Download Low glutathione reductase and peroxidase activity in age

Low glutathione reductase and peroxidase activity791
in age-related macular degeneration
BritishJournal ofOphthalmology 1994; 78: 791-794
Low glutathione reductase and peroxidase activity
inSteven
age-related
macular
degeneration
M Cohen, Katherine
L Olin, William
J Feuer, Leonard Hjelmeland, Carl L Keen,
Lawrence S Morse
Steven M Cohen, Katherine L Olin, William J Feuer, Leonard Hjelmeland, Carl L Keen,
Lawrence S Morse
Patients and methods
Abstract
Age-related macular degeneration (ARMD) All patients examined in the UC Davis Departmay result from events initiated by reactive ment of Ophthalmology by the authors (LM and
oxygen species. Blood samples from 18 SC) from September 1989 through September
andconsidered
methods for this study. Thirty six
Abstract
patients with ARMD and 18 similarly aged Patients
1992 were
macular
Age-related
All
patients
examined
thetheUC
Davis
degeneration
(ARMD)
Departcontrols were analysed for activities of impor- subjects were entered in
into
study
based
on the
of Ophthalmology
may
from events
reactive ment
bystudy
the authors
by reductase
(LM andby
tant result
antioxidants.
Blood initiated
glutathione
was approved
criteria
listed below. This
Blood
18 SC)
September
oxygen
through
September
sampleswithfrom
UC Davis,
human1989
subjects
committee.
Subactivity species.
was lower
in patients
ARMD
the from
1992
ARMD
were
considered
for
this
with
and
18
patients
study.
Thirty six
aged
similarly
or a
compared with controls (p=0·03S). The activ- jects with diabetes, a major systemic disease,
controls
for activities
of imporentered into
basedexcluded
on the
studywere
analysedperoxidase
glutathione
(p=0·18)
and subjects
ities of were
visuallywere
compromising
eyethe
disease
listed
below.
This study
was approved
tant
antioxidants.
Blood glutathione
by
erythrocyte
superoxide
dismutasereductase
(p=0·29) criteria
from the
study.
Patients
with visually
significant
was lower
in patients
ARMD
UC Davis,
committee.
subjectsalong
activity
the twowith
groups
by a the
were similar
between
cataracts
werehuman
also excluded
with allSubindiwith taking
a major
The regresactiv- jects
diabetes,
compared
systemic or
a
disease,
viduals
zinc
supplements
high or
dose
Student'swith
two controls
sample t(p=0035).
test. Logistic
ities
of
and
visually
glutathione
compromising
eye
disease
were
peroxidase
excluded
(p=018)
sion was used to determine which enzyme vitamin supplements. However, subjects taking
the study. Patients
dismutase
with visually
erythrocyte
superoxide
(p=029)
activities were
associated
with ARMD
after from
a multivitamin
supplement
were notsignificant
excluded.
were
similar
cataracts
between
the
two
were
also
excluded
withcontained
all india
along
groups
by
adjusting for possible confounding variables: These multivitamin supplements
viduals
taking
zinc
or
dose
supplements
high
two
t
test.
Student's
sample
Logistic
regressmoking history, age, multivitamin use, and 100% to 200% of the recommended daily dietary
supplements.
takingC
to determine
which reductase
was used disease.
sion
enzyme vitamin
of vitaminHowever,
A (5000 subjects
IU), vitamin
allowances
cardiovascular
Glutathione
activities
multivitamin
were associated
with ARMD
after a (60
supplement
mg), and vitamin
E (30 were
IU). I'not excluded.
activity (p=O·OS)
and glutathione
peroxidase
for
variables:
These
multivitamin
adjusting
possible
contained
supplements
confounding
Patients included in the ARMD group
had a
activity (p=O·06S) were significantly associated
to 200%
multivitamin
smoking
the recommended
history,
age,analysis.
use, andof 100%
daily
dietary
The relation
of 20/40 or worse
and
had to
Snellen
visualof
acuity
with ARMD
by this
cardiovascular
of vitamin
A (5000 IU), vitamin
disease. and
Glutathione
reductase
C
glutathione reductase
glutathione
peroxi- allowances
10 ophthalmoscopically
visible
have at least
and
and
vitamin
activity
(60
E
(p=0.05)
glutathione
mg),
peroxidase
(30
IU).'9
dase activity to ARMD merits further study. macular drusen, characteristic pigmentary geoin the subretinal
ARMD group
had a
Patientsatrophy,
includedand/or
activity
(p=0 065) were
associated graphic
(BrJ Ophthalmoll994;
78: significantly
791-794)
neovascular
with ARMD by this analysis. The relation of Snellen
visual
of20/40
or
worse
and
had
to
acuity
membranes. Subjects whose visual loss may have
glutathione reductase and glutathione peroxi- have
least 10 ophthalmoscopically
to a media opacityvisible
were
been atsecondary
dase
to ARMD
merits further
activity macular
drusen, characteristic pigmentary geostudy.
Age-related
degeneration
(ARMD)
is a macular
excluded.
78:
Ophthalmol
1994;
791-794)
(BrJ
and/orconsisted
subretinal
neovascular
graphic
atrophy,
leading cause of irreversible vision loss in the
The control group
of subjects
who
have
whose visual loss mayvisible
Subjects
United States, United Kingdom, and other membranes.
had fewer than
two ophthalmoscopically
to each
a media
secondary
were
developed nations. l -6 This disease affects been
macular
drusen in
eye andopacity
an associated
excluded.
Age-related
macular
degeneration
(ARMD)
is
a
20-30% of people over the age of 75. 17 Since this Snellen visual acuity of 20/30 or better in both
leading
irreversible
The control
vision loss
in the eyes.
subjects towho
sectioncause
of the of
population
is expected
to increase
these consisted
patients of
presented
the
Most ofgroup
United
had
United
fewer
than
two
visible
States,
and
other
Kingdom,
ophthalmoscopically
dramatically during the next century, ARMD is a clinic with refractive problems.
nations."'
druseninintheeach
andasked
an associated
developed
disease
affects macular
eyewere
Participants
study
a standard
of severe
and growing
public health
problem This
20-30%
of people
over the age of 75. 7 Since this
in both
of 20/30
orhistory
better questionacuityThis
8 Although
questions.
patient
series ofvisual
proportions.
some risk factors for Snellen
section
of
the
is
population
Most
of
these
expected
to
increase
the
eyes.
patients
presented
ARMD have been identified, its cause remains naire focused on previously identified risktofactors
the next century,
clinic
with
refractive
dramatically
ARMDofisthe
a
during
problems.
An improved
understanding
unknown. 19-12
for ARMD.· Each subject had visual acuity
health
in thecorrection,
public
of severe
asked a standard
and growing
Participants
study wereslit-lamp
aetiology
andproblem
pathogenesis
of ARMD
at the testing
with best
examinaproportions.8
Although
some
risk
factors
series
of
This
for
questions.
patient
history
questioncellular and biochemical level is crucial to devel- tion noting any media opacities, and applanation
ARMD
have beentreatment
identified,and
its cause
focused on
risk factors
remains
previously
oping improved
hopefully
even naire
The
fundus identified
was examined
in all
tonometry.
University of California,
' 12 An improved understanding ofthe for
unknown.
ARMD.9
visual acuity
Davis, Sacramento, USA
prevention of this disease.
subjects
usingEach
eithersubject
contact had
or non-contact
lens
and suggested
aetiology
pathogenesis
ARMD
with best Fundus
the testing
examinacorrection,
slit-lamp were
It has been
thatof
ARMD
mayatresult
biomicroscopy.
photographs
taken
Department of
cellular
biochemical
is crucial
to develnoting
any media
opacities, and
applanation
Ophthalmology
in partand
from
a cascadelevel
of events
initiated
by tion
in most
patients
and fluorescein
angiography
was
SMCohen
oping
improved
treatment
and
hopefully
The
even
fundus
examined in all
tonometry.
of
University California,
7' 13 14 These reactive done only when clinicallywas
reactive
oxygen
species.
indicated.
LSMorse
USA
Davis, Sacramento,
of thismay
disease.
prevention
contact or non-contact
oxygen species
damage lipids in the outer subjects
of examination,
venous bloodlens
was
At theusing
timeeither
L Hjelmeland
It has been
suggested that ARMD
result biomicroscopy.
may
Fundus photographs
were
taken
Department of
of
photoreceptors
and
lead
to
progressegments
drawn
into
a
heparinised
tube
free
from
trace
Department
of
Nutrition
Ophthalmology
insive
from a cascade
events
part
initiated
by inelement
most patients
and fluorescein
was
of the of
retinal
pigment
epithedeterioration
contamination.
Those angiography
that processed
the
M Cohen
S KLOlin
9 314 These reactive
reactive
oxygen
species.7
done
when
indicated.
only
clinically
CLKeen
L S Morse
lium (RPE).· 15 Others propose that circulating blood and performed the assays were masked to
in the
oxygen
damage
the chorioAt subjects'
outer
the time of
venous
bloodblood
was
examination,
LDepartment
Hjelmeland of
reactivespecies
oxygenmay
species
couldlipids
damage
the
diagnoses.
Aliquots
of whole
Biostatistics,
the
Bascom
of
and
lead
to
segments
photoreceptors
drawn
progresinto
a
tube
free
from
trace
heparinised
Department of Nutrition
capillaris and lead to ARMD. 13 Deficiencies of were stored at - 70°C for subsequent analysis of
sive
KPalmer
L Olin Eye Institute,
deterioration
of the
retinal
pigment
epithecontamination.
that processed
the
select
trace elements,
such
as zinc,
have also
been element
glutathione
peroxidase Those
and glutathione
reductase
Miami,
USA
C L Keen
lium
(RPE).9'5inOthers
that circulating
and performed
the assays
to
W J Feuer
implicated
the propose
vision loss
caused by blood
activities.
The remaining
bloodwere
was masked
centrifuged
of
Department
reactive
oxygen species could damage the choriothe
of
whole
blood
subjects'
diagnoses.
Aliquots
ARMD.I6--18
Correspondence to:
at 1700 g for 20 minutes, and plasma fractions
the Bascom
Biostatistics,
Lawrence S Morse,
MD,
and leadwetoreport
capillaris
Deficiencies
of were
ARMD.'3
for subse'quent
-70°C
of
analysiswere
Accordingly,
the results
of a casewerestored
storedat at
- 70°C.
Red cell lysates
Palmer
Eye Institute,
Department
of
select
trace
such
as
have
also
elements,
zinc,
been
and glutathione
glutathione
peroxidase
USA
Miami,
Ophthalmology, UC Davis,
control study of patients with ARMD aimed at prepared by diluting packed
red bloodreductase
cells with
Alhambra Boulevard,
W1603
J Feuer
in thealterations
vision inloss
implicated
caused
by activities.
blood was
remaining
centrifuged
detecting possible
enzyme
activities
an equal The
volume
of distilled,
deionised
water,
Sacramento, CA 95816, USA.
to:
'8
ARMD.'
Correspondence
atmixing
1700 gand
for
20 minutes, and
fractions
plasma
which
have
critical
roles
in
cellular
defence
1700
g;
the
supercentrifuging
at
AcceptedSfor
publication
Lawrence
Morse,
MD,
- 70°C.
the results of a case- were
Accordingly,
report
celluntil
were
lysates
15 June 1994
of
against
reactivewe
oxygen
species
Department
natesstored
were atstored
at Red
- 70°C
used
for
Ophthalmology, UC Davis,
1603 Alhambra Boulevard,
Sacramento, CA 95816, USA.
Accepted for publication
15 June 1994
control study of patients with ARMD aimed at
detecting possible alterations in enzyme activities
which have critical roles in cellular defence
against reactive oxygen species
prepared by diluting packed red blood cells with
an equal volume of distilled, deionised water,
mixing and centrifuging at 1700 g; the supernates were stored at - 70°C until used for
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Cohen, Olin, Feuer, Hjelmeland,
Hielmeland, Keen, Morse
792
determining erythrocyte superoxide dismutase
activity.
Analytical grade chemicals and reagents were
purchased from Sigma Chemical Co (St Louis,
MO, USA) unless otherwise noted. Blood glutathione peroxidase activity was measured accord20) and
ing to the methods of Lawrence and Burk
Burk20)
Jensen. 21 Selenium dependent
Agergaard and Jensen.2'
glutathione peroxidase activity was measured by
using 55 mM hydrogen peroxide in the assay
system. Blood glutathione reductase activity was
measured as described by Rogers and Augusteyn. 22 Following the extraction of haemoglobin
teyn.22
from the red cell lysates, superoxide dismutase
activity was determined according to Marklund
and Marklund.23
Marklund. 23 Haemoglobin concentrations
were determined by the cyanomethaemoglobin
colorimetric procedure (Sigma Diagnostic Kit
No 525).
Results are presented as the mean (SEM).
p Values were computed with Student's two
sample tt test. Backward stepwise multiple logistic regression was used to determine what variables were significantly related to the subjects'
disease status. Variables were removed from
models if their maximum likely p values were
greater than or equal to 01.
0·1. p Values were
calculated with maximum likelihood methods
while confidence intervals were obtained from
asymptotic standard errors. Enzyme activities
were fitted as continuous variables.
Table 1I Historical profile ofpatients with age-related
macular degeneration (ARMD) and controls
Control
No(%)
No
(%)
ARMD
No(%)
18
74 (60--96)
(60-96)
11 (61)
4 (22)
4 (22)
10 (59)
6(35)
6 (35)
6 (35)
3 (17)
3 (17)
11 (61)
18 (100)
Total patients
Average age (range)
Ever smoked
Currently smokes
Stroke
Hypertension
Angina
Myocardial infarct
Multivitamin (currently)
Family history of ARMD
Female
White
18
76 (68-87)
9 (50)
2 (11)
2 (11)
8 (44)
2 (11)
0(0)
0 (0)
7 (39)
11 (6)
8 (44)
18 (100)
Table 2 Examination profile ofpatients with age-related
macular degeneration (ARMD) and controls
ARMD Control
Visual acuity, right eye*
20/80
20/20
20/20
Visual acuity, left eye
20/200
20/20
Visual acuity, worse eye
20/20
20/300
Visual acuity, better eye
20/60
20/20
Hglt
Intraocular pressure, right eye (mm Hg)t
(0 9) 16 (0
6)
15 (0'9)
(0'6)
Intraocular pressure, left eye (mm Hg)t
(0 9) 15 (0
6)
16 (0'9)
(0'6)
Systolic blood pressure (mm Hg)t
134 (4)
140 (5)
Diastolic blood pressure (mm Hg)t
77 (2)
75 (2)
Pseudophakia:j:
Pseudophakia:
55 (28)
2 (11)
Blue irist
iris:j:
77 (39)
11 (61)
*
* Values are expressed as geometric mean of standard Snellen
units. '
t Values are expressed
expressed as mean (SEM).
(SEM).
No (%).
t:j:No(%).
Table 3 Blood antioxidant enzyme activities
'Fable
ARMD
Hb-')')
. Erythrocyte superoxide dismutase (units mg HbBlood glutathione reductase (nmol NADPH oxidised
min-' mg Hb-')
Blood glutathione peroxidase (nmol NADPH oxidised
min-'mgHb-')
min-' mgHb-')
Values are expressed as mean (SEM).
p Values are from two sample Student's tI test.
lest.
Control
Control
0 930 (0'04)
(0-04)
0·930
0-884 (0'02)
(0 02)
0·884
p Value
0-29
o·
29
3-81
HI (0-39)
(0' 39)
5 09 (0
43)
5·09
(0'43)
0-035
0'035
10-3
10'3
(0 72)
(0'72)
11 5
11'5
(0-54)
(0'54)
0-18
0·18
Results
Historical profiles of ARMD and control subjects
are presented in Table 1. The mean age of the
control group was 74 years, ranging from 60 to
96; the mean age of the ARMD group was 76
years, ranging from 68 to 87.
Results from the clinical examination are presented in Table 2. Subjects in the ARMD group
had poor visual acuity with a geometric mean
Snellen visual acuity of 20/80 right eye, 20/200
left eye. In contrast, the control group had
excellent visual acuity with a geometric mean
Snellen visual acuity of 20/20 in both eyes.
Comparing right eyes, left eyes, better eyes, or
worse eyes geometric mean visual acuity was
significantly poorer in the ARMD group than in
controls (p<O·OOl).
(p<0O001). There was no difference in
degree of lens opacity between the ARMD group
and controls. Five (28%) ARMD patients compared with two (11%) controls were bilaterally
pseudophakic.
Results of antioxidant enzyme activities are
presented in Table 3. Glutathione reductase
activity was significantly lower in ARMD subjects compared with controls (p=0·035).
(p=0035). The
actIVItIeS
activities of glutathione peroxidase and
erythrocyte superoxide dismutase were similar
between the two groups.
Logistic regression was used to determine
which of the antioxidant enzyme activities were
associated with disease status after adjusting for
possible confounding variables: smoking history, age, multivitamin use, and cardiovascular
factors including stroke, hypertension, angina,
myocardial infarction. All six patients with myocardial infarction were in the ARMD group
(significant by two tailed Fisher's exact test,
p=0'019) so these cases were excluded from the
p=0-019)
logistic regression analysis. The only variables
which were found to be significantly related to
disease status by logistic regression analysis were
glutathione reductase activity (p=005)
(p=0'05) and
glutathione peroxidase activity (p=0·065).
(p=0065). The
odds ratios associating decreased enzyme activities with ARMD were 1'63
1 63 (95% confidence
interval=1
0 to 2'8)
2-8) for glutathione reductase
interval
= 1'0
1 36 (95% confidence interval=1
interval = 1·0
and 1'36
0 to 2-0)
for glutathione peroxidase.
Discussion
Given that the prevalence of ARMD is strongly
correlated with age, it is reasonable to speculate
that the deterioration of the neurosensory
macula, the RPE, and the choriocapillaris in
ARMD may be secondary to mechanisms associated with the aging process. While the process of
aging is poorly understood, several theories have
been proposed to help explain events leading to
decrease viability and eventually death in a
seemingly time programmed manner. One of the
leading theories of aging links damage caused by
reactive oxygen species to several known aging
processes.24
processes. 24 Reactive oxygen species are molecules which contain an unpaired electron making
them highly reactive. This high reactivity leads
to toxic effects on more stable molecules. Reactive oxygen species are produced in all tissues
during aerobic metabolism and they can also be
formed by photochemical reactions. 525
IS 2S Since the
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Low glutathione reductase and peroxidase activity in age-related macular degeneration
retina is metabolically very active, exposed to
high oxygen concentrations, and exposed to
focused light energy, it is subject to high concentrations of reactive oxygen species. Some of the
toxic effects that these reactive molecules have no
healthy surrounding tissues are a decline in
cellular function caused by reduced enzyme
activities, increased error rates in nucleic acid
metabolism, damaged membranes, and accumulation of undigestible deformed cellular material
in lysosomes.
lysosomes.2"25
In the eye, antioxidant damage is correlated
with senile cataract and exudative macular
2627 We did not include any patient
degeneration.
degeneration.2627
in this study with a visually significant cataract.
The higher incidence of pseudophakia in the
ARMD group (28%) compared with controls
(11
( 11 %), however, may imply that ARMD subjects
developed more visually significant cataracts
than controls. Although several large epidemiological .studies have investigated the relation
between senile cataract and ARMD, their association remains controversial.9-12
controversial.9'2 14'4
The body has several defences against damage
induced by reactive oxygen species. In this
study, we focused our attention on three
enzymes, erythrocyte superoxide dismutase,
glutathione reductase, and glutathione peroxidase, which serve key functions in the elimination of reactive oxygen species. We found no
difference in activity of erythrocyte superoxide
dismutase in ARMD subjects versus controls.
We did, however, find significantly low blood
actlvitIes in ARMD
glutathione reductase activities
patients compared with controls. In addition, a
multiple logistic regression analysis showed that
ARMD patients were more likely to have lower
levels of both glutathione reductase and glutathione peroxidase.
Glutathione peroxidase can reduce hydrogen
peroxide and a variety of organic peroxides using
glutathione as an electron donor.24 Therefore,
low glutathione peroxidase activity may render
patients with ARMD susceptible to damage from
reactive oxygen species. Glutathione peroxidase
activity is dependent on selenium. Interestingly,
a recent case control study found a borderline
association between ARMD and low serum
selenium concentrations; however, no such association was found in the Eye Disease Casereport. 2728
Control Study report.27
28
Recently, a decreased glutathione reductase
activity in lens epithelial cells was shown to be
associated with senile cataract.29
cataract. 29 Although glutathione reductase is not directly an antioxidant, its
proper function is essential to the maintenance of
available reduced glutathione, a potent scavenger of reactive oxygen species. Following its
reaction with a reactive oxygen species, glutathione is oxidised and subsequently returned to
its reduced state by glutathione reductase.24
Low.
reductase. 24 Low
glutathione reductase activity can occur for at
least two reasons. Firstly, genetic variants of the
enzyme exist with variable activity. These variations have been quantified in several populations and range in prevalence
prevalence from 0·3%
to
03% to
22%.30 Secondly, riboflavin deficient individuals
22%."
are
are characterised by lower than normal glutathione reductase activity.3'
activity. 31
The Eye Disease Case-Control Study pre-
793
793
sented evidence that antioxidant blood levels
may be associated with a decreased risk of
developing neovascular ARMD.
ARMD.2727 Similarly, our
data would suggest that individuals with low
glutathione reductase activity and glutathione
peroxidase activity are at increased risk of developing ARMD. Despite current evidence that
decreased activity of blood antioxidant enzyme
activity is associated with ARMD, it is premature
to recommend the use of antioxidant vitamin
supplements for patients with ARMD. The AgeRelated Eye Disease Study is conducting a long
term randomised clinical trial to evaluate the
effect of vitamin and mineral supplements on the
development of ARMD.
Supported in part by a grant in aid from Fight for Sight, Inc,
Research Division of the National Society to Prevent Blindness,
and NIH grant DK35747.
SUTV OphthalI1 Framingham Eye Study. Macular degeneration. Surv
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IM, Allan D, Foulds WS. Common causes of
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3 Grey RH, Burns-Cox CJ, Hughes A. Blind and partial sight
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4 MacDonald AE. Causes of blindness in Canada. Can Med
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55 Rosenberg T. Prevalence of blindness caused by senile macular
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Nutr
ophthalmology
History of
ofophthalmology
Eyesight and the public services
Around the 1880s, eminent British ophthalmologists became concerned with matters which
they sincerely believed would save hundreds of
lives. This was no technical innovation, but
merely the institution of proper sight testing for
those who piloted boats, trains, and planes. At
that time, the official requirements were lax -ships required only a 'percentage of seamen' to
have 'approximately normal' vision and officialdom seemed completely oblivious of the dangers
of defective sight.
Ophthalmologists thus felt duty bound to
instruct the government and regulatory bodies,
and those arriving by horsedrawn cab for the
meeting of the Ophthalmic Society on 9 March
1882 would have been party to the following
debate: W A Brailey, dressed in the customary
top hat and frock coat, opened with the stateof vision at sea' drawn up by
ment that the 'Tests ofvision
the International Medical Congress in 1881 were
somewhat inadequate, yet had been opposed on
the grounds that 'defects of vision have no
practical interest'. Presumably, murmurs of dissent were heard in the gas-lit room.
To refute this, Dr Fitzgerald recounted a case
whereby a seaman was promoted to captain and
on his maiden voyage ran into and sank another
vessel while coming into port. He was reprimanded and demoted for 6 months, then reinstated. Steering into port on his second voyage
he ran down a steamer lying at anchor, and at
the subsequent tribunal, he was dismissed in
disgrace and obtained a post on a smaller vessel.
By interviewing the man and his colleagues,
Fitzgerald ascertained that his vision was so
impaired that he had 'long been .unable to
recognise street names and the numbers on
omnibuses' .
omnibuses'.
It was agreed that testing of both colour and
acuity should be done, preferably by someone
medically qualified, on all sailors involved in
signalling and lookout. Although it was noted
that a member of parliament had promised to
raise the matter in the House during the current
session, feelings were still running high 3 years
later at the meeting of January 1895. Then, Mr
Bickerstaff reported the case of the Iron Duke
which, sailing in convoy, altered its course to
avoid a ship seen ahead by one of the five
watchmen. This caused it to collide with the
. Vanguard, and a quarter of a million pounds'
worth of equipment sank to the bottom. During
the inquiry, the First Sea Lord heard with fury
that the only lookout man to see this 'phantom
ship' had defective vision,
VISIon, having twice been
treated for blindness. Parliament rose up
in wrath at this, as did the ophthalmologists
who sent an urgent deputation, via the British
Medical Association, to the Board of Trade.
Seventy years later, in 1953, the great increase
in commercial air travel led the next generation
of eminent ophthalmologists to consider the
question of pilots' vision, the Civil Aeronautics
Administration having announced (unsurprisingly) that candidates with normal vision were
more likely to succeed at flight training. However, it was concluded that candidates with
defective vision managed quite well if they lived
to become suitably experienced. Therefore, the
CAA decided to accept future trainees with
defective vision, providing that their performance on landing was scrutinised before awarding
them a licence! The ophthalmologists had no
quarrel with this, but considered that possibly
central and peripheral vision should be tested
separately, as diseases such as retinitis pigmentosa could affect the latter only. (It was commented that this affliction
afffiction made approach shots
at golf rather difficult.) However, one ophthalmologist knew an Imperial Airways pilot with
retinitis pigmentosa who asserted that the worst
moments of his day were crossing Victoria
station in the mornings and evenings. The
company concluded that high visual acuity may
not, in fact, be paramount in flying. (NB For
those who feel worried, the CAA now insists on
6/9, 6/9 with satisfactory colour and peripheral
vision.)
With regard to trains, the Snellen test was
employed to yield a standard of vision allowing a
driver to see the rails up to the next curve, and for
those who drove electric trains in a closed cabin,
spectacles could be worn. This was felt to be
satisfactory. With visual standard for motor
drivers, mortality statistics (15 fatalities a day)
raised cries of 'something must be done'
done',, until it
was stated that more accidents occurred in the
home. 'To be logical, therefore, we should not
stay at home, but should seek the relative safety
of our motor cars,' stated the President, and
having apparently exhausted their ire on ships
and planes, the company turned to other matters.
FFROMAN
ROMAN
Brailey WA. Tests of vision at sea. Trans Ophthalmol
Soc UK 1882;
OphthalmolSoc
1882;
2: 184-97.
Mackay G. Eyesight and the public services. Trans Ophthalmol Soc
UK 1895;
1895; 15: 199-205.
Visual requirements in relation to modern travel. Trans OphthalOphthalmol Soc UK 1953; 73: 334-45.
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Low glutathione reductase and peroxidase
activity in age-related macular degeneration.
S M Cohen, K L Olin, W J Feuer, et al.
Br J Ophthalmol 1994 78: 791-794
doi: 10.1136/bjo.78.10.791
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