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Question: What’s normal corneal thickness and why do we check it?

Answer: Normal corneal thickness is about 540 microns (half of a millimeter). Thickness is checked with a handheld ultrasound device called a pachymeter.

We check corneal thickness mainly for two reasons:

1. People with thin corneas (500 or less) are at a higher risk for having glaucoma. The mechanism for this is not entirely clear.

2. Cornea thickness allows us to callibrate our applanation tonometer readings. The goldman tonometer (the device with the blue light on the microscope) checks eye pressure by pushing on the cornea. This is analogous to kicking a car tire to estimate the air pressure. However, if you drive a truck with a thick rubber tread on the tire, the tire “feels” harder when you kick it. Likewise, if you have a thick cornea, the pressure reading seems higher than it really is.

There are many other uses for corneal thickness, such as determining/following corneal edema and evaluating patients for refractive LASIK surgery.


Is normal 540 nm or did you mean 540 mm?

Comment by Karri — May 6, 2009

Um, nevermind. I figured it out. I’m sorry I said anything.

Comment by Karri — May 6, 2009


Comment by fadi — August 13, 2009

Actually even not nm, but μm !!!

Comment by Kilometer — August 20, 2009

corneal thickness about three fifths of a millimeter in the center and reaches to one millimeter at the periphery

Comment by Dr.A.G. Daudpota — February 25, 2010

I had a Dr. tell me my left cornea measured in the high 600’s. What does that mean? He immediately told me I had Fuch’s dystrophy. Another Dr. said I don’t. What other things can a thicker cornea mean?

Comment by Cheri — April 19, 2010

Please let me know how much min thickness of cornea should be left after lasik surgery

Comment by Aarti — November 29, 2010

hi, i recently visited the hospital for a pre-checkup for lasik. They asked me to remove my soft toric contacts and wear glasses for a week before the checkup. But my doctor forgot and gave me an appointment within that week. So on the day of my appointment i wore glasses only for 5 days. My corneal thickness measured 496 and 498. So she said we will check again after 5 days and measure the thickness. I really want to get lasik done. But am worried whether i will reach 500 microns for both eyes even after 5 days waiting. Please respond.

Comment by swathi — December 21, 2010

I have been doing Ophtholmology as certified tech, surgical tech, and a CEBT for about 20yrs. when i was working for a Dr. in San Antonio when a person came in to see if they met the criteria for lasik’s and they were wearing contacts, we would ask them for how long have they been wearing cl’s and if they could stay out of them for 2week or 3 so that the cornea would allow its self to come back to its normal shape. By doing this gives you a more accurate corneal photography.make sure that they get a base line to see the change after 2 to 3 weeks. People who wear hard cl’s is best to stay out of them a month.

Comment by James — February 11, 2011


Does the corneal thickness change from one reading to another?

Comment by Liz Snavely — August 12, 2011


good after sir ,i had an eye test on 01/11/2010 for laser treatment, but doctor told me that i have a 426 and 432 micron left and right eye .they told it is not possible for treatment so ,continue with ur eye glass,now the days are passed now my microns wheather any changes will happen or not.plz respond me as soon .

Comment by prathap — September 6, 2011

if u hv thin cornea u may be suffering from keratoconus.. U should go for c3r operation. Im suffering from keratoconus n goig for this operation in center for sight. Safderjung. B 5/24. Delhi.

Comment by sunita — January 1, 2012

U can contact me on decembersunita@gmail.com. I was searching measurement for healthy cornes.

Comment by sunita — January 1, 2012

my corneal thickness is 514 & 518, so is this thickness ok for c-lasik surgery or an e-lasik surgery is required?

Comment by neha — March 1, 2012

I was told by my regular ophthalmologist that I had Fuchs. I joined a support group for Fuchs who encoraged me to see a corneal disease specalist. I did and he told me that I didn’t have Fuchs. His report: no edema or guttae either eye. corneal thickness, R/575 c/w normal, L/581 c/w normal. I went in to my reg. ophth. initially, with pain (something in my left eye)& blured vision in my left eye. It turned out to be loose tissue on the cornea with an infection. The tissue was finaly scraped off and the eye was treated with antibiotics. It cleared up and I am seeing fine now. The specalist said that I had Map-Dot not Fuchs. My corneas are above average in thickness but does this mean that I have edema. What’s your read in this. Dave Green

Comment by Dave Green — March 18, 2012

I just had my corneal thickness measured at 690 in my left and 680 in my right. The ophthalmologist said that my reading was off the chart and he had never seen a reading that high. My only symptoms were higher than average eye pressure in both eyes (22/25), which is why they did the corneal thickness test. He is going to test me next week to rule out any diseases (like Fuchs) that could be affecting the corneal thickness. I’m wondering if the readings could be normal for me or does a reading that high necessarily mean I have something else going on? I’m a 48 year old male and other than needing glasses for reading as I get older, I’ve never had problem with my vision.

Comment by Craig — April 10, 2012

my orbscan readings are OD:510microns,OS:520microns.to prevent glaucoma in future,whether LASIK is advantageous or PRK.

Comment by rifil123 — May 14, 2012

may i know the ideal corneal thickness to undergo lasik.mine is 526mns and 53omns.Am i a sultable candidate for lasik

Comment by priya — June 21, 2012

My corneal thickness is about 525 micron both eye. My power is around -8. Should i go for lasik ?

Comment by alka — September 5, 2012

My cornea thickness is 490nm and apparently I’m suitable for LASIK do you think this is right?

Comment by Hevs1shaw — September 30, 2012

I gone for lasic but doctor told im not fit for lasic. Because my corneal thickness is R/449 (-4.75) and L/442 (-5). Plz tell me ICL suites for me or not? And im 26y. If il wait for some more months is my corneal thickness will increase?

Comment by Latha — March 13, 2013

my corneal thickness is 442 both eye. and my power R-4.75 L-4.50 is my corneal thickness will be increased by time ? could you tell me about my options for the operation ????

Comment by Mariam Helmy — March 23, 2013

my corneal thickness is 496 OS and 505 OD.. I wear glasses
My corneal thickness is gradually decreasing..

Would u plz suggest me what could be the best option for me?

Comment by rk — March 24, 2013

What is the thickest part of the cornea? (center, periphery?)

Comment by Ernesto — May 15, 2013

My corneal thickness is 462 and 470 and I gone through this test after wearing glasses for 1 week before this I used to wear contact lenses from last 5 yrs.Can u pls suggest any medicines for thickness of cornea so that i can go throug lasik or prk after some time period.

Comment by Mahak Arora — May 30, 2013

decreasing cornea thickness may be due to increased exposure to ultraviolet light in our lives through tv,pc,phones,tubelights,sun etc. as some websites suggest as a possible reason for keratoconus. Avoiding uv light as much as possible and Using a photochromatic lens may be good. Also, increased anti oxidant intake in food may be as the cr3 operation does that. One hopes that precise cause and cure for keratoconus is found soon.

Comment by abdul — June 9, 2013

does corneal thickness reduce after lasik surgery?

Comment by priyanka — June 17, 2013

0.5 mm is 500000nm. Could you have meant 540microns?

Comment by T Yomi Obidi — July 9, 2013

how we control the corneal thickness?

Comment by syed mohammed ali — July 24, 2013

My inital pressures for this last visit were 22 & 24.

(Two years ago, they were 29 & 27)

The doc measured my cornea thickness and calculated that we should take 7 POINTS OFF of my pressure score because my corneas are extra thick. That brings my score to 15 & 17. I wonder why my corneas are so thick.

I also have Sjogren’s syndrome, just had punctal plugs put in. A friend of mine — who also has Sjogren’s — suggested that I might have Fuch’s Corneal Dystrophy,and to bring it up at my next visit.

What do you think? Should I bring it up and ask to investigate……or is that not in the ball park?

Comment by Dandelion — July 25, 2013

My corneas are 652 and 653…my optician was fairly wow’d! :) woo go thick corneas!

Comment by Virtah — September 14, 2013

my cornea thickness is 486microns. Cant I get lasik surgery done?? PRK is too costly:(

Comment by Madhuri — October 2, 2013

Measurement of central corneal thickness with OCT or Pachymeter is always nesscessary to ascertain the true IOP.The peripherial cornea is thicker than the central cornea.

Comment by Charles — October 5, 2013

I Like Blind Freinds. Plz Contact Me- gul.khanindia@gmail.con

Comment by GUL — October 19, 2013

I having corneal thickness 479 for one eye and 491 for another eye is there any possibility to increase corneal thickness and any possibility of doing laser surgry and my age is 23 years

Comment by dwijesh — October 31, 2013

My con thicknes 450 and some time isee flash light in my eye

Comment by mhmoudbadr — November 8, 2013

My corneal thickness is 462.Can i go for LASIK???if no then what is option???

Comment by Deepika — November 24, 2013

Hi i live in faridabad..wearing contacts from last 5 years. want to have lasik but my corneal thickness is 516 .deepika or madhuri im also in grief sob sob.

Comment by arvind — December 13, 2013

What is the normal progression thickness of the corneal related to the thinnest locate?

Comment by Khalifa — December 14, 2013

One time I went to the eye doctor and while checking my eye pressure they started panicking because I wasn’t even old enough to drive at the time but I had crazy high eye pressure like a 60 year old with glaucoma. Turns out I just have a corneal thickness of like 685nm which freaked my doctor out anyway. He told me to check for a world record and I still don’t know if he was kidding.

Comment by julia — January 11, 2014

hi my cornial thickness is 476 or 483. and my eye sight is too weak left eye sight is 11 right is 4 plzzz help

I want my vision better

Comment by fizza — February 4, 2014

My corneal thickess is 475&488.i want to lasik.but at old age.any problem will occure

Comment by nares — February 17, 2014

I have corneal thickness 620 and presser @ 24 and 21 both eyes.What does it means.

Comment by kapil — April 13, 2014

My cct is 470 for both eyes .so is LASIK suits for me .hospital people told me there is no pblm .is there will be any pblm

Comment by Sandesh — April 23, 2014

am 24,yesterday i have lasik test ,doctor suggested not to go for lasik as my cornea thickness is too less 469 & 476 ,is there any possiblity to increase cornea thickness ?

or any other treatment to get rid of the spectacles?

plz plz suggest me ,am too frusted with this news

Comment by munna — June 12, 2014

What is the correct procedure for getting the Average Corneal thickness reading after taking 5 readings for each eye.

Comment by Kelly — September 6, 2014

hi sir/madam i had contacts from 8 years recently i went eye hospital for checkup. the doctor send that your corneal thickness is 466 and 470, it is not possible range to go for lasik tretment but i want go for lasik tratment. there any other possibility for lasik. how do i increased my corneal thickness.

Comment by radhika — September 7, 2014

sir my conical thickennes is 470 for both the eyes so is lasik suits for me plz give me any suggestions

Comment by swathi — October 9, 2014

my glaucoma doctor took visual fields test plus iop14 in both eyes looked in back of the eye after they were dlated.
I see blurry in my left eye . he said there is nothing that can bw done to improve my vision. He said ny corneas are thick , but I got no numbers. Did he check for the thickness? in my cornea?

Comment by marcella ilipff — October 10, 2014

the accurate normal corneal thickness is 556 microns.

sandesh.. you should ask your doctor. its diagnosing differ from doctor to other.. just your doctor decide that!

Comment by michael — October 16, 2014

I had an appointment with my optometrist today. The eye pressure machine kept measuring pressure above its capabilities. After confirming the high pressure with the hand held “probe”, the optometrist decided to measure the corneal thickness in case the pressure reading was off. Corneal thickness came in at a whopping 700 – 714 and I was told it was the highest reading that they had ever measured. Looks like everything is fine and no problems with my vision other than astigmatism.

Comment by JF — November 14, 2014

My corneal thickness was 490 microns and power -8 in both eyes.so they told laser is not possible because of thin cornea.it has become six months I checked. I am using specs for past six months.Will my thickness be increased now? Will I be eligible for lasik

Comment by rk — December 26, 2014

Can eye cross linking help in the cornea wich thickness is 470 ?

Comment by hanan — January 26, 2015

My corneal thickness is 489 in right eye and 481 in left eye

Comment by Bhat Kouser Female — January 31, 2015

Everybody here with cornea under 500 check for sure if you dont have Keratokonus. If yes ask your doctor for corneal crosslinking ASAP. So you can save your vision.

Comment by Ajgormy — January 31, 2015

in high myopic case(more than -5.00Ds)central corneal thickness will increase or decrease(cornea thin or thick)???

Comment by lintu — February 12, 2015

I’ve got you beat, JF. Both of my eyes measure 780 microns. My normally serious eye doctor was downright giddy. I’ve always had abnormally high pressure and he was the first to check my corneal thickness.

Comment by Allison — April 28, 2016

Thinner than average cornea means that there is less tissue to “sculpt” the surface with laser to create the change in power you will need to correct your vision. Depending on just HOW thin, it might be impossible to correct your vision fully with laser or it might not be advisable to do any. If, however, they are just below average AND you only have a prescription of -1.00 or -2.00, it MIGHT still be possible to offer you a full correction. If your cornea is unusually thick and all pathological causes ruled out, such as any dystrophy like Fuchs, or oedema from corneal damage from too much contact lens wear or injury, you can sometimes have quite a lot of myopia fully corrected but I cannot ever remember seeing anyone with an Rx of -8.00 being fully corrected. Again, however, anyone who is -8.00 can do NOTHING without their specs or contacts. They can see no further than a few inches away clearly. Such a person could have the maximum correction with lasik, still be -3.00 but feel they are still MUCH better off than before because they can see a lot better even if not perfect. They can get up to care for a crying baby without their specs, make it to the loo without falling over something. For these people. I regularly see patients with corneas 640um and there is no pathological reason, they are just thick. Similarly, thinner corneas are not necessarily caused by disease. Mother nature at her best….she does like to keep it interesting. If you are diagnosed with Keratoconus, do consider collagen X linking. It really is a sight saver. The alternative of waiting until you are almost blind and having a corneal graft seems so barbaric now and yet until a couple of years ago, that was your only option.

Comment by Jan Rae — May 17, 2016

The reason why people with thin corneas might be at higher risk for glaucoma might be due to misreading of IOP when corneal thickness is nor properly accounted for and underdiagnosis (see http://www.glaucoma.org/glaucoma/the-importance-of-corneal-thickness.php).

Comment by Io — October 30, 2016

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