Cataract surgery with comorbidities requires careful surgical management

With the incidence of ocular diseases such as age-related macular degeneration, glaucoma and diabetes rising as longevity increases around the world, more patients who require cataract surgery may present with a complex situation.

AMD is the most highly represented comorbidity, accounting for 15% to 19% of cases, whereas glaucoma ranges between 8% and 11%. Diabetic retinopathy is present in approximately 4% of cases, but that number is expected to grow due to the increase of type 2 diabetes worldwide.

“We need to be aware of the unique needs of these special patient populations. There is an impact of comorbidities on the indications, on counseling the patient and on the way to do cataract surgery. This is not just standard cataract,” Rupert Menapace, MD, OSN Europe Edition Editorial Board Member, said.

Rosa Braga-Mele, MD, FRCSC, OSN Cataract Surgery Section Editor, said it is important to assess overall systemic health before designing a treatment plan for patients with AMD, glaucoma or diabetes.

Rupert Menapace, MD, said that patients with cataracts and comorbidities have unique needs. Image courtesy of Menapace R

Dr. Braga-Mele said she takes a multipronged approach to preventing and mitigating AMD in cataract patients, such as vitamin therapy and counseling for patients with drusen and other early signs of the disease.

For patients with AMD or diabetes, monitoring overall health and discussing lifestyle factors such as smoking status and nutrition are critical, Dr. Braga-Mele said.

AMD

Although no rigorous trial has ever proved it, the belief that cataract surgery might increase the risk for development or progression to more advanced stages of AMD may still exist. The Blue Mountains Eye Study and the Beaver Dam Eye Study both listed cataract surgery as a risk factor for AMD, while other more rigorously carried out studies, such as the Age-Related Eye Disease Study, showed that such a correlation does not exist.

Surgeons must choose the appropriate IOL to mitigate, rather than aggravate, visual deficits resulting from AMD, Dr. Braga-Mele said. For example, multifocal IOLs are not recommended for some patients with AMD.

“Depending on the degree of macular degeneration, I would stay away from a multifocal IOL implant because of the fact that contrast sensitivity is decreased with a multifocal implant and contrast sensitivity is already decreased, or will be, with macular degeneration,” she said.

The optimal choice of IOLs for some patients with AMD may be a blue light-filtering IOL that minimizes the risk of damage to the retina, she said.

Rosa Braga-Mele

Dr. Braga-Mele recommended removing advanced cataracts before administering anti-VEGF injections in patients with wet AMD.

“Especially with an advanced cataract, the visibility would be lower for the retina surgeon,” she said. “I think we would be better off taking out the cataract first. Thereby, if posterior capsule perforation did occur, it wouldn’t matter anymore.”

Proceeding with anti-VEGF injections is suitable for patients who have not developed cataracts or have early cataracts, Dr. Braga-Mele said.

Y. Ralph Chu, MD, advocated a comprehensive approach to assessing the cataract patient’s retinal health and postoperative visual potential.

“Generally, we want the eye to be healthy,” Dr. Chu said. “That helps us counsel the patients as to what their visual potential may be. Also, in certain situations, we can even use potential acuity meters. There are various ones on the market. Again, we try to give the patient an idea if it’s worth it to do this cataract.”

Y. Ralph Chu

Cataract patients with mild macular degeneration should receive intense counseling about potential postoperative visual improvement. AMD patients who consider receiving premium IOLs should undergo even more rigorous assessment and counseling, Dr. Chu said.

“If somebody’s thinking about getting a premium IOL, then I think the bar is raised,” he said. “Nothing changes in terms of the standard of care, but the bar is raised in determining whether they should get a premium IOL because these patients are now paying for a result.”

An accommodating IOL is typically more appropriate for a patient with AMD than a multifocal lens because of already diminished contrast sensitivity, Dr. Chu said.

“If I put a premium lens in a patient with mild macular degeneration, it’s typically an accommodating lens because I’m concerned about maximizing their quality of vision,” he said.

Glaucoma

Cataract surgery performed alone or in combination with glaucoma surgery can offer substantial benefits to glaucoma patients. Choosing the right strategy at the right time can be challenging for the surgeon and entails a complex decision-making process.

Factors to be considered are type and stage of glaucoma, previous treatment, IOP level and control, visual field and optic nerve damage and, ultimately, patients’ needs. Based on these factors, there are few cases in which phaco alone may be indicated as a treatment, such as some cases of primary angle-closure glaucoma or early stages of primary open-angle glaucoma with coexisting cataract. Beyond these, the choice widens to a variety of possible combinations in which cataract removal is performed sequentially or at the same time with trabeculectomy, nonpenetrating procedures, laser, and tubes or valve implants.

“It’s a decision process based on if-then rules that we can convert into our personal flow chart or decision tree,” Camille Budo, MD, OSN Europe Edition Editorial Board Member, said.

Camille Budo

Generally speaking, cataract surgery is safe in eyes with glaucoma, but a few problems related with glaucoma pathology may be encountered.

“Eyes with angle-closure glaucoma have very shallow anterior chambers, which create problems with poor maneuverability during capsulorrhexis,” Dr. Budo said.

Patients who have used miotic drugs such as pilocarpine for a long time might have a pupil that does not dilate well. Patients with pseudoexfoliation have weak zonules that increase the chance of a dropped nucleus, he explained.

“As with other comorbidities, we need experienced surgeons. Cataract surgery in glaucomatous eyes is not for beginners,” he said.

When two procedures are needed — one for cataract and one for glaucoma — Dr. Budo likes the combined simultaneous approach.

“One stage and two incisions,” he said.

The two-site approach allows surgeons to perform both procedures in the way they are used to, without modifications and with greater safety.

In phaco-alone or phaco combined with nonpenetrating surgery, Dr. Budo uses a temporal approach for cataract surgery and a superior approach for glaucoma surgery. He prepares the conjunctival and scleral flap in the upper quadrant, leaves them there, performs cataract surgery with IOL implantation in the temporal quadrant, removes the viscoelastic and finally goes back to complete the glaucoma procedure.

“Several studies have shown that results in terms of IOP reduction and use of medications are better with two-site surgery,” Dr. Budo said.

Dr. Menapace said he is not in favor of simultaneous procedures. Filtering surgery may be followed by hypotony that, combined with cataract surgery, could cause synechiae because of the fibrin formation in the anterior chamber.

“First do your cataract surgery, and wait until the anterior segment has stabilized. Measure the IOP, and then decide if you need to do an IOP-lowering filtration surgery. Only in patients who have advanced glaucomatous optic atrophy and are not likely to return for a second procedure [do] I do simultaneous surgery,” he said.

Surgeons should exercise extreme caution when performing phacoemulsification in patients with acute angle closure because the corneas of these patients have been subjected to inflammation in the past with IOP spikes and are more susceptible to endothelial cell loss, Dr. Braga-Mele said.

“When performing cataract surgery in patients who have had previous attacks of acute angle closure, I suggest that people use a dispersive viscoelastic to coat the cornea and protect it, and minimize their power usage and minimize the fluidics through the eye. Or else we’re going to see corneal edema much more often in these patients,” Dr. Braga-Mele said.

Postoperative IOP can decrease or spike in patients with open-angle glaucoma. Dr. Braga-Mele said she monitors IOP at 4 hours and 24 hours postoperatively. Some patients are sensitive to topical steroids or viscoelastic material that is not removed.

“You have to be careful with these patients postoperatively that they don’t either get an early spike or a late spike 2 weeks postop from the steroids,” she said.

IOL choice is also a sensitive issue for glaucoma patients. Patients with pseudoexfoliation glaucoma should not receive multifocal or accommodating IOLs because of possible zonular instability, Dr. Braga-Mele said.

“When you don’t have an intact zonular-ciliary body complex, those lenses don’t work well. So, I would urge you to stay away from them,” she said.

However, premium IOLs can be used for patients with chronic controlled glaucoma, provided there is no optic nerve damage or visual field loss, Dr. Braga-Mele said.

Glaucoma patients should undergo rigorous imaging of the optic nerve, optic disc and macula with optical coherence tomography, Heidelberg Retina Tomograph and fundus photography, she said.

Dr. Chu echoed Dr. Braga-Mele’s thoughts about preoperative screening of cataract patients with glaucoma.

“We have to manage the medical condition of glaucoma, make sure their pressure is under control,” he said. “We have to assess the degree of the glaucoma, whether it’s mild, moderate or severe, to help us determine what the visual potential for the patient is.”

Cataract surgery alone may play a significant role in treating glaucoma in some cases, Dr. Chu said.

“In glaucoma, I think one of the benefits of cataract surgery is that it’s being learned that removing the cataract can actually help reduce the pressure even better than what was previously thought,” he said.

In addition, combined cataract surgery and minimally invasive glaucoma procedures such as canaloplasty are gaining favor for some indications, Dr. Chu said.

“That’s been a revolution in the sense of glaucoma surgery,” he said. “It’s gotten less invasive, with quicker recovery, better results with fewer complications and fewer serious, sight-threatening complications. If the IOP is not well-controlled and the glaucoma seems to be advancing or is fairly advanced, I think doing a combination procedure is more reasonable. … We’ve learned that treating glaucoma sooner is better than waiting until it’s too late.”

Diabetes

Cataract surgery is a common event in diabetic patients, with a tendency to occur more often and earlier than in the general population. The Wisconsin Epidemiologic Study of Diabetic Retinopathy reported that the cumulative incidence of cataract surgery in patients with type 2 diabetes is about 25% over 10 years. Other epidemiological studies suggested a greater risk of cataract in diabetic patients who are between 50 and 65 years.

“It’s important for surgery that their diabetes is managed well by their family doctor or endocrinologist,” Dr. Braga-Mele said. “Their blood sugar should be in an ideal range when you do cataract surgery on these patients because their healing and their outcomes will be better.”

Diabetic retinopathy and neovascularization should be controlled before a patient undergoes cataract surgery, she said.

“If they have three- or four-quadrant diabetic retinopathy or proliferative diabetic retinopathy, if you do surgery on them, you can stress that eye and make them progress, and then it’s not as easily treated,” she said.

Patients with controlled blood glucose levels may be eligible for any type of IOL. However, uncontrolled blood glucose or intraoperative complications may cause a progression to nonproliferative or proliferative diabetic retinopathy, Dr. Braga-Mele said.

“I work in conjunction with a retina specialist,” she said. “I’ll send them off and have their diabetic retinopathy assessed and treated, either with an injection or with laser, and then perform cataract surgery on them.”

When performing cataract surgery in diabetic patients, the crucial aspects of routine surgery that help minimize inflammation and permanently preserve visual access to the retinal periphery become even more necessary.

“We need atraumatic surgery to minimize the inflammatory response and avoid induction or exacerbation of diabetic retinopathy and macular edema. Even in uneventful cataract surgery, the risk of developing macular edema is high in diabetic patients, up to 10%,” Dr. Menapace said.

On the other hand, maintaining capsule transparency is crucial to ensure visualization of the ocular fundus. The need for monitoring retinal conditions and for vitreoretinal surgery may easily arise in these patients.

Reduction of inflammatory responses begins with the incision. Dr. Menapace recommended aiming at the smallest possible incision size while avoiding vascularized tissue and at the same time ensuring maximum deformation resistance.

“Limbal incision is preferable. If you want to use corneal incision, keep it very small and perform [microincision cataract surgery] to ensure wound and corneal stability,” he said.

The capsulorrhexis should be performed bearing in mind that circumferential rhexis-optic overlap is essential for posterior capsular opacification (PCO) prevention but that minimal overlap of a large optic diameter IOL is important to provide the largest free optic diameter possible.

“If you don’t overlap, then you’ll lose the barrier effect of the sharp optic edge very quickly and PCO follows,” Dr. Menapace said.

After nucleus removal, the capsular bag must be thoroughly cleaned from any residual cortical material to prevent Soemmering’s ring formation. Soemmering’s ring impairs retinal visualization and treatment and predisposes to secondary edge barrier failure and delayed retro-optical PCO, Dr. Menapace explained.

IOLs should have a sharp posterior edge and preferably a large 6.5-mm optic diameter. Looped three-piece optic designs with slim haptic junctions are more suitable for fundus visualization and to avoid breach formation in the lens epithelial cell barrier at the optic-haptic junction, a typical site where the edge finally fails. As far as IOL material is concerned, hydrophilic acrylic should be avoided because it tends to develop calcium deposits in vitrectomized eyes. Hydrophobic acrylic is probably the best choice, but silicone should not be excluded.

“Several studies demonstrated that silicone has the lowest PCO and YAG rate, while with acrylic, including hydrophobic acrylic, the barrier effect is lost over time. It is true that silicone lenses in post-YAG eyes have the problem of silicone oil adhesion in case of silicone oil tamponade, but other lens biomaterials are not immune to this complication,” Dr. Menapace said.

Moreover, should this complication occur and should lens exchange be unavoidable, the soft silicone optics are the easiest to remove from the capsular bag, he said.

Posterior capsulorrhexis potentially provides a second line of defense against PCO. However, closure rate in diabetic patients is higher than average. Dr. Menapace’s technique of posterior optic buttonholing, in which the IOL optic is entrapped into the posterior capsulorrhexis opening, avoids rhexis closure and creates a permanent barrier against lens epithelial cell migration.

Finally, intensified and prolonged treatment with NSAIDs and corticosteroids should be administered, and anti-VEGF injection should be considered in case of manifest diabetic macular edema.

“If cataract surgery can be delayed, consider anti-VEGF injection as a preoperative treatment and wait to perform surgery until the edema is dried out. If cataract removal cannot be delayed, as in cases of dense cataract, do your surgery and perform anti-VEGF injection at the end of the procedure,” Dr. Menapace said.

Outcomes

Ocular comorbidity is a significant limiting factor on final visual outcomes from cataract surgery. Having made the necessary distinctions between different stages of coexisting diseases, visual outcomes remain poor compared with those of patients with no ocular comorbidity.

“We must avoid building up false expectations in our patients and be clear [about] what they can and cannot expect from surgery,” Dr. Menapace said.

Additional chair time and a sincere but positive and unequivocal message about the likely outcomes of surgery will help patients enjoy the benefits rather than suffer the limitations of the procedure, he said.

Timing is paramount because postponing surgery may result in hard nuclei, which present various challenges, Dr. Braga-Mele said.

“I don’t think it’s good to wait until the cataract progresses to a dense cataract,” she said. “We don’t necessarily have to wait until it’s advanced. … It’s a fine line as to when it’s in the best interests of the patient. I think that’s what we need to look at.”

Delaying cataract surgery is generally advisable, but there are exceptions, especially for patients with significant glaucoma, Dr. Chu said.

“You don’t want to do unnecessary surgery, obviously, but with the modern technologies of phacoemulsification and small incisions, I think cataract surgery has gotten safe enough where it can be thought of, especially in a glaucoma patient, as an important step in therapy for these patients to remove cataracts,” he said.

Such an intervention may resolve drug compliance issues and yield other significant benefits.

“There’s less cost, and there are other benefits for everyone involved,” Dr. Chu said. – by Michela Cimberle and Matt Hasson

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Customized treatment plan needed for cataract patients with comorbidities

References:

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• Rosa Braga-Mele, MD, FRCSC, can be reached at 245 Danforth Ave., Suite 200, Toronto, Ontario M4K 1N2, Canada; 416-462-0393; email: rbragamele@rogers.com.
• Camille Budo, MD, can be reached at Sint-Godfriedstraat 8, (Sint-Truiden), Melveren 3800, Belgium; 32-11-689684; fax: 32-11-688286; email: camille.budo@skynet.be.
• Y. Ralph Chu, MD, can be reached at Chu Vision Institute, 9117 Lyndale Ave. South, Bloomington, MN 55420; 952-835-0965; fax: 952-835-1092; email: yrchu@chuvision.com.
• Rupert Menapace, MD, can be reached at the Medical University of Vienna, Vienna General Hospital, Department of Ophthalmology, Waehringer Guertel 18-20, A-1090 Vienna, Austria; 43-1-404007941; fax: 43-1-404006630; email: rupert.menapace@meduniwien.ac.at.
• Disclosures: Dr. Braga-Mele is a consultant for Abbott Medical Optics, Alcon and Bausch + Lomb. Drs. Budo and Menapace have no direct financial interests in the products discussed in this article, nor are they a paid consultants for any companies mentioned. Dr. Chu is a consultant for Abbott Medical Optics and Bausch + Lomb.