Anna Giulia Cattaneo, M.D.
University of Insubria, DBSF, via J-H. Dunant, 3 - 21100 Varese.
Between sensorial changes reducing autonomy and quality
of life, visual impairment is a most important one, frequently
increased in the elderly. Vision loss usually imposes to the
older person the presence of a home assistant, or the residence
in a nursing home, it can cause accidents and falls, with
devastating consequences on the frailty of the older subjects.
The impact on economical burden, not only the familial one,
but even for the public health care, imposes a careful diagnosis
and the appropriate use of preventive and therapeutic measures,
as requested. The entire eye and its structures can be affected
by age-associated damage. More common pathological conditions
can be summarized as follows.
1. Cornea and conjunctiva can be injured by at least two
pathologies quite common in the older person.
The dry eye is the effect of tears production inadequacy;
in elderly it can be due to multiple factors, unequally injuring
the tears producing structures (meibomian glands, main and
accessory lachrymal glands, and by the goblet cells). This
pathological condition can cause corneal opacities and keratoconjunctivitis,
and it is common enough to be a concern for costs of public
care. Symptoms include ocular discomfort and pain, photophobia,
various degree of visual loss, temporary or permanent. Adequate
strategies must support diagnosis and outcome. Older age (65
years and more) is a generally recognized risk factor. A number
of underlying conditions are associated with dry eye, in particular
malnutrition (vitamins and oligoelements deficiency), autonomic
dysfunction (as seen in diabetes and in Parkinson disease),
infections and inflammations, and their sequel involving lachrymal
glands, or autoimmune disease (in older subjects mainly represented
by the Sjögren's syndrome and the rheumatoid arthritis).
Other causes of keratitis and conjunctivitis (Grave's disease,
use of contact lens or atopic conjunctivitis, as an example)
are not related to the old age, and are out of the limits
of this Editorial.
The second cause of possible traumas for both the cornea
and the conjunctiva is the eyelid retraction, due to chronic
inflammation and infection, dermal sclerosis and alterations
of connective and elastic fibres. This condition substantially
alters the eye physiology, and can damage the eye as a consequence
of inappropriate distribution of the tear film, in addition
to the direct trauma due to the contact with eyelashes.
Preventive measures include adequate treatment of underlying
or associated diseases, improvement of hygiene and nutrition,
early detection and diagnosis of any cause of ocular discomfort,
avoid fatigue and frequent rubbing of eyelids, adequate use,
not misuse, of eye drops. Therapy vary widely, from very simple
measures, as the use of tears replacement, to medication (antinflammatory
drugs, pilocarpine and agents acting on the autonomic system,
immunity depressant, and others), or even surgery, for more
serious cases and complications.
2. Another age-related condition impairing visual acuity
is the cataracts. Senile opacities of the lens can be
due to nuclear sclerosis, cortical and subcapsular (both anterior
and posterior) cataract. Various degrees of visual impairment
are the most important symptoms, to be supported by examination
of the eye anterior chamber. In addition to older age, diabetes
mellitus and overexposure to UV radiation can cause the same
ocular defect: the role of oxidative damage has been postulated
and in part demonstrated in all these conditions. The only
type of cataract associated with the Werner syndrome, an accelerated
aging process due to a genetic defect, is instead subcapsular.
The preventive measures are efficient only if they are long-lasting.
They include protection from UV and ionizing radiation (life-long,
or as long as possible), nutritional measures, like long-term
high intake of vitamin C, A and E and other antioxidant to
the diet, and, of course, a careful treatment of diabetes
mellitus, when present. Eye drops containing N-acetylcarnosine
have been proposed as protective against progression of the
opacity. However, reversion of an incipient cataract is an
improbable purpose, and surgery is the treatment of choice
for established lens opacities. The improvement of visual
acuity is rapid (40-50% after 3 months) and progressive (>80%
2 years later).
3. Glaucoma recognizes a genetic predisposition, however
it is also a well known consequence of diseases (diabetic
retinopathy, vitreous detachment, and cataract), or it can
be iatrogenic: malpractice in medications and ocular surgery
can be responsible of it. Signs and symptoms differ in
acute angle-closure and in open-angle glaucoma. The first
is an emergence characterized by the "red eye",
with conjunctival injection, severe pain and elevated intraocular
pressure, and must be promptly differentiated from other acute
diseases involving the eye (mainly conjunctivitis, iritis
or keratitis). In elder people it can follows distortions
of the anterior chamber due to surgery on the lens, or aphakia.
The open angle glaucoma is by far most common, and has been
recognized as an age-associated condition. Its incidence should
increase in the near future, as predicted by a recent study
(Eur J Ophthalmol. 2007 Jan-Feb; 17(1):45-52). Headache, myopia
and progressive visual impairment can be associated. Preventive
measures include a precocious selection of patients at risk
on the basis of anamnesis (genetic risk is important), precocious
diagnosis, correction of associated diseases, knowledge of
drugs adverse reactions and cautious use of medications. Accurate
asepsis and skill in performing eye surgery, even in minimally
invasive manipulations, are required. Therapy is based on
medication or surgery.
4. Diabetic and hypertensive retinopathies in aged persons
follow the rules and outcome common to their causative diseases.
The prevalence and duration of underlying diseases is positively
correlated with the higher prevalence and severity of retinal
complications in elderly people. Prevention is based on effective
and long-lasting management of diabetes and hypertension,
the choice of drugs must take into account the frailty of
the old subjects and the eventual presence of co-morbidity
and multiple drug intakes. While adequate treatment of hypertension
usually cure also the retinopathy, the macular oedema and
proliferative retinopathy due to diabetes requires laser photocoagulation
to maintain vision. In certain cases, vitrectomy is required.
5. The disease probably more typical of the old age is
the senile macular degeneration. This disease, causing
a progressive and serious visual impairment, is primarily
associated to the aging process in genetically predisposed
individuals. It behaves as a lat-onset inherited disease.
The role of an oxidative damage superimposed to the genetic
trait has been proposed. A damage of the outer segment of
cones associated with altered composition of retinal pigments
is followed by altered properties of the Bruch's membrane
of the choroids and by accumulation of debris, seen at the
ophthalmoscope as whitish extrusions called "drusen".
Choroidal revascularization follows. Their excessive presence
in the macular region is distinctive of senile macular degeneration.
Associated risk factors, in addition to genetics and aging,
are few and poorly documented: cigarette smoking and nutritional
deficiencies, especially of vitamins and zinc, seems to be
supported by some evidence. Preventive measures are not known,
except for safer life style concerning nutritional and not-smoking
habits. Established therapeutic measures are based on laser
photocoagulation. A number of alternative types of treatment,
ranging from anti-angiogenic medications, photodynamic and
low-dose radiation therapy, or surgical intervention for macular
translocation and even embryonic cells transplants have been
experimentally proposed. The disease remains one among the
most important causes of visual impairment and blindness in
older age, in absence of concomitant diseases.
The interested people can eventually read a review, like
that recently appeared in Am J Nurs. 2006 Nov;106(11):52-61.
Other diseases and lesions to the eye and its surroundings
structures, impairing visual acuity but not typically associated
with elderly exceed the limits of this Editorial.
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