1. JAMA Ophthalmology Journal Club Slides: Timing of Intervention in Congenital Nasolacrimal Duct Obstruction
Sathiamoorthi S, Frank RD, Mohney BG. Spontaneous resolution and timing of intervention in congenital nasolacrimal duct obstruction. JAMA Ophthalmol. Published online August 30, doi: /jamaophthalmol

2. Introduction Importance:
Although the overall rate of spontaneous resolution in congenital nasolacrimal duct obstruction (CNLDO) and efficacy of probing have been documented in the literature, the optimal timing of intervention has not been established.
Objective:
To describe the trends of spontaneous resolution in a large cohort of children with CNLDO.
To report new findings regarding spontaneous resolution of CNLDO.
To investigate when surgical intervention may be appropriate for children with CNLDO.

3. Methods Study Design, Setting, and Participants:
The medical records of 1998 consecutive patients younger than 5 years diagnosed as having CNLDO while residing in Olmsted County, Minnesota, from January 1, 1995, through December 31, 2004, were retrospectively reviewed.
Each individual chart was reviewed for confirmation of diagnosis of CNLDO and date of resolution of symptoms. Multiple patient encounters over several years were reviewed as well to confirm full resolution of symptoms.
Main Outcomes and Measures:
Rate of spontaneous resolution over time and by sex.

4. Methods Statistical Analysis:
A mixture of statistical models including marginal Cox regression models and Kaplan Meier curves were used to analyze the data obtained from this large cohort.
Limitations:
Retrospective study design.
Incomplete documentation by clinicians.
Incomplete or untimely well-child and physician visits.
Residents may have sought care outside of Olmsted County, Minnesota.
Demographics of Olmsted County, a relatively homogenous semiurban white population.

5. Results
Among 17 713 newborns born during a 10-year period,1998 children were diagnosed as having CNLDO.
The cohort was diagnosed at a median age of 1.2 months (interquartile range, ), was 48% girls (n = 959), and was 89% white (n = 1626; 173 were unreported).
Forty affected infants (2.0%) were lost to follow-up. Of the 1958 infants followed up, CNLDO in 925 (47.3%) spontaneously resolved by age 3 months, in 1300 (66.4%) by 6 months, in 1472 (75.7%) by 9 months, and in 1516 (78.4%) by 12 months.
Congenital nasolacrimal duct obstruction resolved in boys 0.5 months (95% CI, ; P < .001) faster than girls (median, 2.9 vs 3.4 months).
Unilateral obstructions resolved 0.2 months (95% CI, ; P = .002) faster than bilateral (median, 3.1 vs 3.3 months) one.
Children probed at 15 months or older had decreased odds of resolution after probing (OR, 0.11; 95% CI, ; P = .04) relative to children probed at age 12 to 14 months.

6. Results Overall Percentage Without Spontaneous Resolution Over
Time Using Kaplan-Meier Methods in 1958 Infants

7. Results Percentage of Children Whose Obstruction Eventually
Spontaneously Resolved at Any Time After Specified Age

8. Results Associations Between Probing Age and CNLDO
Resolution Using Multivariable Logistic Regression

9. Comment
The rate of resolution in CNLDO was highest in the first months of life, decreasing until 9 months of age, after which the rate changed minimally.
Patients probed at 15 months or older had lower odds of resolution of CNLDO without additional treatment compared with those probed up to age 15 months.
Given these findings, surgical intervention between 9 and 15 months appears to be a reasonable treatment strategy. This suggests both an earlier and narrower range of ages for intervention when compared with the current general practice of probing after 1 year of age.
While childhood anesthesia has been linked to cognitive impairment later in life, the exposure to anesthesia during a probing is brief and single. Further research is necessary to quantify risk.

10. Conflict of Interest Disclosures
Contact Information
If you have questions, please contact the corresponding author:
Brian G. Mohney, MD, Department of Ophthalmology, Mayo Clinic, 200 First St SW, Rochester, MN
Funding/Support
The study was supported by Research to Prevent Blindness Inc and the Rochester Epidemiology Project (grant R01-AG from the National Institute of Arthritis and Musculoskeletal and Skin Diseases).
Conflict of Interest Disclosures
All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.