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Hi all,
The following is an excerpt from a long piece I am writing about computer use and dry eye. A more complete post will be made in a few more weeks.
Once you’ve scheduled enough appointments (and you won’t know if you’ve scheduled “enough” until you’ve found a doctor that you like), it’s time to take your visits. Selecting a doctor is kind of like dating – you’ll have to meet a bunch of candidates to know which one is best for you. And like dating, you’re not obligated to “marry” the first one you meet. Or the second, or the third, and so on.
Before the Visit
Before your appointment, you should do a couple things to make sure your appointment goes better:
Patient Questionnaires
One way that doctors measure and track the severity of a patient’s symptoms is by having the patient fill out patient questionnaires. These questionnaires may consist of many questions, including:
Tests
At both your initial visit and follow-up visits, your doctor will (or at least SHOULD) perform a battery of tests on you. Don’t expect a single doctor to do all of these tests on you – but a good doctor should do a lot of them.
Personally, the more tests a doctor does on me, the more confident I feel in his diagnosis. And if a doctor doesn’t take at least ONE image of your eye (e.g., meibography or confocal microscopy), then that doctor probably isn’t worth keeping.
Tests for General Eye Health
Two tests your doctor will do for general eye health are a vision test and eye pressure test.
Vision Test
One of the first things the doctor (or his assistant) will do is to check your visual acuity (i.e., can you see 20/20). Thus, you should bring any vision-correcting glasses or contact lenses to this appointment.
Eye Pressure
Taking steroid drops too frequently increases your intraocular (inner eye) pressure. Chronically high eye pressure increases your risk of glaucoma, a condition which causes blurry vision and may eventually lead to loss of vision. If you take any steroid drops at all (and even if you don’t), it’s a good idea to get this checked. You can take steps to lowering your eye pressure (including diet and exercise), but it’s best to do this before glaucoma sets in.
Tests for Aqueous Deficiency
There are a few tests for aqueous tear deficiency, but the gold standard is the Schirmer test since it is a direct measure of how many tears you are producing.
Schirmer Test
There are two versions of the Schirmer test, but both are very similar to each other. In a Schirmer test, a small strip of filter paper is placed on top of the lower eyelid and the patient is asked to close his eyes. While the eyes are closed, tears produced will either drain through the lacrimal ducts or be absorbed through the filter paper. After 5 minutes, the patient opens his eyes and the doctor measures the length of paper (in millimeters) that is soaked by the tears. Generally speaking, anything above 15 mm is considered normal, whereas anything below 15 mm is considered aqueous deficient.
In a Schirmer I test, anesthetic drops are put in the eyes before the test in order to prevent reflex tears from being generated (due to irritation from the filter paper). Thus, a Schirmer I test measures basal tear secretion only.
In a Schirmer II test, anesthetic is NOT used. Therefore, reflex tears are produced and a Schirmer II measures basal tear production PLUS reflex tear production. One can expect your values from a Schirmer II test to be higher than your values from a Schirmer I test.
Corneal Staining
To gauge general eye health, a doctor will put lissamine green drops into the eyes and examine them through a slit lamp (a microscope an eye doctor uses to look at your eyes up close). Areas of the eye that are damaged will appear different than the normal, healthy parts of the eye. Although many things may cause cells to be damaged (e.g., poor-fitting contact lenses), in the case of aqueous deficiency the cause is not enough tears getting to a certain area of the eye.
Confocal Microscopy
A confocal microscope, or HRT (Heidelberg Retina Tomograph), is a device used to take high-resolution images of the corneal nerves. It is a somewhat rare device that you probably won’t find at your average doctor’s office. Below is an example of an image taken with a confocal microscope.
With HRT, a doctor can determine the quality and quantity of nerves in your eye. Since nerves are critical for tear production, nerves that have been damaged aren’t helping to produce tears. Only when those nerves have been repaired can tear production increase. A patient who has many damaged nerves is diagnosed with corneal neuropathy, and may have eyes that feel gritty when blinking.
Tests for Meibomian Gland Dysfunction
The following are common tests performed to diagnose MGD. The gold standard here is meibography, which provides a detailed view of the meibomian glands.
Meibography
Meibography are images of the meibomian glands taken using an infrared camera. These images can be taken with a LipiView or LipiScan device, or other comparable IR imager. Your doctor will flip each of your four lids in order to take the pictures. An example image is shown below – the meibomian glands are the tube-like structures in the lid.
As the saying goes, “a picture is worth a thousand words,” and this is certainly true for meibography. A meibography image can reveal many things about your glands, including:
Using the images, the doctor will “grade” your meibomian glands on a scale from 0 to 4, where 0 means your glands are completely normal and 4 means virtually all of your glands have died. The below picture shows MGD progressing from “mild” to “severe.” Any area which appears empty of glands (where there would normally be a gland) is a gland that has dropped out.
Meibomian Gland Production Count
In addition to meibography, one other way of measuring meibomian gland health is to count the number of glands that are producing oil. The doctor does this by pressing against your lids with either a special tool (looks like a USB flash drive) or their own fingers. By pressing against different parts of the lid, they can get an idea of the total number of oil-producing lids.
Blink Analysis
If the doctor has a LipiScan or Lipiview machine, he can also determine how often you blink as well as how well you blink. Partial blinking (when the upper lid doesn’t completely meet the lower lid) is a potential red flag for MGD.
Tests for Both Aqueous Deficiency and Meibomian Gland Dysfunction
Some tests may not look for aqueous deficiency or MGD specifically, but they may signal a dry eye problem nonetheless. Here are some examples of those tests.
Tear Osmolarity
A person without dry eye has a normal “osmolarity” (saltiness) to their tears. As dry eye worsens and the quality of your tear film decreases, your tears get higher and higher osmolarity. This high osmolarity causes cell death at the surface of your eye.
When a doctor does a tear osmolarity test, he will take a small sample of your tears and run it through a machine to calculate its osmolarity. The following is an approximate severity scale for dry eye based on the osmolarity of the tear film:
Aqueous deficiency almost certainly causes tear osmolarity to increase. However, it is not known whether meibomian gland dysfunction increases tear osmolarity – some studies have not shown a clear link between MGD and tear osmolarity. Thus, a high tear osmolarity may only indicate aqueous deficiency as opposed to meibomian gland dysfunction.
Tear Break-Up Time (TBUT)
A tear break-up time test measures how long it takes for your tear film to develop a dry spot after blinking. A doctor puts a fluorescein drop in your eyes, tells you to blink, and then counts the number of seconds until a dry spot appears on your eye. Anything less than 10 seconds is considered to be abnormal and indicative of dry eye.
Since your break-up time depends on both the thickness of the oil layer as well as the thickness of the aqueous layer, a TBUT test will not tell you if you have specifically aqueous deficiency or meibomian gland dysfunction; instead, think of it as a test to measure how “bad” your dry eye is.
A Diagnostic Checklist
The following is a checklist of all the tests that were mentioned above. I encourage you to print out this checklist (or make one of your own), and mark off the tests that are done while they are performed on you. The tests that have asterisks (*) next to their name I consider to be essential tests. If your doctor skips one of those, that’s a red flag for me.
Evaluating Your Doctor As He Evaluates You
While you’re primarily at the doctor’s office to seek an evaluation and second (or third or fourth) opinion, you should also be judging the doctor as “the one” to treat you regularly. In addition using the diagnostic checklist printed above, you should also consider the following:
The following is an excerpt from a long piece I am writing about computer use and dry eye. A more complete post will be made in a few more weeks.
Once you’ve scheduled enough appointments (and you won’t know if you’ve scheduled “enough” until you’ve found a doctor that you like), it’s time to take your visits. Selecting a doctor is kind of like dating – you’ll have to meet a bunch of candidates to know which one is best for you. And like dating, you’re not obligated to “marry” the first one you meet. Or the second, or the third, and so on.
Before the Visit
Before your appointment, you should do a couple things to make sure your appointment goes better:
- Bring a list of prescriptions and eye drops you currently use. This will really help the doctor understand what might be working for you, and what other things you still need to try.
- Write down a list of questions to ask the doctor. You’ll no doubt have questions to ask the doctor before you come in, so write them down before you forget any of them. You can also add to this list while you’re at the office, if any questions arise there.
Patient Questionnaires
One way that doctors measure and track the severity of a patient’s symptoms is by having the patient fill out patient questionnaires. These questionnaires may consist of many questions, including:
- What are your current symptoms? Are you having pain, sensitivity to light, grittiness, burning sensation, excessive tearing, etc.?
- Rate your pain on a scale from 0-10 over the last 24 hours. Rate your pain over the last 2 weeks.
- How much worse are your symptoms in an air-conditioned building? How much worse are they during very windy days?
- How much has your dry eye interfered with your ability to use a computer? How much has it interfered with your ability to read? How much has it interfered with your day-to-day activities?
- (For follow-up visits) How much have your symptoms improved since the last visit?
Tests
At both your initial visit and follow-up visits, your doctor will (or at least SHOULD) perform a battery of tests on you. Don’t expect a single doctor to do all of these tests on you – but a good doctor should do a lot of them.
Personally, the more tests a doctor does on me, the more confident I feel in his diagnosis. And if a doctor doesn’t take at least ONE image of your eye (e.g., meibography or confocal microscopy), then that doctor probably isn’t worth keeping.
Tests for General Eye Health
Two tests your doctor will do for general eye health are a vision test and eye pressure test.
Vision Test
One of the first things the doctor (or his assistant) will do is to check your visual acuity (i.e., can you see 20/20). Thus, you should bring any vision-correcting glasses or contact lenses to this appointment.
Eye Pressure
Taking steroid drops too frequently increases your intraocular (inner eye) pressure. Chronically high eye pressure increases your risk of glaucoma, a condition which causes blurry vision and may eventually lead to loss of vision. If you take any steroid drops at all (and even if you don’t), it’s a good idea to get this checked. You can take steps to lowering your eye pressure (including diet and exercise), but it’s best to do this before glaucoma sets in.
Tests for Aqueous Deficiency
There are a few tests for aqueous tear deficiency, but the gold standard is the Schirmer test since it is a direct measure of how many tears you are producing.
Schirmer Test
There are two versions of the Schirmer test, but both are very similar to each other. In a Schirmer test, a small strip of filter paper is placed on top of the lower eyelid and the patient is asked to close his eyes. While the eyes are closed, tears produced will either drain through the lacrimal ducts or be absorbed through the filter paper. After 5 minutes, the patient opens his eyes and the doctor measures the length of paper (in millimeters) that is soaked by the tears. Generally speaking, anything above 15 mm is considered normal, whereas anything below 15 mm is considered aqueous deficient.
In a Schirmer I test, anesthetic drops are put in the eyes before the test in order to prevent reflex tears from being generated (due to irritation from the filter paper). Thus, a Schirmer I test measures basal tear secretion only.
In a Schirmer II test, anesthetic is NOT used. Therefore, reflex tears are produced and a Schirmer II measures basal tear production PLUS reflex tear production. One can expect your values from a Schirmer II test to be higher than your values from a Schirmer I test.
Corneal Staining
To gauge general eye health, a doctor will put lissamine green drops into the eyes and examine them through a slit lamp (a microscope an eye doctor uses to look at your eyes up close). Areas of the eye that are damaged will appear different than the normal, healthy parts of the eye. Although many things may cause cells to be damaged (e.g., poor-fitting contact lenses), in the case of aqueous deficiency the cause is not enough tears getting to a certain area of the eye.
Confocal Microscopy
A confocal microscope, or HRT (Heidelberg Retina Tomograph), is a device used to take high-resolution images of the corneal nerves. It is a somewhat rare device that you probably won’t find at your average doctor’s office. Below is an example of an image taken with a confocal microscope.
With HRT, a doctor can determine the quality and quantity of nerves in your eye. Since nerves are critical for tear production, nerves that have been damaged aren’t helping to produce tears. Only when those nerves have been repaired can tear production increase. A patient who has many damaged nerves is diagnosed with corneal neuropathy, and may have eyes that feel gritty when blinking.
Tests for Meibomian Gland Dysfunction
The following are common tests performed to diagnose MGD. The gold standard here is meibography, which provides a detailed view of the meibomian glands.
Meibography
Meibography are images of the meibomian glands taken using an infrared camera. These images can be taken with a LipiView or LipiScan device, or other comparable IR imager. Your doctor will flip each of your four lids in order to take the pictures. An example image is shown below – the meibomian glands are the tube-like structures in the lid.
As the saying goes, “a picture is worth a thousand words,” and this is certainly true for meibography. A meibography image can reveal many things about your glands, including:
- How many glands there are in the lid
- How much dropout (gland disappearance) there is
- If there is any scar tissue blocking your glands (very important to know before doing IPL or Lipiflow)
Using the images, the doctor will “grade” your meibomian glands on a scale from 0 to 4, where 0 means your glands are completely normal and 4 means virtually all of your glands have died. The below picture shows MGD progressing from “mild” to “severe.” Any area which appears empty of glands (where there would normally be a gland) is a gland that has dropped out.
Meibomian Gland Production Count
In addition to meibography, one other way of measuring meibomian gland health is to count the number of glands that are producing oil. The doctor does this by pressing against your lids with either a special tool (looks like a USB flash drive) or their own fingers. By pressing against different parts of the lid, they can get an idea of the total number of oil-producing lids.
Blink Analysis
If the doctor has a LipiScan or Lipiview machine, he can also determine how often you blink as well as how well you blink. Partial blinking (when the upper lid doesn’t completely meet the lower lid) is a potential red flag for MGD.
Tests for Both Aqueous Deficiency and Meibomian Gland Dysfunction
Some tests may not look for aqueous deficiency or MGD specifically, but they may signal a dry eye problem nonetheless. Here are some examples of those tests.
Tear Osmolarity
A person without dry eye has a normal “osmolarity” (saltiness) to their tears. As dry eye worsens and the quality of your tear film decreases, your tears get higher and higher osmolarity. This high osmolarity causes cell death at the surface of your eye.
When a doctor does a tear osmolarity test, he will take a small sample of your tears and run it through a machine to calculate its osmolarity. The following is an approximate severity scale for dry eye based on the osmolarity of the tear film:
- Less than 300 - Normal
- Between 300 and 320 - Mild
- Between 320 and 340 - Moderate
- Greater than 340 – Severe
Aqueous deficiency almost certainly causes tear osmolarity to increase. However, it is not known whether meibomian gland dysfunction increases tear osmolarity – some studies have not shown a clear link between MGD and tear osmolarity. Thus, a high tear osmolarity may only indicate aqueous deficiency as opposed to meibomian gland dysfunction.
Tear Break-Up Time (TBUT)
A tear break-up time test measures how long it takes for your tear film to develop a dry spot after blinking. A doctor puts a fluorescein drop in your eyes, tells you to blink, and then counts the number of seconds until a dry spot appears on your eye. Anything less than 10 seconds is considered to be abnormal and indicative of dry eye.
Since your break-up time depends on both the thickness of the oil layer as well as the thickness of the aqueous layer, a TBUT test will not tell you if you have specifically aqueous deficiency or meibomian gland dysfunction; instead, think of it as a test to measure how “bad” your dry eye is.
A Diagnostic Checklist
The following is a checklist of all the tests that were mentioned above. I encourage you to print out this checklist (or make one of your own), and mark off the tests that are done while they are performed on you. The tests that have asterisks (*) next to their name I consider to be essential tests. If your doctor skips one of those, that’s a red flag for me.
| Test | Done? |
| Vision* | |
| Eye Pressure* | |
| Schirmer* | |
| Ocular Staining* | |
| Confocal Microscopy | |
| Meibography* | |
| Meibomian Gland Production Count | |
| Blink Analysis | |
| Tear Osmolarity | |
| Tear Break-Up Time* |
While you’re primarily at the doctor’s office to seek an evaluation and second (or third or fourth) opinion, you should also be judging the doctor as “the one” to treat you regularly. In addition using the diagnostic checklist printed above, you should also consider the following:
- General temperament – is he easy to be around, or does he seem aloof and unconcerned?
- Patience – does the doctor seem to be in a hurry? Is he willing to answer any and all of the questions you prepared to ask as well as any others that might arise?
- Knowledge – does the doctor seem to be very knowledgeable about dry eye? It’s a bad sign if you know more than the doctor just by reading this post.
- Follow-up appointments – is it easy to make follow-up appointments, or does he take so many patients that follow-up appointments are hard to schedule?
- Location – Is the doctor nearby, or do you have to fly across the country to see him? Note that I think this is probably least important when considering a doctor. IMO, it’s worth it to travel far for a great doctor.
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