Eye Diseases and Eye-related Topics
Introduction Eyesight
is one of the five senses, perhaps the most important one, that keeps us in touch
with the environment. The trigeminal nerve is a powerful nerve that provides the
surface of the eye (the cornea) with sensitive nerve fibers. The optic
nerve supplies the retina with the necessary nerve fibers for visual perception,
like a living light sensitive camera. The structure of the eye is complex and
will be explained below in a brief outline under "eye anatomy". It will
be further detailed where it is needed in each of the subchapters. Children's
eyes are more difficult to assess as they find it more difficult to sit still
and cannot answer questions as precisely as adults. Yet, in order to avoid the
development of a lazy eye, called "amblyopia", they need regular
eye doctor visits as is explained in this link.
Eyelid
Problems (Entropion, Ectropion etc.) When the eye lids loose elasticity
with age the tracking mechanism of the eye lids is abnormal. The lower eye lids
can turn inward (entropion)
or outward (ectropion)
. Similarly, there is a site with more detail of what to do when
the patient has
an entropion. This site shows pictures before and after entropion
surgery that demonstrate what can be done to help these patients get normal looking
eyes with normal eye lid function.
Optic
Nerve ProblemsIntroduction:
The optic nerve forms the whitish/yellow knob that the physician sees through
the ophthalmoscope or the slit lamp at the back of the eye. Physicians call it
the "optic
disc" or in Latin the "papilla". This is where
all of the nerves that collect information from the retinal nerve cells bundle
together and form the beginning of the optic nerve. When the optic nerve leaves
the eye ball (also called "bulb") in the back, it is still within the
eye cavity for a short stretch. This part of the optic nerve is termed "bulbar
portion" or orbital portion of the optic nerve. This terminology becomes
important when it comes to disease conditions. For instance, we will learn
more about "papilledema" below, which is a
swelling of the optic disc or papilla (=edema of the papilla) from high blood
pressure. If there is inflammation of the optic disc, this is called "papillitis"
(="itis" meaning "inflammation", therefore "inflammation
of the papilla). Another term is "retrobulbar neuritis",
which is a nerve inflammation of the bulbar portion (=orbital portion) of the
optic nerve. All of these conditions are explained under the links
of the above table in more detail. I will also deal with
toxic amblyopia (blurred vision from toxins), optic atrophy (atrophy
of the optic nerve) and interruptions of higher optic pathways
at the optic chiasm and in the brain substance.
Retinal Problems |
| Name of condition: | Cause
and description: | | central
retinal artery occlusion | from
a dislodged blood clot in an artery | | central
retinal vein occlusion | occurs
in older persons. Common with glaucoma, diabetes, high blood pressure and blood
clotting disorders | | diabetic
retinopathy | the longer
diabetes has been present , the worse the condition usually is |
| poorly
controlled high blood pressure causes this condition. Also in toxemia of pregnancy |
| macular
degeneration | this condition
is age-related and leads to progressive loss of vision, more common in whites
than blacks; it may be hereditary | | retinal
detachment | occurs in
trauma, with myopia or after cataract surgery (often with a tear); also happens
without a tear in diabetics or in patients with sickle cell disease |
| retinitis
pigmentosa | loss of
night vision, later also blind spots. Sometimes associated with hearing loss (hereditary
form) | | retinopathy
of prematurity | abnormal
retinal blood vessels in prematurely born babies. Depending on the degree, vision
ranges from normal to blindness | Retinal
ProblemsIntroduction: Retinal problems can happen
in a variety of different settings. For instance, diabetes can lead to a diabetic
neuropathy, uncontrolled high blood pressure to a hypertensive neuropathy. But
aging by itself can lead to loss of sight by the development of age related macular
degeneration. All of these conditions and the ones listed in the table above do
lead to loss of vision, either slowly (most conditions) or suddenly (retinal detachment),
all of that without any pain. If a prior eye condition such as uveitis or glaucoma
exists, pain can be present and comes from the preexisting condition, not from
the retinal problem. Signs and symptoms: These are
different for the various conditions and can be found in more detail under the
links of the table above where each retinal problem is described.
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