While someone is working in the computer the blink rate is reduced. If the working place is air conditioned, it causes low humidity and this combined with long working hours with reduced blink rate leads to computer vision syndrome. Place the computer terminal below the level of your eyes, so that you look down at it. Looking up at the screen causes your upper lid to lift and exposes more of the ocular surface to the drying effects of a low humidity air-conditioned environment. Constant, conscious blinking when working on computers can help. Another useful thing to remember is the 20-20-20 rule. Every 20 minutes, one should look away from the screen into the distance (20 feet), for 20 seconds to rest the eye muscles.

Glare screen filters helps to reduce glare from the computer screen. An eye glass with anti reflective coating (AR) is also useful as the AR coating prevents glare and reflections. These may help somewhat, but they will not solve your computer vision problems completely because they only affect glare from the computer screen and not the visual problems related to the constant refocusing of your eyes when working at a computer.

A thorough eye examination is needed to confirm whether your symptoms are due to computer use alone. Examination includes vision assessment and the presence of any refractive error to decide the need to wear glasses for the distance at which the computer screen is viewed. Some may have reduced convergence ( the movement of eyes towards each other for near work) which needs to be treated by exercises. With increasing age, the tone of the muscle inside the eye that allows the natural lens to change shape is reduced. This leads to blurring of vision for near work which needs to be treated with glasses.The work environment and the design ergonomics of the desk and chair will also need to be determined as they can contribute to the symptoms mentioned. In addition to the above the eye lids and tear film status are to be assessed as lid margin disease or dry eyes can worsen the condition.

Make sure your sit in a comfortable chair with a good back rest. Room lighting should be free of glare and from the ceiling rather than from the side walls. Reduce very bright room lights so that the brightness and contrast of the computer screen can be reduced to comfortable levels. Working distance from eye to screen should be set between 50-60 cm. Viewing angle for the screen should be 10 degrees to 15 degrees below straight-ahead gaze position, to minimise the evaporation of tear film.

Follow the 20-20-20 rule. Every 20 minutes, one should look away from the screen into the distance (20 feet), for 20 seconds to rest the eye muscles.

With the advances in the field of Ophthalmology, it is now possible to remove only the affected layers of the cornea instead of replacing the entire, full thickness corneal tissue in selected patients. Avoiding a full thickness corneal transplantation reduces the complications and increase the survival rate of the graft. The various types of surgical procedures include

In this procedure the entire cornea from the patient is removed and replaced with the donor cornea. It is done for patients who have disease involving most or all the corneal layers.

This procedure removes diseased tissue from the back corneal layers called the Endothelium and Descemet membrane. In a healthy cornea, these layers help to keep the cornea dry and prevents fluid accumulation.In conditions where the disease process involves these deeper layers, thy can be selectively removed and replaced with the donor corneal layers.

There are two types of endothelial keratoplasty. The more common type, called Descemet Stripping Endothelial Keratoplasty (DSEK), uses donor tissue to replace about one-third of the cornea. A second type of procedure, called Descemet Membrane Endothelial Keratoplasty (DMEK), uses a much thinner layer of donor tissue.

This procedure removes diseased tissue from the front corneal layers, namely epithelium and the stroma, but leaves the back endothelial layer in place. This is suitable for patients who are having corneal problems involving only the front portion of the cornea like a superficial scar. Depending upon the thickness and depth of the tissue removed, the procedure can be Superficial Anterior Lamellar Keratoplasty (SALK) or Deep Anterior Lamellar Keratoplasty (DALK). The removed tissue is replaced with the corresponding layers of donor cornea and secured in place with fine sutures. The back layers of the cornea are not disturbed and left intact.

There are a number of corneal conditions which cannot be treated with medication alone. The following is the list of conditions that may benefit from corneal transplantation to improve vision.

• Cornea scarring, caused by injury or infection
• Keratoconus - A condition in which the cornea gradually bulges out
• Clouding of the cornea
• Thinning of the cornea
• Swelling of the cornea
• Corneal ulcers not responding to medical treatment
• Complications caused by previous eye surgery

Cornea transplant is a relatively safe procedure. Still, it does carry a small risk of serious complications, such as:

• • Eye infection following surgery as with any other intra ocular surgical procedures.
• • Increased risk of cataract in some patients
• • Pressure increase within the eyeball called Glaucoma
• • Problems with the stitches used to secure the donor cornea. In endothelial keratoplasty there are no sutures used to secure the donor cornea unlike in PKP or DALK
• • Rejection of the donor corneal graft can happen even years after the transplant surgery

A complete pre op evaluation of both eyes is mandatory including visual acuity assessment, intra ocular pressure and examination under dilation to check the nerve fibre layer called retina and status of optic nerve. The risk factors are noted down and the consultant will discuss in detail about the surgical procedure, what to expect after the surgery, the post operative medications, frequency of follow up visits etc. Patients are advised to get one of the family members during the discussion to clarify any doubts regarding the surgical procedure. All the surgeries are done under local anaesthesia except in children where general anaesthesia is preferred. After baseline blood examination and assessment by the Anaesthesiologist, the patient is booked for the transplant procedure.

The blood vessels of the retina leak and results in bleeding into the retinal layers and fluid collection. In its early stages diabetic eye disease often has no symptoms. When it involves the sensitive central part of the retina, called macula, visual symptoms develop.

A dilated eye examination allows your Ophthalmologist to examine more thoroughly the retina and optic nerve for signs of damage before you notice any change to your vision.In the early stages the visual impairment may be mild but as the disease advances with more and more bleeding and swelling of the retina, it can lead to complications like intra ocular haemorrhage into vitreous cavity, retinal detachment and even permeant loss of vision.

Proliferative diabetic retinopathy is an advanced stage of the disease wherein inadequate oxygen supply to the retina results in the growth of abnormal blood vessels which bleed easily due to their fragile nature. This adds to the burden of already damaged retina and worsen the condition.

Modern screening methods will alert us to diabetic eye disease before the onset of symptoms. The decision to treat is made on the basis of clinical examination and special tests, including fluorescein angiography and OCT retinal scanning

Maculopathy, threatening the centre of vision is treated with laser burns, which 'dry up' the waterlogged retina. Injections into the eye may also be helpful. Proliferative diabetic retinopathy is treated by the application of laser burns to the periphery of the retina. This reduces the volume of sick retina, whilst saving blood supply for the important central macular area. Bleeding into the vitreous of the eye may require vitrectomy, a surgical procedure in which the blood-stained gel is safely removed. Bleeding points are treated and laser applied to prevent the development of more abnormal 'new vessels'. Modern vitrectomy surgery has revolutionised the treatment of severe proliferative diabetic retinopathy, giving hope to the most desperate of cases.

Slow and often unnoticed decrease of vision and reduced field of vision Headaches accompanied by redness and pain in the eyes Frequent change in glass prescription Reduced vision in low light conditions or at night Seeing coloured haloes or rings around light bulbs

Primary open-angle glaucoma
It is the most common form of glaucoma where the eye’s natural drainage canals become clogged over time. This is dangerous, because most people have no symptoms or early warning signs. If it is not diagnosed and treated, it can cause a gradual loss of vision.
Open-angle glaucoma treatment
After proper investigations and confirmation of diagnosis, eye drops are used to lower the eye pressure. There are various kinds of eye drops and the doctor will choose the best drop for you depending on associated conditions such as asthma, diabetes, inflammation in the eye etc
Angle-closure glaucoma
It is a type of glaucoma in which the drainage area or angle is closed or narrow. Consequently fluid inside the eyes (aqueous humour) cannot drain out normally which leads to a rise in eye pressure. This may lead to pain in the eye, redness, decreased vision and coloured halos around light. Angle-closure glaucoma may have acute symptoms and need immediate attention in the form of medicines and laser to relieve the acute attack.
Angle closure glaucoma treatment
In addition to drops and tablets, a laser may be recommended to create an alternative opening to relieve the angle closure and allow fluid to pass through and open the blockade (YAG PI). Patients who do not respond to lasers and medicine will need surgery
Secondary glaucoma
Secondary glaucoma develops as a result of other eye conditions such as trauma or injury or complicated surgery, inflammation, use of certain drugs like steroids, etc. Sometimes it may be due to pigment release from the eye (pigmentary glaucoma) or due to deposition of flaky material (pseudo-exfoliative glaucoma). The treatment depends on the cause of glaucoma.
Normal Tension Glaucoma
Also known as low-tension glaucoma or normal pressure glaucoma. In this type, the optic nerve is damaged, despite the pressure remaining normal. Those at high risk for this form include patients with a family history of glaucoma, history of systemic heart diseases, especially rhythm abnormalities.

A complete eye examination is needed to diagnose glaucoma. In addition to vision and routine slit lamp examination, eye pressure estimation (Tonometry) followed by evaluation of the drainage angle using a special type of lens (Gonioscopy) is done to know whether a person is having open or closed angle glaucoma. A dilated retinal examination of the retina is important to rule out damage to the nerve. Some of the other tests include visual field testing and scanning of the nerve with the help of specialised equipment (OCT).

Glaucoma can be treated both medically and surgically.
A number of eyedrops are available that help to reduce the intra ocular pressure. Surgical treatment includes both filtration procedures as well as LASER.

• • People over the age of 40
• • Family history of glaucoma
• • Long time steroid users
• • History of injury to the eye or previous eye surgery
• • Patients with high power glasses (plus or minus)
• • Diabetes and hypertension

People at high risk of glaucoma should get a complete eye exam, including dilated eye examination , once every year. Tests include tonometry, gonioscopy, and in people suspected of having glaucoma, visual field tests to detect glaucoma at an early stage.

Some of the treatable causes of childhood blindness include

Uncorrected refractive errors and squint
Cataract
Glaucoma
Corneal ulcer and scaring
Retinopathy of prematurity-occurs in pre mature babies

Vision can be tested grossly as early as 6 months after birth and if the baby is suspected of having poor vision in one to both eyes, requires further evaluation to diagnose the cause of poor vision.

Between 3-4 years, vision van be assessed using pediatric symbols (LEA symbols/ HOTV chart).

Four to five year old children can be tested using standard optotypes.

Children should continue to have annual vision examination throughout the childhood and adolescence

Poor vision for distant objects caused by refractive errors are the most common cause of visual impairment in children and often goes unnoticed by the parents. Symptoms of poor vision include squeezing eyes while watching TV or blackboard, holding things closely to see clearly, poor school performance, frequent complaints of headache and eye strain.

Deviation of eyes in which the eyes look in different directions instead of looking straight (Squint)

Watering with or without redness in one or both eyes

Drooping of eyelid( Ptosis)

Congenital cataract may be seen as a white reflex in the pupillary area and sometimes oscillating eye movements (Nystagmus)

Congenital glaucoma often presents with the child having watering of eyes, intolerance to light and large cornea