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At least 1,099 records · Page 61Linked to original sources
PubMed2005

[Transpupillary thermotherapy for circumscribed choroidal hemangioma].

OBJECTIVE: To evaluate the efficacy of transpupillary thermotherapy (TTT) on circumscribed choroidal hemangioma. METHODS: Ten eyes of 10 cases with circumscribed choroidal hemangioma (age 16-48, average 34.4) were included in the present study. Six cases had previous green laser (4 argon and 2 krypton) photocoagulation, TTT as a primary treatment was used for other 4 cases without previous laser application. Fluorescein angiography, visual acuity, anterior segment and fundus examination, perimetry test, FFA/ICGA and ultrasonography were performed in all patients before the treatment. One to five infra red diode laser spots (810 nm with power of 800-1200 mW, diameter of 3 mm) were delivered on the surface of tumor with 60 seconds exposure, additional 10-20 seconds exposure was used in some cases. Second treatment was given 1-3 month later if there was active leakage demonstrated by fluorescein angiography. The followed-up period was 6-36 months (averaged 14.5 month). RESULTS: After transpupillary thermotherapy, 9 eyes (90%) showed partial regression of the tumor. Average visual acuity was 0.25 and 0.6 before and after TTT, respectively. Six patients showed improvement of vision acuity, but vision acuity in 4 patients with cystic macular degeneration remained unchanged. No recurrences were observed within follow-up averaged 14.5 months. Transpupillary thermotherapy did not associate with any significant complications. CONCLUSION: Transpupillary thermotherapy is effective to treat circumscribed hemangioma of choroid either as a primary treatment or supplementary therapy to previous laser photocoagulation.

Adolescent↗
PubMed1990

[A role of the retinal pigment epithelium in the involution of subretinal neovascularization].

We clarified a role of the retinal pigment epithelium (RPE) in the regression of experimentally induced subretinal neovascularization (SRN) in monkey. Eight eyes of 5 rhesus monkeys were used in this study. Two weeks after intense krypton laser photocoagulation to the posterior pole of the fundus, 0.5M l-ornithine hydrochloride solution 0.03 ml was injected intravitreously for the purpose of selective RPE damage. After ornithine injection, SRN continued without any evidence of spontaneous regression over 8 weeks following photocoagulation. Histopathologically, SRN developed with wide lumen in the subretinal space accompanied with serous detachment of the sensory retina, and new vessels were not enveloped completely by the proliferating RPE cells. We already showed that experimentally induced subretinal neovascularizations naturally regress spontaneously by envelopment of RPE cells 5 to 8 weeks after photocoagulation. Our results suggested that SRN persist actively without regression due to incomplete enclosure by RPE by selective damage of RPE at the active stage of SRN. We have confirmed that the RPE cells played an important role at the involution stage of SRN.

Animals↗
PubMed1991

[Choroidal neovascularization, experimental and clinical study].

As a special lecture at the 95th annual Congress of the Japanese Ophthalmological Society in 1991, we presented experimental studies on choroidal neovascularization (ChNV), and clinical studies on senile disciform macular degeneration (exudative age-related macular degeneration). We produced experimentally ChNV on monkey eyes using intense photocoagulation with krypton laser. We showed the retinal pigment epithelium (RPE) played a heavy role as inducer or inhibitor for ChNV at different stages of development or involution of experimental ChNV. Senile disciform macular degeneration is becoming a leading cause of blindness in the elderly in Japan. We examined 473 eyes in 398 cases of this disease during the past 5 years. Nineteen percent were bilaterally affected, males were affected 3 times prevalent than in female, and average age was 67 in years. Predisposing signs were degeneration or atrophy of RPE, hard or soft drusen, and serous detachment of RPE in the macula. In early stage, serous retinal detachment stage appeared and showed good outcome by laser treatment. Subretinal hematoma form showed next better outcome in acute onset and acute course. Advanced form of disciform lesion showed worse outcome. A form (subretinal cystic form) associated with large serous RPE detachment showed the worst outcome and scarcely indicated for laser treatment. We describe clinical features of each form and stages of the disease and clinical course. Early detection, early correct diagnosis and early laser treatment must be essential for prevention of blindness due to this disease.

Adult↗
PubMed1992

In situ measurements of lens fluorescence and its interference with visual function.

Irradiation of the primate lens by near-ultraviolet wavelengths results in a blue fluorescence, which can be an intraocular source of veiling glare. This study quantitated the fluorescence intensity as a function of exciting intensity and wavelength. As the exciting wavelength was increased from 360 to 430 nm, the decreasing fluorescence intensity (for equal radiant exposures) was partially offset by a shift in the fluorescence spectrum to wavelengths of greater luminous efficiency so the luminance of the lens fluorescence remained approximately constant. The measured luminance of the lens fluorescence was high enough to imply degradation of visual function as a result of reduced contrast of the retinal image. To obtain an objective measure of visual deficit associated with the fluorescent glare, the visual evoked potential (VEP) elicited by counterphased sine-wave gratings was recorded while the subject eye was continuously exposed to the 413 nm emission from a krypton laser. The VEP amplitude was reduced in the presence of the exciting laser even at levels defined as "safe" (ie, where exposure levels are insufficient to induce an acute ocular lesion). Because the direct glare effect of the exciting radiation was negligible in this experiment, the VEP response loss is attributed to the effect of the lens fluorescent glare.

Animals↗
PubMed1991

[Spatial fluorescence imaging of atherosclerotic plaque: contrast enhancement by 2 wavelength laser stimulation, digital image processing and dye marking].

A new video-enhanced fluorescence imaging technique has been used for the first time for in vitro differentiation of human atherosclerotic plaques vs normal arterial wall. Laser-induced superficial tissue fluorescence of specimens from human aorta was documented after alternating excitation with violet (405 nm +/- 5 nm) and blue (470 nm +/- 10 nm) krypton-ion laser light. Subsequent digital subtraction of the corresponding fluorescence images allowed to differentiate areas of atherosclerosis from normal intima. Fluorescence intensity was correlated with the morphological aspect of samples and histology of the plaque. Dihematoporphyrin-ether/ester (DHE) incubation enhanced fluorescence contrast of plaques in comparison to normal artery vessel wall. Depending on the concentration of the incubation solution (10, 20, and 40 micrograms DHE/ml NaCl solution), fluorescence increased. Fluorescence intensity was highest in fatty plaque areas, while calcific lesions showed no substantial DHE uptake.

Angioplasty, Laser↗
PubMedDate not supplied

Consequences of the nuclear power plant accident at Chernobyl.

The Chernobyl Nuclear Power Plant accident, in the Ukrainian Soviet Socialist Republic (SSR), on April 26, 1986, was the first major nuclear power plant accident that resulted in a large-scale fire and subsequent explosions, immediate and delayed deaths of plant operators and emergency service workers, and the radioactive contamination of a significant land area. The release of radioactive material, over a 10-day period, resulted in millions of Soviets, and other Europeans, being exposed to measurable levels of radioactive fallout. Because of the effects of wind and rain, the radioactive nuclide fallout distribution patterns are not well defined, though they appear to be focused in three contiguous Soviet Republics: the Ukrainian SSR, the Byelorussian SSR, and the Russian Soviet Federated Socialist Republic. Further, because of the many radioactive nuclides (krypton, xenon, cesium, iodine, strontium, plutonium) released by the prolonged fires at Chernobyl, the long-term medical, psychological, social, and economic effects will require careful and prolonged study. Specifically, studies on the medical (leukemia, cancers, thyroid disease) and psychological (reactive depressions, post-traumatic stress disorders, family disorganization) consequences of continued low dose radiation exposure in the affected villages and towns need to be conducted so that a coherent, comprehensive, community-oriented plan may evolve that will not cause those already affected any additional harm and confusion.

Accidents↗
PubMed1991

[Effects on the retina and choroid of transpupillary diode laser photocoagulation].

A transpupillary retinal photocoagulator utilizing GaAlAs diode laser which emits an 810 nm beam has been constructed. It has a continuous-wave mode with a maximum output of 400 mW at the cornea. Animal experiments with monkeys were carried out successfully at various intensities to produce controlled coagulations. Observation by ophthalmoscopy, light and electron microscopes at different time intervals proved diode laser photocoagulation produced more intensive effects in choroid than krypton red laser (647 nm). However, due to the greater absorption of the choroid, there is a tendency to over-coagulation unless conditions are carefully set. No serious side effects in the retina and choroid were observed during the experiments.

Animals↗
PubMed1990

Laser treatment of age-related maculopathy (AMD) with subretinal neovascularization (SRN).

Age-related macular degeneration (AMD) is the main cause of visual loss in the Western world. In 80-90% it is the result of the exudative type of AMD with subretinal neovascularization (SRN). As soon as SRN is suspected, fluorescein angiography must be performed without delay. When the neovascular membrane is well-defined, sparing the subfoveolar area--a situation observed in only a small portion of the patients--then green argon or red krypton laser treatment is indicated, the only therapy currently available. The 3-year success rate is about 50% owing to the recurrence of SRN, an as yet unsolved problem. The prognosis also depends on the intensity of the lesions of non-exudative macular degeneration. Statistical evaluation shows that in most patients the main effect of photocoagulation is only to postpone the loss of central vision.

Aged↗
PubMed1990

Parasympathetic denervation of the ciliary muscle following retinal photocoagulation.

Cynomolgus monkeys underwent unilateral PRP with xenon arc or argon or krypton laser light, employing burn intensity, size, spacing, and topography analogous to standard clinical (eg, Diabetic Retinopathy Study) treatment. Shortly thereafter, accommodative responsiveness to topical eserine and electrical stimulation of the EWN was diminished, accommodative responsiveness to systemic pilocarpine was enhanced, and the number of muscarinic receptors in the ciliary muscle was reduced in the PRP-treated eyes compared to the contralateral controls. In most instances, these parameters returned to normal over 6 to 12 weeks and the abnormalities could be induced again by another round of PRP. However, in some PRP-treated eyes, accommodative responsiveness to EWN stimulation and topical eserine remained subnormal permanently (greater than 1 year). Light and electron microscopy of the ciliary muscle and choroid confirmed the early interruption and degeneration and the subsequent regeneration of the intraocular parasympathetic nerves following PRP. These findings are similar to those seen after surgical removal of the ciliary ganglion and posterior ciliary nerves, and indicate that PRP produces an intraocular parasympathetic denervation of the ciliary muscle. This phenomenon may explain the loss of voluntary accommodation which can follow PRP in prepresbyopic humans. Three cynomolgus monkeys underwent nasal and temporal HRMP in one eye with the argon laser. One to four weeks later, accommodative responses to IM pilocarpine, topical eserine, and electric stimulation of the EWN did not differ markedly in the treated and control eyes. Five weeks after HRMP, posterior PRP was performed in the same eye, sparing the previously treated areas. One to four weeks later, accommodative responses in the PRP-treated eyes were clearly subsensitive to central electrical stimulation, but supersensitive to IM pilocarpine, compared to the contralateral controls. These findings indicate that extensive parasympathetic denervation of the ciliary muscle occurs following PRP but not following HRMP. Consequently, we infer that parasympathetic motor nerve fibers to the ciliary muscle do not travel preferentially with the LPCN, but rather travel primarily if not exclusively with the more numerous SPCN. If the monkey and the human are comparable, sparing the horizontal retinal meridians during clinical PRP so as not to disturb the LPCN will probably not help to preserve ciliary muscle function and accommodation.

Accommodation, Ocular↗
PubMed1990

[Scanning laser ophthalmoscopy. Its value in macular diseases].

The scanning laser ophthalmoscope provided a high quality television image of the fundus with minimal illumination of the retina. This new device based on a totally new electro-optical principle allowed a detailed exploration of macular function directly under simultaneous fundus control. The focused beam of a yellow krypton laser (568,2 nm) was swept up and down, rights and links across the fundus to form a raster of parallel lines on the retina. The S.L.O. illuminated only a single retinal point at a time and illumination was reduced to less than 70 microw/cm2 versus 100,000 microns/cm2 for indirect ophthalmoscopy and 4,000,000 microw/cm2 for fluorescein angiography. The intensity of the laser beam could be modified with the microcomputer by means of an acousto-optic modulator. It was possible to produce static or dynamic graphic designs that were simultaneously viewed by the patient and observed by the examiner on the patient's fundus on the video monitor. Further computerized analysis of the videotaped scanning laser ophthalmoscopic images gave a functional retinal map with correction for shifts of stimulus position due to fixational saccadic eye movements. The map showed true retinal location of 1. fixation area; 2. scotoma. The clinical evaluation was completed with 3. measurement of visual acuity in any foveal or parafoveal location. The results of scanning laser ophthalmoscopy were illustrated with the report of datas in a patient with diffuse retinal pigment epithelial decompensation.

Adult↗
PubMed1990

[Treatment of macular holes by vitrectomy and gas].

Five cases of retinal detachment with macular hole show the effectiveness of the treatment: Vitrectomy + exchange Fluid-gas. Red krypton laser applied around macular hole is not necessary. Treatment vitrectomy-exchange Fluid gas must be performed rather than Aspiration-gas in a first attempt.

Aged↗
PubMed1990

[The role of retinal pigment epithelium in the early stage of development of subretinal neovascularization].

In order to evaluate the role of retinal pigment epithelium (RPE) in the early stage of experimental subretinal neovascularization, we severely damaged RPE cells before the development of subretinal neovascularization. Three adult rhesus monkeys were used in this study. One mol/l l-ornithine hydrochloride saline solution was injected intravitreously at 2 weeks before intense krypton laser photocoagulation on the retina at the posterior pole, and clinical and histopathological course were studied at 1 to 28 days after photocoagulation. As a result, no evidence of new vessel formation could be observed clinically throughout the entire course. Histopathologically, at 3 days after photocoagulation, slight proliferation of RPE cells was identified by electron microscopy at the margin of the laser lesions, and budding of vascular endothelial cells derived from choroidal microvessels was observed in the choroid. However, no newly-formed vessels extended into the subretinal space at 7 days or more after photocoagulation. These results confirmed our hypothesis that proliferated RPE cells had inductive effect on the growth of endothelial cells in the early stage of development of subretinal neovascularization.

Animals↗
PubMed1985

Recurrent subretinal neovascularization.

A retrospective analysis of a consecutive series of patients treated with krypton red laser (KRL) photocoagulation for subretinal neovascularization (SRN) secondary to drusen-related macular degeneration (DMD) was carried out to investigate the frequency and nature of recurrent neovascularization (recurrence). A classification of various types of recurrences based on the clinical and fluorescein angiographic features and the onset of their appearance in the postoperative course was used in this study. Patient, fundus, and membrane variables were examined in search of relevant high risk factors predisposing to recurrences. The membrane's proximity to the fovea and its relative lack of pigmentation were individual factors which were associated with a high risk of recurrence (P less than 0.05 for distance and P = 0.005 for color). Multivariate analysis also indicated that a greater distance from the fovea (P less than 0.05) and a darker color (P = 0.002) were favorable features to the primary membrane, reducing the probability of a recurrence. Overall, 39% of the patients experienced recurrences (23% of the patients had treatable recurrences and 16% had non-treatable recurrences extending under the center of the fovea). The membranes recurred predominantly at the margin of the photocoagulation burn. The recurrences were also noted relatively early in the postoperative course, 65% within two months after photocoagulation of the primary membrane. The fluorescein angiographic and clinical nature of these membranes and the visual effect of retreatment are also discussed in the paper.

Aged↗
PubMed1986

Exudative age-related maculopathy.

While this patient was asymptomatic, patients need to be aware of visual changes which may be secondary to choroidal neovascular membranes. Amsler grid monitoring during the interval between examinations may assist in early detection. Detailed fundus examinations and patient education are also needed. While the efficacy of krypton treatment remains to be proven, timely diagnosis and appropriate referral, when a treatable lesion is present, will improve the prognosis for maintaining macular function in exudative ARM.

Age Factors↗
PubMed1987

Subretinal neovascular membranes associated with choroidal nonperfusion and retinal ischemia.

This is the first well-documented case of co-existent underlying choroidal nonperfusion in an eye with a subretinal neovascular membrane that was subsequently treated with krypton red laser photocoagulation by the senior author (LEM). The possible role of chronic macular ischemia secondary to choroidal circulatory impairment is discussed in relationship to other well-established risk factors. Perhaps treatment to improve macular oxygenation would be a reasonable alternative to eradication of the neovascularization by direct laser photocoagulation.

Aged↗
PubMed1989

Choroidal neovascularization in an eye with a macular hole.

We report the case of a 68-year-old woman who initially presented with an idiopathic macular hole OD and atrophic macular degenerative changes and who subsequently developed subretinal neovascularization OU. The subretinal neovascularization evolved through the macular hole OD and decreased visual acuity to counts fingers, but the membrane was successfully treated OS with krypton laser photocoagulation and stabilization of visual acuity at 20/50 over the eight-year postoperative follow-up. This is the first report, to our knowledge, of a membrane developing through a macular hole. This may be a more common occurrence than reported due to obscuring of details from hemorrhage and exudate as part of the disciform process.

Aged↗
PubMed1989

Increase in pulmonary blood flow during cold stimulation of the mouth in patients with systemic lupus erythematosus.

To determine whether pulmonary blood flow is altered by cold stimulation of the mouth, a cold stimulus was induced by having 11 systemic lupus erythematosus patients without pulmonary fibrosis hold ice in their mouths. Lung perfusion was measured by continuous venous infusion of Krypton-81m. During the period in which the ice was held in the mouth, 2 patients showed 32% and 41% increase in pulmonary blood flow. After the cold stimulus was removed, pulmonary blood flow recovered in these patients to within the control range by a margin commensurate with the increase in the duration of the cold stimulus, suggesting that the response may be due to an abnormal reflex of the autonomic nervous system.

Adult↗
PubMed1989

Retinal laser photocoagulation. Effect of rate of energy delivery.

Three monkeys were treated with krypton red laser photocoagulation in a manner simulating treatment of a choroidal neovascular membrane. One eye of each monkey was treated by employing immediately the power level needed to produce a lesion judged biomicroscopically to be of sufficient intensity (Method A). The fellow eye was treated by starting with lower power levels and then gradually increasing to the level needed to produce a similar-appearing lesion (Method B). Parameters of spot size and treatment duration were kept constant. Animals were sacrificed three days, eight days, and four months after treatment. Both methods of treatments spared the overlying ganglion cell layer in all fundus locations, but Method A induced cell loss in the inner nuclear layer while Method B spared it. Since reaching the clinical endpoint for Method B required fewer spots at the highest power level, the number of spots at the highest power level is probably the most important factor in determining degree of inner retinal absorption. Since both methods of treatment resulted in satisfactory closure in the choriocapillaries, the histopathologic differences may not be clinically important.

Animals↗