This research found chronic pain derived from dry eye disease can be permanent. This is an exert from a pre-publication titled “Neuropathic Ocular Pain: An Important Yet Underevaluated Feature of Dry Eye by Galor A, Levitt RC, Felix ER, Martin ER, Sarantopoulos CD. Eye (Lond). 2014 Nov 7.
People who suffer from dry eye have a variety of complaints including blurred vision, irritation, and pain. The pain that these patients typically experience is often a sharp, transient, stabbing pain, or a more chronic situation known as neuropathic pain. Neuropathic pain is thought to be secondary to changes in the somato-sensory pathway. It is this change that can be permanent even after dry eye syndrome is relieved.
The authors of this review conducted a PubMed search using key words of “dry eye” and various descriptors of pain. They determined that environmental factors and inflammation can cause ocular surface damage which can trigger alterations in peripheral corneal nerves. These changes are thought to cause dry eye sensations and phenotypic modifications which lower the activation threshold of the nerve fibers. If ocular surface damage persists, or if the inflammatory cascade is not dampened, shifts may occur in the central nervous system (CNS), producing “central sensitization.” The hallmark of central sensitization is that pain continues to occur, even after the damage has resolved. This is commonly seen in dry eye patients where they continue to be symptomatic but no ocular surface findings are observed. The process of central sensitization may initially be reversible, but it often becomes permanent.
After traditional dry eye therapy to improve the health of the eye, many examinations have determined the dry eye symptoms are much improved. Patients still complain of eye pain. Conclusion is, – if central sensitization has already occurred, pain may linger regardless of the successful management of the ocular surface. Unfortunately, therapy for managing this type of chronic ocular pain is lacking and would be an interesting area of development.