The unnecessary war between structure and function

Today, I am taking a critical look at this little organ called the eye. It is undoubtedly one of the most important organs in the body. Without the eye one cannot see, but its absence or inability to function properly does not directly result in death unlike the brain, the heart and its tributaries, the liver, and the kidneys. However loss of function of the eyes, partial or total may have tremendous impact on the quality of life and by extension on the lifespan of a person.

The “product” of the harmony between the structure and the function of the eye is called “vision.” That is, vision is the ability of the eye to fulfil its role of providing sight. It is therefore obvious that for an eye to see, it is important to have and maintain a normal structure. The structure of the eye is often determined by events before conception of a baby or factors inherent in both the mother and the father of the child even before they come together – the genes.

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When mother and father come together, the mother’s egg or ovum unites with the father’s spermatozoa to form one cell. Thus the rudiment of a child is formed at conception. The single cell formed by the union is called embryo. It divides rapidly over and over again to give rise to the various organs in the body. A rapidly dividing embryo must have a favourable internal environment in addition to appropriate nutrients in quantity and quality to ensure well-coordinated and healthy growth and development.

The first three months of the baby in the mother’s womb (the first trimester) is the stage of formation of the structures or organs such as the brain, the eye and the heart. Therefore anything going wrong at this period (be it physical, infective or nutritional in quantity or quality) could result in serious structural abnormality and affecting the function after birth. Thus infections by organisms such as Rubella virus and Toxoplasma Gondi may result in severe abnormalities of the eyes and other organs.

The second three months (second trimester) is the stage of growth of these organs. Organs are not as vulnerable to insults as in the first trimester. The third trimester of pregnancy (last three months) is that of consolidation and the beginning of functional development and it is the least vulnerable. The function of the eye (sight) is not fully developed until several years after birth when there is interaction between the child and its environment. Therefore such factors such as infection, nutritional, sensory deprivation by covering the child’s eye for long periods may interfere with full development of the eye even after birth.

An ophthalmologist having trained for six years to become a medical doctor has acquired full knowledge of all these factors and knows their influence on the eye. He knows that any interference with its structure during pregnancy or after birth may cause visual problems.

By an additional four to six years specialised training, he acquires skills to treat eye diseases at all stages – from conception to birth. He understands that the eye is part of a larger body which is subject to influences and challenges from other parts. He is able to restore normal structure and function through the use of medications and if necessary surgery.

There is another cadre of eye care professionals called the Optometrists. For the eye to see very well there must be a balance within its structure, between its refractive surfaces and the sensitive film inside the eye on which the image is registered. By this is meant the relationships between the curvatures of the refractive surfaces of the eye – the corneas and the natural lens and the anterior-posterior diameter of the eye, called the axial length of the eye.

This is simply called the optical system of the eye. The work of the optometrist is to help to ensure this balance so that the rays of light being projected into the eye falls on the sensitive film inside the eye called the retina. They perform this task by taking measurements of the eye and providing glasses and optical appliances.  The name optometry consists of two words – “opto” (eye) “metry.” Thus it literarily means “eye measurements.”

The optometrist has no medical training. The “Doctor of Optometry” is a congenital anomaly because it is awarded to a first degree holder. It is not a specialist medical qualification. There is no need for a struggle between structure and function. The two professions complement each other.