Sand, sun, and your eyes

A flats guide with a permanent squint and a scooter rider with streaming, grit-filled eyes, stopped at the same red light on North Roosevelt: two versions of the same island physics, which is that everything here reflects. Here is the whole protective plan up front. Wear sunglasses that block 100 percent of UV, the ones labeled UV400, wraparound style if you are on the water, add a brim, and never, ever rub a sandy eye. Everything else in this column is the why. Your eyes sunburn like skin, glare off the water doubles the dose, and a rubbed grain of sand writes a scratch across the cornea that will feel like the grain never left.

Glare and photokeratitis

The cornea can sunburn exactly the way your shoulders do, and the condition has a name: photokeratitis. Hours of reflected UV off water and white sand deliver the dose, and, like a sunburn, the pain arrives on a delay. You feel great on the sandbar and wretched that evening: gritty, watering eyes, a stabbing sensitivity to light, the sense that something is lodged under the lids when nothing is. Per the American Academy of Ophthalmology, it typically heals on its own in a day or two, which is reassuring and does nothing for the misery of the night you spend with the lights off. The fix is prevention, worn on your face, because there is no lotion for the eye.

The long game

Two slower problems reward a lifetime of good sunglasses. Pterygium, the fleshy growth nicknamed surfer's eye, creeps across the surface of the eye and tracks tightly with years of UV, wind, and dust exposure; it is over-represented in exactly the people who work on the water here, the guides and the dock crews. And cumulative UV raises cataract risk over decades, quietly, the way sun does most of its damage. Neither is an emergency, and both are partly preventable with the same cheap habit: real UV protection, worn young and worn often, on the theory that your future eyes will send thanks.

Polarized versus protected

This is the distinction the sunglasses rack will not explain honestly. Polarization kills glare, which is why the flats guide can see the fish and the tarpon under the surface; it is a comfort and performance feature, and a wonderful one on the water. But polarization by itself does nothing for UV. The medical protection is the UV filter, and you confirm it by the label: UV400, or 100 percent UV. A ten dollar pair that says UV400 protects your eyes better than a two hundred dollar pair that only says polarized. On the water you want both, but only one of them is medicine, and it is the boring one. The same UV that burns your eyes is burning the rest of you too, which the sunburn column handles, and the live number is on this week on the island.

Sand in the eye, done right

Do not rub. Everything else is negotiable; that one is not. Sand plus a rubbing knuckle equals a corneal abrasion, trading a passing irritation for a genuine injury. Instead, flush with clean water or saline, and plenty of it. Blink deliberately to let your tears work. Pull the upper lid out and down over the lower lid, a trick that sweeps the underside clean. If it clears, you are done. Here is the part that fools people: after a real abrasion, the eye still feels like the sand is in there long after it is gone, because the scratch itself is the sensation. Most abrasions heal in 24 to 48 hours, but worsening pain, light sensitivity that climbs, or any change in vision gets seen the same day, not slept on.

Questions from the beach

Sources

• American Academy of Ophthalmology, photokeratitis (UV corneal burn, delayed onset, heals in a day or two).
• American Academy of Ophthalmology, pterygium and cumulative UV (association with UV, wind, and outdoor work; cataract risk over decades).
• American Academy of Ophthalmology, sunglasses and UV protection (UV400 versus polarization; the label is the protection).