Laser coagulation

The so-called laser photocoagulation or ( in the eyes of Medical Jargon " LK" ) is an effective treatment method in certain diseases of the retina. As a routine procedure, this has long been established. Their beginnings she found in 1949 in the Sonnenlichtkoagulation by Gerhard Meyer- Schwickerath and its further development by xenon photocoagulation was used in the still with a "normal ", but high-intensity flashes of light. One uses it today in clinical practice usually the green / blue-green argon laser, krypton or dye lasers are also to be found. The in ophthalmology also used frequency-doubled neodymium -YAG laser comes to the retina is usually not used.

Expiration

The laser coagulation of the retina is an outpatient procedure usually. After placing a contact lens on the locally anesthetized cornea, the practitioner first examines using a low-energy beam on the target therapeutic area. The therapeutic laser pulse is triggered separately by the clinician and is long in retinal applications between 50 and 300 ms.

Physical Basics

The absorption of the laser beams in the retinal pigment epithelium and choroid ( choroidal ) through the biological filter light melanin leads to a heat development in this area. This results in thermal necrosis ( cell death ) by denaturation of the affected area, which show up as dark pigmented scars only as a white fluffy flock and over time. The Netzhautlaserkoagulation is thus always a retina -destroying treatment method, but this is quite intentional and the destroyed retinal areas are so small or so arranged in the rule that they are not perceived by the patient.

Areas of application

Retinal holes and degenerations

Retinal holes can be caused by the Glaskörperzug or even with myopia. If there is only one hole and no significant retinal detachment, one can by LK the hole edges with the underground " weld " and thus prevent the formation of a retinal detachment. For safety's sake also hole precursors ( diluted retina in the peripheral retina, known as degenerative areas ) are surrounded by LK and so hedged.

Diabetic macular edema

By fine Koagulationsherde close to the center of the retina ( paracentral LK) is stimulated, the pumping activity of the retinal pigment epithelium. This allows you to reach a swelling diabetic macular edema and usually prevent further vision loss. It uses laser herd size of approximately 100 microns. Coagulation can only districts with lots of edema - conditional vascular changes take place limited (focal paracentral LK) or coagulating with diffuse macular edema the entire macula, with the exception of the fovea with a laser point grid (so-called Grid -LK ).

In the ischemic maculopathy coagulation does not make sense, since the residual vessels that are still intact, can be destroyed and the disease would progress so. However, if large ischemic zones exist, an LK this ( foveafernen ) Districts may be useful to prevent proliferative retinopathy.

Severe non- proliferative and proliferative diabetic retinopathy

The syndromes of severe non- proliferative and proliferative diabetic retinopathy, it is important that this occurring with blood off underserved districts by retinal laser photocoagulation. Therefore, working with larger (about 500 microns in diameter) and more herds. In addition, the entire retina except the macula coagulated ( panretinal LK). The individual herd should be a non- overlapping set with about a herd size distance to avoid visual field defects. In the severe non- proliferative retinopathy over a large area coagulation with initially about 1000 herds is to be made. Shows no improvement or even an evolution in the ophthalmoscopic picture or in angiography, it must be supplemented with up to 4000 or more in individual cases herds. The other eye should be also investigated on the need for treatment about it. Per session no more than 700-800 stoves should be lasered in order to avoid side effects such as a serous retinal detachment or intraocular pressure changes and deterioration of night vision.

Must be lasered paracentral and panretinal in a patient with macular edema and proliferation, it should always install the paracentral LK carried out because there may be a worsening of macular edema with a significant loss of visual acuity by only panretinal LK.

In some patients with proliferative diabetic massive Retnopathie is by extensive LK in the longer -term course, the risk of retinal detachment ( tractional retinal detachment ) by cicatricial contraction of proliferations. The scarring of the proliferation is quite desired by the practitioner, the shrinkage and the associated problems do not. Nevertheless, there is usually no other alternative, where appropriate, the scarred proliferation membranes must be surgically removed by a vitrectomy in patients.

Wet age -related macular degeneration

Macular degeneration is a disease of the central retina when there is a vessel growth beneath the retina. With the LK you can burn off those vessels specifically, but here the retina will be damaged, what Visual loss or seeing black spots ( scotomas ) may result. The immediate center of the retina fovea may be coagulated by no means with the argon laser, as this will cause an irrecoverable and massive loss of visual acuity. For the treatment of vascular neoplasms under this retina district, there are other therapies ( photodynamic therapy, injection therapies such as Avastin).

Retinopathy of prematurity

Also in the retinopathy of prematurity can prevent progression of the disease to the complete detachment of the retina timely laser photocoagulation of peripheral retinal areas.

Alternatives

Since the laser photocoagulation is done by light, lens, cornea and vitreous should be clear in mind and must not be tarnished. Turbidity can for example be caused by a cataract ( cataract ) or by dense vitreous hemorrhage.

In such a case the so-called cryotherapy is applied in an approximately -70 ° C cold probe is held to the eye under local anesthesia. Conjunctiva and cornea not be damaged, the retina, however, is exactly as in the desolate laser photocoagulation ( cold -induced cell necrosis ) and forms scar at the desired locations. The results are almost the same as for the laser coagulation, but the method is more complex and not so well as to dose the LK. When rubeotischen secondary glaucoma and very peripheral retinal holes, this method is often used.

• Therapeutic procedures in ophthalmology
• Laser application