Potential major adverse effects of flicker identified in published research and/or Expert Opinion include these five factors
- Photoepilepsy or flashing-light induced seizure.
- Stroboscopic effect and associated apparent slowing or stoppage of rotating machinery.
- Migraine or severe paroxysmal headache often associated with nausea and visual disturbances.
- Increased repetitive behavior among persons with autism.
- Asthenopia, including eyestrain, fatigue, blurred vision, conventional headache, and decreased performance on sight-related tasks.
Pros: The bulbs are indeed extremely bright, deliver all that light at excellent wattage, have no warmup time or initial flicker, and fit standard sockets. They've worked so well for lighting up the driveway that I intend to buy more for other areas where standard high wattage equivalent bulbs simply aren't bright enough, such as the basement or other wide open exterior areas. Probably not much for indoor use though, as just one will make an average sized bedroom too bright, if anything. That's how bright they are.
Cons: -The bulbs screw into standard sockets just fine, but they are overall wider than any other lightbulbs I've ever used, barely fitting into the outdoor light fixtures I installed them in. If regular bulbs are already a tight fit width-wise, these may not fit that location at all. They're also noticeably heavier than standard bulbs, so an extremely delicate or flimsy socket might not be up to the task for these particular bulbs. -The LEDs are all bunched toward the top of the bulb, resulting in less than perfectly balanced lighting. They certainly cast significant light in every direction, it's projected most strongly straight out and upward, and least of all downward. As such, the bulbs don't quite reach their full practical illumination potential when mounted in a standard upward orientation in high locations, especially without a good reflective surface above them.
Overall Review: If you have a standard lightbulb location somewhere but need a non-standard degree of brightness, I can't think of a bulb I'd recommend more. I'm not aware of any other alternative that delivers as much light, while taking up just barely more space than a standard bulb no less. And at a better price than far bulkier alternatives to boot. The only thing I'd like changed would be not bunching the LEDs up so much toward the top of the bulb exclusively. I suppose this design is just fine for high places if you want a bright ceiling, or the bulbs are installed in an upside down socket, but I feel like keeping the LEDs more to the middle would have yielded more balanced, and overall more useful results. Alternately, focusing the LEDs entirely toward the bottom half of the main bulb section could work too as an alternate companion design, then one could choose this version or the bottom-heavy version depending on intended height and orientation, to make sure light's best projected in the direction most needed. As is, unlike most any other bulbs where direction doesn't matter much, these bulbs may or may not shine their absolute brightest, depending on which direction you need their light the most and which orientation they'll be installed in. But even the least lit direction will still be brighter than any other bulb would have delivered.