Cataract Surgery and Coexisting Conditions
Performing phaco on patients with other ocular diseases and preconditions presents challenges and considerations.
BY JOHN PARKINSON, ASSOCIATE EDITOR

Cataract surgery can be a relatively straightforward procedure with limited preoperative considerations, provided a patient does not have any coexisting chronic ocular conditions. However, when a cataract surgery candidate suffers from conditions such as glaucoma, AMD or diabetic retinopathy, or is at risk for developing cystoid macular edema (CME), ophthalmologists must take into account these diseases before proceeding with surgery.

While understanding and treating patients' coexisting conditions is more time consuming and can be more challenging, the effort can provide patients with a better quality of life. Ophthalmology Management spoke with several physicians and asked them how they treat and manage coexisting ocular conditions when cataract surgery is necessary, decide on the best IOLs to implant for these patients, and evaluate what special techniques can be used in surgery.

Listening and Providing Realistic Expectations

When dealing with patients who have retinal disease such as AMD, I. Howard Fine, M.D., says taking the time to actively listen to patients is an important first step because through the course of these conversations, it is often decided whether or not cataract surgery is something that would improve patients' lives. "We talk with them [and listen] at length about how they are living and what the quality-of-life impact of their visual deficit [from retinal disease and cataracts] is," says Dr. Fine.

In doing so, he often finds patients grateful to receive any help in providing better visual acuity. For example, he points to patients who may have been able to drive last year, but cannot now because they may have lost two lines off the Snellen Chart and are no longer legally allowed to drive.

"Sometimes, by removing what appears to be a relatively insignificant cataract in the presence of macular degeneration or diabetic retinopathy, we get major improvements from the patient's perspective," says Dr. Fine. "If you bring a patient's vision from 20/60 to 20/40 they can not only read, they can drive."

Making the decision to perform cataract surgery is an important one, but another significant aspect of the preoperative evaluation is instilling realistic expectations about a surgery's potential outcome. While surgeons can often still deliver a good result for cataract patients with glaucoma, AMD or diabetic retinopathy, the additional challenge of coexisting conditions may shape their preoperative discussions with patients.

Francis Mah, M.D., also believes in providing patients with vision that will enhance their quality of life, and makes sure to prepare them for the surgery by providing appropriate expectations when coexisting conditions are present.
"If you have patients with the wet form of macular degeneration and they have scotoma in the central vision, they are pretty desperate to see better," says Dr. Mah. "When a retina specialist recommends cataract surgery or when you start discussing it, the first thing that some patients start thinking about is their friends, relatives or someone they have heard of who went from having difficulty seeing to 20/20." For some patients with severe retinal disease, that kind of expectation could be detrimental to their well being postoperatively.

Dr. Mah also says there is anecdotal evidence to suggest that in some patients with dry AMD, visual conditions worsen following cataract surgery, so this should be relayed to patients as well. Dr. Mah surmises an inflammatory component of AMD might affect how these patients who undergo phaco might see postoperatively.

For Robert J. Noecker, M.D., a glaucoma specialist, the discussion differs depending to what degree of disease the glaucoma patient suffers. For his patients with minimal to no visual field loss, he advises them as he would for patients with cataracts and no glaucoma. However, for patients with severe glaucoma, he alters his message. "What I tell patients is, 'we can't be a 100% sure how much your vision will improve,'" explains Dr. Noecker. "Unfortunately, many of the symptoms are exactly the same for glaucoma and cataract." As such, he informs patients with severe glaucoma that while they may have successful cataract surgery, the glaucoma may still limit their vision and it must be addressed.

Balancing Cataract and Glaucoma Treatment

When seeing cataract surgery candidates with coexisting conditions, surgeons must weigh the severity of the existing conditions along with the need for cataract removal before proceeding with a course of treatment.

For patients with a more aggressive form of glaucoma that needs to be addressed surgically, Dr. Noecker's preference is to perform the cataract surgery first and have the patient recover from that procedure before performing a trabeculectomy. A patient's IOP is typically more predictable following cataract surgery, according to Dr. Noecker. Conversely, IOP levels can vary greatly following filtering surgery, so if IOP rises after the second surgery, Dr. Noecker can treat it without having to worry about performing another procedure.

He also prefers to perform phaco and trabeculectomy separately, because when he performs a combination procedure, ocular inflammation occurs both inside the eye and in the conjunctiva.

Dr. Noecker addresses inflammation control by beginning patients on a course of steroids following cataract surgery for the 4 weeks leading up to the glaucoma surgery. This way, he can decrease potential inflammation in the conjunctiva and help quiet the eye for a better trabeculectomy procedure.

Another potentially beneficial side effect to staggering the surgeries is that some patients' IOPs drop following cataract surgery. While Dr. Noecker says these results are variable, he has seen some patients have it last for as long as 10 years.

In preparing patients for cataract surgery, Dr. Noecker will start to take patients off certain medications. "The first thing we do when getting people ready for surgery is look at the medications they are on. There are reports that prostaglandin analogues, especially Xalatan (latanoprost, Pfizer), are associated with higher rate of inflammation and cystoid macular edema."

If a patient has manageable glaucoma, he will discontinue usage of the IOP-lowering medications temporarily, but if the patient has more advanced glaucoma, and he decides to keep the patient on drops, he will treat them preoperatively with an NSAID to minimize the prostaglandin release that will occur during phaco.

Dr. Noecker says the physical characteristics of patients with glaucoma present challenges.

"Glaucoma patients tend to have a greater rate of smaller eyes as well as some with bigger myopic eyes and we have to recognize the technical challenges that these
nontypical anterior segments may present. There is also a very high rate of exfoliation," explains Dr. Noecker. As such, he will have capsular tension rings for zonular support and pupil expanders for small eyes on hand in the operating room during cataract surgery.

Glaucoma specialist Thomas Samuelson, M.D., says medication and technology-based therapies have evolved to help reduce the number of phaco and filtering combination surgeries.

"As the medicines and the lasers for glaucoma [treatment] have gotten better, we probably do fewer combined procedures than we did in the mid-1990s," explains Dr. Samuelson.

However, for the serious glaucoma sufferers whose IOP is uncontrolled despite medication and laser treatments, filtering surgery may be necessary in addition to cataract removal. In such cases, Dr. Samuelson will often perform a combination procedure. "Occasionally, I'll take the cataract out because you are already going to the operating room and an early or moderate cataract is likely going to progress as a result of the surgery, so you are often better off doing both operations at once."

Dr. Samuelson will often see the condition of the crystalline lens as an indicator to how he will treat glaucoma.
"If a patient has a clear lens, we will often treat them [with medication] or with a laser, and we'll maintain that treatment until they develop a cataract," explains Dr. Samuelson. "When a patient with glaucoma gets a cataract where surgery is warranted, we [ask the question], 'should we treat the glaucoma surgically at the same time as the cataract and therefore free them up from their glaucoma medications, or should we just take the cataract out and continue to treat the glaucoma medically postoperatively?' The time of cataract surgery is a pivotal point for patients with glaucoma." 

For those patients who have manageable glaucoma, but are going to have their cataracts removed, Dr. Samuelson will often use an aqueous suppressant postoperatively because occult, residual viscoelastic left in the eye or intraoperative inflammation can cause IOP to rise sharply. "Those conditions could lead to a pressure spike in a patient with glaucoma where it might have been perfectly well-tolerated in a patient with a normal outflow of aqueous."

IOL Biocompatibility and Selection

So much has been studied and written on the topic of IOL biocompatibility and selection, that understandably, there are varying attitudes toward the subject. Surgeons' IOL preferences often depend on what they believe about an IOL's physical properties or how the lens optics perform in the presence of a patient's coexisting condition.

The first generation of silicone IOLs were problematic, according to surgeons interviewed for the story. "Early silicone was prone to giant cell deposits building up on the lens, and in some cases, interfering with vision. That really set the framework for the acrylic format," explains Dr. Samuelson. However, with the advent of the newer silicone IOLs, Dr. Samuelson believes there are several good silicone IOLs currently available. While Dr. Samuelson prefers recent generation silicone IOLs, he is not adamant that silicone IOL materials are superior to other materials such as acrylic. Nonetheless, he does believe strongly that silicone is at the very least equivalent to other IOL properties.

Dr. Noecker also believes the new silicone IOLs have progressed technologically to the point IOL material itself is not a factor in visual acuities or complications like posterior capsule opacification (PCO). However, he does think the type of IOL edge still influences the incidence of PCO.

"The nice thing about [today's] silicone lenses is you can get them through small incisions and they are easy to fold and easy to get into the eye," explains Dr. Noecker. "I think any PCO issues are predominantly from a lens' design; the lens' edge and amount of anterior capsule overlap will determine the PCO rate. It's really not so much a material issue."

A conventional belief currently shared by many surgeons is that acrylic IOLs should be used instead of silicone lenses, especially in patients with diabetic retinopathy. Dr. Noecker believes this to be true, especially if the patient is likely to undergo a vitrectomy in the future.

Dr. Fine uses acrylic IOLs in patients with diabetic retinopathy. "We try to use acrylics 100% of the time with diabetics, because it keeps the door fully open for posterior segment intervention and if necessary, the use of silicone oil," says Dr. Fine. He says silicone oil forms bubbles on silicone IOLs that cannot be removed.

On the overall subject of IOL selection, Dr. Fine says he tries to tailor the IOL material, design and power for individual patients. "In every patient, we are trying to address their refractive desires, as well as our own concerns with respect to their history, anatomy and pathophysiology, so multiple considerations go into our choice for IOLs."

While hydrophilic acrylic IOLs are not used in the United States because of reports of calcification, Randall Olson, M.D., says internationally these IOLs seem to be viewed as the best type of lenses with regard to
biocompatibility. However, he says if the calcification issues are resolved, these IOLs might begin to be utilized widely in patients with retinal diseases or at risk for retinal complications in the United States. Dr. Olson believes the hydrophilic properties make it the most suitable to the eye, but he acknowledges no studies have proven it thus far.

Retinal Disease

Dr. Olson believes a good preoperative scanning for any potential ocular pathology is essential in patients with retinal disease, and if any questions should arise for the cataract surgeon, a consultation with a retinal specialist is warranted.

"It's a smart idea, when in doubt, to have that additional examination and comments from a vitreoretinal physician who says, 'we have A, B and C medical problems, but we have done as much as can be expected [medically for the coexisting conditions] and I think cataract surgery makes sense,'" says Dr. Olson. He also says that adding a posterior segment evaluation is a way of taking a proactive risk management approach because a complication such as retinal detachment could lead to a malpractice suit.

When performing phaco on patients with retinal disease, Dr. Olson is particularly cautious to avoid potential complications due to the delicate nature of patients with retinal disease. "I'm going to take extra pain to make sure I have good hydrodissection and hydrodelineation. With a [nuclear] fragment, I'm going to spend extra time, maybe even visco-elevate rather than go after it if I think its near the capsule."

Dr. Olson believes the reason patients with peripheral retinal disease and vitreoretinopathy, as well as high myopia, are at higher risk for developing retinal detachment following cataract surgery is, "the hyper-deepening and collapsing of the anterior chamber, so that the lens position is moving forward and backward — all of which accentuates a vitreous breakdown. This can lead to premature posterior vitreous detachment or other forces on the peripheral retina."

As such, Dr. Olson says performing bimanual microincision phaco may help avoid retinal detachment. He says anterior chamber stability and avoidance of hyper-deepening throughout the procedure are key aspects, and he predicts bimanual microincision will become more significant for retinal patients because surgeons who use the technique can more easily control the anterior chamber throughout the procedure.

"As we move forward, we may easily come to a time where we are as concerned about having an absolutely stable anterior chamber through the entire case as we are now worried about not breaking the capsule," says Dr. Olson.

With FDA approval of two more NSAIDs this year, ophthalmologists have more choices in how they want to treat inflammation. For patients with AMD or diabetic retinopathy who are at higher risk for inflammation, some doctors prefer to start treating patients preoperatively with NSAIDs and continue right up to just before the procedure, and then also treat postoperatively.

Dr. Mah will treat patients with retinal disease with NSAIDs throughout. "I like to use NSAIDs four times a day for at least 3 or 4 days before the cataract surgery. Then the day of surgery, they get 4 drops within a 2-hour period, just before. Following surgery, I like to use NSAIDs four times a day for 4 to 6 weeks."

Along with inflammation associated with retinal conditions, CME can be a troublesome complication. Dr. Mah believes using NSAIDs has reduced the incidence of this complication. As evidence, he points to the controversy years ago with the use of NSAIDs and corneal melts during clear corneal phaco procedures. As a result, Dr. Mah stopped using NSAIDs for routine cataract surgery and noticed an increase in the number of CME cases. Today, he uses NSAIDs and he has seen this complication decrease.

Intraoperatively, he will use a one-time Kenalog
(triamcinolone, Bristol Myers Squibb) injection for patients with a history of macular edema, whether CME or diabetic in nature, or those at high risk for edema postop. "Once I put the lens in the bag, I do automated irrigation and aspiration to take out about a third of the viscoelastic so the eye is a little softer. I measure 3.5 mm from the limbus and I inject triamcinolone into the vitreous cavity."

Dr. Fine says the bimanual micromanual phaco technique can help prevent CME in diabetics.

"We think in diabetic retinopathy [patients], there is a great advantage to bimanual microincision phaco. We can keep the irrigator in the eye and keep the eye infused, and therefore, never have hypotony, which can facilitate
vascular leakage."

Continuing Efforts

While cataract surgery is a sophisticated, mature procedure that can deliver excellent results, ophthalmologists are always striving to improve the procedure and all aspects related to it. As cataract surgery works toward becoming even more refined, simultaneous glaucoma and posterior segment pathology studies are being conducted to begin to offer viable treatments to patients with these conditions. With numerous research studies in various areas, there is reason to be optimistic there may come a time when cataract patients with coexisting conditions will be able to receive not only a successful phaco procedure but treatment for their chronic conditions to fully revive their visual acuities.