RESUMO
The purpose of this study was to investigate the effect of high molecular weight hyaluronan (HMWHA) eye drops on subbasal corneal nerves in patients suffering from severe dry eye disease (DED) and to evaluate the damage of subbasal corneal nerves associated with severe DED. Designed as an international, multicenter study, 16 patients with symptoms of at least an Ocular Surface Disease Index (OSDI) score of 33, and corneal fluorescein staining (CFS) of at least Oxford grade 3, were included and randomized into two study arms. The control group continued to use their individual optimum artificial tears over the study period of eight weeks; in the verum group, the artificial tears were substituted by eye drops containing 0.15% HMWHA. At the baseline visit, and after eight weeks, the subbasal nerve plexus of 16 patients were assessed by confocal laser scanning microscopy (CSLM). The images were submitted to a masked reading center for evaluation. Results showed a significant increase of total nerve fiber lengths (CNFL) in the HMWHA group (p = 0.030) when compared to the control group, where the total subbasal CNFL did not significantly change from baseline to week 8. We concluded that in severe DED patients, HMWHA from topically applied eye drops could cross the epithelial barrier and reach the subbasal nerve plexus, where it exercised a trophic effect.
RESUMO
Chronic ocular surface diseases such as dry eye, blepharitis, and neurotrophic keratopathies represent a significant and a growing therapeutic challenge. The basis of this expanding prevalence is multifactorial and may due to issues such as an aging population, an increasing use of video display terminals, and increases in frequency of refractive surgeries. The growing incidence of diseases such as diabetes may also be a contributing factor. Current treatments for ocular surface disease include artificial tears, lubricants, tear duct plugs, steroids, antibiotics, cyclosporine, scleral lenses, and serum tears. Treatment choices depend on the type and severity of the disease, but in general positive outcomes are limited because many of these treatments do not fully address the underlying disease process or promote mechanisms that facilitate long-term wound repair. From minor corneal injuries to more severe inflammatory-mediated pathologies, clinicians need agents that promote corneal healing and reduce the inflammatory response to prevent visual disturbances and improve quality of life. A focus on treatments that reduce the inflammatory responses while accelerating corneal epithelial growth would represent a major step forward from current treatment options. Increasing evidence suggests that thymosin beta 4 (Tß4), a naturally occurring polypeptide, can elicit this spectrum of therapeutic responses: a rapid corneal reepithelialization and a reduction in corneal inflammation. This chapter serves as a review of standard therapies as well as recent advancements in the development of newer therapies that includes the use of Tß4 that is proving to be an exciting new agent for the management of ocular surface disease.