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PubMed1985

Hereditary retinal degeneration in the Abyssinian cat: correlation of ophthalmoscopic and electroretinographic findings.

Ophthalmoscopic and electroretinographic (ERG) findings were correlated in a group of Abyssinian cats affected by a slowly progressive and hereditary retinal degenerative disease. According to ophthalmoscopic findings the disease was divided into stages. At stage 1 and 2 retinal changes were minor; showing a gray discoloration most often in the peripheral and midperipheral tapetal fundus. At stage 3 discoloration was generalized and there was marked vascular attenuation. A generalized retinal atrophy was found at stage 4. ERG recordings showed an abnormally depressed stimulus response curve for the b-wave at stage 1 of disease when 30-Hz cone flicker responses were indistinguishable from normal. With progression of disease there was a successive decrease of a- and b-wave amplitudes before there was a significant reduction also of the c-wave amplitude (first seen at stage 3). The ERG was nonrecordable at stage 4. These findings suggest that the photoreceptors are affected primarily by the disease, before there is a functional involvement also of the pigment epithelium. The rod system seems to be affected early in the disease as compared with the cone system. A staging of the disease by ophthalmoscopy correlated more to the function of the rods than to that of the cones.

Animals↗
PubMed2003

Macular pigment density in healthy subjects quantified with a modified confocal scanning laser ophthalmoscope.

BACKGROUND: In the industrialized world age-related macular degeneration (ARMD) is the leading cause for legal blindness beyond the age of 65 years. Recent studies indicate that the density of the macular pigment (MP) may play a central role in the development and progression of age-related maculopathy (ARM). We present results of measurements of macular pigment density (MPD) with a modified confocal scanning laser ophthalmoscope and compare macular pigment density values obtained from reflectance and autofluorescence images in healthy subjects. METHODS: A modified confocal scanning laser ophthalmoscope (Heidelberg Engineering, Heidelberg) was optimised for fundus reflectance and autofluorescence images at 488 nm and 514 nm. For autofluorescence imaging a band pass barrier filter with a short wavelength cut off at 530 nm was used. MPD maps were obtained, and MPD was evaluated within two degrees around the foveal center. In this study we included 109 healthy subjects aged from 18-75 years. RESULTS: Average MPD ranged between 0.16 density units (D.U.) and 0.22 D.U. depending on the techniques used for the measurement. Using the reflectance method the mean MPD was 0.16+/-0.06 D.U., whereas a MPD of 0.22+/-0.07 D.U. resulted from autofluorescence images with the 530-nm barrier filter. CONCLUSIONS: This study demonstrates the good feasibility of MPD measurements with a modified confocal SLO. In agreement with previous studies we found higher macular pigment density values calculated from autofluorescence images than from reflectance images. We could not find any differences in MPD related to age and gender. Prospective longitudinal studies to verify the influence of MPD on the development and progression of ARM are needed.

Adolescent↗
PubMed1993

Stereoscopic photography with a scanning laser ophthalmoscope.

Digital fundus angiography has advantages over conventional photography. However, digital angiography as it is normally performed, provides no stereoscopic information. Because stereoscopic data can be crucial in the evaluation of conditions such as age-related macular degeneration, we developed methods to record stereoscopic information during video angiography with a scanning laser ophthalmoscope and to produce high-quality static stereoscopic images. Stereoscopic information was collected by moving the scanning laser ophthalmoscope side-to-side and with a modified Allen separator. Stereoscopic images were displayed as stereoscopic pairs on 35-mm film, stereoscopic pairs from a digital printer, and as stereoscopic images directly on a conventional video monitor. This system to capture and display stereoscopic information is convenient, uses readily available technology, and can be adapted to any digital angiography system.

Fluorescein Angiography↗
PubMed1998

Examination of patients with cystoid macular edema using a scanning laser ophthalmoscope with infrared light.

PURPOSE: To report a noninvasive method for evaluating eyes with cystoid macular edema. METHODS: We obtained infrared images of cystoid macular edema in eight eyes of eight patients using a scanning laser ophthalmoscope with the dark-field mode of a 780-nm diode laser. Differences between infrared images and fluorescein angiograms in the imaging of cystoid changes were examined. RESULTS: With the scanning laser ophthalmoscope, we observed cystoid macular changes as images that resembled three-dimensional pictures in the dark-field mode with infrared light. Cystoid changes observed by this method generally agreed with changes observed by fluorescein angiography. CONCLUSIONS: Scanning laser ophthalmoscopy with infrared light in a dark-field mode is noninvasive, and the results in eyes with cystoid macular edema generally agreed with results obtained by fluorescein angiography. This method is useful for examining eyes with cystoid macular edema.

Adult↗
PubMed1993

Assessment of vision in idiopathic macular holes with macular microperimetry using the scanning laser ophthalmoscope.

BACKGROUND: Visual loss in eyes with full-thickness macular holes has been thought to be due to the absence of retinal function in the area of neurosensory defect as well as loss or reduction of retinal function in the surrounding area of neurosensory retinal detachment. With the advent of surgical techniques to treat macular holes, it is increasingly important to better characterize this visual dysfunction. METHODS: Thirty eyes of 30 patients with full-thickness idiopathic macular holes were evaluated with microperimetry using the scanning laser ophthalmoscope to detect and quantitate absolute and relative scotomata within the central 40 degrees of visual field. A log 2 scale of test stimulus intensities was established. Results of microperimetry were compared with best-corrected visual acuities as measured on the logarithmic Early Treatment of Diabetic Retinopathy Study chart as well as duration of symptoms. RESULTS: All 30 eyes showed an absolute scotoma in the area of neurosensory defect as well as surrounding relative scotomata in the area of neurosensory detachment. Best-corrected visual acuity was correlated with the size of the absolute and relative scotomata (P < 0.002). The sizes of the scotomata were correlated with the duration of symptoms of the macular holes (P < 0.05). CONCLUSION: Microperimetry using the scanning laser ophthalmoscope demonstrates that the visual loss associated with macular holes is related to the reduction of retinal function in the area of the surrounding neurosensory detachment as well as the absence of retinal function in the area of neurosensory defect. The size of the scotomata, determined by microperimetry, is correlated with the patient's visual acuity as well as the duration of symptoms of the macular hole.

Adult↗
PubMed1997

[Ophthalmoscopic evaluation of ocular fixation in children up to 2 years old].

BACKGROUND: The examination of fixation on the fundus oculi is one of the main points in the diagnosis of amblyopia. Therefore it is necessary to describe the fixation ability and to clarify at what age children can fixate foveally and at what age this examination can be carried out, considering not only physiological aspects, but also co-operation reasons. PATIENT AND METHODS: Fixation on the fundus oculi was examined in 111 children aged between 1 and 25 months with the ophthalmoscop-star. This examination was carried out in 64 cases by a second and in 15 cases by a third examiner on the same day. RESULTS: During the first 3 months of age children cannot fixate foveally, one can observe instead, a kind of scatter at the posterior pole in a diameter of about 5 degrees. In the course of the 4, and 5, month of age foveal fixation develops. Repeated examinations of the same child on the same day by a 2, and 3, examiner reveal a very high rate of accordance (78%) of their results. CONCLUSIONS: The examination of fixation on the fundus can be carried out at 4 to 5 months of age. At that age one can differentiate quite reliable between a foveal and eccentric fixation as well as scatter at the posterior pole. The rate of accordance 78% with this fixation examination by several examiners shows that same reliability of this examination carried out in school children and adults. Comparing this result with fixation examination carried out with the Haidinger brushes then one must calculate with a fault rate of about 20% when examining with the ophthalmoscope, considering that the examination with Haidinger brushes as a reference examination.

Adult↗
PubMed2001

Theoretical bases of non-ophthalmoscopically visible endpoint photocoagulation.

Laser photocoagulation is a photothermal process in which heat is produced by the absorption of laser energy by targeted tissues. The purpose of the treatment is to induce thermal therapeutic damage, which causes biological reactions and ultimately beneficial effects. The current endpoint of laser photocoagulation of the chorioretina is an ophthalmoscopically visible retinal whitening. Retinal blanching is the sign that the retina itself has been thermally damaged and results in a number of undesired adverse events. The mechanisms underpinning the efficacy of laser photocoagulation are still poorly understood. However, recent hypotheses postulate that full thickness retinal damage may not be needed to obtain beneficial therapeutic effectiveness. Preliminary studies with laser photocoagulation on animals demonstrated the ability to create therapeutic lesions confined around the Retinal Pigment Epithelium (RPE) cells without causing apparent damage to the overlying retina. The laser impacts were not visible by slit lamp biomicroscopy at the time of laser delivery. Recent experiments showed that the beneficial effect of retinal photocoagulation is mediated by factors derived from the RPE. Non Ophthalmoscopically Visible Endpoint Photocoagulation (NOVEP) protocols might allow treatments that confine minimal therapeutic damage around the cells of the RPE and minimize the damage to the neurosensory retina.

Humans↗
PubMed1998

Scanning laser ophthalmoscope microperimetric assessment in patients with successful laser treatment for juxtafoveal choroidal neovascularization.

PURPOSE: To evaluate fixation stability and changes in retinal function in patients with laser scar expansion after successful macular photocoagulation for juxtafoveal choroidal neovascularization (CNV). METHODS: A consecutive series of 35 patients was examined in this prospective study. Only patients who had been successfully treated with laser photocoagulation for juxtafoveal CNV and who could be followed over a period of at least 6 months were enrolled. Fixation stability and localized light sensitivity were examined by microperimetry using a scanning laser ophthalmoscope. Visual acuity was measured 2 weeks and 3 and 6 months after the laser treatment. The correlation between changes in the logarithm of the minimum angle of resolution (LogMAR) visual acuity and the distance between fixation and the center of the fovea was evaluated. RESULTS: Of 22 eyes of 20 patients that underwent data analysis, laser scar expansion was observed in 16 (72.7%). Ten (62.5%) of the 16 eyes had relative scotomas corresponding to the expanded laser scars. Mean laser scar expansion ratio was 28.7% in the ARMD group and 109.2% in the myopia group, a statistically significant difference (P < 0.01). The change in LogMAR visual acuity was significantly correlated with the distance of fixation locus from the center of the fovea (r = 0.76). CONCLUSIONS: Laser scars produced by photocoagulation for juxtafoveal CNV may expand and extend into the fovea, causing secondary retinal dysfunction. Scanning laser ophthalmoscopic assessment may be useful in evaluating fixation stability and subclinical changes in retinal function surrounding the laser scars before visual disturbance appears.

Aged↗
PubMed1989

Inter-observer comparisons of ophthalmoscopic assessment of diabetic retinopathy.

Five hundred patients attending a general diabetic clinic were examined ophthalmoscopically both by a non-ophthalmic practitioner (NOP) and by an ophthalmologist. The findings were recorded on separate data sheets and the staging of diabetic retinopathy (DR) and grading of diabetic maculopathy by the NOP is compared with that of the ophthalmologist. Comparisons are made for NOPs collectively and for subgroups of NOPs of different levels of experience in ophthalmoscopic assessment of DR. A profile is presented of DR occurring in this diabetic clinic population. The comparison studies show significant variations in ability of different observer groups and also between observers of the same status. It is concluded that an ophthalmologist is a necessary member of a diabetic care team.

Adolescent↗
PubMed1975

Angioid streaks. I. Ophthalmoscopic variations and diagnostic problems.

Fifty-six patients with angioid streaks were evaluated ophthalmologically. Most had repeated fundus photography and fluorescein angiography during a follow-up period of 6 months to 7 years. The ophthalmoscopic variations and diagnostic difficulties which occurred were noted. In most instances, the angioid streaks were not initially recognized and the patient was referred with another diagnosis. In several cases, the peripapillary, macular, and peripheral changes seen with angioid streaks were found to simulate other better known fundus conditions, resulting in the erroneous diagnosis and improper treatment. In some cases, the angioid streaks were so subtle that they were overlooked and in others they were observed, but initially interpreted as something else. Because of the medical significance of angioid streaks, ophthalmologists should be aware of their variable features. These are discussed, with emphasis upon those subtleties which differentiate angioid streaks from other conditions which they may simulate. On the basis of these observations, an ophthalmoscopic differential diagnosis of angioid streaks is proposed.

Adolescent↗
PubMed1995

Fundus imaging in patients with cataract: role for a variable wavelength scanning laser ophthalmoscope.

AIMS: An investigation was carried out to compare the image quality of the ocular fundus obtained clinically, photographically, and with the scanning laser ophthalmoscope (SLO) at visible and infrared wavelengths in patients with significant cataract. METHODS: Nineteen patients admitted for routine cataract extraction were examined clinically by two independent observers to ascertain cataract type and clarity of fundus view with an indirect ophthalmoscope. Fundus photography and both confocal and direct (non-confocal) SLO imaging at 590 nm, 670 nm, and 830 nm were carried out after pupillary dilatation. Images obtained were graded independently using a recognised grading system. RESULTS: Quality of SLO images appeared to be superior to indirect ophthalmoscopy (p < 0.01) and fundus photography (p < 0.001) when graded subjectively. Quantitative analysis of contrast of retinal vessels demonstrated significantly higher contrast for the SLO compared with digitised fundus photographs at all wavelengths tested (p < 0.001), with highest contrast at 590 nm. Use of a confocal aperture significantly improved vessel contrast but may reduce overall image intensity. CONCLUSIONS: Scanning laser ophthalmoscopy may offer a method to observe and record fine fundus detail in patients who have marked cataract.

Cataract↗
PubMed1996

Measurement of retinal blood flow with fluorescein leucocyte angiography using a scanning laser ophthalmoscope in rabbits.

AIMS: To measure blood flow in the rabbit retinal circulation with fluorescein leucocyte angiography using a scanning laser ophthalmoscope. METHODS: Blood was withdrawn from the ear vein of a rabbit (New Zealand White), mixed with fluorescent dye in a test tube and centrifuged. The yellow-brown layer containing fluorescein stained leucocytes was collected and injected into the ear vein of the same rabbit while performing fluorescein angiography with a scanning laser ophthalmoscope. The image of retinal angiography displaying circulating fluorescent leucocytes was recorded on video tape. From each frame of the video tape, the consecutive positions of fluorescein stained leucocytes were digitised using an image analysis system and the velocity of blood flow was calculated. RESULTS: Fluorescent leucocytes were clearly visualised in the retinal arteries, capillaries, and veins which allowed measurement of blood flow. The mean capillary velocity was 0.69 (SD 0.21) mm/s. The mean velocities of leucocytes measured in different sized vessels were as follows: 5.83 (2.42) mm/s in arteries over 50 microns, 3.33 (0.62) mm/s in those 35-50 microns, and 2.42 (1.08) mm/s in arteries under 35 microns, 3.08 (1.56) mm/s in veins over 50 microns, 2.79 (1.49) mm/s in those 35-50 microns, and 1.21 (0.50) mm/s in veins under 35 microns. Blood flow pulsation occurs in arteries, arterioles, veins, and venules but not capillaries. CONCLUSION: Fluorescein leucocyte angiography can be used for simultaneous measurement of the blood flow in retinal arteries, veins, and capillaries.

Animals↗
PubMed1999

Reproducibility of fundus autofluorescence measurements obtained using a confocal scanning laser ophthalmoscope.

AIM: To evaluate the reproducibility of the background fundus autofluorescence measurements obtained using a confocal scanning laser ophthalmoscope. METHODS: 10 normal volunteers and 10 patients with retinal disease were included in the study. One eye per subject was chosen randomly. Five images of the same eye of each individual were obtained, after pupillary dilatation, by two investigators using a confocal scanning laser ophthalmoscope. Background fundus autofluorescence was measured at 7 degrees temporal to the fovea in normal volunteers and between 7 and 15 degrees temporal to the fovea in patients. Within session reproducibility of the measurements obtained by each investigator and interobserver reproducibility were evaluated. RESULTS: For investigator 1 the median values of fundus autofluorescence obtained were 31.9 units for normal volunteers and 27.3 units for patients. The median largest differences in readings in normal volunteers was 5.7 units (range 1.4-13.5 units) and in patients 4.2 units (1.5-15.1 units). For investigator 2 the median values of fundus autofluorescence obtained were 28.9 units for normal volunteers and 27.4 units for patients. The median largest difference in readings in normal volunteers was 3.6 units (2.7-11.7 units), and in patients 4.1 units (1.5-9.3 units). The median interobserver difference in readings in normal volunteers was 3.3 units and for patients 6.6 units. The median greatest interobserver difference in measurements obtained for normal volunteers was 8.8 units (8.4-23.0 units) and for patients 11.1 units (7.1-40.8 units). CONCLUSION: Within session reproducibility of the measurements of background fundus autofluorescence was satisfactory. Although interobserver reproducibility was moderate, the variability of the measurements of fundus autofluorescence between observers appears to be small when compared with variation in fundus autofluorescence with age and disease.

Adolescent↗
PubMed1999

Wide-angle fluorescein angiographic scanning with high resolution using a scanning laser ophthalmoscope through a mirror image fixation target.

Internal and moving targets of scanning laser ophthalmoscopes are not capable of observing the fundus beyond a field of more than 80 degrees with high resolution. The authors enabled wide-angle fundus examination with high resolution through a modification of the target. Mirror image fixation targets(MIFT), which fixated the opposite side of the examined eye onto the mirror image of five lamps placed 1.5 m away from the patient, were used to observe the fundus during fluorescein angiography in five diabetic retinopathy patients. In three of them, the ranges of the fundus examinations were measured using conventional internal fixation targets. The mean ranges of the fundus examinations when using MIFT (77.2 +/- 2.5 degrees horizontally, 67.9 +/- 2.1 degrees vertically) were significantly wider than when using internal fixation targets (65.5 +/- 2.6 degrees horizontally, 44.4 +/- 2.8 degrees vertically). MIFT provided a wide angle fundus view with high resolution equal to that of 40 degrees angle images using a scanning laser ophthalmoscope.

Diabetic Retinopathy↗
PubMed2001

[Scotopic threshold response in noninsulin-dependent diabetes mellitus patients with good HbA1c level and ophthalmoscopically intact fundus].

PURPOSE: To evaluate behavior of the scotopic threshold response(STR) and the oscillatory potentials(OPs) of the electroretinogram in noninsulin-dependent diabetes mellitus(NIDDM) patients without retinal abnormalities. METHODS: The STR and the OP 1-3 were recorded from 15 eyes of 15 NIDDM patients aged from 45 to 63 years old with good HbA1c level and ophthalmoscopically intact fundus. As a control group, 8 eyes of 8 age-matched normal subjects were used. The amplitude and the implicit time of the STR as well as the amplitudes and the peak latencies of OP 1-3 were measured. RESULTS: The mean amplitude and the mean implicit time of the STR in the NIDDM group did not differ significantly from those in the control group. The mean amplitudes and the mean peak latencies of the OP 1-3 also showed no significant differences between the NIDDM and control groups. CONCLUSIONS: The STR in NIDDM patients remains normal with good HbA1c level and ophthalmoscopically intact fundus.

Diabetes Mellitus, Type 2↗
PubMedDate not supplied

Improvements after sheathotomy for branch retinal vein occlusion documented by optical coherence tomography and scanning laser ophthalmoscope.

A 55-year-old man presented with decreased visual acuity of 20/400 and central foveal thickness of 450 microm as measured using optical coherence tomography due to a superior temporal branch retinal vein occlusion. Adventitial sheathotomy was performed with a 25-gauge sutureless transconjunctival vitrectomy system. At 1 day, 1 month, and 6 months postoperatively, visual acuity improved to 20/80, 20/40, and 20/30 OS, respectively; central foveal thickness decreased to 228, 195, and 161 microm, respectively; and the scanning laser ophthalmoscope microperimetry showed improved retinal sensitivity and fixation pattern with more stable and central fixation at both postoperative visits. This case indicates optical coherence tomography can detect an early positive effect of sheathotomy surgery on macular edema, and scanning laser ophthalmoscope can document associated improvement in fixation stability.

Decompression, Surgical↗
PubMedDate not supplied

A wide-field, high-resolution ophthalmoscopic contact lens.

A new inverted-image ophthalmoscopic contact lens provides 2X laser spot magnification and a 117 degrees degree instantaneous field of view. It has three times the resolution of very wide-field, inverted-image ophthalmoscopic contact lenses to permit effective use of higher slit-lamp magnifications. The lens was designed for transpupillary thermotherapy with large lesions and panretinal photocoagulation with hazy ocular media.

Contact Lenses↗
PubMed1992

Use of scrolled text in a scanning laser ophthalmoscope to assess reading performance at different retinal locations.

A new technique is described for assessing reading performance using a scanning laser ophthalmoscope. Letters of different sizes and contrasts were projected onto specific retinal locations of normal and low vision observers. Successive letters were scrolled in a horizontal direction at different speeds through a 'window'. Throughout the experiments the subjects' fundus and the retinal location of the stimuli could be visualized. With this scanning laser ophthalmoscope text-scrolling computer program the subject does not search for adjacent letters, and because the eye is held relatively stationary the tedious eye movement analysis incurred in other studies is reduced. Five retinal areas were investigated in two normal observers. The percentage of letters correctly identified decreased with eccentricity, increased velocity of the text and reduced text contrast. The reading performance of two patients, one with age-related macular degeneration and the other with juvenile macular disease, was investigated. Decrements in performance were related to morphology of the lesions.

Adult↗