 |
| UNIVERSITY OPHTHALMOLOGY CONSULTANTS |
|
WHAT
IS LASER SURGERY?
Lasers
generate light of a particular wavelength. The absorption
of laser light by tissue generates heat which causes
molecular denaturation and necrosis in the absorbing
and surrounding tissue. In the case of proliferative
diabetic retinopathy, laser photocoagulation
may induce a therapeutic effect by destroying outer
retinal tissue (for example, photoreceptors), thus reducing
the oxygen requirements of the retina, and/or by increasing
oxygen delivery to the remaining retina through alterations
in oxygen diffusion from the choroid. In the case of
macular edema,
laser treatment may result in obliteration of the leaking
vascular structures and/or in reflex vasoconstriction
with decreased fluid delivery to the treated area. In
the case of choroidal
neovascularization, laser treatment
may induce thrombosis of the abnormal vessels and/or
may induce treated RPE cells to elaborate inhibitors
of neovascularization (a mechanism that also may operate
in the treatment of retinal
neovascularization).
The most commonly used lasers include the 1) Nd:YAG,
which is used in the disruption of "after-cataract"
(YAG capsulotomy), peripheral iridectomy, lysis of fibrotic
tissue (in the anterior or posterior segment), lysis
of vitreoretinal adhesions (in selected cases); 2) argon
blue-green, which is restricted to treatment
outside the foveal avascular zone (FAZ); 3) argon
green, used inside or outside the FAZ;
4) krypton red,
which allows better penetration through lens opacities,
mild vitreous hemorrhage, and thin subretinal blood
than argon; 5) and organic
dye laser, which has various wavelengths,
including yellow, orange, and red.
Dye yellow is useful when coagulating a blood-containing
lesion that contains little pigment especially if the
media is hazy. It may be useful in treating microaneurysms
and macroaneurysms, retinal neovascularization (direct
vessel closure), and telangiectatic retinal vessels
(for example, in Coats' retinopathy). Orange may be
useful for treating choroidal new vessels (CNVs), angiomatosis
retinae, choroidal hemangioma, advanced retinal telangiectasia,
and direct retinal vascular closure (for example, feeder
vessel closure). Red may be useful for treating CNVs
(due to choroidal and RPE melanin content), panretinal
photocoagulation with minimal vitreous hemorrhage or
with intraretinal hemorrhage, as well as structural
retinal defects (for example, tears, lattice degeneration).
Some side effects of laser surgery include decreased
central vision, decreased peripheral and/or night vision,
and scotomata (blind spots) in the treated area.
| WHAT IS LASER SURGERY? | ||
|
Lasers generate light of a particular wavelength. The absorption of laser light by tissue generates heat which causes molecular denaturation and necrosis in the absorbing and surrounding tissue. In the case of proliferative diabetic retinopathy, laser photocoagulation may induce a therapeutic effect by destroying outer retinal tissue (for example, photoreceptors), thus reducing the oxygen requirements of the retina, and/or by increasing oxygen delivery to the remaining retina through alterations in oxygen diffusion from the choroid. In the case of macular edema, laser treatment may result in obliteration of the leaking vascular structures and/or in reflex vasoconstriction with decreased fluid delivery to the treated area. In the case of choroidal neovascularization, laser treatment may induce thrombosis of the abnormal vessels and/or may induce treated RPE cells to elaborate inhibitors of neovascularization (a mechanism that also may operate in the treatment of retinal neovascularization). The most commonly used lasers include the 1) Nd:YAG, which is used in the disruption of "after-cataract" (YAG capsulotomy), peripheral iridectomy, lysis of fibrotic tissue (in the anterior or posterior segment), lysis of vitreoretinal adhesions (in selected cases); 2) argon blue-green, which is restricted to treatment outside the foveal avascular zone (FAZ); 3) argon green, used inside or outside the FAZ; 4) krypton red, which allows better penetration through lens opacities, mild vitreous hemorrhage, and thin subretinal blood than argon; 5) and organic dye laser, which has various wavelengths, including yellow, orange, and red. Dye yellow is useful when coagulating a blood-containing lesion that contains little pigment especially if the media is hazy. It may be useful in treating microaneurysms and macroaneurysms, retinal neovascularization (direct vessel closure), and telangiectatic retinal vessels (for example, in Coats' retinopathy). Orange may be useful for treating choroidal new vessels (CNVs), angiomatosis retinae, choroidal hemangioma, advanced retinal telangiectasia, and direct retinal vascular closure (for example, feeder vessel closure). Red may be useful for treating CNVs (due to choroidal and RPE melanin content), panretinal photocoagulation with minimal vitreous hemorrhage or with intraretinal hemorrhage, as well as structural retinal defects (for example, tears, lattice degeneration). Some side effects of laser surgery include decreased central vision, decreased peripheral and/or night vision, and scotomata (blind spots) in the treated area.
|
 |
 |
| residency program /// patient care services /// research |
| ophthalmic medical assistant program /// continuing medical education |
| facilities /// faculty /// library |