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

2. Poll: Who is with us today?
Which of these best describes your primary role with students who have visual impairments?

3. Lighting Considerations
Sufficient and diffuse is, of course, best
But, ideal is not always possible in reality!
LIGHTING IS CRITICAL TO THE OPTIMAL USE OF VISION

4. Lighting An often overlooked aspect of lighting is…Glare!!
elibishop.com
WE WILL LOOK ONE SPECIFIC ASPECT OF LIGHTING – GLARE
GLARE IS LIGHT THAT DOES NOT HELP ONE TO SEE BETTER, BUT THAT ACTUALLY CONTRIBUTE HAS AN ADVERSE EFFECT UPON VISUAL COMFORT OR CLARITY.

5. What is Glare?
Glare is "the dazzling sensation of relatively bright light, which produces unpleas­ antness or discomfort, or which interferes with optimum vision" (Cline. Hofstetter, & Griffin, 1989, p. 292).
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).
UNLESS GLARE SENSITIVITY IS CONTROLLED, AN EFFECTIVE LOW VISION O&M TRAINING PROGRAM CANNOT BEGIN.
THE TWO GOALS OF AN O&M GLARE RE-MEDIATION PROGRAM ARE TO MINIMIZE EYE DISCOMFORT AND TO MAXIMIZE VISUAL RESOLUTION.

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.
IF AN INDIVIDUAL IS SENSI­TIVE TO GLARE, THE PROBLEM EXISTS IN THE COMEAL LAYERS, LENS CAPSULE, LENS CORTEX, LENS NUCLEUS, VITREOUS, OR RETINA (FAYE, 1986; GAWANDE, ROLOFF, & MARMOR, 1992: JOSE, 1983: MAINO & MCMAHON, 1986).
THE O&M SPECIALIST SHOULD BE AWARE THAT SOME MEDICATIONS CAN HAVE SIDE EFFECTS THAT CAUSE ABNORMAL SENSITIVITY TO LIGHT. FOR EXAMPLE, SOME MEDICATIONS GIVEN TO PEOPLE WHO HAVE AIDS OR SOME TYPES OF CANCERS CAN CAUSE PHOTOPHOBIA. SIMILARLY, OCULAR STEROID TREATMENTS CAN RESULT IN EYE PAIN, REDNESS, AND PHOTOPHOBIA.
UNLESS GLARE SENSITIVITY IS CONTROLLED, A LOW VISION O&M TRAINING PROGRAM CANNOT PROCEED WITH FULL EFFECTIVENESS.
THE TWO GOALS OF AN O&M GLARE RE-MEDIATION PROGRAM ARE TO MINIMIZE EYE DISCOMFORT AND TO MAXIMIZE VISUAL RESOLUTION.

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
REFLECTIVE WALL SURFACES, INCLUDING GLOSSY PAINT, CAN ALSO BE SOURCES OF GLARE.
lighting.co.uk

10. Sources of Glare Uncontrolled Sunlight
UNCONTROLLED SUNLIGHT STREAMING IN THROUGH WINDOWS THAT HAVE NO CURTAINS OR SHADES CAN BE A MAJOR SOURCE OF GLARE.
appliedproducts.co.uk
hercampus.com

11. A Closer Look at Uncontrollable Glare
THERE ARE A NUMBER OF STRATEGIES TO REDUCE GLARE, INCLUDING:
CHANGING ONE’S BODY POSITION SO THAT ONE IS NOT FACING THE LIGHT DIRECTLY
USE A VISOR OR ABSORPTIVE LENSES SUCH AS NOIRS OR UVSHIELDS
MODIFYING THE ENVIRONMENT TO REDUCE GLARE.
dreamstme.com

12. Poll: Systematic glare assessments
Have you learned how to do a systematic glare assessment based on visual conditions either in school or as continuing education?

13. Related to Quadrant of light Related to Quality of light
Three Types of Glare
Related to Quadrant of light
Discomfort
Related to Quality of light
Veiling
Related to Quantity of light
Dazzling
THREE TYPES OF GLARE—DISCOMFORT GLARE, VEILING GLARE, AND DAZZLING GLARE—
WHEN ASSESSING A STUDENT FOR GLARE SENSITIVITY, IT IS CRITICAL TO ASSESS FOR GLARE IN THIS ORDER. THE PRESENCE OF DISCOMFORT GLARE CAN AFFECT THE ASSESSMENT RESULTS OF VEILING GLARE AND THE PRESENCE OF VEILING GLARE CAN AFFECT THE RESULTS OF ASSESSMENT FOR DAZZLING GLARE.

14. Poll: Glare Assessments
Please describe your experience conducting glare assessments with students

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.
AS AN EXAMPLE OF DISCOMFORT GLARE, A PERSON CAN BE FACING WEST ON A SUNNY AFTERNOON AND SCANNING TO FIND THE DOORWAY ON THE SHADY SIDE OF A BUILDING. THE PUPIL DILATES TO ALLOW IN MORE LIGHT FOR EXAMINING THE SHADED AREA OF THE BUILDING ENTRANCE. AT THE SAME TIME, HOWEVER, LIGHT RAYS FROM THE WESTERN SUN PEEKING OVER THE BUILDING’S ROOF CAN STILL BE PERCEIVED BY THE RETINA. REMEMBER, THE SUPERIOR VISUAL FIELD CAN EXTEND FROM APPROXIMATELY DEGREES FROM THE FOVEA (DEPENDING UPON A PERSON’S VISUAL FIELD).
THIS MEANS THAT AT THE SAME TIME THAT THE PUPIL DILATES TO ALLOW IN MORE LIGHT FOR EXAMINING THE SHADED AREA OF THE BUILDING, THE PUPIL ALSO NEEDS TO CONSTRICT TO REDUCE THE IMPACT OF DIRECT, OVERHEAD LIGHT HITTING THE RETINA IN THE SUPERIOR VISUAL FIELD. RAPID FLUCTUATIONS IN PUPIL SIZE CAN OCCUR AS THE EYE SCANS VARIED LEVELS OF BRIGHTNESS WITHIN THE FIELD OF VIEW, POSSIBLY RESULTING IN EYE FATIGUE, TEARING, HEADACHE, DISCOMFORT, AND POOR VISUAL RESOLUTION.

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.
THE O&M SPECIALIST SHOULD PLAN A DISCOMFORT GLARE ASSESSMENT WHEN THE RESULTS OF THE VISUAL FIELD EXAMINATION IDENTIFY THAT THE LOW VISION CLIENT HAS AN INTACT TEMPORAL AND/OR SUPERIOR PERIPHERAL VISUAL FIELD WITH A RADIUS EXTENDING 10° OR MORE FROM THE MACULA.
IN PEDESTRIAN SITUATIONS, DISCOMFORT GLARE CONDITIONS ARE MOST PREVALENT DURING EARLY MORNING OR LATE AFTERNOON WHEN THE 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.
STUDENTS WHO ARE UNACCUSTOMED TO WEARING A HAT OR VISOR MAY INITIALLY BE RELUCTANT TO DO SO FOR COSMETIC OR COMFORT REASONS. WHEN PROPERLY SHOWN HOW A VISOR CAN ENHANCE VIEWING COMFORT AND EFFICIENCY, THE STUDENT WILL THEN BE ABLE TO MAKE HIS OR HER DECISION WITH AN UNDERSTANDING OF THE BENEFITS THAT CAN BE REALIZED.

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.
THE STEPS LISTED IN THE NEXT FEW SLIDES CAN PRESENT A NON-THREATENING STRATEGY FOR PRESENTING A VISOR TO A STUDENT.
BEGIN THE LESSON BY ASKING THE CLIENT TO EXPERIENCE A SITUATION OF DISCOMFORT GLARE WITHOUT AND THEN WITH A VISOR—ANY HAT OR VISOR OF HIS CHOICE WITH A 3-IN. NONTRANSLUCENT BRIM.
THE O&M SPECIALIST SHOULD DOCUMENT SENSITIVITY TO DISCOMFORT GLARE EACH TIME THE CLIENT USES HIS OR HER HAND AS A VISOR TO REDUCE THE SQUINT REFLEX AND TO INCREASE VISUAL RESOLUTION.
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)
THE REMEDY IS A VISOR WITH A PROPER SIZE BRIM POSITIONED ON THE BROW TO BLOCK THE OVERHEAD LIGHT SOURCE FROM DIRECTLY ENTERING THE PUPIL (FAYE, 1986). VS USING HAND INTERMITTENTLY - WHICH LEAVES EYE IN PHOTOPIC STATE (ADJUSTED FOR BRIGHT LIGHTING) - THIS IS NOT OPTIMAL
THE BRIM OF THE VISOR SHOULD EXTEND FORWARD FROM THE CLIENT'S FOREHEAD A MINIMUM OF 3 INCHES TO ACHIEVE CONSISTENT CONTROL OF DISCOMFORT GLARE.
GREY UNDERBRIM IS 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 
TO BLOCK THE MAXIMUM AMOUNT OF DISCOMFORT GLARE, THE CLIENT SHOULD POSITION THE BRIM OF THE VISOR AS LOW ON THE BROW AS POSSIBLE WITHOUT INTERFERING WITH FUNCTIONAL VISION (ROSENBERG, 1984).

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
BENDING THE SIDES OF THE VISOR DOWN­WARD (TO CURVE THE BRIM) HELPS MINIMIZE LATERAL DISCOMFORT GLARE DIRECTED TOWARD THE EYE 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.
SUNGLASSES ARE NOT THE SOLUTION FOR DISCOMFORT GLARE - THEY WILL REDUCE THE SQUINTING DUE TO THE BRIGHT LIGHT, BUT THEY ALSO CUT THE LIGHT IN THE SHADED AREA. IF DISCOMFORT GLARE IS IDENTIFIED AS THE ONLY PROBLEM, SUNGLASSES ARE OF DOUBTFUL VALUE (SLINEY, 1983). TINTED GLASSES WILL REDUCE THE AMBIENT BRIGHTNESS BUT MAKE THE DARK AREAS DARKER AND MAY RENDER INVISIBLE DETAILS OF SHADED AREAS (PITTS, 1990).
ALTHOUGH TRANSLUCENT SIDE SHIELDS ATTACHED TO THE TEMPLE OF SPECTACLE GLASSES MAY ALSO REDUCE LATERAL DISCOMFORT GLARE FROM THE TEMPORAL SIDE OF THE VISUAL FIELD, OPAQUE SIDE SHIELDS WILL REDUCE THE TRANSMISSION OF NECESSARY LIGHT AS WELL AS THE VISUAL FIELD OF VIEW (ROSENBERG, 1984). TINTED, YET TRANSLUCENT, SIDE SHIELDS ARE RECOMMENDED AND ARE AVAILABLE THROUGH OPTICAL SUPPLY COMPANIES.
noir-medical.com
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.
1. SELECT AN ENVIRONMENT CAUSING DISCOMFORT GLARE WITH AS MANY RELEVANT PEDESTRIAN ELEMENTS (E.G., A CHANGE IN TRAVEL SURFACE TEXTURE, THE PRESENCE OF A SMALL OBSTACLE IN THE CLIENT'S LINE OF TRAVEL, A CURB OR SHORT FLIGHT OF STEPS, A STAIR HANDRAIL, A CONTOUR CHANGE, A BUILDING ENTRANCE DOOR, DOOR HARDWARE, PLANTERS HANGING AT HEAD LEVEL, A BENCH, SIGNS, LANDMARKS, AND ADDRESS NUMBERS) IN THE SHADE AS POSSIBLE
2. DOCUMENT HIS SQUINT REFLEX, SUBJECTIVE VISUAL COMFORT, AND THE VISUAL DISTANCE AT WHICH HE CAN IDENTIFY THE PEDESTRIAN ELEMENTS. DOCUMENT ANY UNIDENTIFIED ELEMENTS.
ASK THE CLIENT TO SUBJECTIVELY NOTE HIS VISUAL COMFORT, WHILE OBSERVING AND DOCU­MENTING THE SEVERITY OF THE CLIENT'S SQUINT REFLEX.
3. ASK THE CLIENT NOT TO BRING HIS HAND UP TO HIS BROW DURING THIS ASSESSMENT. IF THE CLIENT EXPERIENCES INTOLERABLE DISCOMFORT, THEN HE SHOULD TURN AWAY FROM THE LIGHT SOURCE. HAVING GIVEN ALL THE INSTRUCTIONS, ASK THE CLIENT TO FACE THE SITUATION OF DISCOM­FORT GLARE WITHOUT WEARING A VISOR.
4. ASK THE CLIENT TO REPEAT THESE STEPS WHILE WEARING A VISOR.
5. DISCUSS THE RESULTS OF THE ASSESSMENT WITH THE CLIENT.

25. The “Dirty Windshield Effect”
Veiling Glare
The “Dirty Windshield Effect”
MANY STUDENTS COMPARE THE SENSATION TO TRYING TO LOOK THROUGH A DIRTY CAR WINDSHIELD. THEY MAY SQUINT IN AN EFFORT TO MINIMIZE THE LIGHT COMING INTO THE EYE AND THEREBY REDUCE THE SCATTER EFFECT.
flickr.com
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OMIT:
albinism "stray light that interferes with visual resolution because it is random and thereby reduces the contrast of the figure/ground in the retinal image" (Rosenberg, 1984, p. 197). The scattering of light caused by ocular media opacities from such eye conditions as cataracts, comeal dystrophy, a translu­cent iris (iritis, albinism), vitreous opacities, and diffusion through the sclera produce this kind of glare (Beckman, Hard, Hard, & Sjostrand, 1992; CTConner, 1988).
flickr.com

26. What is Veiling Glare? A B C Images credited to: R. Ludt, 1997
VEILING GLARE (ALSO CALLED DISABILITY GLARE) MAY BE SEEN WHEN A STUDENT HAS OCULAR OPACITIES FROM SUCH CONDITIONS AS CATARACTS, CORNEAL DYSTROPHY, VARIOUS VITREOUS OPACITIES, OR WHERE HE OR SHE HAS A TRANSLUCENT IRIS AS IN IRITIS OR ALBINISM.
SINCE VEILING GLARE IS WAVELENGTH DEPENDENT, THE GLARE IS CAUSED WHEN SHORT WAVELENGTH LIGHT RAYS ((BLUE AND VIOLET: NANOMETERS) HIT THE OPACITY. WHEN THIS HAPPENS, THE STRAY LIGHT INTERFERES WITH VISUAL CLARITY AND REDUCES THE CONTRAST OF THE FIGURE/GROUND IN THE RETINAL IMAGE.
THIS SCREEN SHOWS THAT WHILE SOME LONG WAVELENGTH LIGHT RAY MAY MISS THE OPACITY AND REACH THE RETINA INTACT, IT IS MORE LIKELY FOR SHORT WAVELENGTH RAYS TO CONTACT THE OPACITY AND SCATTER. THIS IS KNOWN AS "RAYLEIGH SCATTER”.
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?
THE O&M SPECIALIST SHOULD MAKE CERTAIN THAT ANY SENSITIVITY TO DISCOMFORT GLARE HAS BEEN RESOLVED BEFORE BEGINNING THE ASSESSMENT OF VEILING GLARE.
BECAUSE VEILING GLARE DEPENDS ON SHORT VISIBLE WAVELENGTH, THE O&M ASSESSMENT SHOULD BE CONDUCTED BETWEEN 10 A.M. AND 3 P.M. WHEN SHORT WAVELENGTH LIGHT IS MOST INTENSE.
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NOT USED:
After reading the eye report, the O&M specialist can confirm the client's degree of sensitivity to veiling glare by observing a squint reflex in the presence of short wave­length light. The O&M specialist's functional classification of the client's squint reflex as mild, moderate, or severe determines the proper veiling glare remedy. The assessment route should begin with the sun at the client's back. The O&M specialist must careful­ly observe and document the client's squint reflex on each leg of the route.
The O&M specialist should read the report of the client's eye examination and then customize the O&M assessment, based on the severity, type, and location of the ocular media opacity* For example, the clinical report of **2+ posterior sub capsular cataracts, OU," characterizes the severity of the opacity with the use of a a numerical system, before mention is made that the cataract is one in which the opacities are concentrated beneath the capsule. The method that eye-care professionals use to rate the severity of an ocular media opacity is
1+ = immature (mildly advanced)
2-»- to 3+ = mature (moderately advanced)
4+ == hypermature (far advanced)

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
WHILE SUNGLASSES CAN BE PURCHASED AT DRUG STORES, CHAIN STORES, AND OTHER OUTLETS, THERE ARE ASPECTS TO CHOOSING THE CORRECT SUNGLASSES TO DEAL WITH SOME FORMS OF GLARE.
ANSI (AMERICAN NATIONAL STANDARD INSTITUTE) HAS 3 STANDARDS:
COSMETIC LENSES: "100% UV" COSMETIC LENS CAN TRANSMIT 40% UVA, 30% UVB; CAN BE WORSE THAN WEARING NO SUNGIASSES AS THE TINT CAN CAUSE THE PUPIL TO DILATE AND LET MORE UV IN (THAN IF WEARING NO SUNGLASSES WITH PUPILS CONSTRICTED)
GENERAL PURPOSE: "100% UV" GENERAL PURPOSE LENS CAN TRANSMIT 40% UVA, 5% UVB
SPECIAL PURPOSE: "100% UV" SPECIAL PURPOSE LENS 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.
WE ALL SHOULD WEAR “SPECIAL PURPOSE” UV FILTER LENSES OUTSIDE. UV LIGHT IS INVISIBLE. IT CAN DAMAGE THE EYE, CAUSING CATARACTS AND MACULAR DEGENERATION. MAY ALSO CAUSE DEGENERATIVE RETINAL CONDITIONS (IE RP) TO DETERIORATE MORE QUICKLY.

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%
WHEN WE TALK ABOUT SUNGLASSES IN THIS MODULE, WE WILL BE SPECIFICALLY REFERRING TO SPECIAL PURPOSE SUNGLASSES SUCH AS NoIRS AND UV SHEILDS – THOSE THAT HAVE BEEN SCIENTIFICALLY VERIFIED TO ADDRESS THE VISUAL CONCERNS WE WILL BE DISCUSSING. THESE SPECIAL SUNGLASSES ARE DESIGNED TO FILTER OUT VARIOUS WAVELENGTHS OF LIGHT FOR SPECIFIC PURPOSES.
BEFORE WE START, NEED TO TALK ABOUT:
THE TWO MAJOR ASPECTS OF CHOOSING THE CORRECT LENSES ARE “COLOR TINT” AND ”VISIBLE LIGHT TRANSMISSION”.
COLOR SPECTRUM = ROYGBIV (RED, ORANGE, YELLOW, GREEN, BLUE, INDIGO, VIOLET) THE TINT COLOR FILTERS OUT THE OPPOSITE END OF THE SPECTRUM. I.E. RED/ORANGE/YELLOW FILTERS OUT THE BLUE/INDIGO/VIOLET
SOME TINTS AFFECT COLOR PERCEPTION, SOME DO NOT; SOME AFFECT CONTRAST, OTHERS DO NOT. THE CORRECT TINT AND COLOR WILL HAVE MUCH TO DO WITH A PERSON’S VISUAL CONDITION. FINDING THE RIGHT TINT IS SOMETIMES A TRADEOFF OF COLOR, CONTRAST, AND GLARE CONTROL.
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.
SURGICAL REMEDY FOR VEILING GLARE
IN SOME SITUATIONS, SUCH AS WHEN THE OPACITY IS DUE TO CATARACTS, THE CATARACT CAN BE REMOVED, THE LENS REPLACED, AND THE GLARE SENSITIVITY REMEDIATED.
WHEN SURGERY IS NOT POSSIBLE, OR IF IT DOES NOT COMPLETELY REDUCE GLARE SENSITIVITY, THERE ARE SEVERAL NON-SURGICAL APPROACHES TO ADDRESSING THE SITUATION.
NONSURGICAL REMEDIES FOR VEILING GLARE
FIRST, A HAT OR VISOR CAN BLOCK THE INTENSE, SHORT VISIBLE WAVELENGTH LIGHT ENTERING THE EYE FROM OVERHEAD. SHORT WAVELENGTH LIGHT, HOWEVER, CAN ALSO REFLECT OFF ENVIRONMENTAL SURFACES SUCH AS SNOW, WATER, SAND, AND SIDEWALKS.
SELECTING THE PROPER CHROMATIC (COLOR) LENSES IS THE KEYS TO REMEDYING VEILING GLARE.
THE REMEDY FOR SENSITIVITY TO VEILING GLARE IS SUNGLASSES WITH A LIGHT (50-90%, VLT) TINT OF YELLOW, ORANGE, OR RED. THESE COLORS ABSORB ABSORBS THE SHORT TO MEDIUM END OF THE VISIBLE SPECTRUM (BLUE AND VIOLET END OF THE SPECTRUM). ONLY THE LONGER WAVELENGTHS, NOT SCATTERED BY THE SMALL OPACITIES, REACH THE RETINA, THUS MINIMIZING RAYLEIGH SCATTER (ZIGMAN, 1992).
I USUALLY START WITH A LIGHT TINT FIRST % LIGHT TRANSMISSION.
BECAUSE THE PROPER COLOR TINT IS THE REMEDY FOR VEILING GLARE/PEOPLE WITH LOW VISION SHOULD CHOOSE A HIGH VLT LENS TO ENHANCE FIGURE-GROUND CONTRAST
FOR MILD VEILING GLARE, A LIGHT YELLOW TINT THAT FILTERS UP TO APPROXIMATELY 475 NM IS RECOMMENDED;
FOR MODERATE VEILING GLARE, A LIGHT ORANGE TINT THAT FILTERS UP TO 525 NM;
FOR SEVERE GLARE, A LIGHT RED TINT THAT FILTERS UP TO 575 NM.
A FEW IMPORTANT NOTES ABOUT COLOR:
YELLOW AND ORANGE LENSES WILL FILTER VIOLET AND BLUE (BUT NOT AS EFFECTIVELY AS RED LENSES), BUT CAN WORK FOR A PERSON WITH A SMALLER OPACITY.
RED LENSES WILL COMPLETELY FILTER NM/VIOLET AND BLUE - MAY MAKE IT DIFFICULT TO SEE GREEN TRAFFIC LIGHT.
AMBER/YELLOW TINTS GIVE THE PERCEPTION OF ENHANCED CONTRAST. THIS CAN BE VERY USEFUL TO PEOPLE WHO HAVE DECREASED CONTRAST SENSITIVITY.
GRAY AND GREEN TINTS GENERALLY DO NOT AFFECT COLOR PERCEPTION. THEY ARE USEFUL FOR PEOPLE WHO HAVE GOOD NATURAL COLOR PERCEPTION AND FOR WHOM COLOR IS IMPORTANT.
AS A NOTE, HOWEVER, DIFFERENT COLOR TINTS CAN GIVE AN IMPRESSION OF MORE OR LESS DARKNESS, EVEN IF THEY ARE ACTUALLY GIVING THE SAME TRANSMISSION.
FOR EXAMPLE, A GREEN SEEMS PERCEPTUALLY DARKER THAN A GRAY TINT OF THE SAME LIGHT TRANSMISSION. IF THINGS SEEM TOO BRIGHT WHEN LOOKING THROUGH A 40% YELLOW LENS, TRY A 40% AMBER OR GREEN LENS.
IF STILL SQUINTING, THE PERSON IS EXPERIENCING DAZZLING GLARE. SEE NEXT SLIDES FOR DAZZLING GLARE.
noir-medical.com

32. Dazzling Glare
DAZZLING GLARE OCCURS WHEN AN INDIVIDUAL HAS AN ABNORMAL VISUAL SENSITIVITY TO THE INTENSITY OF AMBIENT LIGHT (PHOTOPHOBIA). LIGHTING IS PRESENT THAT IS ABOVE SENSITIVITY LEVELS THAT EYE CAN HANDLE LIGHTING OVERWHELMS RETINAL FIELD
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
TWO MAJOR CAUSES OF DAZZLING GLARE ARE DYSFUNCTION OF THE IRIS AND RETINAL DISEASE.
THE O&M SPECIALIST SHOULD BE AWARE THAT SOME MEDICATIONS CAN HAVE SIDE EFFECTS THAT CAUSE ABNORMAL SENSITIVITY TO LIGHT. FOR EXAMPLE, SOME MEDICATIONS GIVEN TO PEOPLE WHO HAVE AIDS OR SOME TYPES OF CANCERS CAN CAUSE PHOTOPHOBIA. SIMILARLY, OCULAR STEROID TREATMENTS CAN RESULT IN EYE PAIN, REDNESS, AND PHOTOPHOBIA.
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OMIT:
Light and Retinal Cross-Linking
The O&M specialist needs to understand how light is processed from the retina to the optic nerve and why individuals with retinal eye disorders are often sensitive to dazzling glare. When light stimulates the retina's rod and cone photoreceptors. a complex chain of photochemical reactions begins. Of the five classes of retinal neurons, only the rod and cone photoreceptors, the bipolar cells, and the ganglion cells form a direct pathway from the retina to the brain (Long, 1992). The remaining two classes of reti­nal neurons, the horizontal cells and the amacrine cells, form lateral pathways that modify and control retinal information (Masland, 1986).
Before any neural information is sent to the optic nerve, those cross-linking connec­tions spread over the entire retina and are able to modify the neural transmission inten­sity of light to the brain. Any damage to these connections adversely affects the eye's ability to modify the light intensity, resulting in photophobia (Hecht, 1987).
(scotopic = eye in dark state; photopic = eye in light state

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.
BEFORE BEGINNING AN ASSESSMENT OF DAZZLING GLARE, THE O&M SPECIALIST SHOULD MAKE SURE THAT ANY SENSITIVITY THE CLIENT MAY HAVE TO DISCOMFORT, VEILING GLARE, OR BOTH HAS BEEN RESOLVED.
ATTEMPTING TO ASSESS DAZZLING GLARE FIRST OFTEN RESULTS IN SELECTING THE WRONG GLARE CONTROL REMEDY AND UNNECESSARILY REDUCING THE CLIENT'S VISUAL EFFICIENCY.
THE SPECIALIST SHOULD THEN PLAN ASSESSMENT ROUTES FOR BOTH OVERCAST AND CLEAR SUNNY 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.
A PHOTOPHOBIC PERSON MAY HAVE UNUSUAL DIFFICULTY ADAPTING TO DRAMATIC CHANGES IN ILLUMINATION AND A SLOW RECOVERY FROM GLARE (JOSE, 1983).
THE NORMAL EYE CAN TAKE UP TO 1 HOUR TO REACH OPTIMAL FUNCTIONING IN CHANGES OF LIGHTING FROM BRIGHT TO DIM, AND 5-7 MINUTES FOR DARK TO BRIGHT)
OBSERVING THAT THE CLIENT SQUINTS AFTER A SUDDEN TRANSITION FROM A DIM TO A BRIGHT LIGHTING ENVIRONMENT SHOULD NOT BE DOCUMENTED AS SENSITIVITY TO DAZZLING GLARE. TO ACHIEVE ACCURATE RESULTS WHEN ASSESSING DAZZLING GLARE, MAKE SURE THE CLIENT HAS APPROXIMATELY 7 MINUTES TO ADAPT TO THE AMBIENT LIGHTING CONDITIONS (GREGORY, 1990)
IF THE EYE REPORT INDICATES THAT THE CLIENT HAS A RETINAL EYE DISORDER, THE O&M SPECIALIST CAN EXPECT THAT THE CLIENT WILL BE SENSITIVE TO DAZZLING GLARE.
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OMIT
Although the human pupil can constrict or dilate in l/5th of a second, the retinal cone and rod photoreceptor cells require more time to adapt. The cone cells need at least 7 minutes adapt, and the rod cells require nearly 1 hour to fully adapt to dark. The O&M specialist needs to understand that even if the rod and cone cells could adapt more quickly, the problem of discomfort glare would not be solved because the retina adjusts only to ambient light across the entire visual field (Miller, 1974).
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.
HAVING GIVEN THE CLIENT TIME TO ADAPT TO THE LIGHT, THE SPECIALIST SHOULD DOCUMENT THE THREE CLASSIFICATIONS OF A CLIENT'S SENSITIVITY TO DAZZLING GLARE AS FOLLOWS:
(A) SQUINT REFLEX ONLY = MILD:
(B) SQUINT REFLEX, COMPLAINT OF EYE DISCOMFORT, AND A DECREASE IN VISUAL RESOLUTION = MODERATE;
(C) EYES AVERTED FROM THE LIGHT SOURCE, A COMPLAINT OF EYE DIS­COMFORT, AND PROFOUND DECREASE IN VISUAL RESOLUTION = SEVERE.

37. Remediation of Dazzling Glare
A STUDENT WITH OPACITIES IN THE OCULAR MEDIA, AS WELL AS A RETINAL DISEASE, MAY ALREADY HAVE THE CORRECT TINT COLOR REMEDY FOR VEILING GLARE BUT CONTINUE TO SQUINT BECAUSE OF DAZZLING GLARE.
PEOPLE WITH LOW VISION WHO ARE NOT SENSITIVE TO VEILING GLARE MAY PREFER A PAIR OF GRAY TINT SPECTACLES
GRAY IS REFERRED TO AS A NEUTRAL DENSITY COLOR BECAUSE IT FILTERS EVENLY ALL THE VISIBLE WAVELENGTHS OF LIGHT AND THEY DON'T AFFECT COLOR PERCEPTION
GREEN TINTS WILL BE PERCEIVED AS LESS LIGHT EVEN IF THEY HAVE THE SAME PERCENTAGE OF LIGHT TRANSMISSION AS GREY TINTS.
THE APPROPRIATE REMEDY FOR THIS DAZZLING GLARE IS TO LOWER THE PERCENTAGE OF LIGHT TRANSMITTED THROUGH THE TINT COLOR CHOSEN TO REMEDY VEILING GLARE.
THE AIM IS TO SELECT LENSES WITH THE MAXIMUM LEVEL OF VLT POSSIBLE WHILE STILL REMEDIATING THE GLARE SENSITIVITY
SUNGLASSES WITH HIGH LIGHT TRANSMISSION ALSO HELP THE EYE MAINTAIN AS EVEN AN ADAPTATION STATE AS POSSIBLE, AND IT IS HOPED THE GLASSES ALSO WILL MINIMIZE THE DIFFICULTIES STUDENTS EXPERIENCE WHEN MOVING FROM ONE LIGHTING CONDITION TO ANOTHER.
ALSO, EXCESSIVE REDUCTION OF LIGHT TO THE EYE DECREASES VISUAL ACUITY
PHILLIPS AND RUTSTEIN (1965) DEMONSTRATED THAT EVERY PERCENTAGE DECREASE IN LIGHT TRANSMISSION TO THE EYE RESULTS IN A CORRESPONDING PERCENTAGE DECREASE IN VISUAL ACUITY.

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
A STUDENT WHO HAS:
MILD SENSITIVITY TO DAZZLING GLARE SHOULD USE A 90-50% RANGE OFTLT (HIGH) TO ACHIEVE THE BEST COMFORT WHILE MAINTAINING THE INTEGRITY OF VISUAL RESOLUTION (GOODLAW, 1991).
FOR MODERATE SENSITIVITY TO DAZZLING GLARE, 49-20% TLT (MODERATE) WOULD BE APPROPRIATE TO EVALUATE.
SEVERE SENSITIVITY REQUIRES 19-1% TLT (LOW).

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.
ONCE YOU DETERMINE THE STUDENT'S MAXIMUM TOLERANCE FOR LIGHT TRANSMISSION IN BRIGHT CONDITIONS, BEGIN A LIGHT-TO-SHADE
THE OBJECTIVE OF THAT EVALUATION IS TO DETERMINE WHAT PERCENTAGE OF VLT ALLOWS THE CLIENT TO CONTINUE TO MAINTAIN OPTIMUM VISIBILITY IN VARIED ILLUMINATIONS.
A TRIAL PERIOD OF SEVERAL DAYS IS RECOMMENDED TO COMPARE EACH INDIVIDUAL PAIR OF SUNGLASSES (MORRIS-SETTE, MEHR, KESWICK, & LEE, 1984).
GO TO SUMMARY>
++++
AN INCREASE IN TLT WOULD BE JUSTIFIED IF THE CLIENT CONTINUES VISUALLY TO IDENTIFY RELEVANT PEDESTRIAN ELEMENTS, AT INCREASING DISTANCES, WHILE MAINTAINING VIEWING COMFORT IN BRIGHT AMBIENT ILLUMINATION.
NOT USED:
Eye care professionals who have a low vision client with photophobia caused by trauma or dysfunction of the iris may prescribe an opaque contact lens that has an artificial pupil (Nowakowski, 1992).
Other remedies for dazzling glare exist for clients who decline an opaque contact lens or whose photophobia results from a reti­nal eye disease.
Only the three types of dazzling glare discussed in this article are resolved by lowering the entire visible light spectrum with chromatic tint sunglasses (CTS).
Once the proper ultraviolet protection of the lenses has been confirmed, no damage to the eye occurs if, during a pedestrian evaluation of color tint sunglass, the client uses a tint that transmits light so intense that it causes momentary discomfort (C. W. Keswick, O.D., personal communication, 1994).
Final Evaluation of Sunglasses
Give greatest amount of light that student can tolerate. For every percentage of decreased light transmission, the acuity drops the same percentage.
Because the goal in remedying dazzling glare is to find the maximum light transmis­sion through the lens that the client can tolerate, the O&M specialist needs to consider the following when helping the client make the final selection of sunglasses:
1. For viewing comfort, the lens should reduce squinting and tearing.
2. The lens that meets the assessment criteria for maximizing visual resolution should have adequate TLT to allow the client to travel through moderate changes in luminance without needing constantly to put on and take off the sunglasses.
3. The client should compare the differences between the suggested sunglasses and those currently in use and should check the results of the initial assessment against cur­rent distance thresholds.
4. The effect that the chromatic tint has on the client's color-brightness perception and his or her opinion of the cosmetic appearance, the ease of use, and the performance of the sunglasses are all crucial factors.
dunwoodyga.gov
Ethnostravel.wordpress.com

40. Summary
DAZZLING GLARE OCCURS WHEN AN INDIVIDUAL HAS AN ABNORMAL VISUAL SENSITIVITY TO THE INTENSITY OF AMBIENT LIGHT (PHOTOPHOBIA). LIGHTING IS PRESENT THAT IS ABOVE SENSITIVITY LEVELS THAT EYE CAN HANDLE LIGHTING OVERWHELMS RETINAL FIELD

41. Related to Quadrant of light Related to Quality of light
Summary
Related to Quadrant of light
Discomfort
Related to Quality of light
Veiling
Related to Quantity of light
Dazzling
THREE TYPES OF GLARE—DISCOMFORT GLARE, VEILING GLARE, AND DAZZLING GLARE—
WHEN ASSESSING A STUDENT FOR GLARE SENSITIVITY, IT IS CRITICAL TO ASSESS FOR GLARE IN THIS ORDER. THE PRESENCE OF DISCOMFORT GLARE CAN AFFECT THE ASSESSMENT RESULTS OF VEILING GLARE AND THE PRESENCE OF VEILING GLARE CAN AFFECT THE RESULTS OF ASSESSMENT FOR DAZZLING GLARE.
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
REMEMBER, A HAT OR VISOR CAN BLOCK THE INTENSE, SHORT VISIBLE WAVELENGTH LIGHT ENTERING THE EYE FROM OVERHEAD. SHORT WAVELENGTH LIGHT, HOWEVER, CAN ALSO REFLECT OFF ENVIRONMENTAL SURFACES SUCH AS SNOW, WATER, SAND, AND SIDEWALKS.
SELECTING THE PROPER CHROMATIC (COLOR) LENS ARE THE KEYS TO REMEDYING VEILING GLARE.
THE REMEDY FOR SENSITIVITY TO VEILING GLARE IS SUNGLASSES WITH A LIGHT (50-90%, VLT) TINT OF YELLOW, ORANGE, OR RED.
THESE COLORS ABSORB ABSORBS THE SHORT TO MEDIUM END OF THE VISIBLE SPECTRUM (BLUE AND VIOLET END OF THE SPECTRUM).
ONLY THE LONGER WAVELENGTHS, NOT SCATTERED BY THE SMALL OPACITIES, REACH THE RETINA, THUS MINIMIZING RAYLEIGH SCATTER (ZIGMAN, 1992).
BECAUSE THE PROPER COLOR TINT IS THE REMEDY FOR VEILING GLARE/PEOPLE WITH LOW VISION SHOULD CHOOSE A HIGH VLT LENS TO ENHANCE FIGURE-GROUND CONTRAST
FOR MILD VEILING GLARE, A LIGHT YELLOW TINT THAT FILTERS UP TO APPROXIMATELY 475 NM IS RECOMMENDED;
FOR MODERATE VEILING GLARE, A LIGHT ORANGE TINT THAT FILTERS UP TO 525 NM;
FOR SEVERE GLARE, A LIGHT RED TINT THAT FILTERS UP TO 575 NM.
IF STILL SQUINTING, THE PERSON IS EXPERIENCING DAZZLING GLARE. SEE NEXT SLIDES.

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
REMEMBER, A HAT OR VISOR CAN BLOCK THE INTENSE, SHORT VISIBLE WAVELENGTH LIGHT ENTERING THE EYE FROM OVERHEAD. SHORT WAVELENGTH LIGHT, HOWEVER, CAN ALSO REFLECT OFF ENVIRONMENTAL SURFACES SUCH AS SNOW, WATER, SAND, AND SIDEWALKS.
SELECTING THE PROPER CHROMATIC (COLOR) LENS ARE THE KEYS TO REMEDYING VEILING GLARE.
THE REMEDY FOR SENSITIVITY TO VEILING GLARE IS SUNGLASSES WITH A LIGHT (50-90%, VLT) TINT OF YELLOW, ORANGE, OR RED.
THESE COLORS ABSORB ABSORBS THE SHORT TO MEDIUM END OF THE VISIBLE SPECTRUM (BLUE AND VIOLET END OF THE SPECTRUM).
ONLY THE LONGER WAVELENGTHS, NOT SCATTERED BY THE SMALL OPACITIES, REACH THE RETINA, THUS MINIMIZING RAYLEIGH SCATTER (ZIGMAN, 1992).
BECAUSE THE PROPER COLOR TINT IS THE REMEDY FOR VEILING GLARE/PEOPLE WITH LOW VISION SHOULD CHOOSE A HIGH VLT LENS TO ENHANCE FIGURE-GROUND CONTRAST
FOR MILD VEILING GLARE, A LIGHT YELLOW TINT THAT FILTERS UP TO APPROXIMATELY 475 NM IS RECOMMENDED;
FOR MODERATE VEILING GLARE, A LIGHT ORANGE TINT THAT FILTERS UP TO 525 NM;
FOR SEVERE GLARE, A LIGHT RED TINT THAT FILTERS UP TO 575 NM.
IF STILL SQUINTING, THE PERSON IS EXPERIENCING DAZZLING GLARE. SEE NEXT SLIDES.

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
THEIR WEBSITE EVEN HAS A GUIDE WITH RECOMMENDED COLORS FOR VARIOUS EYE CONDITIONS.
CAN PURCHASE DEMONSTRATION KITS:
12 tints/12 frames = $192.50
6 tints/6 frames = $110.00
Example of 6 piece kit:
450#38, Light Yellow tint in large fitover frame
402#35, Medium Grey/Green tint in wrap-a-round non-fitover frame
901, UVShield, Medium Amber in large fitover style
411#53, Light Amber in large modern fitover frame
423#31, Dark Grey in small fitover frame
U41, UV Shield, Rose tint in universal fitover style
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),
Renzi‐Hammond, L., Hammond, B. (2016). The effects of photochromic lenses on visual performance. Clinal and Experimental Optometry, 99(6). pp
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
Unless otherwise noted, all pictures taken from pixabay.com
greenopolis.com
Images included are under fair use exemption of the U.S. Copyright Law, have been prepared with the multimedia fair use guidelines, and are restricted from further use.

49. Any Questions?