9.12.3  Scope

Destruction of small to medium tumors, and residual tumors after chemoreduction and recurrences, particularly posterior to the equator.

response for that machine) at which no visible effect is apparent. Laser is applied to the entire tumor surface at selected power setting.

−−Infrared laser may also be delivered to the peripheral tumors through a transcleral optical probe while observing the whitening effect through the pupil.

9.12.4  Clinical Significance

Laser light can physically destroy the viable tissue and tumor by heat; lower wavelength light (532-nm or Argon-green) penetrates less deeply, while infrared (810-nm, Diode) or far infrared (1,021-nm, YAG) penetrate more deeply.

9.12.5  Procedure

•Green laser (argon or 532-nm frequency doubleYAG):

−−Used to coagulate residual or recurrent tumors up to 3-mm thick, particularly posterior to the equator. Each tumor requires repeated laser application on several sessions.

−−Repeated burns of 50–500 µm are placed in the retina immediately around small newly diagnosed tumors, by indirect ophthalmoscopy through a widely dilated pupil.

−−Subsequent burns are applied directly to the tumor surface initially at a low energy output (50 mW) with a burn-duration of 400 ms, and then the power is gradually increased to achieve gentle whitening of each spot.

•Infrared lasers (810-nm diode laser and 1,064-nm continuous-wave YAG laser used interchangeably):

−−Best for treating tumors up to 4 mm thick.

−−Using operating microscope or indirect ophthalmoscope, a >500 µm-spot is applied directly to the tumor.

−−Diode laser starting at low power (600 mW) with up to 1-s duration (usually 3,000 ms) is delivered, with the power gradually increased till slight whitening of the tumor is observed.

−−1,064-nm laser is delivered in 1-s duration burns, at a constant power (adjusted to a subclinical

9.12.6  Consequences

•Inadequate laser treatment results in failure to control the tumor.

•Complete response is often seen as a flat residual mass with white, gliotic appearance devoid of tumor vessels.

•Retreating a gliotic scar may result in increased gliosis with vitreous traction.

•Diode laser may produce scars that extend and produce traction over time [42, 43].

•Excessive laser energy can cause complications: hemorrhage, tumor disruption, break in inner limiting membrane, or vitreous seeding.

•Lasering through inadequately dilated pupil causes iris burns, pupil deformity, or cataract.

9.12.7  Related SOPs

OPHTH laser 532; OPHTH laser 810; OPHTH laser 1021.

9.13  Local Chemotherapy SOP

9.13.1  Objectives

Used alone or as adjunct to systemic chemotherapy to increase the intravitreal carboplatin concentration [44].

9.13.2  Applicability

Ophthalmologist, oncologist