PREPARING the Ocular Surface for Surgery

Quality vision outcomes and patient satisfaction depend on it.

By Desiree Ifft, Contributing Editor

Screening for and treating ocular surface disease (OSD) in all patients who will undergo anterior segment surgery is increasingly standard procedure among leading ophthalmologists. Based on their own experience and evidence that has been mounting for quite some time, they have no doubt that untreated preexisting dry eye jeopardizes vision outcomes for not only corneal refractive surgery patients, but cataract surgery patients as well.^1-6 They also have every indication that OSD is more common in surgical populations than previously believed, is often present without symptoms and may require continued therapy postoperatively to maintain initial outcomes.^1-6 Both aqueous-deficient and evaporative dry eye, the latter usually caused by meibomian gland dysfunction (MGD), disrupt the ocular surface and tear film, destabilizing an important component in the optical performance of the eye. “We can attempt to fix the visual system with cataract or refractive surgery, but if the ocular surface is poor, outcomes suffer,” says William Trattler, MD, Center for Excellence in Eye Care, Miami, Fla. “Without a healthy, stable tear film and a smooth epithelial surface, patients will perceive their results as poor.”

OSD begins to cause problems long before the patient is wheeled into the OR or under the laser. “It can throw off your preoperative data significantly,” explains Marguerite McDonald, MD, FACS, Ophthalmic Consultants of Long Island, New York. For laser vision correction, dry eye can cause wavefront measurements to be incorrect. In dry eyes, higher-order aberrations are 2.5 times greater than in normal eyes.⁷ For cataract surgery, OSD interferes with keratometry and topography, compromising IOL power calculation and the accuracy of the measured axis and magnitude of astigmatism. Postoperatively, it delays healing and causes vision to fluctuate. “With any IOL, dry eye can diminish quality of vision, and untreated OSD is a primary reason patients may be unhappy with multifocal lenses and ask for them to be explanted,” Dr. McDonald says. “Think of it this way: If you tell people they have dry eye before surgery, it’s their problem. If you tell them afterward, it’s your problem.”

Put Testing Protocols in Place

Dr. McDonald and Dr. Trattler screen all of their corneal refractive and cataract surgery patients for OSD, regardless of their age. They treat the signs until they’re convinced dry eye and/or MGD won’t skew the preoperative measurements before moving ahead with the procedure.

“Today, we have more methods than ever to help us assess OSD,” Dr. Trattler says. “We can use point-of-care testing such as the TearLab Osmolarity System (TearLab) or InflammaDry (RPS), and the standard tests that have been in use for decades, such as tear break-up time (TBUT) and corneal staining, are still valuable. I also look at the symmetry of the IOLMaster (Carl Zeiss Meditec) keratometry readings, as this device takes three consecutive measurements. If they show different results for the power and axis of astigmatism, rapid TBUT is a likely cause. Finally, topography is an excellent tool for diagnosing a poor quality tear film. Topography maps for patients with OSD vary from the typical pattern. Steepness may fluctuate in localized areas and there may be areas of dropout.”

To determine the incidence of preoperative corneal abnormalities that could affect final visual results, Dr. Trattler and colleagues recently conducted a chart review of 400 eyes of 200 consecutive patients who were undergoing cataract surgery and had undergone topography for both eyes.⁸ Excluding patients with a history of previous corneal surgery, they found approximately 25% of eyes had abnormal corneal topography that was consistent with either forme fruste keratoconus (FFK) (1.6%), pellucid marginal degeneration (PMD) (1.4%), keratoconus (3.0%) and borderline FFK, PMD or superior steepening (9.2%). The most common reason for abnormal topography (9.5%) was irregular astigmatism consistent with dry eye. “It is very useful to perform topography on all cataract surgery patients so we can anticipate potential problems, plan surgery accordingly and set appropriate patient expectations,” Dr. Trattler notes. “When the abnormality revealed is dry eye, we can usually address it rather than excluding patients from receiving a toric or presbyopia-correcting IOL when they really are candidates.”

Dr. McDonald’s attention to OSD in potential surgery patients begins with having them complete a short symptoms questionnaire, similar to the SPEED questionnaire published in Cornea.⁹ The checklist takes patients little more than a minute to complete. She also uses the TearLab osmolarity test, which has been shown to be the single best marker of dry eye disease severity across normal, mild to moderate and severe categories.¹⁰ (In the interest of patient flow and efficiency, her technicians have a standing order to perform the test for any patient who checks off at least one symptom on the questionnaire.) The InflammaDry test to detect matrix metalloproteinase-(MMP-9), which is elevated in dry eye,¹¹ is also performed as part of the workup. “If a patient has low tear osmolarity but an elevated MMP-9 level, I know there’s something other than dry eye causing inflammation,” Dr. McDonald says. “I look then for frequently overlooked conditions such as lagophthalmos, conjunctivochalasis or epithelial basement membrane dystrophy.”

FIGURE 1. Ocular surface disease, as indicated by patchy corneal staining, is a likely cause of this pseudophakic patient’s dissatisfaction with postoperative vision.
Image courtesy of William Trattler, MD

At the slit lamp, Dr. McDonald checks the tear meniscus and TBUT, expresses the meibomian glands to evaluate the quality of the meibum and uses lissamine green if necessary to help complete the picture of the ocular surface status. In addition, she finds the Oculus Keratograph 5M to be a “phenomenal tool.” A corneal topographer, the Keratograph 5M is also equipped with several functions for dry eye/tear film evaluation, including non-invasive TBUT, automated tear meniscus height measurement, lipid layer thickness, meibography of the upper and lower eye lids, 3D visualization of the meibomian glands and automatic detection and classification of bulbar redness. “The instrument can also track the movement of particulate matter in the tear film; their velocity and direction is directly related to tear film viscosity,” Dr. McDonald explains. “For example, rapid movement after blinking indicates a thinner tear film with less viscosity.”

Figures 2 and 3. Lissamine green staining and the Schirmer’s test continue to be useful tools in the assessment of dry eye.
Images courtesy of William Trattler, MD

In Dr. McDonald’s practice, the Sjö test (Nicox) for Sjögren’s Syndrome is also utilized. “I test everyone with an unusual demographic, such as young patients with dry eye or people who have dry eye that is resistant or responding poorly to treatment,” she explains. “A significant number of dry eye patients have Sjögren’s, and their dry eye tends to require more aggressive treatment. It’s very important as well to send patients who test positive to a rheumatologist who can monitor them for the development of lymphoma, for which they’re at higher risk, and encourage them to see other providers, such as periodontists, to help them manage the wide range of effects of the disease.”

Dr. McDonald is in the process of adding the Doctor’s Allergy Formula (DAF) diagnostic system (Doctor’s Allergy Formula) to her diagnostic template. DAF, an in-office, no-needle skin test, determines the source of a patient’s ocular allergies. The test is regionalized with panels that include botanicals specific to each area of the country. “Dry eye and ocular allergy are independent issues, but one aggravates the other,” she says. “Dry eyes can’t wash out the pollen, which means the pollen has more contact time on the eye. And of course both can cause itching. We need to quiet the ocular surface before surgery. This test will be another helpful tool for sorting out what is happening on the ocular surface and guiding treatment.”

Tailor the Treatment Plan

For patients with OSD, a treatment plan can be tailored to stabilize the ocular surface prior to capture of the preoperative measurements required for cataract or refractive surgery. Dr. McDonald takes a stepwise approach based on each patient’s osmolarity test score If MGD is a contributing factor, she structures the treatment plan accordingly. For patients with a tear osmolarity score of 290-316 mOsmol/L, Dr. McDonald recommends:

• a quality brand of preserved artificial tears qid. Her preference is FreshKote (FOCUS Laboratories), which was until very recently a prescription tear covered by most if not all insurance plans. “It just went off prescription, but most pharmacies don’t know this yet, so we’re still giving our patients prescriptions for it,” Dr. McDonald says.

• an Omega-3 supplement. She prefers Tozal (FOCUS Laboratories), which is by prescription only and designed for patients who have or are at risk for dry eye, MGD or age-related macular degeneration. “NASA developed this formula for the astronauts in the space station, and it has been updated to reflect the findings of AREDS II,” she says. “These are the smallest softgels in the industry, which patients appreciate.”

For patients with a tear osmolarity score of 317 mOsmol/L or higher, Dr. McDonald adds to the regimen:

• cyclosporine ophthalmic emulsion (Restasis, Allergan) bid

• induction therapy with loteprednol etabonate ophthalmic gel (Lotemax, Bausch + Lomb), qid for 2 weeks then bid for 2 weeks. She finds the loteprednol provides immediate relief for symptomatic patients (cyclosporine emulsion takes at least a month to start providing results), and prevents the stinging they may feel with the first month of cyclosporine therapy.

Patients with a tear osmolarity score of 325 mOsmol/L or higher receive all of the above treatments but are advised to use preservative-free tears, rather than preserved tears, and to use them eight times per day or more if desired. When signs and symptoms classify as level 4 severity as defined by the International Dry Eye Workshop (DEWS), autologous serum can be very helpful, “relatively costly, but incredibly effective,” Dr. McDonald says.

MGD plays a role in most cases of dry eye and should therefore be specifically addressed when it is present with DEWS level 2 and higher dry eye. At level 2, Dr. McDonald has patients use:

• hot soaks twice a day followed immediately by

• Ocusoft lid scrubs and pads twice a day.

At level 3 and 4 dry eye with MGD, she prescribes:

• azithromycin drops (AzaSite, Akorn) bid (rubbed into the lid margins immediately after the hot soaks and scrub). If the patient has very dry eyes as well, which is often the case, she may prescribe erythromycin ointment in place of AzaSite, to be used just once daily, at night. Patients are instructed to reapply it if they get up in the middle of the night. “The ointment isn’t quite as effective as AzaSite, yet still very effective, and it’s inexpensive, covered by every insurance, and will drive massive amounts of moisture into the ocular tissues while treating the MGD,” Dr. McDonald says.

• 50 mg per day of oral doxycycline. “Doxycycline is magical as an anti-inflammatory agent for the skin,” Dr. McDonald says, noting that she keeps some patients on the medication after surgery for 6 to 12 months. “Some patients can go through one course and be fine, but they may need to go back on for the occasional flare-up. For others, we discontinue the doxycycline after 6 to 12 months but they become immediately more symptomatic and must go right back on.”

In cases where a patient’s MGD is under control but symptoms persist, Dr. McDonald may insert punctal plugs. “It’s very important that the MGD is under control first,” she cautions. She considers offering patients the LipiFlow treatment (TearScience) for level 2 and above dry eye with MGD if the patients are improved but still symptomatic on the regimen, or if patients aren’t willing or able to comply.

Well Worth the Effort

The first goal of treating OSD in surgical patients is to ensure the ocular surface is stable enough to allow accurate pre-op measurements. For many patients, treatment is continued postoperatively so quality vision is maintained. “Patients and surgeons share the same goal of achieving a positive result, but patients usually are eager to get their surgery scheduled,” Dr. Trattler says. “We schedule their procedures for 4 to 6 weeks from the time of their evaluation so they feel the process is moving forward, and we have time to address their OSD. In the majority of cases, the eye is in good shape for the pre-op measurements after 1 to 2 weeks of treatment.”

Dr. McDonald finds she rarely needs to delay a surgery for more than a month because of dry eye, even given the severe cases she often sees in her practice. “Patients tend to comply with the treatment recommendations for that amount of time when they understand our goal,” she says. “In about 5% of cases, I may want them to continue treatment, maybe continuing the Lotemax for another month before having them back for biometry. For the sake of pre-op numbers and post-op patient satisfaction, it’s extremely important to address OSD prior to surgery. Surgeons may worry that putting a focus on dry eye in their practice would lead to a decrease in procedure volume, but I’ve found the opposite to be true. I have never lost a patient by saying ‘We’re going to delay surgery for a month while we treat you, so the IOL measurements will be accurate.’ And the older dry eye patients who will gravitate to your dry eye center of excellence are very grateful and loyal. When you take care of unhappy dry eye patients on a regular basis, they want to stay with you when it’s time for surgery.” ■

References