Does Reading in Low
Light Cause Eye
Damage?
Jamie Baker, Saiida Bowie-Little,
Shakira Collier, Logan Goff, Te’Asia
Lyles, Heather Neifert, Devina Patel,
Matthew Zyle, Shannon Cahalan
Healthcare Belief
A person who reads in low or dimly lit environments will
have permanent eye damage from this act.
Initial Group Vote
Fact:
5
Fiction:
4
Background
Light entering the eye is sensed in the retina
•Rods – low light vision
•Cones – color and detail
Detection of light sets off a chain of electric impulses,
ultimately transmitting interpreted light and image to brain via
optic nerve
•Iris – colored eye muscle; controls the opening and closing of
the pupil (dilation)
Background
Reading in a dark room sends iris two different signals:
• Darkness--relax to allow more light into the pupil
• Reading--contract to maintain focus on words being read
Darkness causes less clear contrast between words and page,
leading to decreased visual acuity, so eye muscles must work
harder, causing strain and irritation
Eye strain: tiring of eyes after intense use
• Usually a short-term annoyance; eye muscles recover,
permanent damage unlikely
• Blinking and breaking focus helps
• Caused by prolonged computer use, extended driving
periods
Background
Some professionals believe constant strain on the eyes may lead to
nearsightedness (myopia).
The constant strain required for the eye to distinguish between
foreground and background on the page could possibly cause long
term damage to the muscles and future problems
However, many argue that symptoms of nearsightedness in patients
who read in the dark is a coincidental overlap.
Some claim that strains from reading in the dark merely tire eye
muscles, similar to other muscular exercises.
Background
Dr. Katrina Schmid’s Study in Brisbane
• Demonstration for Ninemsn article using autorefractor
• Looked at how a person’s eyes focus on a page in dim and bright
light, then measured time needed to focus on something in the
distance after looking up
Findings:
• Changing focus between near and far objects more difficult,
much less accurate in dim vs. bright light
• Since cones don't work as well in dim light, decreased detail
perception of closer objects and greater difficulty focusing on
them accurately and correctly
Hypothesis
If a person reads in the dark, their eyesight will not be
ruined permanently, only strained at that moment.
Experiment
Studies show that reading in low light does not damage eyes, but
rather causes eye strain.
“Dim light might make it difficult for the eyes to focus, which can
cause short-term eye fatigue...but there is no scientific evidence
that reading in the dark does any long-term harm to your eyes”.
-Dr. Richard Gans, MD
The Cleveland Clinic Health Library states that “as with sitting too
close to the television or a computer screen may give you a
headache, you may get a headache from reading in the dark, but it
will not weaken your sight”.
Experiment
Experiment Procedure:
1.) Stand 9 feet away from a Snellen Eye Chart.
2.) Test each participant’s eyes separately and record the last line of
the eye chart that the participant read correctly.
3.) Sit in a dark room for around 3 minutes to adjust eyes to
environment.
4.) Read a book at the high school reading level for three minutes in
this dimly lit room.
5.) Return to Snellen Eye chart, stand 9 feet away and test both
eyes separately to see the difference from before reading in the dark
room.
Experiment
There were eleven lines on
the Snellen Eye Chart and
there were eight test subjects.
The number recorded was
the last line read correctly by
the subject for each eye.
Data Analysis
Data Analysis
Data Analysis
The results of our experiment:
• Four of the participants had weakened eyesight after reading in
dim light
• Three of the participants had improved eyesight
• One participant’s eyesight stayed the same
The data were inconclusive because of the lack of trend in results.
This was not a reliable study due to variability in time for eye
adjustment to darkness, degree of darkness, time adjusted to light
after reading and random human error. Also, this study does not
address long term damage.
Conclusion
• Reading in low light does not cause long term eye
damage. Though it does strain the eyes, they
recover in a short period of time and permanent
damage is unlikely.
• Although the results from our own experiment were
inconclusive, other more credible experiments
have been conducted to prove our hypothesis.
Communication of Results
References
"Does Reading in Dim Light Ruin Your Eyes?" Healthportal. N.p., 10
July 2006. Web. 24 June 2014.
Edmonds, Molly. "Eye Strain and Reading in Dim Light“
HowStuffWorks. N.p., n.d. Web. 24 June 2014.
Smith, Michael W. "Reading in Dim Light." WebMD. N.p., 1 May 2008.
Web. 20 June 2014.
Staff, Cleveland Clinic. "Your Eyes: Separating Fact from Fiction."
Cleveland Clinic. N.p., 2009. Web. 20 June 2014.
Staff, Mayo Clinic. "Eyestrain." Mayo Clinic. Mayo Foundation for
Medical Education and Research, 19 Sept. 2012. Web. 24
June 2014.
Vreeman, Rachel C., and Aaron E. Carroll. "Medical Myths." British
Medical Journal, 22 Dec. 2007. Web. 22 June 2014. \
http://funeyetest.com/snellen-chart-printable/
http://www.recapo.com/dr-oz/dr-oz-advice/dr-oz-reading-in-thedark-nosebleeds-health-myths-debunked/
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