2. بسم الله الرحمن الرحیم

3. MD By :Sotoudeh Manesh MD Occupational eye disorders

4. ImportantErgophthalmology USA:1.4 million injury &illness in2002 - 47% of all head injury - ocular foreign body:38% - contusion/abrasion:27% - burn:12% - conjectivitis:11% Non-construction>welder>cutter>truck driver - 4%workers compensation claim &1%total paymnt

5. Two General Types of Vision and Eye Assessments Can Be Differentiated Screening Screening — Identifies those at high risk or in need of a professional examination — May detect disorders in early, treatable stage — Provides public with valuable information and education about eye care — Results in referral to an eye care professional or primary care provider Examination Examination — Examines subjects for eye disorders and diseases — Diagnoses eye disorders and diseases — Prescribes treatment Source: Prevent Blindness America

6. Components Of Vision Screening History and symptoms Visual acuity at any distance Visual field Colour vision Depth perception Contrast sensitivity

7. Visual acuity Snellen chart Acuity at Near&Distance

8. Near visual acuity Definition Definition  The ability to see clearly at a normal reading distance Method of measuring Method of measuring  Jaeger card-reduced snellen chart Causes of decreased near V.A in the presence of normal distance V.A Causes of decreased near V.A in the presence of normal distance V.A  Presbyopia,uncorrected hyperopia,centerally located cataracts and drug side effects located cataracts and drug side effects

9. Visual field Confrontation test primetry

10. Visual field Normal extension Normal extension  70 degrees Inferiorly, 60 degrees superiorly,95 degrees temporally and 60 degrees nasally. Total horizontal visual field extent to 190 degrees Total horizontal visual field extent to 190 degrees Factors that influence the visual field Factors that influence the visual field  Size, distance, background illumination, colour, Kind of job, Bi or monocular vision, age, use of Kind of job, Bi or monocular vision, age, use of Personal protective device ( safety spectacle) Personal protective device ( safety spectacle)

11. Color blindness Normally, there are three kinds of cones (each one sensitive to a specific range of wavelengths): "red" cones (64%) "green" cones (32%) "blue" 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.

12. Different Types of Color Blindness Monochromacy: occurs when two or all three of the cone pigments are missing and color and lightness vision is reduced to one dimension. Monochromacy: occurs when two or all three of the cone pigments are missing and color and lightness vision is reduced to one dimension.  Total color blindness Dichromacy: occurs when only one of the cone pigments is missing and color is reduced to two dimensions. Dichromacy: occurs when only one of the cone pigments is missing and color is reduced to two dimensions.  Partial color blindness red-greenblue-yellow

13. Dichromacy

14. Photoreceptor Anatomy Example: if you stimulate all 3 types of cones about equally the result is white or no color. Example: if you stimulate all 3 types of cones about equally the result is white or no color.

15. Colour vision test Ishihara plates

16. Colour vision deficiency in wokplace Styrene Styrene Toluene Toluene Perchloroethylene Perchloroethylene Carbon disulfide Carbon disulfide Metallic mercurry Metallic mercurry Mercury vappor Mercury vappor n-hexan n-hexan

17. Depth perception (Stereopsis)  The ability to precieve depth or relative distance Some jobs that need stereoscopic vision  Furk-lift truck operator, crane driver, pilot,… Factors that influence depth perception  Uncorrected refractive errores, amblyopia, squint low level of illumination, anisometropia, age, low level of illumination, anisometropia, age, Advantages of binocular vision over monocular  The presence of stereopsis, improved visual acuity, an enlarged Field of peripheral vision, slightly brighter of object Field of peripheral vision, slightly brighter of object

18. Clinical tests for stereopsis Contour stereotest  Titmus stereotest Random dot stereotest  Frisby test  Random Dot-E test

19. Clinical Contrast Sensitivity Tests Pelli-Robson chart Pelli-Robson chart Regan low-contrast Regan low-contrast Vistech chart Vistech chart Melbourne edge test Melbourne edge test

21. Occupational EYE Illness EYE injuries EYE Diseases

22. EYE Chemical Burns 1. Alkali burns 2. Acid burns 3. Irritants

23. Eye Acid Burns Sulfuric acid Nitric acid Chlorohydric acid Hipochloric acid Perchloric acid Flurohydric acid Cholor So2 So3 No2 N2o4 ?

24. Alkali Burns Sodium hydroxide Potassium hydroxide AmoniaCementLyeDetergents

25. Emergency Treatment should be immediate, even before making vision tests! Treatment should be immediate, even before making vision tests! Premedicate with proparacaine or tetracaine. Premedicate with proparacaine or 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 normal, repeat. Wait 5 minutes and check pH. If not normal, repeat.

26. Mild-to-Moderate Chemical Burns Critical signs Critical signs  Corneal epithelial defects range from scattered superficial punctate keratitis (SPK) to focal epithelial loss to sloughing of the entire epithelium

27. Other Signs: Other Signs:  Focal area of conjunctival chemosis.  Hyperemia.  Mild eyelid edema.  Mild-anterior chamber reaction.  1 st or 2 nd degree burns to periocular skin. Mild-to-Moderate Chemical Burns

28. Critical signs: Critical signs:  Pronounced chemosis and perilimbal blanching  Corneal edema and opacification Moderate-to-Severe Chemical Burns

29. Other signs: Other signs:  Increased IOC  2 nd & 3 rd degree burns of the surrounding tissue  Local necrotic retinopathy Moderate-to-Severe Chemical Burns

30. Treatment : IrrigationAntibiotics Artificial tear Steroids Ascorbic acid Calcium gluconate dilating eye drop

31. Complications : ScaresGlaucomaBlindness

32. Physical trauma Corneal abrasion Corneal abrasion Illinois EMSC 31 Corneal laceration Foreign Body

33. Symptoms: Symptoms:  Foreign-body sensation  Tearing  Blurred vision  Photophobia  Commonly, a history of a foreign body Corneal Foreign Body

34. Penetrating ocular injury Incidence : 1.4%-4% Incidence : 1.4%-4% Industries at Greatest risk: construction; manufacturing Industries at Greatest risk: construction; manufacturing Object: metal fragment ;glass; nail Object: metal fragment ;glass; nail Sign: Sign: Flat eye Flat eye Low vision Low vision Low intraocular pressure Low intraocular pressure hyphema hyphema

35. Foreign Body نمکهای متالیک : نمکهای متالیک : نظیر آهن و مس :سبب آسیب توکسیک غیرقابل برگشت در شبکیه نظیر آهن و مس :سبب آسیب توکسیک غیرقابل برگشت در شبکیه مواد کمتر محلول: مواد کمتر محلول: آلومینیم، پلاستیک ،شیشه پروگنوز بهتری دارند آلومینیم، پلاستیک ،شیشه پروگنوز بهتری دارند اجسام خارجی ارگانیک: اجسام خارجی ارگانیک: چوب سبب عفونت داخل چشمی با درمان بسیار مشکل و پروگنوز بد چوب سبب عفونت داخل چشمی با درمان بسیار مشکل و پروگنوز بد

36. Radiation : UV < 400 nm IR > 700 nm Visible 400 – 700 nm Ionising <0.0001 nm ELF 1000 - 10000 Km

37. Electromagnetic Spectrum RadioMicroI.R.VisibleU.V.X-ray  -ray 10 4 10 610 10 13 10 23 Hz

40. UV Sources : SunWeldingLampsFoundryBlacksmitch UV-C:100-290nm:does not normally penetrate the earth atomospher UV-C:100-290nm:does not normally penetrate the earth atomospher UV-B:290-320 nm: cortical cataract; petrygium; photokeratit; intraocular melanoma?? UV-B:290-320 nm: cortical cataract; petrygium; photokeratit; intraocular melanoma?? UV-A:320-400nm: petrygium UV-A:320-400nm: petrygium

42. Infra Red IR - A : 780 – 1400 nm IR – B : 1400 – 3000 nm IR – C : 3000 - 10000 nm All form of cataract All form of cataract Pathagnomonic: exfoliative or splitting of anterior lens capsule Pathagnomonic: exfoliative or splitting of anterior lens capsule

43. IR sources : SunHeaters Steel Industry Glass Industry Lasers YAG - Neodymium - CO2 LampsWelding

44. IR absorption in Eye : Cornea : IR-C IR-B Lens : IR-A Retina : IR-A As shorter wave length more heat production

46. Causes of occupational cataracts : microwaves, TNT TNT, ionizing radiation, infrared radiation, naphthalene, dinitrophenol, dinitrol-o-cresol, ethylene oxide. ethylene oxide. Intense exposure to UV light in the 295-320 nm range can cause cataracts that usually appear within 24 h Intense exposure to UV light in the 295-320 nm range can cause cataracts that usually appear within 24 h "X-ray radiation in a dose of 500-800 R directed toward the lens surface can cause cataracts, "X-ray radiation in a dose of 500-800 R directed toward the lens surface can cause cataracts,

47. Laser eye damage a short introduction

48. 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

49. Exposure 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!

50. 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 Classification

51. The effects of the laser depends strongly on the wavelength http://www.adtdl.army.mil/cgi-bin/atdl.dll/fm/8-50/INTRO.htm

52. 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 damage

53. 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 damage

54. 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 damage

55. http://www.adtdl.army.mil/cgi-bin/atdl.dll/fm/8-50/INTRO.htm Example 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.