Vision First July 2018 English

What is the macula?
Macula
General FAQs
The macula is a small spot located in the center of
the retina, which is the light sensitive tissue that
lines the inside of the eye. The macula is made up
of millions of light-sensing cells that collect highly
detailed images at the center of the field of vision,
which are then sent through the optic nerve to the
brain, where it is interpreted as sight. The macula
provides good colour vision and gives us the ability
to see “20/20” (fine details).
What is the fovea?
The fovea is a small depression at the very center
of the macula and is very important as it helps us
to see fine detail and colour. It has a high density
of cones cells, which are photoreceptors that are
active during the day, and provide detailed vision
and colour perception. The fovea is special because
the centre of the field of vision is focused in this
region and visual acuity is highest. When we look
at an object, eye movements let the fovea move
over the object of interest and focus on important
details.
What is the size of the human macula?
The human macula is very small and measures
around 5.5 mm or 0.22 inches in diameter.
How does the macula work?
The macula is the functional center of the retina
where highly detailed images at the center of the
field of vision are collected and sent to the brain
through the optic nerve. Light is focused onto the
macula by the cornea and lens in the front of the
eye. The light is converted into electrical signals
and sent on to the brain. The electrical signals are
interpreted by the brain as sight or vision.
What is macular eye disease?
Macular eye disease is caused by a number of
eye problems that affect the macula. Macular eye
disease results in a gradual loss of sharp, detailed and
central vision, making it difficult to read, watch TV, or see
faces. The peripheral vision or side is usually not affected.
What are the common causes of macular
diseases?
The macula can be affected by a number of causes which
include degeneration, trauma, infection, vascular and
inflammatory problems, etc.
What kind of eye problems can affect the
macula?
Eye problems that can affect the macula include:
• Branch retinal vein occlusion
• Central retinal vein occlusion
• Central serous retinopathy
• Choroidal neovascular membranes
• Cytomegalovirus retinitis
• Diabetic retinopathy
• Histoplasmosis
• Macular degeneration, in either dry or wet forms
• Macular edema
• Macular hole
• Macular pucker
• Macular telangiectasia
• Retinal detachment
• Retinitis pigmentosa
• Retinoblastoma
• Retinopathy of prematurity
• Stargardt disease
• Usher syndrome
What are the types of macular disease?
There are many forms of macular disease, with AMD (agerelated
macular degeneration) being the most common and
juvenile macular dystrophies the most rare. Other macular
conditions include myopic maculopathy, diabetic macular
oedema, punctate inner choroidopathy, and retinal vein
occlusion.
How can macular diseases be
classified?
Macular diseases can be subdivided
into those with and without choroidal
neovascularization (CNV). The layers of
the retinal can be damaged by diseases
like macular degeneration, which leads
to the growth of new blood vessels
(neovascularization) in the choroid layer
of the eye. These abnormal blood vessels
can break through the barrier between the
choroid and the retina and leak or bleed
into the retina leading to blurry, darkened or
distorted vision.
Macular diseases not associated
with CNV include:
• Age-related macular degeneration (dry
type)
• Diabetic macular edema
• Macular hole
• Epiretinal membrane
• Central serous chorioretinopathy
Macular diseases associated with CNV include:
• Age-related macular degeneration (wet type)
• High myopia macular degeneration
• Idiopathic CNV
• Idiopathic polypoidal choroidal vasculopathy
• Chorioditis of various causes
What happens when the macula gets
damaged?
The macula is the central and most sensitive area of
the retina. It provides the important, functional vision
that we need for reading, close work, and to see things
in detail that need a lot of close focus. The macula’s
structure needs to be undisturbed and relatively dry
in order for the images to be clear and vision to be
good. When the cells of the macula deteriorate or get
damaged, the center of the field of view gets affected. In
some cases, the neurosensory retina detaches from the
epithelium. In advanced degeneration, the macula may
bleed and leak fluid, and drusen spots (yellow deposits)
may appear.
How does damage to the macula affect
vision?
Similar to the film in a camera, a healthy retina produces
a clear image. But if the macula is damaged, the image
will not be clear. The macula is responsible for central
(sharp, straight-ahead) vision, which allows you to see
fine details clearly, in your direct line of sight. Whenever
we look at an object, the image focuses on the macula
and the brain builds up details of what we see. When the
cells of the macula deteriorate, images are not received
correctly by the brain, causing distortion of an image’s
lines and size. The center of your field of view (all the
things you see in fine detail) may appear misty, blurry,
distorted, or dark.
How does macular damage affect daily life?
While the rest of the retina provides peripheral vision,
the macula is rich in photoreceptor nerve cells that
enable us to see fine details and colour. The loss of
central vision in macular degeneration can hinder
simple everyday tasks such as the ability to see faces,
read, write, drive, using the stairs, or do close work
such as cooking, dialling a telephone, or working on a
computer.
What are maculopathy and macular
dystrophy?
Maculopathy or macular dystrophy is a condition where
drusen spots, which are yellow deposits that are made
up of lipids (a fatty protein), appear on the macula,
possibly accompanied by some scarring. Drusen spots
indicate that there is some problem with the macula.
Studies show that people with drusen spots (especially
large spots) have an increased risk of developing
macular degeneration.
What are the common symptoms of macular
diseases?
Macula is important for central vision, fine visualization
and colour differentiation. Patients suffering from
macular diseases may experience the following
symptoms:
• Blurring of central vision - This may be characterised
24 Narayana Nethralaya | Ranked Among The Top 10 Eye Hospitals in India Since A Decade www.narayananethralaya.org Narayana Nethralaya | Ranked Among The Top 10 Eye Hospitals in India Since A Decade www.narayananethralaya.org 25