Considerations for the Use of Photobiomodulation in the Treatment of Retinal Diseases.

Photobiomodulation (PBM) refers to the beneficial effect produced from low-energy light irradiation on target cells or tissues. Increasing evidence in the literature suggests that PBM plays a positive role in the treatment of retinal diseases. However, there is great variation in the light sources and illumination parameters used in different studies, resulting in significantly different conclusions regarding PBM's therapeutic effects. In addition, the mechanism by which PBM improves retinal function has not been fully elucidated. In this study, we conducted a narrative review of the published literature on PBM for treating retinal diseases and summarized the key illumination parameters used in PBM. Furthermore, we explored the potential molecular mechanisms of PBM at the retinal cellular level with the goal of providing evidence for the improved utilization of PBM in the treatment of retinal diseases.

[Comparative hemodynamic characteristics of patients with the organ of vision subjected to low-intensity laser radiation of the green and red wavelengths].

This comparative study was designed to evaluate effect of low-intensity speckle laser radiation in the green and red wavelengths on intraocular hemodynamics in 202 patients (202 eyes) with retinal vascular problems and without them. Irradiation was performed using "Izumrud" and "Rubin" adapters for an AMO-ATOS unit. Peak systolic velocity and peripheral resistance index in posterior short ciliary arteries and central retinal artery were measured. It was shown for the first time that green speckle laser radiation (wavelength 535 nm) has more pronounced (compared with the red light) effect on intraocular hemodynamics; thereby, it makes a greater contribution to the improvement of the visual function (e.g. in the case of glaucoma) and to the widening of the fields of vision.

Photostimulation of mitochondria as a treatment for retinal neurodegeneration.

Absorption of photon energy by neuronal mitochondria leads to numerous downstream neuroprotective effects. Red and near infrared (NIR) light are associated with significantly less safety concerns than light of shorter wavelengths and they are therefore, the optimal choice for irradiating the retina. Potent neuroprotective effects have been demonstrated in various models of retinal damage, by red/NIR light, with limited data from human studies showing its ability to improve visual function. Improved neuronal mitochondrial function, increased blood flow to neural tissue, upregulation of cell survival mediators and restoration of normal microglial function have all been proposed as potential underlying mechanisms of red/NIR light.

Presumed intraocular lymphoma in a 60-year-old man with AIDS.

A 60-year-old man with AIDS and active pulmonary tuberculosis presented with a rapidly growing chorioretinal tumor. Tuberculostatics had no effect on the tumor but radiation resulted in a quick decrease in its size. It is therefore believed to be a lymphoma. No biopsy was performed. An intraocular lymphoma in a patient with AIDS has not yet been described.

Tuberous sclerosis in infancy.

PURPOSE: To report two infants with tuberous sclerosis who initially were considered to have retinoblastoma. PATIENTS AND METHODS: An 8-day-old infant was referred with small tumors in the posterior poles of both eyes. A left microphthalmos with ciliochoroidal coloboma was present. Computed tomographic (CT) scanning of the brain showed scattered high-density subependymal foci in the lateral ventricle thought to be consistent with calcification resulting from intrauterine viral infection. Argon laser photocoagulation was applied to lesions in the right eye. Because one tumor was situated on the retina straddling the coloboma in the left eye, external beam radiotherapy was administered. A 5-month-old girl presented with a large mass in a left microphthalmic eye. Calcification was present on B-scan ultrasonography and CT scanning. Vitreous seeding was noted to originate from the tumor. The contralateral eye manifested four small gray translucent retinal tumors in the posterior pole. CT scan and magnetic resonance imaging (MRI) revealed multiple periventricular subependymal lesions, including one at the foramen of Monro. RESULTS: Repeated examinations in the younger child under anesthesia revealed small new retinal lesions that appeared to enlarge gradually. She developed intractable seizures and her electroencephalogram revealed a modified hypsarrhythmia recording. A careful review of available CT scans and MRI displays suggested the diagnosis of tuberous sclerosis. The child's most recent examination under anesthesia revealed multiple newly developed hamartomas. In the older child, prompt diagnosis was made on the basis of the intracranial radiologic findings. CONCLUSION: Retinal hamartoma presentation may vary in infancy. Small, initially fleck-like gliotic lesions appear to enlarge gradually and eventually may form gray, translucent tumors. Large astrocytic hamartomas of the retina associated with tuberous sclerosis may resemble retinoblastoma, particularly if the mass is large, calcified, and associated with vitreous seeding. Although ophthalmic presentation was reminiscent of retinoblastoma in both patients, radiologic evidence of subependymal hamartomas pathognomic for tuberous sclerosis helped establish the correct diagnosis. We stress the importance of intracranial radiologic findings in this regard.

[Leopard spot chorioretinopathy. Initial manifestation of recurrent acute lymphocytic leukemia]. / Leopardenfleck-Chorioretinopathie. Erstes Anzeichen eines Rezidivs einer akuten lymphozytischen Leukämie.

An 11-year-old girl with a history of acute lymphocytic leukemia of the central nervous system had attained complete remission for almost 3 1/2 years after combination chemotherapy and radiotherapy when she developed iritis and chorioretinopathy of the right eye. Neither an anterior chamber tap nor a diagnostic vitrectomy revealed leukemic cells. Both nonspecific anti-inflammatory therapy and antiviral treatment were unsuccessful. Finally, lymphoblasts were detected in the cerebrospinal fluid and in the bone marrow after repeated lumbar puncture and bone marrow aspiration. Combination chemotherapy alone was resumed, resulting in the resolution of all acute ocular symptoms and bone marrow involvement. Only the leopard-spot-like pigmentary fundus changes persisted. The child has now remained in continuous complete remission for 1 1/2 years.

[Clinical course and treatment of angiomatosis of the retina]. / Przebieg i leczenie naczyniakowatosci siatkówki.

Basing on 11 cases of angiomatosis retinae, diagnosed and treated in the last 30 years in the Ophthalmological Clinic in Halle, the authors discussed the problems concerning this rare disease. Their observations confirmed the opinion that photocoagulation is the method of choice in the treatment of angiomatosis retinae and that it is successful in small, less than 2 disc diameter angiomas. The further possible therapeutical methods are cryocoagulation, radioactive-isotopes and vitrectomy. As the treatment should be repeated and the long-lasting follow-up is necessary, the efficient cooperation with the patients is very important.

[Intravasal laser irradiation of autologous blood in the treatment of eye diseases]. / Intravazal'noe lazernoe obluchenie autokrovi v lechenii nekotorykh glaznykh zabolevanii.

Treatment of central nonexudative chorioretinal dystrophies, vascular opticopathies, keratitis and uveitis associated with disorders of immunity status is a pressing problem of ophthalmology. Intravascular laser exposure of the blood was used for the treatment of these conditions. ALOK-1 device for low-energy He-Ne intravenous irradiation of the blood was used. The authors analyze the results attained in 15 patients (24 eyes) with central nonexudative chorioretinal dystrophies and vascular opticopathies (group 1) and in 16 ones (20 eyes) with chronic relapsing keratitis and uveitis (group 2). A positive effect was attained in all the cases, manifesting in group 1 in improvement of vision acuity, widening of visual field, normalization of electrophysiological parameters and in group 2 in improvement of vision acuity, rapid resorption of corneal precipitate, reduced injection of the eyeball and opacities in the vitreous body, a more rapid corneal epithelialization, and normalization of blood and lacrimal immunograms. The attained effect may be explained by a complex neurotrophic and immunomodulating effect of laser. The method is sufficiently effective and simple, this permitting its use on an outpatient basis.

[Normal tissue tolerance to external beam radiation therapy: eye structures]. / Dose de tolérance à l'irradiation des tissus sains: l'oeil.

The radiation dose received by the eye depends on the pathology, tumour location (ocular globe, orbit, neighboring structures) and the radiation technique. The major complication is the complete loss of vision, which is often multifactorial. This article, based on a literature review, describes the radiation effects and the tolerance doses for all eye structures: cornea, lens, retina, optic nerves, orbit and ocular adnexa.

Environmental damage to the retina and preconditioning: contrasting effects of light and hyperoxic stress.

PURPOSE: Environmental stress (bright light, hypoxia) can "condition" retinal photoreceptors, increasing their resistance to subsequent stress. The present study tests whether another photoreceptor-lethal stress, hyperoxia, can induce similar resistance. METHODS: Vulnerability to hyperoxia was tested in young adult C57BL/6J mice exposed to 1000 lux cyclic light for 1 week or to 50% O2 for 1 week and then to 75% O2 for 2 weeks. Vulnerability to light was tested in Balb/cJ mice exposed to 300 lux cyclic light for 2 days or to 75% O2 for 2 weeks and then to 1000 lux cyclic light for 1 week. Retinas were analyzed for photoreceptor death, levels of stress-related proteins (GFAP, FGF-2, MnSOD, acrolein), and the regulation of candidate neuroprotective genes (HSP70.1, Ledgf, FGF-13, Timp2). RESULTS: Light preconditioning did not cause measurable death of photoreceptors but reduced photoreceptor death induced by subsequent hyperoxic or light stress, reduced levels of stress-related proteins, and maintained the length and organization of photoreceptor outer segments. Hyperoxic preconditioning caused measurable cell death but provided no protection against subsequent hyperoxic or light stress. Of the four candidate neuroprotective proteins examined, the regulation of only one (Timp2) seemed associated with the neuroprotection observed. CONCLUSIONS: Light preconditioning, causing only minimal damage to photoreceptors, induced protection against subsequent stress from both hyperoxia and light. By contrast, hyperoxic preconditioning caused measurable photoreceptor damage but induced no protection against light or hyperoxia. These data suggest a separation between stress-induced damage to photoreceptors and the upregulation of protective mechanisms, encouraging the search for ways to protect the retina without damaging it.

Radiation therapy in proliferative vitreoretinopathy. A prospective randomized study.

In a prospective study of the effect of postoperative radiation therapy for the prevention of reproliferation of membranes and recurrent proliferative vitreoretinopathy (PVR) two similar groups of patients with retinal detachment and PVR grade D1 to D3 in one eye were compared. Half the eyes (30) received a total dose of 3000 cGy after surgery; the other half remained untreated. After a follow-up of 6 months and 14 months or more (maximum 36 months) the anatomical and functional results of each group were compared. After 6 months in the unirradiated group 57% (17/30) remained attached and 43% (13/30) had detached again. In the irradiated group 63% (19/30) were attached and 37% (11/30) had detached. However, there was no statistically significant difference between the two groups (P = 0.479, Fisher's Exact Test). After 14 months the number of cured and uncured eyes remained the same in the unirradiated group, while in four of the eyes in the irradiated group a later onset of reproliferation and detachment occurred (after 7, 8, 12 and 14 months, respectively). A final cure rate of 57% (17/30) was achieved in the unirradiated group and a 50% (15/30) cure rate in the irradiated group. Thus the failure rate was 43% (13/30) in the unirradiated group and 50% (15/30) in the irradiated group (P = 0.473, Fisher's Exact Test). No side effects from the radiation were observed in any case and no radiation retinopathy occurred during an observation period of up to 3 years.(ABSTRACT TRUNCATED AT 250 WORDS)

[Capillary hemangioma of the retina. Laser scanning tomography follow-up after radiotherapy]. / Kapilläres Hämangiom der Netzhaut. Laser-Scanning-tomographische Verlaufsbeobachtungen nach Strahlentherapie.

We present a patient with isolated angiomatosis retinae, in whom ruthenium irradiation was administered for treatment of a secondary serous retinal detachment. Prior to therapy, we measured an increased vessel diameter. Following treatment, decreasing venous vessel diameter was documented three-dimensionally utilizing laser scanning tomography. The changes in vessel height (87%) exceeded the changes in width (49%). This is most probably because the vessels are embedded in the nerve fiber layer, stabilized by the surrounding tissues more in a horizontal than in a vertical direction. In addition, spontaneous venous pulsation located in the optic disc and in the retina was documented.

Irradiation pretreatment before fibroblast implantation in experimental PVR.

Fibroblast injection into the vitreous body causes traction detachment in the rabbit's eye. Various working groups reported different results on the main causes of the development of experimental PVR. These contradictions encouraged us to investigate the main source of experimental PVR by irradiating the ocular tissues before fibroblast implantation thus suppressing cell proliferation originating from host tissue. Over a period of 3 weeks, 22 eyes received ten radiations in a total dosage of 3000 rad. After the last radiation, 250,000 fibroblasts were implanted into 22 eyes. In another 4 eyes, fibroblast implantation but no radiation was carried out. After 8 weeks, 59% of 22 eyes developed different stages of retinal detachment. Comparison with the group of unirradiated eyes, which developed retinal detachment in 85%, revealed no significant differences in the number of detachments.

A study on the compliance of the patients with ocular fundus diseases.

PURPOSE: To investigate the compliance of the patients with ocular fundus diseases with recommendation for follow-up examination after laser treatment, and the underlying reasons for non-compliance. METHODS: 53 patients with ocular fundus disease were asked to fill in a questionnaire which includes the socio-demographic characteristics, fear of the fundus disease, conception of the laser treatment and the motivation for staying healthy. Variables were compared for the compliers group and the non-compliers group by chi-square test. RESULT: Of the 53 subjects, 35 were classified as non-compliers and 18 were classified as compliers. There was no statistically significant difference between the two groups on all selected socio-demographic factors, conception of the laser treatment and the motivation for staying healthy. Significant difference was found between the two groups on two of those items concerning the fear of the diseases (P < 0.05). About half of the participants showed the lack of knowledge about the laser treatment. CONCLUSION: The present study revealed the poor compliance of the patients with fundus disease. Patient's health beliefs influenced their compliance status.

Hemodynamic changes after ruthenium irradiation of Hippel's angiomatosis.

The authors report a case of Hippel's angiomatosis successfully treated with contact beta irradiation. The area of the multiplex retinal angioma and the accompanying retinal detachment was irradiated with a 106Ru/106Rh radioactive applicator. Hemodynamic changes due to irradiation were followed up in the ipsilateral ophthalmic artery with transcranial Doppler sonography. Scarring was also demonstrated by fluorescein angiography and A- and B-scan ultrasonography. Irradiation caused the narrowing and later the occlusion of the precapillaries and capillaries (i.e. the resistance vessels) and that of the shunts inside the angioma; consequently, vascular resistance increased. Transcranial Doppler sonographic recordings showed a decrease in blood flow velocity as compared to pathologically increased blood flow velocity in angiomas, and a gradual increase in vascular resistance which was lower before treatment.

Evaluation of radiation therapy for experimental proliferative vitreoretinopathy in rabbits.

We evaluated effects of radiation therapy on experimental proliferative vitreoretinopathy (PVR) induced in rabbits by double gas compression of the vitreous followed by homologous dermal-skin fibroblast injection. Electrons were irradiated in two rabbit groups. Group A animals (20 eyes) received 1000 cGy of irradiation immediately after cell injection; group B rabbits (9 eyes), which showed pucker formation 7 days after cell injection, were irradiated on that day at the same dose as was given to group A rabbit. Control animals (14 eyes) were not irradiated. The incidences of traction retinal detachment on day 28 were: control, 86%; group A, 10%; and group B, 22%. There were statistically significant differences between control and group A values and between control and group B values. No significant difference was found between group A and group B. Irradiation of 1000 cGy did not alter the histological picture of experimental PVR. The results showed that radiation suppressed the development of PVR when applied not only immediately after cell injection but also during pucker stages.