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Managing Coexisting Anterior and Posterior Conditions

Timing is key.

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Increasingly, patients may present in the office of a retinal specialist with multiple conditions, some of which involve the posterior of the eye, such as age-related macular degeneration (AMD), diabetic macular edema (DME), or retinal vein occlusion (RVO), and some of which also involve the anterior of the eye.

There is very little in the way of evidence-based guidelines or consensus on how to best manage these patients, and clinicians have, for the most part, navigated these waters on their own. Retinal Physician surveyed retinal specialists to discover how they chart their course, when it comes to medical therapy, to deliver optimal management when faced with patients who have coexisting conditions.

TIMING CATARACT SURGERY WITH A CO-OCCURRING RETINAL CONDITION

Choosing the best timing for cataract surgery in a patient with a co-occurring retinal condition is a decision of great importance, for it may affect a patient’s long-term vision. Paul Hahn, MD, PhD, a vitreoretinal surgeon, former assistant professor of ophthalmology at Duke University, and an associate at NJ Retina in northern New Jersey, explained that a key objective is to ensure the retina is stable before proceeding with cataract surgery. For patients treated with ongoing anti-VEGF agents, that generally translates to having cataract surgery performed between injections once efficacy has been established and the retina has stabilized. But when patients do not improve with anti-VEGF therapy, other therapies need to be initiated, noted Dr. Hahn.

“The exceptions are people who do not respond to traditional therapies - anti-VEGF agents do not work - and we have to try secondary treatments like steroids,” said Dr. Hahn. “Get them stable and then consider cataract surgery. Another category of patients are those who need cataract surgery urgently.”

Patients whose cataracts are very thick or dense are candidates for immediate surgery, because it is difficult to evaluate the retina and address any pathology involving the retina, explained Dr. Hahn. Performing cataract surgery between a spaced interval of injection treatments for uncomplicated cases is an approach that Dr. Hahn’s counterparts elsewhere in the country have adopted.

“I like to have cataract surgery done 2 weeks after an anti-VEGF injection and 2 weeks before their next injection,” said Michael Patterson, DO, an ophthalmologist at Eye Centers of Tennessee and Captain in the United States Army Reserves.

Worries of cataract surgery potentially aggravating an existing DME are likely to be more heightened compared to worries of cataract surgery worsening AMD or RVO, according to Dr. Patterson.

“My rationale is that if DME gets worse, and you treat it right before surgery and a few weeks after surgery, that gives you good coverage,” said Dr. Patterson. “We know that the peak time for possible worsening of DME is about 6 weeks to 8 weeks out from cataract surgery. If you treat that way, you will not have to worry that much about pretreatment for DME with extra drops.”

Fears about conditions like DME exacerbating with cataract surgery are largely unfounded in contemporary ophthalmology, maintained Pravin Dugel, MD, managing partner at Retinal Consultants of Arizona and Retinal Research Institute LLC in Phoenix, Arizona, and a clinical professor at USC Roski Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, California.

“There was a concern that these retinal conditions may worsen,” said Dr. Dugel. “We used to worry about that a lot. Quite honestly, now that cataract surgery has become so efficient, and as long it is done without producing complications, the chance of a negative effect of cataract surgery on DME is dramatically less.”

CONSIDERATIONS IF VITRECTOMY HAS BEEN PERFORMED

Another variable in overall management of patients with coexisting conditions is whether a patient has undergone a vitrectomy. Eric W. Schneider, MD, a retina specialist and partner at Tennessee Retina, in Nashville, Tennessee, said that he would modify his management of a patient who has undergone vitrectomy and also has glaucoma.

“One option for patients with inadequately controlled glaucoma is to undergo a tube shunt procedure,” said Dr. Schneider. “Traditionally, the tube is placed in the anterior chamber in front of the iris. But in previously vitrectomized patients, the glaucoma specialist has the option to place the tube in the pars plana behind the iris. With this approach, there is less risk of corneal decompensation.” Dr. Schneider underlines that there are also significant differences in previously vitrectomized eyes undergoing cataract surgery.

“Certainly, cataract surgery after vitrectomy is different than cataract surgery in a patient who has not had a vitrectomy,” he explained. “The anterior chamber tends to be deeper and the zonules are looser, and the posterior capsule tends to be floppier, which increases the risk of posterior capsule tear during cataract surgery.”

Cataract surgeons who have familiarity with the impact of vitrectomy are best positioned to work collaboratively with a retina specialist to manage a patient with posterior and anterior pathologies, according to Jennifer I. Lim, MD, FARVO, Marion H. Schenk Chair and Professor of Ophthalmology, Director of the Retina Service, University of Illinois at Chicago.

“Ideally, you would have a cataract surgeon who has experience working with patients who have had a vitrectomy,” said Dr. Lim. “This is because there is no vitreous gel to support the posterior capsule. Some cataract surgeons who have experience with vitrectomy know they need to be more cognizant of the pressure forces and the threat of rupture to the posterior capsule.”

PRETREATING WITH STEROIDS

The efficacy of steroids was evidenced in the Macular Edema: Assessment of Implantable Dexamethasone in Diabetes (MEAD) study, which served as the foundation for the FDA approval of dexamethasone intravitreal implant 0.7 mg (Ozurdex; Allergan) for adults with DME who are scheduled for cataract surgery. Patients who took part in the study, which looked at the impact of a steroid-eluting implant, had a mean duration of DME of 24.9 months before study entry.1

“People who developed a cataract while being treated for DME did remarkably well while Ozurdex was on board,” said Dr. Dugel, the lead investigator of the MEAD study. “My thought is if I had a patient with a cataract and DME, then it is not a bad idea to have Ozurdex on board because those patients did really well in the MEAD study.”

Like Dr. Dugel, Dr. Lim observes that there is a role for a long-acting steroid implant in challenging patients, such as those with chronic edema.

“If patients have chronic edema that is very hard to get under control, sometimes those patients may be better served by a long-acting steroid implant,” said Dr. Lim.

The presence of an epiretinal membrane (ERM) is a clinical challenge if cataract surgery is needed and clinicians have their individual strategies to respond to ERM. “If it is just the ERM without any associated cystic edema, then I do not treat it beforehand with any injections,” noted Dr. Hahn.

Michael Patterson, DO, an ophthalmologist at Eye Centers of Tennessee indicated that there are no data to support the use of anti-VEGF injections to treat ERM, but he does look to steroids, such as triamcinolone acetate, or nonsteroidal anti-inflammatory drops in the presence of ERM, having heightened awareness about the risk of postoperative macula edema. “I also give a stronger pulse of steroids in the posterior pole of the eye,” said Dr. Patterson.

A potential advantage to performing cataract surgery before ERM peel is that the patient’s visual function could improve to the point that ERM surgery isn’t necessary. Cataract surgery can also improve the surgeon’s view for subsequent ERM surgery. But some surgeons may prefer to perform both surgeries together.

“We do combined surgery where we remove the cataract and ERM,” said Dr. Dugel. “It is easier for the patient and easier for me as a vitreoretinal surgeon.”

LEAVING SILICONE OIL IN OR TAKING IT OUT

Clinicians have various approaches to silicone oil, but for the most part, they opt to remove silicone oil or leave it in for no longer than 3 months.

“If you are performing a vitrectomy, and put in silicone oil to repair a retinal detachment, I would leave the oil in from the short end of 6 weeks to on average 3 months, and then remove it,” said Dr. Lim.

Dr. Lim estimated that she leaves the oil in about 10% of cases. “I do not want to deal with pressure elevations that can happen,” said Dr. Lim, warning of the threat of emulsification of oil. “The oil can get into the anterior chamber and plug up the meshwork.”

Some of the instances where Dr. Lim would choose not to remove silicone oil are instances of hypotony where the eye cannot form a good pressure or cases in which the ciliary body is shut down or the eye is so ischemic that it cannot form a pressure. Dr. Hahn said he suspects most retinal specialists would plan to remove silicone oil rather than leave it in.

“When we put oil in, it is for long-term use, but not permanent use,” said Dr. Hahn. “And the plan would be to take it out, but there are some patients with very bad retinal detachments, in whom we plan to leave oil in long-term.” If oil is left in, it is usually removed within a 3- to 6-month period, he said.

An objective with silicone oil is to get it out of the anterior chamber, said Dr. Patterson. “Our normal game plan is to try to avoid letting the oil come in the anterior chamber,” he said. “If it does, we try to remove what comes into the anterior chamber.”

Dr. Schneider highlighted the risk of foveal dysfunction in eyes with good visual potential and prolonged silicone oil tamponade. Though the mechanism of visual loss is unclear, silicone oil has been demonstrated to have a significantly higher rate of unexplained vision loss when used as the tamponade in macula-sparing retinal detachments when compared to gas.2

The duration of tamponade was the only factor related to the incidence of vision loss. “For this reason, I am always careful to remove oil within 3 months of the original surgery in patients with the potential for normal macular function,” noted Dr. Schneider.

HIGH MYOPIA AND RETINAL SCREENING

High myopes are at an elevated risk for retinal detachment, making a retinal examination a judicious step before an intervention like cataract surgery. Dr. Lim recommended myopes (more than 6 dioptres), particularly high myopes (more than 10 dioptres), undergo an exam of the periphery.

“Up to 5% of patients have atrophic holes, and in high myopes, it is obviously higher because they have more peripheral pathology, so I think it is a very good idea for every high myope to get a (retinal) exam,” said Dr. Lim. “If the anterior segment surgeon is confident looking in the periphery, then that is fine. If he or she is not confident and prefers a retinal specialist to do it, a retinal specialist would be happy to do the exam.”

High myopes should be educated about any disturbing symptoms that they may experience post-operatively following cataract surgery. “If they have floaters or are seeing flashing lights, they should come in for an exam after cataract surgery,” said Dr. Lim.

Clinicians should consider factors such as whether a patient has already had a retinal detachment or if there is a family history of retinal detachment with respect to referring a patient for a retinal examination prior to cataract surgery, said Dr. Schneider.

“It depends on the comfort level of the provider,” said Dr. Schneider. “If there is no obvious peripheral pathology and the anterior segment surgeon is confident in their exam, they do not need a separate examination from us (retinal specialists).”

Both Dr. Lim and Dr. Schneider agreed that clinicians should watch for signs of pathology like lattice degeneration in high myopes, for it signifies an increased risk of retinal detachment in these patients. The presence of such findings likely warrants a peripheral exam with a retinal specialist to assure no prophylactic laser therapy is necessary. RP

Editor’s note: This article is featured in a journal club episode of Straight From the Cutter’s Mouth: A Retina Podcast. Listen to the episode at www.retinapodcast.com .

REFERENCES

  1. Boyer DS, Yoon YH, Belfort R Jr, et al; Ozurdex MEAD Study Group. Three-year, randomized, sham-controlled trial of dexamethasone intravitreal implant in patients with diabetic macular edema. Ophthalmology. 2014;121(10):1904-1914.
  2. Scheerlinck LM, Schellekens PA, Liem AT, Steijns D, Leeuwen Rv. Incidence, risk factors, and clinical characteristics of unexplained visual loss after intraocular silicone oil for macula-on retinal detachment. Retina. 2016;36(2):342-350.