Knowledge Centre

  • Glaucoma
  • Retinopathy of Prematurity (ROP)
  • Cataract
  • Squint (strabismus)

"Glaucoma ...should be taken seriously... Because..Sunrise can’t be heard..."


Patient: Dr. you have mentioned that I am suffering from Glaucoma. What exactly is Glaucoma?

Eye Specialist: Whenever the sensitivity of the retina diminishes, as we call it 'Optic Neuropathy', the patient inches towards blindness, gradually. It shortens the 'visual field' from the counters of vision, leading to gradual and permanent blindness. The loss of vision is irreversible and permanent.

Patient: Dr. What are the risks factors for Glaucoma?

Eye Specialist: The following table shows various risk factors for Glaucoma

Strong Risk Factors

  • High eye pressure
  • Family history of glaucoma
  • Age 40 and older
  • Age 60 and older for the general population, especially Mexican Americans
  • Abnormal optic nerve anatomy

Potential Risk Factors

  • High myopia (very severe nearsightedness)
  • Diabetes
  • Eye surgery or injury

Unfortunately, most patients realize it late, when Glaucoma has already progressed more than 40%. To avoid the same, timely diagnosis and immediate treatment is necessary to check the progression of Glaucoma.

Patient: I understand the seriousness of the disease. However Dr, I haven’t experienced any symptoms nor am I having any problem in my vision. Then, why do you say that I am suffering from a serious from a serious condition like Glaucoma?

Eye Specialist: Glaucoma is a 'silent killer' of vision. Most of the patients do not experience any problems initially, and hence the patients don’t take the condition very seriously. Glaucoma gradually keeps pushing a patient towards absolute blindness. It is like a termite that eats away the vision gradually. Therefore, all our efforts are aimed to preserve your existing vision, as nothing can be done for the vision you have already lost. Thanks to the modern diagnostic methods like Visual Field Test and Gonioscopy facilitates early diagnosis. Taking your prescribed eye drops and other medications regularly prevents the patient from becoming blind. It is those patients who are ignorant or negligent about Glaucoma and the medication, who are likely to be a victim of blindness.

Q: What is Retinopathy of Prematurity?

A: Retinopathy of Prematurity shortly called ROP is a proliferative retinopathy affecting premature infants of very low birth weight who have been exposed to high oxygen concentrations. The retina is unique among tissues in that it has no blood vessels until the fourth month of gestation at which time the vessels emanating at the optic disc grow towards the Periphery. These vessels reach the nasal Periphery after 8 months of gestation but do not reach the temporal Periphery until about 1 month after delivery. This incompletely vascularized retina is particularly susceptible to oxygen damage in the premature infant.

Q: Which babies should be screened for ROP?

A: Babies born at or before 31 weeks gestational age or weighing, 1500 grams or less should be screened for ROP they should be screened by an ophthalmologist with experience in ROP screening. The screening should begin 4 weeks postnatal age to detect the onset of disease.

Review of these babies should be done on a weekly basis or once in two weeks intervals depending on the severity until the retinal vascularization reaches zone 3.

The pupils are dilated with dilating drops and the ROP screening must be done by an ophthalmologist who is an expert and who has been trained specifically for this and who can handle such small babies.

Q: Which babies would require laser?

A: Not all babies who are screened for ROP would require laser only the babies who have threshold disease would require laser photocoagulation of the immature retina for this purpose the babies who are called for screening are advised to come very regularly without missing appointments so the threshold disease is not missed.

What is cataract?

Cataract is a medical condition in which the lens of the eye becomes progressively opaque, resulting in blurred vision.

The crystalline lens of the eye is enclosed behind the pupil (the coloured part), inside a transparent lining called "the lens capsule".

It is not important how serious the clouding of the eye is, nor if it affects all the lens or just a part of it.

Cataract treatment is always the same and it is advisable to remove the opaque lens and replace it with an artificial one.

Is cataract surgery serious?

All surgery involves some risk, so yes, it is serious. However, cataract surgery is the most commonly performed type of surgery in the United States. Many cataract surgeons have several thousand procedures under their belt. Choosing a surgeon with this much experience will reduce the risk of something going wrong.

How is a cataract removed?

A small incision is made in the front surface of the eye with a scalpel or a laser. A circular hole is then cut in the front of the thin membrane (anterior capsule) that encloses the eye's natural lens. Typically the lens is then broken into smaller pieces with a laser or an ultrasonic device so it can be more easily removed from the eye.

Once the entire lens is removed, it is replaced with a clear implant called an intraocular lens (IOL) to restore vision. In most cases, the eye heals quickly after surgery without stitches. Today, several steps in cataract surgery can be performed with a computer-controlled laser instead of hand-held instruments.

What is strabismus?

Strabismus is the medical term of a squint, a condition where the eyes point in different directions. One eye may turn inwards, outwards, upwards or downwards while the other eye looks forward.

Squints are common and affect about one in 20 children. They usually develop before a child is five years old, but can appear later, and adults can also be treated for the condition.

How squints affect vision?

The most obvious sign of a squint is eyes that look in different directions. Squints can also cause: double vision; lazy eye(amblyopia) in young children where the vision is poor in the eye with the squint; and a squint can cause people to develop an abnormal position of the head.

If a squint is left untreated in young children, lazy eye (amblyopia) can develop. The vision in the affected eye gradually deteriorates because the brain ignores the weaker message being sent from that eye. A lazy eye can be treated up until about six or seven years of age, but it is important that it is treated as soon as possible.

Types of squint and what causes them

Most often, one eye turns inwards (convergent squint) or outwards (divergent squint). Less often, it may turn up or down (vertical squint). There are different terms for how often the squint is present. If they are there at all times they are termed constant, or if they are only apparent at certain times they are know as intermittent.

Some babies are born with a squint (known as a congenital or infantile squint) and some children develop a squint later (known as a acquired squint). Acquired squints may be caused by the eye attempting to overcome a vision problem, such as short sightedness or long sightedness and genetic factors play a part in many squints, but in many cases the cause is unknown. Rarely, a squint may be caused by a condition in the eye itself.

Treatments for squints

Most squints in children need to be assessed as soon as possible to ensure the vision is protected and to improve the chances of successful treatment.

Treatments include glasses and, occasionally, eye exercises. If your child has a lazy eye, they may need to wear an eye patch to improve the vision in the affected eye. Many patients may only need the condition monitoring reqularly.

In some cases, corrective surgery may be undertaken, most commonly to improve the appearance of the eyes, but sometimes to correct double vision or, in young children, to try and develop the co-ordination of the two eyes to work together for 3-D (depth) vision. Occasionally, surgery is done to improve an abnormal position of the head.

Squint surgery is a very common eye operation. It usually involves tightening or moving one or more of the outside eye muscles which move the eye to change the eye position. These muscles are attached quite close to the front of the eye under the conjunctiva, the clear surface layer. The eye is never taken out of the socket during surgery. Stitches are used to attach the muscles in their new positions.

Squint surgery is nearly always a day-case procedure, so you should be in and out of hospital on the same day. There are two kinds of squint operation - adjustable and non-adjustable. In adjustable surgery, which can be performed in older children and adults, the stitches can be adjusted shortly after the surgery, when the patient is awake.

Risks from surgery are rare, but there can be unpredictability in the exact postion of the eyes after surgery and sometimes more than one operation will be needed.

Occasionally, squints corrected during childhood reappear in adulthood. You should visit your GP as soon as possible if you develop a new squint.

Recovering from surgery

It can take several weeks to fully recover from corrective squint surgery.

During this time, the eye may feel painful or itchy for a short time and you may have temporary double vision.