بسم الله الرحمن الرحیم

1. بسم الله الرحمن الرحیم

2. Occupational eye disorders By :SotoudehManeshMD

3. Important Ergophthalmology USA:1.4 million injury&illnessin2002 - 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

4. Two General Types of Vision andEye Assessments Can Be Differentiated • 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 — Examines subjects for eye disorders and diseases — Diagnoses eye disorders and diseases — Prescribes treatment Source: Prevent Blindness America

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

6. Visual acuity Snellen chart Acuity at Near&Distance

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

8. Visual field Confrontation test primetry

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

10. 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). Color blindness The different kinds of inherited color blindness result from partial or complete loss of function of one or more of the different cone systems.

11. 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. • Total color blindness • Dichromacy: occurs when only one of the cone pigments is missing and color is reduced to two dimensions. • Partial color blindness red-green blue-yellow

12. Dichromacy

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

14. Colour vision test Ishihara plates

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

16. 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 , Advantages of binocular vision over monocular • The presence of stereopsis , improved visual acuity , an enlarged Field of peripheral vision , slightly brighter of object

17. Clinical tests for stereopsis Contour stereotest • Titmusstereotest Random dot stereotest • Frisby test • Random Dot-E test

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

20. Occupational EYE Illness EYE injuries EYE Diseases

21. EYE Chemical Burns Alkali burns Acid burns Irritants

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

23. Alkali Burns Sodium hydroxide Potassium hydroxide Amonia Cement Lye Detergents

24. Emergency • Treatment should be immediate, even before making vision tests! • Premedicate with proparacaine or tetracaine. • Copious irrigation: LR or NS X 30 min. • Wait 5 minutes and check pH. If not normal, repeat.

25. Mild-to-Moderate Chemical Burns • Critical signs • Corneal epithelial defects range from scattered superficial punctatekeratitis (SPK) to focal epithelial loss to sloughing of the entire epithelium

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

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

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

29. Treatment : Irrigation Antibiotics Artificial tear Steroids Ascorbic acid Calcium gluconate dilating eye drop

30. Complications : Scares Glaucoma Blindness

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

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

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

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

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

36. Electromagnetic Spectrum -ray Radio Micro I.R. Visible U.V. X-ray 104 106 1010 1013 1023 Hz

39. UV Sources : UV-C:100-290nm:does not normally penetrate the earth atomospher UV-B:290-320 nm: cortical cataract; petrygium;photokeratit; intraocular melanoma?? UV-A:320-400nm: petrygium Sun Welding Lamps Foundry Blacksmitch

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

42. IR sources : Sun Heaters Steel Industry Glass Industry Lasers YAG - Neodymium - CO2 Lamps Welding

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

45. Causes of occupational cataracts : microwaves, TNT , ionizing radiation , infrared radiation, naphthalene, dinitrophenol, dinitrol-o-cresol, ethylene oxide. • 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,

46. Laser eye damage a short introduction

47. 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 http://www.adm.uwaterloo.ca/infohs/lasermanual/documents/section11.html

48. 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!

49. 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

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