Neuropathy after refractive surgery

Corneal neuropathic pain is a rare but potentially devastating complication arising from trauma and the abnormal healing of corneal nerves after laser refractive surgery. It differs from classic post-LASIK dry eye in the severity and duration of symptoms and can lead to depression and suicidal impulses in some patients, according to Vincent Borderie MD, PhD. “Corneal neuropathy is a leading cause of patient complaints after corneal refractive surgery. Prevention is always better than cure, so we really need to provide patients with very precise, preoperative information. We should always assess corneal sensation before refractive surgery and to avoid corneal refractive surgery in eyes with impaired corneal sensation,” Dr Borderie said at the joint ESCRS-EuCornea symposium held during the 38th Congress of the ESCRS. Dr Borderie, in practice at the Quinze-Vingts Hospital in Paris, France, cited the case of a 34-year-old male patient to highlight the difficulty of diagnosing and treating corneal neuropathy. The patient had myopic astigmatism and had undergone LASIK surgery in 2012. In 2013, he was referred to Dr Borderie’s service complaining of sensations of dryness, stinging and burning, as well as blurred vision. “He was suffering from depression as a result of his chronic symptoms and had experienced no improvement with commercially available tear substitutes. However, his vision was pretty good, with uncorrected distance visual acuity of 20/20 in both eyes with moderate residual astigmatism,” he said. The patient’s slit-lamp images and AC-OCT scans showed no major abnormalities and fluorescein staining was normal. It was only using in vivo confocal microscopy (IVCM) several years after his initial referral that the full damage to the sub-basal nerve plexus – with sprouting nerve fibres, decreased nerve density and the formation of microneuromas – became fully apparent. “In the end the patient was treated with preservative-free autologous serum eyedrops, which finally gave him complete relief of the symptoms. However, seven years after surgery, he still needs eye drops because the symptoms reoccur every time he stops the treatment,” he said. Dr Borderie noted that the extent of corneal denervation is a function of the type of refractive procedure used. “It is deeper with LASIK compared to SMILE, and deeper with SMILE compared to PRK,” he said. Hyperopia treatments tend to generate more nerve damage than those for myopia, with ablation zone size and flap thickness also playing a role in nerve damage, he added. The most common treatments for corneal neuropathy include preservative-free tear substitutes, sodium hyaluronate, topical cyclosporine, autologous serum, and systemic treatment of neuropathic pain, said Dr Borderie. Amniotic membrane transplantation may also be used for the most severe cases with associated neurotrophic ulcers where other treatments have failed, he said.

Tags: neuropathy, refractive surgery