Cause of Vision Loss & Treating Vision Loss | Dr. Jeff Goldberg & Dr. Andrew Huberman
00:00:00.000 | - What are the major forms of vision loss
00:00:05.140 | in childhood and in adulthood?
00:00:07.360 | And what can each and all of us do
00:00:09.700 | in order to find out if we have one of these conditions
00:00:12.860 | and therefore treat it effectively?
00:00:15.140 | - Yeah, that's great.
00:00:16.540 | You know, let's start by just reminding ourselves
00:00:20.920 | what are the major causes of vision loss?
00:00:23.740 | And these are gonna differ where you are in the world,
00:00:27.280 | but the number one cause of low vision
00:00:30.100 | is actually refractive error.
00:00:32.580 | People who need glasses and especially in other countries,
00:00:37.480 | affordability, access, can't even get glasses, okay?
00:00:42.080 | So that's just refractive error,
00:00:43.960 | but that's fundamentally correctable.
00:00:47.140 | The next most common cause of vision loss is cataract.
00:00:51.640 | Cataract is the blurring, the aging of the lens
00:00:55.840 | inside the eye, behind the cornea.
00:00:57.720 | We talked about how that is responsible
00:01:00.080 | for focusing light under the back of the eye.
00:01:02.000 | It also has to be clear enough
00:01:03.240 | that the light gets through the lens.
00:01:05.640 | And a cataract is a normal aging process.
00:01:08.960 | You know, as I said, if we all live to 100
00:01:10.800 | or 110 years old, we'll all get cataracts,
00:01:13.200 | we'll all need cataract surgery.
00:01:14.960 | We actually, as you know, in the eye clinic,
00:01:17.400 | we see cataracts years or even decades
00:01:21.080 | before they're affecting your vision in a meaningful way.
00:01:24.480 | So the cataracts are forming and that's okay,
00:01:26.960 | but at some point they get bad enough
00:01:29.620 | that it's time to take them out.
00:01:31.560 | We've actually solved for cataract surgery
00:01:34.500 | pretty efficiently.
00:01:36.320 | We can do a four to eight minute surgery.
00:01:39.500 | Maybe if we're taking our time,
00:01:40.820 | it's 10 or 12 minutes of surgical time.
00:01:44.040 | Take out a cataract.
00:01:45.460 | It works beautifully 99 point something percent of the time.
00:01:50.220 | We put a plastic, a clear plastic lens inside the eye,
00:01:53.800 | exactly where your lens used to be.
00:01:56.400 | And there's even lenses that can flex
00:01:59.480 | or focus light from far and near.
00:02:01.720 | So cataract is fundamentally a,
00:02:04.160 | there's still room for improvement,
00:02:05.320 | but it's fundamentally a solved problem.
00:02:08.960 | The problem is, is that worldwide,
00:02:11.560 | there aren't enough cataract surgeons.
00:02:13.780 | There's not access to care.
00:02:15.860 | The machinery or the lenses cost too much money
00:02:20.600 | in developing countries to get out to the number of people
00:02:24.720 | who would need them.
00:02:26.060 | So it's actually just, again, an access to care.
00:02:28.320 | Cataract is a reversible, treatable,
00:02:31.200 | easily treatable problem,
00:02:32.960 | but it's number two on the list of causes of vision loss
00:02:37.520 | in the world because we don't have enough access to care.
00:02:39.900 | We need a lot more sort of programming
00:02:42.280 | around global ophthalmology, global eye care
00:02:44.500 | to solve for cataract,
00:02:46.460 | just to bring that solution to countries around the world.
00:02:50.920 | Then after that, you start hitting the eye diseases
00:02:55.200 | that lead to what are currently irreversible,
00:02:59.160 | non-reversible causes of vision loss.
00:03:02.920 | The number one cause of irreversible vision loss
00:03:06.840 | in the world is glaucoma.
00:03:09.600 | So what is glaucoma?
00:03:10.440 | Glaucoma is actually probably a little cluster
00:03:12.680 | or constellation of diseases that we lump together.
00:03:16.120 | It's a degenerative disease, like a neurodegeneration.
00:03:20.840 | We talk about neurodegenerations in the brain,
00:03:22.760 | like Alzheimer's and Parkinson's.
00:03:24.480 | Glaucoma is a neurodegenerative disease.
00:03:27.560 | It happens instead of affecting one or a different area
00:03:30.360 | in your brain, it happens to affect the optic nerve
00:03:33.960 | that connects the eye to the brain.
00:03:35.480 | And we need our optic nerves to carry
00:03:37.080 | all the visual information from the eye to the brain.
00:03:40.400 | And so if your optic nerve is degenerating in glaucoma,
00:03:44.840 | and I should add, there are other optic neuropathies,
00:03:48.120 | so-called diseases of optic nerve degeneration.
00:03:50.600 | For example, you can get a stroke of the optic nerve.
00:03:53.520 | You can have an inflammatory disease
00:03:55.800 | like multiple sclerosis called optic neuritis
00:03:58.920 | that affects the optic nerve.
00:04:01.080 | So you can get other optic nerve diseases,
00:04:04.040 | but glaucoma is by far the most common optic neuropathy.
00:04:07.040 | And the problem is just like spinal cord injury,
00:04:11.480 | which is also part of the central nervous system,
00:04:14.080 | the brain, the spinal cord, the retina, the optic nerve,
00:04:16.400 | that's the central nervous system,
00:04:17.880 | and there's no regeneration.
00:04:19.960 | And that's why spinal cord injury
00:04:21.400 | leads to permanent paralysis,
00:04:23.600 | while optic nerve injury or optic nerve degeneration,
00:04:27.040 | unfortunately leads to permanent vision loss.
00:04:30.000 | So in the case of glaucoma, how do we get ahead of that?
00:04:33.640 | Glaucoma has two major risk factors.
00:04:36.840 | One is increasing age.
00:04:38.600 | There are actually infantile
00:04:40.880 | and pediatric glaucomas, unfortunately.
00:04:43.960 | And those can be much more aggressive,
00:04:45.800 | much more damaging when they present so early in kids,
00:04:49.920 | in babies and in children.
00:04:51.560 | Most of the kind of run-of-the-mill glaucoma
00:04:54.720 | usually presents in adulthood and even in the aging adults.
00:04:58.720 | So much more common after 50 or 60 or 70 years old,
00:05:01.960 | increasing.
00:05:03.280 | The other main risk factor for glaucoma
00:05:05.360 | is increasing eye pressure.
00:05:07.560 | The eye actually, you know, it stays inflated.
00:05:10.280 | It's a balloon, it has to stay inflated.
00:05:12.240 | We need some amount of eye pressure to keep our eye
00:05:14.800 | as an inflated balloon.
00:05:16.760 | But if the eye pressure goes too high,
00:05:19.880 | and we talked about this before,
00:05:21.280 | you won't even feel it if it slowly gets too high.
00:05:24.680 | If the eye pressure goes too high, that causes glaucoma.
00:05:29.320 | And that's one of the things that we talked about,
00:05:32.440 | you really include in a comprehensive eye exam
00:05:36.080 | when you're just getting a screening checkup
00:05:38.400 | at your eye care provider,
00:05:39.800 | at your optometrist or ophthalmologist office.
00:05:42.040 | They're gonna check your pressure.
00:05:43.360 | And just as a screening tool,
00:05:44.760 | check to make sure it's not too high.
00:05:46.600 | We can treat glaucoma today
00:05:51.840 | by trying to reduce the impact of that high pressure
00:05:55.000 | by lowering the eye pressure.
00:05:57.120 | So we have treatments for glaucoma
00:05:59.200 | that target the eye pressure.
00:06:00.600 | We have medications like eye drops.
00:06:03.120 | We have lasers that can be used inside the eye
00:06:06.080 | that can also lower the eye pressure.
00:06:08.880 | And ultimately, if we need them,
00:06:10.000 | we also have surgeries that can also provide an outflow
00:06:14.040 | that lets the fluid out of the eye in a controlled way
00:06:17.360 | so that the eye pressure can be brought back down
00:06:19.600 | into normal ranges.
00:06:21.160 | Again, the reason that glaucoma
00:06:24.640 | ends up being the number one cause
00:06:28.160 | of irreversible blindness in the world
00:06:30.680 | is number one, we can't get those therapies
00:06:34.720 | everywhere in the world.
00:06:35.800 | The affordability of eye drops,
00:06:37.800 | the access to lasers or surgical procedures around the world
00:06:41.320 | isn't equal to what it is here.
00:06:43.920 | And even within our country,
00:06:46.320 | people may not be accessing healthcare effectively
00:06:49.400 | to get screened for glaucoma
00:06:50.880 | or to get treated for glaucoma.
00:06:52.920 | The other big problem with glaucoma
00:06:54.760 | is that it affects our peripheral vision first.
00:06:58.680 | And only very late in the disease does it pinch in
00:07:02.880 | and finally pinch off the center of our vision
00:07:05.400 | in typical glaucomas.
00:07:08.120 | And that's a real problem because we don't notice
00:07:12.040 | if our peripheral vision is down.
00:07:14.160 | You know, our peripheral vision isn't that good
00:07:16.600 | to begin with.
00:07:17.560 | And if you're driving and you can see a pedestrian
00:07:20.240 | step off the sidewalk,
00:07:21.520 | you think your peripheral vision is fine,
00:07:24.280 | but actually your peripheral vision could already
00:07:26.960 | start being damaged by glaucoma
00:07:28.800 | and you won't notice it in regular daily life.
00:07:31.920 | And that's where the importance of screening
00:07:34.720 | and early detection really comes in for glaucoma.
00:07:37.720 | What we don't have for glaucoma,
00:07:40.760 | we can come back to like kind of what's the cutting edge
00:07:43.160 | or the future in these eye diseases.
00:07:45.440 | What we don't have are treatments that really target
00:07:48.640 | the optic nerve degenerative process.
00:07:51.600 | And we can come back and talk about that.
00:07:54.480 | So that's glaucoma and optic neuropathies.
00:07:57.000 | Then the next two major causes
00:08:00.960 | of currently largely irreversible vision loss
00:08:05.320 | are age-related macular degeneration
00:08:08.200 | and then diabetic retinopathy.
00:08:12.840 | Now age-related macular degeneration is just like it sounds.
00:08:17.240 | Major risk factor is age.
00:08:19.160 | It's very common and actually in the developed world,
00:08:23.040 | you know, countries that are more developed,
00:08:24.480 | also countries that have a larger Caucasian,
00:08:27.120 | white population, it's more common in certain populations
00:08:30.440 | than in others.
00:08:32.200 | It actually is, you know, definitely a leading cause
00:08:35.920 | of vision loss in the elderly population,
00:08:38.520 | for example, in the United States.
00:08:40.440 | And there's two forms of macular degeneration,
00:08:46.720 | but they both end up targeting the same part,
00:08:50.440 | the same part of the retina.
00:08:52.120 | And the part of the retina is really like the rods
00:08:54.640 | and the cones that we talked about before.
00:08:56.440 | The rods do your low light vision at nighttime,
00:09:00.120 | primarily your cones do color vision and bright light,
00:09:03.560 | you know, sort of normal lighting that we experience,
00:09:06.160 | you know, through most of our awake day.
00:09:08.200 | And in that back of the retina,
00:09:11.360 | you can have what's called dry macular degeneration,
00:09:15.160 | which is a slow, thankfully slow,
00:09:18.200 | but slow insidious disease that causes the degeneration
00:09:23.200 | of the rods and cones and also the support cells
00:09:26.840 | that help feed the rods and cones
00:09:28.480 | and take care of the rods and cones.
00:09:30.080 | They're called RPE cells, retinal pigment epithelium.
00:09:33.440 | It's not really critical, of course,
00:09:35.800 | the names of every different cell type,
00:09:37.560 | but these are like the light collecting cells
00:09:41.240 | in our eyes in the retina,
00:09:42.400 | and they degenerate in macular degeneration.
00:09:45.280 | And in the dry form, there's the slow degeneration,
00:09:48.600 | but some percent of people with the dry form
00:09:51.240 | of macular degeneration will actually convert
00:09:53.360 | to what's called the wet form.
00:09:55.680 | It's called wet because new blood vessels
00:09:58.240 | actually grow inappropriately under
00:10:01.440 | and even into the retina, and new blood vessels,
00:10:04.720 | unlike our mature blood vessels, tend to be leaky.
00:10:08.160 | And so the fluid leaks out of those blood vessels,
00:10:11.320 | gets into the retina, interferes with vision,
00:10:13.480 | and that can lead to a much more acute loss of vision.
00:10:17.560 | Now, we have some treatments for wet macular degeneration.
00:10:22.560 | We have injections that can go into the eye
00:10:25.040 | that actually fight against the molecules
00:10:28.160 | that are causing those new blood vessels to grow.
00:10:31.240 | And these are antibodies that can be injected into the eye,
00:10:33.720 | and they can be very effective
00:10:35.680 | controlling patients' wet macular degeneration.
00:10:39.000 | It's been a much bigger uphill battle,
00:10:42.440 | even over the last decade as advances are being made
00:10:46.080 | to really try to knock back or slow down
00:10:49.480 | even the dry form of macular degeneration.
00:10:53.640 | There was just some exciting news,
00:10:55.320 | even just in the last few months.
00:10:57.160 | The first successful trials of a treatment for the dry form
00:11:02.160 | have just shown success in properly randomized,
00:11:07.000 | controlled human clinical trials,
00:11:09.040 | phase three clinical trials.
00:11:11.120 | So it's an exciting time.
00:11:14.000 | Those new treatments are not gonna be a panacea.
00:11:16.840 | They slow the progression,
00:11:18.960 | like the anatomic progression of the disease,
00:11:22.520 | maybe by 20 or 25%.
00:11:25.720 | And so patients are still gonna get worse
00:11:27.840 | even with those treatments.
00:11:29.200 | So there's still a lot more to be done
00:11:31.560 | to really knock back macular degeneration.
00:11:34.960 | I wanna mention, you mentioned retinitis pigmentosa.
00:11:37.840 | That's like an inherited form
00:11:40.440 | of a type of macular degeneration.
00:11:42.920 | It's also affecting the rods and cones
00:11:45.680 | and also the support cells,
00:11:47.040 | the RPE cells in the back of the eye.
00:11:49.160 | Retinitis pigmentosa is an inherited form.
00:11:53.200 | There are actually many different genes you could have
00:11:56.560 | that could lead to retinitis pigmentosa.
00:11:59.200 | In aggregate, if you add up all the people
00:12:02.400 | with all those different genes,
00:12:05.040 | and it can be very devastating
00:12:07.440 | 'cause it can really affect the vision,
00:12:09.000 | knock out your vision very early in life,
00:12:10.960 | including in children
00:12:12.000 | and even for versions of that in babies.
00:12:14.840 | But you add that all up,
00:12:15.920 | it's still much less common in aggregate
00:12:18.280 | than macular degeneration.
00:12:20.520 | But in a way, it's quite a bit more severe
00:12:23.040 | because it does affect people much earlier in life.
00:12:25.640 | So I sort of clump those together,
00:12:28.040 | macular degeneration, retinitis pigmentosa,
00:12:30.160 | degeneration of the rods and cones
00:12:33.080 | and the support cells, the RPE support cells.
00:12:36.160 | And then you can't have this part of the discussion
00:12:39.280 | about what are the devastating eye diseases
00:12:41.360 | without bringing up diabetic retinopathy,
00:12:43.360 | especially because diabetes,
00:12:47.000 | unfortunately, really continues to grow in,
00:12:50.480 | especially, let's say in the United States,
00:12:53.000 | certainly in the developed world.
00:12:54.880 | As we, especially type two diabetes with eating habits,
00:13:00.480 | exercise habits, contributing to a proliferation
00:13:04.160 | of some of the risk factors for type two diabetes,
00:13:06.840 | metabolic syndrome, obesity,
00:13:09.400 | we're unfortunately seeing a proliferation,
00:13:13.120 | a growth in the number of people with diabetes.
00:13:15.800 | And with the growth in diabetes,
00:13:17.720 | unfortunately comes a growth of the complications
00:13:20.960 | of diabetes.
00:13:21.800 | And one of the major complications of diabetes
00:13:25.480 | is damage to the retina inside the eye.
00:13:27.880 | And we call that diabetic retinopathy.
00:13:30.680 | And there again, some of the same damage that occurs,
00:13:35.400 | especially when in diabetes, again,
00:13:37.480 | some new blood vessels are growing
00:13:39.400 | or blood vessels are leaky.
00:13:41.160 | Some of that can be treated with,
00:13:43.920 | used to be lasers and now more commonly
00:13:46.400 | is often being treated with some of the same
00:13:48.920 | injectable drugs that are treating macular degeneration.
00:13:52.400 | But there's still a lot of vision loss with diabetes
00:13:56.680 | and diabetic retinopathy.
00:13:58.760 | I think that's an area where again,
00:14:01.440 | early screening, making sure if you have diabetes,
00:14:05.000 | that's an indication where you definitely
00:14:07.280 | have to be going in and getting your,
00:14:09.160 | at least annual exam with an eye care provider
00:14:12.840 | or having someone take a photograph
00:14:14.520 | of the inside of your eye and rate that photograph
00:14:17.360 | to say if you have any diabetic retinopathy or not.
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