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Effects of radiation
and glare in eye
Hira Nath Dahal
Optometrist
Drishti Eye Care System
Radiation
• Physical term defining the transfer of energy through space from and
emitter or radiator to a receiver
• Light emission and absorption
• Net transfer of energy
10/06/17 3
Electromagnetic Spectrum
10/06/17 4
Electromagnetic Spectrum
FG Figure 7-2
ULTRA-
VIOLET
RADIATION
10/06/17 5
Electromagnetic Spectrum
FG Figure 7-2
ULTRA-
VIOLET
RADIATION
INFRARED
RADIATION
Radiation effects
• Mechanism of radiation hazards
• Molecular level
• Photo-absorption increased energy level unstable state  electron ejection 
combine with oxygen  superoxide molecule formation (free radical)disrupt cell
membrane, mitochondrial membrane and nucleic acid  tissue destruction
• Tissue level
Classification of radiation effects
• Draper’s law
• For an effect the radiation must be absorbed by the substance
• Vision??
• Effects of radiation
• Ionizing radiation
• Non-ionizing radiation
Ionizing radiation
• Interacts with matter to form ions
• High-energy electromagnetic radiation and particle radiation are
capable of producing ions in their passage through matter.
• Types
• Alpha and beta particles,
• X-rays, gamma rays
• Ionizing radiation thorough living tissue  wreaks havoc on the atoms
and molecules in its path  chain of events  destruction of living cells
with functional abnormality
Ionizing radiation: Effects
• Damage depends on
• Exposure time
• Concentration
• Type
• Direct effect
• Cellular anomalies or death
• Indirect effect
• Damage to blood vessels
• Low levels of radiation
• Engorged conjunctival vessels
• Loss of corneal lusture
• High levels of radiation
• Exfoliation of epithelial cells
• Keratitis
• Corneal ulcer
• Cataract
• Retinal degeneration
Non-ionizing radiation
• Electromagnetic radiation that is not of sufficient energy to
ionize matter, though it is capable of damaging the human body.
• Cause photochemical and thermal effects
• By exciting electrons in atoms to higher energy levels, and by
producing molecular excitation.
• Examples
• Lasers, radio-frequency and microwave radiation, IR radiation,
and UV radiation
Non-ionizing radiation: Effects
•Thermal effects
• Heating effect
• Solar retinopathy
•Photochemical effects
• Visual sensation
• Photokeratitis
Concentration of radiant energy by eye
Special consideration
Absorption of the radiation by the ocular
tissue
Tissue Ultraviolet (nm) Visible (nm) Infrared (nm)
Tear layer 290-380 380-760 760-3000
Cornea 290-380℗ 380-760 760-3000℗
Aqueous 290-380℗ 380-760 760-3000℗
Lens in child 310-380℗ 380-760 760-2500℗
Lens in adult 375-380℗ 380-760℗ 760-2500℗
Vitreous 290-380℗ 380-760 760-1600℗
Absorption of radiation by various ocularAbsorption of radiation by various ocular
tissuestissues
Effect of ultraviolet radiation (UVR)
•Pinguecula
• Small yellowish elevated concretion of bulbar conjunctiva
• Fibro-fatty degenerative change within the palpebral fissure
• Typically located nasally
• Due to light reflecting off the nose onto the nasal conjunctiva
• a/w long continued exposure to the solar radiation
Pterygium
 A fibrovascular growth which appears on the
cornea and looks as if it is continuous with the
conjunctiva
◦ ?Degeneration or proliferation
◦ Rich in blood vessel growth which appears to pull the
lesion toward he cornea.
◦ An orange-brown ferric deposition line (Stocker’s line)
may be seen at the leading edge of the pterygium on
the cornea
 More on nasal side
Pterygium
 Greater frequency in tropical areas near the equator rather than in
milder climates
◦ UVR as an risk factor
 Pathophysiology
◦ Elastoid degeneration of deep conjunctival tissue
◦ fibrovascular proliferation
◦ over growth of conjunctivally derived epithelium onto the limbus and
cornea
Band shaped keratopathy
 White or cream colored opacities b/w the
epithelium and Bowmann’s layer
◦ Distributed symmetrically in the inter-
palpebral portions of two cornea
 Spheroid degeneration or climatic droplet
keratopathy
 Limited geographic prevalence
Photophthalmia
◦ Absorption of UV<300 nm
◦ Photochemical damage to corneal epithelium
◦ Photokeratoconjuctivitis
◦ Latent periods of 30 minutes to 24 hrs
◦ Cumulative effects
◦ Intermittent exposure prevents healing
Photophthalmia
 Clinical features
◦ Foreign body sensation
◦ Photophobia
◦ Lacrimation and blepharospasm
◦ Redness
◦ Edema
◦ Similar features as in snow blindness
and welder’s keratitis
• Self limiting
• Symptomatic treatment
• antibiotic coverage
• NSAIDS
Uveitis
• UV wavelengths between 295nm and 310nm cause anterior
uveitis.
• Usually this is only a temporary problem.
Cataract
 Any form of lens opacity
◦ Adversely affecting vision or visual function
 Continuous exposure
 Cumulative effect
◦ Formation of lens pigments causing yellow coloration of the lens
nucleus
◦ Pigments mainly produced by the nucleus
◦ UV-B (290-320)
◦ Brown cataract
 Nuclear, PSCC and cortical cataract
Retinal damage
 Usually protected
◦ ? aphakia
 UVR absorption by RPE and choroid  potential photochemical
and thermal effect
 Cystoid macular edema
 Decline in short wavelength sensitive cones in rapid manner
 Retinal degenerative changes
◦ ARMD
Age related macular degeneration
• Prolonged sun exposure: risk factor
Tumors of eyelids and conjunctiva
• Basal cell carcinoma
• Mainly lower lids on medial sides
• More incidence in the countries with high sunlight
exposure (Australia)
• Squamous cell carcinoma
• Invasive epithelial malignancy showing keratinocytic
differntiation
• Lower lid
Tumors of eyelids and conjunctiva
• Sebaceous carcinoma
• Malignant melanoma
• Squamous cell carcinoma of the conjunctiva
Effects of visible radiation
 Transparent media
◦ Transmisssion of the visible spectrum
 Photoreceptors
◦ Absorption  visual sensation
 Higher level of visible light
◦ Harmful photochemical and thermal injury to the retina
◦ Converged radiation to the retina
◦ Even at normal level, prolonged exposure  undesirable visual effects such
as increased dark adaptation time
Effects of visible radiation
• Short wavelength
• Higher energy more photochemical damage
• Long wavelength
• Less energy  both photochemical and thermal damage
• Infra-red radiation thermal damage
Effects of visible radiation
• Age related macular degeneration
• Long term exposure to the visible radiation and UVR
• RPE and photoreceptor damage
•Solar retinopathy
•Eclipse burn
•Presentation
• Reduced vision
• Small dense central scotoma
• Chromatopsia and metamorphopsia
Effects of visible radiation
•Solar retinopathy
• Cause
• ?IR thermal burn
• Photochemical trauma (blue light hazard)- short term
exposure to the high energy short wavelength visible
spectrum (400-500nm)
• Thermal injury - Long term exposure to the long
wavelength visible radiation and IR radiation
Solar retinopathy
Effects of IR radiation
 Damage by 780-2000 nm
 >1400 nm absorbed by tear film and cornea
 Sources
◦ Solar radiation
◦ Carbon, tungsten and xenon lamps
◦ Photoflood lamps
◦ Some laser sources
 Immediate effects after IR exposure
 Population at risk
◦ Glass blowers
◦ Blast furnace operators
Effects of IR radiation
 Cornea
◦ Coagulation and opacification
 Iris
◦ Congestion
◦ Depigmentation
◦ Atrophy
 Lens
◦ Exfoliation of lens capsule
◦ Coagulation of lens protein
◦ Cataract production : ASCC, PSCC
 Retina
◦ Necrotic burns
Other forms of radiation
• Long wave microwaves
• Diathermy
• Ionizing radiation
• X-ray and gamma rays
Glare
 Refers to the presence of one or more areas in the field of vision
that are of sufficient brightness to cause discomfort in vision.
 Visual perception created by external light
 Glare source : Axial / Peripheral
 Reduces the quality of the image
◦ an unpleasant sensation
◦ a temporary blurring of vision
◦ a feeling of ocular fatigue
Classification
• Veiling or disability glare
• Discomfort glare
• Specular reflection glare
Veiling or disability galre
 Arises from stray light falling on the retina, usually from scatter
by the media of the eye.
 Scattered light falls as a patch of veiling illuminance on the fovea
◦ Reduces the contrast of the retinal image.
◦ Reduces visibility and visual performance.
 E.g. sky, sand, brightly illuminated walls etc.-
◦ the reflected images are large in angular subtense leading to reduction
in contrast observed in the visual field.
Glare in Cataract
Normal Cataract
Discomfort glare
• Occurs when the illumination in a part of the visual field is
much greater than the level of illumination for which the
retina is adapted.
• Highest level of illumination in the visual field and background
illumination exceeds a ratio of 3 :1
• During night driving-causes extreme discomfort.
• Importance of having background illumination while
watching television
Specular reflection glare
 Occurs when patches of bright light are
reflected form smooth, shiny surface into the
eye.
◦ Typical reflecting surfaces include expanses of
water, snowfields, roadways etc.
 Reflections are not only annoying but
interfere with visibility, at times seriously.
 Can be well controlled by using polaroid
glasses.
Glare testing
•Objective :
• quantify the deleterious effects of light scatter on visual
performance
• Reduce the effect on impairment of vision
•When?
• Corneal opacities
• Corneal dystrophies/ Degeneration
• Cataract
Indications for glare testing
 Pre-operative
◦ Cornea
 Infectious scarring
 Traumatic scarring
 Degenerative scarring
 Dystrophic scarring
◦ Lens
 Age-related cataract
 Traumatic cataract
 Drug-induced cataract
 Disease-induced cataract
 Post-operative
◦ Cornea
 PK
 Epikeratophakia
 Keratomileusis
 Repaired laceration
◦ Lens
 PCO following ECCE, IOL
Glare Testers
• Brightness Acuity Tester (BAT)
• Optec 1500 Glare Tester
• Terry Vision Analyzer (TVA)
• Miller-Nadler Glare Tester
Thank you

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Effects of radiation and glare in eye

  • 1. Effects of radiation and glare in eye Hira Nath Dahal Optometrist Drishti Eye Care System
  • 2. Radiation • Physical term defining the transfer of energy through space from and emitter or radiator to a receiver • Light emission and absorption • Net transfer of energy
  • 4. 10/06/17 4 Electromagnetic Spectrum FG Figure 7-2 ULTRA- VIOLET RADIATION
  • 5. 10/06/17 5 Electromagnetic Spectrum FG Figure 7-2 ULTRA- VIOLET RADIATION INFRARED RADIATION
  • 6. Radiation effects • Mechanism of radiation hazards • Molecular level • Photo-absorption increased energy level unstable state  electron ejection  combine with oxygen  superoxide molecule formation (free radical)disrupt cell membrane, mitochondrial membrane and nucleic acid  tissue destruction • Tissue level
  • 7. Classification of radiation effects • Draper’s law • For an effect the radiation must be absorbed by the substance • Vision?? • Effects of radiation • Ionizing radiation • Non-ionizing radiation
  • 8. Ionizing radiation • Interacts with matter to form ions • High-energy electromagnetic radiation and particle radiation are capable of producing ions in their passage through matter. • Types • Alpha and beta particles, • X-rays, gamma rays • Ionizing radiation thorough living tissue  wreaks havoc on the atoms and molecules in its path  chain of events  destruction of living cells with functional abnormality
  • 9. Ionizing radiation: Effects • Damage depends on • Exposure time • Concentration • Type • Direct effect • Cellular anomalies or death • Indirect effect • Damage to blood vessels • Low levels of radiation • Engorged conjunctival vessels • Loss of corneal lusture • High levels of radiation • Exfoliation of epithelial cells • Keratitis • Corneal ulcer • Cataract • Retinal degeneration
  • 10. Non-ionizing radiation • Electromagnetic radiation that is not of sufficient energy to ionize matter, though it is capable of damaging the human body. • Cause photochemical and thermal effects • By exciting electrons in atoms to higher energy levels, and by producing molecular excitation. • Examples • Lasers, radio-frequency and microwave radiation, IR radiation, and UV radiation
  • 11. Non-ionizing radiation: Effects •Thermal effects • Heating effect • Solar retinopathy •Photochemical effects • Visual sensation • Photokeratitis
  • 12. Concentration of radiant energy by eye
  • 14. Absorption of the radiation by the ocular tissue Tissue Ultraviolet (nm) Visible (nm) Infrared (nm) Tear layer 290-380 380-760 760-3000 Cornea 290-380℗ 380-760 760-3000℗ Aqueous 290-380℗ 380-760 760-3000℗ Lens in child 310-380℗ 380-760 760-2500℗ Lens in adult 375-380℗ 380-760℗ 760-2500℗ Vitreous 290-380℗ 380-760 760-1600℗
  • 15. Absorption of radiation by various ocularAbsorption of radiation by various ocular tissuestissues
  • 16. Effect of ultraviolet radiation (UVR) •Pinguecula • Small yellowish elevated concretion of bulbar conjunctiva • Fibro-fatty degenerative change within the palpebral fissure • Typically located nasally • Due to light reflecting off the nose onto the nasal conjunctiva • a/w long continued exposure to the solar radiation
  • 17. Pterygium  A fibrovascular growth which appears on the cornea and looks as if it is continuous with the conjunctiva ◦ ?Degeneration or proliferation ◦ Rich in blood vessel growth which appears to pull the lesion toward he cornea. ◦ An orange-brown ferric deposition line (Stocker’s line) may be seen at the leading edge of the pterygium on the cornea  More on nasal side
  • 18. Pterygium  Greater frequency in tropical areas near the equator rather than in milder climates ◦ UVR as an risk factor  Pathophysiology ◦ Elastoid degeneration of deep conjunctival tissue ◦ fibrovascular proliferation ◦ over growth of conjunctivally derived epithelium onto the limbus and cornea
  • 19. Band shaped keratopathy  White or cream colored opacities b/w the epithelium and Bowmann’s layer ◦ Distributed symmetrically in the inter- palpebral portions of two cornea  Spheroid degeneration or climatic droplet keratopathy  Limited geographic prevalence
  • 20. Photophthalmia ◦ Absorption of UV<300 nm ◦ Photochemical damage to corneal epithelium ◦ Photokeratoconjuctivitis ◦ Latent periods of 30 minutes to 24 hrs ◦ Cumulative effects ◦ Intermittent exposure prevents healing
  • 21. Photophthalmia  Clinical features ◦ Foreign body sensation ◦ Photophobia ◦ Lacrimation and blepharospasm ◦ Redness ◦ Edema ◦ Similar features as in snow blindness and welder’s keratitis • Self limiting • Symptomatic treatment • antibiotic coverage • NSAIDS
  • 22. Uveitis • UV wavelengths between 295nm and 310nm cause anterior uveitis. • Usually this is only a temporary problem.
  • 23. Cataract  Any form of lens opacity ◦ Adversely affecting vision or visual function  Continuous exposure  Cumulative effect ◦ Formation of lens pigments causing yellow coloration of the lens nucleus ◦ Pigments mainly produced by the nucleus ◦ UV-B (290-320) ◦ Brown cataract  Nuclear, PSCC and cortical cataract
  • 24. Retinal damage  Usually protected ◦ ? aphakia  UVR absorption by RPE and choroid  potential photochemical and thermal effect  Cystoid macular edema  Decline in short wavelength sensitive cones in rapid manner  Retinal degenerative changes ◦ ARMD
  • 25. Age related macular degeneration • Prolonged sun exposure: risk factor
  • 26. Tumors of eyelids and conjunctiva • Basal cell carcinoma • Mainly lower lids on medial sides • More incidence in the countries with high sunlight exposure (Australia) • Squamous cell carcinoma • Invasive epithelial malignancy showing keratinocytic differntiation • Lower lid
  • 27. Tumors of eyelids and conjunctiva • Sebaceous carcinoma • Malignant melanoma • Squamous cell carcinoma of the conjunctiva
  • 28. Effects of visible radiation  Transparent media ◦ Transmisssion of the visible spectrum  Photoreceptors ◦ Absorption  visual sensation  Higher level of visible light ◦ Harmful photochemical and thermal injury to the retina ◦ Converged radiation to the retina ◦ Even at normal level, prolonged exposure  undesirable visual effects such as increased dark adaptation time
  • 29. Effects of visible radiation • Short wavelength • Higher energy more photochemical damage • Long wavelength • Less energy  both photochemical and thermal damage • Infra-red radiation thermal damage
  • 30. Effects of visible radiation • Age related macular degeneration • Long term exposure to the visible radiation and UVR • RPE and photoreceptor damage •Solar retinopathy •Eclipse burn •Presentation • Reduced vision • Small dense central scotoma • Chromatopsia and metamorphopsia
  • 31. Effects of visible radiation •Solar retinopathy • Cause • ?IR thermal burn • Photochemical trauma (blue light hazard)- short term exposure to the high energy short wavelength visible spectrum (400-500nm) • Thermal injury - Long term exposure to the long wavelength visible radiation and IR radiation
  • 33. Effects of IR radiation  Damage by 780-2000 nm  >1400 nm absorbed by tear film and cornea  Sources ◦ Solar radiation ◦ Carbon, tungsten and xenon lamps ◦ Photoflood lamps ◦ Some laser sources  Immediate effects after IR exposure  Population at risk ◦ Glass blowers ◦ Blast furnace operators
  • 34. Effects of IR radiation  Cornea ◦ Coagulation and opacification  Iris ◦ Congestion ◦ Depigmentation ◦ Atrophy  Lens ◦ Exfoliation of lens capsule ◦ Coagulation of lens protein ◦ Cataract production : ASCC, PSCC  Retina ◦ Necrotic burns
  • 35. Other forms of radiation • Long wave microwaves • Diathermy • Ionizing radiation • X-ray and gamma rays
  • 36. Glare  Refers to the presence of one or more areas in the field of vision that are of sufficient brightness to cause discomfort in vision.  Visual perception created by external light  Glare source : Axial / Peripheral  Reduces the quality of the image ◦ an unpleasant sensation ◦ a temporary blurring of vision ◦ a feeling of ocular fatigue
  • 37. Classification • Veiling or disability glare • Discomfort glare • Specular reflection glare
  • 38. Veiling or disability galre  Arises from stray light falling on the retina, usually from scatter by the media of the eye.  Scattered light falls as a patch of veiling illuminance on the fovea ◦ Reduces the contrast of the retinal image. ◦ Reduces visibility and visual performance.  E.g. sky, sand, brightly illuminated walls etc.- ◦ the reflected images are large in angular subtense leading to reduction in contrast observed in the visual field.
  • 40. Discomfort glare • Occurs when the illumination in a part of the visual field is much greater than the level of illumination for which the retina is adapted. • Highest level of illumination in the visual field and background illumination exceeds a ratio of 3 :1 • During night driving-causes extreme discomfort. • Importance of having background illumination while watching television
  • 41. Specular reflection glare  Occurs when patches of bright light are reflected form smooth, shiny surface into the eye. ◦ Typical reflecting surfaces include expanses of water, snowfields, roadways etc.  Reflections are not only annoying but interfere with visibility, at times seriously.  Can be well controlled by using polaroid glasses.
  • 42. Glare testing •Objective : • quantify the deleterious effects of light scatter on visual performance • Reduce the effect on impairment of vision •When? • Corneal opacities • Corneal dystrophies/ Degeneration • Cataract
  • 43. Indications for glare testing  Pre-operative ◦ Cornea  Infectious scarring  Traumatic scarring  Degenerative scarring  Dystrophic scarring ◦ Lens  Age-related cataract  Traumatic cataract  Drug-induced cataract  Disease-induced cataract  Post-operative ◦ Cornea  PK  Epikeratophakia  Keratomileusis  Repaired laceration ◦ Lens  PCO following ECCE, IOL
  • 44. Glare Testers • Brightness Acuity Tester (BAT) • Optec 1500 Glare Tester • Terry Vision Analyzer (TVA) • Miller-Nadler Glare Tester