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PubMed1993

Safety considerations for simultaneous multiple wavelength exposure in scanning laser ophthalmoscopes.

A method has been developed for calculating the maximum permissible exposure for multiple wavelength lasers used in scanning laser ophthalmoscope systems. The method is based on the assumption that when the human eye is simultaneously exposed to multiple wavelength laser light, the thermal and photochemical effects on the retina are additive and independent of each other. A linear addition method is used to calculate multiple laser maximum permissible exposures for scanning laser ophthalmoscope systems. This paper also includes a discussion of possible synergistic effects of retinal biological effects caused by multiple laser exposure. An example is given to illustrate a conservative, theoretical approach to estimating the maximum permissible exposure for simultaneous multiple wavelength laser exposure.

Humans↗
PubMed1983

Use of an ophthalmoscope for objective refraction of noncooperative patients.

Refractive ophthalmoscopy was performed on 16 subjects aged 5 to 27 years. Subjective refractions were performed on both eyes of the subjects followed by an ophthalmoscopic determination performed under cycloplegia by the authors. A 0.94 correlation was found between the subjectively determined "dry" refractive error and the refractive error determined ophthalmoscopically under cycloplegia by both examiners. The results of the two procedures differed by 1 D or less 82% of the time. The results indicate that refractive ophthalmoscopy is an alternative method for objectively determining refractive error in non-cooperative patients with poor fixational stability.

Adolescent↗
PubMed1983

Spectral irradiances of and maximal permissible exposures to two indirect ophthalmoscopes.

Recent reports in the literature have indicated that exposure to certain high intensity sources used in clinical procedures may be damaging to the retina. To investigate this problem, the spectral irradiance of two indirect ophthalmoscopes [American Optical (AO) and Keeler] was measured. The instruments do show operational differences, the most striking of which was the difference in the total irradiance produced at the maximum voltage setting, the Keeler instrument providing nearly 3.6 times greater irradiance than the AO indirect ophthalmoscope. The sources are evaluated as blue light hazards, and maximal permissible exposures (MPE) are calculated and compared to the MPE established by ANSI Z-136 guidelines.

Humans↗
PubMed1996

Scanning laser ophthalmoscope macular perimetry in the evaluation of submacular surgery.

PURPOSE: Submacular surgery for choroidal neovascularization (CNV) is under investigation in the treatment of age-related macular degeneration (AMD) and the presumed ocular histoplasmosis syndrome. Four case studies are presented to demonstrate scanning laser ophthalmoscope (SLO) testing in the pre- and postsurgical evaluation of visual function in patients with subfoveal CNV secondary to AMD, presumed ocular histoplasmosis syndrome, and submacular hemorrhage secondary to AMD. METHODS: Patients underwent a visual assessment pre- and 6 months postoperatively, consisting of low vision visual acuity measurement, SLO macular perimetry of dense and relative scotomas, and analysis of the preferred retinal locus for fixation (PRL) location and ability. RESULTS: Visual acuity, dense and relative scotoma size and location, and PRL location were compared; and relationships between anatomic and functional changes were observed. Decreases in scotoma size and improvement in PRL location and ability usually corresponded with improved visual acuity. Preoperative scotoma and PRL location guided retinotomy site selection. CONCLUSION: Scanning laser ophthalmoscope macular perimetry and PRL testing may be useful adjuncts in the visual assessment of submacular surgery and may advance under-standing of the effects of submacular surgery on visual function. In addition, this testing may be used to plan location of surgical interventions for macular diseases.

Adult↗
PubMed2005

Characteristics of visual field defects by scanning laser ophthalmoscope microperimetry after radial optic neurotomy for central retinal vein occlusion.

PURPOSE: To evaluate visual field defects after radial optic neurotomy (RON) for the treatment of central retinal vein occlusion (CRVO) by using scanning laser ophthalmoscope microperimetry. METHODS: Thirteen eyes of 13 patients with severe vision loss (< or = 20/200) from CRVO who underwent pars plana vitrectomy and RON had postoperative Goldmann kinetic perimetry, scanning laser ophthalmoscope microperimetry, and fluorescein angiographic evaluation. RESULTS: After a mean follow-up of 8 months, 6 of the 13 patients had visual improvement by > or = 2 lines. Eight patients developed an anastomosis at the radial cut. Postoperatively, sectorial visual field loss arising from the optic head was found by Goldmann perimetry in six patients, and a thin nerve fiber bundle defect was found in three patients. Four patients had no detectable visual field defect shown by Goldmann perimetry, but microperimetry demonstrated an absolute nerve fiber bundle defect arising from the radial cut at the optic disk for three of these patients. CONCLUSION: Visual field loss after RON for the treatment of CRVO is a frequent complication. The etiology of this visual loss appears to be a combination of mechanical trauma to the nerve fiber layers and ischemia of the optic disk circulation.

Adult↗
PubMed1984

Use of a new generation ophthalmoscope.

A new optical configuration for an ophthalmoscope is a hybrid of the present direct and indirect instruments, combining the strengths of both to increase overall efficiency. Cross polarization is used as a means of reducing glare and increasing clarity of detail. A fiberoptic light source increases light intensity, but reduces heat, weight, and inconvenience. These characteristics result in a self-contained, handheld indirect instrument. This ophthalmoscope is mechanically aligned and therefore easy to use. Both ophthalmologist and nonophthalmologist may find this instrument of benefit in ocular examinations.

Eye Burns↗
PubMed1992

Ownership of direct ophthalmoscopes by medical students.

In September 1986 the Department of Education and Science withdrew the equipment grant for clinical medical students. This coincided with a reduction of 50% in the level of ownership of direct ophthalmoscopes amongst a group of 51 medical students who commenced their medical studies after September 1986 (no longer eligible for the equipment grant), when compared with a group of 63 students (in the same clinical year) who started the medical course before 1 September 1986 and who were hence still able to claim the equipment grant. The majority of non-owners gave lack of finance as the reason for non-ownership. Owners of ophthalmoscopes performed ophthalmoscopy more frequently than non-owners, but the difference did not reach statistical significance.

Education, Medical, Undergraduate↗
PubMed1982

TV indirect ophthalmoscope.

A prototype of TV indirect ophthalmoscope (black-and-white type) was developed to enhance education in ophthalmology. Its weight is 450 g, and pictures obtained were fairly satisfactory. The authors have used this ophthalmoscope not only for practicing indirect iphthalmoscopy by students, but also as monitoring device during retinal surgery.

Humans↗
PubMed2001

Differentiation between primary and secondary Raynaud's phenomenon: a prospective study comparing nailfold capillaroscopy using an ophthalmoscope or stereomicroscope.

BACKGROUND: Nailfold capillary microscopy is a routine procedure in the investigation of patients with Raynaud's phenomenon (RP). As a standard method, nailfold capillary morphology is inspected with a stereomicroscope to look for capillary abnormalities such as giant loops, avascular areas, and bushy capillaries, which have all been found to be associated with certain connective tissue diseases. AIM: To investigate prospectively whether nailfold capillary inspection using an ophthalmoscope is of equivalent diagnostic value to standard nailfold capillary microscopy. METHOD: All the fingers of 26 patients with RP were examined in a blinded fashion and compared with the final diagnosis one month later. RESULTS: All giant loops, large avascular areas, and bushy capillaries were identified by both methods. The correlation for moderate avascular areas and crossed capillaries was 0.93 and 0.955 respectively. The correlation for minor abnormalities that do not contribute to the differentiation between primary and secondary RP was 0.837 and 0.861 respectively. All patients were classified identically by the two methods. CONCLUSION: For the evaluation of patients with RP, nailfold capillary morphology can reliably be assessed with an ophthalmoscope.

Female↗
PubMedDate not supplied

Scanning laser ophthalmoscope-evoked multifocal-ERG (SLO-m-ERG) by using short m-sequences.

PURPOSE: To demonstrate the possibility of topographic mapping of retinal function under simultaneous control of fixation in humans, by scanning laser ophthalmoscope evoked multifocal electroretinography (SLO-m-ERG). METHODS: A confocal scanning laser ophthalmoscope was used as a stimulator and trigger unit to take m-ERGs. Short m-sequences based on a modified algorithm were used, with the advantage that each measurement cycle can be evaluated separately. We examined 78 normal subjects; in 62 a distortion factor of 1:1 was applied, and a factor of 1:4 in 16. RESULTS: The recorded amplitudes decreased with eccentricity, approximately following the decrease of retinal cone density. Amplitudes were higher in the central hexagonal element in the group with 1:4 distortion than in the group with the 1:1 distortion setting. CONCLUSIONS: SLO-m-ERG is a reliable technique for topographic mapping of retinal function under simultaneous control of fixation.

Adult↗
PubMed2003

Compact scanning laser ophthalmoscope with high-speed retinal tracker.

The effectiveness of image stabilization with a retinal tracker in a multifunction, compact scanning laser ophthalmoscope (TSLO) was demonstrated in initial human subject tests. The retinal tracking system uses a co confocal reflectometer with a closed-loop optical servo system to lock onto features in the fundus. The system is multifarious and modular to allow configuration for many research a clinical applications. Adult volunteers were tested without mydriasis to optimize the tracking instrumentation and to characterize imaging performance. The retinal tracking system achieves a bandwidth of greater than 1 kHz, which permits tracking at rates that greatly exceed the maximum rate of motion of the human eye. The TSLO system stabilized images to an accuracy of 0.05 deg in all test subjects during ordinary saccades with a velocity up to approximately 500 deg/s. Feature lock was maintained for minutes despite subject eye blinking. Even when nearly 1000 frames were coadded, image blur was minimal. Successful frame coaddition allowed image acquisition with decreased noise in low-light applications. The retinal tracking system significantly enhances the imaging capabilities of the scanning laser ophthalmoscope.

Equipment Design↗
PubMed2005

Optical slicing of human retinal tissue in vivo with the adaptive optics scanning laser ophthalmoscope.

We present imaging results in human retinal tissue in vivo that allowed us to determine the axial resolution of the adaptive optics scanning laser ophthalmoscope (AOSLO). The instrument is briefly described, and the imaging results from human subjects are compared with (a) the estimated axial resolution values for a diffraction-limited, double-pass instrument and (b) the measured one for a calibrated diffuse retinal model. The comparison showed that the measured axial resolution, as obtained from optical sectioning of human retinas in vivo, can be as low as 71 microm for a 50 microm confocal pinhole after focusing a 3.5 mm beam with a 100 mm focal-length lens. The axial resolution values typically fall between the predictions from numerical models for diffuse and specular reflectors. This suggests that the reflection from the retinal blood vessel combines diffuse and specular components. This conclusion is supported by the almost universal interpretation that the image of a cylindrical blood vessel exhibits a bright reflection along its apex that is considered specular. The enhanced axial resolution achieved through use of adaptive optics leads to an improvement in the volume resolution of almost 2 orders of magnitude when compared with a conventional scanning laser ophthalmoscope and almost a factor of 3 better than commercially available optical coherence tomographic instruments.

Adult↗
PubMed1998

Scanning laser ophthalmoscope microperimetry.

In this article, the methodologies and clinical applications of microperimetry performed by scanning laser ophthalmoscope (SLO) are described. This technique provides functional results by direct visualization of the macular area. We present the most interesting data about clinical applications in ocular pathology. SLO microperimetry is a new diagnostic tool in ophthalmic practice. It permits an exact, point-to-point correspondence between fundus image and perimetric results, impossible to achieve by projection perimetry, so representing the most suitable device for simultaneous fundus imaging and psychophysical testing. Microperimetry is performed by SLO (Rodenstock),1 which permits other applications. SLO microperimetry allows the real-time functional study of retinal sensitivity by direct ophthalmoscopic control of the retinal surface. Foveal or excentric fixation can be assessed as well. Instability of fixation during computerized perimetry is a possible misleading factor resulting in unexplainable findings, especially in eyes with decreased visual acuity. The main characteristic of microperimetry is the ability to see the stimuli presented on the retina in real time: this permits an accurate monitoring of fixation and correlation of anatomical or pathological features directly with retinal function.

Humans↗
PubMedDate not supplied

[Topographic mapping of retinal function with a scanning laser ophthalmoscope and multifocal electroretinography using short M-sequences].

A new method of multifocal electroretinography making use of scanning laser ophthalmoscope with a wavelength of 630 nm (SLO-m-ERG), evoking short spatial visual stimuli on the retina, is proposed. Algorithm of presenting the visual stimuli and analysis of distribution of local electroretinograms on the surface of the retina is based on short m-sequences. Mathematical cross correlation analysis shows a three-dimensional distribution of bioelectrical activity of the retina in the central visual field. In normal subjects the cone bioelectrical activity is the maximum in the macular area (corresponding to the density of cone distribution) and absent in the blind spot. The method detects the slightest pathological changes in the retina under control of the site of stimulation and ophthalmoscopic picture of the fundus oculi. The site of the pathological process correlates with the topography of changes in bioelectrical activity of the examined retinal area in diseases of the macular area and pigmented retinitis detectable by ophthalmoscopy.

Adult↗
PubMed1978

A small pupil binocular indirect ophthalmoscope.

A description of a lightweight small pupil binocular indirect ophthalmoscope is presented. This instrument can be used with well dilated pupils and clear media as any stereoscopic indirect ophthalmoscope. However, the instrument can be simply and easily adjusted for usage in patients with small pupils or opacities of the media. The optical and mechanical principles employed are presented. The technique of utilization for small pupil viewing is outlined.

Dilatation↗
PubMed1977

Visually evoked response testing with a stimulator-ophthalmoscope. Macular scars, hereditary macular degenerations, and retinitis pigmentosa.

Visually evoked responses (VERs) were recorded from 47 patients under age 60 years with macular scars, hereditary macular degenerations, or retinitis pigmentosa. A hand-held, two-channel stimulator-ophthalmoscope was used to present to the central fovea a 1.5 degrees flickering stimulus centrally superimposed on a steady 10 degrees background. All 31 patients with visual acuity (VA) 20/50 or less had abnormal VERs; among patients with VA 20/25 to 20/40, all six with macular degenerations and five of ten with retinitis pigmentosa also showed abnormal VERs. Abnormal VERs were either out of phase or indistinguishable from noise. Sensitivity of the technique depended on a low ratio of stimulus to background retinal illuminance and the fact that the stimulus could be visualized by the examiner through the ophthalmoscope and maintained on the central fovea througout testing.

Adolescent↗
PubMed1986

Ophthalmoscopic and histologic findings in cytomegalovirus retinitis treated with BW-B759U.

Recent reports have suggested a role for BW-B759U in the treatment of cytomegalovirus retinitis. The present study presents the ophthalmoscopic features in three treated patients, and examines the microscopic findings in the eyes of the first patient ever treated with BW-B759U for cytomegalovirus retinitis. Ophthalmoscopic findings of improvement on drug therapy included remission of perivascular infiltration, stabilization of the extent of the retinal area involved, and development of a pigmented chorioretinal scar in the involved area. Relapses occurred with cessation of therapy, and repeated courses of therapy were required. One patient developed a rhegmatogenous detachment with retinal breaks in an atrophic area of treated retinitis. Electron microscopic examination of the eyes of one patient disclosed the persistence of cytomegalovirus inclusions in retinal cells despite previous drug therapy. These findings suggest a virostatic action for BW-B759U.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Localized suprachoroidal hematomas. Ophthalmoscopic features, fluorescein angiography, and clinical course.

We describe the ophthalmoscopic characteristics, fluorescein angiographic features, and clinical course of four patients with a localized suprachoroidal hematoma. Each of the four patients developed a darkly pigmented fundus lesion a short time following uncomplicated intraocular surgery. In every case, the lesion appeared ophthalmoscopically similar to a choroidal malignant melanoma. However, fluorescein angiography showed neither choroidal fluorescence blockage nor the double-circulation pattern characteristic of choroidal melanomas. Instead, each lesion exhibited a central fluorescein pattern similar to that of the surrounding uninvolved choroid, relative marginal hypofluorescence, and overlying choroidal folds. Ultrasonography revealed acoustic hollowness of each lesion without choroidal excavation. The lesions disappeared completely within 1 to 2 months, leaving no visible trace. We discuss the differential diagnosis of these lesions and stress the diagnostic value of fluorescein angiography.

Aged↗