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At least 127 records · Page 7Linked to original sources
PubMed1995

Static fundus perimetry using the scanning laser ophthalmoscope with an automated threshold strategy.

PURPOSE: The purpose of this study was to develop software that allows the performance of routine static threshold perimetry using the scanning laser ophthalmoscope (SLO) and the comparison of the results with conventional computerized cupola perimetry. The original software does not allow performance of static threshold perimetry within a reasonable examination time. METHODS: Static perimetry was performed in random order on 50 healthy eyes using our SLO staircase threshold perimetry technique and the Octopus 500 (program 38). We compared the relative sensitivities for each of 25 corresponding visual field locations. RESULTS: Mean sensitivity in the SLO perimetry amounted to 32.7 dB (range 25-37 dB) while it was 28.7 dB in the Octopus. For all test locations the SLO showed higher dB values on average. The mean difference between both methods was 3.7 +/- 0.8 dB (range 1.4-5.8 dB) when the test locations at the blind spot were excluded (linear regression between the two methods: r = 0.843, P < 0.0001). The mean time interval between two stimulus presentations was 2.5 s with the SLO perimetry. CONCLUSION: With the Heidelberg software, automated static threshold perimetry using the SLO is possible within reasonably short examination times. The mean time interval between two test point presentations is about one tenth of that necessary using the original Rodenstock software. There is a systematic difference between SLO and Octopus fields of about 4 dB which was not very much influenced by the stimulus locations.

Adult↗
PubMed1997

Scanning laser ophthalmoscope imaging of fluorescein-labelled blood cells.

PURPOSE: To demonstrate the feasibility of a technique for the visualization by scanning laser ophthalmoscope (SLO) of fluorescein-labelled autologous leukocytes and platelets in retinal vessels. METHOD: Individual blood samples from rats and rabbits were centrifuged to isolate platelets and leukocytes, then passively labelled with fluorescein and reinjected into the same animal. An SLO was used to visualize and record cell displacement in the retinal circulation. Labelled platelets were analysed by flow cytometry. RESULTS: By SLO, platelets appeared as a heterogeneous particle flow, and individual leukocytes appearing as brighter spots could easily be traced. Flow cytometry showed that after labelling platelets were well individualized and their size was slightly increased. CONCLUSION: Circulating blood cells can be visualized in retinal vessels by a simple method consisting of passive labelling of autologous platelets and leukocytes by fluorescein. No platelet toxicity was detected. This method could be applied to the study of blood cell movement in human retinal vascular diseases.

Animals↗
PubMed1993

Assessment of optic disc topography with scanning laser ophthalmoscope.

Evaluation of the topography of the optic disc is of clinical importance to assess the degree of nerve damage. We conducted a study in 17 glaucomatous and 20 control subjects with a scanning laser ophthalmoscope (SLO; Rodenstock) and compared the results with those in conventional photographs. A tomographic image of the cup area in control subjects and the neuroretinal rim area in glaucomatous subjects obtained with the SLO was smaller than that in photographs taken with a conventional camera (P < 0.05 and P < 0.01 respectively). In both the control and glaucoma groups, the optic disc area obtained with the SLO was significantly smaller than that in conventional photographs (P < 0.01). The coefficient of variation of the optic disc parameters studied with the SLO range from 4.2% to 9.1%. A correlation between the optic disc indices studied with SLO and the mean defect of the visual field was statistically significant. The tomographic images obtained by the SLO permit accurate assessment of optic nerve damage.

Fundus Oculi↗
PubMed2002

[Multifocal ERG with confocal scanning laser ophthalmoscope. Comparison with monitor simulation].

BACKGROUND: Multifocal electroretinograms (mfERG) were recorded using a confocal scanning laser ophthalmoscope (cSLO) and compared to the results from conventional monitor stimulation. METHODS: Single and repeated measurements were recorded from 23 normal subjects using the cSLO (Heidelberg Retina Angiograph, Heidelberg Engineering, Heidelberg) as well as a conventional monitor as stimulation devices. Laser power output was modified by various optical filters. The reliability of the method and agreement with the conventional monitor stimulation were determined. RESULTS: CSLO recordings showed a high degree of variability. Reduction of laser power output improved the retinal response topography and characteristically modified response variations with each filter. Differences in amplitude size between cSLO and monitor recordings decreased with increasing amplitude levels. The results of repeated measurements showed considerable variation. CONCLUSION: It is possible to use a cSLO as a stimulator for mfERG recordings. However, a relatively high degree of variability represents a significant limitation of this method. Appropriate reduction of laser power decreases variations and serves to obtain photopic response topographies.

Adult↗
PubMed2003

[Scanning laser ophthalmoscope multifocal electroretinography and microperimetry in patients with Stargardt's disease].

PURPOSE: We used a scanning laser ophthalmoscope (SLO) evoked multifocal electroretinography (mf-ERG) to evaluate retinal function in patients with Stargardt's disease. SLO microperimetry could demonstrate the size of central retinal scotoma very well in these patients. The aim of the examination was to correlate the results of SLO mf-ERG and SLO microperimetry. METHODS: In four patients with Stargardt's disease SLO mf-ERG and SLO microperimetry were performed. The area of measurement in the SLO mfERG had a 24 degrees diameter (12 degrees visual angle) at the posterior pole of the eye. Stimulation was done using a helium-neon laser (632.8 nm). Simultaneous control of fixation was made using a infrared laser (730 nm). SLO microperimetry was performed with stimuli having the size of Goldmann III stimuli and the intensities 0 dB, 12 dB and 20 dB. In this study the reduction of SLO mfERG amplitudes was correlated to graded stimulus intensities in the SLO microperimetry. RESULTS: The area of reduced retinal function in the SLO mf-ERG measurement could be well correlated to the size of the scotoma in the SLO microperimetry, using the stimulus Goldmann III with the intensity 20 dB. CONCLUSION: SLO mfERG and SLO microperimetry are sensitive methods for quantifying functional deficits and are therefore useful for performing a detailed examination of the retina.

Adult↗
PubMed1997

[Simultaneous fluorescein and indocyanine green angiography with a confocal laser ophthalmoscope].

BACKGROUND: We report on our clinical experience with a recently developed confocal scanning laser ophthalmoscope for simultaneous fluorescein and indocyanine-green (ICG) angiography. MATERIALS AND METHODS: Following injection of fluorescein and ICG mixed in one syringe simultaneous confocal scanning laser fluorescein and ICG angiography were carried out using the Heidelberg Retina Angiograph (HRA). An argon laser (488 nm) and a diode laser beam (795 nm) from an external source were delivered via single-mode fibers. Emission was recorded between 500 and 650 nm and above 810 nm, respectively. Digital images were displayed simultaneously on a monitor during angiography. RESULTS: A total of 295 simultaneous angiograms in 268 patients with various retinal and choroidal diseases, including exudative age-related macular degeneration with occult and classic choroidal neovascularization, were obtained. High-contrast images during all phases of the angiography were obtained. Besides mild side effects in similar frequency known from individual injections, no additional toxic or allergic reactions from simultaneous injections of the two dyes were observed. CONCLUSIONS: Confocal laser scanning angiography allows for simultaneous fluorescein and ICG angiography. Compared with consecutive investigations using both dyes, simultaneous angiography requires only one injection, and offers identical digital frames. Simultaneous injection is not associated with additional side effects.

Aged↗
PubMed1997

[Topography of fundus autofluorescence with a new confocal scanning laser ophthalmoscope].

BACKGROUND: We investigated fundus autofluorescence in vivo using a novel scanning laser ophthalmoscope. MATERIALS AND METHODS: A total of 550 patients with various retinal diseases were examined and compared with normal eyes. Autofluorescence was detected after excitation with an argon blue laser (488 nm), and emission was recorded with a short wavelength cut off above 500 nm. RESULTS: Reduced autofluorescence was observed in the foveal and parafoveal region due to retinal xanthophyll, along the retinal vessels, at the optic nerve head and in areas with atrophy of the retinal pigment epithelium (RPE). Autofluorescence intensity was increased either focally or diffusely in certain degenerative (AMD) or genetically determined retinal diseases (e.g., Stargardt's disease, Best's disease). CONCLUSIONS: These findings are in accordance with the view that in vivo fundus autofluorescence originates at the level of the RPE and suggest that it is derived from lipofuscin.

Adolescent↗
PubMed1998

[Imaging the tear film and in vivo cornea. Initial results with a modified confocal laser scanning ophthalmoscope].

BACKGROUND: As the slit-lamp technique is an restrictive method for the in-vivo examination and documentation of the multi-layer structure and the dynamics of the tear film and the cornea, e.g. during wound-healing processes, our aim was to find out whether it is possible to change the confocal laser scanning ophthalmoscope (CLSO; Zeiss) into a high-resolution confocal laser scanning microscope (CLSM) for the visualization of the anterior segments of the eye and the tear film by adapting a special objective system. In order to gain information concerning the function of such a cornea microscope we examined selected patients with erosion or pterygium before and after operation and subsequent phototherapeutic keratectomy (PTK), as well as some in-vitro corneal surfaces after photorefractive keratectomy (PRK). MATERIAL AND METHODS: We developed an objective adapter for the CLSO in order to focus the laser beam onto anterior segments of the eye to visualize the tear film and the layer structure of the cornea. By combining the long-distance objective or a contract objective with different zoom-optic lenses it was possible to alter the scan field size and so the magnification of the CLSM by a factor of up to 1000. RESULTS: The CLSM provides a new method for the in-vivo examination of the tear film and its dynamics as well as the thin layers of the cornea in real-time imaging technique with high contrast and resolution in non-contact or contact procedures. CONCLUSION: This system is a unique took for evaluating and monitoring the effect of excimer laser ablation after PTK and PRK on the corneal surface and the dynamics of the tear film. The application of this method causes no pain for the patient.

Cornea↗
PubMed1989

Imaging retinal densitometry with a confocal Scanning Laser Ophthalmoscope.

We describe a novel use of the Scanning Laser Ophthalmoscope (SLO), viz. as an imaging retinal densitometer. In our SLO a helium-neon or an argon laser beam is moved in a raster pattern over the retina; the reflected light is descanned (confocal SLO) and collected by a photomultiplier. Images of the fundus subtending 22 by 18 deg are displayed on a TV monitor. Single frames taken with 514 nm light were stored in a computer in arrays of 256 by 256 pixels and density differences between dark adapted and bleached images were calculated. With a full bleach density differences of about 0.35 were found in the center of the fovea; at retinal eccentricities of 15-20 deg we found 0.15. After selective bleaching with 633 nm light substantial density differences were only seen in the foveal area. We conclude that the confocal SLO is a very suitable instrument for imaging fundus reflectometry.

Densitometry↗
PubMed1996

A novel method for measuring saccade profiles using the scanning laser ophthalmoscope.

Most existing techniques for accurately measuring angular eye position vs time during a saccade (the saccade profile) need either contact to the eye or are restricted in time resolution. In this paper we introduce a new noninvasive method, with high spatial and temporal resolution, for determining saccade profiles using a scanning laser ophthalmoscope (SLO). This method uses the fact that images of a moving object taken with the SLO are not blurred (as are images from video cameras) but show a tilt with respect to images of the same stationary object. A mathematical framework is given that allows determination of a saccade profile from a restricted number of consecutive SLO video fields of the fundus during a saccade. The angular resolution obtained by this method is below 0.1 deg, and the maximum time resolution near 1 msec. Measured saccade profiles could be well approximated by a gamma function, the first derivative of which yields the saccade velocity profile. Measurements of peak saccade velocity as a function of saccade amplitudes (main sequence) using our method show good agreement with results obtained by other authors.

Humans↗
PubMed2005

Microperimetry--comparison between the micro perimeter 1 and scanning laser ophthalmoscope--fundus perimetry.

PURPOSE: To compare microperimetry using the scanning laser ophthalmoscope (SLO, Rodenstock, Germany) and the recently introduced Micro Perimeter 1 (Nidek Technologies, Italy). DESIGN: Prospective comparative observational study. METHODS: Fundus perimetry with static threshold perimetry was performed using the SLO and the MP1 in 68 eyes of 40 consecutive patients with different retinal diseases for example, central serous chorioretinopathy, macular dystrophy, and age-related macular degeneration. With both instruments, an automated 4-2-1 staircase strategy with Goldmann III stimuli and a comparable number of stimuli were applied. The depth and size of the detected scotomata as well as the location and stability of fixation were compared between both instruments. RESULTS: There was good concordance of results, with 75% (51 of 68 eyes) showing an equal defect. Whereas the MP1 showed larger defects (depth and size) in 23.5% (16/68) of eyes studied than the SLO, the defects appeared larger with the SLO in 1 eye. Concerning fixation analysis, similar results were found for fixation stability with stable fixation in 47.1% (MP1: 32/68) and 48.5% (SLO: 33/68) and likewise for the location of fixation with foveal fixation in 54.4% (37/68) with the MP1 and the SLO. Whereas the average number of stimuli was similar for both instruments (MP1 56.8 +/-16.1, SLO 62.9 +/- 17.0), examination time was prolonged with the MP1 (MP1: 11m 35s +/- 3m 47s, SLO: 10m 29s +/- 3m 23s). Throughout all examinations, fundus visualization with the SLO was superior to the MP1. CONCLUSIONS: For automated threshold microperimetry the MP1 provides results comparable to our SLO perimetry. Both instruments enable detection of sensitivity loss of the central visual field and an analysis of fixation behavior during microperimetry. Nevertheless, the MP1, with its automated real-time image alignment, facilitates examination. Additionally, the enlarged field allows testing in an area of 44 x 36 degrees instead of the 33 x 21 degree-area of the SLO. However, in comparison to our SLO-software, the current software of the MP1 requires improvements before exact measurements of defined retinal diseases are possible.

Adolescent↗
PubMed1998

Normal values for fundus perimetry with the scanning laser ophthalmoscope.

PURPOSE: To evaluate the normal light sensitivity values for fundus perimetry and their short time fluctuation (reliability) in normal volunteers of different ages. After the development of full-threshold static fundus perimetry, age-corrected sensitivity values for normal subjects are required to interpret results and to compare them with conventional computerized perimetry. METHOD: Full-threshold fundus perimetry of the central field (33 x 21 degrees) by means of the scanning laser ophthalmoscope was performed on 152 eyes of 99 healthy persons aged 16 to 77 years with normal vision and no eye disease. Fixation was simultaneously documented. Light sensitivity values were evaluated according to each subject's age and test point location. RESULTS: Linear regression analysis disclosed a significant (P < .0001) decrease of the mean sensitivity of 0.275 dB per decade of increasing age, starting with 16.6 dB at age 10 years. Standard deviation around the center of fixation was 0.287 degrees in the first decade, and it increased by 2.82 minutes of arc per decade (P < .0001). Variation in triple examinations of subjects did not differ from short time fluctuation. CONCLUSION: Visual fields examined with fundus perimetry show reliable measurements in a range comparable to conventional computerized perimetry. There is a significant correlation between increase of age and decrease of light sensitivity in fundus perimetry. Visual fields obtained with fundus perimetry seem to correlate well with known data from computerized static threshold perimetry. It should be recognized that even in normal subjects, the stability of fixation decreases with increasing age.

Adolescent↗
PubMed1999

Simultaneous indocyanine green and fluorescein angiography in retinal pigment epithelium tear using the confocal scanning laser ophthalmoscope.

PURPOSE: To describe the indocyanine green angiographic pattern of retinal pigment epithelium tears in the setting of age-related macular degeneration compared with the fluorescein angiographic features. METHODS: Twelve consecutive patients (12 eyes) with a retinal pigment epithelium tear underwent simultaneous indocyanine green angiography and fluorescein angiography with the confocal scanning laser ophthalmoscope. The findings for the two modes were compared. RESULTS: Choroidal neovascular membrane was evident beneath the rolled retinal pigment epithelium on indocyanine green angiograms in 11(92%) of 12 eyes: a focal neovascular membrane was apparent in five (42%) of 12 eyes, whereas a plaque neovascular membrane was seen in six (50%) of 12 eyes. In comparison, fluorescein angiography demonstrated late leakage as a result of occult choroidal neovascular membrane in nine (82%) of 11 eyes but no well-defined choroidal neovascular membrane. CONCLUSIONS: Indocyanine green angiography is superior to fluorescein angiography for imaging choroidal neovascularization in cases of retinal pigment epithelium tear and may serve as an important adjunct to indocyanine green-guided laser treatment in selected cases.

Aged↗
PubMedDate not supplied

Use of scanning laser ophthalmoscope microperimetry in clinically significant macular edema in type 2 diabetes mellitus.

PURPOSE: We used scanning laser ophthalmoscope (SLO) microperimetry to evaluate scotomas in patients with clinically significant diabetic macular edema (CSME) in type 2 diabetes mellitus. METHODS: We studied 19 patients (mean age = 63 years; range, 45-78 years) (19 eyes). SLO microperimetry was performed in all eyes. We divided patients into three groups as follows: dense scotoma, relative scotoma, and no scotoma. The following variables were documented: age; duration of diabetes, hemoglobin A(1c) levels; logarithm of the minimum angle of resolution (Log(MAR)) visual acuity; refractive power; a history of panretinal photocoagulation; presence or absence of proliferative diabetic retinopathy, vitreomacular separation, and cystoid changes; the type of macular edema; and stability of fixation. All variables were compared in the three groups. RESULTS: We identified 4 eyes (21.1%) with dense scotoma, 10 (52.6%) with relative scotoma, and 5 (26.3%) with no scotoma. There were significant differences in log(MAR) visual acuity among those with dense scotoma (1.4 +/- 0.5), relative scotoma (0.6 +/- 0.2), and no scotoma (0.2 +/- 0.3) (P <.05), and in the prevalence of cystoid changes, diffuse edema, and unstable fixation among those with dense scotoma (75%, 75%, and 100%, respectively), relative scotoma (20%, 30% and 50%, respectively) and no scotoma (0%, 0% and 0%, respectively) (P <.05). CONCLUSIONS: Macular scotoma was observed by SLO microperimetry in 74% of the patients in this study. A scotoma in CSME is related to the formation of cystoid changes and the type of macular edema. In eyes with CSME in type 2 diabetes mellitus, a scotoma in the macula causes visual acuity impairment and unstable fixation.

Aged↗
PubMedDate not supplied

Reproducibility of the measurements of the optic nerve head topographic variables with a confocal scanning laser ophthalmoscope.

PURPOSE: To determine the optic nerve head topographic parameters with the least variability in repeat measurements. METHODS: We randomly selected and evaluated 1 eye each of 20 healthy subjects, a total of 20 eyes. We used the confocal scanning laser ophthalmoscope (CSLO) for optic nerve head analysis. The disc area and a total of 13 parameters were determined by Top SS. Each subject was examined five times, each time on a different day, during a 2-month period. We obtained a series of five 10 x 10 degrees images for each eye per visit. Three of the five images were randomly selected to create a mean image. Coefficients of variation of each of the 13 variables studied were calculated separately by using those five different optic nerve head topographic measurements. RESULTS: The subjects were 11 women and 9 men. The mean age of the subjects was 30.5 +/- 6.9. The mean optic disc areas were 2.26 +/- 0.39 mm(2) and 1.96 +/- 0.37 mm(2) for the men and the women, respectively (P >.05). The mean coefficient of variation for measurement of the variables was found to range between 1.2% and 9.8%. The variables, cup shape, volume above, average depth, and volume below, were found to yield the best reproducible measurements. CONCLUSION: The CSLO with its highly reproducible measurements (<10% error) offers a highly objective, safe, and effective method for clinical use in measurements of the topography of the optic nerve head. The subtle differences in the variables, cup shape, volume above, average depth, and volume below, may be of vital importance in the follow-up of those diseases requiring longitudinal monitoring of the optic nerve head, namely ocular hypertension and glaucoma.

Adult↗
PubMedDate not supplied

Extrafoveal photostress recovery testing with a scanning laser ophthalmoscope.

We used a modified photostress recovery test (PSRT) with microperimetry in a scanning laser ophthalmoscope (SLO) to evaluate the extrafoveal region. After the red-target threshold was determined, the retina was bleached with argon green laser illumination. Test spots were presented every 3 seconds at the testing point and subjects indicated when they saw the spot. We determined the recovery time in 17 normal subjects under the following conditions: bleaching times of 10, 20, and 30 seconds; spot intensities of 0, 2, and 4 dB greater than threshold; Goldmann I, II, and III spots; and spot locations 7.5 degrees temporal to, nasal to, above and below the fovea, and at the fovea. We also measured recovery times inside and outside the detachment in 11 patients with central serous chorioretinopathy. Recovery time was correlated with bleaching time and spot intensity, but not with the location of spot size in normal subjects. In patients with chorioretinopathy, the recovery time was longer inside than outside the detachment. This technique is useful for measurement of photostress recovery time at extrafoveal points, and for comparison of times at various testing points. Results in patients with chorioretinopathy suggest that this technique may be useful for studying the pathophysiology in ocular diseases.

Adult↗
PubMed2003

Patients with AMD and a large absolute central scotoma can be trained successfully to use eccentric viewing, as demonstrated in a scanning laser ophthalmoscope.

Twenty patients with age-related macular degeneration, an absolute central scotoma and a mean visual acuity of 0.04 (20/475) were studied. A scanning laser ophthalmoscope (SLO) was used for microperimetry and determination of preferred retinal locus, often located to the left of the retinal lesion (corresponding to a location to the left of the visual field scotoma), which is considered unfavorable for reading. All 20 patients were trained to use a new and more favorable retinal locus for reading, above (or occasionally below) the retinal lesion (corresponding to a location below or above the visual field scotoma), first by reading scrolled text under simultaneous fixation monitoring and instruction in the SLO and then by reading printed text, using high magnification (mean 14.3x). For the 18 patients who learned to use eccentric viewing, reading speed with adequate magnification prior to training was 9.0+/-5.8 words/min. With training (mean 5.2 hours), it increased significantly (p<0.001) to 68.3+/-19.4 words per min. Training of eccentric reading has thus proved to be very successful.

Aged↗
PubMed1997

Local photoreceptor alignment measured with a scanning laser ophthalmoscope.

The aim of this study was to develop a fast test for local photoreceptor alignment. Photoreceptor alignment is an important indicator of retinal integrity. Digitized images of fundus reflectance were obtained for 20-30 pupil entry positions with a custom built scanning laser ophthalmoscope (SLO). The data permitted the calculation of curve peakedness of the optical Stiles-Crawford effect (SCE) as a function of retinal location. We found that the peakedness is low in the central 0.5 deg, reaches a maximum at an eccentricity of 1-2 deg and gradually drops with increasing eccentricity. These data are in conformity with the anatomy of foveal cones. Additionally, the psychophysical SCE was measured with red light and an 8 deg stimulus. The mean peak position of the SCE in the pupil plane for both methods was similar, but the optical SCE was clearly steeper. The SLO provides a fast, reliable and objective way to determine local receptor alignment in the central retina.

Adolescent↗