Laser therapy began in the 1960s and was initially used in ophthalmology. Aesthetic laser development expanded in the 1980s-2000s to include resurfacing, vascular treatments, and non-ablative options. Lasers are classified by wavelength and pulse duration. Precise targeting relies on chromophore absorption and thermal relaxation time. Risks include eye injury, fire hazards, and airborne particles. Non-ablative options cause minimal downtime while ablative resurfacing has more risks but deeper effects. Fractional resurfacing combines benefits of each. Tattoo removal requires multiple treatments over weeks to slowly break up ink.

1. Laser therapy
Light therapy

2. Laser history
• Theoretical concept 1912, Albert Einstein.
• First working laser, 1960.
• Initially used ophthalmology transparency of tissues clear
view of directed beam.
• Surgical excision and hemostasis.

3. Aesthetic laser
development.
• 80’s resurfacing CO2.
• Early 90’s vascular PDL, argon.
• Mid 90’s resurgent of surfacing laser. CO2, Erbium.
• Late90’s early 2000’s non ablative laser IPL.
• Mid 2000’s present, fractionated laser, Fraxel; fractionated
erbium. Fractionated CO2, fractionated NdYAG,
fractionated RF.

4. Laser Acronyms.
• Laser, light amplification, by stimulated emissions of radiation.
• PDL pulsed dye laser.
• IR infrared
• KTP, Kalium titanyl phosphate.
• LED light emitting diode.
• PDT photodynamic therapy
• IPL intense pulsed light.

5. Lasers classification.
• Wavelength output
• 1064/NdYAG.
• 10,600/ CO2.
• 532/KTP
• Pulse duration, continuous, pulsed: picosecond, Q-
switched nanosecond, long pulse millisecond.

6. Definition
• 1millisecond, 1 thousandth of a second. .001 Sec,
1/1000sec.
• 1 nanosecond, 1 billionth of a sec, 10^-9 sec.
• 1 picosecond, 1 trillionth of a sec, 10^-12 sec

7. Laser physics
• Laser emissions, coherent photons in definite phase
relation.
• Monochromatic single, defined wavelength.
• Collimating, narrow/ low divergent.

8. Laser gain mediums
• Gases CO2, argon, krypton, helium and neon.
• Liquid dye, coumarin, Rhodamine and fluorescein.
• Solid crystal and glasses, neodymium, Nd, yttrium
aluminum garnet YAG, erbium, sapphire ruby, KTP,
potassium titanyl phosphate.

9. Laser light wavelength
output
• Argon, 488,514nm
• KTP, 532nm
• Pulsed due 585,595nm
• Ruby 694nm
• Alexandrite 755nm
• Diode 810nm.
• NdYAG, 1064, 1054, 1320 nm
• Erbium: YAG, 2,940nm
• Erbium:glass 1540, 1550nm
• CO2, 10,600nm
• IPL, 500-1200nm

10. Energy
• Measured in joules.
• Fluence energy delivered per area J/cm2, mJ/cm2.
• Power the rate at which energy is delivered measured in
watt J/sec.

11. Photoselectivity
• Laser or light therapies, photoselectivity.
• Selective photothermolysis, destruction of target without
destruction of surrounding tissues.

12. Thermal effects
• Non selective thermal effects> 100 Celsius, tissues
destruction.
• Selective thermal effect, 45-100 Celsius, protein
denaturation.
• < 45celsius, collagenesis, reversible tissue injury.

13. Non selective thermal
effects
• Too high power or too many passes.
• Non selective thermal damage to tissue outside targe5
area.

14. Non selective thermal
effects
• Scarring.
• Hyperpigmentation/PIH.
• Hypopigmentation.

15. Chromophores
• Chromophores, specific target of a laser, absorbs a
specific laser wavelength.
• Common chromophores in Aesthetic. Water resurfacing,
collagen tightening, melanin hyperpigmentation,
hemoglobin vascular lesions, tattoo ink.

16. Thermal relaxation time.
• TRT, time required for heat energy to dissipate from
chromophores into surrounding tissue.
• Selective photothermolysis requires, all the energy in a
laser pulse must be deievered to a chromophores before
it can release its heat and cool.

17. Photo acoustic
• Mechanical shock wave effect.
• Q switched and picosecond lasers phenomenal only, high
energy released in short duration.
• Tattoo removal breaking up of ink.

18. Wavelength and spot light
• Shorter wavelength, increase melanin absorption.
• Longer wavelength, deeper penetration.
• Increase Spot size, increase pain and discomfort.
• Consider lower fluence with larger spot size.

19. Cooling
• Decrease unintentional injuries. Allows higher fluence.
• Forced cold air, before during after.
• Contact cooling, chilled laser tip.
• Pre and post cooling with copper plate, cooled gel.

20. 4 classes of lasers
• 1 noknown biological hazard
• 2. Chronic viewing hazard.
• 3. Direct viewing hazard.
• 4. Direct and reflected hazard
• Most medical lasers are classes 3 and 4.

21. Eye injury.
• Eyes, most common injury.
• Damage, cornea, lenses, retina.
• Baseline eye exam.

22. Eye injury
• Low divergence, coherent beam, focus on extreme small
spot on retina.
• Wavelength dependent, cornea water, retinal vasculature.

23. Eye injury
• Signs and symptoms injuries
• Flash of light.
• Popping sound follows by disorientation.
• Burning pain in cornea or sclera.
• Retinal damage may not be detected. Lack of pain fibers
in retina,

24. Eye injury.
• Direct laser beam, indirect or reflected laser exposure,
inappropriate eye protection.
• Laser safety eyewear, goggles or glasses. Mandatory use
with all laser procedures.
• Wavelength specific.
• Reduces energy to eye below MPE. Maximum
permissible exposure level.

25. OD optical density
• Ability of a lens to reduce laser energy of a specific wavelength to a
safe level below MPE.
• OD 0 —1,
• OD 1–0.1
• OD 2—0.01
• OD 3–0.001
• OD4—0.0001
• OD5—0.00001 eg OD 5, 1/100,000 original light transmitted.

26. Non laser beam hazards
• Infectious
• Carcinogenic
• Teratogenic
• Papillomavirus cultured from plume CO2.
• Tissue particles splattering Q switched.
• Reports of viral transmission.
• LGAC laser generated air contaminant.

27. Non laser beam hazards
• Prevention
• Smoke evacuation filter < 0.1 micron.
• Masks and gloves laser marks filter smaller particles than
operating room masks.

28. Indirect beam hazard
• Be aware of reflective materials, mirrors and polished
objects.
• Jewelry
• Glossy paint can be a hazard.

29. Fire
• lol laser can ignite.
• Co2 highest risk.
• Direct and reflected beam
• Prevention measures, make sure alcohol prep dry, keep
laser beam away fro gauze, plastic and rubber.

30. Warning labels
• Areas of laser usage must be labeled
• Caution labels for class 1 to 2.
• Danger labels for class 3 to 4.

31. Non ablative rejuvenation
• Creates controlled areas of injury to epidermis and
dermis, destruction of wavelength specific chromophores.
• Most commonly IPL, intense pulse light, BBL broad band
light, photo facial, photo rejuvenation.
• Less commonly laser toning, NdYAG, KTP, PDL.

32. Why non ablative skin
rejuvenation is popular.
• Minimum down time.
• No oozing, swelling, crusting, blistering.
• Mild to moderate erythema 1to 3 hours.

33. Ablative rejuvenation
• Non ablative light therapy
• Chromophores, melanin, hemoglobins, vascular lesions,
thermal effects limited to dermis/ epidermis, collagenesis
leads to heating and remodeling.

34. Pulsed light physics.
• Light source flash lamp.
• BBL, broadband lights, 420-1400nm.
• IPL INTENSE PULSE LIGHT, 500-1200nm.
• Non coherent, non monochromatic, non collimated.
• Not a laser
• Wavelength range selected by changing head or adding
filter.

35. Pulsed light indications
• Pigmentary D/O
• Melasma, solar lentigones, photo damage.
• Vascular lesions: telengiectasia, minor vascular birth
marks.
• Hair removal.
• Photo rejuvenation,

36. Pulsed lights
• Minimal downtime.
• Mild moderate erythema 1 to 3 hrs.
• Dryness, transient hyperpigmentation minor scabbing.
• Requires 2 to 4 sessions for noticeable results.
• Repeat treatment every 2 weeks.

37. Non ablative complications
• PIH, hypopigmentation and scarring.

38. Laser resurfacing ablative.
• Standard resurfacing lasers,
• CO2 10,600 nm.
• Erbium: YAG 2,940nm
• Erbium shallower depth superficial depth.
• Chromophores H2O.

39. Resurfacing
• Indications
• Skin rejuvenation, acne scarring, scarring, rhytids, large
pores, pigmentary disorders and mild skin tightening.

40. Resurfacing
• Mechanism of rejuvenation
• Re epithelialization.
• Collagen deposition.
• Elastin formation.
• Neogenesis.
• Dermis healing phase includes, inflammation, exudate
and crusting.

41. Laser resurfacing.
• Complications:
• PIH.
• Hypopigmentation.
• Scarring.
• Uneven texture.
• Destruction of adnexal tissue.
• Demarcation.
• Prolonged redness.

42. Fractional resurfacing
• MTZ micro thermal zone, minimal damage, micro column
of laser, light to surface of skin, not complete resurfacing.
• Hundreds of MTZ per square cm.

43. Fractional resurfacing
• Normal skin between MTZ, intact epidermis barrier
functions, rapid re-epithelialization, keratinocytes
migration, rapid healing and less risk.

44. Fractional resurfacing
• Minimal down time. Approximately 1 week healing time.
No crusting or oozing, minimal exfoliating.
• New collagen and epithelium per treatment.
• 2007 clinical trail, 5-6 treatments striae improves as much
as 75%.

45. Fractional resurfacing
• Erythema, mild swelling, 1 to 2 days.
• Bronzing/darkening after 2 to 3 days.
• Moderate to severe swelling
• Prednisone 40/30/20/10, step down. Repeats every 4
weeks.

46. Tattoo removal
• End point
• Gray whitening immediate.
• Breaking of ink.
• Follows by erythema and redness, edema, for 3 to 5 days.
• Reaction color dependent, darker color produce more
whitening than lighter color.

47. Tattoo removal
• No ink is removed until 4 weeks.
• Pruritis, peeling, fading @4 weeks.
• No scratching or picking.
• Repeated 6 to 8 weeks, if repeat too short interval
targeting old ink not yet removed.

48. Tattoo removal
• R2, protocol.
• 4 sessions same day, 30 minutes.
• Up to 80- 90% clearance of ink.
• Study done with 2 sessions, 30 minutes apart. Slightly
less ink removal than 4 sessions.
• 70 - 80 % clearance.

49. Laser tattoo removal
• Amateur tattoos easier to remove, shallow ink deposition.
• Less dense, older tattoos easier.

50. Laser tattoo removal
• Wavelength selection, ink color, black, dark brown, red
ink, easiest to remove.
• White, yellow, green, blue, least responsive to laser.

51. Laser tattoo removal
• Q switched, picolaser, photo acoustic, gold standard
short pulse confined energy to small chromophores tattoo
ink and melanin.
• Frequency double, FD, KTP and NdYAG, most versatile,
532–1064.
• New generation triple wavelength picosecond.
532/1064/755expensive. Can remove green and blue ink.

52. Laser tattoo removal.
• FD NdYAG, or picosecond lasers best choice.
• FD NdYAG good for skin type 1 to 5.
• Less melanin absorption at 1064nm than alexandrite 755
nm.

53. General guidelines
• Black, dark blue, 1064 Nd YAG
• Red, orange 532 KTP.
• Blue, green and brown 755 Alexandrite 694 Ruby.

54. Complications
• Permanent darkening metallic pigment in ink.
• Red, white, flesh color, test spot first.
• Ghost image, PIH, hypopigmentation, texture abnormality
and scarring.

55. Laser hair removal
• Anlagen growth phase.
• Cartagen, transition phase.
• Telegen, resting phase.

56. Laser hair removal
• Anagen, growth phase.
• Cartagen transition phase.
• Telegen, resting phase.

57. Laser hair removal
• Anagen phase
• Active growth phase. Approximately 20% of hair.
• Hair follicle most active and most susceptible to
destruction.

58. Laser hair removal
• Non permanent.
• FDA duration 6 months.
• Touch up, or maintenance session 1 to 2 years.

59. Laser hair removal
• Long pulse, NdYAG, 1074nm.
• Penetrates deeper follicle level.
• Good for all skin types. Low absorption, by all 3 major
skin chromophores. H2O, HgB, melanin.
• Alexandrite, 755 nm, one of the first lasers used for hair
removal. Safest for skin types 1 to 3.

60. Laser hair removal
• Diode laser, 810 nm,
• Similar to alexandrite, slightly safer for darker skin types
than alexandrite. Newer generation classification for all
skin types.
• IPL, broadband light, not as specific as laser, more
collateral tissue damage at high settings.

61. Laser hair removal
• Pt selection.
• Light skin and dark hair, optimal results.
• Active tanning, UV exposure, wait for 2 weeks, blonde
hair, no5 good candidate, hypertrichosis, vs hirsuitism
polycystic ovarian syndrome.

62. Laser hair removal
• Average 6 treatments, 4 to 6 weeks apart.
• End point, peri follicular erythema.
• Touch up, or maintainenence session, 1 to 2 years or
when regrowth.
• Result varies among patients and area treated.
• Chin most resistant. Can be 8-9 treatments.

63. General laser contractions
• Isotretinoin/accutane, usage within 1 year, scarring,
• Pregnancy
• Chemical peel, 2 to 4 weeks.
• Waxing within 2 weeks.
• Active herpes simplex.
• Active infection. Bacterial, viral and fungal.
• Systemic corticosteroids.
• Lesions suspicious for malignancy.

64. General resurfacing
complications.
• PIH
• Hypopigmentation
• Scarring.
• Uneven skin tone.
• Demarcation lines.
• Prolonged redness.
• Infection.