Excimer laser photorefractive keratectomy for hyperopia.

PURPOSE: To achieve less variation in the refractive outcome of hyperopic photorefractive keratectomy (PRK) by enlarging the treatment zone to 9.0 mm. SETTING: Marienhospital, Amberg, Germany, and Klinika Ocni A Esteticke Chirurgie, Zlin, Czech Republic. METHODS: This prospective clinical study was based on the results of PRK in 68 hyperopic eyes (62 patients) using an MEL 60 excimer laser. Mean attempted correction was +4.85 diopters (D) +/- 1.45 (SD) (range +2.00 to +8.25 D). Maximum follow-up was 12 months (68 eyes). RESULTS: One year after PRK, 55 eyes (81%) were within 1.00 D and 40 eyes (59%) were within 0.50 D of the intended correction (predictability). Best corrected visual acuity was unchanged or improved in 62 eyes (92%) (safety). Four eyes (6%) lost one line, 1 eye (1%), two lines, and 1 eye (1%), three lines. Sixty-six eyes (97%) had an uncorrected visual acuity of 20/40 or better (efficacy) and 27 (40%), 20/20 or better. CONCLUSION: Photorefractive keratectomy with a 9.0 mm treatment zone was an efficient and relatively safe procedure for correcting hyperopia of up to 8.25 D. The predictability was good. Great care must be taken to improve the centration of the optical zone.

[A laser coagulation technic in central retinal vein occlusion]. / Technika laserové koagulace u okluze centrální sítnicové vény.

The authors analyze the method of laser therapy in venous retinal occlusions. In view of the different therapeutic approach in occlusion of the branch and the trunk of the retinal vein, the paper has two parts. In occlusion of the branch of the retinal vein the authors describe the applied techniques of laser photocoagulation recommended by L'Esperance--quadrant barrage, barrier of the macula and arteriolar constriction. Technical data on photocoagulation are presented. In the treatment of occlusions of the trunk of the retinal vein the authors use panretinal photocoagulation, however, only in the ischaemic form of occlusion as a prevention of neovascular glaucoma. The authors mention some of their own experience with the treatment of venous occlusions of the retina by argon laser photocoagulation and they present their own therapeutic schedule.

[Visual evoked potentials in diabetics]. / Zrakové evokované potenciály u diabetiku.

The authors investigated visually evoked potentials in 27 patients with diabetes mellitus type I and II. In 77.8% of the patients abnormal values of visually evoked responses were found. The authors did not find a significant relationship between the degree of diabetic retinopathy and the disorder of visually evoked potentials.

The histologic and electronmicroscopic study of melanoblastoma after argon-laser therapy.

The left eye was enucleated for secondary detachment in a 50-year-old patient, with choroid melanoblastoma treated with argon-laser photocoagulation six months before. Histological examination of the enucleated eyeball showed pigmented melanoblastoma with some focal fibrosis in the area of the previous laser treatment. There were no signs of an actual tumour cell damage on electron microscopy. The fibrosis found at the side of laser treatment was very likely to result from the local therapeutical tumour destruction which, however, was not sufficient to influence substantially its further growth.

Diabetic maculopathy and cataract extraction.

In 20 diabetic patients with diabetic retinopathy, we followed up the development of diabetic maculopathy after extraction. In 65% of the cases, the arisal or progression of the present macular edema was recorded 2 months after extraction together with a visual impairment. In 4 of them, the visual acuity adjusted itself within 10 months. The cause of this phenomenon may be traction of the vitreous body on the retina or the change in the hemodynamic conditions in the retina after cataract extraction. Since an improvement in the visual acuity occurs only in 30% of the involved eyes, it is recommended to apply the photocoagulation treatment on arisal or deepening of the edema.

Diabetic maculopathy and glaucoma.

Our group of 200 with laser treated diabetics included 5 patients (2.5%) with bilaterally treated primary simple glaucoma. All of them had diabetic maculopathy exclusively within the range of simple diabetic retinopathy. The focal type of maculopathy occurred 5 times, the cystoid 3 times, the ischemic once. There was emphasized the necessity to devote increased care to diabetics with glaucoma because for them glaucoma represents a risk factor regarding the further development of the visual function and the extent of the visual field. On the other hand, the decreased foveolar sensitivity in some diabetics with glaucoma may reduce the visual acuity which thus becomes an unreliable criterion of the success of the laser therapy.

Smokers and diabetic maculopathy.

Of 200 examined diabetic patients with diabetic maculopathy there were 27 smokers, 23 of them diabetics of type II. In comparison with the control group of 23 diabetics with diabetic maculopathy-nonsmokers, the smokers showed a significantly higher incidence of the ischemic type of diabetic maculopathy which, however, did not manifest itself more markedly in their visual acuity.

Treatment of perimacular proliferations in diabetic ophthalmopathy with fluorouracil.

Five eyes from 4 diabetic patients with proliferations perimacularly were treated with fluorouracil after previous unsuccessful treatment with laser therapy. Fluorouracil was administered in two series of five injections each, every second day in daily doses of 10 to 15 mg subconjunctivally. Fluorouracil was well tolerated. It has a certain inhibitory effect (both on vessels and particularly on the formation of the accompanying fibers) on proliferations reaching the macula at a distance from the vessels out of reach of the visual disc, it has no suppressing effect on papilloretinal proliferations.

Mild diabetic rubeosis and panretinal photocoagulation.

In a group of 32 treated and 20 untreated eyes of diabetics with proliferative retinopathy, we applied fluorescein angiography (FAC) of the iris for a period of 5 to 7 weeks to follow up the effect of panretinal photocoagulation (PRP) on mild diabetic rubeosis, which was considered to be a neovascularization of the iris on FAG smaller than 0.5 mm2 in the early phases of the angiogram. The evaluation was carried out by two independent examiners. In the treated group, an improvement occurred in 3 of 32 eyes, in the control group in 2 of 20 eyes. We did not find regression of mild rubeosis after PRP.