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Tips and techniquess for cataract and refractive success: The dry eye connection.
Dry eye disease and cataract and refractive surgery are intertwined closely. Pre-existing dry eye can affect surgical outcomes and, in severe cases, is a contraindication for surgery, whereas surgery causes trauma to the ocular surface and may lead to signs and symptoms of dry eye. To break this cycle, a two-pronged approach of treating dry eye before surgery and taking steps to prevent its development postoperatively is advisable.
Dry eye is believed to be one of the most commonly diagnosed ocular conditions in the US and is particularly frequent among older women. It is likely, though, that many people who suffer from dry eye have never been diagnosed by an eye-care professional, and prevalence may be grossly underestimated. Various estimates place the number of sufferers at 20 to 55 million.
Regardless of the true prevalence, the numbers are unquestionably high, and preoperative screening is a sound strategy, said Marguerite McDonald, MD, clinical professor of ophthalmology at New York University of Medicine, New York, and also at Tulane University Health Sciences Centre, New Orleans.
Another speaker explained that while advanced technology has improved safety and visual quality for cataract and refractive surgery, there is a downside as well. Edward J. Holland, MD, professor of ophthalmology at the University of Cincinnati and director of Cornea Services at the Cincinnati Eye Institute, said that disruption of the ocular surface induces distortion, which is magnified by a multifocal IOL. The most common source of decreased visual acuity and dissatisfaction among patients who have been implanted with a premium lens is ocular surface disease, he added.
Cataract surgery causes trauma to the corneal nerves by cutting these nerves at the limbus; the phaco incision, paracentesis, and relaxing incisions add to the trauma, Dr. Holland said. To reduce the severity of postsurgical dry eye, he recommended that appropriate preventive measures be taken at several time points. Preoperatively, patients at risk of dry eye should be identified and treatment offered to maximize tear film stability. Dr. Holland suggested that it is preferable to disappoint a patient by delaying surgery for a short time than to face the consequences of significant postoperative problems such as fluctuating vision that impairs visual acuity for several months.
Intraoperatively, dry eye promoters should be minimized and the epithelium protected. Postoperatively, therapeutic intervention should be applied.
The symptoms of dry eye vary and may include tearing, discomfort, dryness, burning, stinging, irritation, blurry vision, a gritty feeling or stickiness, itching, photophobia or redness. These symptoms may not correlate with the clinical signs, which increase the difficulty of making an accurate diagnosis, said Eric D. Donnenfeld, MD, a partner in Ophthalmic Consultants of Long Island and a clinical professor of ophthalmology at New York University.
The most useful symptom for diagnosing ocular surface disease, however, is fluctuating vision, Dr Donnenfeld said. This fluctuation includes vision changes between blinks, at different times of the day, and after prolonged effort.
Clinicians also can gain clues by observing their patients and studying their history. Older patients and perimenopausal and postmenopausal women, for example, are at higher risk, as are cigarette-smokers, patients who wear contact lenses, have an autoimmune disease or have had cosmetic eyelid surgery.
Corneal staining with lissamine green also is beneficial and tends to be an accurate diagnostic tool, Dr Donnenfeld added.
Stephen C. Pflugfelder, MD, also emphasized the importance of a healthy, stable tear film as an essential component for high-quality visual function. To this end, physicians should identify and treat patients with dry eye and corneal epithelial disease preoperatively.
This continuing medical education activity was jointly sponsored by the New York Eye and Ear Infirmary and cme² in partnership with Ophthalmology Times, and was supported through an unrestricted educational grant from Allergan.