This study, supported through a cooperative agreement with the National Eye Institute of the National Institutes of Health, was conducted by the Pediatric Eye Disease Investigator Group (PEDIG) at 9 clinical sites. Written informed consent was obtained from the parents of each participant. The complete protocol is available at http://public.pedig.jaeb.org
. The major aspects are summarized below.
The study enrolled children 6 to <48 months of age who had persistent NLDO after a failed probing. Other major eligibility criteria included onset of NLDO symptoms prior to 6 months chronological age; presence of at least one sign of NLDO (epiphora, increased tear lake, and/or mucopurulent discharge in the absence of an upper respiratory infection or ocular surface irritation); previous failed single primary probing procedure for NLDO; no history of nasolacrimal intubation, balloon catheter dilation, more than one probing, or dacryocystorhinostomy; and absence of Down syndrome.
The repeat probing surgery consisted of the dilation of at least one lacrimal punctum and the passage of a nasolacrimal probe into the nasopharynx at least once. Probe size was at investigator discretion. Procedures were performed under general anesthesia in a facility (ie, a hospital outpatient surgical department or ambulatory surgical center), or in the office without anesthesia at the preference of the investigator. Patency was confirmed in all cases by touching the probe in the nasopharynx with a second probe, by visualization of the probe beneath the inferior turbinate, or by recovery of fluorescein-colored saline from the nasopharynx after irrigation through the nasolacrimal system.
Subjects had follow-up visits timed 1 month (±1 week) and 6 months (±1 month) after surgery. At both visits, a trained and certified examiner other than the operating surgeon evaluated the presence or absence of each of three clinical signs of NLDO (epiphora, increased tear lake, and mucous discharge). In addition, a dye disappearance test (DDT) without topical anesthesia was performed by a certified examiner according to a protocol previously described.1
The primary outcome was treatment success or failure six months after surgery based on an assessment of clinical signs. Success was defined as the absence of all three clinical signs: epiphora, increased tear lake, and mucous discharge. Eyes that underwent another procedure prior to a given visit were considered treatment failures for that visit. The proportion of eyes with 6-month treatment success and a 95% confidence interval were computed by logistic regression using generalized estimating equations to adjust both the point estimate and the confidence interval for the correlation between eyes of subjects who had procedures on both eyes.6
Analyses were conducted using SAS version 9.1 (SAS Institute Inc. Cary, NC).