DEAR DR. ROACH: I am an 82-year-old woman who was diagnosed with glaucoma about three years ago. I have been taking latanoprost eye drops at bedtime since then.

A glaucoma specialist in my health maintenance organization recently recommended that I take salt tablets to raise my blood pressure (usually 115-120/60-70 mm Hg) to at least 130/70 mm Hg to get a better blood supply to my retina.

My regular physician says that this higher blood pressure is not recommended for cardiovascular health. Which doctor should I listen to?

— J.M.

ANSWER: Although your glaucoma specialist is correct that very low blood pressure can cause low blood flow to the retina, I disagree with the advice for salt tablets. A blood pressure of 115-120 mm Hg is just about optimal for a person in their 80s (and for younger people, too).

It is true than many years ago (back in the 1910s), physicians used to think that higher blood pressure was “essential” to get blood flow to the vital organs. But this thinking is long gone, even if the terminology (“essential hypertension”) is still sometimes used.

Raising the blood pressure does not protect the retina in people with glaucoma. Unless your ophthalmologist is aware of something that I am not, I disagree with this advice.

DEAR DR. ROACH: I’m writing in response to a recent column on Do Not Resuscitate (DNR) orders in advanced directives. I would note that performing CPR on an 80-year-old person, regardless of how healthy the person is, is likely going to break multiple ribs and possibly the sternum as you do compressions.

There is also a chance of puncturing a lung with a broken rib, depending on how long the code drags on. I’m a nurse; I’ve done CPR many times, and I’ve cringed at every crunch of bones I’ve heard as I pushed. Recovery from this may not ever be possible, depending on what caused the arrest. Bones heal slowly in the elderly.

You didn’t discuss the survival rates of CPR inhospital versus out of hospital; obviously, the survival rate is much lower if an arrest happens out in public, usually because there is a delay in starting CPR. You also didn’t discuss the possibility of neurological damage and decline with prolonged CPR. This can be exacerbated in older people due to the normal brain changes that happen with age, which are then affected by the decreased blood flow during cardiac arrest.

• P.M., RN