My mum had her eyes tested this week and was told her cataracts are likely to prevent her driving altogether within 2 years. Her father had cataracts; is there a genetic predisposition and around what age are cataracts likely to appear?

She was also told that surgery would likely result in her no longer needing glasses at all. She’s still fairly young (mid 60s). Does cataract surgery have long-lasting effects or is it only effective for a relatively short time? For people who do have to relinquish driving, what’s the average age for doing so due to failing eyesight?

And for mr buffy: I was watching Bondi Rescue where two people were pulled unresponsive and unconscious from the water. One died, but the other was resuscitated. The resus patient was attended by paramedics who put her “into an induced coma” for transportation to the hospital. I wasn’t aware that paramedics could do this and am wondering under what circumstances they would consider implementing the procedure?

Bump.

Divine Angel said:

My mum had her eyes tested this week and was told her cataracts are likely to prevent her driving altogether within 2 years. Her father had cataracts; is there a genetic predisposition and around what age are cataracts likely to appear?

She was also told that surgery would likely result in her no longer needing glasses at all. She’s still fairly young (mid 60s). Does cataract surgery have long-lasting effects or is it only effective for a relatively short time? For people who do have to relinquish driving, what’s the average age for doing so due to failing eyesight?

And for mr buffy: I was watching Bondi Rescue where two people were pulled unresponsive and unconscious from the water. One died, but the other was resuscitated. The resus patient was attended by paramedics who put her “into an induced coma” for transportation to the hospital. I wasn’t aware that paramedics could do this and am wondering under what circumstances they would consider implementing the procedure?

Unless your Mum has been seeing the same practitioner for quite a few years, I’m not sure on what they are basing the two years estimate. Most people I see progress pretty slowly and you can adjust their glasses to compensate for quite a long time. A very few progress from OK to “goodness, I’d better refer you” in about 6 months. The progression of cataracts is very, very variable. I never, ever make predictions. Someone can be puddling along slowly getting hazier and then change more quickly, and then slow down again. I have to factor in waiting periods for surgery too.

The genetics is a bit of a hard thing to fathom. As cataract is essentially an ageing of the lens of the eye, probably because of light and UV degradation over time (think how plastics change in the sun), if you live long enough pretty much everyone gets cataracts. There are not more people with cataracts now than 50 odd years ago….there are more older folks. And the surgery is done very much earlier than it was done even 35 years ago when I started in practice. So there is a genetic component, but probably a lot more is environmental.

Most people I send off for surgery are in their mid 70s. But I am not dealing with a picky city population. I deal with pensioners who mind their pennies and don’t want to do anything until it is necessary (farmers). There are some in their late 60s. And I have a few well into their 80s and 90s who still haven’t needed to go.

My routine with a person in their 60s whose vision is just starting to be compromised is to see them again after 6 months to see if they are a fasty or a slowy. The fasties I see 6 monthly to gauge speed of change and I refer when it looks like the next 6 month check will involve saying “you don’t quite reach the driving vision level now”. The slowies I put on 12 month recalls. All of them know to come back sooner if they notice change sooner.

Cataract surgery is the removal of the natural lens inside the eye, and replacement with a plastic artificial lens. So cataract can’t come back. There are multifocal intra-ocular lenses these days. A couple of the surgeons I refer to use them, a couple of others say they are not good enough yet. I have seen patients post surgically who were very happy. And some who hated it. Usually they aim to correct distance vision and you still use reading glasses for close stuff. The multifocal intra-ocular lenses require you to rewire your brain for seeing. Older folk can have a lot of trouble with this. Even if such a lens is used, there is no guarantee that you won’t need some glasses, perhaps for night driving, perhaps for fine close work.

Very few people have to relinquish their licence because of cataract. Mostly it would be due to macular degeneration. I’ll push a cataract person to have surgery rather than give up their licence….the licence is very difficult to get back again when you are old.

Is that all? I think I’ve answered all the bits.

> Does cataract surgery have long-lasting effects or is it only effective for a relatively short time? For people who do have to relinquish driving, what’s the average age for doing so due to failing eyesight?

What Buffy said.

My mother and father in law both had cataract surgery and for both the improvement lasted the rest of this lives.

My mother, grandmother and stepfather all eventually had to relinquish driving. My mother volunterily, but following a car accident, in her mid eighties. My grandmother involuntarily after failing a driving test in her mid eighties. Neither of those because of eyesight. My stepfather first went onto a restricted driving license that limited distance and stopped him driving at night at about age 90 because his night sight and peripheral vision wasn’t good enough, then about age 96 stopped completely.

mollwollfumble said:

> Does cataract surgery have long-lasting effects or is it only effective for a relatively short time? For people who do have to relinquish driving, what’s the average age for doing so due to failing eyesight?

What Buffy said.

My mother and father in law both had cataract surgery and for both the improvement lasted the rest of this lives.

My mother, grandmother and stepfather all eventually had to relinquish driving. My mother volunterily, but following a car accident, in her mid eighties. My grandmother involuntarily after failing a driving test in her mid eighties. Neither of those because of eyesight. My stepfather first went onto a restricted driving license that limited distance and stopped him driving at night at about age 90 because his night sight and peripheral vision wasn’t good enough, then about age 96 stopped completely.

I had the cataract in my right eye taken out in 2007, amazing improvement

> stepfather

Oops, I mean father in law.

> The resus patient was attended by paramedics who put her “into an induced coma” for transportation to the hospital. I wasn’t aware that paramedics could do this and am wondering under what circumstances they would consider implementing the procedure?

From vague memory this was described on “operation ouch”.

Wikipedia says that it helps in cases of severe head trauma, severe brain hemorrhage, and severe epileptic fits.

Without more info, I would speculate that ‘Induced Coma’ is TV-speak for anaesthesia with Ketamine, which is a very effective pain drug and dissociative that’s safe to use in the field for most patients because it doesn’t depress blood pressure, respiratory drive, or cause loss of control of airway.

<<Usually they="" aim="" to="" correct="" distance="" vision="" and="" you="" still="" use="" reading="" glasses="" for="" close="" stuff.="">> Could you choose the opposite – glasses for distance and intra-ocular lenses set for close up?

I’ve heard that in some cases, one eye is set for close up, the other for distance. The brain become adept at selectively processing the input from whichever eye is appropriate. How satisfactory is this? Does this destroy depth perception?

pesce.del.giorno said:

<<Usually they="" aim="" to="" correct="" distance="" vision="" and="" you="" still="" use="" reading="" glasses="" for="" close="" stuff.="">> Could you choose the opposite – glasses for distance and intra-ocular lenses set for close up?

I’ve heard that in some cases, one eye is set for close up, the other for distance. The brain become adept at selectively processing the input from whichever eye is appropriate. How satisfactory is this? Does this destroy depth perception?

Different eyes for some optometry patients focus at different distances but we correct for that using lenses or surgery.

I focus at different distances with my eyes. When reading a book without glasses, my right eye tends to take over, which can be annoying, I keep having to remind myself to open my left eye.

My personal opinion is that the value of binocular vision for depth perception is overrated. There are at least ten different ways by which human beings perceive depth. Binocular vision is most useful when walking on a surface that is near-constant colour and near-uniformly lit. It’s much less used in the perception of the distance to doorways and plays a negligible role in depth perception when driving and sight seeing. There are many good drivers who only have good vision in one eye.

Having eyes set for different distances allows me to use that difference for depth perception. Though for me it’s only useful very close up.

>>I’ve heard that in some cases, one eye is set for close up, the other for distance. The brain become adept at selectively processing the input from whichever eye is appropriate. How satisfactory is this? Does this destroy depth perception?<<

In a word..yes. To a degree. The search term you need is stereopsis. What you are describing is known as monovision. We sometimes do it with contact lenses and most but not all people adapt reasonably well to it for general daily eye use. But monovision means your fine stereopsis – by virtue of the fact that your eyes are set horizontally apart in your head – no longer works effectively. You use your stereopsis for threading needles, judging where stuff is on the table in front of you, picking up your wine glass or cup of tea/coffee. Killing stereopsis can make you clumsy and you may not adapt. And it’s harder to adapt if you are older. And many cataract surgery people are older.

Here are a couple of little experiments to show you about stereopsis.

If you have an outside clothes line, stand under it, look up at one string with a clear sky background, and put out a hand to touch the string. Because the image of the string is the same in each eye because it is horizontal, you will quite possibly miss. Your brain needs two pieces of information to place something in 3D space accurately at close distances. Now, try that again, but with one hand touching the string. You will be spot on accurate, because you sent a visual image of a horizontal line, plus the proprioceptive information via your spine to your brain.

Now, simulate losing an eye and hence stereopsis. Get a jug and a glass and put them on the draining board of the sink. I don’t recommend doing this on a table. Fill the jug with water. Now, without touching the glass with your other hand, close one eye, and pour the water into the glass. It is likely you will miss and make a mess. I teach my patients who have lost sight in one eye to always touch the glass/cup while they are pouring.

>>My personal opinion is that the value of binocular vision for depth perception is overrated. There are at least ten different ways by which human beings perceive depth. Binocular vision is most useful when walking on a surface that is near-constant colour and near-uniformly lit. It’s much less used in the perception of the distance to doorways and plays a negligible role in depth perception when driving and sight seeing. There are many good drivers who only have good vision in one eye.<<

Stereopsis is really useful for close distances only, generally considered to be out to around 10m (I think, can’t remember the exact distance), and mostly within arms’ length anyway for manipulating things with your hands. However, some people have done some experiments showing it does work at greater distances. At the greater distances our brains use those other things like parallax, overlapping etc.

So this effectively renders our distance vision monocular – with the associated visual field issues. Do you know what the implications of this for an aviation medical would be?

pesce.del.giorno said:

So this effectively renders our distance vision monocular – with the associated visual field issues. Do you know what the implications of this for an aviation medical would be?

No, it is binocular. You use parallax and head movement cues amongst other things, which require two eyes.

buffy said:

pesce.del.giorno said:

So this effectively renders our distance vision monocular – with the associated visual field issues. Do you know what the implications of this for an aviation medical would be?

No, it is binocular. You use parallax and head movement cues amongst other things, which require two eyes.

I wonder how that works, then. As I’ve mentioned before, I’ve got a keratoconus in my right eye, which leaves me, in the words of one ophthalmologist, “no useful vision in that eye” without a contact lens, but useful 3D vision, even without the contact lens.

Here you go. It’s a pdf of a textbook chapter about depth perception in humans. There is a bit of reading.
It tells you about most of the ways we work it out.

https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&ved=0ahUKEwipstzqkM7TAhXEv7wKHTgVBHE4ChAWCCAwAA&url=https%3A%2F%2Fwww.ics.uci.edu%2F~majumder%2Fvispercep%2Fchap8notes.pdf&usg=AFQjCNEDdd0H_3eCgbbktz3cqyF0yYG8_w&cad=rja

buffy said:

Here you go. It’s a pdf of a textbook chapter about depth perception in humans. There is a bit of reading.
It tells you about most of the ways we work it out.

https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&ved=0ahUKEwipstzqkM7TAhXEv7wKHTgVBHE4ChAWCCAwAA&url=https%3A%2F%2Fwww.ics.uci.edu%2F~majumder%2Fvispercep%2Fchap8notes.pdf&usg=AFQjCNEDdd0H_3eCgbbktz3cqyF0yYG8_w&cad=rja

Thanks buffy. Here’s a shorter link to that text, linkified even: https://www.ics.uci.edu/~majumder/vispercep/chap8notes.pdf

Ta.