بسم الله الرحمن بسم الله الرحمن الرحیمالرحیم
By :Sotoudeh Manesh MDMD
Occupational eye disorders Occupational eye disorders
ImportantImportant
Ergophthalmology Ergophthalmology
USA:1.4 million injuryUSA:1.4 million injury &illness&illness in2002 in2002
- 47% of all head injury- 47% of all head injury
- ocular foreign body:38%- ocular foreign body:38%
- contusion/abrasion:27%- contusion/abrasion:27%
- burn:12%- burn:12%
- conjectivitis:11%- conjectivitis:11%
Non-construction>welder>cutter>truck driverNon-construction>welder>cutter>truck driver
- 4%workers compensation claim &1%total paymnt - 4%workers compensation claim &1%total paymnt
Two General Types of Vision andTwo General Types of Vision andEye Assessments Can Be DifferentiatedEye Assessments Can Be Differentiated
• ScreeningScreening
— — Identifies those at high riskIdentifies those at high risk
or in need of a professionalor in need of a professional
examinationexamination
— — May detect disorders inMay detect disorders in
early, treatable stageearly, treatable stage
— — Provides public withProvides public with
valuable information andvaluable information and
education about eye careeducation about eye care
— — Results in referral to an eyeResults in referral to an eye
care professional or primarycare professional or primary
care providercare provider
• ExaminationExamination
— — Examines subjects for Examines subjects for
eyeeye
disorders and diseasesdisorders and diseases
— — Diagnoses eye disordersDiagnoses eye disorders
and diseasesand diseases
— — Prescribes treatmentPrescribes treatment
Source: Prevent Blindness AmericaSource: Prevent Blindness America
Components Of Vision ScreeningComponents Of Vision Screening
History and symptomsHistory and symptoms
Visual acuity at any distanceVisual acuity at any distance
Visual fieldVisual field
Colour visionColour vision
Depth perceptionDepth perception
Contrast sensitivityContrast sensitivity
Visual acuityVisual acuity
Snellen chart Snellen chart
Acuity at Acuity at
Near&Distance Near&Distance
Near visual acuityNear visual acuity
• DefinitionDefinitionThe ability to see clearly at a normal reading The ability to see clearly at a normal reading
distancedistance
• Method of measuringMethod of measuringJaeger card-reduced snellen chartJaeger card-reduced snellen chart
• Causes of decreased near V.A in the Causes of decreased near V.A in the presence of normal distance V.Apresence of normal distance V.A
Presbyopia,uncorrected hyperopia,centerallyPresbyopia,uncorrected hyperopia,centerally located cataracts and drug side effectslocated cataracts and drug side effects
Visual fieldVisual field
Confrontation testConfrontation test
primetryprimetry
Visual fieldVisual field
• Normal extensionNormal extension 70 degrees Inferiorly, 60 degrees superiorly,95 degrees 70 degrees Inferiorly, 60 degrees superiorly,95 degrees
temporally and 60 degrees nasally.temporally and 60 degrees nasally.
Total horizontal visual field extent to 190 degreesTotal horizontal visual field extent to 190 degrees
• Factors that influenceFactors that influence the visual field the visual field Size, distance, background illumination, colour,Size, distance, background illumination, colour,
Kind of job, Bi or monocular vision, age, use ofKind of job, Bi or monocular vision, age, use of
Personal protective device ( safety spectacle)Personal protective device ( safety spectacle)
Color blindnessColor blindness
Normally, there are three kinds of Normally, there are three kinds of cones (each one sensitive to a cones (each one sensitive to a specific range of wavelengths):specific range of wavelengths):
""redred" cones (64%)" cones (64%)""greengreen" cones (32%)" cones (32%)""blueblue" cones (2%) " cones (2%)
The normal human retina contains two kinds of light sensitive cells: the rod cells (active only in low light) and the cone cells (active in normal daylight and responsible for color perception).
The different kinds of inherited color blindness result from partial or complete loss of function of one or more of the different cone systems.
Different Types of Color BlindnessDifferent Types of Color Blindness
• Monochromacy:Monochromacy: occurs when two or all three of the cone occurs when two or all three of the cone
pigments are missing and color and lightness vision is reduced to pigments are missing and color and lightness vision is reduced to
one dimension. one dimension.
Total color blindnessTotal color blindness
• Dichromacy:Dichromacy: occurs when only one of the cone pigments is occurs when only one of the cone pigments is
missing and color is reduced to two dimensions.missing and color is reduced to two dimensions.
Partial color blindnessPartial color blindness
red-greenred-green
blue-yellowblue-yellow
DichromacyDichromacy
Photoreceptor AnatomyPhotoreceptor Anatomy
• Example: if you Example: if you
stimulate all 3 types of stimulate all 3 types of
cones about equally the cones about equally the
result is white or no result is white or no
color. color.
Colour vision testColour vision test
Ishihara
plates
Colour vision deficiency in wokplaceColour vision deficiency in wokplace
• StyreneStyrene
• TolueneToluene
• PerchloroethylenePerchloroethylene
• Carbon disulfideCarbon disulfide
• Metallic mercurryMetallic mercurry
• Mercury vapporMercury vappor
• n-hexann-hexan
Depth perception Depth perception ((Stereopsis)Stereopsis) The ability to precieve depth or relative distanceThe ability to precieve depth or relative distance
Some jobs that need stereoscopic visionSome jobs that need stereoscopic vision Furk-lift truck operator , crane driver, pilot ,Furk-lift truck operator , crane driver, pilot ,……
Factors that influence depth perceptionFactors that influence depth perception Uncorrected refractive errores, amblyopia , squintUncorrected refractive errores, amblyopia , squint
low level of illumination , anisometropia , age ,low level of illumination , anisometropia , age ,
Advantages of binocular vision over monocularAdvantages of binocular vision over monocular The presence of stereopsis , improved visual acuity , an enlarged The presence of stereopsis , improved visual acuity , an enlarged
Field of peripheral vision , slightly brighter of objectField of peripheral vision , slightly brighter of object
Clinical tests for stereopsisClinical tests for stereopsis Contour stereotestContour stereotest Titmus stereotestTitmus stereotest
Random dot stereotestRandom dot stereotest Frisby testFrisby test
Random Dot-E testRandom Dot-E test
Clinical Contrast Sensitivity TestsClinical Contrast Sensitivity Tests
• Pelli-Robson chartPelli-Robson chart
• Regan low-contrastRegan low-contrast
• Vistech chartVistech chart
• Melbourne edge testMelbourne edge test
Occupational EYE Occupational EYE Illness Illness
EYE injuriesEYE injuries
EYE DiseasesEYE Diseases
EYE Chemical BurnsEYE Chemical Burns
1.1. Alkali burnsAlkali burns
2.2. Acid burnsAcid burns
3.3. IrritantsIrritants
Eye Acid BurnsEye Acid Burns
Sulfuric acidSulfuric acidNitric acidNitric acidChlorohydric acidChlorohydric acidHipochloric acidHipochloric acidPerchloric acidPerchloric acidFlurohydric acidFlurohydric acidCholorCholorSo2 So3 So2 So3 No2 N2o4 ?No2 N2o4 ?
Alkali BurnsAlkali Burns
Sodium hydroxideSodium hydroxide
Potassium hydroxidePotassium hydroxide
AmoniaAmonia
CementCement
LyeLye
DetergentsDetergents
Emergency Emergency
• Treatment should be immediate, even Treatment should be immediate, even
before making vision tests!before making vision tests!
• Premedicate with proparacaine or Premedicate with proparacaine or
tetracaine.tetracaine.
• Copious irrigation: LR or NS X 30 min.Copious irrigation: LR or NS X 30 min.
• Wait 5 minutes and check pH. If not Wait 5 minutes and check pH. If not
normal, repeat.normal, repeat.
Mild-to-Moderate Chemical BurnsMild-to-Moderate Chemical Burns
• Critical signsCritical signsCorneal epithelial Corneal epithelial
defects range from defects range from
scattered superficial scattered superficial
punctate keratitis punctate keratitis
(SPK) to focal (SPK) to focal
epithelial loss to epithelial loss to
sloughing of the entire sloughing of the entire
epitheliumepithelium
• Other Signs:Other Signs:Focal area of conjunctival Focal area of conjunctival
chemosis.chemosis.
Hyperemia.Hyperemia.
Mild eyelid edema.Mild eyelid edema.
Mild-anterior chamber Mild-anterior chamber
reaction.reaction.
11stst or 2 or 2ndnd degree burns to degree burns to
periocular skin.periocular skin.
Mild-to-Moderate Chemical BurnsMild-to-Moderate Chemical Burns
• Critical signs:Critical signs:Pronounced Pronounced
chemosis and chemosis and
perilimbal blanchingperilimbal blanching
Corneal edema and Corneal edema and
opacificationopacification
Moderate-to-Severe Chemical BurnsModerate-to-Severe Chemical Burns
• Other signs:Other signs:Increased IOCIncreased IOC
22ndnd & 3 & 3rdrd degree burns of degree burns of
the surrounding tissuethe surrounding tissue
Local necrotic retinopathyLocal necrotic retinopathy
Moderate-to-Severe Chemical BurnsModerate-to-Severe Chemical Burns
Treatment :Treatment :
IrrigationIrrigation
AntibioticsAntibiotics
Artificial tearArtificial tear
SteroidsSteroids
Ascorbic acidAscorbic acid
Calcium gluconateCalcium gluconate
dilating eye dropdilating eye drop
Complications :Complications :
ScaresScares
GlaucomaGlaucoma
BlindnessBlindness
Physical traumaPhysical trauma
• Corneal abrasionCorneal abrasion
Illinois EMSC31
Corneal lacerationCorneal laceration
Foreign BodyForeign Body
• Symptoms:Symptoms: Foreign-body sensationForeign-body sensation
TearingTearing
Blurred visionBlurred vision
PhotophobiaPhotophobia
Commonly, a history of a Commonly, a history of a
foreign bodyforeign body
Corneal Foreign BodyCorneal Foreign Body
Penetrating ocular injuryPenetrating ocular injury
• Incidence : 1.4%-4%Incidence : 1.4%-4%
• Industries at Greatest risk: construction; manufacturingIndustries at Greatest risk: construction; manufacturing
• Object: metal fragment ;glass; nail Object: metal fragment ;glass; nail
• Sign:Sign:
• Flat eyeFlat eye
• Low visionLow vision
• Low intraocular pressureLow intraocular pressure
• hyphemahyphema
Foreign BodyForeign Body
متالیک : • متالیک : نمکهای نمکهای
برگشت : • غیرقابل توکسیک آسیب سبب مس و آهن برگشت : نظیر غیرقابل توکسیک آسیب سبب مس و آهن نظیر
شبکیه شبکیه در در
• : محلول کمتر : مواد محلول کمتر مواد
دارند • بهتری پروگنوز ،شیشه پالستیک دارند آلومینیم، بهتری پروگنوز ،شیشه پالستیک آلومینیم،
• : ارگانیک خارجی : اجسام ارگانیک خارجی اجسام
مشکل • بسیار درمان با چشمی داخل عفونت سبب مشکل چوب بسیار درمان با چشمی داخل عفونت سبب چوب
بد پروگنوز بد و پروگنوز و
RadiationRadiation ::
UV < 400 nmUV < 400 nm
IR > 700 nmIR > 700 nm
Visible 400 Visible 400 –– 700 nm 700 nm
Ionising <0.0001 nmIonising <0.0001 nm
ELF 1000 - 10000 Km ELF 1000 - 10000 Km
Electromagnetic SpectrumElectromagnetic Spectrum
Radio Micro I.R. Visible U.V. X-ray -ray
104 106 1010 1013 1023Hz
UV Sources :UV Sources :
SunSun
WeldingWelding
LampsLamps
FoundryFoundry
Blacksmitch Blacksmitch
• UV-CUV-C:100-290nm:does not normally :100-290nm:does not normally
penetrate the earth atomospherpenetrate the earth atomospher
• UV-BUV-B:290-320 nm: cortical cataract; :290-320 nm: cortical cataract;
petrygium;petrygium; photokeratit; intraocular photokeratit; intraocular
melanoma??melanoma??
• UV-AUV-A:320-400nm: petrygium:320-400nm: petrygium
Infra Infra Red Red
IR - A : 780 IR - A : 780 –– 1400 nm 1400 nm
IR IR –– B : 1400 B : 1400 –– 3000 nm 3000 nm
IR IR –– C : 3000 - 10000 nm C : 3000 - 10000 nm
•All form of cataractAll form of cataract
•Pathagnomonic: exfoliative or splitting Pathagnomonic: exfoliative or splitting
of anterior lens capsuleof anterior lens capsule
IRIR sources : sources :SunSunHeatersHeatersSteel IndustrySteel IndustryGlass IndustryGlass IndustryLasers YAG - Neodymium - CO2Lasers YAG - Neodymium - CO2LampsLampsWeldingWelding
IRIR absorption in Eye : absorption in Eye :Cornea : IR-C IR-B
Lens : IR-A
Retina : IR-A
As shorter wave length more heat
production
Causes of occupational cataracts Causes of occupational cataracts ::microwaves,microwaves,
TNTTNT
, ionizing radiation, ionizing radiation
, infrared radiation, , infrared radiation,
naphthalene, dinitrophenol, naphthalene, dinitrophenol,
dinitrol-o-cresol,dinitrol-o-cresol,
ethylene oxide. ethylene oxide.
• Intense exposure to UV light Intense exposure to UV light
in the 295-320 nm range can in the 295-320 nm range can
cause cataracts that usually cause cataracts that usually
appear within 24 happear within 24 h
• "X-ray radiation in a dose of "X-ray radiation in a dose of
500-800 R directed toward the 500-800 R directed toward the
lens surface can cause lens surface can cause
cataracts, cataracts,
Laser eye damageLaser eye damage
a short introduction
http://www.adm.uwaterloo.ca/infohs/lasermanual/documents/section11.html
The majority of injuries involve the eye and, to a lesser extent, the skin
Summary of reported laser accidents in the United States and their causes from 1964 to 1992
Exposure Limits – Laser ClassificationExposure Limits – Laser Classification
Class 1 Lasers
Class 1 lasers do not emit harmful levels of radiation .
Class 2 Lasers
Capable of creating eye damage through chronic exposure. In general, the human eye will blink within 0.25 second when exposed to Class 2 laser light, providing adequate protection. It is possible to stare into a Class 2 laser long enough to cause damage to the eye.
At LCVU we use almost exclusively Class 3 and Class 4 lasers!
Class 3a Lasers (1-5 mW)
Not hazardous when viewed momentarily with the naked eye, but they pose severe eye hazards when viewed through optical instruments (e.g., microscopes and binoculars).
Class 3b Lasers (5-500 mW )
Injury upon direct viewing of the beam and specular reflections. Specific control measures must be implemented.
Class 4 Lasers (> 500 mW )They pose eye hazards, skin hazards, and fire hazards. Viewing of the beam and of specular reflections or exposure to diffuse reflections can cause eye and skin injuries. All control measures to be outlined must be implemented.
Exposure Limits – Laser ClassificationExposure Limits – Laser Classification
The effects of the laser depends strongly on the The effects of the laser depends strongly on the wavelengthwavelength
http://www.adtdl.army.mil/cgi-bin/atdl.dll/fm/8-50/INTRO.htm
The biological damage caused by lasers is produced through thermal, acoustical and photochemical processes.
Thermal effects are caused by a rise in temperature following absorption of laser energy. The severity of the damage is dependent upon several factors, including exposure duration, wavelength of the beam, energy of the beam, and the area and type of tissue exposed to the beam.
The most likely effect of intercepting a laser beam with the eye is a thermal burn which destroys the retinal tissue. Since retinal tissue does not regenerate, the damage is permanent.
Potential eye damagePotential eye damage
Acoustical effects result when laser pulses with a duration less than 10 microseconds induce a shock wave in the retinal tissue which causes a rupture of the tissue. This damage is permanent, as with a retinal burn.Acoustic damage is actually more destructive than a thermal burn. Acoustic damage usually affects a greater area of the retina, and the threshold energy for this effect is substantially lower.
Potential eye damagePotential eye damage
Beam exposure may also cause Photochemical effects when photons interact with tissue cells. A change in cell chemistry may result in damage or change to tissue. Photochemical effects depend strongly on wavelength.
the severity of the eye damage depends strongly on whether it occurs by intrabeam exposure or scattered laser light
Potential eye damagePotential eye damage
http://www.adtdl.army.mil/cgi-bin/atdl.dll/fm/8-50/INTRO.htm
Example of eye damageExample of eye damage
Experience has demonstrated that most laser injuries go unreported for 24–48 hours by the injured person. This is a critical time for treatment of the injury.