Tear Flow Rate Significantly Reduced With Lacrimal Duct Obstruction

In primary acquired nasolacrimal duct obstruction, the lacrimal gland’s reflex secretory activity is reduced.

Tear flow rate in eyes with primary acquired nasolacrimal duct obstruction (PANDO) is significantly reduced compared with eyes without PANDO, according to a study published in the British Journal of Ophthalmology

Researchers evaluated 30 patients (median age, 45.5 years; 25 women) with unilateral PANDO who had epiphora for a mean duration of 20 months. They performed direct assessment of the lacrimal gland activity in these patients. Additional testing included noninvasive tear break up time, tear meniscus height, Schirmer I testing, and Ocular Surface Disease Index (OSDI) scoring. The main outcome measure was the difference in mean tear flow rate between the eye with PANDO and the contralateral uninvolved eye.

The researchers report that the mean OSDI score was 6.3. The noninvasive tear break up time (mean 11.56 vs 11.58 s; P =.49) and Schirmer I values (mean 18.83 vs 19.4mm; P =.313) were similar between eyes with PANDO and eyes without PANDO.  

The morphology in the palpebral lobe (size 29.3 vs 28.6mm2, P =.41) and the number of lacrimal ductular openings (median 2 vs 2.5) were comparable between the 2 eyes, the study shows. The mean tear flow rate from the lacrimal glands in eyes with PANDO showed a significant reduction compared with the contralateral uninvolved side (0.8±0.24 vs 0.99±0.26 µL/min; P =.014).

The fact that patients with PANDO did not have increased OSDI scores and did have normal tear film parameters, rules out reflex epiphora secondary to tear film instability, the report explains.

“The present study supports the existence of potential feedback communications between tear secretion and tear outflow. However, the ocular surface parameters other than TMH are not different between the PANDO and the healthy eyes,” according to the researchers. “This study provides the basis for future research in understanding the link between tear secretion and tear drainage pathway.”

Study limitations include lack of basal tear secretion assessment in the lacrimal gland, variability in the range of PANDO disease duration, and lack of data regarding the extent of regulatory feedback mechanisms. 

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or research companies. Please see the original reference for a full list of authors’ disclosures.  


Singh S, Srivastav S, Bothra N, Paulsen F, Ali MJ. Lacrimal gland activity in lacrimal drainage obstruction: exploring the potential cross-talk between the tear secretion and outflow. Br J Ophthalmol. Published online May 4, 2023. doi:10.1136/bjo-2022-322577