Vision therapy is a term used to develop or improve visual skills, abilities, visual comfort, ease, and efficiency; and change visual processing or interpretation of visual information. The vision therapy program is based on the results of a comprehensive eye examination or consultation, and takes into consideration the results of standardized tests, the needs of the patient, and the patient’s signs and symptoms. The use of lenses, prisms, filters, occludes, specialized instruments, and a computer program is an integral part of vision therapy.

Athletes often have high visual demand. Many sports vision skills include: Hand-eye coordination, improved depth perception eye tracking ability. The sports vision tests that assess how well an athlete sees sometimes also can be used to train athletes and improve visual function.

Vision loss is major issue worldwide and 285 million people are estimated to be visually impaired worldwide out of which 39 million are blind and 246 have low vision. Globally, uncorrected refractive errors are the main cause of moderate and severe visual impairment; cataracts remain the leading cause of blindness in middle and low income countries; diabetic retinopathy, age-related macular degeneration, glaucoma are also leading causes of vision loss.

The amount of image processing going on in the eyeball is astounding. The signals from your retina split into some channels that analyse the image before it reaches the brain. Dual focus on both sharpness and speed is made possible through different processing streams set up in the retina. The eye separates all the visual information into various channels and each channels is taken up different type of ganglion cells which carries information about motion or colour or edges, etc. All these channels are pre-processed by the ganglion cells before actually reaching the brain where final image interpretation happens.

Optic nerve is part of the visual system which connects the eye to the brain. The visual information relays through this tract towards the visual cortex. This visual information triggers a stimulus at the receptive field of a ganglion cell in the retina of the eye which is composed of input from all of the photoreceptors which synapse with it, and a group of ganglion cells in turn forms the receptive field for a cell in the brain.

Colour vision is the ability of an organism or computer to distinguish objects based on the frequencies of the light they reflect, emit, or transmit. Colours are processed and quantified in various ways. A person's perception of colours is an individual process where the brain responds to the stimulus when incoming light reacts with the several types of cone cells in the eye. For instance, tetrachromats see million more colours than a normal person because they have four cone type cells. In essence, different people see the same illuminated object or light source in different ways.

A classic debate on the relation between language and colour perception has been outlined. This debate entails whether human perception of colour is subject to language relativistic effects. This concept focuses on various disciplines beyond linguistics, including visual neurobiology, anthropology of vision, psychology, sociology and cultural relativity.

Ophthalmology is branch of medicine that entails the anatomy, physiology, and diseases of the eye. Vision science deals with a complete scientific understanding of visual system in both humans and other organisms. And together these branches address a multitude of eye diseases and visual system disorders that can be diagnosed, treated and prevented.

Computer vision is a science which learns to mimic the human visual system by acquiring, processing, analysing high quality digital images data from real world. This capability of a computer can be achieved through computational models through understanding the mechanics of eyes and neural pathways of vision. With the development of this technology, devices which aid the visually disordered and blind can be addressed.

Visual perception is the ability to decode the information in the visible light, the resulting perception help us understand the surrounding environment, to recognize patterns, objects and faces. This ability to perceive is affected by various factors like normal development of visual system, psychology, past experience, culture, visual cognitive science, anthropology science, and neuroscience. By considering how relations between persons are framed by culture and played out through the glance, the gaze and other ways of looking, one goes beyond the mechanics of perception to form a better understanding of visual processes.

Visual neuroscience is a sub branch of a bigger conglomerate subject called Neuroscience. This branch takes into account various topics such as organization of visual pathways; subcortical processing; processing in the primary visual cortex, effects of drugs on visual neural pathways, computational modelling of neural pathways of vision, spatial relationships between eye movements, attention and cognition. Insight into this process allows clinical psychologists to gain a greater understanding for what may be causing visual disorders.

The visual system is the part of the central nervous system that is required for comprehending visual details like receiving, processing and interpreting visual information to build a representation of the surrounding visual environment. The visual system involves the eyes, connecting pathways through to the visual cortex, optic nerve, optic chiasm, optic tract, ganglion cells and other parts of the brain. The neural signals initially processed by the retina travel via the axons of the ganglion cells through the optic nerves. Optic nerves from both eyes cross over at the optic chiasm and split based on the visual field and end up in the lateral geniculate nucleus (LGN). From the LGN, the signals continue to the primary visual cortex of the brain for the processing of the visual image.

Visual Memory is the ability to remember or recall the characteristics of a given object place, people or form in a mental image. If we have trouble inputting information into our short term memory, we can’t process it into our long term memory for permanent storage. Children with poor visual memory may often subvocalize as they read because they must rely on auditory input to help them compensate. Thus, the intersection between memory and vision is a particularly interesting domain of research because it concerns both the processes of memory and the nature of the stored representations.

Binocular vision is state of simultaneous vision which is achieved by coordinated use of both eyes so that separate and slight dissimilar images arising in each eye appreciated as single image by process of fusion. It is the most common visual disorders. They are usually associated with symptoms such as headaches, asthenopia, eye pain, blurred vision, and occasional diplopia.

Binocular vision anomalies include:

Diabetic Retinopathy is a progressive micro angiopathy with consequent breakdown of blood retinal barrier resulting in a variety of fundus picture finally leading to blindness. It is an ocular manifestation of systemic disease which affects up to 80% of all diabetic patients.

Low vision as the name indicates the condition linked with abnormal or low eye sight which interferes the daily functioning of a child. Paediatric Low vision could be a cause of various eye diseases such as paediatric glaucoma, paediatric cataract etc. Low vision exam of paediatric is differs based on the age of the child. Visual acuity, refractive error, visual field, eye muscle function and colour vision are the consideration taken by paediatric ophthalmologists to find out the visual function of a child.

Ocular Oncology is a highly specialized and niche facility offering expert care in the treatment various cancerous tumours of the eye and surrounding structures. The commonest tumour of the eye occurs in children and is called ‘Retinoblastoma’. The second most common intra-ocular tumour treated is Choroidal Melanoma which largely occurs among adults; it has advance facilities and expertise in procedures such as Transpupillary Thermo Therapy, Brachytherapy, Local Tumour Resection in the form of Eye Wall Resection for effectively treating this condition. Complex vitreoretinal problems that is associated with some of the other intraocular tumours such as choroidalhemangioma and Von HippelLindauare. The Ocular Oncology is engaged in close interaction and collaborative treatment initiatives with the Ocular Surface Clinic for the management of tumours of the surface of the eye and with the Oculoplasty Department for management of orbital tumours.

Retina is the light sensitive film in the back of the eye. The image is perceived here and transmitted to the brain by the optic nerve. The vitreous is the clear gel that fills the back of the eye. Diseases of retina can affect any age. Premature infants can be affected by a disease called - ROP (Retinopathy of pre-maturity). Heredity and age related degenerations can affect the retina - especially the central most sensitive part of the retina called 'macula'. The retina can detach from the back portion of the eye - a condition called 'Retinal Detachment'. The Vitreous gel can become opaque due to blood - a condition called 'Vitreous haemorrhage'. This condition can occur in diabetics following injury and in other conditions. The treatments available are Medical managements such as Laser Photocoagulation , intravitreal injections and Surgical managements such as Complex Vitreoretinal Surgery.

Orbit and Oculoplasty deals with the management of diseases and abnormalities of the orbit, eyelids and the lacrimal system.  Drooping of the upper eyelid (ptosis) is a common problem dealt by this Department. If the lid droop is very severe especially in young children, it can even lead to lazy eye (amblyopia). Hence correction of the condition is essential for functional and cosmetic improvement. Orbit is the bony cavity enclosing the eye. The orbit can be the seat of tumours that cause protrusion of the eyeball (proptosis). The lacrimal system drains tears into the nose and could be the site of chronic infection (dacryocystitis).

A cataract is a clouding of the lens in the eye. This clouding affects vision. A cataract can happen in one or both eyes, but does not spread from one eye to the other. Most cataracts happen as the result of aging, and they are very common in older people. Cataracts affect vision by creating a cloudy area on the lens of the eye. This cloudy area can get larger over time and cause serious vision problems. The lens helps to focus light on the retina, the light-sensitive tissue at the back of the eye. In a normal eye, light passes through a clear lens to the retina, which turns it into nerve signals that are passed to the brain. The lens must be clear for the retina to receive a sharp image. If the lens is cloudy from a cataract, the image that the brain receives will be blurred. Age-related cataracts can also cause discoloration of the lens. Over time, the clear lens slowly changes to a yellowish or brownish color, which tints vision. This gradual change in tint does not make vision blurry.

Dry eye occurs when the eye does not produce tears properly, or when the tears aren't of good quality and evaporate too quickly. Dry eye can make it more difficult to perform some activities, such as using a computer or reading for an extended period of time, and it can make some environments uncomfortable, such as the air inside an airplane. Other names for dry eye include dry eye syndrome, keratoconjunctivitis sicca (KCS), dysfunctional tear syndrome, lacrimal keratoconjunctivitis, evaporative tear deficiency, aqueous tear deficiency, and LASIK-induced neurotrophic epitheliopathy (LNE).

In some cases, dry eye can cause inflammation of the eye's surface. Without treatment, this can lead to pain, ulcers, or scars on the cornea (the clear, dome-shaped outer surface that covers the center of the eye), and some loss of vision. But permanent vision loss from dry eye is uncommon.

Dry eye can cause the following symptoms in the eye:

Glaucoma is a group of diseases that result in degeneration of the optic nerve and many are caused by increased pressure inside the eye. Glaucoma can lead to vision loss and even blindness.

In most patients, glaucoma occurs when pressure inside the eye is at a level sufficient to damage to the optic nerve. The optic nerve is a bundle of more than 1 million nerve fibers. It connects the retina to the brain. The retina is the light-sensitive tissue at the back of the eye. A healthy optic nerve is necessary for good vision. Glaucoma is one of the leading causes of blindness. Glaucoma causes blindness in little over 12 percent of people with the condition. However, early treatment can often prevent serious vision loss.

There are three main types of glaucoma:

Retinal detachment is a condition in which a layer of tissue called the retina gets lifted or pulled away from its normal position in the eye. The retina acts as a light-sensitive wallpaper in the eye, lining the inside of the eye wall and sending visual signals to the brain. There are three types of retinal detachment. They include:

• Rhegmatogenous – In this type, a tear or break allows fluid to get under the retina and separate it from the retinal pigment epithelium (RPE). The RPE is a layer of cells that nourishes the retina. These types of retinal detachments are the most common. They are also the most dangerous type, since they progress rapidly.
• Tractional - In this type, scar tissue on the retina's surface shrinks and causes it to separate from the RPE. This type of detachment occurs in people with diabetes. It does not progress as rapidly.
• Exudative – In this type, fluid leaks into the area underneath the retina, but there are no tears or breaks in the retina. This type is usually caused by retinal diseases, including inflammatory disorders and injury or trauma to the eye.

Symptoms of retinal detachment include:

Blepharitis is a condition that causes inflammation in the eyelids. Many people have blepharitis. It is also called “granulated eyelids.” There are two types of blepharitis:

• Anterior blepharitis – This type affects the outer front part of the eyelid, where the eyelashes are attached. The two most common causes of anterior blepharitis are bacteria (Staphylococcus) and scalp dandruff.
• Posterior blepharitis – This type affects the inner eyelid, in the moist part that makes contact with the eye. This part of the eyelid contains oil (meibomian) glands. Problems with these glands cause posterior blepharitis.

People with certain skin disorders are more likely to get posterior blepharitis. These disorders include acne rosacea and seborrheic dermatitis (scalp dandruff).

Symptoms are similar for both types of blepharitis. They include:

Conjunctivitis is a medical term for inflammation of the “conjunctiva.” The conjunctiva is a thin, transparent layer of tissue that lines the inner eyelids and outer surface of the eye. While conjunctivitis is more common in children, it can also happen in adults. Conjunctivitis is also called “pink eye” or "red eye."

Conjunctivitis can be acute or chronic depending on the cause of the condition, the symptoms involved, and how long it lasts. Acute conjunctivitis usually goes away in a few days, while chronic conjunctivitis can last much longer, or come back again and again.

Conjunctivitis usually does not cause permanent vision problems. However, in rare cases, it can cause damage if symptoms are severe and are not properly treated.