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On Wednesday i went to the optometrist. How long is an appointment? Fairly long, it turns out, when you are living at a center of the high tech universe and the principal of the practice appears to have a fetish for new scanning equipment.
Some years back, an "optic nerve head drusen" was observed in my left eye. I recorded my first reaction about having to go get a sonogram in my eye: how urgent was this really? Gurdonark's rule that you don't mess around with taxes, foreclosure notices or optical nerve disorders still seems sound, but i can't help but feel that the continued monitoring of the stable, probably congenital condition is required to help subsidize the cost of the fancy scanning equipment.
Oh, but what fancy scanning equipment they have now! Instead of having to make another appointment and shuttle myself off hither and yon, my optometrist now has a laser eye imager that makes a three dimensional scan of the back of my eye. I was reminded of seeing the data from a lidar scan of Santa Clara county some years back: the whole stack of technology amazes me.
Lidar is a scanning technology where aircraft fly a pattern over an area running a laser scan of the ground surface. The Santa Clara scan had something like a 3 cm resolution on the valley floor, meaning the data scan can place a curb within 3 cm of its actual location, by virtue of running a laser over a 3 cm grid of the entire valley. With my eye, in just a few moments, hundreds of scans were taken, and the resolution was such that the optic nerve looked like that Tatooine monster in Return of the Jedi. (Christine's asleep, or i'd ask her for it's name.)
So just the mechanics of creating such a laser scan is mechanically impressive. Next there's the interpretation of laser reflectivity to build a model that goes more deep than the surface. With lidar scans of land, multiple reflections come back. How the lidar reflects from, is absorbed by, and penetrates vegetation, mud, sand, etc is well understood. Given a laser pulse, multiple reflections are returned at different times. The time gives the distance from the source, the amount of light returned indicates what the laser is hitting at that distance. A tree canopy might give a brief reflection of a certain intensity; sand will give a constant "smear" reflection as the lidar penetrates the material.
Presumably, they've worked out the the same absorption and reflection behaviors for all that goes on in an eye. After the zip, zip scan of my eye, the technician returned me to the exam room, and brought the data up on the computer for the doctor.
And here's more amazement: the office computers are now sufficient to take a huge amount of data and interpret it on the fly, networks are reliable, and when the doctor returned we were navigating X and Y slices and looking at the composite 3D model, zooming around (and through) capillaries and nerves.
I have a lovely right eye, symmetric sinkhole of an optic nerve, and a misshapen lumpy left optic nerve, with some mass of cloudy stuff interfering with the signal from my eye to my brain. That mass, the drusen, has probably been there since i had an optic nerve. Some transposed characters in the DNA instructions i imagine, and i imagine a harried DNA-reading line manager tossing off a chunk of DNA to the cell building engineers. "Look, this is what product spec'ed out. Just do it so we can get on to laying that nerve line back to the brain, OK?"
So, they will want to image it again in a few years, and they will charge my medical plan for the test. I'll be assured that my bad vision in my left eye is still from the same cause that had me wearing a patch over my right eye when i was 6. I suspect it won't be as marvelous: the jump from the 2007 sonogram to the 2011 lidar was incredible. The jump between my "optimap" scans was a refinement in resolution, but not as impressive as the improvement in the cameras between my Palm Treo and my EVO. I suspect the software will do the quick analysis on the base line scan and compare the then current cloudy mass to that imaged Wednesday, highlight any discrepancies in false color, and at a glance the optometrist will be able to confirm for me that my condition is stable.
But i'm still amazed when i go to the dentist and have the x-ray image appear on the screen immediately after hearing the digitized voice carefully enunciate, "Radiation detected." Maybe in a few years i'll be looking forward to the chance to see the 3D fly through again.
Some years back, an "optic nerve head drusen" was observed in my left eye. I recorded my first reaction about having to go get a sonogram in my eye: how urgent was this really? Gurdonark's rule that you don't mess around with taxes, foreclosure notices or optical nerve disorders still seems sound, but i can't help but feel that the continued monitoring of the stable, probably congenital condition is required to help subsidize the cost of the fancy scanning equipment.
Oh, but what fancy scanning equipment they have now! Instead of having to make another appointment and shuttle myself off hither and yon, my optometrist now has a laser eye imager that makes a three dimensional scan of the back of my eye. I was reminded of seeing the data from a lidar scan of Santa Clara county some years back: the whole stack of technology amazes me.
Lidar is a scanning technology where aircraft fly a pattern over an area running a laser scan of the ground surface. The Santa Clara scan had something like a 3 cm resolution on the valley floor, meaning the data scan can place a curb within 3 cm of its actual location, by virtue of running a laser over a 3 cm grid of the entire valley. With my eye, in just a few moments, hundreds of scans were taken, and the resolution was such that the optic nerve looked like that Tatooine monster in Return of the Jedi. (Christine's asleep, or i'd ask her for it's name.)
So just the mechanics of creating such a laser scan is mechanically impressive. Next there's the interpretation of laser reflectivity to build a model that goes more deep than the surface. With lidar scans of land, multiple reflections come back. How the lidar reflects from, is absorbed by, and penetrates vegetation, mud, sand, etc is well understood. Given a laser pulse, multiple reflections are returned at different times. The time gives the distance from the source, the amount of light returned indicates what the laser is hitting at that distance. A tree canopy might give a brief reflection of a certain intensity; sand will give a constant "smear" reflection as the lidar penetrates the material.
Presumably, they've worked out the the same absorption and reflection behaviors for all that goes on in an eye. After the zip, zip scan of my eye, the technician returned me to the exam room, and brought the data up on the computer for the doctor.
And here's more amazement: the office computers are now sufficient to take a huge amount of data and interpret it on the fly, networks are reliable, and when the doctor returned we were navigating X and Y slices and looking at the composite 3D model, zooming around (and through) capillaries and nerves.
I have a lovely right eye, symmetric sinkhole of an optic nerve, and a misshapen lumpy left optic nerve, with some mass of cloudy stuff interfering with the signal from my eye to my brain. That mass, the drusen, has probably been there since i had an optic nerve. Some transposed characters in the DNA instructions i imagine, and i imagine a harried DNA-reading line manager tossing off a chunk of DNA to the cell building engineers. "Look, this is what product spec'ed out. Just do it so we can get on to laying that nerve line back to the brain, OK?"
So, they will want to image it again in a few years, and they will charge my medical plan for the test. I'll be assured that my bad vision in my left eye is still from the same cause that had me wearing a patch over my right eye when i was 6. I suspect it won't be as marvelous: the jump from the 2007 sonogram to the 2011 lidar was incredible. The jump between my "optimap" scans was a refinement in resolution, but not as impressive as the improvement in the cameras between my Palm Treo and my EVO. I suspect the software will do the quick analysis on the base line scan and compare the then current cloudy mass to that imaged Wednesday, highlight any discrepancies in false color, and at a glance the optometrist will be able to confirm for me that my condition is stable.
But i'm still amazed when i go to the dentist and have the x-ray image appear on the screen immediately after hearing the digitized voice carefully enunciate, "Radiation detected." Maybe in a few years i'll be looking forward to the chance to see the 3D fly through again.
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