What lasers can make you blind [Kompatibilitetsläge]

1 What lasers can make you What lasers can make you blindblindblindblindbybyLars HodeLars HodeLars HodeLars HodeSwedish Laser-Medical Society Background: Background:Since 40 years, there are special rules and ii f hfilrestrictions for the use of certain lasers . The reason is that some laser types,The reason is that some laser types, sometimes are able to cause eye injury, also at distancealso at distance. What can happen if you by mistake look into a strong laser beam?look into a strong laser beam?If you can cut in steel then you canIf you can cut in steel, then you can destroy an eye. How dangeroustlldiff tl ?are actually different lasers ? The classification of lasers is almost the sameThe classification of lasers is almost the same everywhere in the world, but the rules concerning use of lasers and rules for permission and registration of instruments is very different.

2 E g in Sweden class4lasers for hair removal in Sweden class 4 lasers for hair removal, for tattoo removal, for wrinkle treatment etc, are completely free sincefive years. In most countries opeey ees eeyeasos ou esyou need a doctor behind you and in other countries the doctor has to be the therapist. Many people think that looking into a laser beam can make them that correct?Yes there are such lasers ! I will describeYes, there are such lasers ! I will describe some of them and show laser was never produced. But it is possible to make it, if penough money is available. It was constructed theoretically under Richard M. Nixons administration in USA and about6 MWadministration in USA and about 20 units was thought to circulate in satellites around the earth. The intention was to burn Weight 20 tonoutputRussian nuclear missiles when they came up through the atmosphere.

3 This laser could make you blind10 meter20 tonOutput power 6mWmake you mm6 mWThis laser, a laser diode, often used in a therapeutic laser 10 mmWeight 2pinstrument. This laser can not harm you. It can possibly heal 2 graman injured eye!Before One week later Two months laterThis fibroma was removed with a 15 watt surgical CO2laser, 50 mm focal that laser make you blind ? might burn the cornea in or near the focal area, but not make someone blind !An Alexandrite laser for hairlaser for hair this laser make you blind ?NOThese lasers can make you blindBut they are very expensive very heavyBut they are very expensive, very heavy and takes a lot of kilowatts to runThis laser can make you blindyPrice: 380,000 A Q-switched Nd:YAG-laser can it make you bl d fhhNOblind if someone shoots right into your eyes?

4 NODart arrows ..Dart arrows ..Price: .. can make an eye can make an eye can make an eye can make an eye blindEttiEar protection must be worn too!A slingshot can make you blind . It can be used by anyone older than 5. It is very cheap. You don t need a responsible doctor ..No comments ! ! !Bullet proof vest must be would be much safer if it was a class 4 laser;if it was a class 4 laser; they might cause an injury but they can tinjury, but they can t make you laser risksOther laser risksOther laser risksOther laser risksHigh voltageHigh voltageWarning! High voltage capacitorsare ridiculously dangerous things. They can store enough energy toThey can store enough energy to kill you instantly. Retina injured by jystrong laser the person blind ?NoNoNow, a few words about the risk , a few words about the risk laser is a are many types of lamps.

5 The light from a laser has alwaystwo properties: It hasonewavelengthvery narrow bandwidth It has onewavelength very narrow bandwidth It is highlycoherent(well organized, very pure ,intheIt is highly coherent(well organized, very pure , in the same way as the tone from a flute is more pure than the sound of a jet plane).Are these two factors making laser light dangerous?NoFurther, much stronger lasers are used in the ,gfollowing eye treatments:Laser trabeculoplasty for open angle glaucoma Laser iridotomy in pigment dispersion syndromeLaser photocoagulation for neovascular age-related macular degenerationPhotodynamic Therapy of wet macular degenerationLitdiitktili(LASIK)fitiLaser assisted in situ keratomileusis (LASIK) for myopia correctionLaser treatment of diabetic retinopathyLaser treatment of solar retinopathyLaser treatment of age related macular degenerationLaser treatment of age related macular degenerationLasering drusenTreatment of keratoconjunctivitis with LLLTC orrection of myopia (PRK) and astigmatic keratotomy (AK)Correction of myopia (PRK) and astigmatic keratotomy (AK) Laser in transpupillary thermotherapy (TTT))

6 Laser photolysis of cataractLaser welding of the corneaLaser welding of the cornea Laser posterior some other some other treatmentsAlso, it is not "laser" light that may be dangerous. It ili ht ft idtiiIt is any light of certain power, and exposure time, in certain wavelength interval, with certain pulse energy (if pulsed)with certain geometric configuration(if pulsed),with certain geometric configuration (divergence, solid angle) etc that may cause such irradiation in the retina that the MPE (maximum (permissible exposure) is exceeded much of such light sources are IPL, strong flash lamps, certain xenon arc t i th b tt ti?Wh t i th b tt ti?What is the best protection?What is the best protection?Knowledge. Safety glasses can be hazardous: If you use the wrong type, you may think that you are protected, but instead ..CoherencyCoherencyCoherency has nothing to do with parallelism.)

7 Coherency has nothing to do with parallelism. It is often said It is often said th t i lli ht thihth t i lli ht thihhhhbhlhhhbhlthat in laser light, the waves are in phasethat in laser light, the waves are in phasewith each other, but that is only with each other, but that is only true inside the laser cavity. After the light has left the laser, this statement is true inside the laser cavity. After the light has left the laser, this statement is picture is showing light of longThis picture is showing light of long coherence length laserlight .. and ..this picture shows light with pgshorter coherence length -monochromatic ordinary light .Other properties, like parallel beam, high pp, p, gpower may be at hand with some lasers are not strong. Most lasers emit the light in a divergentMost lasers emit the light in a divergent , what makes some lasers dangerous?

8 There are certain risk factors, which?Summary of risk factorsSummary of risk factors1. High powergp2. Long exposure time3. Parallel beam4. Not visible wavelength5. Small beam diameter6 Extreme pulsing (e g Qswitching)6. Extreme pulsing ( Q-switching)1. Extended source / several sources decreases the beam - one of the risk factorsA wide beam is less hazardous to an eye than a narrow beam because only a fraction passes through the pupil, the rest comes of lasers laserClassification of lasers laser classesParameters:Laser type Wavelength Ot tOutput power Divergence Extended source PulsingThe classification of lasers is one of the procedures that are included in the so called CE-approval containing a lot of international lifi d lill b ltf th14A classified laser will belong to one of the groups 1 ,2,3A,3B,41, 2, 3A, 3B,4In Sweden, lasers in these groups are free to use.

9 Doctor ordentistdentistAn eye is working like a digital camera where the retina is a detector matrix with millions of pixels in the form of light sensitive cells. When these cells are hit by visible light, they are producing a nerve signal From this signal our brain is building up an imageproducing a nerve signal. From this signal, our brain is building up an eyeeye lidmuscleThe eyesclerotic coatchoroidirisretinacorneapupiloptic nervefovea (llaqueous humour(yellow spot)AlllbiditdtthtillitWhlki itthmusclescleraA parallel beam is depicted at the retina as a small point. When looking against the sun, the image will be a picture of the sun with sun spots and all. In the case of an unpleasant intensity, our blink reflex is switching off , first by blinking then by turning your as risk factorDifferent ikl lrisk levels in different parts of theparts of the lasers .)

10 Are practically risk free. Fear of laserscause more problemsof laserscause more problems than the lasers themselves do. Therapeutic lasers are usually in the power region 1 - 500 ,.. yes, nobody has become blind from a laser. Any lasers can cure many dieye diseasesLow-Level Laser Therapy Improves Vision in Patients withARltdM l DtiAge-Related Macular DegenerationBoris T. Ivandic, , and Tomislav Ivandic, : LLLT significantly improved visual acuity (p versus baseline) i 162/182 (95%) fithttd 142/146 (97%) fith tin 162/182 (95%) of eyes with cataracts and 142/146 (97%) of eyes without cataracts. The prevalence of metamorphopsia, scotoma, and dyschromatopsia was reduced. In patients with wet AMD, edema and bleeding improved. The improved vision was maintained for 336 months after treatmentimproved vision was maintained for 3 36 months after and Laser SurgeryVolume 26, Number 3, 2008 Volume 26, Number 3, 2008 Mary Ann Liebert, 241 245 Conclusion: lasers are of extremely low risk compared to: Dart gunsAir all b htithf tBroken branches on trees in the us forbid all these things before putting strongLet us forbid all these things before putting strong restrictions on therapeutic (and surgical) lasersThanks for listeningAbout lasers and IPLIn many beauty salons instruments forIn many beauty salons, instruments for permanent removal of hair are used.