13Broadband blue light (400-520 nm) Function and morphology of the retinal pigment epithelium after light-induced damagePurpose: To determine the threshold energy for light-induced functional damage of the retinal pigment epithelium at various wavelengthsBroadband blue light ( nm)Yellow light ( nm)Narrowband blue light (408, 417, 439, 455, 485, 501)58 pigmented rabbit eyes, 21 albino rabbits.Blue light 30 times more efficient than yellow light in causing dysfunction of the blood-retinal barrier.Melanin seemed to play no role. No influence on the threshold energy.
14Endoillumination during vitrectomy and phototoxicity thresholds Br J Ophthalmol 2000;84:1372–1375Not safe with respect to photochemical retinal damageInternational Commission on Non-Ionizing Radiation Protection (ICNIRP)1 min - 10 mm working distance
15CONCLUSIONS: 10 human eyes 6 pig eyes Histology of the Vitreoretinal Interface after Indocyanine Green Staining of the ILM, with Illumination Using a Halogen and Xenon Light Source10 human eyes6 pig eyes3 min light exposure: xenon and halogenCONCLUSIONS:Care should be taken when comparing results obtained in human eyes and porcine eyes.Investigative Ophthalmology and Visual Science. 2005;46:
16Three general mechanisms: Thermal (thermal confinement) Light toxicityThree general mechanisms:Thermal (thermal confinement)Mechanical (stress confinement)Photochemical effects
17Retinal vessel abnormalities of phototoxic retinopathy in rats Progressive loss of outer retinaApproximation deep capillary bedVaso – obliterative changesExtensive pyknosis and reduction of nuclei in the outer nuclear layer, damage to ganglion cells, and edema formation.
18Newer 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).
19Light toxicity and BIOExposure 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
20Long-term follow-up of iatrogenic phototoxicity. Arch Ophthalmol 1998;116:753-7.Iatrogenic phototoxicity following either cataract or vitrectomy surgeryaverage duration of surgery minutes %longer %(Khwarg et all)
213% - 7% of cataract cases (0-28%) Light duration (?) – 11 min 6 patients3% - 7% of cataract cases (0-28%)Light duration (?) – 11 minMcDonald HR, Irvine AR. Light-induced maculopathy from theoperating microscope in the extracapsular cataract extraction and intraocular lens implantation. Ophthalmology. 1983;90:
22Symptomatic vs asymptomatic Visible vs invisible The early finding: deep retinal whitening +/- serous retinal detachmentOval shaped vs round homogenousResolution 48 hours after surgeryMottling RPE in late postopIVFA: window defectAutoflurescence (!)OCTKleinmann G, Hoffman P, Schechtman E, Pollack A. Microscope-induced retinal phototoxicity in cataract surgery of short duration. Ophthalmology. 2002;109:
23OCT Y FOTOTOXICIDAD MACULAR ARCH SOC ESP OFTALMOL 2008; 83:
27Light toxicity in MH surgery In a controlled clinical trial for macular hole repair surgery 7% of patients had presumptive photo- chemical retinal toxicity with a signiﬁcantly 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.
29Iatrogenic phototoxicity during vitrectomy .3 casesone week after surgerysize DD2 eyes fovea sparedMacular phototoxicity caused by fiberoptic endoillumination during pars plana vitrectomy. Am J Ophthalmol Sep 15;114(3):287-96A2e mediated phototoxic effects of endoilluminators, Br. J. Ophthal, 2006Michels M, Lewis H, Abrams GW, et al. Macular phototoxicity caused by fiberoptic endoillumination during pars plana vitrectomy. Am J Ophthalmol 1992; 114: ,
36Predisposing conditions and light toxicity 39 years old FSystemic lupus erythematosus (SLE) + hydroxychloroquine treatmentPhototoxic maculopathy following uneventful cataract surgery in a predisposed patient. Br J Ophthalmol June; 86(6): 705–706
37Phototoxicity to the retina: mechanisms of damage. Int J Toxicol Nov-Dec;21(6):AntibioticsNonsteroidal anti-inflammatory drugs (NSAIDs)Psychotherapeutic agents (Amitrityline, Chlorpromazine, Imipramine, Iprindol, Prozac Thioridazine)Herbal medicine
38D/DApplying aspiration to macular holes for drying purposes when using adjuvantsICG and other dyes used to visualize the ILMAminoglycoside antibiotic toxicityUnrecognized mechanical trauma to RPE
39Light toxicity and ICG assisted ILM peeling 72 years old manMH stage IIIXenotron II, Geuder, Germany2 times 0.05 % ICG10-15 attempts – 10 min + 2 minPost op: MH closedVis 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
41Banker AS, Freeman WR, Kim JW, Munguia D, Azen SP 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
42SURGICAL CONSIDERATIONS Any illumination system can be phototoxic, therefore usually precautoins apply.Surgical time shortened (?)Various filters are introduced during surgery.Try to vary the directionality and intensity of light throughout the case; combining diffuse and tangential "spot" lightingNo use illuminated forceps or scissors in macular surgery (small gauge surgery)
44Xenon BrightStar - 1266-XIII, DORC 420nm cut-off: standard435nm cut-off: for core vitrectomy and general membrane removal475nm cut-off: for removal of membranes adherent to the retina515nm cut-off: for macular repair
45SURGICAL CONSIDERATIONS Illuminating just the area between the vascular arcades, which has a diameter of about 10 mm, would correspond with a ﬁbre- optic distance of only 5 mmMinimize the time that the fiber optic tip is less than 8-10 mm from the retinal surfaceNot to use the light probe as an instrument to manipulate the detached retina (photochemical damage)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
47SURGICAL CONSIDERATIONS Use of intraoperative dyes, such as indocyanine green, or systemic medications, such as tetracycline, may alter the threshold for damage.Be aware of the output power from the fiber optic; ideally aim for mW.Power output range from 24 lumens for stiff 25- gauge light probes to over 80 lumens on some chandeliers.Remember that a fresh bulb will increase the power output.Surgical video!
49Application 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)
50A, Removal of the vitreous gel (4500 lux) 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).