LASER LASERS AND LATTE Richard G. Orlando, M.D., F.A.C.S. Light Amplification by Stimulated Emission of Radiation Photons are in phase to produce high intensity polarized light Modification by shutters and filters that alter the energy Various gases are used to create this energy Deep UV damage is caused by the laser energy LASERS IN EYE CARE POLL QUESTION Based on Einstein s theory of stimulated emission of radiation First attempts were with a Ruby laser on animals in early 1960 s with very deep burns and intense scarring with poor photocoagulation due to the red wave-length of light which was not absorbed by by blood The argon laser was discovered in the late 60 s and produced a blue/green wavelength. This was strongly absorbed by hemoglobin and melanin. Coherant, Inc refined the delivery system and brought this to market in early 70 s. It remained the mainstay for modern photocoagulation for 35 years Changes in the gases used, delivery systems and ultra-short pulses of energy have provided a wide variety of clinical uses Laser energy is commonly produce by A) Heat related energy B) Concussive energy C) Sound waves D) All of the above THE ARGON LASER DIABETIC RETINOPATHY Uses Argon Fluoride gas as the energy source Closes leaking blood vessels A hot laser that causes thermal damage Destroys normal retinal tissue in order to decrease neovascularization Used to cauterize and destroy tissue Can be localized treatment or pan retinal photocoagulation Has a wide beam and therefore can damage normal cells Abnormal vessels will regress over several months and reduce risk of bleeding into the vitreous 1
DIABETIC RETINOPATHY RETINAL VEIN OCCLUSION Focal Treatment Pan Retinal Treatment Focal treatment will allow regression of neovascular changes RETINAL TEARS CARBON DIOXIDE ( CO2) LASER Seals retinal pigment around tear and prevents progression of detachment Preventive treatment for high risk patients such as lattice degeneration CO2 gas is the energy source Infrared laser that has high absorption of heat Excellent for incisions and excisions as it reduces bleeding Surgeon, staff and patient all need protection to prevent retinal damage Need Laser In Use sign on OR door so no one enters the room USE IN OCULO-PLASTIC SURGERY BLEPHAROPLASTY For blepharoplasty, it improves visualization of underlying tissue due to excellent hemostasis and precise incisions Reduced OR time with less bleeding and edema Standard of care to remove hemangiomas and vascular tumors Rapid recovery with less pain and swelling Sculpts orbital fat reducing chance of lid retraction in lower lid procedures 2
BROW PTOSIS/BLEPHAROPLASTY LID AND FACIAL SURGERY Less damage to healthy tissue when used for skin resurfacing and wrinkle removal Better results with faster recovery over dermabrasion and chemical peels UPPER AND LOWER LID SURGERY ND:YAG LASER Neodynium Doped Yittrium Aluminum Garnett crystal energy Solid state laser that is a pulsed cold laser Creates an acoustic shock wave Can cut transparent tissue as it does not need to be absorbed CAPSULOTOMY Posterior capsular opacification Anterior capsular shrinkage 3
CUTTING OF VITREOUS STRANDS PERIPHERAL IRIDOTOMY POLL QUESTION SLT LASER The first line of treatment in my practice for open angle glaucoma is A frequency doubled ND:YAG Laser A) SLT laser Short Pules with low energy.. A cold laser B) Topical drops Target is melanin containing cells of the trabecular meshwork C) Dependant on the clinical circumstances Far less traumatic than argon laser which damages healthy cells thus the name Selective Laser Trabeculoplasty Open Angle Glaucoma SLT LASER USES IN EYE CARE Pigmentary Glaucoma Pseudo-Exfoliation Glaucoma 4
PRIMARY TREATMENT WITH SLT Lowers IOP 6-8mmHg within 6 weeks Useful for patients that have difficulty using drops such as those with Parkinson s or arthritis Best option for non compliant patients or those with dementia SLT RESULTS Can have IOP spike in first hour Average effect lasts five years Can repeat SLT if patient had good initial response If not a good response with first treatment then will need filtering procedure EXCIMER LASER Excited Dimer Laser A UV laser with an excited dimer complex Uses noble gas halides such as xenon, argon or krypton Reactive gas helps excites the proton: fluorine or chlorine This reaction creates a pseudo molecule or dimer The dimer causes a uniform beam of UV laser energy This is well abosrbed by organic tissue Can be applied to very thin tissue without surrounding damage Cuts transparent tissue Ablates tissue but does not burn it.a cold laser 5
USES IN EYE CARE OTHER MEDICAL APPLICATIONS Excellent results with treating vitiligo Lasik using a micro keratome PRK Correction of corneal astigmatism POLL QUESTION FEMTO LASER TECHNOLOGY It is easy for me to distinguish the difference between a femto created lasik flap versus a micro keratome flap at the slit lamp A) Yes B) No INFRARED LASER WITH ND:YAG ENERGY SOURCE FEMTO LASIK SURGERY Ultrafast pulses ( thus femto ) reduces damage 100 times less than ND:YAG Energy delivered in acoustic shock wave that causes plasma formation Cavitation bubbles are created and separate tissue in a precise manner Cuts transparent tissue easily and safely at the micron level LAser In Situ Keratomileusis Predictable, thinner flaps leaves more corneal tissue Thickness is the same so less aberrations Can treat refractive errors from -12 to + 6 Less need for retreatment compared to excimer alone 6
VERY CLEAN CUT OF THE FLAP CORNEAL INLAY FOR PRESBYOPIA Can create tunnel Can create flap if RS necessary POLL QUESTION FEMTO ASSISTED CATARACT Femto assisted cataract is currently being done on only 10% of all patients in the US. What are the factors that keep that number so low Requires docking on the cornea cannot use if K s greater than 46 or with corneal scarring A) Lack of precision B) Costs of the laser and maintenance C) High learning curve for surgeons D) Lack of access to the laser E) Not a significant part of surgical training programs Mapping used to center the laser with 3d or OCT technology Can create arcuate incisions for astigmatism at 80% depth Creates 5 mm capsulorrhexis DIVIDES NUCLEUS INTO 4, 6 OR 8 SECTIONS IN 30-45 SECONDS Corneal incisions then created all outside the operating room Patient then moved to OR for phaco and IOL insertion PROS OF FEMTO ASSISTED CATARACT More accurate incisions for astigmatism Pre-chopping of nucleus reduces phaco energy Computer generated incision depth 7
CONS OF LASER ASSISTED PHACO ZEPTO CAPSULORRHEXIS DEVICE Corneal docking can be difficult in certain patients High speed energy system delivers electrical impulses to lens capsule Not useful in small pupil cases or white cataract Vaporizes clear tissue so may have more applications in the future Higher costs and longer OR time Steep learning curve with results clinical results the same as phaco for routine case With smaller lasers attached to microscope, lower initial costs and expanded use in ophthalmology training programs this technology will gain more acceptance Disposable single use cannula creates perfect 5mm capsule Far less expensive than Femto laser with more applications as it can be used with corneal scarring, white cataracts and small pupil cases ZEPTO CANNULA ZEPTO CANNULA FORCEPS CANNULA Use in standard cataract Use in morgagnian cataract FUTURE CONSIDERATIONS SUMMARY: LASERS IN EYECARE Laser technology has been used in eye care for over 40 years Future applications will reduce costs and improve efficiency Femto will become more mainstream once costs come down and the laser becomes part of the surgical microscope or phaco system Argon- Retinal vascular disease CO2- Oculo- plastic surgery ND:YAG- Post cataract opacification and narrow angle glaucoma SLT- Open angle glaucoma Excimer-PRK and vitiligo Femto- LASIK and Laser Assisted Cataract Surgery ( LACS) Zepto technology will be utilized more in various forms as R and D continues 8