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Understanding Eye Power: Myopia, Hyperopia, Astigmatism, and Beyond

Category : 
Author : Dr Deepak Garg
Amblyopia / Astigmatism

We understand that vision health is of utmost importance to everyone, and we are here to provide you with the answers you seek. This guide will address the common eye power-related questions that we frequently receive.

1. What Does Having Eye Power Mean?

Having eye power means your eyes have a shape such that the rays of light do not focus on the back part of the eye called the retina. Thus, to make them focus on the retina, you need specific lenses in front of your eyes, either spectacles or contact lenses. The power of the eye is denoted by the power of the lens used to make you see clearly. The power of the eye can be of three types: Plus number or hyperopia, minus number or myopia, and cylindrical number or astigmatism.

2. What Does Negative Eye Power Mean?

Negative eye power means you need a negative lens or a minus-powered lens to make the rays of light focus on the retina. In other words, a minus-numbered lens will help you see clearly. This type of power is found in individuals complaining of having blurry distance vision. The medical term for negative eye power is Myopia, and it has become a topic of interest in recent years because it is expected that half the world’s population will have negative eye numbers by 2050. This is the most common type of eye power seen in the population. The eye number can progress, and there are certain tools available to help reduce the risk of this progression. It is also a common reason why people undergo Lasik eye surgery or Clear lens extraction.

3. What Does Positive Eye Power Mean?

Like negative eye power, positive eye power means you need a positive or plus-powered lens to focus the rays of light on the retina. This type of power is found in individuals complaining of blurry near vision. The medical term for positive eye power is Hypermetropia. Although it is not considered as big a concern as negative power, if undetected at a young age, it may cause a condition known as lazy eye or amblyopia. All humans are born with around +2.00 numbers, which is why eye doctors put certain drops in babies to determine their exact power and decide on the prescription that should be given, if needed.

4. What Does Cylindrical Power Mean?

Cylindrical power arises when the shape of the cornea, the frontmost layer of the eye, is like an oblate rugby ball shape, instead of being a regular spherical shape. This shape causes the power to be manifested only in a particular orientation called the axis. It does not mean that the eyes are weak or that there is a defect; it simply means the eyes have such a shape that the person needs a cylindrical number to see clearly. 

Abnormally high cylindrical numbers (>3.00) may indicate a condition called keratoconus, so the patients who have cylindrical eyesight of greater than 3 diopters undergo a test called topography once a year to make sure they have not developed keratoconus.

5. What Does Spherical Number in the Eye Mean?

Spherical power means the rays of light are not getting focused on the retina. They are either getting focused in front or at the back of the eye. Here, the shape of the cornea is regular, and the blur that the individual sees is a complete blur instead of the glare and shadowing effect seen in cylindrical power. Both Myopia and hyperopia are types of spherical powers.

6. What Does 6/6 Mean?

6/6 (read as 6 by 6) is a notation used in eye care to quantify your vision. “6” in the numerator stands for 6 meters, which is the testing distance, i.e., how far you are sitting when your eye test is being performed. The denominator denotes the ideal distance at which a person with no eye power must be able to see the line. Thus, ideal vision is 6/6 or 20/20. 20 refers to 20 feet, which is equal to 6 meters. It means that a person can see letters from a distance of 6 meters, which they are supposed to see from a distance of 6 meters. 6/9 means that a person can see letters from a distance of 6 meters, which they are actually supposed to see from a distance of 9 meters. 6/12 means that a person can see letters from a distance of 6 meters, which they are actually supposed to see from a distance of 12 meters, and so on. 

7. My Eye Doctor Prescribed Me Powered Glasses. What Does It Mean?

Depending on your eye power, your eye doctor will prescribe you to wear either negative or positive power glasses. The lenses in your spectacles or contact lenses will have the power to help you see better. You could have a spherical power or a cylindrical power. The spherical power could be a plus power or a minus power.

Some Common Specific Questions 

People ask us specific questions about their eye powers most of the time. One of these questions is, 

  • What does 0.25 eye power mean?
  • What does 0.5 eye power mean?
  • What does 0.50 eye power mean?
  • What does 0.75 eye power mean? 
  • What does 1.25 eye power mean? 
  • What does minus 2 eye power mean?

I will answer all together. 

When one has eye power, they can’t see clearly without glasses. The rays of light entering the eye are not focusing on the retina because either the eye is longer or shorter than normal. In other words, the shape is not the perfect shape that the eye should be.

To see clearly, we have to do something which will focus the rays of light on the retina, and we achieve this by giving lenses. Lenses could be in the form of spectacle lenses or contact lenses. 

0.25, 0.5, 0.75, and 1.25 are different eye powers, and it means that you have to wear lenses of these powers so that you see clearly. It does not mean that your eyes have a defect or are weak; it only means that the shape of the eye is slightly different than what it should ideally be. 

A person with an eye power of 5 or -5 has an eye that is much longer than somebody who has a power of -1 or -2. Similarly, a person having a power of -7 has an eye that is much longer than a person who has a power of -5.

PRO TIP: 0.25 and 0.50 are considered very small numbers, and there is a high chance that a person with such numbers would be able to see almost everything without glasses too. Not wearing glasses is not going to harm your eyes in any way, so if you prefer not to wear glasses for such small numbers, it is totally okay to do so.At Eye Solutions, we specialise in providing comprehensive eye care services, ranging from thorough eye examinations to advanced surgical procedures, in Mumbai & Chennai. In case you are facing any “Eye Conditions,” we urge you to schedule an appointment with our esteemed eye hospital in Mumbai & Chennai, where our top-notch team of eye specialists is ready to assist you.

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84 comments on “Understanding Eye Power: Myopia, Hyperopia, Astigmatism, and Beyond”

  1. So, what if when I stay indoors for long and come outside when is sunny and I can open my eyes well?
    When I force to open it, there will be tears coming out from my eyes.

    1. You are not expected to look at the sun. I think if anyone looks at the sun their eyes will water. If you do have excessive watering you might have dryness and maybe consult an ophthalmologist.

  2. Hello Doc, many years ago my eye doc prescribed me -0.25 and -0.50/75 power for glasses. But I didn’t wear any glasses until now. Currently the power has increased. On my right eye it’s -1.00 (15° axis) and on my left eye it’s -1.50 (165° axis). Should I constantly use glasses or the power will keep increasing if I don’t use glasses?

  3. I went for an eye clinic today and my results are as stated:

    CYL— OD -0.25 axis 180 degrees
    OS -0.50 axis 170 degrees

    They say I have astigmatism and that I need glasses for it. But when I searched for it in the Internet it says I have mild astigmatiosm and it does not need any glasses for it. But my mild astigmatism has symptoms, I keep experiencing headaches, nausea, anxiety and I feel like the ground is moving when I walk, eye ache at my eyelids esp when exposed to sun. Should I go with what they said or not wear glasses?? Oh and the SPH region says plano

  4. my SPH number for right eye is -1.25 and left eye is -0.75 and CYL number for both eyes is -3.25 axis 180. But, i am not able to see clearly through glasses object is getting distorted and blugy. what’s the issue?

  5. Hello Sir mera right And left eye ka number -1.55 he to sir ye vision jaise 6/6 hota he to ye -1.55 ka kitna _/_ hoga?

  6. I have minus 2.5 spherical and 1 cylinder number in right eye, minus 3 spherical and 0.75 cylinder number in left eye.

    Is it ok to wear only minus 3 spherical number in both eyes?

    1. Yes its ok. You may have headaches which may range from mild to severe. If you get headaches then you might have to wear the cylinder.

      but you are not benefitting in any way by wearing only -3. might as well wear your entire power.

  7. I realised I may need progressive lens recently. My current power is Right eye -5.75, Cyl -0.50, Add +0.50. Left eye -4.75, add +0.50. I have eye checkup at eye centre and optical shop.

    Eye centre’s new power is right -5.75, cyl -0.50, add + 1.75; left -4.50, add +1.75.

    Optical shop Right -6.25, cyl 0.00, add +1.75; left eye -4.50, cyl -0.25, add + 1.75.

    Can I check which power of progressive lens is better for eye and give better clarifty with lesser distortion? with astigmatism (eye centre) or without astigmatism (optical shop).

    1. Dear Amelia,
      You wont be able to check which eye power is better on your own.

      If you are based in mumbai we can do an eye check up and suggest which progressives you should get for your eye and your requirements.

      Regards

  8. hello doctor, my both eye sph no.is +0.50 and cyl is +2.75. right eye axis is 75 and left eye is 90. but I can see blurry through left eye. I checked up last week. is there any problem?

    1. WWhere did you get an eye check up ?

      Also i might not be able to tell you if there is a problem or not by these few lines. We will need to examine you in detail to comment.
      regards

  9. hello sir! I just recently got my eyes checked my soh for left and right eye is -3.75 and the cyl is -1.25 for both eyes so if I total both it becomes -5.0 (sph+cyl) I’m not sure about it can you let me know is it a high number or not ? and what can I do to reduce it without surgery

  10. Sir, I recently got my eyesight checked, and they recommended 0.50 glasses for me.Should I wear glasses or it’s okay if I don’t wear it.Is there a chance that my eyesight will completely recover if I don’t wore glasses?what I have to do to completely recover my eyesight..

  11. I am 29 years old. I checked my eyes from opthalmologist…he said that I have 1.5 and 1.75 cylindrical eye number in right and left eyes respectively. but I don’t feel any discomfort such as blurry vision etc. some time I feel like headache and eye strain when I watch more mobile i.e. more screen time. I am very tensed. is it very critical situation? can cylindrical numbers can be reduced or removed?

    1. Cylindrical numbers dont go away on their own. THey can however be removed by laser. the procedure is called Lasik

      as long as the cylindrical number is not increasing you dont need to worry.

  12. Hello sir.. I have keratoconus in my left eye and did c3r.. I have blurry vision in my left eye and I couldn’t see anything clearly with my left eye…But with my right eye I can see things properly. My Doctor suggested me to use contact lenses for my left eye and they said i have power 5… My question is will my vision improve if I use contact lenses?

    1. Dear Kaviya,

      these are special contact lenses known as scleral lenses. and yes there is a very high possibility that as soon as you try them on you will see much better.

      What you should do is come to Eye SOlutions for a trial which means you will get to know if contact lenses help you or not.

  13. my son has regressed rop at birth and now he is 2.5 years. we didn’t observe any eye issues with him during his regular activities but during his routine check up we come to know he has spect for both eyes with spherical +0.5 and cylindrical -2 with axis 140 so want to ask is it nearsighted/ farsighted or both (please explain his prescription) and whether it will reduced as he grows (As in blog it is mentioned all children born with +2)and 24*7 wearing of glasses essential

    1. He basically has a cylindrical power or what is also known as astigmatism. He will have to wear glasses most of the time. The number will not reduce and most likely will not increase either.

  14. hi
    my eye sight is -0.25 .my screen time is longer than usual .do you really suggest to year glasses

  15. Doctor, I have little power in both of my eyes (spherical 0.5), I have started wearing glasses, how do I get rid of the power permanently. I am only 18, and want to pursue sports (cricket), so it would be very nice to have no power, currently since 2 years I have 12 hours of screen time/day and it will be there for 1 more year then I can reduce, I have bought glasses with blue light filter. Please guide on how to get rid of power completely.

  16. I have a -0.25 CYL with – 7.5, but I don’t see any difference without the .25 cyl, can I get glasses only with spherical lenses?

  17. Meri eyes ke corner me redness rhti h pain ke sath, eyesight . 25 h, kya mujhe chasma lagana chahiye ya nahi

  18. Hello sir my daughter is 6yrs old her number of left eye sph +0.50 cylindrical -2.75 axics 172 and right eye sph +0.75 cylinderical -2.50 axics 174 . She is wear glasses 24hrs

  19. Hello sir my daughter is 6yrs old her number of left eye sph +0.50 cylindrical -2.75 axics 172 and right eye sph +0.75 cylinderical -2.50 axics 174 . She is wear glasses 24hrs any chance for removing glassesss

    1. Hi tarni, No, there is no chance of removing glasses. However, cylindrical number usually does not change so dont worry. You most likely will need once a year eye check up with your doctor.

  20. Hello Doctor,
    I went to eye clinic to verify my eyeglasses and they prescribes power as below for both sides
    Distant: Sph+0.5, Near Sph+1.75
    I have also complained about difficulties to adjust my present progressive glass while working/reading. Doctor suggested you can neglect your distance power if you are comfortable and choose only reading glasses and I am Ok with this.

    When I contacted glass makers for reading glasses, they said if you are making for near vision, number will be changed to +1.25 as power calculated earlier is combining both visions. Is this true? Shall I make +1.25 or +1.75 for reading glasses?

  21. I want to wear glasses and at the same time I want to protect my eyes so that it doesn’t affect my eyes, what glasses should I wear now, what power glasses should I wear to be safe when I go out, read a book at home, work on computer and go out in the sun, also for clear eyes also For the vision to be very clear

  22. Hi doctor, I’m 20 and my left eye is 16.5 and cyl is 5 and axis 95° right 13.5 and cyl 4 and Axis 95°, I feel tired easily and most of the time I stay home, and my vision is bad at night, i consult my doctor as I do every year and I told him I don’t see well at night but his reaction was like it’s ok like it’s normal, what should I do ?

  23. Hi dear respected doctor I’m from Bahrain I have -4 power I just want to know I can do laser surgery treatment or not ?
    Second is this available in India or not
    Or third question is in the beginning I was using power glasses for 2 years then I start power lenes -3.75 every 3 4 months I take new lenses I use lenses 6 years now I’m using glasses how many months or years I need to use glasses for laser treatment or eyes surgery please I’m waiting for your response thank you

  24. sir,I have cylindrical power -1.50 in right eye ,axis 10 and -1.25 in left eye,axis 160.sir can do eye exercises to improve my vision completely without using glasses again? sir, what is the reason for developing or increasing cylindrical eye power?

  25. I have a spherical power of minus 4.5 and cylindrical power of minus 4.5 ,
    what would be my myopic power of the eye
    will it come under high myopia category ?
    or under what grade of severity of myopia my eyesight comes under??

  26. Hi Doctor,
    We visit eye doctor yesterday to get my daughter’s eyes checked, she is 7 years old and premature just complete 8 month and got delivered and she was of 2 kg in weight. Eye doctor tested and told us that she has power of -1 in both eye as well as cylindrical power of -0.75 axis 170 left eye and -0.75 axis 10 right eye.

    1. Yes, it means she has a small power. THe number is not very high so dont worry and usually cylindrical numbers does not increase. I think you might have to get her glasses and see how her vision improves.

    1. Redcue screen time
      Spend more time outdoors
      Start Myopia control eye drops
      Wear speacial myopia control glasses

      Call 9820239958 if you want a detailed eye check up regarding your myopia.

  27. My son is 9 years old, we went for eye checkup, they told vision is good but have .5 power on both the eyes. What does this mean. and they referred to wear glass. whether we need to wear glass or not.

    1. If your child is complaining that he cannot see far things clearly then yes you will have to wear glasses. If child is not complaining then you can avoid for some time. Its a small number but the number can increase. Please read about myopia control and decide your next course of action.

  28. my head used to ache very badly since i have very high screen time of about 7 hrs everyday (except sunday). my doc recommended +0.25 power lens . he has said that i need not wear my glasses after a year , but one of my relatives said that she was told the same but its beem more than a year and she continues wearing specs .. will i face a similar situation after a year ? will my specs be with me life long?

  29. Hii Sir, I am a 25 year old female. I am using phone since I was 17 years old but my vision was completely fine with no strain. I got my eyes checked regularly and there was no power in my eyes.
    But the strain got increased at 22 and 23 years of age, both the time my doctor said that it’s ocular pressure and she gave me Lubricant eye drops and she said at 23 years of age it’s impossible to get eye Power.

    this year I turned 25, and for the past 15 days my strain got severe, I get it only when I use phone or laptop, so one-day I decided to check my vision, so I started reading alphabets from a distance. Then I realized my right eye is blurry. I went for the checkup and the doctor said that that I have -0.5cylindriçal,-0.25 sph in right eye(91 axis). And she has advised me to wear glasses.

    and she repeated the same dialogue that my power won’t increase.
    but she didn’t answer my question because last two times when I was 22 and 23 she said the same thing.

    doctor please help me, I am very scared

    1. Firstly nothing to be scared.
      Your number is very small
      Its ok if you dont wear glasses
      reduce your screen time, blink often, take a 20 second break every 20 minutes of computer work and look far away.
      Use lubricants like you have been asked to do.

  30. Right Eye:- SPH -0.75
    CYL -0.75
    AX 80

    Left Eye:- SPH -1.00
    CYL -0.75
    AX 90

    what is my eye sight 6/9 or 6/12 please suggest me

  31. Hi,
    I have high powers planning to do icl surgery.
    Is it possible to do icl surgery If powers are not stable or constant .

  32. my old spectacles power were -0.20and- 0.18 and now I have power -0. 05 is high or low? and does earlier one were high?

  33. hi sir, Is it ok for me to choose not to wear glasses with the powers 1.75 on the right eye and 2.25 on my left eye

  34. Hello sir!
    I just recently got my eyes checked bcz of strain in eyes and bit of headache and was told to wear Blue cut lens while using phones and other screens.
    Right eye
    Sph. +-
    Cyl. -0.50
    Axis 85
    vision 6/6

    Left Eye
    Sph. +-
    Cyl. -0.50
    Axis 75
    Vision 6/6

    Sir what this exactly means? What I need to do?

  35. Do we have 8/8 also just like we say 6/6 is a good eye vision. Do we have a name or anything for 8/8 eye vision.

  36. Prescription says +.25 sph in right eye and -.25 with axis 80 in left eye. Should I wear specs? Or will it becomes normal after sometime?

  37. Hello Sir, My son is 6 years old and he has +1 cylinder 80 axis in rigth eye while left eye is fine. Now after wearing glasses whenever he is looking down, he is feeling floor is tilted. Is this normal or have some other issues. Thanks !

  38. Hi doc, I have high cylindrical and spherical power in both eyes, recently my number changed within 1.5 year and I am feeling difference in my vision it feels like an object in front of my right eye which is not letting me see properly (crystal clear)

    previous power – OD -3.25 -2.75 x 040
    OS -2.25 -1.75 x 140

    new power – OD -3.00 -300 x 040
    OS -2.50 -2.75 x 140

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