Presentation on theme: "Retina Sessions I.M.O 2009 Leyla Asgarova, MD Illumination and light toxicity in vitreoretinal surgery."— Presentation transcript:
Retina Sessions I.M.O 2009 Leyla Asgarova, MD Illumination and light toxicity in vitreoretinal surgery
Light toxicity u Verhoeff, 1916 u Noell, 1966 u Light source intensity u Spectral content of the light u Exposure time
u Focal u Diffuse u Specular u Retroillumination u Slitlamp attachment for the OM
Evolutionary and Revolutionary Trends in Vitreoretinal Surgery u Bullet light probes u Shielded bullet probes (provide up to 180Þ of illumination while controlling glare) u Chandelier lighting systems
ILLUMINATED INSTRUMENTS, CHANDELIER LIGHTING u Dual-mode cannula u Tornambe Torpedo (Insight Instruments, Stuart, Fla) u Synergetics Awh Chandelier u Tissue manipulator u Viscodelamination light probes
Evolutionary and Revolutionary Trends in Vitreoretinal Surgery u Tungsten halogen system Alcon Accurus: Fort Worth, Texas u Short-arc Xenon illumination system: Alcon Accurus Synergetics Photon box (OFallon, Mo) u Metal halide system Millennium, Bausch & Lomb, (Rochester, N.Y.) u Mercury vapor
Evolutionary and Revolutionary Trends in Vitreoretinal Surgery
Spectral content of the light
Function and morphology of the retinal pigment epithelium after light-induced damage u Purpose: To determine the threshold energy for light-induced functional damage of the retinal pigment epithelium at various wavelengths u Broadband blue light ( nm) Yellow light ( nm) Narrowband blue light (408, 417, 439, 455, 485, 501) u 58 pigmented rabbit eyes, 21 albino rabbits. u Blue light 30 times more efficient than yellow light in causing dysfunction of the blood-retinal barrier. u Melanin seemed to play no role. No influence on the threshold energy.
Endoillumination during vitrectomy and phototoxicity thresholds u Not safe with respect to photochemical retinal damage u International Commission on Non-Ionizing Radiation Protection (ICNIRP) u 1 min - 10 mm working distance Br J Ophthalmol 2000;84:1372–1375
Histology of the Vitreoretinal Interface after Indocyanine Green Staining of the ILM, with Illumination Using a Halogen and Xenon Light Source u 10 human eyes u 6 pig eyes u 3 min light exposure: xenon and halogen CONCLUSIONS: Care should be taken when comparing results obtained in human eyes and porcine eyes. Investigative Ophthalmology and Visual Science. 2005;46:
Light toxicity Three general mechanisms: u Thermal (thermal confinement) u Mechanical (stress confinement) u Photochemical effects
Retinal vessel abnormalities of phototoxic retinopathy in rats u Progressive loss of outer retina u Approximation deep capillary bed u Vaso – obliterative changes u Extensive pyknosis and reduction of nuclei in the outer nuclear layer, damage to ganglion cells, and edema formation.
Newer Endoilluminators Ease 25-Gauge Surgery (Retina today, Allen C) Normal and 1.5-hour light exposed retina with a fixed position endoilluminator. Images show a normal rabbit retina (A), a Tungsten-halogen exposed retina (B), a xenon-bipass exposed retina (C) and a metal-halide exposed retina (D).
Light toxicity and BIO u Exposure to the indirect ophthalmoscope for more than 15 minutes is necessary to cause retinal lesions. Robertson DM, Erickson GJ. The effect of prolonged indirect ophthalmoscopy on the human eye. Am J Ophthalmol 1979;87: Ts'o MOM, Fine BS, Zimmerman LE. Photic maculopathy produced by the indirect ophthalmoscope. 1. Clinical and histopathologic study. Am J Ophthalmol 1972
Long-term follow-up of iatrogenic phototoxicity. u Iatrogenic phototoxicity following either cataract or vitrectomy surgery average duration of surgery minutes - 0.9% longer - 39% (Khwarg et all) Arch Ophthalmol 1998;116:753-7.
u 6 patients u 3% - 7% of cataract cases (0-28%) u Light duration (?) – 11 min McDonald HR, Irvine AR. Light-induced maculopathy from theoperating microscope in the extracapsular cataract extraction and intraocular lens implantation. Ophthalmology. 1983;90:
u Symptomatic vs asymptomatic u Visible vs invisible u The early finding: deep retinal whitening +/- serous retinal detachment u Oval shaped vs round homogenous u Resolution 48 hours after surgery u Mottling RPE in late postop u IVFA: window defect u Autoflurescence (!) u OCT Kleinmann G, Hoffman P, Schechtman E, Pollack A. Microscope-induced retinal phototoxicity in cataract surgery of short duration. Ophthalmology. 2002;109:
OCT Y FOTOTOXICIDAD MACULAR ARCH SOC ESP OFTALMOL 2008; 83:
Light toxicity after cataract surgery
Light toxicity and ECCE
Light toxicity in MH surgery u In a controlled clinical trial for macular hole repair surgery 7% of patients had presumptive photo- chemical retinal toxicity with a signicantly worse visual outcome. Banker AS, Freeman WR, Kim JW, et al. Vision-threating complications of surgery for full-thickness macular holes. Ophthalmology 1997;104:1442–53.
Light toxicity by fiber light probe
Iatrogenic phototoxicity during vitrectomy u 3 cases u one week after surgery u size DD u 2 eyes fovea spared. Macular phototoxicity caused by fiberoptic endoillumination during pars plana vitrectomy. Am J Ophthalmol Sep 15;114(3): A2e mediated phototoxic effects of endoilluminators, Br. J. Ophthal, 2006 Michels M, Lewis H, Abrams GW, et al. Macular phototoxicity caused by fiberoptic endoillumination during pars plana vitrectomy. Am J Ophthalmol 1992; 114: ,
Long-term Follow-up of Iatrogenic Phototoxicity u 24 eyes (20 ant. segment surgeries, 4 – vitrectomy) u min, aver. surgical time min. u Follow-up - 34 months u Lesions spared to fovea – ant. segment surgeries involved fovea – after vitrectomy u Inferior the fovea – 9 superior – 5 20/20 – 20/25 temporal – 3 subfoveal /400 Arch Ophthal, Vol. 116 No. 6, June 1998
Long-term Follow-up of Iatrogenic Phototoxicity
u Decreasing in size – 21% u No correlation age - visual outcome. (VO) change in lesion size - VO u Symptomatic – 33%
Long-term Follow-up of Iatrogenic Phototoxicity
Predisposing conditions and light toxicity u 39 years old F u Systemic lupus erythematosus (SLE) + hydroxychloroquine treatment Phototoxic maculopathy following uneventful cataract surgery in a predisposed patient. Br J Ophthalmol June; 86(6): 705–706
Phototoxicity to the retina: mechanisms of damage. u Antibiotics u Nonsteroidal anti-inflammatory drugs (NSAIDs) u Psychotherapeutic agents (Amitrityline, Chlorpromazine, Imipramine, Iprindol, Prozac Thioridazine) u Herbal medicine Int J Toxicol Nov-Dec;21(6):
D/D u Applying aspiration to macular holes for drying purposes when using adjuvants u ICG and other dyes used to visualize the ILM u Aminoglycoside antibiotic toxicity u Unrecognized mechanical trauma to RPE
Light toxicity and ICG assisted ILM peeling u 72 years old man u MH stage III u Xenotron II, Geuder, Germany u 2 times 0.05 % ICG u attempts – 10 min + 2 min u Post op: MH closed u Vis postop – HM + centra (12 weeks) Severe retinal damage after macular hole surgery with extensive indocyanine green- assisted internal limiting membrane peeling (Eye (2004) 18, 538–539
Banker AS, Freeman WR, Kim JW, Munguia D, Azen SP. Vision-threatening complications of surgery for full-thickness macular holes. Vitrectomy for Macular Hole Study Group. Ophthalmology 1997; 104: 1442–1452
SURGICAL CONSIDERATIONS u Any illumination system can be phototoxic, therefore usually precautoins apply. u Surgical time shortened (?) u Various filters are introduced during surgery. u Try to vary the directionality and intensity of light throughout the case; combining diffuse and tangential "spot" lighting u No use illuminated forceps or scissors in macular surgery (small gauge surgery)
To reduce the risk of retinal phototoxicity:
Xenon BrightStar XIII, DORC u 420nm cut-off: standard u 435nm cut-off: for core vitrectomy and general membrane removal u 475nm cut-off: for removal of membranes adherent to the retina u 515nm cut-off: for macular repair
SURGICAL CONSIDERATIONS u Illuminating just the area between the vascular arcades, which has a diameter of about 10 mm, would correspond with a bre- optic distance of only 5 mm u Minimize the time that the fiber optic tip is less than 8-10 mm from the retinal surface u Not to use the light probe as an instrument to manipulate the detached retina (photochemical damage) u Exposure to the operating microscope light should be minimized as much as possible by either turning off the illumination source or placing a small shield or cover on the cornea when not using the microscope
To reduce the risk of retinal phototoxicity:
SURGICAL CONSIDERATIONS u Use of intraoperative dyes, such as indocyanine green, or systemic medications, such as tetracycline, may alter the threshold for damage. u Be aware of the output power from the fiber optic; ideally aim for mW. u Power output range from 24 lumens for stiff 25- gauge light probes to over 80 lumens on some chandeliers. u Remember that a fresh bulb will increase the power output. u Surgical video!
GRACIAS Festival Grec Ennogata, Sylvie Guillem July 2009
Application of a Newly Developed, Highly Sensitive Camera and a 3- Dimensional High-Definition Television System in Experimental Ophthalmic Surgeries (Arch Ophthal. 1999, 117, 1623 – 1629)
A, Removal of the vitreous gel (4500 lux). B, Procedures during "back flash" technique for creating posterior vitreous detachment (14,700 lux). C, Membrane peeling. Note the fine fibrous tissue (8900 lux). D, Membrane peeling (6300 lux).