Eyeworld

EW FEATURE 64 Glaucoma and the cataract patient • February 2017 corneal surface, and tear osmolarity. "The most important thing is adding one drop at a time," she said. If the patient has a very high pressure, you may have to add more than one. By adding one at a time, you can see what the corneal surface does, Dr. Weissman said. If there is more dryness after one, switch to preservative-free, she suggested. It's also important to make sure the patient is lubricating the eyes frequently with preservative-free artificial tears. Topography is important to have readily available to look for distortion on the corneal surface, Dr. Weissman said. Staining is also helpful to see if there's keratopathy on the exam that can show how dry the eyes are. Dr. Weissman added that serum tears are a useful option. With these, the patient's blood is drawn, spun down, and teardrops are formulat- ed from the blood. They have an anti-inflammatory effect and can be helpful in patients with both glauco- ma and severe dry eye, she said. Impact of OSD on astigmatism measurements There may be a concern that ocular surface problems can make astigma- tism measurements less accurate in glaucoma patients. Dr. Wallace said that in order to get the best visual outcomes after cataract surgery, she brings the patient back in for IOL calculations on a separate preop visit where measurements are performed before any drops are placed in the eye. "We also may start a prescrip- tion medicine to treat the dry eye about a month before surgery," she said. Dr. Weissman uses topography to help account for these potentially inaccurate measurements, as it helps her to evaluate the patient better. EW Editors' note: Dr. Kammer has finan- cial interests with Allergan (Dublin, Ireland). Dr. Realini has financial interests with Allergan, Bausch + Lomb (Bridgewater, New Jersey), and Alcon (Fort Worth, Texas). Dr. Wallace has financial interests with Allergan. Dr. Weissman has no financial interests related to her comments. Contact information Kammer: jeff.kammer@vanderbilt.edu Realini: hypotony@gmail.com Wallace: danajwallace@gmail.com Weissman: heather.m.weissman@gmail.com Dr. Kammer stressed the need for early use SLT, which can produce a drop in IOP that is comparable to pharmacologic treatment while avoiding the preservative-induced toxicity to the ocular surface. "I also consider using oral car- bonic anhydrase inhibitors (CAIs) in selected individuals," he said. "This is a bit controversial because oral CAIs have been documented to occasionally exacerbate dry eyes, particularly in elderly patients, whose body water content is lower compared to younger individuals." However, for younger patients, those with significant sensitivity or intol- erance to preservatives, and those who don't have the dexterity to instill eye drops, this is a reasonable option, he said. "In many individ- uals, the benefits of a reduced BAK load outweigh the mild dehydration caused by the oral CAI." Another option, Dr. Kammer said, is to use eye drops that are ei- ther preservative-free or utilize non- BAK preservatives. From a clinical perspective, the glaucoma medica- tions that use less toxic preservatives are well tolerated and often result in an improvement in symptomatolo- gy, particularly if these patients have pre-existing ocular surface issues, he said. Another way to minimize the BAK burden is to use a preserva- tive-free formulation. "Due to the significant risk for contamination in multidose bottles, the only practi- cal way to accomplish this is with the use of single-dose units," Dr. Kammer said. "While the lack of any irritating preservative is a boon for patients, this option tends to be much more expensive, and some pa- tients (particularly the elderly) have difficulty handling the small vials." Many patients will be fine with preserved glaucoma medications. But a certain segment of the pop- ulation benefits particularly from minimizing BAK exposure including those with a pre-existing dry eye or ocular surface disease; a documented intolerance to preservatives; an ex- isting multidrug treatment regimen; and treatment that is expected to last many years. Tests to perform Dr. Weissman said many of the tests used for dry eye disease are import- ant for these patients as well, includ- ing tear break-up time, Schirmer's test, topography looking at the OSD and glaucoma. "While steroids can be beneficial, they have the chance of increasing IOP, which is counterproductive for glaucoma patients," he said. "If they need to be used, I would only recommend using loteprednol BID for a week or two, as a bridge to one of the immunomodulatory agents." Mean- while, punctal plugs help maintain lubrication, but they also keep any preservative around longer and can potentiate the negative effects of the BAK on the ocular surface, Dr. Kammer said. The second goal in patients with both OSD and glaucoma is to reduce exposure to preservatives, and there are several strategies to do this. First, Dr. Kammer said to reduce the total number of drops. "This can be achieved by preferentially pre- scribing glaucoma drops that can be dosed once daily, like beta blockers and prostaglandin analogues," he said. The use of fixed-combination preparations can also be increased. "There is strong clinical data that suggests that fixed combination glaucoma drops have a better safety profile and tolerability compared to when the medications are used separately," he said. Treating continued from page 63

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