr. Parekh said.
“With the new ‘dropless’ regimens, I think there is a higher rate of breakthrough inflammation requiring ‘rescue,’ compared to the traditional topical regimens,” Dr. Parekh said. “Based on this, I would deduce that the topical regimen has more anti-inflammatory power than the dropless regimen … because you have a lot more breakthrough in one situation than you do in the other. Therefore, I would be more nervous if I was going to do the ‘dropless’ intravitreal injection and the patient was on a prostaglandin. I would watch those patients extra carefully or do something additional on those patients.”
That “something additional” could include using a low-dose, topical anti-inflammatory regimen to supplement the intravitreal ‘dropless’ formulation, which Dr. Parekh said could result in less breakthrough and less need for rescue. In this case, he would then recommend leaving the previous prostaglandin treatment alone.
“It’s a new idea so people are going to experiment with it and see what works, see what makes the most sense,” Dr. Parekh said.
Cataract surgery combined with a microinvasive glaucoma surgery (MIGS) is another case where glaucoma drop treatments might be altered —in fact, that’s often the point of a MIGS procedure.
In MIGS cases, Dr. Parekh follows the same postop regimen, letting the steroid wash out afterward, followed by taking the patient off prostaglandins or other glaucoma drops in a step-wise fashion. Dr.
Ansari said after a goniotomy or iStent (Glaukos, San Clemente,
California) coupled with cataract surgery, he will keep patients on their original glaucoma drops and will assess their pressure 1 week postop. If their pressure is low, he will cut back on the drops, reevaluating the pressure again at 1 month postop.
“Anecdotally, about half of my patients seem to derive some benefit from the MIGS procedure. When I say benefit, I mean that they are on the same number of eye drops but with a lower pressure than they were before surgery or they’re on fewer eye drops with the same or better pressure than before surgery,” Dr. Ansari said.
Dr. Ansari hasn’t observed any difference in IOP spikes after MIGS procedures compared with typical cataract surgery.
Another consideration for glaucoma patients in cataract surgery, Dr. Ansari offered, is to pay close attention to the ocular surface.
“Chronic use of glaucoma drops can lead to chronic dry eye and chronic ocular surface disease,” Dr. Ansari said, reinforcing how many know such conditions can skew measurements for IOL power calculations. “As glaucoma specialists who do a lot of cataract surgery or cataract surgeons who take care of a lot of glaucoma patients, we have to pay extra attention to the ocular surface and make sure we are taking steps to optimize the ocular surface of a patient on glaucoma drops before we do their cataract surgery. If you think you’re going to be discontinuing a patient’s glaucoma drop after cataract surgery, you might consider discontinuing it immediately before cataract surgery to help optimize the ocular surface, if you think it’s safe for their glaucoma.”

References

1. Ayyala RS, et al. Cystoid macular edema associated with latanoprost in aphakic and pseudophakic eyes. Am J Ophthalmol. 1998;126:602–4.
2. Lima MC, et al. Visually significant cystoid macular edema in pseudophakic and aphakic patients with glaucoma receiving latanoprost. J Glaucoma. 2000;9:317–21.
3. Wand M, et al. Latanoprost and cystoid macular edema in high-risk aphakic or pseudophakic eyes. J Cataract Refract Surg. 2001;27:1397–1401.
4. Ahad MA, et al. Stopping prostaglandin analogues in uneventful cataract surgery. J Cataract Refract Surg. 2004;30:2644–2645.

Editors’ note: Dr. Parekh has financial interests with Glaukos. Dr. Fudemberg has financial interests with Alcon, Allergan (Dublin, Ireland), Aerie Pharmaceuticals (Irvine, California), and Inotek Pharmaceuticals (Lexington, Massachusetts). Dr. Ansari has financial interests with Ivantis (Irvine, California).

Contact information

Ansari
: hansari@eyeboston.com
Fudemberg: sjf003@gmail.com
Parekh: parag2020@gmail.com

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