Eye injuries are common in workplaces, with over 2,000 occurring daily and 10-20% resulting in temporary or permanent vision loss. Proper eye protection could prevent around 90% of injuries. There are three ways to prevent eye injuries - assessing hazards, eliminating hazards through measures like machine guarding, and using appropriate eye protection such as laminated, heat-toughened, or chemically-toughened safety lenses made of materials like glass, CR-39 plastic, or impact-resistant polycarbonate.

1. Beenish Latif
Optometrist
COAVS/ KEMU
16-04-2020

2.  Eye injuries in the workplace are very common.
 More than 2,000 people injure their eyes at work
each day.
 About 1 in 10 injuries require one or more
missed workdays to recover from.
 Of the total amount of work-related injuries, 10-
20 % will cause temporary or permanent vision
loss.
 Experts believe that the right eye protection
could have lessened the severity or even
prevented 90% of eye injuries in accidents.

3.  There are three things you can do to help
prevent an eye injury
1) Know the eye safety dangers at work-
complete an eye hazard assessment
2) Eliminate hazards before starting work. Use
machine guarding, work screens, or other
engineering controls)
3) Use proper eye protection.

4.  Laminated glass safety lenses
 Heat toughened safety lenses
 Special heat toughened safety lenses
 Chemically toughened safety lenses

6.  These lenses are not very strong.
 Able to withstand significantly more impact
than a standard glass lens.
 These are made by cementing together two
pieces of glass with cellulose acetate.
 By modern standards, these lenses could
hardly be safe.
 The broken glass piece s are usually sharp
and potentially destructive.

7.  Polarised laminated lenses are available
today, but are designed to provide safety.
 Made by sandwiching a piece of polarising
material between pieces of glass.
 Laminated glass safety lenses have not been
produced for many years.

8.  The production of heat toughened lenses
begins by surfacing a thick glass lens.
 A heat toughened safety lens needs to be
made thicker than a standard stock lens.
 Heat toughened lenses are often said to be
safe.
 Broken pieces are shaped like cubes and
blunt.

9.  These lenses are somewhat thinner than the
usual heat toughened lens.
 Can be identified with a polarizing strain
view.
 This strain pattern is different than
conventional heat toughened lens.

10.  In chemical toughened process, large batches
of cut lenses are first preheated .
 Then these are immersed in the bath of
chemical( molten potassium nitrate at temp
of 440C) .
 These lenses are fairly thin, extremely
regular and strong.
 The process is fully automated, because the
chemical used are hot and dangerous.

11.  Glass lenses
 Are not easily scratched
 Can be used around harsh chemicals
 Can be made in your corrective prescription
 Are sometimes heavy and uncomfortable

12.  CR-39 refers to the material that is used to make the
majority prescription lenses.
 It is an optical grade plastic polymer recognized for
its light weight, chemical resistance properties and
'tint-ability'.
 In comparable prescriptions it is approximately half
the weight of glass lenses, while being slightly
thicker.
 Its impact resistance is greater than glass but does
not rise to the level of polycarbonate
 it is not recommended for active sports and
motorcycling.
 It is more scratch resistant than polycarbonate, but
will scratch if not properly taken care of.

13.  Polycarbonate is an impact resistant material.
 It is becoming used more widely in recent times -
especially for motorcycling and action sports.
 It is also used frequently for the glazing of
rimless frames because of these properties.
 Although polycarbonate is impact resistant, it
should not be considered indestructible.
 Polycarbonate is the strongest material available
and will have the tendency to break into larger
pieces, instead of the CR39's smaller pieces.

14.  Polycarbonate is thinner than standard CR39.
 Polycarbonate lenses are ten times more
impact resistant than other plastics making
them highly suitable for action sports.
 They offer UV protection and stop 99.9% of
rays from the sun, fluorescent lights and
computer screens.
 Our polycarbonate lenses are supplied with a
scratch resistant coating and are thinner than
standard lens and therefore more
comfortable to wear.

15.  Polycarbonate
 Strongest material
for impact
resistance
 Lightweight
 Can be coated for
scratch resistance
 Most have built-in
UV radiation
protection
 Plastic (CR39)
 About one-half the
weight of glass
 Resistant to
solvents and pitting
 More choices for
coatings and tinting