Sunglasses and it's varieties pptx Presenter Afsana Ansari B.Optometry 22nd batch

SUNGLASSES AND ITS VARIETIES
PRESENTER
AFSANA ANSARI
B.OPTOMETRY 22nd
BATCH
MMC, IOM
MODERATORS
DR.SANJEEV BHATTARAI
NIRAJ DEV JOSHI

 Optical Spectrum
 Effects Of UV Radiation
 Introduction to Sunglasses
Categories
Standards
Varieties
 Ideal Properties
 UV protective eyewear
 Summary
 References
PRESENTATION LAYOUT

 The electromagnetic spectrum is the range of frequencies of electromagnetic
radiation and their respective wavelengths and photon energies.
OPTICAL SPECTRUM

EFFECT OF UV RADIATION
 Conjunctiva : Pinguecula, Pterygium Lens: Cataracts
Cornea: Photophthalmia
Band shaped keratopathy Retina: Macular Degeneration

 Sunglasses are a form of protective eyewear designed primarily to prevent
bright sunlight and high energy visible light from damaging or discomforting
the eyes.
 Are the healthcare products that add an extra zing to the appearance of
wearer.
 Lens that transmits less than 67% of incident light.
American Bureau of Standards
 Prescription sunglasses improve visual performance and can used as an
ocular defense gadget.
INTRODUCTION

IDEAL PROPERTIES
 Reduce the intensity of sunlight for optimum visual comfort and visual
performance.
 Eliminate parts of the optical spectrum that are not required for vision and
are hazardous to the eyes.
 Provide enough protection while being worn during the day so that wearer’s
dark adaptation and night vision are preserved at night.
PITTS AND KLEINSTEIN

 Maintain normal color vision and allow the wearer to distinguish
traffic signals quickly and correctly.
 Resist impact and scratching and only require a minimum of care .
PITTS AND KLEINSTEIN

 Measure of the level of UV radiation.
 Values of the index range from zero upward - the higher the UVI, the greater
the potential for damage to the skin and eye, and the less time it takes for
harm to occur.
 An important vehicle to alert people about the need to use sun protection.
ULTRAVIOLET INDEX

A cosmetic lens— More for fashion than function.
 A general purpose lens—Used for sunglasses normally used by most
individuals.
A very dark special purpose lens— Appropriate for situations of very
intense light, such as for mountain climbing.
 A strongly colored special purpose lens—This type of lens might
filter certain spectral colors more heavily and others.
CATEGORIES
ANSI Z80.3-2001 sunglass and Fashion eyewear standard

ANSI Z80.3-2001 sunglass and Fashion eyewear standard

 The international standard for sunglasses is ISO 12312.
 The Australian Standard AS-NZS 1067:2003 defines standards for
sunglasses with respect both to UVA (wavelengths between 315 nm and
400 nm) and UVB transmittance.
 The five ratings for transmittance (filter) under this standard are based on
the amount of absorbed light, 0 to 4.
 "0" providing some protection from UV radiation and sunglare, and "4"
indicating a high level of protection, but not to be worn when driving.
STANDARDS FOR SUNGLASSES

Categories for the European standard:
 Category 0 – 80%-100% transmission – for fashion, indoor use, or cloudy days.
 Category 1 – 43%-80% transmission – low sun exposure.
 Category 2 – 18%-43% transmission – medium sun exposure.
 Category 3 – 8%-18% transmission – strong brightness, light reflected of water or
snow.
 Category 4 – 3%-8% transmission – intense sunshine for high mountains, glaciers; not
for use when driving or on the road.
European standard 2005

1.Lenses with the UV filter directly in the lens material:
The first lenses that were developed specifically to block UV light had a
yellowish cast.
2. Lenses with the UV filter in the coating:
These include all polycarbonates and many high-index plastic lenses.
3. Lenses with a dyed in UV filter:
Plastic lenses can be made UV inhibiting by immersion in a hot UV dye in the
same manner as is used to tint a lens.
EYEWEAR THAT BLOCK UV RADIATION

4. Polarizing lenses:
Good quality polarizing lenses block UV radiation.
5. Photochromic lenses:
In their darkened state, photochromic lenses are considered sufficiently
protective against UV light.
6. Lenses that go beyond UV protection:
Block out short wavelength (primarily blue) visible light. These are
generally referred to as “glare control lenses” .

 Photochromic lenses is major form of absorptive lenses.
 The word photochromatic derives from Greek words ‘Photo’ and ‘chroma’ means
Photo= Light
Chroma= Color
 Lenses whose absorption characteristics vary with the level and type of
illumination
 Are the lenses that darken on exposure to UV radiation and reverting to the
original state in the absence of sunlight .
PHOTOCHROMATIC LENSES

 Photochromic lenses are good option for those patients who are light
sensitive, require flexibility in their tints preference or those who have
pathological or genetic condition. Example; Albinism
 Can be important treatment for the patients with symptom of
photophobia and anterior segment inflammatory disease like uveitis.
INDICATIONS

 For, glass lens darkening process occurs as result of silver halide crystals
within the glass that are activated by UV and short visible radiation of
wavelength between 300-400nm.
 Process is same as photolytic dissociation of silver halide into silver and
halogen but here the process is reversible
GLASS PHOTOCHROMATIC

Sunlight passes through lens
UV Rays separately affect
silver chloride by separating ions
UV light + Chlorine=Cl+e
Free electrons combine with Ag to form chargeless silver and chlorine atoms to build up
during reaction to UV rays absorbing visible light and develop blue greyish layer along
surface of lens and glass appears dark
DARKENING PROCESS

When light is
ceased ,no
longer part of
chemical
reaction take
place
So copper(I)
chloride
interacts with
chlorine to
form copper
cu2+ Cu2+ combines
with Ag to form
cu+ and Ag+
Cl and Ag+ rejoin
once again to form
original silver
chloride and Cu
returns to original
copper(I) chloride
form as well
Photochromatic
glass appears clear

TYPES OF PHOTOCHROMATIC GLASS
 Photo Gray II
 Photosun II
Ff
ff
Faded
Darkened
PHOTOSUN II

 Photo gray Extra and Photo Brown Extra
PHOTO GRAY EXTRA

The photochromatic effect is achieved by organic compound(indolino
spirorazines i.e.ISN).
When activated by UV rays , the ISN molecules scatters absorbing
sunlight and reducing amount of visible light.
When removed, chemical reaction reverse and lens return to its clear
state.
PLASTIC PHOTOCHROMIC

1.TRANSITIONS
 Available in nearly every lens design,prescription and refractive index
including high index ,polycarbonate and trivex material.
 Incorporated scratch resistance and 100% UV protection.
 Available in gray brown, XTR active gray ,XTR active green.
TYPES

2.TRANSITION SPLITZ
Changes from one color to another when activated to light
Red lenses turn purple, yellow lenses turn orange and
blue lenses turn green.
3.KB CO TRANSHADES
Are unique polarized photochromic.
Available in glass or plastics and in gray and brown versions.

4.HOYA SUNGRAY
Are mid-index plastic photochromatic with UV-activating color changing
molecules dispersed throughout the lens material.
5.RODENSTOCK COLORMATIC EXTRA
Are the mid-index photochromatic created by mixing photochromatic dye
throughout these gray lenses.

Crizal UV Transition Classic Thin & Light
Eyezen+ Crizal Transitions Signature
ESPACE Plus transition
Varilux Progress transition
SOLIO Photochromic lens
Hoya Sensity Photochromic Lenses
PHOTOCHROMIC BRANDS IN NEPAL

1.Light intensity (both glass and plastic)
2. Temperature (both glass and plastic)
3. Previous exposures (exposure memory) (glass)
4. Lens thickness (glass)
FACTORS INFLUENCING PHOTOCHROMATIC PERFORMANCE

 Photochromic lenses are good absorbers of UV radiation.
 In their darkened state, glass photochromic lenses generally absorb 100% of
UVB radiation and 98% of UVA radiation.
 Plastic photochromic absorb 100% UVB and 99% UVA
PHOTOCHROMIC UV ABSORBING PROPERTIES

 Helps eye to cope up as they react to different light conditions during
day time.
 In their darkened state, glass photochromic lenses generally absorb
100% of UVB radiation and 98% of UVA radiation.
 Are immune to fatigue or deterioration of their photochromatic
performance with extended use
 Available in single vision, bifocal and multifocal.
 Gives visual comfort indoor and outdoor
ADVANTAGES

 Do not adjust with time immediately.
 Loses its darkening ability with time.
 Do not darken inside vehicles because windscreens/green glass absorbs
virtually 100% of UV light.
DISADVANTAGES

• Background: The purpose of the current study was to evaluate the effects of filtering by an activated photochromic
lens on visual performance in healthy adults. Glare disability, glare discomfort, heterochromatic contrast thresholds
and photo stress recovery time were assessed.
• Methods: A subject-masked, randomised, cross-over design was employed. Seventy-five healthy adults were
recruited, aged 19 to 73 years (mean = 45.61 ± 13.24 years). Visual functions were measured using three different
photochromic lenses that were partially activated with a steady state transmittance of 63 per cent T (Gray1), 71 per
cent T (Gray2), and 71 per cent T (Brown). These lenses were compared with a clear (92 per cent transmission)
polycarbonate lens. Glare disability was assessed as the intensity of a white (xenon)-light annulus necessary to
obscure a central grating target. Heterochromatic contrast thresholds were measured as absolute thresholds for a
monochromatic 570 nm target superimposed on a 460 nm circular background. Glare discomfort was quantified
using bio-imaging of the squint response as well as a Likert-based self-report scale. Photo stress recovery time was
recorded as the time necessary to regain sight of a grating target after intense light exposure. Glare discomfort and
photo stress recovery were only assessed for the Gray1 lens compared to placebo. Lens order was randomised
between subjects and conditions.

• Results: All visual functions measured were significantly improved (p < 0.05) for all of the activated photochromic
lenses tested versus the clear lens. In the glare disability and heterochromatic contrast conditions, numeric
differences (p < 0.09) were also seen between each of the three different activated photochromic lens types.
Glare discomfort and photo stress recovery times were improved in the Gray1 condition, as quantified by both
the squint and subjective responses (p < 0.05).
• Conclusion: Adding filtering via a photochromic lens significantly increased subjects' abilities to cope with intense
broadband and shortwave lighting conditions and to adapt back to normal viewing after being presented with an
intense photo stressor.

• Absorptive lenses used to protect the eyes from glare and harmful
radiations.
• Ocular conditions for prescribing tints are:
 Age related macular degeneration
 Retinitis pigmentosa
 Cataract
 Diabetic retinopathy
 Cone dystrophy
 Oculo-Cutaneous albinism
TINTED LENSES

 Improved vision clarity
 Increased color contrast
 Decreased light sensitivity
 Improved color perception
 Enhanced style and cosmetic appeal
BENEFITS

 Brown: It is a general purpose filter. It absorbs UV light well, enhances
contrast and a very good option for day driving and sun protection.
 Yellow: It absorbs blue, Violet and UV light rays. It lies at the peak spectral
acuity and makes everything brighter with contrast enhancing effect .But
it disturbs color perception to some extent. Yellow is a good option for
shooting, snow skiing and hunting.
OPHTHALMIC TINTED LENSES

 Green: It is a good option for both UV and IR radiation protection.It
acts as a contrast enhancer and provides true color perception.
 Grey: Grey is preferable is light sensitive people and also for jobs which
require accurate color perception with cool sunglass color.

PINK
Pink tints have a uniform transmission across the visible spectrum and
therefore do not cause any color distortion for the wearer.

 Red: It blocks the transmission of blue and green wavelengths with
sharp contrast. Red allow excellent depth perception in low light and
still suitable for skiing and hunting.
 Orange: It is an essence of brown tint. It increases the contrast and
reduces the transmission of blue and green wavelengths. It is an ideal
support for cycling, mountain tours, skiing etc.

 Eliminates the specularly reflected and horizontally polarized light.
 Improves the visual acuity and restores the natural balance of light intensities.
 lenses are dispenses to protect the eyes from the ill effect of horizontal waves
that cause glare and reduce the visual performance.
 Polaroid lenses can be useful in filtering glares during day driving with
enhanced contrast and good depth perception.
POLAROID LENSES

Originally manufactured with 2 sheets of glass laminated with adhesive to
either side of polarized film.
POLAROID LENSES

WHEN SHOULD POLARIZING LENSES USED?
To decrease driving fatigue and increase driving
safety.
For fishing and for boating on the water
For more visual comfort at the beach
To block UV radiation

 Polarizing lenses are good sunglasses
• Can be made as single vision lenses, bifocals, trifocals, and progressive
addition lenses as well.
• Available in glass, photochromic glass, plastic, photochromic plastic,
polycarbonate, and high-index plastic.
• Colors and tints are available, including mirrored and AR coating.

 Applied by vacuum process to front surface of the
lens causing the lens to have same properties as
two way mirror.
 Mirror coatings are often used in combination with a tinted lens to provide more
protection from intense sunlight.
 Mirror coated lenses work by reflecting back specific wavelengths whereas tints
work by absorbing the wavelengths or light energy.
 Reduces light transmission by reflection.
 Reflects UV and infrared rays and prevents glare.
MIRROR COATED LENSES

Reduce the Glare
Increase Your Brightness
Hide Your Eyes When Needed
Improve Resistance to Wear and Tear
BENEFITS

 Back surface reflection is the common problem of sun lenses.
 AR coating reduces mirrorlike reflections from the back surface and
enhance vision and comfort.
 Sun lenses with frontside AR coated enhances the wearers appearance
by reducing distracting glare off the front surface.
ARC COATING OF SUNGLASSES

 Overexposure to nonionizing radiations contributes to an aging effect in our eyes.
 Green tints have very good UV and IR absorption properties.
 Mirror coated lenses work by reflecting back specific wavelengths whereas solid
tints work by absorbing the wavelengths or light energy.
 Polaroid lenses are dispensed to protect the eyes from the ill effect of horizontal
waves that cause glare and reduces the visual performances.
 Antireflection coating on back surface of polarized lens means we do not even
have to fight little reflections that annoy our eyes.
SUMMARY

REFERENCES
 https://pubmed.ncbi.nlm.nih.gov/27346784/
 https://en.wikipedia.org/wiki/Sunglasses

Sunglasses and it's varieties pptx Presenter Afsana Ansari B.Optometry 22nd batch

Sunglasses and it's varieties pptx Presenter Afsana Ansari B.Optometry 22nd batch

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