tints Flashcards
graduated tint description
darker at top and light at bottom
can be single or dual coloured
pros of graduated tint
px can read in sunlight
cosmetics
cons of graduated tint
tint degrades with age
photochromic description
darkens when exposed to uv light
pros of photochromic
no separate sunglasses required
full uv protection
equitint can be used on high rx
cons of photochromic
take longer to lighten than darken
less reactive behind uv filter
residual colour with age
darken in cold temperatures
fixed tint description
glass- solid or laminated
plastic= dip dye
pros of fixed tint
solid doesn’t degrade with age as embedded within glass rather than dip dye
cons of fixed tint
one shade throughout. limited to uses and tint degrades with age
polarised tint description
polarised lens the vibrations are limited to one meridian. polarised in plane parallel to to reflecting surface.
pros of polarised tint
reduces glare and discomfort
good for px who fish, water sports
cons of polarised tint
can be used for driving however hard to see lcd displays on dashboard
ir lenses description
ir lenses protects against heat cataract and retinal burns from exposure to sun, furnaces and explosions
why must you apply uv coating to tinted lenses
pupils dilate–> more uv exposure–> more damage
why do px tint their lenses
enhance contrast
cosmesis
frame choice
protection