Purpose:
To describe the systems utilized in design and commissioning of a controlled environment room(CER) with regulated air flow capable of reaching extreme temperature(65-95°F±1°F) and relative humidity(25-80%±3%) ranges in order to study the effects of environmental variables on the ocular surface in subjects with dry eye(DE).
Methods:
We created a CER(12’ wide, 12’ deep, 8’ high) adjacent to an anteroom with double paned glass enabling subject monitoring. Drywall, insulated with 2.5" fiberglass, was painted with epoxy to minimize migration of heat and moisture in and out of the room. Vinyl faced ceiling tiles and VCT flooring were used. A custom designed air flow and HVAC system, housed in a neighboring mechanical room, was installed to achieve specified temperature and relative humidity (RH) ranges.
Results:
Achievable temperature and RH conditions in the CER were validated using a NIST-calibrated and traceable HOBO recording device and found to be between 65-95°F ±1°F and 25-80% ±3%, respectively. Downloadable data from mentioned recorder confirmed upon repeat testing that desired conditions were reproducible. Trending this data proved environmental stability over time. Undesired surface condensation was encountered with rapid changes in temperature. This was solved by limiting rate of change to a max of 4°F/hour or 3% RH/hour. 3D rendering of the CER is shown in figure 1.
Conclusions:
DE is a complex syndrome that exhibits marked variability from person to person. Its severity is very likely affected by ambient environment. The potential value of the CER lies in its strict control of temperature, RH, and air flow. Removing confounding variables allows investigators to gather standardized, reproducible measurements of ocular surface characteristics that may lead to better definition of this disease. Furthermore, the CER facilitates study of adverse environments on the ocular surface, and efficacy of therapeutics. Final success of the CER required significant investment in infrastructure and a multidisciplinary approach to design.
Keywords: cornea: tears/tear film/dry eye • cornea: clinical science • cornea: epithelium