Occupational eye health in health care workers

Department of Ophthalmology

Christian Medical College

Vellore

Objectives

• Potential occupational eye injuries

• Potentially hazardous areas

• Hazard identification

• Surveillance system

• Personal protective equipment for eye

• Engineering checks

• Awareness capsules

• Eye safety policy

Why look at eye hazards

• Absenteeism

• Cataract

• Potentially blinding:

– Retinal burns

– Perforating eye injuries

– Severe chemical injuries

• ? Life threatening:

– Blood borne viral transmission through splashes

Questionnaire

• Work related eye injuries in your department

• What eye hazards

• How can it be reduced

• Do health care workers wear PPE for the eye at your place

• Do you have an eye safety policy

Epidemiology

• Eye injuries: 3- 4% of all occupational injuries*

*Xiang H, Stallones L, Chen G, Smith GA. Work-related eye injuries treated in hospital emergency departments in the US. Am J Ind Med. 2005 Jul; 48(1):57-62

Potential Hazards

• Physical Hazards

– Foreign Bodies / Missiles

– Radiation hazard

– Laser Induced damage

– Thermal

• Chemical hazards

• Biological hazard

– Infections

– Body fluid splashes

• Eye strain

PHYSICAL HAZARDS

DENTAL PROCEDURES

• Hazards: Aerosol splash (saliva and blood), flying debris

• Eye injuries: Ten % of occupational injuries to dental personnel 9 year period in a dental hospital.

• Eye protection compliance 57% when using laboratory cutting equipment.

British Dental Journal 2007; 203: E7; 1- 5

Optical shop : Spectacles lens CUTTING GRINDING

Engineering / Maintenance/ Non clinical support services

• Engineering controls

– E.g. machine guards

– Welding curtains for arc flash protection

• Administrative controls

– E.g. areas “off limits” for those uninvolved

• Proper protective eyewear

– Painting, breaking down

ELECTROMAGNETIC SPECTRUM

10 -14 10 -12 10 -10 10 -8 10 -6 10 -4 10 -2 1 10 2 10 4 10 6 10 8

Wavelength in Meters

10 10 10 8 10 6 10 4 10 2 1 10 -2 10 -4 10 -6 10 -8 10 -10 10 -12 10 -14

Broadcast

Short wave TV

FM

Radar Infrared

Near Far

Visible

Ultraviolet X Rays

Gamma Rays

Cosmic Rays Power

Transmission

Ionizing Radiation Nonionizing Radiation

Energy - Electron Volts High Low

LASER

RADIATION

Departments: Radiation Exposure

Department

Radio diagnosis

Radiotherapy

Nuclear Medicine

Cardiology

Operating Theaters

Gastroenterology

Orthopaedics

Haematology ((BMT)

Dental

Stem Cell

Transfusion Medicine

Dose Response Tissue

Examples of tissue Sensitivity

Very High White blood cells (bone marrow)

Intestinal epithelium

Reproductive cells

High Optic lens epithelium

Esophageal epithelium

Mucous membranes

Medium Brain – Glial cells

Lung, kidney, liver, thyroid,

pancreatic epithelium

Low Mature red blood cells

Muscle cells

Mature bone and cartilage

Radiation induced cataract

• Cataract – deterministic effect with threshold; may be even linear – no threshold

• An annual limit of 15 rem (0.15 Sv) to the lens of the eye

• Latency α 1 / Dose

Catheterization and Cardiovascular Interventions 76:826–834 (2010)

Protection

• Monitoring dose received

• Personal protective equipment

Management

Cataract Surgery Intraocular Lens Implantation

Light Amplification by Stimulated Emission of Radiation (LASER)

• Non Beam Hazards

– Electrical

– Explosion

– Compressed Gases

– Dyes and Solvents

– Fire

• Beam Hazards

American National Standards Institute (ANSI)

• Maximal Permissible Exposure – The maximum permissible exposure (MPE) is the

highest power or energy density (in W/cm2 or J/cm2) of a light source that is considered safe

• Nominal Ocular Hazard distance – distance from the source at which the intensity or the

energy per surface unit becomes lower than the MPE

• Nominal hazard Zone – space within which the level of direct, scattered or

reflected laser light emitted during laser operation exceeds the MPE

https://www.lia.org/PDF/Z136_1_s.pdf

Commonly used lasers TYPE Radiation type /

wavelength in nm Examples of application

Carbon dioxide (gas) Infra red (10600) Surgery

Argon (gas) Visible, blue (488), green (514)

Ophthalmology, Plastic Surgery

Krypton 532 (gas) Visible green (532) Surgery

Nd YAG (continuous wave, solid state)

Infrared (1064) General Surgery

Nd YAG (Q switched, solid state) Visible (632) Ophthalmology

Helium Neon (gas) Visible red (632) Alignment for aiming invisible beams

Ruby (solid) Visible red (694) Plastic Surgery, Dermatology

Rhodamine (dye) Visible red (630) Treatment of Malignancies

hwww.ccohs.ca/oshanswers/phys_agents/lasers.html

Laser - Biological effects in the eye

Spectral domain Wave length Eye (biological effects)

Ultraviolet B & C 200 – 315 nm Photokeratitis

Ultraviolet A 315 – 400 nm Photochemical cataract

Visible 400 -780 nm Photochemical and thermal retinal injury

Infrared A 780 – 1400 nm Cataract and retinal burn

Infrared B 1.4 to 3.0 microns Corneal burn, aqueous flare, cataract

Infrared C

3 to 1000 microns Corneal burn only

Clinical manifestations

Photokeratitis Foveal burn

Tear substitutes / rest Systemic / topical steroids

Factors • Types of beam:

– Direct :NEVER UNDER ANY CIRCUMSTANCES LOOK INTO ANY LASER BEAM

– Specular reflection

– Diffuse

• Class IV can initiate fire!

• Duration

– Less than 0.25 s safe BLINK

• Class 1, 2 A and 2 (direct)

• intrabeam or specular reflection viewing of Class 3a, 3b, or 4 or diffuse Class 4 happens before

• Class

– 1 : No danger

• E.g CD ROM players

– 2 : Direct viewing dangerous

• E.g Scanner at sales points

– 3: Direct and Specular

• E.g Medical

– 4. Serious hazard

• Research

Laser pointers

• Visible light

• Output power:

– 1 to 5 mW directly at eye,

– retinal irradiance similar

to that caused by staring directly at the sun

• blink reflex and aversion response.

• near 550 nm with less than 1 mW : safe

Laser retinal injury

PROTECTION

• Engineering controls : – Filters in machine

– Goggles

– Shutters /Key Switch /

• Avoid direct viewing

• Warning signs

MANAGEMENT

• Corticosteroids

• Rarely surgery

Thermal Hazards

• Central Sterilization Supplies department

• Injury

– Cell death - limited to the superficial epithelium;

– thermal necrosis and penetration can occur.

CHEMICAL HAZARDS

Chemical Hazards

• Vulnerable

– House keeping Staff

– Laboratory Personnel

– Preclinical teaching departments

– Service laboratories

– Personnel in the Operating room

• Responsible for 7% of work-related eye injuries treated at US hospital emergency departments.

• 60% of chemical injuries occur in workplace accidents

Chemical Injuries

• Potentially blinding in 1 in five

• Approx 15 % of severe injuries get functional vision

• Acids / alkalis, latter being worse

Anatomy

Transferring formalin from 40% container to another

container

Diluting the 40% formalin to make a solution of 10%

concentration

Lifting body out of formalin tank and transferring to a trolley and back

Management

• First Aid : Irrigate eye with sterile Balanced salt solution, ringer lactate or even tap water for 15 - 20 min ASAP

• Consult Ophthalmologist – Agent / pH

– Slit lamp examination

– Medical : Steroid / cycloplegic / anitbiotic / Vitamin C

– Surgical if extensive limbal stem cell loss

BIOLOGICAL HAZARDS

Infection

• Microbes : – Conjunctivitis (e.g.,

adenovirus, herpes simplex, Staphylococcus aureus)

– Systemic infections, including bloodborne viruses (e.g. hepatitis B and C viruses, human immunodeficiency virus), herpes viruses, and rhinoviruses.

• Mode of introduction to eye – Fomites

– directly (e.g., blood splashes, respiratory droplets generated during coughing or suctioning)

– touching the eyes with contaminated fingers or other objects : E.g microbiology labs)

Conjunctivitis

• Adenovirus (3, 7, 8, 19 serotypes) - nosocomial epidemic outbreaks

• Spread:

– Fomites / ophthalmic instruments

– Contaminated hand to surfaces

• Areas high risk

– Eye / staff clinics

– Neonatal ICU

– Long term facilities

SIGNS

Hemorrhagic: Enterovirus

Membranes

Visual blur : corneal involvement

PREVENTION

Preventive aspects- Conjunctivitis

• Epidemic potential, absenteeism, economic loss

• Delayed treatment in ophthalmology for primary disorders, secondary infections

• Infective as long as symptomatic (with discharge) up to two weeks

Identify

Educate

Treat

Isolate

Dispose

Reassure

CONTROL EPIDEMIC

Body Fluid splashes - EYE • Low risk of transmission

• Prophylaxis recommended

AREAS LIKELY

• Blood collection Areas

• Dialysis suites

• Operating room personnel

Body Fluid splashes

‘Eye Strain’: Computer vision syndrome

PREVENTION

• Ergonomics

• Breaks 20 min, 20 secs

• Tear Substitutes

HIGH RISK

• Radiology

• CHIPS

AWARENESS

Eye protection devices • Goggles

• Face protection Shields

• Safety glasses (polycarbonate)

• Full face respirators

• Prescription users : additional eyewear

• Z87 DEVICES

DO NOT

• rub when you suspect debris

• irrigate when suspecting perforation or foreign body

• use ordinary prescription glasses, reading glasses, sunglasses, and contact lenses instead of protective eyewear.

• work without appropriate spectacle correction: leads to injuries at workplace

Eye safety policy

• When must you wear PPE for eye

• What enforcement processes are in place

• How do you get help when there has been health care related eye injury

• How do you report

• How do you rectify lapse if any

Occupational Eye Injury Sustained eye injury

First Aid

Inform OSH team / SSHS

Eye consult

Manage

Preventive measure assess

/ set up

Awareness

Compliance

Monitoring

• Reporting system for eye

– Acute eg : splashes / missiles report to emergency

– Chronic eg radiation induced damage will need systems to be placed

• Preferably all acute eye injuries on the same line as needle stick

• Customize staff health checks on the basis of hazard risk in addition to general check up

Future plans

• Detailed eye hazard assessment

• Awareness capsules eg before the conjunctivitis season

• Mandatory staff training modules / CME

• Surveillance systems

• Baseline evaluation of departments with radiation for cataract

Eye safety checklist for health care

• Create a safe work environment – Indications

– Safety features of instruments in place and functional

– Workers educated on safe use

– Bystanders kept out e.g Laser sessions

• Identify – Primary Hazards

– Hazards posed by work happening on premises !!!

Eye safety checklist for health care

• Prevent injury/ Good work practices

– If PPE, Ensure good condition / fit / and availablility

– If procedure ensure availability of preventive preparation eg Sterilium

• Prepare for eye injuries esp chemical splashes

– Have sterile /appropriate solution for irrigation and equipment ready if necessary

Acknowledgements • Patients / Departments of Ophthalmology,

Anatomy, Dental and Orthopedics for the pictures