ILLUMINATION AND READIBILITY ISSUES IN ELDERS

Avinash Prabhune

Edu Mohan

Shashank Sawant

Avinash Jayakumar

What are we studying?

The human eye is a complex organ

Provides vital visual sensory feedback

Susceptible to different problems with age

Problems can be corrected, But How?

Lifestyle changes

Medical intervention

Environmental intervention

The Human Eye

Reference: (WebMD, 2009)

Problems with Age

Reference: (National Eye Institute USA, 2013).

Age-related Macular Degeneration (AMD)

Cataract Diabetic Eye Disease

Glaucoma Dry Eye Low Vision

Eye Disorders

BLIND

LOW VISION

VISUALLY IMPAIRED

Reference: WHO, (2008)

Illumination

Use of Light for aesthetic or practical application

Measurement of useful light falling on surface

SI Unit : Candela (Cd) luminous intensity

Luminosity function relative spectral sensitivity (to account for different light spectra)

Illuminance intensity of light hitting a surface, with respect to human eye (Unit: Lux)

Reference: (Paul Schlyter, Radiometry and photometry in Astronomy, 2006)

Illumination

Illuminance intensity of light hitting a surface (Unit: Lux), measured using a lux meter

As perceived by the eye:

0.0004 Lux = Moonless, overcast night

Reference: (Wikipedia.com, Lux, 2009)

0.5-1 Lux = Full moon, Clear night

50 Lux = Family living room lights

320-500 Lux = Office lighting

32,000-130,000 Lux = Direct Sunlight

Readability & Legibility

Readability - Ease with which text can read and understood

Legibility - measure of how easily individual letters or characters can be distinguished from each other

For this study, we combined both definitions and used a perceived Readability called Satisfaction Index

Reference: (Wikipedia.com, Readability, 2012)

The Actual Study

Subject interviews to understand the problem

Subjects across economic strata, different lifestyles / habits

Study improvement in satisfaction with illumination

Understand better: Quantify improvements using middle class

Reference: (Wikipedia.com, Readability, 2012)

The Experiment

3 subjects middle class retirees / housewives

2 different conditions at home (bedroom, hall)

Same newspaper given to all three subjects (Marathi Loksatta) and same medicine given

Illumination conditions

Ambient Light

With regular light (tube lights, etc)

With extra light (Focus Lamp)

The Subjects Subject 1 Subject 2 Subject 3

Place Mulund Mulund Mulund Subject Sunita Sawant Ramesh Tawde Pushpa Tawde

Age 72 69 68 Gender F M F

Health history

Eye related

Cataract operations of both eyes, occasional dryness, prescribed

glasses

Healthy eyes, reading glasses prescribed, diabetes

Cataract operation in one eye, glasses

prescribed

Other Spondylitis, chronic pain in the joints,

blood pressure Heart-related issues

Chronic pain in the joints, undergone knee replacement

surgery Job profile (history) House-wife Retired Manager (RBI) House-wife

Reading habits

what?

Newspapers, Periodicals, Books (religious, novels),

Medicines

Newspapers, Periodicals, Books (religious, novels), Documents,

Letters, Medicines

Newspapers, Periodicals, Books (religious, novels),

Medicines

when?&

how much?

Early morning, afternoon, evening,

night Reads all day, voracious reader

Early morning, afternoon, evening,

night

where?

Sofa, Balcony, beds Sofa, dining table Sofa, dining table,

bed

The Setting

The Data

Location: Living Room

Subjects LUX Meter reading (Lux)

Lights off Lights on Extra Light

1 247 573 883

2 173 270 612

3 264 300 650

Location: Bedroom

Subjects LUX Meter reading (Lux)

1 51 510 820

2 80 250 580

3 30 170 550

*The yellow highlight represents the favoured condition by the subject

The Results

*The yellow highlight represents the favoured condition by the subject

Preferences

Lights Switched off

Current condition

Additional Light

Conclusions

Regardless of conditions affecting the eyes previously additional illumination is preferred

Homes with the elderly should have access to better illumination regardless of social strata

A portable device offering about 300-350 Lux of additional light

Limitations

Time to gather data

Access to conduct experiments with different subjects from different economic status, especially low income group, more info is better

Identifying the link between postures and quality of eye sight

END