That makes sense. Does this irritation occur while the brain is also compensating/covering up the damaged spot in your vision, or is that separate? I would think damage severe enough to cause strain while the brain is processing it, would still be at least a bit noticeable after the fact, no?
It dramatically depends on the magnitude of the burn, size of the burn spot, relation to location of optic nerve, and where the location is in the visual field.
Peripheral burns for example, might be almost un-noticable, until the truck hits you. Burns carefully placed to attach a detached retina might result in a general fuzzyness in the vision..
So there is no "typical" laser burn.
In my case, the tiny, tiny, burn received when a co-worker deviated from lock-out tag-out, was noticable for about five years off and on, with some headaches in direct sunlight. Now I cannot find the spot. I did watch the brain remap in real time, so I was lucky as mine was tiny, and barely in the main visual field. It was a moving, fuzzy, black spot on the edge of my main vision at 1 O'clock. However, all I had to do was rapidly pan my head from right to left, then I'd catch it.
It takes the brain quite a while to compensate. The headache lasted for days in my case.
You need to be watching a large white wall to see the remap, which is SCARY to watch. Evidently the brain is constantly using trial and error feedback via saccadic motion to align the eyes. I actually smile when people use the term Safety N**I to refer to me. I was asked to join LPF to encourage safety by some members of the laser show community. Hard to argue with the guy who has experienced the damage, right?
Less then 20-30 mW of 488 nm light in my case. Stupid College Senior Coworker flopped the lockuput tag off the safety key and turned on the show control computer, while I was forward of a laser show beam table. He could clearly see I was forward of the safety line. The 25 watt capable SP 171 was idling and cavity detuned to align the table at low power. All the shutter arms popped up as the computer reset the table during boot. Thus I got a painful 100-200 milliSecond exposure. (There is not always pain as a symptom!) That was 1989 or so.
I'll not regret saying a few weeks of pain, and horrible fear turned me into a laser safety martinet. With GOOD reason. I have a LSO cert for a reason.
My burn is no where near as bad as a friend with over 30 years in the business who looked down the bore wondering why his gas laser had no plasma. The start pulse fired late... He's missing about 1/4th the vision in one eye with NO recovery. That turned him into one of the world's leading eye safety experts. With a degree in Engineering on top of the LSO career.
Recovery or healing is is rare, very rare. What you get if your lucky is brain compensation, and no more. I've watched another person with a severe burn "Dodge and Weave" thru obsticles that are not there, when walking inside in dim light. As I say, no way to estimate what will happen for a given situation.
I've moved to to lab lasers, and knowing what can happen helps where your training newbies around 50 Joule pulses. They tend to pay more attention long term when you tell them your story. The "melted spot" retinal photo collection helps, too.
The quicker you get treatment, the more the surgeon can reduce the bleeding, swelling, and inflamation on the retina. That was not known when I received the injury. Old school logic was live with it, its permanent. New logic, treatment within a hour to a few hours can reduce lesion size or in bad cases, save the eye.
Steroids, Pain Killers, and Nutrients, can contribute to reduced permanent damage.
Problem is, most ER docs may not know what to do, and most optometrists (they make eye glasses!) would have no idea. But the way the medical system works, you often have to see one of them FIRST, especially because of medical insurance procedures. They then book you an appointment well after its too late to reduce the impact... You may have just have severe eyestrain from a near miss, or you may have trauma. More then one person(many airline pilots!) has painfully scratched a cornea or sclera from the dirty hand coming up to protect the un-injured eye. Either way you need to see a pro, and its worth it to strongly pressure for an emergency session with an expert "Opthalmic Surgeon, or Retinal Specialist"
End lesson rant exercise... If you want a second opine, ask Hakzaw, he knows me fairly well...
Steve,
