Purpose
Windborne pollen is implicated in seasonal allergies, including ocular symptoms, and pollen adhesion to contact lens (CL) materials may increase direct exposure time and the likelihood that grains will break down and release their allergenic cytoplasmic contents. The purpose of this project was to develop a device for exposing CL materials to windborne pollen and allow quantification of pollen deposition.
Methods
A small, modular bench top wind tunnel was fashioned and validated. It consists of an enclosed circular tunnel within which CLs can be mounted and through which pollen is carried by adjustable air velocities generated by 2 equidistant fans within the tunnel. Validation of the chamber’s capability to deterministically deposit pollen on lenses was undertaken using 4 pollen species (white pine, common ragweed, Kentucky bluegrass, silver birch) and 7 commercial hydrogel and silicone hydrogel lens types. CLs were tested with and without prior incubation in an artificial tear solution (ATS). Exposures were run for 30 seconds at 5 mph and concentrations from 106-107 grains/m3, depending on pollen type, which simulates an accelerated 13 hour exposure of 640-1200 grains/m3, a range often encountered during allergy season. Exposed CLs were imaged under brightfield or fluorescence microscopy for pollen counting. Analyses were conducted on all lens types pooled together to obtain a global impression of pollen deposition.
Results
The chamber successfully deposited pollen on CLs and significant differences were found between pollen species in their deposition (p<0.0001). No statistical difference was noted due to ATS incubation (p=0.0924), although there was a trend of reduced deposition (Fig 1).
Conclusions
The device has proven successful at depositing pollen on CL materials. It may be used to measure the adherence of different species of pollen at varying concentrations and exposure times to any CL material.