Anatomy of the Eye

Anatomy and Working of the Eye and Refractive Errors

The eye enables sight – one of the 5 primary senses in the human body. Hence, protecting your eyesight is extremely important. Consuming nutritious meals and regularly visiting your ophthalmologist ensures that you maintain eye health and retain your sight.

Understanding the anatomy of the eye helps you maintain its health. It also allows you to identify any eye problems you may have. Alongside an expert ophthalmologist like Dr Anisha Gupta, you can easily and effectively treat any eye problems you may have with guaranteed results.

Anatomy of the Eye

The Anatomy of the Eye

From the front to the back, 12 parts optimise eye function. Let us explain these to you in order:

Cornea: The clear front window of the eye that transmits and focuses light.
Iris: The part regulating how much light enters the eye by opening and closing the pupil. The iris is also responsible for the colour of the eye.
Pupil: The darker centre that changes size based on how much light there is. It becomes bigger in darker areas and smaller in brighter spaces, operating like the aperture in cameras.
Lens: Much like a camera, the eye also has a lens that focuses light on the retina. It is transparent, but may become opaque due to many causes. Then it is called cataract.
Ciliary Body: The muscle structure located behind the iris, helping the lens focus.
Sclera: The outer white layer surrounding the eye.
Choroid: Present between the retina and sclera, the choroid contains a network of blood vessels lining the back of the eye.
Vitreous Humour: The gel-like clear substance filling the central cavity in the eye.
Retina: The part of the eye that senses light through a layer of nerves. It then creates electrical impulses that pass through the optic nerve to the brain.
Macula: The retina’s central area that contains light-sensitive cells, allowing us to perceive finer details in our line of sight. The macula is responsible for most of the central vision.
Fovea: The centre of the macula, enabling sharp vision.
Optic Nerve: The bundle of more than a million nerve fibres carrying messages from the retina to the brain.

These essential structures ensure that your eye continues to function perfectly. If any of these are affected, the vision is affected.

The Working of the Eye

Understanding the eye’s working is very similar to operating a camera. Much like the camera’s shutter, the eye’s aperture, the pupil, opens or closes depending on the amount of light. In a camera, this light exposes the film at the back of the camera. For the eye – the iris and pupil work together to allow light to the back of the eye.

Our eyesight depends on the transfer of light through the front of the eye (the cornea and lens) to the retina. Together, the cornea and lens focus the light rays onto the retina. The cells in the macula then absorb and convert the light into electrochemical impulses. These are transferred to the brain via the optic nerve. In the process, the optic nerve has to turn the images right side up since the retina perceives the images upside down.

Refractive errors are conditions in which the eye is largely normal in structure, but light does not get focused at the retina. Hence, we need glasses or contact lenses to make the light focus at the right place (retina).

Refractive Errors and Their Types

If you have blurry vision, you may be experiencing a refractive error. A refractive error is when your eye cannot properly bend light and focus it on the retina. It may happen because your eyeball is too long or short, your cornea is improperly shaped, or your lens has aged and become rigid and clouded.

Its symptoms include:

Blurry vision
Difficulty seeing up close or reading
Cross-eyed phenomenon in children

If you experience any of these, please contact an ophthalmologist immediately and seek your course of action. If left untreated, refractive errors could cause further complications in your eye.

There are also different types of refractive errors. The 4 most common are:

Myopia (near-sightedness)

Myopia happens when the eyeball is longer than normal, causing light to focus in front of the retina. It is the most common refractive error in children, and is corrected with minus glasses.

Hyperopia (far-sightedness)

Hyperopia is when the eyeball is shorter than normal, making light focus behind the retina. It is corrected with plus glasses.


Presbyopia involves the lens in your eye hardening with age. The lens loses its flexibility, resulting in an inability to focus on close-up images. Apart from regular refractive corrections, presbyopia may also be corrected through intraocular lens implants (IOLs).


Astigmatism happens due to asymmetric corneal curvature, i.e. when the cornea is curved steeply in one direction.

Refractive errors can be corrected easily and safely with glasses, contact lenses or surgery. With an expert like Dr Anisha Gupta, you get excellent results with accurate diagnoses and effective treatment paths.

Dr Gupta uses the latest techniques and devices for excellent outcomes that minimise downtime and promote a comfortable, speedy recovery!

Contact us today and check your eye health with our expert ophthalmologist!