Cataract surgery with comorbidities requires careful surgical management

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Rupert Menapace, MD, said that comorbidities can impact cataract surgery in multiple ways, calling it “not just standard cataract.” Image: Menapace R

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

Epidemiological studies including the European Cataract Outcome Study, international registries such as the European Registry of Quality Outcomes for Cataract and Refractive Surgery and national data collections are consistent in findings, reporting an overall 34% to 36% incidence of ocular comorbidity in cataract patients.

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.

In developing countries such as India and China, cataract surgeons are also increasingly experiencing the difficulties that coexisting pathologies create.

India currently has the highest number of diabetic patients in the world, with 11% of the urban population and 3% of the rural population older than 15 years having diabetes.

The prevalence of AMD in Asian patients has not been found to be lower than in Caucasian patients, and it has been reported as ranging from 1.4% to 12.7% for early AMD and 0.2% to 1.9% for late AMD. Studies carried out in India have found a significant association between AMD and cortical cataract, with a 3% prevalence of cataract in AMD patients.

“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.

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 is still common among ophthalmologists. 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.

Gábor B. Scharioth

Gábor B. Scharioth, MD, said that most of the evidence in favor of a correlation between cataract surgery and AMD progression was based on data from patients who underwent surgery with older techniques, which caused intensive intraocular trauma and postoperative inflammation.

“Today we perform modern phacoemulsification with implantation of foldable intraocular lenses through very small incisions, with extremely low complication rates and reduced postoperative inflammation. The risk for worsening of pre-existing ocular diseases is significantly lower,” he said.

Dr. Scharioth was personally involved in a retrospective study evaluating the risk for patients with dry AMD to progress to wet AMD after cataract surgery. Between 2000 and 2006 in 1,152 eyes of 696 patients with dry AMD, phaco with implantation of a clear IOL was performed; 344 eyes of 202 patients with dry AMD and cataract but with no cataract surgery in the follow-up period were used as controls.

“We did not find any significant difference between the two groups. The risk for newly developed neovascular AMD was about 2% in both groups after a minimum follow-up of 12 months,” he said.

“Keeping these results in mind, I do not think that modern phacoemulsification with IOL implantation puts my patients at higher risk for AMD development or progression,” he said. “However, I am strongly convinced that a pre-existing wet AMD should be, whenever possible, diagnosed and treated preoperatively. In case of doubt, we perform fluorescein angiography and spectral-domain optical coherence tomography to exclude active wet AMD before cataract surgery.”

A precaution during the procedure is to use the lowest possible illumination to prevent extra retinal stress from free radicals.

In patients with wet AMD and choroidal neovascularization recurrences who have been previously treated with anti-VEGFs, simultaneous intravitreal anti-VEGF injection can be performed during cataract surgery.

“In these patients, I believe that there is indeed a risk of CNV recurrence, although surgery is carried out in the free interval and after we have proven that no activity of the choroidal neovascular complex is present. Anti-VEGF injection at the time of surgery may have a prophylactic effect, and then I recommend intensive follow-up and regular retinal examinations. Patients are recommended to use their Amsler charts and show up for consultation immediately if their vision worsens or metamorphopsia is noticed,” Dr. Scharioth said.

The use of blue-blocking IOLs in AMD patients has raised controversy among ophthalmologists. On one side are those who believe that implantation of a clear IOL makes the eye more vulnerable to phototoxicity, particularly by the blue light wavelength. On the other side are those who think that blue-blockers adversely affect luminance contrast and circadian photoreception and provide no tangible clinical benefits in exchange for the photoreception losses they cause.

The underlying question — does blue light increase the risk of developing AMD after cataract surgery? — so far has no univocal answer.

“Personally, I don’t believe in blue-filtering IOLs, but whenever I operate on a patient who has this type of IOL in the first eye, I do implant it also in the second eye,” Dr. Scharioth said.

Telescopic and prismatic lenses are currently under investigation and might become options in future years.

Amar Agarwal, MS, FRCS, FRCOphth, OSN Asia-Pacific Edition Editorial Board Member, performed the first worldwide implantation of Issac Lipshitz’s LMI-SI (OriLens) telescopic lens.

“The LMI is working on the principle of using mirrors to magnify the central image while the peripheral field remains normal,” he said. “It looks like a regular PMMA IOL, with a 5-mm to 6-mm optic and loops. The only significant difference compared to a regular IOL is its central 1.25 mm thickness.”

This special lens is designed to be positioned in the sulcus, over a regular bag-implanted IOL.

A regular phaco or extracapsular cataract extraction procedure with IOL implantation is performed, enlarging the incision to 5.5-mm at the time of inserting the LMI.

“It can also be used in patients who have previously undergone cataract surgery with IOL implantation. In these cases, it is still possible to offer the patient the opportunity of visual rehabilitation without having to undergo a complicated procedure such as explanation of the existing IOL and reimplantation of another telescopic device,” Prof. Agarwal explained.

He said that the initial outcomes are encouraging, and a trial with more patients and a longer follow-up will soon be conducted.

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.

Camille Budo

“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.

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.

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.

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.

“The important factor to realize here is that despite performing cataract surgery successfully in these patients, they do not benefit as much visually because of the coexisting pathology. Visual benefits from treatment are, after all, what actually affects the quality of life of the patients and what is meaningful to them, but there is unfortunately a significant difference between performing cataract surgery and being able to successfully rehabilitate the patient visually,” Prof. Agarwal said.

“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 to enjoy the benefits rather than suffer the limitations of the procedure, he said.

Dr. Scharioth said that there is a minority of patients, namely those with active neovascular AMD, to whom surgery should be denied because the chances of experiencing a dramatic worsening of the disease are too high. With other patients, risks and benefits should be discussed.

Timing is also important, because postponing surgery means in many cases having to deal with hard nuclei, which can lead to more traumatic surgery with more inflammation and a higher risk of complications.

“We should guide our patients to have cataract surgery at the right point, when the benefit for sight is high and the risk of surgery is relatively low,” he said.

When telescopic implants have completed trials and become more extensively available, surgeons might be able to offer a realistic chance of recovering reading vision to motivated patients with AMD or other macular lesions after cataract surgery, Prof. Agarwal said. – by Michela Cimberle

Would you consider using multifocal IOLs in patients with comorbidities such as AMD, glaucoma or diabetes?

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• Amar Agarwal, MS, FRCS, FRCOphth, is director of Dr. Agarwal’s Eye Hospital and Eye Research Centre. He can be reached at 19 Cathedral Road, Chennai-600 086, India; +91-44-28116233; fax: +91-44-28115871; email: dragarwal@vsnl.com.
• Camille Budo, MD, is associate professor at Maastricht University, the Netherlands. He can be reached at Sint-Godfriedstraat 8, (Sint-Truiden), Melveren 3800, Belgium; +32-11-689684; fax: +32-11-688286; email: camille.budo@skynet.be.
• Rupert Menapace, MD, is head of the Cataract & Intraocular Lens Service, University of Vienna Medical School. He 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.
• Gábor B. Scharioth, MD, is a senior consultant at the Aurelios Augenzentrum, Recklinghausen, Germany. He can be reached at scharioth@gmx.de.
• Disclosures: Prof. Agarwal has no direct financial interests in the products discussed in this article, nor is he a paid consultant for any companies mentioned. Dr. Budo has no direct financial interests in the products discussed in this article, nor is he a paid consultant for any companies mentioned. Dr. Menapace has no direct financial interests in the products discussed in this article, nor is he a paid consultant for any companies mentioned. Dr. Scharioth has no direct financial interests in the products discussed in this article, nor is he a paid consultant for any companies mentioned.