Download Light toxicity - Punto de Encuentro Oftalmológico

Retina Sessions
I.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
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Focal
Diffuse
Specular
Retroillumination
Slitlamp attachment for the OM
Evolutionary and Revolutionary Trends in Vitreoretinal Surgery
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Bullet light probes
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Shielded bullet probes (provide up to 180Þ of illumination
while controlling glare)
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Chandelier lighting systems
ILLUMINATED INSTRUMENTS, CHANDELIER LIGHTING
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Dual-mode cannula
Tornambe Torpedo (Insight Instruments, Stuart, Fla)
Synergetics Awh Chandelier
Tissue manipulator
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Viscodelamination light probes
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Evolutionary and Revolutionary Trends in Vitreoretinal Surgery
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Tungsten halogen system
Alcon Accurus: Fort Worth, Texas
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Short-arc Xenon illumination system:
Alcon Accurus
Synergetics’ Photon box (O’Fallon, Mo)
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Metal halide system
Millennium, Bausch & Lomb, (Rochester, N.Y.)
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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
Br J Ophthalmol 2000;84:1372–1375

Not safe with respect to photochemical retinal damage

International Commission on Non-Ionizing Radiation
Protection (ICNIRP)
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1 min - 10 mm working distance
Histology of the Vitreoretinal Interface after Indocyanine Green Staining of
the ILM, with Illumination Using a Halogen and Xenon Light Source
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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:
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Thermal (thermal confinement)
Mechanical (stress confinement)
Photochemical effects
Retinal vessel abnormalities of phototoxic retinopathy in rats
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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
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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.
Arch Ophthalmol 1998;116:753-7.

Iatrogenic phototoxicity following either cataract or
vitrectomy surgery
average duration of surgery - 109 minutes - 0.9%
longer - 39%
(Khwarg et all)
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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.
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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
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In a controlled clinical trial for macular hole repair
surgery 7% of patients had presumptive photochemical 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
.
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3 cases

one week after
surgery
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size - 2-5 DD
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2 eyes fovea
spared
Macular phototoxicity caused by fiberoptic endoillumination during pars plana vitrectomy.
Am J Ophthalmol. 1992 Sep 15;114(3):287-96
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; 114:287-96.,
Xenon light induced phototoxicity lesions
Arch Soc Espanola de Oftalmologia, Febr 2000
Xenon light induced phototoxicity lesions
Long-term Follow-up of Iatrogenic Phototoxicity
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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
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Decreasing in size – 21%
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No correlation age - visual outcome. (VO)
change in lesion size - VO
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Symptomatic – 33%
Long-term Follow-up of Iatrogenic Phototoxicity
Predisposing conditions and
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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.
Int J Toxicol. 2002 Nov-Dec;21(6):473-90.
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Antibiotics
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Nonsteroidal anti-inflammatory drugs (NSAIDs)
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Psychotherapeutic agents (Amitrityline,
Chlorpromazine, Imipramine, Iprindol, Prozac
Thioridazine)
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Herbal medicine
D/D
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Applying aspiration to macular holes for drying
purposes when using adjuvants
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ICG and other dyes used to visualize the ILM
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Aminoglycoside antibiotic toxicity
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Unrecognized mechanical trauma to RPE
Light toxicity and ICG assisted ILM peeling
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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 greenassisted 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
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Any illumination system can be phototoxic, therefore usually
precautoins apply.
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Surgical time shortened (?)
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Various filters are introduced during surgery.
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Try to vary the directionality and intensity of light throughout the
case; combining diffuse and tangential "spot" lighting
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No use illuminated forceps or scissors in macular surgery (small
gauge surgery)
To reduce the risk of retinal phototoxicity:
Xenon BrightStar - 1266-XIII,
DORC
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420nm cut-off: standard
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435nm cut-off: for core
vitrectomy and general
membrane removal
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475nm cut-off: for removal of
membranes adherent to the
retina
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515nm cut-off: for macular
repair
SURGICAL CONSIDERATIONS
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Illuminating just the area between the vascular arcades, which
has a diameter of about 10 mm, would correspond with a fibreoptic distance of only 5 mm
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Minimize the time that the fiber optic tip is less than 8-10 mm
from the retinal surface
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Not to use the light probe as an instrument to manipulate the
detached retina (photochemical damage)
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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
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Use of intraoperative dyes, such as indocyanine green, or
systemic medications, such as tetracycline, may alter the
threshold for damage.
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Be aware of the output power from the fiber optic; ideally aim for
10-20 mW.
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Power output range from 24 lumens for stiff 25- gauge light
probes to over 80 lumens on some chandeliers.
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Remember that a fresh bulb will increase the power output.
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Surgical video!
GRACIAS
Festival Grec
Ennogata, Sylvie Guillem
July 2009