OSNAPAO: Cataract surgery in diabetic patients requires high level of care, teamwork with retina specialists

Cataracts develop more frequently and at an earlier age in patients with diabetes, according to clinical and epidemiological studies. With the rapid increase of both type 1 and type 2 diabetes worldwide, the number of cataract surgeries in diabetic patients is steadily on the rise.

Although phacoemulsification with small incisions has greatly enhanced the safety of the procedure, diabetic eyes still have a higher risk of intraoperative complications.

“Diabetic eyes have many disturbances within the anterior segment, and this may make cataract surgery more difficult than in a non-diabetic case. They also have a higher risk of miosis, a more fragile lens capsule and tend to develop more inflammation and transient elevation of intraocular pressure. A higher incidence of angiographic cystoid macular edema has also been documented,” Amar Agarwal, MS, FRCS, FRCOphth, OSN APAO Edition Board Member, said.

Phacoemulsification for cataracts grade 1 to 3 is preferable because this technique with a small incision reduces the postoperative breakdown of the blood-retinal barrier and leads to less anterior chamber reaction during the first postoperative week, he said. However, if extracapsular cataract extraction is performed, more inflammation is expected due to more tissue manipulation, extended surgical time and multiple sutures.

Teamwork begins with preoperative assessment

A combined approach by anterior and posterior segment specialists is the most effective way to manage diabetic cataracts, according to Agarwal. Cooperation from the patient and treating physician in terms of diabetic control is also essential.

“Blood investigations, which include fasting and postprandial blood sugar, are taken before doing any plan for surgery. Glycosylated hemoglobin shows the blood glucose control over the last 6 months. In patients with uncontrolled diabetes or HbA1c more than 8%, we need cooperation with the patient’s physician to reduce the blood glucose before we proceed with surgery,” Agarwal said.

Once the anterior segment surgeon has recommended cataract extraction, he said, the retina consultant should give clearance for surgery after performing dilated fundus examination, fundus fluorescein angiography in specific cases and, if required, OCT.

According to Susanne Binder, MD, OSN Europe Edition Board Member, if no retinal changes are seen, diabetic patients can be treated as normal cataract surgery patients. In case of background retinopathy, which does not necessitate laser treatment, the patient is followed more closely after surgery to see how the retinopathy evolves.

“Only in case of proliferative diabetic retinopathy, cataract surgery should be postponed and the pre-existing condition treated with laser. Anti-VEGF or corticosteroid injections might be used, depending on the surgeon’s preference, in case of diabetic macular edema,” Binder said.

Having a clear picture of the retinal conditions is mandatory because operating on a patient with advanced retinal complications “is like uncorking a champagne bottle,” according to Francesco Bandello, MD, FEBO.

“The retinopathy runs wild and progresses rapidly in a way you cannot always control,” he said.

Fortunately, cataracts nowadays are rarely so dense at presentation that they do not allow a good view of the ocular fundus or an OCT scan.

“If there is a risk that the retinopathy might get worse, I inject an anti-VEGF at the time of surgery. This will protect the eye for at least 1 month. I also apply a suture to the wound, in case laser is needed later on. I more rarely use steroids because I take into account that an infection might occur, and steroids would depress the immune defenses,” he said.

In the rare cases in which the cataract is too dense to allow preoperative OCT, Binder uses intraoperative OCT to examine the retina immediately after lens removal. If there is edema, she promptly administers steroids or an anti-VEGF.

“If you don’t have an intraoperative OCT, you have to see the patient very soon after the surgery, do your OCT examination, and if you see some edema, you must treat it quickly with corticosteroids or anti-VEGF,” she said.

Surgery

Surgeons do not need to change their routine cataract procedure when dealing with a diabetic patient, according to Ehud Assia, MD, OSN Europe Edition Board Member.

“The only thing I do is provide the patients with NSAIDs, particularly nepafenac, if there is some activity. If the retina is quiet, well-controlled, it is not needed. I use the same parameters as for routine surgery and don’t change my surgical technique,” he said.

Binder routinely performs surgery with intraoperative OCT and looks at the fovea at the end of surgery.

“In a normal healthy patient, foveal thickness increases after cataract surgery by no more than 8 μm. This increase is transient and subclinical. In diabetic patients, the swelling tends to be greater, but we have no data yet to prove that this is the rule,” she said.

According to Agarwal, the surgical technique may stay the same, but surgeons must be aware that the anatomical changes and more fragile structures of the diabetic eye require attention and a more cautious and delicate approach.

“Lens capsule changes may affect performing capsulorrhexis during phacoemulsification. The lens capsule is thickened and more friable, leading to more frequent rupture during surgery. Intraoperative miosis and iris abnormalities are expected in diabetic eyes due to vacuolated iris pigment epithelium. Bleeding from the iris, due to pre-existing neovascularization, can happen during phacoemulsification. Basement membrane abnormalities can precipitate to unexpected intraoperative Descemet’s membrane detachments or improper postoperative epithelial healing. Difficulty in cortex removal can be expected during cortical wash due to the sticky nature of cataract. Wound healing and wound stability are another factor, which again will be affected in diabetic eyes,” he said.

In eyes with cataract along with significant vitreous hemorrhage, phacoemulsification and pars plana vitrectomy will be combined, and in this scenario, a team approach with a vitreoretinal colleague is preferred, he said.

IOLs

It is generally agreed that silicone IOLs should be avoided. Should the patient need vitrectomy due to vitreous hemorrhage, the contact with silicone oil would produce changes to the lens.

“In the past, intraocular lens implantation was considered to produce inflammation, and we feared to implant it in a diabetic patient because of the stronger reaction and maybe vessel growth on the lens. Now we know it is not true. Aggressive diabetic retinopathy may produce vessel growth everywhere, on the iris and retina and on any given scaffold, but this has nothing to do with the lens itself,” Binder said.

Both hydrophilic and hydrophobic acrylic lenses work well, according to Assia.

“Silicone lenses are better avoided, and anyway there are very few silicone lenses on the market now. Acrylics do very well,” he said.

According to Agarwal, hydrophobic acrylic lenses have the lowest propensity to silicone oil adhesion and may be the IOL of choice in diabetic patients in anticipation of vitreoretinal surgery.

In eyes with intraoperative posterior capsular deficiency or inadequate capsules, Agarwal recommends his glued IOL technique.

This will prevent secondary surgical procedures and the need for scleral fixation sutures.

Anterior capsular phimosis is more common in diabetic patients. Therefore, according to Agarwal, the capsulorrhexis should be larger than normal but smaller than the IOL optic diameter to prevent posterior capsular opacification (PCO). Because diabetics are more prone to PCO, a square-edge design is recommended, he said.

As far as premium IOLs are concerned, toric lenses are a possible option.

“I use toric but not multifocal lenses. Although there is no absolute contraindication, I would not recommend these lenses to diabetic patients,” Assia said.

Postoperative course requires vigilance

The classic combination of steroids, NSAIDs and antibiotics for 3 to 4 weeks is normally used, but NSAIDs can be used for longer periods, from 5 weeks to 2 months, particularly if there are signs of inflammation.

Fibrin reaction might be seen more frequently. The reported incidence in diabetic patients is up to 13.7%, Agarwal said.

The follow-up schedule is basically the same as in non-diabetic patients, but if there are signs of inflammation, or if the patient reports pain and vision loss, closer follow-up visits are needed.

“Generally speaking, if previous retinal lesions are treated well before surgery, there is little chance of reactivation. Different is the case of a patient with active lesions that are likely to be worsened by cataract surgery. In such cases, a close follow-up is necessary,” Bandello said.

A multicenter study conducted by the DRCR.net in a group of 293 patients showed that eyes with a history of DME treatment and/or DME immediately before cataract surgery are at higher risk for developing macular edema. The study authors recommended that“clinicians should continue to maintain vigilance in diabetic patients after cataract extraction even when central ME is not present immediately prior to cataract surgery.”

In case of macular edema developing postoperatively, anti-VEGF injections are currently recommended as first-line treatment. However, Binder believes that corticosteroids better comply with the multifactorial origin of DME than anti-VEGFs, which are targeted against only one factor. Anti-VEGFs have the advantage of fewer side effects, but they might cause fibrosis of the vitreous.

“If the patient has already some tractive vitreous changes, the use of anti-VEGF could be dangerous,” she said.

Bandello agreed that corticosteroids are ideal to control the inflammatory component and the cascade of events leading to edema and severe retinal complications in diabetic patients.

“Particularly in the form of intravitreal implants, steroids provide long-lasting protection and are particularly effective in cases of chronic DME. Not at the time of surgery, but some time before or after cataract surgery, steroids are a viable option. In recent-onset DME, anti-VEGFs should be preferred,” he said.

In the postoperative management of patients with diabetic retinopathy, and especially with macular edema, cooperation with the retina specialist is vital.

“Most complications of cataract surgery in a diabetic patient are retinal; therefore, an interdisciplinary approach is necessary,” Assia said. “Cataract surgery is an acute event. DR is a chronic event. The cataract surgeon can deal very well with preoperative evaluation, surgery and short-term follow-up, and then the patient should be in the hands of the retina specialist again. I don’t need a retina specialist during surgery, but I do during the follow-up.” – by Michela Cimberle

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For more information:

Amar Agarwal, MS, FRCS, FRCOphth, can be reached at Dr. Agarwal’s Eye Hospital, 19 Cathedral Road, Chennai, India 600086; email: dragarwal@vsnl.com.

Ehud Assia, MD, is director of the Department of Ophthalmology at the Meir Medical Center and medical director of the Ein Tal Eye Center in Tel Aviv. He can be reached at 17 Brandeis St., Tel Aviv 62001 Israel; email: assia@netvision.net.il.

Francesco Bandello, MD, FEBO, is chairman of the Department of Ophthalmology, University-Vita Salute. He can be reached at Scientific Institute San Raffaele, Milano, Italy; email: bandello.francesco@hsr.it.

Susanne Binder, MD, is professor and chairman of ophthalmology at Ludwig Boltzmann Institute for Retinology and Biomicroscopic Laser Surgery, Vienna. She can be reached at Rudolph Foundation Clinic, Juchgasse 25, 1030 Vienna, Austria; email: susanne.binder@wienkav.at.

Disclosures: Agarwal reports he is a consultant for Abbott Medical Optics and Bausch + Lomb. Assia reports he is a consultant to Hanita Lenses. Bandello reports he is a consultant to Alcon, Allergan, Bausch + Lomb, Genentech, Novartis, Sanofi Aventis, Farmila-Théa, Bayer, Hofmann La Roche, Alimera Sciences, Novagali Pharma and ThromboGenics. Binder reports she is a consultant to Carl Zeiss Meditec.