Retina Sessions I.M.O 2009 Leyla Asgarova, MD Illumination and light toxicity in vitreoretinal...

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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

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

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 and ECCE

Light toxicity in MH surgery

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

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

Decreasing in size – 21%

No correlation age - visual outcome. (VO)

change in lesion size - VO

Symptomatic – 33%

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.

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

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:

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

Retina Sessions I.M.O 2009 Leyla Asgarova, MD Illumination and light toxicity in vitreoretinal...

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