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Cactus Jack 14 Jan 2017, 00:26
When I was getting ready for the surgery, they used an ultra sound probe that very lightly touched the Cornea to measure the structure of my eyes after administering anesthetic drops so I would not feel the touch. The reason for the very light touch to avoid deforming the Cornea by any pressure. The dimensions of the structures of the eye are small and the lenses involved are very strong. For example, a 1 diopter refractive error is typically the result of a 0.3 mm error in the distance from the crystalline lens to the Retina.
With those dimensions they can calculate the IOL power needed to achieve the desired prescription. However, IOLs only come in 0.50 diopter increments and the measurements are not super precise. They can get pretty close, but they don't always wind up with the exact target prescription. Sometimes the prescription is fine tuned using Lasik.
SC 13 Jan 2017, 11:00
My mother has developed cataracts. Her best eye has gone from +2.25 to around -1.00 - I can tell because I'm hyperopic and can see distance through the reading segment. Her worst eye (+2.75) is quickly heading in the same direction.
She was offered the chance of the op last year but said no (I don't know why) but has gone back this year and been given a wait of 4 weeks for the op on NHS in UK.
Seems to be 3 parts:
- first consultation - explain the procedure and risks
- meet with the guy who is going to do it - lots of eye drops
- then the op itself
I'm not sure how they get an accurate rx - I assume the crystalline lens has puffed up to go from +2.25 to -1 and I don't know how much it will reduce again after the cataract material is removed
Cactus Jack 12 Jan 2017, 18:54
In the -4.00 to -4.50 range for distance.
Glasses questions 12 Jan 2017, 17:30
I think I hold a book about 12 inches away but I find myself holding my IPhone closer - more like 9-10 inches when I am reading things on the internet or text messages. If I got IOL's for perfect close up vision at this range - what would my distance prescription look like??
Cactus Jack 12 Jan 2017, 17:19
The important thing for determining the the final refractive power you need is the distance from your eyes to what you want to see clearly. If you will measure the distance from your eyes to what you want to see clearly, I will do the calculation and suggest what you should ask for.
Glasses questions 12 Jan 2017, 16:30
Thanks for the information. I live near Cleveland, Ohio. When I have cataract surgery at some point I would not go for the multi focal IOL's. I tried multifocal contacts once and did not like them. I get better vision from wearing my progressives. I wear them pretty much full time. I'm minus .75 for distance and have slight astigmatism. My add is now plus 3.0 and I find I can't see much of anything close up. One question I have is if I went for single vision IOL's and had them set for perfect up close vision -I understand I would need glasses for distance and I'm fine with that. I would rather have the perfect close up vision. If I did that - how myopic would I be?? I tried mono vision once and decided that it's not for me. I work as an esthetician doing lots of close up tasks with facials, waxing eyebrows and makeup.
helpful 12 Jan 2017, 02:05
If the contributor is living in the UK then he can wait a long time for an operation for cataract surgery although the operation is easily done. This is due to pressure on the National Health Service so they delay many people treatment unless you pay to go private. This applies to other forms of simple surgery like hernia
Cactus Jack 11 Jan 2017, 22:18
By the way. With Mono vision I can function pretty well with out my glasses. One eye is close to 20/20 distance vision without glasses and the other eye is mildly nearsighted at about -1.50. When I want to see really well, I wear trifocals because I the type work I do. My vision with glasses, after the Cataract Surgery, is better than 20/20. On a good day I can read most of the letters on the 20/15 line and one or two on the 20/10 line. Not bad for a 79 year old.
Cactus Jack 11 Jan 2017, 22:12
+3.00 is not a particularly strong add, if you are developing Cataracts. Presbyopia is really the gradual stiffening of the protein that makes up your Crystalline Lenses, that are part of your Auto-Focus system. Cataracts just make that stiffness happen quicker. At some point, your add is really determined by your preferred reading distance. +3.00 focuses at a distance of about 33 cm or 13 inches. You many have noticed that OTC Readers are usually available up to about +3.50, which focus at about 28 cm or 11 inches. Stronger prescription glasses or "clip ons" are available.
If you are developing Cataracts, is there any real reason for waiting to get Cataract Surgery? In the old days, before IOLs, they used to wait until the Cataracts got "Ripe" or get very hard before removing the lens and lens capsule. That operation was a very serious one that required months for recovery. I really think they were hoping the patient would die before they actually had to do the surgery. When the lens and lens capsule are removed, you have to wear very strong PLUS glasses.
Today, Cataract surgery with IOL replacement lenses is almost a non-event. The surgery takes about 10 minutes IF the Crystalline Lens is still soft enough to be easily emulsified and sucked out. It takes longer if the lens is harder. The Capsule is left in place and the new lens is actually inserted in the old capsule through a very tiny incision (3 mm) in the side of the cornea. The surgery is so safe and easy that some people are opting to have their stiffening Crystalline Lenses removed and multi-focal IOL lenses installed, long before they actually need Cataract surgery. The operation is exactly the same and Cataract surgery will never be necessary. Be aware that multi-focal IOLs are not for everyone.
I had Cataract Surgery with single vision IOLs for Mono Vision in July of 2001 and have never regretted it for an instant. I can fully understand any reluctance about the surgery. I was very nervous about the surgery, but didn't have much choice. As I said the surgery was a non-event. I was moderately nearsighted before the surgery, but that was pretty much fixed by the choice of the IOL power for that eye. I took the lens out of my glasses for that eye and drove myself to the doctor's office the next day. He was pleased with the results and my big question was "When can you do the other eye"? He said two weeks. My response of That Long?? If he had said tomorrow, I would have been happier. I really didn't want to wait, but he wanted to make absolutely sure everything was OK before doing the other eye.
Based on my experience, if I needed Cataract Surgery in 18 months, I would want to do it next week so I could enjoy 18 more months of good vision.
May I ask where you live?
Please feel free to ask more questions if you need to.
Glasses questions 11 Jan 2017, 20:34
Hi - I have some questions that I'm hoping I can get some help here. I'm 49 years old and first got glasses at 45 - progressives with a plus 1.0 add . Last year my ECP said I now needed an add of plus 3.0. I was having a difficult time reading smaller print. I was also diagnosed with cataracts in both eyes. Will my add continue to go up?? He wanted to see me in 18 months. I feel like I am again beginning to struggle with small print. But is a 3.0 add already quite strong for my age??
Cactus Jack 11 Jan 2017, 02:20
I believe you have it backwards. It is the eye (Ciliary) muscles of a person who is very myopic, that are already relaxed. They are often so weak that they have trouble focusing close, when they get Minus glasses to correct their distance vision.
It is people who have Hyperopia or Latent Hyperopia, who need for their Ciliary Muscles to relax when they get Plus glasses.
CotGlasses needs t strengthen his/her Ciliary Muscles. We do not know if he/she has the full prescription. The +1.00 add is about right for the distance from his/her eyes to the computer, but it is a little awkward to tilt the head back to look thru the segment for the computer, but the +1.00 is not nearly strong enough to enable focusing at a normal reading distance.
In this situation, the ECP should probably have prescribed "functional" trifocals that are a little weaker than would be prescribed for an older person with advanced Presbyopia. Something like a reading Add of +2.00 and an intermediate segment of +1.00. As the Ciliary Muscles get stronger over a few weeks, the Add powers could be reduced and eventually eliminated.
A really good and inexpensive solution is to get some Clip-on Magnifiers from RxSafety Glasses. They are available in a nice assortment of powers and, if you do have the ability to focus, you can work your way down in power as your Ciliary Muscles get stronger.
I have no ability to focus after Cataract Surgery and normally wear trifocals. I have both Clip-ons and single vision Reading Glasses. GotGlasses should not need focusing help for very long, but Clip-on + lenses might slow Myopic Progression that is sometimes exacerbated by extended periods of focusing on a computer display or reading.
George1968 10 Jan 2017, 17:32
You will have a period of adjustment because this was quite a prescription to start with! I have no idea how you were able to function, particularly in school. Your eye muscles have been straining hard for years to see, and now they have to relax.
It won't take long - a week or two. Your eye muscles have to relax and your brain has to be re-trained a bit to interpret the new visual stimuli.
There is good news and bad news. Eventually, you will be able to see and to get rid of the bifocals (at least until you are in your 40s. The bad news is that you will likely need stronger glasses in six months. Once your eye muscles relax, your sight will go to its true prescription. So, you will likely go to about -6.00.
How old are you? Are you male or female? Besides enjoying the new clarity, how are you adjusting to wearing glasses full time? What have been the reactions of people to seeing you in glasses?
Good luck and be patient.
GotGlasses 10 Jan 2017, 15:28
I am using the bottome part, under the line to read, but it is still difficult. The bottom part is great for seeing the computer screen, better than the top, but none are working for reading.
Soundmanpt 10 Jan 2017, 14:50
I think what you may not be doing is using the add segment of your glasses and instead you're trying to read using the distance part of your glasses. What you should be doing is not moving your head down when you are reading something, but only moving your eyes downward like your trying to see the very bottom of your lenses. So that means your head should be looking straight out ahead of you, but your eyes looking down through the lowest part of your glasses. That is the area you need for reading small print. Does this make sense to you? It takes a little bit of practice but in a very short time learning what part of your glasses to use for distance and for reading will become very natural and you won't even have to think about it. But for now you will have ot thinks when you start to read from a book.
GotGlasses 10 Jan 2017, 12:47
If it is only going to be for a week, I will tough it out. Hopefully it gets better.
Cactus Jack 09 Jan 2017, 18:00
I think I may have mentioned that you might have that problem. Because of your prescription, your Auto-Focus has not had to do anything to help you focus close. It will take a few days for your Auto-Focus system to re-learn how to do its job.
One thing you can do is get some over the counter reading glasses and wear them over your new glasse. I would suggest the lowest available power, but you may need to try on something in the +1.50. Hopefully you will only need them for a week or so.
There is a company in New Jersey, RxSafety Glasses that sells Clip-On Magnifiers (Reading Glasses) in powers as low as +1.00. The are about $15.00 each. You might find them useful on a temporary basis.
If you need more suggestions, let me know.
antonio 09 Jan 2017, 15:06
That´s a bit of training only hopefully,
it´s because you waited for so long to get them,
best regards, antonio
GotGlasses 09 Jan 2017, 14:58
As I started doing school work today, I realized that it is very hard to read with my glasses on. The supposed reading section is great for the computer, but not a book or papers. Now I am just confused. I finally get glasses glasses and now I cannot read with my glasses.
Likelenses 08 Jan 2017, 22:58
-1.75 are a bit stronger than most first prescriptions. Most are in the neighborhood of -.50, to -1.00, so you have been nearsighted for a few years.
As Cactus Jack has stated you really should wear them constantly.
Being that this is your first prescription, the doctor may have prescribed glasses a little weaker than you actually need,and you may find your vision blurred again in six months or so. If so, have another exam to get an updated prescription.Depending on your age, and what type of work you do, you will probably need stronger glasses about every year,at least for a few years.
If you can tell us your gender, age, and occupation we can tell you a bit more. Also it would be helpful to know if, and how many family members are nearsighted,and to what degree if known.
Maxim 08 Jan 2017, 16:07
to Got Lenses:
Two typos to be corrected:
2) good looking (not got looking)
to Cactus Jack:
Compliments - such a great knowledge, and so nicely said for our young friend here!!
This is so encourageing, bridging the age gap, bridging the distance in space, etc., just a real good friendship and partnership that you offer in this world!
GotGlasses 08 Jan 2017, 16:01
Ny favorite subject is biology. And we have to take math and science classes. I am currently in biology and algebra 1.
Cactus Jack 08 Jan 2017, 11:38
Congratulations, welcome to being able to see this amazing, incredible world where we live. You have not mentioned if you live in a city or not, but I think you will be even more surprised at what you can see at night. It is now winter in America, but just wait until spring. You are in for a wonderful treat. The night sky is often super clear on a winter night. It is filled with millions of stars, a few planets, and of course the moon. Things you can see without a telescope or binoculars. Most are so far away that the distances are measured in AU, Astronomical Units (the average distance from the Earth to the Sun) or in Light Years. The light from the nearest star takes 4 years to get here.
The brief double vision and the unstable images (lets don't call it Nystagmus, yet) could be related or completely different causes, including blurred vision. Your Vision system, Eye Position Control System, Focus Control System, and Vestibular (balance) System are amazing, complex, and interconnected systems in your brain or are very close to your brain. Sometimes it is very difficult to isolate the systems because of the interactions. Problems in the separate systems can sometimes have similar symptoms.
The first thing to is correct your Vision, which you are doing with your new glasses. Many times, correcting vision problems will let other things, such as you have described, simply go away. As a doctor friend of mine said, "The body can correct about 85%f the things that go wrong. Sometimes the best thing is to just let the body heal itself. The trick is to know which is the 85% and the 15% that will only get better with help."
Being Myopic (nearsighted) with Astigmatism is one of the things where the body needs help to see. I suggest you give it a few weeks before worrying about any other problems. You mentioned that things look smaller and farther away with your glasses. That is an optical phenomenon caused by Minus lenses. Plus lenses make things look bigger.
I mentioned previously, that you have built in excess Plus around +5 to +6. That excess Plus makes you see things blurry and larger than they actually are. The Minus lenses in your glasses neutralize or cancel out the excess Plus and make the images on your Retinas slightly smaller than normal, but in focus and very clear. As Soundmanpt said, in a few days or a week, that sensation will go away.
You mentioned that you were in the 9th grade. May I ask your favorite subjects? Have you had any science or math courses?
Maxim 08 Jan 2017, 11:09
to: Got Glasses
I'm so happy for you. You're saying, this was one of the best days in your life.
I sometimes have checked with +6.00 contact lenses, and -6.00 glasses over them, how a person could see (I wanted to find out, how my daughter could see), and I cant imagine, that you have been such a long time without adequatre glasses.
So my gratulation - hope you always find nice glasses for good vision and got looking (that's important in your age as well!).
Soundmanpt 08 Jan 2017, 09:57
I'm sure that you were quite shocked when you put your glasses on for the first time. You now are seeing all the things you have missing. That effect that you are noticing that everything is looking smaller and a bit further away is very normal. Your eyes are still adjusting to your glasses and that may take a day or two before everything looks normal with your glasses on. by the end of the day and you take your glasses off you're going to be amazed at how blurry everything is, even more than it was yesterday. I assume by what you're saying you now understand why you have been getting told that you will be wearing your glasses full time?
GotGlasses 08 Jan 2017, 09:45
What do I do about maybe having nystagmus? Is there any fix? Can that be why I saw two charts for a split second nesr the end of the exam?
GotGlasses 08 Jan 2017, 09:28
I just picked up my glasses!!! Everything looks so clear and detailed,it is phenomenal! I love glasses! I cannot believe what I have been missing out on. This is one if the best days of my life. On the way home I was actually able to read road signs and names, and I noiced the details in so many things! I am so happy. Something weird, though everything looks smaller and i think further. It does not even matter though because I can finally see what I am suposed to!
Cactus Jack 08 Jan 2017, 09:09
You may be experiencing a condition called Nystagmus or what is sometimes called Dancing Eyes. There are several types and causes. Sometimes the cause is not directly related to the eyes, but is caused by the balance system. Sometimes the Semi-Circular canals in your ears that sense head position and motion send incorrect signals to the Eye Positioning System and that causes the eyes to move. Usually, they move back and forth, but can also move up and down.
I suggest waiting until after you get your glasses, to follow up on that. It could also be caused by your Eye Position Control System (EPCS) trying to adjust your eye position. There are several "minor" inputs to the EPCS, but the "major" input is images from your eyes. The EPCS needs sharp images to be able to do it job well. It seems to work by matching vertical edges in the image for horizontal motion and horizontal edges for vertical motion to keep the eyes tracking properly. If the images are not clear and sharp, it is very hard to get the eyes aimed properly. Without clear images, it is an impossible task, but the system tries anyway.
When do you think your glasses will be ready?
Likelenses 08 Jan 2017, 02:16
That is a very strong first prescription. You will be wearing glasses full time.
GettingGlasses 08 Jan 2017, 00:38
Not sure where this fits in or if it is even inportnat, but even though I have never noticed double vision I do sometimes notice what I call bouncing vision. What happens is, like if I am looking at a cup on a table I think I see it with both eyes and it looks like it is where it is, and then it bounces as if I am only seeing it with one eye and then I can bounce it to see it with the other and back to seeing it centere with both eyes. Not sure if I explained that correct, but I hope you understand what I mean.
Cactus Jack 07 Jan 2017, 23:57
Probably nothing right now. You don't seem to have any trouble with double vision with right now. When you get your glasses, there is another test I can suggest in that regard. You may have some slight eye misalignment, most people have a little, but it apparently is easy for you to over come. If you have been reading as close as you probably have, I suspect you might have a bit of excess convergence, but I suggest not worrying about that right now. With your glasses you will be able to read further away and that will reduce the amount of convergence you need and the excess convergence may go away in a few weeks.
It is very likely that you have not been using your Ciliary Muscles for quite some time and you may have some trouble focusing close with your glasses, that is the reason for the +1.00 add. It may take some effort and possible discomfort teaching your auto-focus system to work at full efficiency because I suspect your Ciliary Muscles are very weak.
Near the end of your eye exam, I suspect you were shown a small card with letters on it about 14 inches from your eyes and you had trouble reading it. The examiner added some Plus to help you read it. That is the +1.00 add. Initially it may not be enough until your Ciliary Muscles get strong enough to do their job.
The Ciiary muscles are very tiny muscles inside your eyes. For their size, they are normally the strongest muscles in the body. They are part of your Auto-Focus system and their job is to squeeze your Crystalline Lenses to supply the PLUS you need to focus close, IF you have good distance vision.
Being nearsighted as you are, is like having very strong built in Reading Glasses that you wear all the time. However if you look at over the counter Reading Glasses in the stores, you will notice that they only go up to about +3.50 that is usually the strongest Reading Glasses that anyone ever needs. Your built in reading glasses are in the +5.00 to +6.00 range, not counting your Astigmatism.
If you have problems focusing close with your glasses, please let me know and I will tell you what and when you should notify the examiner.
GettingGlasses 07 Jan 2017, 23:20
I am fairly certain this is my prescription. I already chose them,but the shoo was too busy and they could not get them ready yet, should be done tomorrow. I live in America. I have never noticed double vision before. I did the test, and I got about 4 and a half, to 5 inches. What should I do about the two charts thing? Do I go back and tell the doctor?
Cactus Jack 07 Jan 2017, 21:49
I will try to answer your question about the brief double vision in a moment.
That is a very strong first prescription. It is very surprising that you have been able to get to the 9th grade without some correction. I am wondering if they gave you the correct information.
I am very curious about those numbers. Here is what those numbers mean:
There are several parts to an optical prescription. This is the traditional meaning
First Row = OD (Right Eye) Sphere -5.50, Cylinder -1.00, Axis 120 degrees, Bifocal Add +1.00, Prism blank means none
Second Row = Left Eye (OS) Sphere -5.75, Cylinder -1.25, Axis 005 degrees, Bifocal Add +1.00
The dominant part of this prescription is the Sphere numbers. What they mean is that everything beyond 18 cm or 7 inches is increasing blurry. That would indicate that you are very nearsighted and would be unable to read anything on the board and you would have to hold a book a bit closer than 18 cm or 7 inches to be able to read it. The Cylinder correction just indicates that a person needing these glasses would have moderate Astigmatism, which messes up vision at ALL distances and makes the nearsightedness worse so the distances I calculated above would be even a bit less.
Is it possible that is NOT your prescription? Have you ordered glasses yet?
There is a simple test you may be able to do to confirm this prescription is yours. Hold a book close enough to read and gradually move it away until the text just becomes impossible to read. Measure the distance and let us know what it is.
May I ask where you live and where you got the Eye Exam?
As I stated in "How to Study . . .". you should see two images when the examiner first opens both shutters. Usually, there is significant prism in place to assure that you will see double and the image separation will be enough that you will not be able to fuse the images until some adjustments are made. The typical starting setting is with significant horizontal Base In prism and enough Vertical prism to make sure the images are separated vertically. The Base In prism is gradually reduced to Zero and then increased in the Base Out direction until the two images are aligned horizontally and then the test is repeated with the images separated horizontally and the Base Up or Base Down prism is adjusted until the images are aligned vertically. It sound like that part of the test was skipped. You probably have a little bit of eye misalignment and you probably should have mentioned it. Because you were able to almost instantly fuse the images it is likely that it is not significant, but it should be evaluated.
Have you ever noticed double vision on any other occasion?
Please do the test outlined above and answer the questions. I think we need to chat some more.
antonio 07 Jan 2017, 18:24
wow Getting Glasses,
that aren´t weak ones any more :-)
glad you got them, you too ?
if you like to discuss vision and glasses
to chat a little,
GettingGlasses 07 Jan 2017, 17:25
Sorry that last post was from me. I forgot to put my name.
07 Jan 2017, 17:24
The prescription is a chart on the back of a business card. The numbers in the first row are -5.5, -1.00, 120 +1.00 The second row is -5.75, -1.25, 005 and +1.00. I am 15 years old and am in 9th grade. Something you said in your previous post has cought my attention. During the exam when the doctor opened both eyes I saw two of the chart for a split second, but thrn it became one. I told the doctor I saw one. Is that okay?
Cactus Jack 07 Jan 2017, 16:18
No, not bad. In fact, very good. Just to give you an ideal of what your prescription means, without your glasses the first number (Sphere) -1.75 indicates that everything beyond about 57 cm or 22 inches is increasingly out of focus and the and number (Cylinder) just makes it a bit more blurry.
You should wear your glasses full time, particularly for distance. Your prescriptions mean that you effectively have built in Reading Glasses very similar to the over the counter Reading Glasses sold in many stores. It may be tempting to do close work without your glasses because initially it may be more comfortable than wearing your glasses. That may not be a good idea. It depends on your age and possibly your occupation, which you didn't mention.
If you are young enough that the onset of Presbyopia is not a factor, not wearing your glasses for close work allows your Ciliary Muscles to get weak from disuse. The Ciliary Muscles are very tiny muscles in your eyes that can change the Plus power of your Crystalline Lenses, they are the heart of your auto-focus system. If your Ciliary Muscles are weak, they will cause the symptoms of Presbyopia and you will initially have some trouble focusing close while wearing your glasses. That should not last very long, maybe a week or 10 days as your Auto-Focus system gets used to working like it is supposed to.
Vision actually occurs in the brain. Your eyes are merely biological cameras. Your brain has amazing ability to correct what you "see", but it takes extra work and energy. Your glasses correct the quality of the images delivered to your brain and it no longer has to do the correction process. However, it will take your brain a few days to realize that your glasses are really a labor saving tool and it can apply the image processing and correction task to other things. When that happens, most people thing the their glasses have made their vision worse. That is not true. In many ways, your brain is a biological computer and it as filed away the old image processing program and loaded a new program with minimal image processing.
I urge you to wear your glasses full time for about two week and then make the decision when to wear them. No one can tell you that you MUST wear glasses or that you CAN NOT. The only exception to that is the situation where your vision can affect the safety of others. If you drive, it is very likely that your Drivers License would specify that you must wear Corrective Lenses to legally drive.
Hope this helps and you enjoy your good vision. I think you will be amazed to learn what you have been missing and wish that you had not waited so long to get glasses.
Jenna 07 Jan 2017, 15:34
Got my first glasses on Friday. Prescription is -1.75 -0.25 180
Is this bad? Do I have to wear them all the time?
Cactus Jack 07 Jan 2017, 13:12
Sorry I was not quick enough to give you some advance information about your eye exam. Maybe it will be helpful for your next one.
May I ask your prescription, age, gender and if you are in school, your level?
Not trying to be nosey, but that will help us answer any questions you may have.
Cactus Jack 07 Jan 2017, 12:15
You might find this helpful.
HOW TO STUDY FOR AN EYE EXAM
An eye exam is not like an exam that you might take in school and there is really no way to study for it. However, you can prepare for it and learn about your role in the exam. The best eye exams are a team effort between you and the Examiner. Part of the preparation is to learn what to expect, particularly if this is your first eye exam.
One important thing you need to keep in mind is that the Examiner has no way to experience what you are seeing. He/she has to depend on your answers to questions.
There are two parts to an eye exam. The first part is the Objective part. This part consists of:
1. Taking a Visual History where you describe your vision and the kinds of problems you are having.
2. Checking the internal pressure in your eyes for symptoms of Glaucoma. This is one of the very few parts of an eye exam that is even mildly uncomfortable and the discomfort only lasts for a few seconds. There are two basic ways to do the pressure test.
A. Using a special instrument to lightly touch your Cornea. Not to worry here. Before doing this type of test a drop of mild anesthetic will make sure you don’t even feel it.
B. There is a new type instrument that uses a puff of air directed against your cornea. No anesthetic is required, but the puff will startle you. The puff of air is harmless and there are huge benefits. Detecting Glaucoma early, before it can do damage can save your eyesight.
3. The examiner will also get a preliminary estimate of your refractive error by using an Auto-Refractor or manually by using a small hand held instrument called an Ophthalmoscope or Retinoscope.
The Auto-Refractor is a relatively new instrument that was developed in conjunction with NASA to check Astronauts vision in space. You look into the machine with each eye individually where you will see a scene or a pattern. The machine will adjust its internal lenses to focus the image you see on your retina. The Auto-Refractor only takes a few seconds for each eye and it then prints out your estimated prescription.
Some Examiners prefer to use manual methods that have been used for many years. Using an Ophthalmoscope or Retinoscope and a Trial Lens set or a Phoropter (a fancy machine with a built in lens set), the Examiner will look into your eyes and select the lenses that allow him to see your retina, most clearly.
The object of this part of the exam is to get a starting place for the Subjective part of the exam where you have to describe what you see.
Typically the Subjective part of the exam starts with the Right Eye shutter open and the Left Eye shutter closed.
Step 1 is typically determining the cylinder and axis of any Astigmatism correction you need. This is actually the hardest part of the exam because you will be asked to judge relative blurriness of two images rather than the sharpness of an image.
You will be shown a line of text and a supplemental lens will be rotated into place. This lens is a cylinder lens that is mounted on a 45 degree pivot and can be flopped back an forth to bracket a trial axis or orientation of the long axis of the cylinder lens. The thing that is confusing about this test is that the straight lines (strokes) of the letters will alternate in clarity as the lens is flipped back and forth depending on their direction. I suggest concentrating on an “O” if possible. Depending on your answers, the examiner will adjust the axis knob unit the image you see is equally blurry with the supplemental lens 45 degrees each side of the selected axis.
At this point the Examiner will probably swing the supplemental lens out of the way and may change the cylinder power while asking you which lens in clearer.
For your first exam, you may be uncomfortable asking the Examiner to let you fine tune the Cylinder Axis, but I have found that most will appreciate your wanting to actively participate. The way that works is that he will place your hand on the Axis control knob. This time, you move it back and forth a few degrees looking for the sharpest image. It is a bit like “Fine Tuning” an old Analog TV set or moving the tuning knob on an analog AM radio for the best signal.
The next step is determining the Sphere correction. This is an easy part of the exam because all you have to do is pick the sharpest image, but there is a tricky part. Your auto-focus mechanism will try to help, if it gets a chance. The Examiner has a couple of ways to minimize the action of your ciliary muscles and crystalline lenses.
The Examiner can, in effect, sneak up on your Sphere prescription or he can use drops to Dilate your eyes. Lets talk about sneaking up on your prescription first. There are actually 4 lenses in your eye’s lens system. All of them are PLUS lenses and the total power is about +56 to +60 diopters. The only variable focus lens is the crystalline lens whose PLUS power is controlled by your ciliary muscles. For distance, your Crystalline lens is fully relaxed and has somewhere around +15 diopters. When you focus to read, your Ciliary Muscles squeeze the Crystalline lens to increase its PLUS power by the amount necessary to focus which depends on the distance to the object.
This will take a little thought to get your mind around, but if you are nearsighted, your lens system has too much PLUS for the distance from the lens system to your retina and you need MINUS lenses to neutralize some of that excess PLUS power. You ONLY have the ability to increase the PLUS power of your lens system. You have NO ability to reduce the PLUS power of your Crystalline lenses more that fully relaxed.
To try to keep your Ciliary Muscles and Crystalline lenses from getting in the act, the examiner will start with NOT ENOUGH MINUS or TOO MUCH PLUS (same thing) and gradually increase the MINUS one or two steps at a time, while reducing the size of the line you are asked to read. He will not tell you what power lens or what line you are looking at. Eventually, he will reach the 20/20 line and a lens power that lets you read it with no mistakes.
He will then follow the same procedure with your Left Eye.
When he has completed both eyes, he will open the shutters and you may see two images. This part of the test is to check your muscle balance using some prisms. He will probably ask you to tell him when the two images are aligned horizontally and then vertically. While the images are separated, you have an important check to make. Compare the sharpness of the two images. If they are not equally sharp, be sure and tell the Examiner which image is clearer. If there is a difference, he will likely reduce the sharpness of the clearest image until they match. The important thing at this point is that they match. That lack of sharpness will be corrected in the next phase with both eyes working together.
Next he will fuse the images so both eyes are working together and repeat the Sphere procedure by gradually increasing the MINUS or decreasing the PLUS until you see the smallest line of letters very clearly.
That pretty much completes the exam except for checking your near vision with a small chart about 14 to 16 inches from you.
Many people, who wear glasses, actually look forward to eye exams. Once you have become accustomed to having very good vision, you will probably find anything less, unacceptable. Many times, after the exam, it will be suggested that you get another exam some time in the future. Note that I used the word “suggested”. it is NOT a Command. If your detect a problem or if your vision seems uncomfortable, please don’t wait until the “suggested” date to seek an appointment to get your vision checked.
Please let us know about your exam and your glasses prescription.
GettingGlasses 07 Jan 2017, 11:58
Just got back from the appointment, and as I already knew I need glasses. The doctor seemed surprised that I did not already have glasses. It was so cool when the doctor put those big black glasses thing in front of me and I was able to see the letters on the wall. The glasses will be ready later today.
Soundmanpt 07 Jan 2017, 10:27
Nice to hear that you're finally getting your eyes examined. I assume that you might be rather young and you have been having a problem with convincing your parents that you think you need glasses? It seems that since glasses have become more popular in recent years that parents often think that their son or daughter is only wanting glasses because they are popular or because a friend at school recently got glasses. Anyway you seem quite certain that the result of your eye exam will have you wearing glasses in the near future. But now that you're about go for the exam you are becoming anxious about the exam. It's very true now that an eye exam can often find early signs of glaucoma as well as other health issues that you might have which may not even seem to connect to your eyes. Such things as diabetes and heart problems are a couple of things for example. But if you do have any of these things finding out now is better than finding out later. But most likely they will only find that you need glasses like millions of others. The full eye exam will only take around 40 to 50 minutes. Since these will be your first glasses and if your eyesight really does "suck" it's very possible that you will be wearing your glasses full time. So you're right in wanting to find the "perfect" pair that looks the very best on you. You didn't say if you're male or female but since you seem concerned about the looks of the glasses I am guessing that you might be a female. Guys don't often think about having their glasses look good. I'm sure that as soon as you come out from the exam that an optician will greet you and offer to help you choose your glasses. Trust this person. After a while you will probably have several frames that you really like and then it will be up to you as to which one you like the best.One tip I will suggest is since these will be your first glasses and for most there is a "getting used to your glasses" period. Dark full plastic frames often look nice but for many they are bothered by seeing so much of the frame in their line of vision. After a while of course you get used it and it no longer bothers you. But you may want to consider a semi-rimless frame where there is only frame across the top of your glasses and no frame on the sides or bottom to get in your view. I highly suggest that you be sure to ask for a copy of your prescription as well as your PD measurement before you leave the store. Now that your getting glasses you might want to get another pair or two and maybe even prescription sunglasses. Having your rx and PD will allow you to go on line and order glasses at much more inexpensive price. The one many of us favor in here is "zennioptical.com" they have several hundred for under $13.00 to choose from.
When you return form your eye exam please tell us how it went. And calm down you have nothing to be concerned about.
GettingGlasses 07 Jan 2017, 04:32
Finally getting my eyes checked after asking for years. My eyesight sucks, so I know I am going to need glasses. I am kind of anxious about the appointment. I mean I know I need glasses, but what if the doctor finds something else wrong with my eyes? Also I am so anxious about choosing my glasses. What if I won't be able to find one that looks good on me. It is so weird that I am so excited and anxious at the same time. It is all I can think about. How is the appointment? What happens? This is my first time going to the eye doctor.
Soundmanpt 24 Dec 2016, 11:06
Most people never really notices their eyesight is changing until it gets bad enough for them to notice, sometimes they are made aware of it by trying on a friends glasses and being surprised at how well they can see or being with a group of friends and being the only one unable to read a menu board or some other sign maybe. You may feel like you can see fine but if you weren't able to read the letters on the lower part of the eye chart then your not seeing fine. Letters are what make up words so if you couldn't see the smaller letters then you can't read words either like at school on the blackboard for example very well. What you are able to see is because you may manage to see a few letters of each word and then figure out what the word is even though you can't see some of the letters clearly. Getting your first glasses can be a bit scary because your afraid of what your friends are going to say when they see you wearing glasses. That's actually pretty normal, but I have a feeling that some of your friends already wear glasses and they had to go through it too when they got their glasses. Glasses are very common these days and all that is going to happen is that you're going to get lots of complements on how nice you look wearing glasses. Only someone very immature would ever tease you about wearing glasses and i'm sure it wouldn't be someone you call a friend. Like "Cactus Jack" said wear your glasses all the time for about the first 2 weeks and then decide if you still think you see fine without glasses or not. You're going to be seeing a lot more than just those few lines at the bottom of the eye chart. By the way haven't you heard that glasses have become a fashion accessory for many young ladies these days. You only need to go into a boutique such as Claire's to see the racks of fake glasses they have. After you have had your glasses for a few days come back and give an updated report about wearing glasses.
Cactus Jack 24 Dec 2016, 10:03
Many young people have a similar opinion as you, about your vision. Everyone thinks that their vision is just fine, because they have no frame of reference. Vision actually occurs in the brain, your eyes are merely biological cameras. You brain has the ability to correct what you "see" IF it knows what something is supposed to look like, but it takes a lot of energy and effort. Your brain can even create images with your eyes closed. Ever had a dream?
It is normal to be worried about getting glasses. Particularly about what other will say or think. Glasses are simply tools to help you see better. In some ways they are no different than wearing shoes, which are tools to keep the rocks from hurting your feet. The comments about your glasses, by others, will only last for 2 or 3 days, just like happens when you get new clothes or a new hair style.
I urge you to wear your glasses every hour you are awake for 2 weeks before you make a judgement about their benefits. Initially, you will think they have made your vision worse, but that is not really true. What will happen is that your brain will discover that your glasses are doing the extra work it was doing and it can use it abilities for other things.
I suspect that in a few weeks, you will change your mind and decide that seeing really well, is the best Christmas present, ever.
May I ask your age and if you know it, your prescription?
If you are curious about what your prescription means, we can help you with that.
Kala 24 Dec 2016, 09:33
I guess mom had a sudden urge to take her kids to an eye doctor, so she took me and my brothers in to get our eyes checked today. Turns out my youngest brother and I "need" glasses. I can see fine. I get by in school and everywhere else. The doctor was so rude. He was all like, "I am surprised Kala has not been having trouble in school. She has quite the need for glasses." I see fine. So what if I could not read all the way down to the bottom on that stupid chart. I was tierd, and have a mild cold. Anyways it is not like I amn going around looking at charts with ridiculously small print all time.
I really do not want glasses, especially not on Christmas Eve. What a way to ruin christmas.
Soundmanpt 18 Dec 2016, 15:19
Have you ever been coloring in a coloring book and you just had to go outside of the lines? Well by wearing glasses that are just a bit quirky that is exactly what you're doing and why not? You already enjoy wearing your glasses and in the past you have pretty much stayed in between the lines with your glasses. Remember you usually describe your glasses when you get new ones. They are always very nice and i'm sure probably look very nice on you but also very "inside the lines" glasses. I would not at all be surprised if these new glasses aren't your favorites very shortly. I can't wait to hear what all you're glasses wearing friends think of them. My guess is that you're sue to get many complements on them. I'm betting they are the most comfortable glasses you own?
I'm as ready as I am ever going to be for Christmas. I don't have any family living anymore so I really don't bother with Christmas. I stopped putting up a tree several years ago. But I don't want to be a "Bah-Hum-Bug" person either. For a number of years it bothered me to watch any Christmas movies, but in the last couple years I have started watching and enjoying them. But I am glad when January 2nd comes along.
Carrie 17 Dec 2016, 12:11
Soundmanpt thank you for your flattering comments. Yes, I am not fat but I do have what is known as a "muffin top" when I wear jeans and my breasts are a rather on the big side which makes me feel self-conscious somtimes in front of some men, especially ones I don't know. I have been wanting to get some round glasses for quite a while now and am really pleased to be able to get some at a good price. They are quite quirky for me as most of my frames have been fairly 'safe'.
I was given the impression at my last eye test that I now have my full prescription, but maybe I don't.
We are very much looking forward to Christmas and just about ready. Although the shop I work in isn't one of the really big ones it's still been busy and I've done extra shifts due to staff shortages. Are you ready for Christmas?
Soundmanpt 17 Dec 2016, 10:35
I really like your new glasses and I have a pretty good idea that they look really cute on you. Of course I am saying that based on how you have described yourself. Short with nice breasts, not skinny but not fat either, am I right? Anyway I can tell by looking at them that they should be very comfortable to wear. Very light weight. I just noticed that another on line site "eyebuydirect.com" was also doing a buy one get one free promotion, but I think that ended yesterday. Interesting hos similar the name is I wonder if they might be the same site but with a ULK home base? As much as you love wearing glasses I think getting a bit of a "glasses wardrobe" going is a fun idea.Even better when you can get your glasses at low cost. But until your eyes get stable and stop changing you still won't be able to really enlarge your collection too much. But it's still really nice to change glasses from day to day instead of wearing the same pair everyday. Glad to hear that Gemma is also planning on getting a pair or two as well. Even though she isn't into glasses nearly as much as you, she still needs her glasses full time so she should like being able to change her glasses from one day to the nest as well. Are you ladies ready for Christmas?
Carrie 17 Dec 2016, 07:49
These arrived in the post this week http://www.glassesdirect.co.uk/glasses/london-retro-sweeney/?prca=PRCA20130600&aspect=front and as you can get a second pair of glasses free I ordered one pair in silver and one in gold (I couldn't decide which colour to get so getting both for the price of one was great). I love them and they suit me so well! Gemma also loves them. She tried one of them on to see if they suited her. Obviously she couldn't see herself very well as our prescriptions are totally different so I took a photo of her. She was a little disappointed that they didn't suit her but might look for some different ones in the new year. Neither of us need new glasses but I want to expand my glasses wardrobe and Gemma is too, but by a smaller amount than me.