Interior 2_2006.qxd - Oftalmologia.ro

INTRODUCTION
The lens represents a very complex structure
consisting of water, carbohydrates, lipids, proteins
and oligoelements. The current studies show that the
biochemical mechanisms in age related cataract are
not entirely understood.
METHOD
In our study 72 lenses were taken for biochemical
examinations.
The study included 3 groups of lenses. The first
group (31 lenses) consisted of mature age related
cataracts, the second group (31 lenses) with incipient
age related cataracts and the third group (10 lenses)
with normal lenses. The normal lenses were take
from clear enucleated eyes with choroidal melanoma.
Opaque lenses with initial and mature cataract were
obtained by extracapsular extraction and phacoemulsification
techniques. The visual acuity of patients
with initial cataract was between ½ and 1/6; the
visual acuity for patients with mature cataract was
lower than 1/6. The mean age of the patients was 60
years and their serum biochemical profile was in the
normal limits. The selected patients were chosen for
"healthy" reasons, without diabetes mellitus or other
serious diseases. Some of them had arterial hypertension
under suitable treatment.
Each lens has been put separately on a strip of
celluloid which was kept on ice. After that, the lenses
were weighed at laboratory balance and then mixed
into a glass bottle with a balanced solution of PO4
M/15 until at + 4 0
C until homogeneous samples were
obtained. The balance solution performed a mixture
lens dilution about 50 mg of lens tissue/ml. The samples
were centrifuged to centrifuge cups of a refrigerated
centrifuge at 4000 rpm for 10 minutes. The
supernatant was decantated from the sediment. Each
supernatant was refrigerated until examinations.
RESULTS AND DISCUSSIONS
Our results were reported to 100 g of lens tissue.
The examinations were performed at a Randox
Daytona automated chemistry analyzer.
GLUCOSE
OFTALMOLOGIA 2 - 2006
Principle of reaction:glucose is determined after
enzymatic oxidation in the presence of glucose oxidase;
the hydrogen peroxide produced reacts catalysed
by peroxidase, with phenol and 4 aminophenazone
to form a red-violet quinoneimine dye as indicator;
the intensity of the final color is directly proportional
to the glucose concentration and is measured
at 505 nm.
Lens carbohydrate metabolism represents a very
active area of research. Current studies show that:
about 3 % of lens glucose is metabolized by aerobic
pathway, about 5 % is metabolized by pentose phosphate
pathway, about 3-5 % is metabolized by sorbitol
pathway and the more active pathway is anaerobic
glycolysis.
Our study notices that the level of glucose in the
incipient cataract is much higher than in the normal
lens. In the mature cataract the level of glucose is
higher than in the normal lens. What does it means?
It means that in cataract, the glucose with water
(which are provided by the aqueous humor) pass free
through the alterate membranes into the lens nucleus
and the glycolysis mechanism is not functional,
because the lens tissues are altered. The mature
cataract has too little biochemical elements but anyhow
it has more glucose than the normal lens. We
have found that in "normal conditions" with normal
serum glucose, the age related opaque lens glucose
lever is very high just like the levels of lens glucose
from diabetes mellitus.
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