[kenbolton]

I wore glasses for a few years in high school because I had trouble seeing the blackboard from anywhere but the front row. I started hiking and kayaking every day, especially in places where I could see for many miles. I also migrated from CRT to LCD to LED screens, and more recently to e-ink devices when possible. Very fine print in a dark space is hard to read, but I can read a moving US license plate from six blocks away. Yesterday I recognized a friend a mile and a half away by their paddle-stroke. I am able to differentiate a bald eagle from an osprey at two miles based on the shape of the wings, and see a fish in talons at about a mile. (Friday I observed an osprey dive, catch a fish, head towards the nest, then get chased for thirty minutes by a bald eagle. Nasty, opportunistic birds, bald eagles. I get why Benjamin Franklin held them in such contempt. I lost the pair when they went behind a mountain about three miles away.) In speaking with ophthalmologists, there is wide support for my hypothesis that the near-daily outdoor activity and frequent change of focal distance–from a nautical chart on my foredeck to the bow wave of a tanker eight miles out–has preserved and likely improved my vision. The data: 20/20 in primary school, 20/23 in high school, 20/20 during my higher education, and 20/13 and improving as I approach retirement. A fun trick is to describe an approaching vessel before others have seen it.

[mbrameld]

    I am able to differentiate a bald eagle from an osprey at two miles based on the shape of the wings

I wonder how you judge the distances? I'm a helicopter pilot and I don't even bother looking for traffic farther than 2 miles out unless it's an airliner. I have radar telling me how far away they are so I know the distances are accurate.

[kenbolton]

I know the estuarine river very well in my part of the world and the approximate distances between various landmarks and aids to navigation. Places I don't know as well, I use nearby features: cars, houses, aids to navigation, etc., to approximate. Exact accuracy isn't critical as normal cruising speed is around four knots. I know the distance from the George Washington Bridge to the Statue of Liberty is about 12 miles, and about ten miles from the GWB to the Battery. It is about six miles from World's End to Anthony's Nose and the Bear Mountain Bridge. It is about 1.5 miles from Little Stony Point to Pollepel Island and another 1.5 to Denning Point.

I also know about how large the various adult birds appear at various distances, recognizing that there is some variability. If it really mattered, I could carry a range finder.

Navigating in the open ocean, with no landmarks, is a little different. I have two compasses: one on my deck and one in my life jacket with my marine radio. I keep a charged phone with GPS and local marine charts in a dry box in a dry bag in a dry hatch in my boat, but have yet to rely on it. I look up the velocity and direction of the predicted currents and keep a chart of that on the deck along with my navigational chart. I plot my course on the chart and note the headings to my next waypoint. I keep a duplicate of the predicted currents and headings in a waterproof notebook on my body in case the chart gets separated from my boat. I note my departure time and calculate my velocity based on my normal cruising speed, adjust that for conditions – wind, current, company – and go for it.

I practice this on my local waters because I've been enveloped by fog off the coast of Maine. In September 2019 at low tide in the morning, three of us in a line with about twelve inches between stern and bow, we were unable to see the other paddlers in their cockpits, which means visibility was no more than seventeen feet. We navigated by instruments, ocean swell, and wind direction for two hours before the fog burned off.

[amelius]

This makes me wonder: is there a lens that you could use instead of glasses that will make your computer screen appear as if it is further away? Could it help people regain their far-sight?

[Jenda_]

Sure, get convex lens ("reading glasses") of about +1 to +1.5D and make the IPD as low as possible to induce a prism https://en.wikipedia.org/wiki/Prism_correction#Prentice's_ru... (in layman terms, this will make the "rays" coming from your two eyes "cross" and intersect at a certain distance)

You can also use prismatic lenses as the induced prism probably won't be sufficient (but better than nothing), but my local shop does not make them, so I have no experience with this.

I am shortsighted and I have special glasses for computer/close work (reading, soldering), which are 1.5D weaker and the IPD is 10mm larger (as these are concave lenses, it's the opposite IPD manipulation than with convex). The induced prism for my glasses is about 2Δ.

I don't understand why this is not more popular, both among shortsighted (to have weaker glasses to use indoors) and healthy (to have "reading glasses"). Including the prism. Beware, that some doctors say that by using such "perfect" correction for e.g. your computer screen, your eyes will "get lazy". I don't think this is true, but YMMV.

Protip: there are online services that will just make you glasses, no questions asked, usually for $20 to $40 for basic glasses. Here in .cz we have optiscont, globally, there is zennioptical; you can also search aliexpress. I don't have any apparatus to measure the quality of the resulting lenses, they however seem "good enough".

[Elora]

> I also migrated from CRT to LCD to LED screens, and more recently to e-ink devices when possible.

I too use eInk whenever possible but that's just for reading (a passion of mine). All current computer monitors are LED AFAIK, is there any research tho that it's better for sight, or are you simply stating that you migrated as the technology changed?

I'm thinking that OLEDs are the best looking but one of their weaknesses often mentioned is that they aren't as bright; if you have lots of light (ideally natural sunlight) they may prove to be counterproductive if you have to strain to see due to appearing dim.

[shadowtree]

You're getting far-sighted as you're getting older.

[kenbolton]

More seriously, though, I am not far-sighted. I do not need corrective lenses to read books, newsprint, magazines, or labels at the grocery store despite the possible genetic predisposition baed on the need for reading glasses by my parents and siblings. I often have to read very fine details on nautical charts, sometimes in a seaway, sometimes at night with the use of a headlamp.

Exhaustion definitely changes my eyesight. I'm coming off of two days of kayaking and camping with high school kids followed by an intensive four hour lesson teaching rescues. (Imagine ~3600 boat-poses per hour, then subtract a few hundred and replace them with pulling swamped boats out of the water and across my lap to empty them, climbing out of the water and into the boat to demonstrate a dozen types of self-rescue.) I tried to read last night but my eyes could not focus; I vaguely remember making my way toward bed but woke up twelve hours later downstairs on the floor.

[kenbolton]

I call it "wisdom". :-)

[abledon]

do you work a regular programming 9-5 job infront of a screen...?

there is the Dasung E-ink 23" monitor

[kenbolton]

I try to work seven days a week four hours a day for the last ten years. It is an attempt to avoid burnout, but I also find I solve more of the truly hard problems away from the keyboard.

My fantasy setup: waterproof 13"-15" e-ink linux device with 16GB of RAM and mobile connectivity and a Twiddler X Lendal collab on a 210cm Cadence. A rollup waterproof full-size bluetooth keyboard would be adequate. The keyboard and e-ink device would both need tether points and/or internal flotation.