WHAT IS EYE POWER ?
How can I stop my eye power from increasing? What can I make my child eat to reduce eyesight power? How to decrease or reduce eyesight number ? or How to reduce eye number? are some of the most common questions we eye doctors get asked at our hospitals.
Eye number means your child has to wear glasses or contact lenses. In technical terms, it means your child has a refractive error. Someone having a refractive error basically means they have to wear glasses or contact lenses. Vision means how much someone can see with or without glasses. You can improve your vision by wearing glasses and ofcourse this vision decreases if you take them out.
The glasses or contact lenses number/eye power or more correctly the lenses in the spectacle frame can have three types of numbers.
These are :
- Myopia – A-minus numbered lens or minus eye power
- Hyperopia – A plus numbered lens or plus power eye
- Astigmatism – A plus power eye or minus power eye with an added axis to that number.
WHAT DO THESE DIFFERENT EYESIGHT NUMBERS MEAN?
Let’s look at each of the types of eyesight numbers that one can have in their lenses. In other words, lets try and understand what is eye power. Many must have heard the terms nearsightedness or farsightedness. Lets understand what these mean.
Myopia is also called Nearsightedness. This is the most common eye power. Refractive error is a more technical name for eyesight power.
People with nearsightedness will have difficulty reading road signs and seeing distant objects. You will yet be able to see well for close-up tasks such as reading, mobile phone usage, and computer use.
Here the lenses have a minus number and Myopia occurs because the eyeball is longer than normal.
If an eye doctor were to write this glasses number on a prescription it would look like -0.50DS or -0.75DS or -1.25DS. We wouldn’t write it as -0.50 power of eye or eyesight number. Here DS stands for diopter sphere. DS is the measurement of eye power.
This is also known as farsightedness. Some amount of Farsightedness is normal in younger children. Here the lens is of a plus number. Plus sight means that the eye is slightly shorter than normal. Inspite of having plus power eye children can see things. They may be seeing these things blurred but they can still see things. Thus, in children, this often goes unnoticed. Some children born with farsightedness have never seen close objects well. In fact they may not be aware that it’s possible to see them better. Also, hyperopic children can sometimes see close objects well by straining their eyes. Thus plus sight means they may complain of headaches, but not blurring. These headaches occur due to them focussing hard to see things clearly.
If an eye doctor were to write this glasses number on a prescription it would look like +0.50DS or +0.75DS or +1.25DS. We wouldn’t write it as +0.50 power of eye or eyesight number.
Astigmatism: difficulty focusing objects at all distances
If you have astigmatism, you will have blurred vision at all distances. One may also complain of eyestrain and headaches. Children also tend so squeeze or ‘squint’ their eyes to see better when they have astigmatism. An Astigmatism prescription could contain both plus and minus numbers but along with the numbers they have an axis written next to it. These eye numbers are also known as cylindrical numbers.
If an eye doctor were to write this glasses number on a prescription it would look like -0.50DC*180 degrees or -0.75DC*90 degrees or -1.25Dc*110 degrees. We wouldn’t write it as -0.50DC*180 power of eye or eyesight power. Here DC stands for diopter cylinder.
There is something important you should know. These powers are usually seen in both eyes. Most of the times these eye powers are somewhat similar in both the eyes. Sometimes, these numbers can be very different in each eye. Lets say the left eye has a number of -4.0 Dipoter and right eye has a number of -0.50 Diopter. In this situation the person would be able to clearly see with the right eye and may not notice poor vision in the left eye. When the eye powers are different in each eye it is known as anisometropia. It is important that anisometropia is ruled out in children for the sake of their vision and eye health.
CAN THE eye power INCREASE ?
Your child’s glasses number can change. Yes, usually the eye power can increase. But it’s not that simple.
Myopia or minus eye power can increase with age.
Hyperopia or plus eye power does not increase and in fact, can reduce a bit up to 6-7 years of age.
Astigmatism usually remains the same and does not increase or decrease.
HOW DOES THE EYE POWER INCREASE ?
As mentioned the power of the eye can increase. The actual reason why power increases is an increase in the length of the eyeball. If the eye grows longer then the glasses number increases.
Below are the reasons why the power of the eye increases.
why does power of an eye increase ?
As mentioned earlier ‘ How to reduce eye power‘ or ‘How to improve eye number ?’ are some of the most common questions we get asked. Reducing the eye power or imprving the eye number is not something we can control. This increase or decrease actually happens on its own. Of course, new research says that eye power increase can happen due to the following reasons.
The first reason is genetics. If the parents have a high minus number then the chances of the child having a high minus number increase. It is not much you can do about this.
The second factor is the amount of near work. The use of Ipads and phones falls within this category. If your child is spending too much time doing these activities then myopia may increase.
The third factor is the amount of outdoor activity. When we do any sort of outdoor activity we are looking at distant things. This reduces the chances of eye power increasing.
Thus if one wants to improve the eye number or prevent the power of the eye from increasing, then they have to reduce their iPad use. They also have to increase outdoor play. These two steps will help to protect your eyes from an increasing refractive error.
how to reduce eye number ?
Is it possible to reduce eye power ? Well, there is no real way of reducing the eye number. One can however get rid of their glasses by undergoing a Lasik eye surgery.
You can however take steps to derease the chances of increase in eye power. These steps will not improve the eye number or decrease eye power. They will only prevent an increase in eye power.
ATROPINE EYE DROPS
These are types of contact lenses and one wears these while sleeping. These lenses change the shape of the cornea while we are sleeping. This change is temporary. Now, because of this change when one gets up and removes the contact lens they can see without glasses. This clear vision would last until the evening. If one wants to remain glass-free they would have to wear these contact lenses every night. Not many eye doctors use this form of treatment but it is still available. This is available at Eye Solutions and one can read about Orthokeratology.
These glasses are usually worn by individuals over 40 years of age. In children, they tend to reduce the eye strain when seeing near objects. This reduction in strain decreases the chances of Myopia progression. Now, it’s important to keep in mind that this is a theory and even though literature does have reports supporting this, these reports are not many.
Blue Light blocking lenses
Because of the pandemic we all got onto the computer for many more hours in the day. There has been a lot of dicsussion about these blue light blocking or blue filter glasses. These lenses actually provide no additional benefit. You can read more about blue light blocking glasses.
Do eye exercises help to reduce eyesight power ?
There are many who claim that eye exercises can help in reducing eyesight power. Sometimes these eye exercises are referred to as eye yoga. Some even tell you not to wear glasses because they can be addictive. There is however no evidence to suggest that eye exercises can reduce eyesight power. We also know that these exercises do not harm your eyes in any way. So, what we tell our patients is, that if they want to try out eye exercises or eye yoga to improve your eyesight then they can go ahead. However, they should not stop wearing their glasses as sometimes it can significantly affect eye health and lead to something known as Amblyopia.
HOW DO I KNOW IF MY CHILD HAS EYESIGHT POWER?
You may think that your child does not have a vision problem. Your toddler may not be old enough to read the eye chart, but that shouldn’t stop you from getting his eyes checked. This is where a routine eye check-up becomes important. It’s important to get your child a baseline eye evaluation from an eye specialist for children early in life. We recommend an eye exam as early as two months. This is especially true if you have a family history of eye problems or notice anything unusual (like any of the symptoms below). Since he’s too young to know when something’s wrong with his eyesight or know that he has an eye problem, you have to look for the following symptoms.
- Sitting close to the TV while watching
- Eyes look crossed or don’t move in unison.
- A complaint of headache – the child may tell you his head hurts; other signs include holding his head, and not liking bright lights or loud noises).
- Squints or cocks his head to one side when he gazes at something
- Shows signs of dizziness (he seems off balance or complains that he sees spots).
- Bumps into objects that other kids skillfully avert.
- Frequent rubbing or blinking of eyes
- Holding objects or books unusually close or far away
- Squeezing eyes to see
If your child has any of those symptoms, you should be taking your child to a pediatric ophthalmologist or an eye doctor for a routine eye check-up.
WHEN CAN I TEST THE EYESIGHT POWER FOR MY CHILD?
EYE TESTING FOR INFANTS
Babies are able to see as good as adults as regards focusing ability, color vision, and depth perception by 6 months to 2 years of age. To assess whether your baby’s eyes are developing normally, your eye doctor will use the following tests :
“Fixate and follow” testing determines whether your baby’s eyes are able to fixate on and follow an object. The object could be a handheld toy as it moves. Infants should be able to fixate on an object soon after birth and follow an object by the time they are 3 months old.
EYE TESTING FOR PRESCHOOL CHILDREN
Parents find it interesting that preschool children do not need to know how to read to undergo eye tests. This is actually true even when they are too young or too shy to verbalize.
SOME COMMON EYE TESTS USED FOR YOUNG CHILDREN INCLUDE:
Lotus symbol chart for young children is like regular adult charts with letters. Except that they have special symbols instead of letters. These symbols include a kite, house, bell, bird, and star.
Retinoscopy: This is a test that involves shining a light into the eye to look for the reflection from the back of the eye (retina). This test helps eye doctors determine your child’s eyeglass prescription or eye power.
Dilated retinoscopy: in this test after putting eye drops in the child’s eye, a confirmed eyesight number is obtained. This is to get the correct and precise spectacle numbers. Dilation usually takes around 20 minutes. Once we dilate to check the eye number your eye doctor will also examine the retina and the optic nerve.
How to remove eye number ?
Most of you want to improve your eyesight. Lasik is a very popular procedure amongst those who don’t like to wear glasses and want vision correction. Please read more about LASIK. Lasik helps in getting rid of glasses. Usually, LASIK is done after 19-20 years of age.
Frequently Asked Questions
Your child require glasses or has an eyesight power because the length of eyeball is shorter or longer than what is considered normal.
Having glasses does not mean that the eye is weak. Neither does it mean that the parents or children have done something teribly wrong to get this power.
Myopia can increase with age. Hyperopia and astigmatism usually dont.
No. Your children’s eye specialist will prescribe glasses to your child so that he or she can see clearly. In younger years glasses are also prescribed so that vision development proceeds normally. Glasses are not prescribed so that the number reduces or wearing glasses will not reduce the eye number.
Usually yes. Sometimes children with myopia dont wear glasses when doing near work and that is fine. As mentioned in the article above there is a theory that not wearing glasses for near may actually reduce the chances of eye power increasing.
However, there is not harm either in wearing the glasses all the time. Hyperopes and children with astigmatism should wear glasses all the time.