Avoiding dry eye

Dry eye is one of the most common complications of corneal refractive surgery, with careful preoperative evaluation needed to identify patients with active dry eye disease who should not undergo surgery, according to François Malecaze MD. “Prevention is always better than cure. Dry eye can have an impact on the surgery in terms of safety, patient satisfaction and outcome, so we need rigorous preoperative screening of high-risk patients and specific postoperative care,” he told delegates attending the European Society of Ophthalmology (SOE) Congress in Barcelona. The incidence of dry eye following refractive surgery ranges from 5% to 30% in the scientific literature, said Dr Malecaze. “There is a large variability between the studies depending on the diagnosis criteria of dry eye, the study protocol used in terms of inclusion criteria, patient characteristics and type of surgery, and also the follow-up period,” he said. Dry eye after refractive surgery is an important issue because of its potential impact on the outcomes, said Dr Malecaze. “There is a real safety concern with severe dry eye disease in 0.05% of cases. The consequences after surgery are a decline in satisfaction in terms of symptoms and vision quality and a decrease in refractive predictability,” he said. While there are multiple theories as to how LASIK contributes to dry eyes, the main proposed cause is iatrogenic corneal nerve damage, noted Dr Malecaze, as LASIK disrupts the dense sub-basal nerve plexus and stromal corneal nerves. Identifying patients at risk for severe dry eye is important to optimise surgical outcomes, said Dr Malecaze. There are several diseases that are more likely to increase the risk of dry eye that need to be diagnosed before corneal refractive surgery, such as Sjögren’s syndrome, diabetes mellitus, patients undergoing treatment for acne and so on. The type of surgery also has a bearing on healing response, said Dr Malecaze. One study showed that corneal sub-basal nerve density does not recover as well after LASIK, compared to photorefractive keratectomy. While some studies suggest that small-incision lenticule extraction may result in less nerve damage and may better preserve corneal sensitivity, further controlled studies are necessary to evaluate the real clinical impact, said Dr Malecaze. He said it was vital to treat contributing factors prior to surgery, and during the first three months afterwards to reassure the patient using tear substitutes and gels systematically, reducing the use of preserved eye drops. François Malecaze: malecaze.fr@chu-toulouse.fr