As an aside, thank you, for the comments and emails received with regard to my previous ‘Eyes’ posts. I know many readers have found them interesting and helpful.
When second and subsequent appointments are necessary at the hospital eye clinic the procedure may differ slightly as additional tests may have been requested by the Doctor. before you are seen again .
Part I referred to the Field of Vision test which may have been requested if pressures in the eyes appeared to be high or if there is a family history of glaucoma. In this case the patient may already have been tested by his/her own optician./ optometrist. The test used in my hospital is known as Automated Perimetry. This test evaluates your vision field by flashing random lights of different strength (generated by computer) in your peripheral vision field while your eyes are fixed on a source light straight ahead. The patient uses a button to indicate the presence of objects. There may be a blind spot if you fail to see objects in a certain portion of the visual field. This test requires the patient to be able to co-operate and concentrate and requires a certain amount of co ordination so is not suitable for everyone. There are other alternatives so don’t worry if there is a problem for you. I dislike this test because it appears to trigger my claustrophobia and makes my eyes water copiously.
A doctor I spoke to recently said that it was stressful because lights are shown which are outside the normal field of vision, and patients sense this is the case and feel anxious. because they have failed to register the flash. I don’t think it is ever taken as definitive in itself, – few tests are. It may be worth asking for it to be noted, however, if you have a headache or if your eyes are affected by hay fever or sinus problems. The Doctor will give you the result during your consultation.
It is also routine for an OCT scan to be requested. I have one almost every time I visit the eye clinic. OCT means Optical Coherence Tomography. This is a wonderful tool with many applications. It is a way of photographing cross sections of the retina in 3D, when used in ophthalmics. As well as its diagnostic uses it is also used to measure the success of various procedures and even indicate hazards which might occur in surgery. It can identify the areas where sub retinal fluid is present which means that injections or laser may be targeted more accurately in maculopathy and macular oedema.
The patient is asked to look into the camera. .Then it is just a matter of keeping the eyes wide open and not blinking while focusing on a central point for a few seconds. There is with the older machines a brief flash of light at the end but nothing else to disturb or alarm. Wheelchair users can remain in their wheelchairs for the scan. The results will be available on computer screens within minutes.
When I first began having regular OCT scans they were carried out by a skilled and experienced biometrist, then, a few years ago nurses were trained on the procedure. Some are excellent and there are no problems, but others find it challenging. Unless the image is clear it is useless. Occasionally the scan has to be repeated. The operator can examine the finished product and decide it is not good enough or the equipment senses that an error has occurred. I am so used to it all that I can tell with some accuracy when a retake is going to be necessary. It is usually because the focus wasn’t correct to begin with.
While searching for images I came across this in Netscape the American Ophthalmology magazine. Link here to article.
Also the images below show the scan in the top picture macular oedema while that underneath shows normal.
A very little experience, allows the patient to correlate the inconsistencies in vision apparent when tested on the standard eye chart with the images shown on the scans. Overlapping letters sloping and missing letters can all be matched to the irregularities on the OCT. I think my consultant is still trying to work out how I always know which eye is shown on the screen at any one time. I can only imagine the improvement in diagnosis and treatment which this amazing piece of technology has made possible while being so comfortable and non-invasive for the patient.
FUNDUS FLUORESCEIN ANGIOGRAPHY
The final test which may be advised for patients with diabetic eye disease is Fundus Fluorescein Angiogram commonly known as FFA [of course.] This procedure or the suggestion of it has been the cause of more anguish in my correspondence than any other. For a start to most people an angiogram means a coronary angiogram, they will never have heard it associated with eye problems. It is used to obtain more information about the blood vessels in the retina. It will show if there is leakage or bleeding and where treatment, if necessary, should be targeted. Patients – especially the newly diagnosed, are often terrified by the consent form they are asked to sign and the warnings they are given. The fact is that the dye used in this procedure, the fluorescein, yellow dye is not licensed to be used in this procedure, and was not developed for this purpose. It is however commonly used and very effective. The use of unlicensed substances is very common and something for which we should all be grateful. The hospital is obliged to tell patients of this and also to advise them of the risks involved in this procedure, for insurance reasons amongst others. Many people feel slightly nauseous for a few seconds after the injection, others may experience some slight allergic reaction on their skin afterwards, and very rarely, – one in about 25,000 patients will experience a more severe reaction which will be dealt with immediately by the emergency team. The benefits of the procedure are considered to far outweigh any risk.
I have had 3 angiograms and am still here to tell the tale! Before the procedure begins you will have your blood pressure checked and pupils dilated. You will be asked about allergies. There is a particular concern about iodine allergy so a bad reaction to shellfish would be something which must be disclosed. After your pupils have been dilated a cannula will be placed in a vein in your arm. You will be seated in front of a camera with chin and forehead rest and a series of rapid photographs will be taken. The dye is then injected via the cannula and this is the point at which nausea may be felt. I have only experienced this feeling once. On the other two occasions the officiating nurse believed that injecting the dye very slowly prevents nausea and this seemed to work.
More photos are then taken accompanied by more flashing lights, and after a while you will be allowed to rest for a few minutes. Then the final photos are taken. It is normal for the cannula, – now disconnected from the dye to be left in the arm until you are discharged, after about 30 minutes to allow you to recover and to check that no side effects occur. Some patients may need antihistamines for rash or redness at the cannula site. Tea and coffee is supplied in my clinic.
For 24 – 48 hours afterwards your skin and urine may appear orange or yellow, this is harmless and nothing to worry about. Drinking a lot of water should help to get rid of the dye. Then you are free to go. The doctor will generally discuss the results with you on your next visit. The only problem I have experienced apart from momentary nausea is with the insertion of the cannula. This very much depends upon the nurse. I have been very fortunate in having the same excellent nurse do this twice and it was totally painless. It is after all a very small cannula and a very fine needle used in this procedure. On one occasion a male nurse had seven tries in one arm and four in the other and was unable to insert the needle. It was excruciatingly painful. Having had a much larger cannula inserted by a paramedic on one occasion and a doctor on another I knew that the individual must be inept. Eventually I suggested that they try the wrist and this was successful. He had been suggesting a direct injection of the dye without the cannula but I was reluctant because I had no confidence in him by this time. I was later told that it is never a good idea to allow multiple attempts at inserting a cannula, or at drawing blood, as permanent and serious damage could be done.
I can‘t help but feel that it is the HCPs who ought to be aware of this and that the onus should not lie with the patient. In fact staff should be properly trained and proficient before being allowed to practice upon patients. I have heard from others that my experience is, by no means unusual or uncommon. If the cannula is not inserted properly and the dye escapes into the surrounding area it can cause burning which, while not serious, should be avoided if possible.
I have a great deal of sympathy for anyone asked to have an FFA shortly after diagnosis, I can well imagine the anxiety this would cause. I have had 3 FFAs in 3 years but this is unusual. It depends on the individual eye condition.
As with many tests and procedures the anticipation is worse than the experience. A newly diagnosed person may feel that this is only the beginning of a series of invasive tests but this is not the case at all. If you are a new patient and FFA is recommended it will certainly help in diagnosis and to pinpoint areas where treatment may be necessary. Most hospitals produce their own fact-sheets about these procedures, but these vary a great deal, and can be misleading. I would advise anyone who is at all concerned to look at the information provided by several different hospitals which are usually available online in PDFs. This provides a fuller picture. Your hospital will always answer questions, but it is worthwhile doing your own research as it is very easy to misunderstand and not all hospital staff can be familiar with every procedure. Confusing and sometimes slightly uncomfortable as these tests may be it is worth while reflecting that not so long ago none of them were available and diagnosis and treatment would not have been possible until it was too late. It is much rarer for people to lose their sight completely these days and many new treatments are in the pipeline.
Next time I would like to share my experience of laser and eye injections .in the hope that they will be of interest and use to others. These are matters which worry many diagnosed with retinopathy