Eyeworld

EW FEATURE 56 Phaco and corneal comorbidities September 2014 by Ellen Stodola EyeWorld Staff Writer When doing measurements at the level of the cornea, a mistake can cause errors in the IOL power. Mistakes are easy to make if you have an irregular tear film, Dr. Hovanesian said. Especially with multifocal lenses, it is important to distinguish between good and bad candidates because multifocal lenses already have one source that degrades contrast. Dr. Thompson said that dry eye is one condition that would need to be treated before cataract surgery. "When I approach a dry eye patient, I try to determine whether they are an aqueous deficient dry eye patient or an evaporative dry eye patient," he said. There are a number of risk factors, conditions, and medications that go along with these. "Either way, the end result is an unstable tear film and can lead to changes in keratometry readings and inaccuracy of keratometry readings," Dr. Thompson said. "The most important thing is being accurate," Dr. Ketcherside said. "People aren't going to be happy if you put in the wrong lens or the wrong power lens or you don't deliver on what you say you're going to do." Preferred regimen Dr. Hovanesian said it is important to be vigilant for signs of potential problems before counseling the pa- tient. "What we're concerned about largely is the biometry," he said. Sometimes the fastest way to tune up the ocular surface is to put a patient on steroids short term. Dr. Hovanesian said that he uses Lotemax gel (loteprednol, Bausch + Lomb, Bridgewater, N.J.) for this, but any steroid would be helpful. Loteprednol is good, he said, because it is kind to the ocular surface and is potent but not likely to produce pressure spikes. "I'll do it for a week before they go through measure- ments, and that seems to make a big difference," he said. Dr. Ketcherside said his pre- ferred regimen varies depending on the patient and severity of problems. For mild cases, he may choose some- thing as simple as having patients use artificial tears for 2 weeks and come back to repeat testing. Treating corneal issues ahead of time can help surgeons complete a more successful cataract surgery W ith patients set to undergo cataract surgery, it is import- ant for surgeons to identify any pre- existing conditions. Corneal comorbidities, including dry eye, blepharitis, and epithelial irreg- ularities, are important to address. John Hovanesian, MD, Harvard Eye Associates, Laguna Hills, Calif.; Christopher Ketcherside, MD, Kansas City Eye Clinic, Overland Park, Kan.; and Charles Thompson, MD, The Eye Clinic, Lake Charles, La., discussed how they approach these patients. Why treat before cataract surgery? "Whether we're using a premium lens, doing refractive cataract surgery, or just basic correction of cataract, patients have come to expect that they're going to have a high level of vision and in many cases spectacle-free vision after sur- gery," Dr. Hovanesian said. "We're simply not going to achieve that if we have a tear film or an epithelial or corneal problem." AT A GLANCE • Irregular tear film and epithelial defects can affect the accuracy of measurements taken at the level of the cornea. • Patients with these problems may need to be treated and wait anywhere from a week to several months before repeating calculations and undergoing cataract surgery. • Anterior basement membrane dystrophy (ABMD), pterygium, Salzmann's, blepharitis, and dry eye are among some of the conditions that surgeons may look for before proceeding with cataract surgery. Cataract surgery with corneal comorbidities For moderate disease, he may start the patient on Restasis (cyc- losporine, Allergan, Irvine, Calif.), steroids, and artificial tears, and then try again in a month. If a patient has significant blepharitis issues, he will start with heat and lid hygiene and choose other treatments like doxycycline, AzaSite (azithromycin, Akorn, Lake Forest, Ill.), steroids, and omega-3s as necessary. Dr. Thompson said that he goes through treatments of dry eye based on what category of condition the patient falls into. "Lid hygiene becomes very important because a lot of patients who are dry, not only do they miss the aqueous component of their tear film, but they also miss the antibacterial effect of their tears," he said. When patients are dry, that leads to anterior blepharitis and a lot of bacteria on the lids, Dr. Thompson said. His approach is to use replacement tears to clean the lids so there is a good quality of tears around the eye. He then moves relatively quickly to punctal plugs and Restasis. Dr. Thompson said it is helpful to have technologies like the test from TearLab (San Diego) to check osmolarity to ensure that treatment is moving in the right direction. He would also use the Schirmer's test and lissamine green stain to see how the treatment is affecting the ocular surface. For dry eye patients with mei- bomian gland dysfunction, there is an emphasis on lid hygiene. Using warm compresses and doing lid massages help with this condition, as does using lid wipes that promote meibomian gland function. Systemic medicine like doxycycline and the topical version of azithromycin can help as well. "Once I feel like the patient's comfort has improved and the test- ing has improved, I will usually go on with preoperative testing for cat- aract surgery," Dr. Thompson said. When it comes to pretreating cataract patients with blepharitis, there are a number of options. With typical anterior blepharitis, erythro- mycin eyelid scrub once a night and a warm compress in the morning for about 3 weeks are options, he said. If the patient is unresponsive to that, Dr. Thompson uses BlephEx (Rysurg, Palm Beach, Fla.), which is a way to clean the lids in the office and only takes about 5 to 10 minutes. "It's been very useful in treating blepharitis patients preoper- atively from a cataract standpoint or from a corneal surgery standpoint," Dr. Thompson said. Untreated ocular surface disease, such as in this patient with advanced aqueous tear deficiency, reduces the accuracy of preoperative IOL measurements. Source: John A. Hovanesian, MD

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