I was quite happy at the interest shown by all who have volunteered to work with us to tackle the increasing scourge of blindness. Volunteers had come together for a workshop to learn how to screen for eye diseases or visual impairment in members of the public.
I had the arduous task of teaching them how to go about it in just three hours. Starting with how to measure visual acuity, I could see that many faces drew blank after about 30 minutes. I was helped by the inquisitiveness of some of the members who asked searching questions.
The first salvo was thrown by Dele, who asked, “My eyes are normal and I see everything clearly? Are my eyes truly normal?” Funny question but loaded! “I can’t answer that question now,” I replied. “At the right time, the answer will become very clear to you,” I said with an air of certainty. It was Lanre’s turn to ask the next question. “Sir, you’ve been talking to us about Visual Acuity. What is Visual Acuity?’ I was taken aback.
It was the first thing I talked about at the beginning of the interaction. Perhaps, I had not been explicit enough. Slowly, stressing every word, I went over it, “Visual acuity is the clarity or sharpness of vision – a measure of the ability to distinguish letters and numbers at a given distance, usually 20metres or six feet.” It describes how well you see detail with your central vision.
Thus, if you are told that you have a 20/20 (6/6) vision, it means you are capable of seeing at 20metres (6ft) what a normal eye can see clearly at 20metres (6ft). If your vision is 20/100, it means you see at 20metres what a normal eye can see at 100metres. That isn’t good. Is it? It means if you and Lanre are both standing 100metres away from an object, to see and appreciate what he is seeing, you have to move closer until you are 20metres from the object before you can see it.
What this means is that you have an impairment of vision. This impairment can be due to a problem in the eye such as cataract, an optical problem requiring correction with glasses or some other problem in the body such as diabetes or in the brain.
“How would you differentiate between a vision problem caused by a disease process and that caused by an optical problem?” asked Femi. Femi had a pair of glasses with thick lenses. “Please, remove your glasses,” I commanded. He obeyed. “Would you mind reading out loud the numbers on the number plate of that car opposite us,” I asked.
Femi couldn’t see them while everyone, including those standing far behind him, could. I punctured a piece of thick cardboard with an office pin and handed it over to him. “Femi, please, put it in front of your right eye. He obeyed. “Now shut your left eye while peeping through the hole in the cardboard with your right eye,” he did as directed. “What do you see through the pinhole?,” I asked.
“POP 123AB,” he read out correctly. Everyone cheered. The pinhole confirms that Femi has an optical problem and that glasses would help him see better. That is exactly what his glasses have been doing for him. It does not however rule out the presence of a disease. Even in the presence of a normal vision, there can still be a serious eye problem such as glaucoma.
In a nutshell, a vision of 20/20 (6/6) with or without a pinhole or glasses does not mean the eye is normal eye. I looked at Dele and smiled. He smiled back and said, “You have answered my question.”
I was pleased that I was making some sense. I quickly seized the opportunity to hold on to their attention further by anticipating the next question and providing an answer before being asked. “There are at least, two other examinations that must be performed before you can say an eye is functionally normal. These are, Visual Fields and Colour Vision.
A visual field test is an eye examination that can detect an abnormality or impairment of function in central and peripheral vision. This may be caused by various medical conditions such as glaucoma or a lesion in the brain.”
I stretched it further causing a bit of confusion, “Kindly note that even the visual acuity, visual fields and colour vision may be normal in the presence of structural abnormality in the eye.” Thus, a physical examination is mandatory.
“What is VISION 2020 (Twenty-Twenty)?” asked Mr. Johnson, a retired school principal. This is the year 2018. Next year is 2019 and thereafter comes the great year 2020. VISION 2020 is a global initiative that aims at eliminating avoidable blindness by the year 2020. Launched on 18 February 1999, by the World Health Organisation (WHO), it is a partnership that provides guidance, technical and resource support to countries that have formally adopted its agenda. Is it possible for us to eliminate blindness in Nigeria by the year 2020? 2020 is just two years away.
Seemingly impossible, what is possible is to give everyone in Nigeria the RIGHT TO SIGHT. Even that is a tall task. There is something, however, simpler for you and I to accomplish. “What is it?” asked Femi. “Go for an eye examination today and once every year to prevent your name being added to the statistics of the blind,” I advised.