Retina SessionsI.M.O 2009
Leyla Asgarova, MD
Illumination and light toxicity in
vitreoretinal surgery
Light toxicity
Verhoeff, 1916 Noell, 1966
Light source intensity Spectral content of the light Exposure time
Focal Diffuse Specular Retroillumination Slitlamp attachment for the OM
Evolutionary and Revolutionary Trends in Vitreoretinal Surgery
Bullet light probes
Shielded bullet probes (provide up to 180Þ of illumination
while controlling glare)
Chandelier lighting systems
ILLUMINATED INSTRUMENTS, CHANDELIER LIGHTING
Dual-mode cannula Tornambe Torpedo (Insight Instruments, Stuart, Fla) Synergetics Awh Chandelier Tissue manipulator Viscodelamination light probes
Evolutionary and Revolutionary Trends in Vitreoretinal Surgery
Tungsten halogen system Alcon Accurus: Fort Worth, Texas
Short-arc Xenon illumination system: Alcon Accurus Synergetics’ Photon box (O’Fallon, Mo)
Metal halide system Millennium, Bausch & Lomb, (Rochester, N.Y.)
Mercury vapor
Evolutionary and Revolutionary Trends in Vitreoretinal Surgery
Evolutionary and Revolutionary Trends in Vitreoretinal Surgery
Evolutionary and Revolutionary Trends in Vitreoretinal Surgery
Spectral content of the light
Spectral content of the light
Function and morphology of the retinal pigment epithelium after light-induced damage
Purpose: To determine the threshold energy for light-induced functional damage of the retinal pigment epithelium at various wavelengths
Broadband blue light (400-520 nm) Yellow light (510-740 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.
Endoillumination during vitrectomy and phototoxicity thresholds
Not safe with respect to photochemical retinal damage
International Commission on Non-Ionizing Radiation Protection (ICNIRP)
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
10 human eyes 6 pig eyes 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;46:1468-1472
Light toxicity
Three general mechanisms:
Thermal (thermal confinement) Mechanical (stress confinement) Photochemical effects
Retinal vessel abnormalities of phototoxic retinopathy in rats
Progressive loss of outer retina Approximation deep capillary bed Vaso – obliterative changes 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
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;87:652-661.
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.
Iatrogenic phototoxicity following either cataract or vitrectomy surgery
average duration of surgery - 109 minutes - 0.9%
longer - 39%
(Khwarg et all)
Arch Ophthalmol 1998;116:753-7.
6 patients 3% - 7% of cataract cases (0-28%) 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;90:945-951.
Symptomatic vs asymptomatic Visible vs invisible The early finding: deep retinal whitening +/- serous
retinal detachment Oval shaped vs round homogenous Resolution 48 hours after surgery Mottling RPE in late postop IVFA: window defect Autoflurescence (!) OCT
Kleinmann G, Hoffman P, Schechtman E, Pollack A. Microscope-induced retinal phototoxicity in cataract surgery of short duration. Ophthalmology. 2002;109:334-338.
OCT Y FOTOTOXICIDAD MACULAR
ARCH SOC ESP OFTALMOL 2008; 83: 267-272
Light toxicity after cataract surgery
Light toxicity after cataract surgery
Light toxicity and ECCE
Light 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.
Light toxicity by fiber light probe
Iatrogenic phototoxicity during vitrectomy
3 cases
one week after surgery
size - 2-5 DD
2 eyes fovea spared
.
Macular phototoxicity caused by fiberoptic endoillumination during pars plana vitrectomy.Am J Ophthalmol. 1992 Sep 15;114(3):287-96A2e 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; 114:287-96.,
Xenon light induced phototoxicity lesions
Arch Soc Espanola de Oftalmologia, Febr 2000
Xenon light induced phototoxicity lesions
Long-term Follow-up of Iatrogenic Phototoxicity
24 eyes (20 ant. segment surgeries, 4 – vitrectomy) 50-220 min, aver. surgical time - 109 min. Follow-up - 34 months Lesions spared to fovea – ant. segment surgeries
involved fovea – after vitrectomy Inferior the fovea – 9
superior – 5 20/20 – 20/25
temporal – 3
subfoveal - 5 20/400
Arch Ophthal, Vol. 116 No. 6, June 1998
Long-term Follow-up of Iatrogenic Phototoxicity
Long-term Follow-up of Iatrogenic Phototoxicity
Decreasing in size – 21%
No correlation age - visual outcome. (VO)
change in lesion size - VO
Symptomatic – 33%
Long-term Follow-up of Iatrogenic Phototoxicity
Predisposing conditions and light toxicity
39 years old F Systemic lupus erythematosus (SLE) + hydroxychloroquine
treatment
Phototoxic maculopathy following uneventful cataract surgery in a predisposed patient. Br J Ophthalmol. 2002 June; 86(6): 705–706
Phototoxicity to the retina: mechanisms of damage.
Antibiotics
Nonsteroidal anti-inflammatory drugs (NSAIDs)
Psychotherapeutic agents (Amitrityline, Chlorpromazine, Imipramine, Iprindol, Prozac Thioridazine)
Herbal medicine
Int J Toxicol. 2002 Nov-Dec;21(6):473-90.
D/D
Applying aspiration to macular holes for drying purposes when using adjuvants
ICG and other dyes used to visualize the ILM
Aminoglycoside antibiotic toxicity
Unrecognized mechanical trauma to RPE
Light toxicity and ICG assisted ILM peeling
72 years old man MH stage III Xenotron II, Geuder, Germany 2 times 0.05 % ICG 10-15 attempts – 10 min + 2 min Post op: MH closed 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
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" lighting
No use illuminated forceps or scissors in macular surgery (small gauge surgery)
To reduce the risk of retinal phototoxicity:
Xenon BrightStar - 1266-XIII, DORC
420nm cut-off: standard
435nm cut-off: for core vitrectomy and general membrane removal
475nm cut-off: for removal of membranes adherent to the retina
515nm cut-off: for macular repair
SURGICAL 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 mm
Minimize the time that the fiber optic tip is less than 8-10 mm from the retinal surface
Not 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
To reduce the risk of retinal phototoxicity:
SURGICAL 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 10-20 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!
GRACIAS
Festival GrecEnnogata, Sylvie GuillemJuly 2009