A Study of Result and Reproducibility of the Fluorescein Clearance test(FCT) Between Normal and Blepharospasm Patient

ABSTRACT

On the proposed fluorescein clearance test by Pflugfelder and Tseng, measurements of volume and concentration of instilled fluorescein, being changed by tear secretion, pumping action, during confined time, are able to discern tear turnover rate(tear clearance). We performed TBUT, Schirmer test and modified FCT to the 60 eyes of healthy person, to the 36 eyes of essential blepharospasm patient, and to the 32 eyes of hemifacial spasm patients. We modified the FCT to economize time. Under the topical anesthesia with 0.5% propacaine, test was performed after instilling a 20 microliter of Flucaine(0.25% fluorescein sodium, and 0.5% propacaine) into the conjunctival sac and standard Schirmer strip was then placed for another 10 minutes. The length of the portion was measured and the concentration of tint fluorescein was graded into 5 degrees(photodocumented classification under the cobalt blue light)(FCT 1). Waiting 10 minutes, a standard Schirmer strip was placed into with nasal stimulation and length and concentration was also measured(FCT 2). The agreement of classification was determined with Kappa values for evaluation for reproducibility and and reliability of FCT. The intra-observer agreement(examination repeated twice) was k=0.84 and the inter-observer agreement(two obsevers' examination) was k=0.77, which revealed a consistent result. Patients with blepharospasm was indicated decreased basal secretion compared with normal control(p<0.001) and also showed delayed tear clearance whith represented significant increased concentration(p<0.001). We concluded that FCT was revealed high reproducibility by intra-observer and inter-observer agreement and test may be useful diagnostic method to evaluate delayed tear clearance.