How do we see?

Human eye is like a camera. When you take a picture with the camera, the lens allows light to pass through and focuses it on the film. When the light hits the film, picture is taken. Our eye works in the same way. The light rays from the object passes through the cornea, and lens which focus the light on the retina. On the retina an inverted image of the object is formed. Once light energy hits the retina, the photosensitive enzymes trigger a chain of impulses that travel through the optic nerve and reach the brain. Brain will read the information from both eyes, convert the electrical impulses into light impulses and fuse both images from the two eyes. That's how we see!

Vitreo Retinal_clip
Anatomy of Eye

What is retina?

Retina is the innermost photosensitive layer of the eye.
It is connected to the brain via the optic nerve.

What are the parts of retina?

Macula (central retina) - appreciation of fine details, reading and color vision Peripheral retina - functions for night Vision

What are the symptoms of retinal disease?

  • Sudden or gradual decrease in
  • Loss of field of vision
  • Flashes of light
  • Floaters
  • Objects appearing distorted (Metamorphopsia)
  • Night Blindness

When should one consult a retinologist?

Whenever patient has any of the above mentioned symptoms he is advised to have an immediate check up with a retina specialist.
Regular eye examinations if the patient is diabetic, hypertensive and over forty years.

What are the diseases that affect the retina?

Common diseases include :

  • Diabetes mellitus
  • Hypertension
  • Age related macular degeneration
  • Myopia
  • Infectious diseases
  • Heriditary degeneration
  • Congenital degeneration
  • Rarely drugs used for some systemic diseases affect the retina

What are Floaters?

You may sometimes see small specks or clouds moving in your field of vision. They are called floaters. You can often see them when looking at a plain background, like a blank wall or blue sky. While these objects look like they are in front of your eye, they are actually floating inside. What you see are the shadows they cast on the retina. Floaters can have different shapes: little dots, threads, circles, lines, clouds or cobwebs .

Vitreo Retinal_clip
Eye Floaters

What causes floaters?

When people reach middle age, the vitreous gel may start to shrink, forming clumps or strands inside the eye. Posterior vitreous detachment (PVD) : The vitreous gel pulls away from the retina, causing a posterior vitreous detachment. It is a common cause of floaters. PVD is more common for people who :

  • Are shortsighted or myopes ;
  • Have undergone cataract operations;
  • Have had YAG laser of the eye;
  • Have had inflammation inside the eye / any trauma
  • Infectious diseases
  • Heriditary degeneration
  • Congenital degeneration
  • Rarely drugs used for some systemic diseases affect the retina

Are floaters ever serious?

The retina can tear if the shrinking vitreous gel pulls away from the retina. This sometimes causes a small amount of bleeding in the eye that may appear as new floaters.

A torn retina is always a serious problem, since it can lead to a retinal detachment. You should see your retina specialist as soon as possible if even one new floater appears suddenly or you see sudden flashes of light or if you notice other symptoms like the loss of side vision.

What can I do about Floaters?

Floaters can get in the way of clear vision, which may be quite annoying, especially if you are trying to read. You can try moving your eyes, looking up and then down to move the floaters out of the way.

While some floaters may remain in your vision, many of them will fade over time and become less bothersome. Once your retina is examined and everything is normal, you can ignore the floaters.

What causes flashes of lights?

When the vitreous gel rubs or pulls on the retina, you may see what look like flashing lights or lightning streaks. You may have experienced this same sensation if you have ever been hit in the eye and seen "stars." The flashes of light can appear off and on for several weeks or months. As we grow older, it is more common to experience flashes. If you notice the sudden appearance of light flashes, you should visit your Retina specialist immediately to see if the retina has any problem.

What is the treatment of a retinal tear / hole ?

If the tear has not caused a retinal detachment(RD) then a laser is done surrounding the hole / tear to seal it. This reduces the risk of RD. However you need to regularly follow up with a retina specialist as new holes / tears can still form.

Retinal Tear

Vitreo Retinal_clip
Vitreo Retinal_clip

What is Myopia?

  • Myopia is also known as shortsightedness.
  • It is a disorder in which a person cannot focus distant things clearly.
  • The light rays from an object are focused in front of the retina, making them look blurred.
  • It is corrected with minus numbered lenses / Lasik surgery.

How does myopia affect the retina?

  • Myopia can affect the retina in the following ways.
  • Myopes have larger eye balls and can develop retinal thinning and degeneration in the peripheral parts of the retina, these occur due to stretching of the globe.
  • These degenerations are prone to progress and later may form holes or tears in the retina.
  • These retinal holes or tears if not treated can lead to retinal detachment, which will cause sudden loss of vision and will require major surgery at the earliest, to prevent further loss of vision.
  • Sometimes the central part of the retina (macula) may be affected by macular degeneration or choraidal neovascular membrane.