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I am going to take a shot at answering this OCT question, but before you read, please note that I am just an eye-patient and not an eye-doctor or a medical student. So, I can only partially read the OCT scans but not interpret them for you; [COLOR="Red"]for its interpretation, that is, whether certain OCT data is normal, good, or worrisome, you MUST see an eye-doctor or a retinal specialist[/COLOR].

What I write below can be all found from the internet and using good engineering common sense, and is what I have learnt on my own after my eye operations (retinal detachments). I am writing here because it is a good learning experience for me, and, perhaps, may be for others too who want to read their OCT scans; you may, perhaps, already know a good deal about what I write below.

First, some acronyms,
OCT = Optical Coherence Tomography (type of outpatient photography used to quickly find retinal cross-sections and retinal thickness distribution, etc.)
OD = Right eye (from patient's viewpoint), OS = Left eye
ILM = Inner Limiting Membrane (boundary between retina and the vitreous body - this is where the light falls first from the lens side; wiki has a good figure for the different retinal layers)
RPE = Retinal Pigment Epithelium (outermost surface of the retina which also partially nourishes it; it touches the rods and cones - the light-sensitive neurons)
N = Nasal (side), T = Temple (side)
S = Superior? (top-side), I = Inferior? (bottom-side)
ETDRS = Early Treatment Diabetic Retinopathy Study

So, basically, the two OTC charts you have linked principally show the state of the retina from the viewpoint of thickness, etc. (I will continue to the next post, otherwise it will be too long!)

vitcat2
[QUOTE=vitcat2;5320665]I am going to take a shot at answering this OCT question, but before you read, please note that I am just an eye-patient and not an eye-doctor or a medical student. So, I can only partially read the OCT scans but not interpret them for you; [COLOR="Red"]for its interpretation, that is, whether certain OCT data is normal, good, or worrisome, you MUST see an eye-doctor or a retinal specialist[/COLOR].

What I write below can be all found from the internet and using good engineering common sense, and is what I have learnt on my own after my eye operations (retinal detachments). I am writing here because it is a good learning experience for me, and, perhaps, may be for others too who want to read their OCT scans; you may, perhaps, already know a good deal about what I write below.

First, some acronyms,
OCT = Optical Coherence Tomography (type of outpatient photography used to quickly find retinal cross-sections and retinal thickness distribution, etc.)
OD = Right eye (from patient's viewpoint), OS = Left eye
ILM = Inner Limiting Membrane (boundary between retina and the vitreous body - this is where the light falls first from the lens side; wiki has a good figure for the different retinal layers)
RPE = Retinal Pigment Epithelium (outermost surface of the retina which also partially nourishes it; it touches the rods and cones - the light-sensitive neurons)
N = Nasal (side), T = Temple (side)
S = Superior? (top-side), I = Inferior? (bottom-side)
ETDRS = Early Treatment Diabetic Retinopathy Study

So, basically, the two OTC charts you have linked principally show the state of the retina from the viewpoint of thickness, etc. (I will continue to the next post, otherwise it will be too long!)

vitcat2[/QUOTE]

(Continuation from my previous post)

Consider the first chart for the right eye OD(R):

• It is as seen by the doctor or the machine since the yellow spot on the top left photo, which is the entrance of the optic nerve in the eye, is to the right, close to the nose side of the right eye

• The region of the area scanned is shown by the square in the top photos, and the locations of the retinal cross-sections, shown below them on the left side, is shown as at 64 and 256

• The middle left photo on the left side is the retinal cross-section going from the temple (T) side to the nose (N) side horizontally at location 64; and , the bottom left photo is the same going from the top side (S) to the bottom side (I) vertically at location 256 - both of which roughly cross the central portion called the macula, the center of which is called the fovea - which is, perhaps, the most important region and responsible for fine reading skills (like, sewing a needle, etc.)

o The depression in these two photos on the left side is where the "fovea" is located, and is surrounded by two "mounds," which is normal
o The different colors in these retinal cross-sections show the different layers of the retina: the topmost being the ILM and the bottom one being the RPE (I don't know exactly where the bottom one ends)
o If there is some sort of separation between these layers or some abnormality then this cross-section photo captures it well
o Also, if the ILM is not smooth then it may indicate "epi-retinal membrane," an extremely thin cellophane tape like substance which, I understand, is not normal, and may sometimes cause wigglyness or waviness in vision - [COLOR="red"]let the doctor interpret this! Please don't try to read too much into this yourself[/COLOR].

• The middle photo (the green circle: ETDRS) gives a contour plot of the thickness distribution between the ILM and the RPE in micro-meters (1 micro-meter = 1/1000 mm)

o green color indicates 5% to 95% (percentile), that is, "normal" thickness, I presume
o yellow indicates 1-5%, that is, slightly below the norm; if other colors appear, their percentile thickness distributions are given in the legend below it
o the other thickness metrics, like, average thickness, center thickness (foveal pit), is given in micro-meters, and the total volume of this cross-section is also given in cubic mm
o again, only the doctor can tell if it is just fine or not

• A 3d- colored surface picture of these two layers, ILM and RPE, are also given at the bottom right (I think, the locations are according to the color scale in the top right photo but I don't know where the reference 0 -datum is located)
o the depression in the ILM, like a volcano crater with its mounds, near the fovea is very clear in this photo; whereas, the RPE looks relatively smooth and flat

• The middle right photo is a shadowgram and I don't know what it indicates, but looks like it shows the arteries and veins on the surface of the retina, needed to nourish it, as well as the fovea at its center; it can capture retinal detachments, and scars, etc.


You can read the OCT scans of the [COLOR="Blue"]left [/COLOR]eye similarly in the next chart - what predominantly stands out to me are:

• the center photo which shows the retinal thickness distribution and has the 0-1% peach color at the bottom and seems quite thinner than the norm [COLOR="Red"](ask your doctor about it!)[/COLOR]
• also, the top left photo shows lots of black patches on the red color, as compared to your right eye [COLOR="red"](ask your doctor about it!)[/COLOR]


The third chart is a zoomed-in photo of the left eye at a slightly different location (59) from nose to temple - it shows all the retinal layers in a magnified way [COLOR="red"](ask your doctor if it is okay)[/COLOR]


The fourth chart is a zoomed-in photo of the right eye at a slightly different location (60) from nose to temple - it shows all the retinal layers in a magnified way [COLOR="Red"](ask your doctor if it is okay)[/COLOR]

[COLOR="Red"]The bottom line is that although you can READ some of the aspects of these charts now, you are not in a position to interpret them. Once again, PLEASE ASK YOUR DOCTOR TO INTERPRET THEM FOR YOU! [/COLOR] (especially, the left eye)

Hope this helps you and others too!

vitcat2





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