• Grey Respond Lenses lenses have photochromic material throughout the entire thickness of the lens, they are less expensive than transitions but give a darker tint in thicker areas of the activated lens, thus giving a slightly patchy appearance.
• At present we don't supply Grey Respond Lenses, but our initial lab tests of this product have been very promising, the tensile strength has been found to be reasonable and because of the slightly higher index "1.56" they are a little thinner than true Transitions.
• The biggest drawback seems to be that once activated they don't clear as completely as Transitions lenses, but they are thinner and less expensive.

VTI Respond 1.56 Mid Index Fast Reacting Photochromic Lenses

• Brown Respond Lenses lenses have photochromic material throughout the entire thickness of the lens, they are less expensive than transitions but give a darker tint in thicker areas of the activated lens, thus giving a slightly patchy appearance.
• At present we don't supply Grey Respond Lenses, but our initial lab tests of this product have been very promising, the tensile strength has been found to be reasonable and because of the slightly higher index "1.56" they are a little thinner than true Transitions.
• The biggest drawback seems to be that once activated they don't clear as completely as Transitions lenses, but they are thinner and less expensive.

VTI Respond 1.56 Mid Index Fast Reacting Photochromic Lenses

• Great Value
• Lightweight
• Fast Reacting
• Scratch Resistant
• Competitively Priced