Why eye examination?
The eye examination helps us to detect the conditions like glaucoma, hidden hyperopic correction, intermittent squint, Colour deficiency, retinal weakness (degenerations), muscle weakness (accommodative eye muscle problems), which are rarely noticed by people on their own, apart from usual spectacle corrections and treatment for other diseases of the eye.
What is an eye examination?
A complete eye exam starts with a detailed history of eye and general health problems, problems in other family members, and current medication history. The power of the spectacles being used is then checked and visual acuity is recorded with the correction being used – glasses or contact lenses. If the vision is found to be less than optimal refraction is performed and recorded to provide the optimal correction. The movements of the eye and the papillary reactions are then tested. A slit-lamp examination is performed to allow a study of the structures of the eye under adequate illumination and magnification, after which the intraocular pressure is measured. The pupils are then dilated to examine the retina and optic nerve in detail. All of these can be performed quickly and effectively by a well trained optometrist.
How long does an eye examination take?
This examination routine usually takes 10 to 15 minutes and dilatation of the pupils another 30 minutes. After dilatation, the ophthalmologist will complete the retinal evaluation and discuss the findings with you. The cause of problems if any and the requisite treatment measures are then discussed. The entire process should take an hour from start to finish.
When is an eye examination required?
Obviously, any change in vision or ocular comfort warrants an immediate eye exam, as does an injury to the eye. Other indications for an eye exam are abnormal head postures or squinting eyes in children, or a tendency to hold objects very close to the eyes. Even in asymptomatic children, a routine screening evaluation at the time of schooling can help detect conditions like a ‘lazy’ eye, small degrees of squint, color deficiency, and loss of 3-dimensional perception. In adults, a routine evaluation at the age of 40 years, allows the detection and correction of presbyopia, and monitors the intraocular pressure to ensure that glaucoma does not exist. Periodic eye exams after the age of 50 years at yearly intervals, or when systemic conditions like hypertension or diabetes are detected are necessary.
CORNEA & SCLERA
What is the function of the cornea and sclera?
The cornea and sclera form the protective shell for the delicate structures inside the eye. The sclera is opaque and tough, forms the back part of this shell and is covered by conjunctiva. The muscles that move the eye insert into the sclera. The cornea is the clear, transparent window in the front, transmits light into the eye, and with the lens, helps focus the rays on the retina.
What can go wrong with the cornea?
Infections – A variety of microbial agents can infect the exposed corneal surface, especially if there is injury. Contact lens use is a known risk factor for corneal infections. Unless treated promptly, severe vision loss can occur.
Injuries – Despite the protection of the lids, due to its exposed position, the cornea can be injured easily. This can result in corneal tears or if chemicals are involved, extensive burns of the entire ocular surface.
Inflammations – The cornea is affected in a number of conditions affecting the lids, conjunctiva, or other parts of the body. These can result in significant corneal inflammation and damage unless prompt, expert care is provided.
Genetic conditions – A variety of inherited diseases manifest at birth or in later life and can affect the size, shape or clarity of the cornea. Some of these may be a part of a wider syndrome with other eye and systemic changes.
Surgical damage – Although cataract surgery is a safe and effective procedure, it can sometimes produce corneal damage – especially in eyes with inherited corneal pathology. In these eyes, fluid collection in the cornea reduces sight.
Miscellaneous – Tumors can involve the cornea, and damage can result from improper contact lens fit and use. The cornea can be affected in dry eyes, improper lid closure, and if there is damage to the nerves supplying the eye.
What can go wrong with the sclera?
As with the cornea, the sclera can be involved in infections, injuries, inflammations, in some genetic conditions with extreme scleral thinning – resulting in a ‘blue’ appearance of the eye, and surgical damage.
How will I know if I have corneal or scleral diseases?
Since the primary function of the cornea is to provide clear sight, most conditions affecting this structure will result in altered visual function. However, small, peripheral changes may not initially affect vision, but may produce pain, irritation, redness or discharge. Many scleral conditions can result in severe pain in and around the eye. Persistent eye pain is often a sign of serious eye disease and should not be ignored.
What are the common causes of such diseases?
Injuries at work or play are important causes. If chemicals splash into the eye, often significant damage can result, unless prompt care is provided. Such injuries are often associated with infections as well. Many systemic diseases, especially those affecting connective tissues and joints, can have a corneal component, as can some medications used to treat these conditions. Surgical trauma and genetic conditions also are important causes of corneal disease.
How can these be treated?
Infections and inflammations of the cornea and sclera can often be treated medically in the early stages, although some surgical treatment may be needed if the condition is advanced. While very minor injuries can be carefully observed, most need to be treated. Similarly, early tumors can be treated with medications, while large extensions need surgery. Many of the conditions affecting the clarity of the cornea will need surgical therapy.
Recent advances in the management of these diseases?
Newer antibiotics help eradicate most of the infections in these structures. Chemical injury to the cornea can be effectively managed by limbal stem cell transplants, and in end-stage disease, by the use of an artificial cornea, keratoprosthesis. Corneal transplantation for scarring can now be done in a limited, lamellar manner, increasing the safety of the procedure. Similarly, for corneal fluid collection, a limited replacement of the posterior layers of the cornea dramatically improves the safety and outcomes of the procedure.
General information
If chemicals splash into the eye, it is important to promptly and thoroughly irrigate the eye with clean water. Especially in one-eyed people, the use of a shatterproof polycarbonate glass would reduce the risk of eye injuries.
Glaucoma
Glaucoma (high eye pressure) is a leading cause of blindness in the
elderly, by damaging the optic nerve. When damage to the optic nerve occurs,
blind areas develop in the field of vision, and usually go undetected until the
optic nerve is significantly damaged. The most common form has no symptoms in
its early stages. Glaucoma has therefore been nicknamed “the silent sight
thief”. Worldwide, it is the second leading cause of blindness. Glaucoma affects
one in two hundred people aged fifty and younger and one in ten over the age of
eighty. Early detection is the key to preventing this damage. A regular eye
pressure check is the best way to detect glaucoma.
Neuro-ophthalmology
Neuro-ophthalmology is a very specialized field of medicine incorporating
the fields of ophthalmology and neurology. About 25% of the brain’s neurons are
involved either directly or indirectly with vision. Many neurological conditions
(including life-threatening diseases like tumours and aneurysms of the brain)
often present first with eye symptoms. Many of the eye signs may be subtle and
missed if not recognized. Besides specific facilities for neuro-ophthalmic
evaluation,Our Clinic has access to excellent facilities for
Electrophysiological testing (like Visual Evoked Potentials) and neuroimaging
(CT Scan and MRI) and cross-referral facilities to expert neurologists and
neurosurgeons.
Squint and Child Eye Care
Any obstruction to vision at a young age can cause permanent damage to the
visual system that cannot be corrected later. Since small children often may not
notice such changes, it is very important that all children undergo a screening
eye exam at an early age.
Refractive errors, misalignment of the eyes (squint), structural problems,
retinal damage associated with premature births, and rarely a malignant tumor of
the retina – retinoblastoma, are some of the conditions that can affect vision
in children.
Retinal Health
The retina is a delicate, extremely complex light-sensitive “screen” that
lines the inner wall of the back of the eye. The vitreous is a jelly-like mass
that fills up the back of the eye and has shock absorbing and nutritional
functions. Retinal degenerations and holes that can lead to detachment of the
retina, damage due to diabetes mellitus and high blood pressure, and age-related
macular degeneration are some of the more common retinal conditions that can
damage sight.
ORTHOPTICS
Orthoptics, meaning “straight eyes,” is one of the medical sciences
specializing in eye care. Orthoptics is the study of the development of vision,
depth perception and the ability to use the eyes together, eye alignment, eye
movements, and eye coordination. The orthoptist’s particular area of expertise
is the evaluation and management of children and adults with “crossed” eyes,
“lazy” eye, double vision, and other eye coordination problems.
Orthoptic evaluation involves the measurement of the
muscle action according to the age requirements, including any deviation of the
eye
A SCAN
What is A Scan?
It is a method of measuring the axial length of the eye ball using
ultrasound. This test is done to measure the axial length of the eye ball (i.e.)
the distance from the front surface of the eye ball (cornea) to the back surface
of the eye ball (retina).
When it is recommended?
This test is done when there is any suspicion of reduced or increased eye
ball size like in myopia in one eye and hyperopia in other eye, small eye ball
since birth, protrusion of one eye and is always performed before cataract
surgery to calculate the power of the lens.
How is it performed?
It is done using a drop of local anesthetic, and the patient has to focus
at one point. It is a painless test and takes about 2 to 3 minutes. The ray of
light is allowed to pas through the eye from the front surface to the back
surface and it is measured in millimeters. The waves are projected on the touch
screen and the print out can also be taken.