Published papers

Tear secretion is important as it supplies water to the ocular surface and keeps eyes moist. Both the parasympathetic and sympathetic pathways contribute to tear secretion. Although intracellular Ca2+ elevation in the acinar cells of lacrimal glands is a crucial event for tear secretion in both the pathways, the Ca2+ channel, which is responsible for the Ca 2+ elevation in the sympathetic pathway, has not been sufficiently analyzed. In this study, we examined tear secretion in mice lacking the inositol 1,4,5-trisphosphate receptor (IP3R) types 2 and 3 (Itpr2 -/-;Itpr3-/-double-knockout mice). We found that tear secretion in both the parasympathetic and sympathetic pathways was abolished in Itpr2-/-;Itpr3-/- mice. Intracellular Ca2+ elevation in lacrimal acinar cells after acetylcholine and epinephrine stimulation was abolished in Itpr2-/-;Itpr3-/- mice. Consequently, Itpr2-/-;Itpr3-/- mice exhibited keratoconjunctival alteration and corneal epithelial barrier disruption. Inflammatory cell infiltration into the lacrimal glands and elevation of serum autoantibodies, a representative marker for Sjögren's syndrome (SS) in humans, were also detected in older Itpr2-/-;Itpr3-/- mice. These results suggested that IP3Rs are essential for tear secretion in both parasympathetic and sympathetic pathways and that Itpr2 -/-;Itpr3-/- mice could be a new dry eye mouse model with symptoms that mimic those of SS. © 2014 Inaba et al.

Purpose. We determined whether functional visual acuity (VA) parameters and a dry eyes (DEs) symptoms questionnaire could predict DEs in a population of visual terminal display (VDT) users. Methods. This prospective study included 491 VDT users from the Osaka Study. Subjects with definite DE, diagnosed with the presence of DE symptoms, tear abnormality (Schirmer test ≤ 5 mm or tear breakup time [TBUT] ≤ 5 seconds), and conjunctivocorneal epithelial damage (total staining score of ≥3 points), or probable DE, diagnosed with the presence of two of them, were assigned to a DE group, and the remainder to a non-DE group. Functional VA was assessed, and DE questionnaires were administered. We assessed whether univariate and discriminant analyses could determine to which group a subject belonged. Sensitivity and specificity were assessed. Results. Of 491 subjects, 320 and 171 were assigned to the DE and non-DE groups, respectively. No significant differences were observed between DE and non-DE groups in Schirmer test value and epithelial damage, but TBUT value (3.1 ± 1.5 vs. 5.9 ± 3.0 seconds). The sensitivity and specificity of single test using functional VA parameters were 59% and 49% in functional VA, 60% and 50% in visual maintenance ratio, and 83% and 30% in frequency of blinking, respectively. According to a discriminant analysis using a combination of functional VA parameters and a DE questionnaire, six variables were selected for the discriminant equation, of which area under the curve (AUC) was 0.735. Sensitivity and specificity of diagnoses predicted by the discriminant equation were 85.9% and 45.6%, respectively. Conclusions. The discriminant equation obtained using functional VA measurement combined with a symptoms questionnaire may suggest the possibility for the first step screening of DE with unstable tear film. Since the questionnaire has an overall poor sensitivity and specificity, further amelioration may be necessary for the actual utilization of this screening tool. © 2014 The Association for Research in Vision and Ophthalmology, Inc.

Purpose: To investigate the short-term adverse effects of using rebamipide for the treatment of dry eye by assessing visual function and optical quality. Methods: This interventional noncomparative study included 14 right eyes of 14 healthy volunteers. Serial measurements of visual acuity (VA) and higher-order aberrations were obtained prior to instillation of the rebamipide suspension (baseline) and immediately after and at 5, 10, 20, and 30 min after instillation. Functional VA measurement was performed over a 60-s period with the subject blinking naturally. Ocular aberrations were measured for 10 s while the subject was told not to blink, but no topical anesthesia was applied. Each patient also filled out a questionnaire exploring the rebamipide-Associated adverse effects. Results: There was no significant difference between functional VA measured at baseline and at each time point after the instillation of rebamipide. In contrast, the root mean square of third-order and total higher-order aberrations increased significantly immediately after drug instillation (P<0.05). The severity of higher-order aberrations at baseline was similar to that observed at 5, 10, 20, and 30 min after instillation (P>0.05). Conclusions: The transient reduction in optical quality immediately after administration of rebamipide is corrected by the patient's natural blink reflex. The adverse effects observed in this study do not outweigh the benefits of rebamipide treatment. © Copyright 2014, Mary Ann Liebert, Inc.