Ophthalmoscopes

On the basis of this work and other research, in 1849 Helmholtz was appointed professor of physiology at the University of Koonigsberg. There he devoted himself to the physiology of the eye, first explaining the mechanism of lens accommodation. In 1851 Ins invention of the ophthalmoscope, still the basic instrument used by eye doctors to peer at the retina of the eye, immediately made Helmholtz famous. In 1852 he also became the first experimentalist to measure the speed of nerve impulses in the human body. 

Inspection of the retina during an ophthalmoscopic examination is greatly facilitated by mydriasis, or the dilation of the pupil. Parasympathetic stimulation of the circular muscle layer in the iris causes contraction and a decrease in the diameter of the pupil. Administration of a muscarinic receptor antagonist such as atropine or scopolamine prevents this smooth muscle contraction. As a result, sympathetic stimulation of the radial muscle layer is unopposed, causing an increase in the diameter of the pupil. These agents are given in the form of eye drops that act locally and limit the possibility of systemic side effects. 

OPHTHALMOSCOPE 25 VOLT COMPACT W/HALOGEN LIGHTS POLARIZED FILTER 6540014587337 EA 133.50 ... 

The duration of repeat-dose studies should be at least as long as the proposed clinical study. These studies are designed to establish a dose-response relationship, define target organ(s) of toxicity, and determine whether observed toxicities are reversible. Evaluation parameters should include not only those routinely performed in the acute studies, but those performed in the additional studies as well. Special tests, such as ophthalmoscopic, electrocardiograph, body temperature, and blood... 

Retrobulbar hemorrhages During the administration of botulinum toxin type A for the treatment of strabismus, retrobulbar hemorrhages sufficient to compromise retinal circulation have occurred from needle penetrations into the orbit. It is recommended that appropriate instruments to decompress the orbit be accessible. Ocular (globe) penetrations by needles have also occurred. An ophthalmoscope to diagnose this condition should be available. Inducing paralysis in 1 or more extraocular P.788... 

Ophthalmoscopic examination Topical One drop of phenylephrine HCl 2.5% is placed in each eye. 

Relief of dry and inflamed nasal membranes Intranasal Use as needed Diagnostic aid in ophthalmoscopic exam, treatment of corneal edema Ophthalmic solution Apply 1-2 drops q3-4h. Ophthalmic ointment Apply once a day or as directed. 

Hermann (Ludwig Ferdinand) von Helmholtz, 1821-1894. Professor of physiology at Bonn and at Heidelberg. Professor of physics at Berlin. Invent or of the ophthalmoscope, an instrument for examining the retina of the eye. He expressed the principle of the conservation of energy in mathematical form... 

Ocular Effects. Ptosis was observed in Sprague-Dawley rats exposed to 2,330 mg/m3 for 4 hours in an inhalation chamber (Holbert 1989). No evidence of treatment-related ophthalmoscopic lesions was observed in hybrid rats (10 of each sex) exposed to up to 11.6 mg/m3 diazinon (nose-only) for 3 weeks,... 

Thomson WE. 1903. Note on a case of vesication of the cornea by potassium bichromate. Ophthalmoscope 1 214-216. 

Failure to use drugs when clinically indicated, particularly mydriatic agents for diagnosis, is a significant source of liability claims. A hypothetical example illustrates how the standard of care can be applied if drugs are not used appropriately for diagnostic purposes. If a patient has received a blow to the eye from a fist, ball, or other blunt object, the optometrist must rule out the possibility of a retinal break. To perform a reasonable examination, one that conforms to the expected standard of care, dilation of the pupil is necessary. In feet, it may be argued that examination of the retinal periphery with a binocular indirect ophthalmoscope is required under these circumstances. Therefore feilure to dilate the pupil and view the retinal periphery fells below the standard of care. If for some reason the optometrist cannot perform a dilated examination, the patient must be referred to another clinician so that the appropriate evaluation can be performed. 

Similarly, subjects with light irides recovered accommodative function more rapidly. Overall, Paremyd provided adequate dilation for the intense illumination of the binocular indirect ophthalmoscope in all study subjects, irrespective of iris pigmentation. Subjects also reported that Paremyd was more comfortable on initial instillation than the 0.5% tropicamide and 2.5% phenylephrine combination. Paremyd is currently only available throngh compounding pharmacies. 

Intracranial hypertension (pseudotumor cerebri) secondary to the use of many tetracycline analogues can occur in infents and adults. When the antibiotic is discontinued, cerebral fluid pressure and any accompanying visual and ophthalmoscopic changes usually return to normal over days or weeks. Rarely, tetracycline causes blood dyscrasias such as hemolytic anemia, thrombocytopenia, neutropenia, and eosinophilia. 

Topical application of glycerin in concentrations from 50% to 100% results in a significant reduction of corneal edema within 1 to 2 minutes. Because application to the eye is painful, a topical anesthetic must be instilled before use. It is useful in ophthalmoscopic and gonioscopic examination of the eye in acute angle-closure glaucoma, bullous keratopathy, and Fuchs endothelial dystrophy. 

ICG s primary use is as a fluorescent dye for retinal and choroidal angiography. Its low fluorescence property initially limited its use in angiography smdies. Improvements in video technology, the introduction of appropriate excitation and barrier filters, and the development of the scanning laser ophthalmoscope with a modification to permit infrared recording ultimately allowed choroidal angiograms with high temporal and spatial resolution. 

Scheider A, Kaboth A, Neuhauser L. Detection of subretinal neovascular membranes with indocyanine green and an infrared scanning ophthalmoscope. Am J Ophthalmol 1992 113 45-51. 

Characteristics of the vision loss can aid in the diagnosis of demyelinating optic neuropathy. The vision loss is progressive, is maximal in 1 week, and achieves variable recovery within 4 to 6 weeks. The reduction in vision frequently is accompanied or preceded by periocular pain on movement of the eye. Color vision often is severely impaired, and visual fields most commonly reveal a relative central scotoma. The ophthalmoscopic picture is usually one of a normal optic nerve head, because most commonly the optic neuropathy is behind the globe and thus is called retrobulbar optic neuritis. When there is optic disc swelling, it is known as papillitis. 

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