Instructions for techs on the OCT


In regards to our talking about optical coherence tomography ( OCT ) last week, I would encourage you to read the entire OCT manual which is available online. I know it can be rather daunting but if you would read 3 pages each day and try to make sense of what the book is describing then over several months you would get through the entire manual. Mark Mitchell thought he had the manual in paper form if that would be better. I know you can be quite busy but I think some days you do have the time to read the manual. It's probably fairly boring but a few pages daily is manageable.

You have two useful ( helpful ) programs with the OCT. #1. Is to look at the macula and determine macular thickness / configuation, etc. compared to the other eye. #2. The other quite useful program is the evaluation of the retinal nerve fiber layer ( RNFL ) with laser polarimetry which is that green, yellow, red diagram that we looked at together, that compares the retinal nerve fiber layer ( RNFL ) thickness of the two eyes. With glaucoma the RNFL thickness decreases. This is a quite useful test for patients that have glaucoma or may have glaucoma ( glaucoma suspect ). RNFL measurements and the optic disc photos are quite useful for following glaucoma patients as neither test depends on the patients' answers such as with visual field testing.

There is a large amount of useful information on the search engines ( Google, etc. ) about OCT. Through BING there is an OCT atlas with a lot of examples of OCT problems --- epiretinal membrane, vitreous retinal traction, pigment epithelial detachment, macular hole, central serous retinopathy, etc. Would encourage you to have a look. Also ? You -Tube.

You should be able to obtain good quality imagines of the macular area on a regular basis. That foveal depression in the macular area should be readily obtainable in most normal eyes.

As with retinal photos, having the patient forehead up on the support is good. Then ask the patient to blink several times and have them " hold still " is how most retinal photographers take the retinal photos / OCT. By having the patient blink several times, you are ensuring a full thickness ( normal thickness ) evenly distributed precorneal tear film. When the tear film starts breaking up, you get dry spots on the cornea and the retinal image ( photo ) deteriorates. The key is to have the patient blink several times before asking them to hold still ( " blink, blink, blink --- OK, look straight ahead / don't blink " ). If you do this the retinal imagines ( quality ) would probably improve.

If you are doing retinal screening photos, you should not have the patient make an additional trip to get the results of the photos. The break down should be a totally normal retinal photo or some retinal changes ( abnormality ) in which case that patient should be referred to Dra. Perez or someone. If the photos are normal the patient should be told that, otherwise referred on.

Lastly I would encourage you to give every diabetic patient you photo a copy ( ? orange sheet ) of the diabetic handout we ( Dr. Schwab, Carla, etc. ) produced several years ago. Giving them the sheet in both English and Spanish is best. Patients like getting colored handouts. You spending 5 -10 minutes talking to every diabetic patients about their diabetes and control is probably the best thing you can do for these diabetic patients. All things considered, that's probably more important than the retinal photos. There is a lot of good information about diabetes through the search engines --- diabetes, diabetes control, diabetic diet, etc.

Many of our diabetic patients are not well controlled. This is true all over the world. Although many of them have heard it previously, diabetic education / training is again probably the best thing you can do for our diabetic patients. You can also tell them about the Belize Diabetes Association ( support group ) and also about the nutrition ( dietician ) clinic at the KHMH. Diabetic retinopathy unfortunately has become ( increasing ) a leading cause of visual loss worldwide.

However many diabetic patients do quite well with no eye changes, etc. for many years. The key is to keep the diabetes ( glucose ) under control as well as the blood pressure and the cholesterol / triglyceride. Uncontrolled hypertension / hyperlipidemia is big time harmful ( aggravates ) to diabetics.

A strong indicator ( marker ) of other systemic diabetic problems is the presence of diabetic retinopathy. In other words, if our patients show any diabetic retinopathy changes then it is quite likely they already have some renal damage, peripheral vascular insufficiency, peripheral nerve damage, etc. If your glucose is not controlled you are much more likely to have a stroke or heart attack ( MI ). That's why it is important for all of us to try to educate our diabetic patients, so they don't end up with renal failure or having a leg cut off. That's what we are trying to prevent. You ( the retinal photographers ) are in the right position to educate these diabetic patients. You don't need to scare them, but you need to tell them the truth. It's not just about the eyes.

Hope some of this is helpful.

Peace, Baxter McLendon

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