Polynomial-Curved Bespoke Prescription Lens for Respiratory Protection

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Biotechnology OBJECTIVE: Develop a respirator lens that can provide visual correction on a polynomial curved surface (e.g. M50 respirator lens) with varied prescription strength as needed at either eye. DESCRIPTION: Most single-lens full facepiece air-purifying respirators (APR) are unable to provide vision correction via the primary lens of the respirator due to its complex geometry and the requirement of providing different prescription strengths for each of the wearer's eyes. Instead, vision correction is traditionally provided through a vision correction assembly that is hung inside the respirator, close to the user's eyes. The vision correction assembly available for the M50 can accommodate lenses ranging from -10.00 to +8.00 Diopters in power. While the inserts offer vision correction functionality to the respirator, the accommodation of inserts increases eye relief and thus negatively impacts compatibility with external sighting systems. This effort seeks to develop a prescription lens solution that can eliminate the need for an internal vision correction assembly building the visual correction directly into the primary lens of the respirator. These lenses would need to be made-to-order with specified diopter strengths available on either half of the respirator lens in order to accommodate conditions such as anisometropia which requires different prescriptions in each eye. The lens would also need to support a range of prescription strengths ranging from -10.00 to +8.00 Diopters and maintain the current shape and size of the primary lens of an M50. Since the primary lens of a full facepiece respirator is a part of the critical sealing surface, this lens will also need to have threat agent permeation resistance characteristics required by the NIOSH Statement of Standard for Chemical, Biological, Radiological, and Nuclear (CBRN) Full Facepiece APR. Durability and optical requirements shall compare favorably to existing military respirator materials and shall comply with the requirements set forth in MIL-STD 810G. PHASE I: Investigate lens solutions that demonstrate two different prescription strengths on a single flat surface and provide eight (8) flat circular coupons (4 diameter, 0.05 thickness) that are resistant to chemical warfare agent materials as required by the NIOSH Statements of Standard for CBRN Full Facepiece APR to be subjected to government testing. Additionally provide two (2) coupons that demonstrate two different prescription strengths on a polynomial-curved surface, constructed using the same materials as the flat coupons. PHASE II: Refine the material to develop a full respirator lens of size and shape equivalent to the primary lens of the M50 APR. This lens shall be resistant to chemical warfare agent materials, capable of providing a different prescription strength on each half and demonstrate equivalent optical properties to the primary lens of the M50. PHASE III DUAL USE APPLICATIONS: PHASE III: Further improve and refine the lens material, demonstrating the ability to be integrated into a full facepiece APR. Additionally, demonstrate that the technology is durable and suitable for military combat applications. PHASE III Dual Use Applications: Potential alternative applications include industrial, pharmaceutical, healthcare, international, and other commercial respiratory protection uses. REFERENCES: 1. https://www.avon-protection.com/downloads/product%20datasheets/accessories/outserts/Avon-Protection_Vision-Correction-Assembly_Data-Sheet_EN.pdf ; 2. https://www.atec.army.mil/publications/Mil-Std-810G/MIL-STD-810G.pdf KEYWORDS: individual protection; respiratory protective mask; protective eyewear; lens; prescription