If you were going blind, would you want to know?

My friend may have a genetic trait that will rob her of her sight: Should she get tested?

Published July 6, 2005 7:41PM (EDT)

Hi ,Cary --

A close friend of mine told me today that there is a 50 percent chance she will go blind.

I didn't quite know what to do with this information, and I don't think she does either. So I thought I'd ask you.

Last weekend, my friend's mother told her that the cause of her father's declining eyesight had finally been discovered. He suffers from a rare genetic defect that causes progressive blindness. While he won't go completely blind, he has lost the ability to read and see details, and it will get worse. His father before him went colorblind, but he died before it progressed.

The genetic trait is dominant, and there is a 50 percent chance my friend has it. If she does, it will be expressed. If she has it, there is a 50 percent chance she will pass it on to her children. She's 25 and has perfect 20/20 vision. She loves colors, loves reading, loves details: Her job is as a paginator at a newspaper where the details are paramount. She's a vibrant, clever person whom others are naturally drawn to, but this news has cast a cloud over her.

The degradation of her father's vision didn't start until early middle age, so my friend has some time to think about this. Should she get tested and possibly find out she'll go blind later in life? Should she wait and risk worrying about it for years when in fact she doesn't have the trait? And if she has it, how does she live with the knowledge that she will someday lose her vision?

How does anyone respond to news like this? All I could tell her was that with medicine these days, who knows what we'll be able to accomplish by the time her vision theoretically starts to go. (There is no treatment currently available.)

I also told her we'd go get a drink.

Thanks for any perspective you can offer.

A Friend

Dear Friend,

I would choose to get tested and find out whether I have the genetic trait. I would choose to know my chances. I'm not saying I would want to know my chances. It's not something one necessarily wants. But I would choose to know them because of the way the problem stacks up logically:

At present, she does not know whether she has it or not. Nevertheless, she is worried. Without being tested there is a 100 percent chance that she will continue to be worried, off and on, for many years. If she chooses to get tested, the chances that she will continue to be worried in that same way drop to 50 percent. At the same time, even if she finds out that she has the trait, the quality of her worrying improves; she will have something tangible to worry about. She gains an idea she can start getting used to.

I prefer to worry about tangible things, things we can take action about. I think most people do better with that kind of worrying; it has a less corrosive effect. I think that is why, for instance, when someone disappears, we want to know where the body is. We like to know. It's better to know. Knowing allows us to construct more comforting fictions.

So how does one live with the knowledge that she will someday lose her vision? One lives with it, I suppose, as one lives with the certainty of eventual decay, old age and death. At 25 it is hard to imagine these things; at 50 it becomes easier; by 75 one really gets to know this decay, as one grows closer to the inevitable end. At 25 one still remembers the nearly inexhaustible power of adolescence. One still uses that as a frame of reference. If she has this trait, by the time she has approached the age when it will likely express itself, she will have found ways to accommodate this knowledge -- if she knows it is approaching. If she does not, she may have done much worrying but perhaps little preparation: Why prepare when you don't know for sure what's coming? That is another reason I think she should go ahead and get tested.

Also, as you say, "with medicine these days, who knows what we'll be able to accomplish by the time her vision theoretically starts to go?" Indeed, if she finds she has the trait, perhaps in some way she can not only benefit from an eventual cure but also participate in the search for it. Researchers may need the help of people with the trait to test the effectiveness of experimental cures. There may be a host of things one can do to stave off the onset of its effects.

There is, finally, a more abstract, less practical reason: Know thyself. Literally. Know everything about thyself. Know thy diseases and know thy fears; know thy self-deceptions and thy sins; know thy weak bones and thy strong bones, thy capacities and thy limits; know thy neck stiffness, thy sleep requirements, thy food sensitivities, thy secret hatreds and biases, thy fetishes, thy body types, thy terrors and delights. Know thyself. Know everything. Turn away from nothing. Know it all.

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