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 !

Back-Projected Pixel Size: Back-projected pixel size (\(pix_{proj}\)) in a widefield or spinning disk confocal microscope (where an array sensor such as a CMOS or CCD camera is used) is the apparent size of a single camera pixel when back-projected into the specimen plane, which accounts for the effects of magnification. This value is simply found by dividing the real pixel size, \(pix_{real}\), by the total magnification of the system, \(M_{tot}\), as described in Equation 11.

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?

Figure 2. The relationship between axial resolution in a confocal microscope and pinhole diameter, normalized to the Rayleigh Criterion for resolution.

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.

Oldenbourg, R. and Shribak, M. Microscopes. In M. Bass (Ed.). Handbook of Optics, Volume 1: Geometrical and Physical Optics, Polarized Light, Components and Instruments (28.1-28.62). U.S.A.: McGraw Hill.

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.

\(\Delta z_{conf} = \begin{cases} \frac{1.5\eta\lambda_{ex}}{(NA_{obj})^2}\sqrt[3]{1+1.47AU^3}, & 0\le AU\le3 \end{cases}\) (21)

Depth of Field: Depth of Field (DoField) refers to the maximum Z distance from the most in-focus plane to the furthest plane that can be considered to still be in reasonable focus, and evaluated at the object plane. This is slightly different from 'Depth of Focus', where this distance is evaluated in the detector plane.

A number of methods have been described for calculating DoField. For this tool, we use the equation described by Young et al.\(^1\) and shown below (Equation 5). The authors provide a straightforward criterion: two points separated by a certain distance along the z axis can be considered to be in reasonable simultaneous focus if the spherical wavefronts emanating from these points have less than a quarter wavelength difference in position at the highest angle collected by the objective, evaluated when the middle of those wavefronts overlap at the entrance pupil of the objective lens.

We broadly classify additional system magnification not provided by the objective lens as either ‘camera relay’ (\(M_{relay}\)) or ‘system magnification’ (\(M_{system}\)). We make this distinction for multiple reasons, including in order to differentiate whether or not the magnification occurs in the light path between the pinhole disk of a spinning disk confocal microscope and the sample.

Figure 3. The relationship between optical sectioning in a confocal microscope and pinhole diameter, measured in Airy Units (AU). For this example, we are assumming an excitation wavelength \(\lambda_{ex}\) of 500 nm, \(\eta\) = 1.5 and NA = 1.49.

Axis eye meaning

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.

this number is very small. Its ok if you dont wear glasses. the number will not change but you will not have a problem if you dont wear glasses.

\(r_{lat-conf} = \begin{cases} \frac{C_{lat}\lambda_{ex}}{NA_{obj}}, & 0\le AU\le 1.2 \\ \frac{0.61\lambda_{ex}}{NA_{obj}}, & 1.2\lt AU \end{cases}\) (19)

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.

Yes it can happen initially and will take a week or so for him to get used to it. I dont think there is anything to worry.

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.

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

For the widefield case, it is equal to the widefield lateral resolution (\(r_{lat-WF}\)) divided by the back-projected pixel size (\(pix_{proj}\)) of the camera. For the spinning disk case, it is the confocal lateral resolution (\(r_{lat-conf}\)) divided by \(pix_{proj}\), since this technique also used a camera as a detector. For point-scanning, it is (\(r_{lat-conf}\)) divided by the virtual pixel size (\(pix_{virt}\)) since a single pixel detector is used and the illumination spot is scanned.

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.

A more recent review of the subject\(^5\) provides a detailed evaluation of both resolution and optical sectioning in a confocal microscope, including figures detailing the non-linear responses of lateral (XY) resolution, axial (Z) resolution, and optical sectioning to pinhole diameter.

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.

Please note that the confocal resolution equations described in this section are simple estimates for best-case imaging scenarios, and should not be interpreted as complete analytical solutions. In reality, confounding factors such as low signal-to-noise (especially with narrow pinholes) and optical aberrations limit the practical performance you can expect.

Brightness: The microscope objective determines the brightness of illumination, and rises with higher Numerical Aperture (NA) and falls with increasing magnification (\(M_{obj}\)). Note that the calculation for Brightness is different for transmitted (Equation 3) and reflected (Equation 4) light imaging as the former requires a seperate condenser for illumination.

Young, I.T. et al. Depth-of-Focus in Microscopy. SCIA’93, Proc. of the 8th Scandinavian Conference on Image Analysis, Tromso, Norway, 493-498 (1993). Lord Rayleigh, F.R.S. Investigations in Optics, with special reference to the Spectroscope. Phil. Mag. 8, 261 – 274 (1879). Oldenbourg, R. and Shribak, M. Microscopes. In M. Bass (Ed.). Handbook of Optics, Volume 1: Geometrical and Physical Optics, Polarized Light, Components and Instruments (28.1-28.62). U.S.A.: McGraw Hill. Wilson, T. Optical sectioning in confocal fluorescent microscopes. J. Micr. 154, 143 – 156 (1989). Wilson, T. Resolution and optical sectioning in the confocal microscope. J. Micr. 244, 113 – 121 (2011). Shannon, C. E. Communication in the Presence of Noise. Proceedings of the IRE, 37, 10–21 (1949).

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

Lord Rayleigh, F.R.S. Investigations in Optics, with special reference to the Spectroscope. Phil. Mag. 8, 261 – 274 (1879).

Numerical Aperture (NA): Numerical Aperture, usually abbreviated as 'NA', is how the resolution of a microscope is measured. NA is a dimension-less measure of the range of angles with which an optical component is able to accept or transmit light, and is described by Equation 2 below, where \(\eta\) is the refractive index of the immersion medium and \(\alpha\) is half the acceptance angle of the lens.

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.

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.

Back-Projected Pinhole Radius: Back-projected pinhole radius (BPPR) is the effective de-magnified size of the pinhole aperture(s) back-projected in the specimen plane, and is more specifically represented by the variables \(BPPR_{point}\) for point-scanning confocal and \(BPPR_{disk}\) for spinning disk confocal.

Your power has not increased because you did not wear glasses. Dont worry. You can choose to continue to not wearing glasses

The total system magnification, \(M_{tot}\), is found here by multiplying \(M_{obj}\), \(M_{relay}\), and \(M_{system}\) (Equation 1).

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

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.

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.

Widefield Axial (Z) Resolution: Axial resolution refers to the optical resolution along the optic (Z) axis, and calculated according to the Rayleigh Criterion\(^3\).

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?

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?

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?

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.

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

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.

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??

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.

For widefield imaging, the Rayleigh Criterion for lateral resolution, \(r_{lat-WF}\), can be found using Equation 7, where \(NA_{obj}\) is the numerical aperture of the objective, \(NA_{cond}\) is the numerical aperture of the condenser, \(λ_{em}\) is the detected wavelength (emission for fluorescence). \(λ_{em}\) is assumed to be 546 nm for diascopic (transmitted light) imaging, corresponding to the center wavelength of light allowed to pass through a typical green interference filter.

Your cylindrical number is very small and most times people dont need it. however, if you feel comfortable with these glasses there is no harm at all in wearing them.

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..

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?

Expressing the pinhole aperture diaphragm opening in terms of Airy Units (AU) is simply performed by finding the ratio of the back-projected pinhole radius (BPPR), which accounts for the effects of magnification, to the radius of the Airy disk (\(r_{Airy}\)), as shown by Equation 16 below. Please note that you should use \(BPPR_{point}\) for point-scanning systems and \(BPPR_{disk}\) for spinning disk systems in place of BPPR when calculating the number of Airy units using Equation 16.

Dear Zay, most likley you will benefit from a surgery called ICL. You can read about this on our website itself. How old are you ?

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.

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

Its a very small power and most likely wont increase so dont worry. However, it wont go away on its own. You may have to wear contact lenses to be able to see the ball clearly.

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).

\(BPPR_{point}\) is found simply by dividing the real pinhole radius, \(r_{pinhole}\), by the objective magnification, \(M_{obj}\) (Equation 13). Note that with standard point-scanning confocal instruments, users almost never introduce any real optical magnification beyond that provided by the objective lens. This is because additional ‘magnification’ in point-scanning confocal microscopes is almost always best realized using ‘scan zoom’, where the beam is scanned over a smaller portion of the confocal aperture.

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?

The Rayleigh lateral resolution limit (\(r_{lat-conf}\)) for a confocal microscope can be estimated using equation 19. As the number of AUs approaches 0, the scaling factor \(C_{lat}\) approches its lower bound value of about 0.436, which represents a 1.4x increase in resolution over the usual coefficient of 0.61, as used in our widefield Rayleigh lateral resolution equation from earlier (Equation 8). 1.2 is chosen as an upper limit because this is where the resolution response curve levels off, approaching a value of 0.61 and above which we clamp the scaling factor at 0.61 (Equation 19). The only difference from the widefield Rayleigh limit equation is that we use excitation wavelength instead of emission for our confocal resolution measurements.

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

Airy Disk and Airy Units: The Airy Disk is the 2D (XY) diffraction pattern formed by imaging a point emitter, and has a radius measured as the distance from the central Intensity maximum to the first diffraction minimum (dark ring), and whose diameter constitutes one Airy Unit (AU). This is an important concept, especially for confocal microscopy, where the pinhole aperture diameter is generally described in terms of AU. The pinhole aperture is what gives the confocal microscope its optical sectioning ability, and adjustment of its diameter directly modulates both XYZ resolution and optical section thickness. The radius of an Airy Disk, \(r_{Airy}\), can be calculated using Equation 15, which you may notice is essentially the same as the widefield Rayleigh lateral resolution from Equation 8.

- 0.50 eye prescription how bad is that

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?

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

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?

Cylindereyesight

normal eye sph, cyl axis

‘System magnification’ (\(M_{system}\)) includes magnification by components occurring between the disk and the specimen, which does affect the back-projected pinhole size (important for confocal optical sectioning and resolution enhancement), just like the objective lens. ‘System magnification’ is often provided by a tube lens (e.g. a 1.5X tube lens instead of the standard 1X), relay optics in the spinning disk confocal system, etc.

‘Camera relay’ (\(M_{relay}\)) applies to magnification that occurs after emission light is collected through the pinholes of a spinning disk. Since this magnification does not occur between the disk and the sample, the back-projected pinhole size is unaffected. However, the resulting confocal image is still magnified on the detector, affecting the sampling rate on the detector. Usually, ‘camera relay’ magnification occurs between the spinning disk scanner and the camera in the form of a camera adapter.

Calculating the equivalent back-projected pixel size for a point-scanning confocal microscope, referred to as ‘virtual pixel size’ (\(pix_{virt}\)) here, is described by Equation 12. The confocal aperture is the maximum scan area of the instrument at 1X magnification. \(pix_{virt}\) is calculated by dividing the width of the confocal aperture (\(aperture_{conf}\)) by three factors: the number of ‘active pixels’ (the number of times the signal from the specimen is sampled during a single sweep across the width of the scan area, \(pix_{active}\)), the magnification provided by the objective lens (\(M_{obj}\)), and the 'scan zoom' (the percentage of the width of the confocal aperture over which the beam is deflected in scanning the sample, \(zoom_{conf}\)).

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.

For widefield episcopic (reflected light, epifluorescence) imaging, the objective also acts as the condenser. This allows us to simplify Equation 7 to Equation 8.

what is sph, cyl and axis in eye prescription

In order to help avoid confusion with optical sectioning in a confocal microscope, we only provide DoField calculations for widefield imaging scenarios in this tool.

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.

For widefield diascopic (transmitted light) imaging, axial resolution (\(r_{ax-WF}\)) may be calculated using (Equation 9), where \(NA_{obj}\) is the numerical aperture of the objective, \(NA_{cond}\) is the numerical aperture of the condenser, \(\eta\) is the refractive index of the immersion medium, and \(λ_{em}\) is the detected wavelength (emission for fluorescence). For the purpose of this tool, \(λ_{em}\) is assumed to be 546 nm for diascopic imaging, corresponding to the center wavelength of light allowed to pass through a typical green interference filter.

Back-projected pinhole radius is slightly different to calculate for a spinning disk confocal system (Equation 14), as you do also have to account for additional magnification that may be introduced between the actual spinning disk and the sample (\(M_{system}\)), in addition to that provided by the objective lens. Unlike point-scanners, this is not uncommon for spinning disk systems. Note that additional magnification provided by camera adapters located after the spinning disk and before the camera doesn’t affect the back-projected pinhole radius, so is not included in the calculation here (though it is accounted for when considering the sampling rate on the camera).

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.

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

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.

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.

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.

Eyecylinder

What is normal eye axis

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.

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.

Magnification: Total system magnification is found by multiplying the magnification provided by each component in the optical system. Most of the magnification is usually provided by the objective lens (\(M_{obj}\)), but additional magnification may be introduced at various points in the system.

Difficult for us to say what the issue is by this one line. THere could be multiple reasons. You may need a number check up again.

Depth of Focus: Depth of Focus (DoFocus) is conceptually similar to Depth of Field, but is instead evaluated at the detector plane rather than the object plane. We must account for the longitudinal (axial) magnification of the optical system, as well as any change in refractive index between the detector medium (\(\eta\) = 1.0) ) and the object immersion medium. This is found using Equation 6 below.

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)

- 1.50 eye prescription how bad is that

Even if you dont wear glasses you will be fine or you could wear blue blocking glasses which may offer some mild benefit.

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.

The sampling rate is calculated in one of three ways, depending on whether or not it's a widefield (\(f_{WF}\), Equation 22), spinning disk confocal (\(f_{conf-disk}\), Equation 23), or point-scanning confocal (\(f_{conf-point}\), Equation 24) instrument.

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.

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

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.

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.

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 ?

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?

\(r_{ax-conf} = \begin{cases} \frac{1.43\eta\lambda_{ex}}{(NA_{obj})^2}, & AU\le 0.3 \\ \frac{2{\eta}C_{ax}\lambda_{ex}}{(NA_{obj})^2}, & 0.3\lt AU\lt 2.5 \\ \frac{2\eta\lambda_{ex}}{(NA_{obj})^2}, & 2.5\le AU \end{cases}\) (20)

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.

For this tool we have estimated fits for both the lateral and axial response curves, where the dependent variable is the scaling factor to be used when calculating resolution and represented by \(C_{lat}\) (Equation 17, Figure 1) and \(C_{ax}\) (Equation 18, Figure 2), respectively. We have scaled these curves to match the Rayleigh Criterion instead of full width at half maximum (FWHM), as originally presented. A \(4^{th}\) order polynomial is used to provide a reasonable estimate of \(C_{lat}\), and a \(6^{th}\) order polynomial for \(C_{ax}\).

The axial resolution limit \(r_{ax-conf}\) for a confocal microscope can be estimated using Equation 20 where it is calculated using different functions if AU is less than 0.35, between 0.35 and 2.5, and more than 2.5. From 0 to 0.35 AU the scaling factor is clamped at 1.43, representing a 1.4x increase in resolution over the scaling factor of 2 used when calculating widefield axial resolution. Above 2.5 AU the axial response curve levels off, so we clamped the scaling factor to 2, as used for the widefield Rayleigh axial resolution (Equation 10).

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.

The Rayleigh Criterion\(^2\) is a generally accepted metric for calculating the resolving power of an optical system. According to the Rayleigh Criterion, the closest possible spacing between two identical point-emitters at which they can still be considered optically resolved occurs when the point of maximum intensity of one emitter (peak of the Airy disk) overlaps with the first diffraction minimum of the other (first dark ring).

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.

Confocal Microscope Resolution: The resolution of a confocal microscope is less straightforward to estimate than the typical widefield case, and is a subject that has been extensively explored. It has been shown that, while the information content of confocal fluorescence images in the spatial frequency domain is theoretically double that of widefield fluorescence images, when considered at practical signal levels in the spatial domain the improvement is closer to a factor of 1.4 (in XYZ), assuming an infinitely small pinhole aperture\(^{4, 5}\).

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

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.

Widefield Lateral (XY) Resolution: Lateral resolution refers to the optical resolution in the XY directions and is calculated using the Rayleigh Criterion in this tool.

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.

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?

Sampling Rate: This term originated in the field of signal processing and is formalized by the Nyquist-Shannon Sampling Criterion\(^6\), which states that in order for a given frequency (single sine wave) to be reconstructed, it must be sampled at least twice. For example, in the realm of digital imaging, this means that if the calculated optical resolution is 200 nm, then the pixel size must be 100 nm or smaller in order to properly sample the finest details. In practice, a sampling rate of 2.3 – 4X is a more commonly recommended range for high resolution imaging.

For widefield episcopic (reflected light, epifluorescence) imaging, the objective also acts as the condenser. This allows us to simplify Equation 9 to Equation 10.

Figure 1. The relationship between lateral resolution in a confocal microscope and pinhole diameter, normalized to the Rayleigh Criterion for resolution.

Confocal Optical Sectioning: Confocal optical sectioning is calculated using an equation previously described\(^5\), where optical sectioning is considered in terms of contrast transfer with increasing defocus, accounting for the effect of the pinhole in blocking out-of-focus light. As with axial resolution, we scale a version of their equation to coincide with the Rayleigh limit instead of full width at half maximum (FWHM) in order to estimate optical sectioning (\(\Delta z_{conf}\), Equation 21, Figure 3). This equation only fits the response up to a pinhole diameter of 3 AU, above which optical section thickness is not provided.

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.