Photo Credit: Obencem

The following is a summary of “Dynamic viscosity of the wall of the lacrimal sac in disorders of the patency of the lacrimal ducts,” published in the April 2024 issue of Ophthalmology by Yartsev, et al.

Researchers conducted a retrospective study to investigate how the resistance to deformation of the lacrimal sac wall differs in patients with blockages in their tear ducts caused by various underlying conditions.

They involved 35 cases,  21 with primary nasolacrimal duct obstruction (PANDO) and 14 with secondary nasolacrimal duct obstruction after radioiodine therapy (SALDO). Biomechanical properties of the lacrimal sac were assessed using a test bench. The methodology involved applying pressure to the sample at a controlled rate and recording force data from a sensor. Calculations were made for the area under the curve (AUC) and peak viscosity. Additionally, a qualitative analysis of the curve was performed.

The results showed that the median AUC for patients with PANDO was 17 × 10⁶ [6 × 10⁶; 19 × 10⁶] N/m² × s, while for patients with SALDO it was 21 × 10<⁶ [13 × 10⁶; 25 × 10⁶] N/m² × s. Statistical analysis revealed a significant intergroup difference (P=0.048). Median peak viscosity for PANDO patients was 29 × 10⁶ [25 × 10⁶; 35 × 10⁶] N/m², compared to 32 × 10⁶ [21 × 10⁶; 41 × 10⁶] N/m² for SALDO patients, with a  notable qualitative differences in the curves obtained.

Investigators concluded that past tear duct blockage caused by radioiodine treatment (SALDO) resulted in stiffer lacrimal sacs compared to those with congenital blockages (PANDO).

Source: link.springer.com/article/10.1007/s10792-024-03112-x