title: Comparison of retinal lesions produced by transscleral krypton laser photocoagulation, transpupillar krypton laser photocoagulation and cryocoagulation.
abstract: We compared the retinal lesions produced by transscleral and transpupillar krypton lasers and cryocoagulation. Transscleral laser photocoagulation was applied under indirect ophthalmoscope visual control with indentation of the sclera by the laser probe. Transpupillar laser was performed with a Volk 90D lens. The power and the spot size were adjusted to create lesions of similar size and intensity as in transscleral photocoagulation. The output power needed for transscleral photocoagulation was 0.2W with exposure time of 3-5 sec. In the transpupillar photocoagulation the output power was 0.3W and the exposure time 2-3 sec, respectively. The lesions were studied histologically 1h, 1, 3, 7, 30 and 60 days after treatment. Histopathological studies of the krypton laser lesions revealed destruction and scarring of the outer layers of the retina and the choroid. The lesions produced by transpupillar and transscleral laser appeared to be rather similar. These results indicate that, in the rabbit eye, there is no difference between the lesions produced by the transpupillar or transscleral route of laser application. Transscleral laser application may have clinical advantages over transpupillary laser in the eyes with hazy media or in other cases when transpupillar laser is not possible.
authors.affiliation: Department of Ophthalmology, Helsinki University Hospital, Finland.
authors.forename: V P
authors.initials: VP
authors.lastname: Suomalainen
mesh_terms: D000818:Animals; D001284:Atrophy; D015862:Choroid Diseases / Q000209:etiology / Q000473:pathology; D003452:Cryosurgery / Q000009:adverse effects*; D004487:Edema; D005355:Fibrosis; D017075:Laser Coagulation / Q000009:adverse effects*; D009887:Ophthalmoscopy; D011817:Rabbits; D012164:Retinal Diseases / Q000209:etiology* / Q000473:pathology; D000267:Tissue Adhesions