Topical 0.1% Prednisolone Lowers Nerve Growth Factor Expression in Keratoconjunctivitis Sicca Patients

PurposeTo compare nerve growth factor (NGF) levels in tears and on the ocular surfaces of normal control and non–Sjögren’s type keratoconjunctivitis sicca subjects, and to investigate the effect of 0.1% prednisolone eyedrops on NGF levels in keratoconjunctivitis sicca patients.DesignProspective, double-masked, randomized, comparative clinical trial.ParticipantsForty-one keratoconjunctivitis sicca patients and 23 age- and gender-matched healthy subjects.MethodsBaseline tear NGF levels were measured in keratoconjunctivitis sicca patients and healthy control subjects using enzyme-linked immunosorbent assays. Keratoconjunctivitis sicca patients received 0.1% prednisolone drops in one eye and 0.1% hyaluronic acid drops in the other, 3 times a day for 28 days. Also, impression cytology (IC) and immunostaining for NGF on conjunctival epithelium were performed on both groups.Main Outcome MeasuresTear NGF/total tear protein (TP) concentration ratio, IC and NGF immunocytologic staining, subjective symptom scale, tear breakup time, and Schirmer values.ResultsKeratoconjunctivitis sicca patients were found to have baseline tear NGF concentrations higher than those of age- and gender-matched healthy control subjects (65.9±14.5 vs. 122.1±45.3 pg/μg, P<0.0001). In keratoconjunctivitis sicca patients, prednisolone treatment for 28 days resulted in a decrease in tear NGF levels, symptom scores, and IC scores, whereas hyaluronic acid treatment had no such effect (68.2±25.0 pg/μg vs. 108.0±43.4 pg/μg, P<0.0001 for tear NGF/TP ratio; 2.16±1.01 vs. 3.39±1.50, P = 0.0014 for symptom scale; 1.05±0.67 vs. 1.61±0.86, P = 0.0317 for IC). Measurements taken at both 14 and 28 days indicated that neither prednisolone nor hyaluronic acid treatment affected breakup time or Schirmer values.ConclusionKeratoconjunctivitis sicca patients showed elevated levels of tear NGF, which were decreased by treatment with 0.1% prednisolone. These data suggest that ocular surface NGF may play an important role in ocular surface inflammation processes associated with dry eyes.