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A new technique of binocular indirect ophthalmoscopy uses a Finhoff transilluminator, held between the observer's eyes, as the light source. The light is focused in the patient's dilated pupil through a condensing lens in a darkened room and the image is seen stereoscopically. The advantages and limitations of this technique and the optical principles are highlighted.
The author presents an optimized method of bio-ophthalmoscopy using new Russian aspherical high-diopter lenses +60.0, +75.0, and +90.0 diopters, supplied with photoprotective filters. Excellent characteristics of the lenses ensure a perfect stereoscopic picture of a large site of the fundus oculi and of the intraocular cavity making use of slit lamps of any design. Various chorioretinal abnormalities, including the very initial changes, are easily diagnosed. The method is rather simple and ergonomic. An appreciable advantage of high-diopter aspherical lenses is the possibility of using them in coagulative contact-free laser interventions on the fundus oculi, which may be performed, primarily, in cases with peripheral abnormalities which are difficult to examine using the traditional Goldman's type lenses. Methods of working with the new optical elements are described in brief and recommendations on their practical use are offered.
Lesions of the optic tract produce a distinctive pattern of optic atrophy and visual field loss and may be due to either congenital or acquired causes. We report a case of a congenital optic tract syndrome and correlate the magnetic resonance imaging findings with the appearance of nerve fiber layer defects found by confocal scanning laser ophthalmoscopy.
UNLABELLED: The diagnosis of the open angle glaucoma in myopic eyes remains one of the major problems, as the changes of the optic head in myopia may be similar to glaucomatous changes. The aim of the study was to analyse biomorphometric parameters of the optic nerve head in myopic eyes with glaucoma with scanning laser ophthalmoscope from Laser Diagnostic Technologies Inc. There was 29 children examined and among them 12 children with glaucoma and myopia as a study group (I) and 17 children with myopia as a control group (II). RESULTS: TCA means values; group I: 1.994 +/- 0.158, group II:2.028 +/- 0.200 CD means values; group I; 0.315 +/- 0.072, group II: 0.247 +/- 0.057 Rim means values; group I: 1.366 +/- 0.164, group II: 1.511 +/- 0.136 Vol. A mean values; group I: +0.205 +/- 0.03, group II: +0.83 +/- 0.03 Vol. B mean values; group I: -0.159 +/- 1.608, group II: -0.117 +/- 0.08. Average values of the biomorphometric parameters of the optic nerve head were worse in group I than in group II, but there was not statistical significance between the differences. Scanning laser ophthalmoscopy may be used as very important additional examination in juvenile glaucoma cases with myopia.
OBJECTIVE: To determine the effect of pupil size and cataract on the reproducibility and image quality obtained with confocal scanning laser ophthalmoscopy. METHODS: Three image series were obtained with a confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph, Heidelberg, Germany) before and after pupillary dilation in each of 39 subjects (8 normal subjects, 5 glaucoma suspects, and 26 patients with glaucoma). The cataract density was measured with both a lens opacity meter and the Lens Opacities Classification System III system. The image quality of each image series was subjectively scored on a scale of 0 (poor) to 9 (high) by 2 independent observers who were unaware of the cataract density and pupil size during image acquisition. The image quality and reproducibility were objectively evaluated using the SD of the mean topography image of each subject. RESULTS: The mean pupil diameter in all subjects before and after dilation was 2.5 +/- 0.8 mm and 5.8 +/- 1.4 mm, respectively. After pupillary dilation, both the mean image quality score and mean SD of the mean topography image improved (from 4.5 +/- 3.5 to 7.4 +/- 2.3 and from 48.6 +/- 18.8 microns to 35.6 +/- 15.5 microns, respectively). The quality score of the images that were obtained before pupillary dilation was associated with the pupil size and density of nuclear and posterior subcapsular cataracts. The SD of the mean topography images that were obtained before pupillary dilation increased with a decreasing pupil size (P = .003) and an increasing density of the nuclear (P < .03), cortical (P = .02), and posterior subcapsular (P = .002) opacity. CONCLUSIONS: Although pupillary dilation improved the image quality in most subjects, the improvement was sometimes small. Those subjects with small undilated pupils and/or cataracts may benefit most from pupillary dilation.
A study was designed to validate a functional investigation performed with the scanning laser ophthalmoscope before surgery for macular holes in 12 eyes: The assessment included fundus examination, a functional examination resulting in evaluation of the preferred retinal lows, visual acuity and recording of visual evoked potentials. The preferred retinal locus was evaluated by presenting a small square area, and visual acuity was determined by means of calibrated figures. The visual evoked potentials were evoked by three alternating checkerboards (check size, 30', 2 Hz) centered over the hole and seen at an angle of 6.5 x 6.5 degrees, 2.5 x 2.5 degrees and 6.5 x 6.5 degrees with central exclusion of 2.5 x 2.5 degrees. The appearance of the fundus visualized by scanning laser ophthalmoscopy consisted of a clear central disk corresponding to the hole, surrounded by a very dark ring, associated with a second, less dark ring with unclear margins. Fixation was unstable in one case with a visual acuity of 20/70. In 11 cases, fixation was localized to the superior retina with a visual acuity superior to 20/70. The visual evoked potentials evoked by 6.5 x 6.5 degrees were discernible in all 12 eyes; visual evoked potential by annular stimuli were discernible in 11 cases. The 2.5 x 2.5 degrees stimulus evoked no response in eight cases, proving the area of the hole was nonfunctional. A response was recorded in the four other cases, where the dimension of the holes was less than 2 degrees. The results of this scanning laser ophthalmoscopic assessment demonstrated a precise evaluation of the residual macular function in the cases of full-thickness macular holes.
BACKGROUND: The aim of our study was a detailed morphological and functional assessment of macular foramen stages II-IV by scanning laser ophthalmoscopy (SLO) and fundus perimetry including a correlation with clinical findings. METHODS AND MATERIALS: Included in this prospective study were 78 patients where SLO imaging and fundus perimetry were performed with the SLO-105 (Rodenstock) prior to pars plana vitrectomy for macular foramen on one eye. Both the size and shape the of macular foramen were assessed. Deep (0 dB) and relative (12 dB) scotomata were tested using the Goldmann II stimulus in the 20 degrees field of the SLO. Imaging was performed with the infrared laser and confocal aperture C2. RESULTS: The size of macular foramen ranged from 140 microns to 800 microns (median: 420 microns) and 20 (26%) had irregular, polycyclic borders. In 21 patients (27%) a bright sector could be seen just outside the hole. Deep scotomata were notably smaller than the visible macular hole in 4 patients (6%) and 18 deep scotomata (25%) extended beyond the hole. There was a weak inverse correlation between the size of deep, relative scotomata and the diameter of the macular holes with the visual acuity (r = -0.46; r = -0.39 or r = -0.53), but no correlation with the duration of symptoms could be demonstrated. CONCLUSION: Polycyclic borders were seen as a new feature of some idiopathic macular foramen. This may be due to asymmetric traction or adhesions on the macular area. Also, deep scotomata either smaller or larger than the visible macular hole were found.
PURPOSE: To investigate the peripapillary region in glaucomatous eyes by indocyanine green angiography. METHODS: Indocyanine green angiography of the optic disk and peripapillary region was evaluated by modified confocal scanning laser ophthalmoscopy in 22 eyes of 22 patients with glaucoma and in 10 normal eyes of 10 control patients with unilateral choroidal melanoma. The occurrence and extent of indocyanine green angiographic anomalies were correlated with optic disk morphology and the severity of glaucoma. RESULTS: In the 32 eyes of 32 patients, two types of peripapillary defects were identified in the late-phase angiograms. The first was hypofluorescent areas in the peripapillary region and was more common in eyes with glaucoma (P < .02); their occurrence and extent correlated with age (P < .01). In nine of the 17 eyes, alpha (peripheral) zone peripapillary atrophy corresponded with the areas of peripapillary indocyanine green hypofluorescene. The second defect, hypofluorescent halos adjacent to and extending around the full circumference of the optic disk margins, did not correlate with any of the study factors. CONCLUSIONS: Indocyanine green angiography showed areas of hypofluorescene in the peripapillary region in late-phase angiograms in 68% of glaucomatous eyes compared with 20% of control eyes. These hypofluorescent areas might be either of result of blockage of background fluorescence by pigment or caused by an absence of vascular tissue (choriocapillaris).
The combination of a high minus setting of the ophthalmoscope and an extra positive lens in front of the patient's eye forms a Galilean telescope that increases magnification in direct ophthalmoscopy. The telescope magnification equals the ratio between objective and ocular focal lengths.
The goal of the present study was to analyze the interaction between incident laser light and retinal tissue in confocal scanning laser ophthalmoscopy and tomography. We examined the change in axial intensity distribution during evaluation of the retinal surface topography in macular and optic nerve head evaluation in normal volunteers and patients with different retinal diseases. Additionally, we examined a model eye with a model cyst and human globes in an eye mounting chamber. We found that confocal scanning laser tomographs record specular reflected light originating from intraocular surfaces as well as light scattering from deeper retinal structures. Concave and convex retinal surfaces and eye movements may influence accurate topographic detection. Knowledge of the exact mechanism of image formation in confocal tomography is of great importance for the understanding of validity of these measurements. Proper identification of observed artifacts and preventive measures will increase the utility, reproducibility, and validity of this technology.
A newly developed, anatomically shaped indirect ophthalmoscopy lens is described. Outstanding features of this lens are its low weight and superiority for examining the fundus in patients with particular anatomical abnormalities or pathologic disorders (e.g., an extremely high bridge of the nose, or paralytic strabismus).
New techniques with special filters for ophthalmoscopy and angioscopy are described and discussed. An apparatus with light source, light transmission by fiber optics and with a direct and an indirect ophthalmoscope is presented.
A new attachment that can be used with optimized ophthalmoscopes is described. Readily removable and interchangeable eyepieces containing small, lightweight Galilean telescopes approximately double the magnification. The influence of this device on some of the optical properties of binocular indirect ophthalmoscopy including magnification, field of view, brightness of the fundus image, and stereopsis, are reviewed briefly.
A new method for quantifying fixational eye movements by scanning laser ophthalmoscopy was developed and the method was evaluated in ten normal persons. Video sequences of the ocular fundus obtained during fixation were recorded, and linear movements of the fovea between successive video frames were transformed to angular movements of the eye by an algorithm that takes into account the individual optical properties of the eye. A computer program was developed to automatically calculate the amplitude, the direction, and the duration of the angular movements together with the precision of each of these estimates. Two types of eye movements could be recognized in normal persons; a fast type (saccades) which was initiated and terminated within one video frame (20 msec), and a slow type (drifts) which lasted more than 8 video frames (160 msec). The mean amplitude of the fast movements (0.41 degrees) was significantly higher than the mean amplitude of the slow movements (0.31 degrees). The methods was found to be suitable for quantifying fixational eye movements in clinical trials while simultaneously visualizing the ocular fundus. However, by refining the determination of the foveal position on the SLO images the precision of the method can be further improved.
A simple device is described which both facilitates and significantly extends the scope of indirect ophthalmoscopy.
OBJECTIVE: To evaluate the efficiency of scanning laser ophthalmoscopy (SLO) on detecting retinal nerve fiber layer defects (RNFLD). METHODS: 95 eyes with primary open angle glaucoma, 37 ocular hypertension, 83 glaucomatous suspect and 34 normal eyes were investigated by SLO to evaluate the retinal nerve fiber layer (RNFL). Recording tapes of 68 eyes were re-investigated by two investigators for estimating the intra- and inter-observer agreement. RESULTS: The intra- and inter-observer agreement of the presence and types of RNFLD was fairly good (Kappa values were 0.66 - 0.76 and 0.59 - 0.65 respectively). The sensitivity and specificity in detecting RNFLD by SLO were 80.0% and 94.1% respectively. CONCLUSION: The evaluation of RNFL by SLO is a quick, accurate and safe method. It may be clinically useful in the diagnosis of glaucoma.
The appearance of the peripapillary retinal nerve fiber layer (PRNFL) is crucial in the evaluation of patients with presumed optic neuropathies as well as in the differentiation of true optic disc edema from pseudopapilledema. Monochromatic (red-free) photography performed at 2 + magnification with a Zeiss fundus camera, a filter with maximum transmission at 540 nm, and Kodak Plus-X black-and-white film provides excellent PRNFL detail. Since direct ophthalmoscopy depends upon maximum illumination, which in turn depends upon increased color temperature of the light source, use of a direct ophthalmoscope with a gas-surrounded tungsten filament light source driven at 4.5 V raises color temperature sufficiently to allow practical use of monochromatic, red-free filters for optimum PRNFL evaluation.
OBJECTIVE: To examine racial differences in optic disc topography among ocular hypertensive participants in the Ocular Hypertension Treatment Study. METHODS: Four hundred thirty-nine participants from 7 Ocular Hypertension Treatment Study centers who had good-quality baseline images obtained using a quantitative 3-dimensional confocal scanning laser ophthalmoscope, the Heidelberg Retina Tomograph (Heidelberg Engineering, Dossenheim, Germany), were included in this study. The first 10 degrees- or 15 degrees-field of view mean topographic image acquired was included in all analyses. Differences in Heidelberg Retina Tomograph topographic optic disc parameter measurements by self-identified race were assessed using a mixed-effects linear model to control for confounders and for the use of both eyes in the model. RESULTS: By self-attribution, 74 (17%) of the 439 participants were of African origin, 329 (75%) were white, 24 (5%) were Hispanic, and 12 (3%) were Native American, Native Alaskan, Asian, Pacific Islander, or unknown. The African American participants had statistically significantly (P<.001) larger mean (SD) optic disc areas than the other participants, 2.17 (0.41) mm(2) vs 1.87 (0.38) mm(2), respectively. African American participants had a larger cup area, cup volume, cup depth, neuroretinal rim area, rim volume, and smaller rim-optic disc area ratios than the other participants. No difference between African American and the other participants was found for cup shape and retinal nerve fiber layer thickness. After controlling for optic disc area, none of the differences between African American and the other participants found in the univariate analysis remained statistically significant (P>.10). CONCLUSIONS: This study demonstrated in a large cohort of subjects with ocular hypertension, that African Americans have significantly larger optic discs, optic cups, neuroretinal rims, and cup-disc ratios than other racial groups. Furthermore, this study found that differences in topographic optic disc parameters between African Americans with ocular hypertension and other racial groups are largely explained by the larger optic disc area in the African Americans. These results highlight the need to consider race and optic disc size when evaluating the appearance of the optic disc in glaucoma.