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The first useful table model ophthalmoscope was designed by Donders and the instrumentmaker Epkens. With the use of this instrument Donders' pupil Van Trigt made the first drawings of the normal and pathological fundus of the eye. His contribution was of great importance for the early diffusion of knowledge of the fundus of the eye.
Portable indirect ophthalmoscopy is a useful adjunct to field surveys and rural eye care in developing nations. The method for converting an electrically-powered indirect ophthalmoscope to a portable battery-powered unit is described.
A binocular indirect ophthalmoscope argon laser delivery system was used to treat 100 selected patients with a variety of retinal disorders. The laser was found to be particularly valuable in photocoagulating the retinal periphery, because scleral depression could easily be performed simultaneously. Furthermore, laser treatment was facilitated in eyes that dilated poorly, such as those with rubeosis iridis, and eyes with focal lens opacities requiring panretinal photocoagulation. Infirm or anesthetized patients who could not sit at a slit lamp could also be treated. Disadvantages included difficulty in accurately aiming the laser beam and instabilities inherent in the system that make it unsuitable for the treatment of macular diseases.
We have developed an automatic filter for the indirect ophthalmoscope that protects the physician's eye from potential damage during laser treatment. The laser light is applied through an endolaser probe using indirect ophthalmoscopy.
Effective use of diagnostic drugs in primary eye care demands that the optometrist not only be able to better utilize conventional equipment, but also utilize new equipment. This paper offers a simple and straightforward discussion of the Binocular Indirect Ophthalmoscope (BIO). Optical principles, clinical advantages and disadvantages, clinical indications for the instrument, and instrument technique are discussed. A suggested reading list is also presented.
Recommendations for the design of binocular indirect ophthalmoscopes are made based on a comparative analysis of the optics of various indirects currently available. Significant differences were found to exist in the areas of brightness, stereopsis, small pupil capability, and PD ranges among the brands under study.
We evaluated the stability of fixation in 38 healthy eyes (N), 30 eyes with macular degeneration (AMD) and 20 eyes with juvenile macular dystrophy (JMD) during our newly developed automated full-threshold static perimetry using the scanning laser ophthalmoscope (SLO). The point of fixation was recorded for each stimulus presentation. After the examination, the mean fixation point (MFP) as well as the standard deviation from the MFP, the examination time, and the reaction time were evaluated. Healthy eyes did not show a mean SD of more than 0.7 degree from the center of gravity of fixation with one exception. There was only poor correlation between age and deviation from the MFP (r = 0.09 for N; r = 0.18 for AMD; and r = 0.18 for JMD), whereas the correlation between visual acuity (VA) and deviation from the MFP was slightly better (r = 0.22 for N; r = 0.34 for AMD; and r = 0.52; P < 0.02 for JMD). Eyes with functional impairment mostly showed instable fixation (deviation, > 3 degrees), which was observed even in two patients with only slightly diminished VA of 20/25. However, stable fixation was observed in isolated cases even when VA was reduced to 20/100. The deviation of fixation was more pronounced horizontally than vertically in normals (0.40 degree:0.31 degree) and in patients suffering from AMD (0.88 degree:0.68 degree), whereas eyes with macular dystrophy did not show this phenomenon (0.82 degree:0.82 degree). The results demonstrate that there is the possibility of stable fixation even in eyes with a decrease in VA due to morphological changes in the macula.(ABSTRACT TRUNCATED AT 250 WORDS)
BACKGROUND: Documentation of the retinal nerve fiber layer using red free light is not established as a routine method. The reasons for this are the difficulties involved in taking the pictures and developing them, especially in glaucoma patients, and the need for maximum pupil dilation. The scanning laser ophthalmoscope (SLO) allows fast and easy documentation of the fundus with the possibility of simultaneous image control during the examination. PATIENTS AND METHODS: Nerve fiber layer images of 48 eyes of 25 patients taken with the argon blue light of the SLO were compared to conventional photographs of the nerve fiber layer with red-free light. In addition, we compared documentation of the nerve fiber layer using argon-blue or argon-green light in the SLO. RESULTS: The nerve fiber layer images obtained with the SLO were of good quality for all 48 eyes included in the study, whereas with conventional photography we could not obtain images in 9 eyes. There was a high correlation between the two methods in the detection of localized damage or zones with diffuse nerve fiber atrophy for the 39 eyes documented with both methods, and there was better image quality in some using the SLO. The use of blue light permits the nerve fiber layer to be seen more easily than with green light. CONCLUSIONS: The SLO allows nerve fiber bundle defects or diffuse atrophy to be detected similar to conventional fundus photographs using red free light sources. There is no further need to dilate the pupil maximally due to the confocal principle and the scanning technique. The smaller angle of view of the SLO requires fixation movements of the patient being examined for the detection of beginning peripheral nerve fiber bundle defects.
PURPOSE: To present a new method of performing scanning laser ophthalmoscope perimetry that compensates for eye movements so that the correct retinal location is tested even if fixation changes. This allows for accurate testing of patients with central scotomas and for repeating testing longitudinally at the same retinal locations even if central fixation is lost. METHODS: The operator views the retina and selects a retinal landmark, such as a vessel bifurcation, that can be identified easily. A testing strategy is preselected, and the computer saves the landmark and stimulus coordinates. To present each stimulus, the operator positions a cursor over the retinal landmark, and the computer adjusts the site of presentation of the stimulus for any change in landmark position caused by an eye movement. At the conclusion of the testing, the results are displayed in the proper retinal location on a fundus image. RESULTS: Sixty-seven eyes with macular disease were tested with the landmark-driven method, using the same preplanned strategy for each eye for both a bright and a dim stimulus. There was a low rate of inconsistent points (seen with dim but not bright stimuli), and virtually all of these bordered a dense scotoma. Those eyes with more inconsistent points had a significantly greater percentage of dense scotoma points and significantly lower visual acuity. The technique significantly corrected error in retinal localization resulting from large eye movement. There is no significant rotation or magnification change during the procedure, so specifying the change in location of one landmark is sufficient to describe movement of the retina. The technique is rapid and easy to administer to elderly patients and to children. CONCLUSIONS: This technique allows for accurate and repeatable measures of retinal sensitivity in specific locations. It is useful in following change over time. It can be developed further to allow for fully automated, retinally correct testing.
To improve the differential diagnosis of macular breaks by microperimetry using the scanning laser ophthalmoscope (SLO), we studied 50 consecutive breaks detected by biomicroscopy and indirect ophthalmoscopy. The full-thickness macular break was easily diagnosed using only biomicroscopy and indirect ophthalmoscopy because the macular break had a cuff in 22 of the eyes. SLO microperimetry also showed an absolute scotoma within the macular break and a relative scotoma on the cuff in these 22 eyes. However, in the other 28 eyes it was impossible to distinguish between the full-thickness macular breaks and pseudo-macular breaks or lamellar macular breaks using only biomicroscopy and indirect ophthalmoscopy because of the absence of a cuff. However, SLO microperimetry differentiated full-thickness macular breaks from pseudomacular breaks or lamellar macular breaks in these 28 eyes. SLO microperimetry is indispensable for determining the prognosis of and the surgical indication requirements for idiopathic macular breaks.
PURPOSE: Angioscotomas are scotomata caused by vessel shadows. Their extent may be influenced by physiological and pharmacologic conditions and disease. In this study, the authors quantified angioscotomas in normal subjects using a fundus perimetry technique with a scanning laser ophthalmoscope. They further investigated the influence of two different wavelengths on scotoma depth. METHODS: For blue-on-yellow perimetry, the authors used two different lasers--an argon laser (lambda = 458 nm) for stimuli and a low background and a HeNE (lambda = 594 nm) for a superimposed yellow background. For red-on-red perimetry, the authors used another HeNe laser (lambda = 633 nm). Fundus illumination was provided by an infrared light. Five healthy subjects were examined. Twenty-one to 24 stimuli (200 msec duration, 0.4 degree x 0.4 degree) were presented at different intensities in randomized order in a 5 degrees x 2.5 degrees retinal test field, directly inferior and adjacent to the disk. RESULTS: The depth of scotomas caused by major vessels varied in all subjects and depended on perimetry condition. To quantify the influence of vessels on sensitivity, the authors analyzed psychometric functions for stimuli projected on the vessels and for those far from the vessels. The authors found a significant difference for targets on the vessel compared to those far, which was more pronounced for the blue-on-yellow condition. CONCLUSIONS: Angioscotomas are detected better with blue targets on a yellow background than with red-on-red perimetry. The greater light absorption by hemoglobin and oxyhemoglobin at short wavelengths compared to longer wavelengths is not compensated for by visual mechanisms.
PURPOSE: To image and quantify the spatial distribution of fundus autofluorescence in normal subjects, to determine its age dependence, and to document the deviation from normal in patients with age-related macular disease. METHODS: Using a confocal laser scanning ophthalmoscope (cLSO), the intensity and spatial distribution of fundus autofluorescence was studied in 33 normal subjects, 97 eyes with drusen only, and 111 eyes with visual loss caused by age-related macular disease. RESULTS: Fundus autofluorescence intensity in normal subjects was highest at the posterior pole and dipped at the fovea. Autofluorescence increased with age at the posterior pole. Fundus in eyes with age-related maculopathy showed localized high autofluorescence that did not correspond with drusen. Linear pigmentation at the level of the retinal pigment epithelium (RPE), whether detached or flat, fluoresced brightly, whereas plaques of melanin did not. Areas of low and high levels of autofluorescence were seen in lesions containing choroidal new vessels. In areas of geographic atrophy, autofluorescence was low. CONCLUSIONS: The spatial distribution of background fundus autofluorescence and the correlation of autofluorescence with age in normal subjects imply that autofluorescence is derived from lipofuscin at the level of the RPE. Focal accumulation of autofluorescent material occurs at the level of the RPE in patients with drusen, but the drusen do not show marked increases in autofluorescence. It is likely that melanolipofuscin accounts for the high levels of autofluorescence, corresponding to linear pigmentation at the level of the RPE. Low-intensity autofluorescence occurs in the presence of retinal photoreceptor loss, and variable levels over disciform lesions probably relate to variations in metabolic activity of the RPE.
The purpose of this study was to test the usefulness of the scanning laser ophthalmoscope (SLO) as a stimulator for localized contrast-sensitivity (CS) measurements under visual control in normals and glaucomatous patients. The helium-neon laser (630 nm) of a Rodenstock SLO was used to generate a localized square-wave stripe pattern and a fixation mark while an infrared laser (780 nm) visualized the eye's fundus. Thus, measurements with unstable fixation could be discarded. The spatio-temporal CS was determined with a localized alternating pattern as follows: 5 Hz, 2.88 cycles/degree; stimulus diameter 2 degrees; test location central, temporal upper, and temporal lower retinal area. The subjects included 47 controls, 23 ocular hypertensive patients (intraocular pressure > 21 mmHg, normal optic disc, no visual field defect), 27 "preperimetric" glaucoma patients (intraocular pressure > 21 mmHg, early glaucomatous optic disc damage, no visual field defect), and 41 "perimetric" glaucoma patients with glaucomatous defects of the optic disc and perimetric losses. Nonparametric tests (Wilcoxon, Spearman) were used for statistical analyses. Among the three locations tested, CS values recorded for the temporal lower retinal areas showed the strongest reduction in glaucomas ("preperimetric" P = 0.002, "perimetric" P < 0.0001) and a significant correlation with the perimetric mean defect of the stimulated area (r = 0.65, P < 0.001). In all, 95% of glaucomatous eyes with extensive visual field losses were recognized as pathologic at a specificity of 80%. Spatiotemporal CS of temporal retinal areas is sensitive to glaucoma. The present study confirms the feasibility of using the SLO system for localized CS measurements, in normals and patients.
I have developed two protective caps that fit on the viewing windows of the indirect ophthalmoscope. These caps contain filters that absorb the argon laser beam and protect the operator's eyes during endolaser treatment.
Laser indirect ophthalmoscope (LIO) photocoagulation and transscleral photocoagulation through the conjunctiva and subconjunctiva were performed in the fundus of chinchilla gray rabbits using various exposure times and powers, and the thresholds for retinal blanching and choroidal hemorrhage were determined. The therapeutic range was described for both applications as the ratio between energy values to produce grayish white lesions and hemorrhage at 50% probability. The therapeutic range appeared to remain almost constant with different exposure times. The mean ratio with LIO was 3.2 +/- 0.28, similar to that with slit-lamp delivery reported in our previous study. The mean ratio with transscleral photocoagulation through the conjunctiva and subconjunctiva were 2.48 +/- 0.28 and 2.38 +/- 0.26, respectively. The variability of LIO appeared to be a little lower than with transscleral photocoagulation. There was no significant difference between the variability with transscleral photocoagulation through the conjunctiva and subconjunctiva.
The authors studied the short-term impact of combined episcleral iodine-125 plaque radiotherapy and argon laser treatment in a series of 24 patients with choroidal malignant melanoma. All patients underwent plaque therapy prior to their initial laser session. All laser treatments were performed with an indirect ophthalmoscope argon green laser, using low-power, long-duration exposures. The endpoint of laser therapy was a well-defined atrophic circumbasal chorioretinal laser scar and complete or nearly complete nonfluorescence of the lesion on fluorescein angiography. In a case-by-case matched comparison study, the authors evaluated the relative local regression of tumors treated by combined plaque-laser therapy, iodine-125 plaque therapy alone, and cobalt-60 plaque therapy alone. The tumors treated with supplemental laser regressed substantially faster and more completely than did those treated by either type of plaque therapy alone. However, the short-term visual loss was greater in eyes treated by the combined therapy.
The pathophysiological influence of spontaneous carotid cavernous fistula (CCF) on retinal/orbital circulation is discussed. Of 20 patients, 1 case of papilloedema, 4 of choroidal detachment (CD), 2 of exudative retinal detachment (ERD) and 3 cases of central venous thrombosis (CVT) were seen, associations that on rarely reported in the literature. An elevation in the episcleral venous pressure was measured that was more than twice the normal, which explains the ophthalmoscopic findings.
OBJECTIVE: To evaluate a short educational intervention instructing primary care physicians in the recognition of glaucomatous changes of the optic disc. DESIGN: Comparison of performances on a pretest and a posttest consisting of fundus slides in color. SETTING: Educational conferences at two university-affiliated teaching hospitals and one staff-model health maintenance organization. SUBJECTS: Thirty-six internal medicine residents and ten practicing internists. INTERVENTION: A 20-minute slide/narration educational program, which covered diagnostic criteria for open-angle glaucoma, normal and abnormal optic disc anatomy, and funduscopic signs of open-angle glaucoma. MEASUREMENTS AND MAIN RESULTS: Following the intervention, residents showed improved sensitivity (0.76 to 0.88, p = 0.007), specificity (0.65 to 0.88, p less than 0.001), and accuracy (0.71 to 0.88, p less than 0.001). Internists showed similar increments in sensitivity, specificity, and accuracy: 0.67 to 0.86 (p = 0.01), 0.59 to 0.84 (p = 0.01), and 0.63 to 0.85 (p = 0.002), respectively. CONCLUSION: A brief educational intervention can result in meaningful improvement in physician diagnostic accuracy in recognizing ophthalmoscopic signs of open-angle glaucoma.