Before refractive or cataract surgery

Diseases of the corneal surface are not just the purview of the specialist anymore. These can also have an important impact on cataract and refractive surgery cases if left untreated. As a result, more and more surgeons who are primarily performing procedures like phacoemulsification or LASIK are beginning to keep a watchful eye on the cornea as well. We asked some leading practitioners how corneal disease can crop up and affect outcomes in cases that otherwise would likely be run-of-the-mill.

Bemoaning blepharitis

One case recently referred to the University of Minnesota, involved an elderly patient from a veteran’s hospital who had significant blepharitis that wasn’t treated prior to cataract surgery, according to Gary S. Schwartz, M.D., adjunct associate professor, University of Minnesota, Stillwater, Minn. “The patient had cataract surgery, had a lot of epithelial keratopathy after surgery and was treated by the resident,” Dr. Schwartz said. “But because he had discomfort and ocular surface problems they put him on topical nonsteroidals and after a week of that he ended up with significant keratitis.” He ended up with a corneal scar and ultimately with vision loss. “It’s a lesson that topical, non-steroidal anti-inflammatory drugs have to be used sparingly and judiciously in patients with significant ocular surface disease,” Dr. Schwartz said.
The patient’s untreated posterior blepharitis set him up for trouble. Dr. Schwartz sees this as really a meibomium gland dysfunction. “This is something that realistically we all get as we get older,” he said. While normally the oils that the meibomium glands excrete are thin at body temperature, when this mechanism goes array the oil becomes very viscous. As a result, it can take a long time to make its way through the meibomium gland which is 0.5 centimeter in the lower lid and 1 centimeter in the upper lid. “In a normal person it takes just a few days, but in someone who has had meibomium gland disease it can take weeks for the oil to make its way through the glands,” Dr. Schwartz said. “It takes so long that the oils become toxic.” The oil can become loaded with bacteria and also get broken down into soap. Dr. Schwartz likens the difference between the normal and diseased oil to water in a babbling brook versus that in a standing pond.
“Every time the patient blinks they just dump this feted stuff on the surface of the eye,” Dr. Schwartz said. The fact is that cataract surgery, with the need for a lid speculum to keep the eye open for a time, and all of the ensuing drops and numbing medications can take a patient who is gingerly balanced on the fence and knock him right off.
A patient such as the veteran mentioned here should have been treated aggressively prior to surgery. Dr. Schwartz recommends that such patients be treated with artificial tears and put on oral supplements such as fish and flax seed oil. “Your really have to get that done prior to surgery because it’s just so much more difficult and dangerous to treat afterwards,” he said.

Eroding LASIK confidence

Another all too common corneal disease scenario involves recurrent erosions that go unnoted prior to LASIK surgery, according to Stephen C. Pflugfelder, M.D., professor of ophthalmology, Baylor College of Medicine, Houston. Consider the case of a 40-year-old woman, with mild rosacea, who underwent bilateral LASIK a few years ago for myopia. At the time of the LASIK she had a small epithelial defect in her left eye, which healed without a problem. Then the woman recently scratched the eye again with her fingernail. It healed in several days without a problem. However, one month after the injury she awoke in the middle of the night with severe pain in the left eye accompanied by profuse tearing.
The next morning she continued to have pain and slightly blurred vision so she went to her ophthalmologist who noted that she had a corneal epithelial defect. This was treated initially with artificial tears, a topical antibiotic and a bandaged contact lens. The patient’s comfort improved and the epithelial defect healed within two days. Two weeks later she awoke again in the middle of the night with a similar pain in the eye and she again saw her ophthalmologist who noticed another epithelial erosion in the same location as the earlier epithelial defect. She was placed on topical steroid drop and oral doxycycline 50 milligrams twice daily. The recurrent erosion healed within a day, the steroid was tapered over one week, and she was continued on oral doxycycline for one month and has remained asymptomatic since then.
The patient here had several predisposing risk factors including the refractive surgery itself, according to Dr. Pflugfelder. “Many patients that had LASIK, particularly when the blade microkeratomes were being used, would experience some minor trauma to the epithelium,” he said. “Now as she approaches into her forties she’s probably starting to get dry eye—that in addition to the fingernail injury are also considered risk factors for recurrent erosion.” In addition, the patient’s rosacea is another predisposing factor. “Up to 10 to 15% of patients with rosacea have recurrent erosions,” Dr. Pflugfelder said.
For cases in which practitioners notice epithelial basement membrane disease prior to LASIK this can be a tip-off that the patient is at risk for recurrent erosions. “The recommendation is to either scrape it before the LASIK or to use surface ablation because you can get rid of the epithelium and the problem all at one time,” Dr. Pflugfelder said. “If there is rosacea then the patient should be treated preoperatively with a steroid and an oral doxycyline.”
While some patients can still do reasonably well healing up within a few days of LASIK never to revisit the problem if this is left untreated others do extremely poorly. “If there is a big erosion at the time of surgery it’s a risk factor for getting DLK (diffuse lamellar keratitis),” Dr. Pflugfelder said. “This could be quite severe lasting for a week or two and once the patient heals there may be more irregularity of the surface or interface haze and then they may get multiple recurrent erosions.”
Recurrent erosions can also happen after uneventful phacoemulsification. This can occur when the doctor is even simply irrigating the surface with saline at the time of surgery, which could cause the epithelium to loosen, Dr. Pflugfelder warns. “The doctor should have a high index of suspicion because it’s always easy even when you know about it to just say, ‘Well, it’s probably going to be OK it’s just a little area of basement membrane disease,’” he said. He finds that it’s too easy to get burned that way. “Doctors who refer me patients say the same thing—‘I wish that I had taken care of it ahead of time,’” he said. “The wisdom is to try to address it before hand and you’ll save yourself a lot of aggravation and the patient will be a lot happier.”

Salzmann’s nodule degeneration on the map

One cataract case that Edward J. Holland, M. D., professor of ophthalmology, University of Cincinnati, and director, Cornea Service, Cincinnati Eye Institute, Cincinnati, recently dealt with, involved a patient with Salzmann’s nodule degeneration who had very abnormal topography. “This patient had high astigmatism and decreased vision due to the astigmatism and the cataract,” Dr. Holland said. To treat the patient Dr. Holland first went after the Salzmann’s nodule. He removed the nodule and let the cornea fully heal. Only then did he decide to take the cataract out. Of note, at this point he found that there was no longer any astigmatism with which to deal.
Such Salzmann’s nodule degeneration is usually associated with chronic ocular surface inflammation, putting patients with blepharitis or, dry eye disease at increased risk. Gender can also be a predisposing factor. “About 95% of patients are women, so there may be some hormonal influence that we don’t know about,” Dr. Holland said. “In addition, long-term contact lens wearing increases your risk of nodule formation.”
Unfortunately, clinicians do not always spot these preoperatively. “We’re trained to look quickly at the cornea stroma with a narrow slit beam of light,” Dr. Holland said. “Really if we were to have one look at the cornea it should be with a broad oblique view on low magnification to see the entire cornea.”
Some of the areas of Salzmann’s nodule degeneration can also be very subtle and there can be sub-epithelial fibrosis. Dr. Holland warns that you can miss these unless you examine the cornea with the right type of light. In addition, since these can be under the upper lid he recommends using a cotton tip applicator to raise this and take a good look underneath. “If you don’t raise the lid you miss the superior 1/3 of the cornea,” Dr. Holland said. “You can miss a nodule which may be inducing astigmatism.”
If this condition is not caught before cataract surgery it can result in secondarily induced astigmatism. “You may do some astigmatism correction when you really should be taking off the nodule, instead of secondary astigmatism management,” Dr. Holland said. “This may also throw off your IOL calculations.” He finds that most often it can reduce the patients’ vision either if the nodule is in the visual axis or, if it’s an elevated one and results in abnormal tear flow. “So, due to a variety of things nodules can reduce your visual acuity,” he said.
When it is properly detected Salzmann’s nodules can be treated with a superficial keratectomy. Dr. Holland recommends scraping the epithelium and then finding the lamellar plane that is at the depth of the protuberance, grabbing this nodule and then slowly dissecting it with a scalpel or, peeling it off in the lamellar plane. For cases where patients complain of significant haze, phototherapeutic keratectomy (PTK) may be recommended, especially if the nodule is in the visual axis. “The other more recent treatment that we’ve added to the management is that if the patient has had a return of the nodules we have been using mitomycin C (MMC) right after removal and have found that this has reduced our recurrence rate,” Dr. Holland said.
Overall, Dr. Holland thinks that practitioners are now becoming more aware of the importance of the ocular surface in optimizing cataract and refractive results. “Probably the most common problem with quality of vision after cataract and refractive surgery is the health of the ocular surface,” he said. “So, as we become better clinicians we’re getting better outcomes.” Dr. Holland thinks that it’s important to take a careful look at the cornea preoperatively. “We may actually in patients with significant ocular surface disease recommend therapy and delay surgery to get a better outcome,” he said. “This is something which wasn’t done often before, but which is done more commonly now because we want to get the patient’s ocular surface health back before we undertake any surgical intervention.”

Editors’ note: Drs. Schwartz and Pflugfelder have no financial interests related to their comments. Dr. Holland has financial interests with Alcon (Fort Worth, Texas), Bausch and Lomb (Rochester, N.Y.), and Allergan (Irvine, Calif.), among other companies.

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