Effects of circadian rhythm disruption on retinal physiopathology: Considerations from a consensus of experts.

The circadian rhythms originate within the organism and synchronize with cyclic fluctuations in the external environment. It has been demonstrated that part of the human genome is under control of the circadian clock and that a synchronizer that helps to maintain daily rhythms is Melatonin, a neuro-hormone primarily synthesized by the pineal gland during the night. The chronic disruption of circadian rhythm has been linked to many conditions such as obesity, metabolic syndrome, type 2 diabetes, cancer, and neurodegenerative diseases. Studies in the mice showed that the disruption of the retinal circadian rhythm increases the decline during the aging of photoreceptors, accelerating age-related disruption of cone cell structure, function, and viability and that the melatonin receptor deletion seems to influence the health of retinal cells, speeding up their aging. In conclusion, preserving the circadian rhythms could be to add to the prevention and treatment of age-related degenerative retinal diseases, and although additional studies are needed, melatonin could be a valid support to favor this "chronoprotection action".

The nature and frequency of neovascular age-related macular degeneration.

PURPOSE: This study was designed to evaluate the frequency and nature of neovascularization in age-related macular degeneration (ARMD) utilizing the combination of digital imaging techniques, fluorescein angiography (FA), indocyanine green (ICG) angiography, and optical coherence tomography (OCT). METHODS: A complete clinical examination was performed on 100 eyes of 93 consecutive newly diagnosed patients with neovascular ARMD. Digital fluorescein angiography, ICG angiography, and OCT were also used in evaluating those patients. Comparison of the imaging techniques to determine their value in studying the nature of the lesions. RESULTS: On the basis of existing fluorescein standards, 15 eyes were diagnosed with classic choroidal neovascularization (CNV), 15 with minimally classic CNV, and 70 with occult CNV. ICG angiography was superior for detecting the active vascular component in polypoidal CNV (16 eyes) and retinal angiomatous proliferation (14 eyes). OCT was more sensitive than FA for determining the presence of cystoid macular edema evident in the vast majority of eyes with retinal angiomatous proliferation (RAP). CONCLUSIONS: These results suggest that FA, ICG angiography, and OCT, when used in combination, will assist clinicians in best determining the precise nature of the neovascular process in ARMD.

Transpupillary thermotherapy of juxtafoveal recurrent choroidal neovascularization.

PURPOSE: To evaluate the effectiveness of low power transpupillary thermotherapy (TTT) in treating juxtafoveal recurrent choroidal neovascularization (CNV) after laser photocoagulation in patients with age-related macular degeneration (ARMD). METHODS: Eight eyes of eight patients with ARMD and juxtafoveal recurrent CNV were treated with low power TTT, delivered using an 810-nm diode laser with 350 mW, 2.0 mm spot, and 1-minute duration. Visual acuity (VA) ranged from 20/100 to 20/50. Treatment effect was evaluated by fluorescein angiography, indocyanine green angiography, and VA measurements (Early Treatment Diabetic Retinopathy Study) at 1-week, 2-week, and monthly follow-up visits. RESULTS: No retinal damage was visible ophthalmoscopically during treatment. At the first follow-up visit, seven eyes had obliteration of CNV and one eye required a second TTT application. VA was unchanged in six eyes, improved in one eye, and worsened in one eye. Recurrences occurred in all eyes between 1 and 7 months after TTT and were treated with photodynamic therapy (PDT). More than two PDT treatments were performed in each eye in the year after recurrence. CONCLUSIONS: Low power TTT is as able to close juxtafoveal recurrent CNV as is high power conventional laser photocoagulation but does not prevent recurrences. Further intervention with TTT in order to treat recurrences is under investigation.