What are the blobs floating across my vision? Are frequent nosebleeds serious?

Unidentified floating objects

Unidentified floating objects

Q. I have recently begun to notice one or two tiny black objects drifting across my vision as I look forwards. They have appeared for no apparent reason. They are not there if I close my eyes, and I think they are coming from my left eye only, although I cannot be absolutely sure. I am still able to see and read normally, but they are rather distracting. Will they disappear as quickly as them arrived? Do I need to see the optician? Is any treatment necessary?

A. You are describing floaters. They are caused by a drying-out of the jelly-like substance (the vitreous humour) that fills the eyeball. Floaters appear when tiny clumps or strands of vitreous cast a shadow on the retina at the back of the eye. The vitreous has a tendency to get thicker with age, and this is why floaters are more common in older people. If you are getting large numbers of floaters, or if you notice flashes of light in your visual field, you need to get urgent attention from an eye specialist, as these are signs of retinal detachment. There is no cure or treatment for simple floaters, but people who have them usually find that they become less troublesome, probably because they unconsciously learn to disregard them.

In the blood

Q. A while ago, you wrote that people who get nosebleeds should not worry unless the nosebleeds are severe and frequent. I have been getting nosebleeds for about a year (I am 35 and otherwise healthy). A series of investigations has revealed that I have a condition called hereditary haemorrhagic telangiectasia (HHT). Apparently. this has been passed on from one of my parents, but as far as we can tell neither of my parents had this condition (both have now died from other causes). Is it possible that some other readers with nosebleeds actually have HHT?

A. HHT is a very rare genetic condition that can affect both men and women. It is usually inherited from one parent or the other, but it is possible that one of your parents carried the gene for the condition but never showed any obvious signs of it. People with HHT have unusually fragile blood vessels which can bleed at the slightest provocation. Sometimes they start bleeding spontaneously. The fragile blood vessels can occur in any part of the body. On the skin, they are particularly visible around the lips and on the face, where they look like small blood blisters. Because HHT is such a rare condition, you should aim to see a doctor who specialises in the condition. This may be a genetics specialist, or it may be someone who deals with blood-vessel problems. HHT can cause particular problems for women in pregnancy, and people with HHT often require special screening tests to look for unusual blood vessels in the lungs. If you are not already in touch with the Telangiectasia Self-Help Group, I suggest that you get in touch with them. Their web address is: www.telangiectasia.co.uk.

FInding the fit

Q. My brother-in-law, who is in his mid-eighties and wears a catheter, continuously has problems with urine bypassing it. During a recent visit by the district nurse, she told him that the reason this happened was because his urine was alkaline and she quoted pH values varying from 7 to 10 over a period of a few days. I would be grateful if you could tell me whether this is a reasonable explanation for the problem, whether the pH usually varies in this manner, and whether there is an underlying medical cause.

A. A catheter is a flexible tube that goes through the penis and into the bladder. At the bladder end of the tube, there is a small balloon that is inflated to prevent the catheter from falling out. The outer end of the tube is connected to a plastic bag that collects the urine which flows out of the bladder. If urine is leaking out, I doubt that this is anything to do with the pH or alkalinity of the urine. I can't think of any reason why urine which is alkaline is more likely to escape from the bladder than urine which is acidic. The leakage is more likely to be caused by a catheter which is the wrong size. If it is too small, urine will leak around it. I suggest that the next time the catheter is replaced, a larger size is tried. It may take some experimentation to find the correct size, but for the sake of your brother-in-law and those around him, it is worth the trouble.

Have your say: readers write

HM has personal experience of "white coat" hypertension:

I can confirm the "white coat" syndrome, but I think it fades away quite quickly during each visit to the doctor. My BP reading is always high on entering a surgery but I have found that, given enough time, it almost always falls to a satisfactory level - as I found when a cardiologist took my blood pressure four times at 15-minute intervals. As for self-measurement, I took my Omron RX-3 wrist machine to the doctor and he took my BP in the usual way after I had used the machine in front of him. He then recommended a particular way of holding it to countervail a "pessimistic" (ie over-high) reading. I was disappointed, though, to find that only one wrist machine (Braun) is given the "all clear" on the www.dableducational.com website.

Send your questions and suggestions to A Question of Health, 'The Independent', Independent House, 191 Marsh Wall, London E14 9RS; fax: 020-7005 2182; or e-mail: health@independent.co.uk. Dr Kavalier regrets that he is unable to respond personally