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Glare

Glare. Understanding and Assessing Glare: Minimize Discomfort and Maximize Visual Resolution Dr. Sandra Rosen. Poll: Who is with us today?. Lighting Considerations. Sufficient and diffuse is, of course, best But, ideal is not always possible in reality!. Lighting.

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Glare

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  1. Glare Understanding and Assessing Glare: Minimize Discomfort and Maximize Visual Resolution Dr. Sandra Rosen

  2. Poll: Who is with us today?

  3. Lighting Considerations Sufficient and diffuse is, of course, best But, ideal is not always possible in reality!

  4. Lighting • An often overlooked aspect of lighting is…Glare!! elibishop.com

  5. What is Glare? Glare is "the dazzling sensation of relatively bright light, which produces unpleas­antness or discomfort, or which interferes with optimum vision" (Cline. Hofstetter, & Griffin, 1989, p. 292).

  6. What Causes Glare? • Some types of glare affect all of us • Other types of glare are related to problems in the cornea, lens capsule, lens cortex, lens nucleus, vitreous, or retina.

  7. Sources of Glare • Reflective surfaces • Polished tile, linoleum, or wooden floors • Shiny desk or table tops, television screens & computer monitors realfengshuisolutions.wordpress.com Hardforum.com

  8. Sources of Glare • Reflective surfaces • Chrome fixtures, mirrors, and glossy tile in bathrooms • Uncovered light bulbs in lamps and ceiling fixtures creativeconceptsandcontracting.com etsy.com

  9. Sources of Glare • Reflective Wall Surfaces • lighting.co.uk

  10. Sources of Glare • Uncontrolled Sunlight • appliedproducts.co.uk hercampus.com

  11. A Closer Look at Uncontrollable Glare dreamstme.com

  12. Poll: Systematic glare assessments

  13. Three Types of Glare

  14. Poll: Glare Assessments

  15. Discomfort Glare It Starts Here lifechurchlancaster.org

  16. What is Discomfort Glare? • Quadrant Dependent • Occurs when visual field receives several different levels of light at the same time.

  17. Assessment of Discomfort Glare • Assess when student has an an intact temporal and/or superior peripheral visual field with a radius extending 10° or more from the macula. • Most prevalent during early morning or late afternoon when sun is low on the horizon.

  18. Assessment of Discomfort Glare • Select an environment causing discomfort glare • Ask student to subjectively note his or her visual comfort, while observing and documenting the severity of the client's squint reflex.

  19. Assessment of Discomfort Glare • Select an environment causing discomfort glare • Ask student to experience a situation of discomfort glare without and then with a visor • Ask student not to bring his hand up to his or her brow during this assessment. chesapeakebusiness.com

  20. Remediation of Discomfort Glare • Hat or visor with a brim that extends at least 3” forward from student’s forehead. • Grey underbrim = best color for light absorption (vs. reflection of light)

  21. Remediation of Discomfort Glare • Position visor on brow to block overhead light source, but not so low as to interfere with functional vision.  Bad Good 

  22. Remediation of Discomfort Glare • Bending sides of visor or hat downward (to curve the brim) helps minimize lateral discomfort glare from the temporal field of view

  23. Remediation of Discomfort Glare • As a note, sunglasses won’t help - they may reduce squinting due to bright light, but they also cut the light in shaded areas. • If student does wear sunglasses, tinted, yet translucent side shields are recommended. noir-medical.com

  24. Demonstrating Value of a Visor to the Student • Select an environment causing discomfort glare • Ask student to visually identify environmental features including traffic, pedestrians, traffic light color, and signs. • Document his squint reflex, subjective visual comfort, and the visual distance at which he can identify various environmental features. Document any unidentified features. • Ask the student to repeat the last two steps while wearing a hat or visor and discuss any differences in visual functioning with and without a hat or visor.

  25. Veiling Glare The “Dirty Windshield Effect” flickr.com

  26. What is Veiling Glare? • A • B • C Images credited to: R. Ludt, 1997

  27. Assessment of Veiling Glare • First, remediate any discomfort glare that may be present • Conduct assessment between 10 a.m. and 3 p.m. when short wavelength light is most intense. • First, position the student with the sun behind, and then in front. Observe any squints. Is there a difference? How severe is the squint?

  28. Remediation of Veiling Glare: Sunglasses • ANSI (American National Standard Institute) has 3 lens standards: • Cosmetic: "100% UV” can transmit 40% UVA, 30% UVB • General purpose: "100% UV” can transmit 40% UVA, 5% UVB • Special purpose: "100% UV” can transmit 1% UVA, 1% UVB

  29. A Few Notes About Sunglasses For All of Us • Wear “Special Purpose” UV filter lenses outside. • Wash glasses with water and blot with soft cotton cloth. Can rub off UV coating with dry tissue.

  30. A Special Word About Sunglasses… • Special Purpose Sunglasses • Color - red, orange, yellow, green, blue, indigo, violet • The tint color filters out the opposite end of the spectrum • Visible light transmission – 1% to 90% noir-medical.com

  31. Remediation of Veiling Glare • Surgical • Non-Surgical • Properly colored sunglasses • Mild squint  yellow • Moderate squint  orange • Severe squint  red • If student does wear sunglasses, tinted yet translucent side shields are recommended. noir-medical.com

  32. Dazzling Glare americanmigrainefoundation.org

  33. What is Dazzling Glare? • Abnormal sensitivity to intensity of ambient light (photophobia) • May have difficulty adapting to large changes in illumination and have a slow recovery from glare. • Two major causes include iris and retinal conditions • Some medications can cause photophobia

  34. Assessment of Dazzling Glare • First, remediate any discomfort and veiling glare that may be present • Assess glare sensitivity on both sunny and cloudy days.

  35. Assessment of Dazzling Glare • After student has had about 7 minutes to adjust to ambient light conditions, observe any squint to determine sensitivity level. eyedoctorguide.com

  36. Assessment of Dazzling Glare • Sensitivity levels • Mild = squint only • Moderate = squint, eye discomfort, decrease in visual resolution • Severe = student averts eyes from light source, experiences eye discomfort and a profound decrease in visual resolution.

  37. Remediation of Dazzling Glare

  38. Remediation of Dazzling Glare • Sensitivity Levels • Mild = 50-90% range of VLT • Moderate = 20-49% range of VLT • Severe = 0-19% range of VLT

  39. Remediation of Dazzling Glare • Verification of appropriate VLT should assess visual functioning in bright and cloudy conditions, and also include a light  shade evaluation. dunwoodyga.gov Ethnostravel.wordpress.com

  40. Summary

  41. Summary Assess in this order!

  42. Summary for Discomfort Glare (Shield eyes from source of glare) • Assess in early morning or late afternoon • Does student have intact temporal and superior fields? • Choose a hat or visor with at least a 3” brim and light underbrim color (not white).

  43. Summary for Discomfort Glare (Shield eyes from source of glare) • Select an environment causing discomfort glare • Ask student to visually identify environmental features • Document squint reflex, subjective visual comfort, and visual distance at which he can identify various environmental features. • Adjust visor as needed

  44. Summary for Veiling Glare (Choose properly colored sunglasses) • Assess between 10 AM  3 PM • Pick color of lenses that filters out short wavelengths that are most uncomfortable to student • Mild squint  yellow • Moderate squint  orange • Severe squint  light red

  45. Summary for Veiling Glare (Choose properly colored sunglasses) • Select an environment causing veiling glare • Ask student to visually identify environmental features • Document squint reflex, subjective visual comfort, and visual distance at which can identify various environmental features

  46. Summary for Dazzling Glare(Select optimum VLT) • Assess glare sensitivity on both sunny and cloudy days • Note squint (sensitivity) levels and choose proper range of VLT: Mild, moderate, or severe • Pick greatest amount of VLT student can tolerate without squinting or discomfort and that does not cause visual difficulty when moving from light  dark or dark  light

  47. NoIR Medical Technologies - noirmedical.com Colors of lenses Styles • Aviator • Clip-on • Fit over • Pediatric • Wrap Around NoIR Demo Kits: 12 tints/12 frames = $192.50 6 tints/6 frames = $110.00

  48. Unless otherwise noted, all pictures taken from pixabay.com References Colombo, L ., Melardi, E., Ferri, P., Montesano, G., Attaalla, S., Patelli, F., De Cilla, S., Savaresi, G., Rossetti, L. (2017). Visual function improvement using photocromic and selective blue-violet light filtering spectable lenses in patients affected by retinal diseases. BMC Ophthalmology, 17(149), pp. 1-6. Ludt, R. (1997). Three types of glare: Low vision O&M assessment and remediation. ReVIEW 29(3), 101-113 Renzi‐Hammond, L., Hammond, B. (2016). The effects of photochromic lenses on visual performance. Clinal and Experimental Optometry, 99(6). pp. 568-574. Wolska, A., Sawicki, D. (2014). Evaluation of discomfort glare in the 50+ elderly: experimental study. International Journal of Occupational Medicine and Environmental He 27(3). pp.444-459.

  49. Any Questions?

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