Dry Eye Screening & the Cataract Patient

Ocular surface dryness is more common than you think, and a significant obstacle to good postop vision for premium IOL patients.

By René Luthe, Senior Associate Editor

Everyone knows that the incidence of dry eye is increasing, and that it can pose a serious obstacle to quality of vision — and patient satisfaction — following refractive or cataract surgery. But is it really necessary to screen each patient for dry eye prior to surgery? After all, both laser vision correction and premium IOL implants are expensive enough already, especially in a down economy. Must there be the added expense and inconvenience of testing? According to cataract and refractive surgeon Mitchell Jackson, MD, of Lake Villa, Ill., the answer is a resounding yes. “The question shouldn't even be asked.”

Most ophthalmic surgeons wouldn't question that — at least, not for refractive patients. However, there's a strong case that all vision correction patients — both refractive and cataract — need to be screened for dry eye. Here is what surgeons in the know have to say, as well as the most effective screening methods and treatment plans that will have patients ready for surgery as soon as possible.

Nip Problems in the Bud

Dry eye is well known as a source of chronic, low-grade discomfort to those who suffer from it. Often less well known is its potential negative impact on cataract surgery outcomes. Yet according to these experts, the surgeon should screen cataract patients — specifically, premium IOL patients — for the very reason they do so for their refractive patients: Since these patients are paying a higher fee for a superior experience, they expect superior vision — right out of the gate. For multifocal lenses to meet their high expectations, a good tear film is essential, notes Amin Ashrafzadeh, MD, of Modesto, Calif., which means no dry eye.

As Miami's William Trattler, MD, explains, “an irregular cornea will degrade the optics” of premium IOLs.

Another, equally important issue that preoperative screening takes care of for the cataract/refractive surgeon is pre-empting the patient from concluding that the surgery is what caused their dry eye, as Kevin Waltz, OD, MD, of Indianapolis points out. If a poor quality ocular surface is identified during the preoperative evaluation, his practice informs the patient that it is a significant problem. “We tell them it is serious enough to delay their surgery,” he says. “Identifying and treating dry eye preoperatively leaves the patient with the impression that the dry eye is not related to the surgery and the surgeon is acting in the patient's best interest.”

Punctate staining using fluorescein dye. COURTESY OF WILLIAM TRATTLER, MD

But wouldn't the discomfort dry eye sufferers experience prevent them from blaming their surgery for the problem? Don't bet on it, according to Dr. Jackson. He notes that the PHACO (Prospective Health Assessment of Cataract Patients' Ocular Surface) Study, which surveyed cataract patients preoperatively, indicated that “most are not symptomatic of dry eye, even though they do have it. The gist is that patients aren't going to tell you they feel dry — you have to actually look.”

Thus, screening for dry eye/ocular surface disease is essential, he believes.

A Propensity to Miscalculate

But patient perceptions aren't the only thing to worry about: Dry eye can also result in inducted astigmatism, which can affect lens calculations, notes Leela Raju, MD, a clinical assistant professor of cornea, anterior segment and refractive surgery at UPMC Eye Center in Pittsburgh. “Especially in patients where you are thinking about doing a premium lens, such as a toric or a multifocal.”

Lissamine green staining revealed mild dry eye that required pretreatment to achieve optimal results. COURTESY OF WILLIAM TRATTLER, MD & PARAG MAJMUDAR, MD

Dr. Ashrafzadeh points out that dryness on the ocular surface also can throw off biometry, making the calculation “significantly erroneous,” he says. Additionally, dry eye can cause problematic shifts in keratometric value. “A one-diopter error in your keratometric measurement equals a one-diopter prescription error.” Not the outcome the patient had in mind when he chose the more expensive IOL.

Thus not only is it critical to treat dry eye before surgery, Dr. Ashrafzadeh says, it is critical to treat it before the biometry is performed.

For prospective cataract patients with autoimmune disease, however, ocular surface dryness poses much graver risks. Dr. Raju says that she has seen problems that began as mere dry eye turn into corneal melts — a prospect that would strike fear into the heart of any surgeon.

“That's because of the dryness,” Dr. Raju explains. “Then, with the inflammation that happens around the time of surgery, it can become something that you're not expecting.” While such patients are not the typical cataract case, they do demonstrate just how essential preoperative screening is for the common problem of ocular dryness.

Screening Steps

When it comes to detecting dry eye before surgery, these surgeons tend to rely on the same tried-and-true methods. Checking the patient's tear break-up time and fluorescein green staining were among the most often cited.

“I find that the tear break-up time is by far the most telling of the quality of their tear film and how comfortable they are. And fluorescein does a very good job of giving you the ability to look at the tear film and also note if there's any staining of the cornea,” says Dr. Ashrafzadeh.

Dr. Trattler touts the efficacy of a “good clinical exam.” He particularly emphasizes a clinical evaluation of the meibomian gland orifices. “That's very important,” he says. “It's something I look at in every single patient, even a nonsurgical patient, to judge the status of the meibomian glands themselves.”

Another screening tool he relies on is lissamine green staining to evaluate the ocular surface.

Dr. Ashrafzadeh, on the other hand, is skeptical of both lissamine green and rose bengal staining. “I find that it's a very late clinical finding and that by the time rose bengal picks up, the dry eye is already very evident.”

He believes the patient history is the most significant portion of the screening. “Talk with the patient, ask them some very basic questions: Do they have dryness of the eyes, do they feel that there's sand/grit in the eye, does the wind irritate their eyes? Does their vision fluctuate with blinking?”

Dr. Raju agrees with the importance of the patient history. For instance, dryness in the morning could be due to the rather common phenomenon of not completely closing the eye when sleeping. “It's really important to find out when those symptoms are the worst — that can give you an idea of exactly why the dryness is occurring.”

Dr. Raju also focuses on the patient's blink rate. She says that particularly in the elderly population, who may have had previous surgery, “neurotrophic cornea won't really signal the patient to be blinking at a normal rate, and that can result in dry eye.” Those who spend a lot of time on computers, of course, also show a reduced blink rate and are prone to dryness.

Topography as a screening tool is increasingly gaining popularity. Dr. Jackson is a proponent. “I recommend it. I actually do topography on all my patients because it will help identify irregular corneal shape as well as dry eye. It's certainly not a required test, but it's a helpful test.” However, it is required in premium IOL technology such as torics to aid in proper axis alignment and in presbyopia-correcting IOLs to be sure a patient is a candidate for laser vision candidacy postoperatively if needed.

Dr. Trattler agrees. He sees topography as being an essential screening tool for both refractive patients and cataract patients who will receive an advanced-technology IOL. “But it's not necessarily for a patient who is going to get a basic monofocal lens, in which there is not expectation of good uncorrected distance or near vision,” he says.

Topography shows a patient with poor ocular surface quality, poor image quality for the cornea, increased higher-order aberrations and decreased MTF. COURTESY OF KEVIN L. WALTZ, OD, MD

Treatment — Then Surgery

Once ocular surface dryness is identified, surgery must be postponed and treatment begun. As with other dry eye cases, a first step is to determine if it's a case of aqueous-deficient or evaporative dry eye. For aqueous deficiency, Dr. Jackson prescribes topical cyclosporine, and also considers punctal plugs, especially if a patient has a stage 3 disease based on the new DEWS updated definition for dry eye.

If the patient has hyperosmolarity, a hypotonic artificial tear such as Blink or TheraTears is indicated as well. Evaporative dry eye, on the other hand, typically is treated with topical azithromycin, warm compresses, topical steroids or antibiotic/steroid combinations, intraductal meibomian gland probing and/or the new FDA-approved thermal pulsation system.

Dr. Ashrafzadeh reports that in the vast majority of dry eye cases he sees, meibomian gland dysfunction (MGD) is the culprit, resulting in evaporative dry eye. “I probably put the figure at 95% evaporative dry eyes and 5% aqueous insufficiency.”

He too treats evaporative dry eye with azithromycin or another chronic, topical antibiotic, such as erythromycin ointment; alternately, he sometimes opts for flaxseed oil or minocyline pill orally. Some cases, he says, require a combination of the two methods.

One corticosteroid that has been shown to reduce inflammation following cataract surgery when given preoperatively is difluprednate. According to a study published last year by Donnenfeld et al,² 52 patients received either difluprednate 0.05% or prednisolone acetate 1% in one eye while the fellow eye received the alternative.² Prior to bilateral phacoemulsification, seven doses were administered over two hours, with three additional doses administered following surgery. “Difluprednate reduced inflammation more effectively than prednisone acetate, resulting in a rapid return of vision,” the authors concluded.

When the problem is aqueous deficient dry eye, Stephen Lane, MD, of Stillwater, Minn., addresses it with artificial tears followed by two weeks of Lotemax TID, at which point he adds Restasis BID. “I then treat with both for about 3-4 weeks, after which I stop Lotemax and use only Restasis and tears,” he explains.

Dr. Trattler likes to start treatment with the low-key option of warm compresses, though once it becomes clear that something stronger is required, he often prescribes Tobradex ST. “I like it particularly for the preoperative cataract patients,” he says. “It is a combination antibiotic, tobramycin and the steroid dexamethasone, to decrease the inflammation along the lid margin and also help to sterilize it in terms of any of the flora that could potentially be problematic after cataract surgery. To me, it's an excellent preoperative treatment, along with lid scrubs, to take care of MGD prior to surgery to help assure a better postoperative result.”

Dr. Trattler also is interested in TearScience's new Lipiview/LipiFlow System for preoperative care of patients with MGD. The device uses tear interferometry to visualize and measure the thickness of the tear film lipid layer and then expresses the meibomian glands with a “thermal pulsation system.”

“It may very well have a significant role in the preoperative care of patients because it is something that doesn't necessarily have to be done on a chronic basis,” Dr. Trattler explains.

Another treatment receiving a closer look is the use of preoperative punctal occlusion for dry eye prevention. In a study presented at this year's annual meeting of the Association for Research in Vision and Ophthalmology, eight of 36 contact lens wearers who presented for laser vision correction and had tested positive for dry eye syndrome were treated with punctal occlusion.³ The researchers report that at approximately five months postop, only 25% had dry eye complaints versus 40% for the patients who had not received punctal occlusion. A control group of contact lens wearers who tested negative for dry eye syndrome and did not receive punctal occlusion showed a rate of postoperative dry eye complaints of 35%.

Dr. Raju notes that it is rare that only one approach is necessary to remedy dry eye completely. “You don't always have to keep putting a lot of medications on the eye; there are a lot of ways to tackle it,” she says. The much-discussed strategies for managing the patient's environment will probably come into play, such as eliminating ceiling fans at night or possibly using sleep masks. “It's going to be a combination of things that they need to try.”

Let Them Know What to Expect

Caution patients that they will have to continue treatment for their dry eye after surgery. Dr. Trattler notes that ocular surface dryness is usually a chronic problem rather than an acute one. While continued lid hygiene may be enough to keep the disease in check, patients may also need Tobradex ST on an intermittent basis, he says.

Dr. Trattler will also prescribe Lotemax for use along the lid margins in cases of acute exacerbation. “If necessary, on a more chronic basis I prescribe Azasite, to be used usually twice a day on alternating months — on a month, off a month. That is usually enough to hold the disease process in check.”

Preservative-free artificial tears or tears specially designed for patients with MGD, used on a chronic basis, are helpful as well, Dr. Trattler says.

Dr. Ashrafzadeh agrees that continuation of therapy is imperative. He frequently finds that his dry eye patients need a course of oral minocycline for several months after cataract surgery. “If we consider a course of azithromycin, they tend to be on it for six-plus months of chronic therapy,” he explains.

According to Dr. Raju, most patients will accept the idea of continued therapy for dry eye, but it does help with patient compliance and morale if you explain to them at the outset that there are a few different options available to help them, and that as their physician, you are going to work with them until the right treatment for them is found. “I tell my patients that I want them to have the best possible benefit from that lens, and if that means spending a little more time making sure they have as optimal a surface as possible, that it will be well worth it,” Dr. Raju says. “They need to understand the why, and that it is for their benefit.” OM

References

1. Prospective Health Assessment of Cataract Patients' Ocular Surface.
2. Donnenfeld ED, Holland EJ, Solomon KD, Fiore J, Gobbo A, Prince J et al. A multicenter randomized controlled fellow eye trial of pulse-dosed difluprednate 0.05% vs prednisolone acetate 1% in cataract surgery. AJO. Oct. 2011.152(4):609-617.
3. Budman KA, Chun AG, Markowitz B. Comparison of the incidence of dry eye complaints in a contact lens wearing population undergoing laser refractive surgery with and without preoperative punctal occlusion. Presented at: 2012 Annual Meeting of the Association for Research in Vision and Ophthalmology. Fort Lauderdale, FL. May 6-10, 2012.