Relative Scotoma Research Articles

Scanning laser ophthalmoscope correlations with biomicroscopic findings and foveal function after macular hole closure.

To investigate the relation between foveal findings and visual function in eyes with a resolved idiopathic macular hole after vitreous surgery. We divided 28 eyes with postoperative idiopathic macular hole resolution into 3 groups based on postoperative biomicroscopic foveal findings of complete closure, partial closure, or atrophic closure. To evaluate foveal retinal function, scanning laser ophthalmoscope (SLO) microperimetry was performed preoperatively and 6 months postoperatively. Postoperatively in 18 eyes (64%), the foveal images became normal or almost normal and were classified as having complete closure, 6 eyes (21%) were classified as having partial closure, and 4 eyes (14%) as having atrophic closure. The corresponding visual acuity levels 6 months postoperatively were, respectively, 0.10, 0.35, and 0.64 (P<.01) based on LogMAR analysis. Preoperative SLO microperimetry detected an absolute scotoma at the bottom of all macular holes; postoperatively, the absolute scotoma disappeared in the 18 eyes with complete hole closure, but a relative scotoma was detected in 6 eyes. Of 6 eyes with partial closure, 1 had an absolute scotoma and 5 had a relative scotoma. An absolute scotoma was detected in 4 eyes with atrophic closure. After macular hole closure, SLO findings correlate both with biomicroscopic findings and foveal function. Better anatomical foveal recovery in eyes after macular hole closure results in better improvement of vision than in eyes in which the foveal anatomical findings are not as good.

White-noise field campimetry in HIV+ patients

The first morphological changes in eyes with HIV infection are microvascular disease of the retina with cotton-wool spots and microaneurysms. The study was performed to find out if evidence of disturbances of ocular microcirculation can be established by non-invasive methods. Twenty-seven patients with HIV infection and without opportunistic infections underwent thorough ophthalmologic examination with threshold-oriented, suprathreshold perimetry (TAP 2000 ct, Oculus) and white-noise field campimetry (TEC, Oculus). Visual field examination was normal in 23 out of 27 patients (85%), whereas 4 patients showed relative field defects in at least one eye. In white-noise field campimetry 13 out of 23 perimetrically unaffected patients (56%) perceived scotomas in one or both eyes. These scotomas were not stable. Three of 4 patients with relative scotomas in the visual field had cotton-wool spots in the retina and showed a stable scotoma in campimetry. Visual acuity, IOP, and cup/disc ratio were within normal ranges. White-noise field campimetry complements the standard examination of patients with HIV and might be capable of indicating disturbances of ocular microcirculation by a non-invasive method before morphological changes in the retina can be seen.

Quantification of functional retinal damage in branch retinal vein thromboses

Branch retinal vein occlusion (BRVO) induces variable functional deficits depending on the grade of vascular occlusion and its localisation. Theses deficiences are not easily defined by visual acuity measurements. However, microperimetry offers topical mapping of retinal function, allowing precise documentation of the intensity and dimension of retinal functional loss in BRVO. Retinal sensitivity was examined using a Rodenstock Scanning Laser Ophthalmoscope (SLO). A standardized grading system of stimuli ranging from 0 to 32 dB was used to document the retinal threshold in three different areas: regions presenting vascular occlusion, the collateral edematous zone and adjacent areas with intact perfusion. Absolute and relative scotomas as well as the fixation behavior were studied. Forty-two patients with isolated BRVO within the vascular arcades were examined with microperimetry and angiography. At initial presentation with BRVO the retinal sensitivity in the area of occlusion on average diminished to 4.1 dB. In the collateral edematous zone retinal threshold was reduced to 21.5 dB; area with intact perfusion demonstrated a threshold of 23.2 dB. Within the occluded area itself defects of significantly differing intensity were found which only partially correlated with the angiographic evidence. Intense scotomas (0 dB) were observed in 59% of the eyes examined: angiographically nonperfused areas or extended intraretinal hemorrhage were present. Relative scotomas (12.1 dB) were seen in 19.1% and minimal, non-significant defects (19.5 dB) were documented in 21.4% of the BRVO. The level of angiographically documented leakage did not correlate with the functional deficits present in these two groups. Measurements performed after 6-8 weeks revealed noticeable spontaneous recovery of retinal sensitivity, unless an additional progressive closure occurred. The average functional improvement in the area of leakage found after laser therapy was less than the results shown in spontaneous resolution of edema. BRVO may lead to significant reductions of central and paracentral retinal function. Angiographically observed leakage is not always directly correlated to the magnitude of retinal sensitivity loss. As spontenous remission is frequent in one group and intact retinal function can be shown in areas of angiographic leakage, therapeutic interventions, e.g., laser treatment, should be carefully considered. Scanning laser ophthalmoscopy provides additional information for precise evaluation and follow-up of the retinal damage in BRVO.

Phosphenes and transient scotomas induced by magnetic stimulation of the occipital lobe: their topographic relationship

Transcranial magnetic stimulation (TMS) of the visual cortex is known to induce phosphenes and is able to suppress visual perception. To address the topographic relationship of phosphenes and transient scotomas, the visual field of 10 normal subjects was investigated using a perimetric approach. The central visual field (diameter: 20°) was tested at 32 sites. Perceptual thresholds were determined by presenting 1 ms test spots flashed with varying intensity in random order. TMS was applied with a focal figure-of-eight coil placed over the inion. All subjects perceived phosphenes, mostly restricted to one of the lower quadrants within the visual field. In 13 out of 15 investigations, a magnetic stimulus triggered 100 ms after the visual target resulted in a relative scotoma with threshold changes of 8 dB or more. In 9 of 13 investigations, scotomas coincided spatially with sketches of phosphenes made by subjects in a separate test. Scotomas covered only a small percentage of the total visual field, which may explain the failure of previous studies to find perceptual suppression with the focal coil. The present result demonstrates that phosphenes evoked during TMS can serve as a guide for optimal visual stimulus alignment in neuropsychological experiments.

THE USE OF DYE DILUTION CURVE ANALYSIS IN THE QUANTIFICATION OF INDOCYANINE GREEN ANGIOGRAMS OF THE HUMAN CHOROID

THE USE OF DYE DILUTION CURVE ANALYSIS IN THE QUANTIFICATION OF INDOCYANINE GREEN ANGIOGRAMS OF THE HUMAN CHOROID

Visual Field Loss in RCS Rats and the Effect of RPE Cell Transplantation

The consequences of progressive retinal degeneration on central visual function were studied by recording single and multiunit receptive fields (RFs) across the surface of the superior colliculus (SC) of pigmented dystrophic RCS rats. Retinal morphology was used to provide a correlation between function and histological appearance. In addition, the potential protective effect of retinal pigment epithelium (RPE) transplantation was studied in a similar manner in dystrophic animals in which RPE cells were injected into the subretinal space, or the vitreous humor, at between 21 and 28 days of age. The visual responsiveness of SC units in dystrophic rats differed markedly from those in nondystrophics. Dystrophic rats developed a relative scotoma beginning in the central visual field by 42–45 days of age and expanding to include 50% of the visual field by 97–107 days. In contrast, following subretinal RPE transplantation, there was photoreceptor rescue correlated with a partial to complete preservation of RF representation when examined at 85 to 108 days of age. The majority of photoreceptor rescue occurred in the region of graft placement with possible low level rescue across the central retina. Dystrophic animals that had received intravitreal RPE transplants showed poor photoreceptor survival as well as minimal functional preservation. Our results indicate that there is a progressive central to peripheral loss of visual responsiveness in the SC of dystrophic RCS rats which can be limited by subretinal injections of healthy RPE cells.

Scanning Laser Ophthalmoscope Fundus Perimetry After Surgery for Choroidal Neovascularization

Purpose: Submacular surgery is under investigation for the treatment of subfoveal choroidal neovascularization secondary to age-related macular degeneration, ocular histoplasmosis syndrome, and other causes. The aims of this study were to determine whether the macular area from which choroidal neovascularization was removed surgically remained functional and whether there was any qualitative difference between eyes with different disease conditions or between eyes of younger and older patients. Methods: Our study included 19 patients (19 eyes) with choroidal neovascularization, seven cases caused by age-related macular degeneration and 12 caused by ocular histoplasmosis syndrome, pathologic myopia, or idiopathic causes. All tests were performed at least 6 months after surgical removal of choroidal neovascularization. All patients underwent fundus perimetry with the scanning laser ophthalmoscope for evaluation of dense and relative scotomas and fixation site. Results: After submacular surgery in 19 patients, 10 patients (one with age-related macular degeneration and nine with pathologic myopia, ocular histoplasmosis syndrome, or an idiopathic cause of choroidal neovascularization) fixated within an area that ophthalmoscopically and angiographically was an area of retinal pigment epithelial disturbance occupied by choroidal neovascularization preoperatively. Of 12 patients without age-related macular degeneration, seven of eight patients younger than 50 years of age compared with two of four patients 50 years or older fixated within the area of retinal pigment epithelial disturbance. Conclusions: Our data suggest that in patients without age-related macular degeneration who undergo submacular surgery, the surgically disturbed area previously occupied by choroidal neovascularization can remain functional postoperatively. Furthermore, occasionally a patient with age-related macular degeneration undergoing submacular surgery still can fixate in the area from which the choroidal neovascularization was removed.

Visual Field Loss After Vitrectomy for Full-thickness Macular Holes

To report the results of a prospective study of the incidence of peripheral visual field loss after macular hole surgery. Prospectively, 30 eyes of 30 consecutive patients with full-thickness macular holes operated on between December 1995 and April 1996 had preoperative and postoperative Goldmann visual field tests. The surgical procedure consisted of three-port pars plana vitrectomy, posterior hyaloid removal, nonexpansile fluid-hexafluoroethane (C2F6) exchange, and, in 19 of 30 patients, autologous platelet injection, followed by face-down positioning. Twenty-nine of these 30 cases were considered to be anatomic successes. Comparison of preoperative and postoperative visual fields disclosed that four patients (13%) had a peripheral scotoma, including one patient with stage 4 macular hole. Three other patients (10%) had a postoperative relative arcuate defect. Mean postoperative intraocular pressure was higher in the latter group. None of the patients complained of peripheral scotoma. Overall, seven of 30 patients (23%) had a postoperative visual field defect. Two categories of scotomas were observed: peripheral and relative arcuate. The cause of peripheral visual field loss is unclear. Increased intraocular pressure may be the cause of relative arcuate scotomas.

Differentiating full thickness macular holes from impending macular holes and macular pseudoholes

AIMSThe reliability of scanning laser ophthalmoscope (SLO) microperimetry in differentiating full thickness macular holes from macular pseudoholes and impending macular holes was evaluated.METHODS106 eyes with the clinical diagnosis of full...

Monocular optokinetic nystagmus in humans with age-related maculopathy

AIMTo investigate full field monocular optokinetic nystagmus (OKN) in patients with age-related maculopathy (ARM) and relative central scotoma.METHODSSix patients aged 59–88 years with bilateral ARM and an aged-matched control group...

Assessment of visual function in choroidal neovascularization with scanning laser microperimetry and simultaneous indocyanine green angiography.

Clinical management and treatment of diseases with choroidal neovascularization (CNV) are mainly based on visual acuity, which may give an incomplete picture of the associated visual dysfunctions. With the advent of new experimental treatment modalities such as alfa-interferon, radiation, or surgical excision of CNV, it is increasingly important to develop better methods for characterizing the associated visual function. Microperimetry with the scanning laser ophthalmoscope (SLO) allows precise point-to-point correlation between visual function and the macular pathology. However, precise delineation of CNV is a prerequisite for accurate correlation of the functional results with the CNV. A total of 40 eyes with CNV secondary to age-related macular degeneration were evaluated with static manual microperimetry using the SLO to quantitate relative and absolute scotomata within the CNV. For precise delineation of the CNV, indocyanine green (ICG) angiography was simultaneously performed, allowing stimulus presentation at any desired retinal location under visual feedback of the angiogram. A relative scotoma was detected in 19 and an absolute scotoma in 21 out of 40 eyes. The depth of the scotomata was correlated with the duration of symptoms (P < 0.01). Eyes with well-defined CNV had significantly deeper scotomas than eyes with occult CNV (P < 0.005). Microperimetry using the SLO and simultaneous ICG angiography demonstrated relative and absolute scotoma within the CNV. The depth of the scotoma may guide the ophthalmologist in selecting the adequate treatment.

Automated perimetry in patients with choroidal metastases.

Recent work using computerised perimetry has documented predictable visual field defects in patients with choroidal melanoma. Despite the higher frequency of occurrence of choroidal metastases, relatively little is known about their exact effects on visual performance, specifically with respect to visual field. This study is a pilot retrospective analysis of the results of automated perimetry testing in patients with choroidal metastatic disease. The Humphrey field analyser was used to perform visual field tests on 15 eyes in 11 patients diagnosed with choroidal metastases. All 11 primary tumours were carcinomas originating in the breast (seven), lung (one), kidney (one), stomach (one), and prostate (one). All patients had either central 30 and/or peripheral 30-60 threshold strategies. Each of the 15 eyes tested had a demonstrable visual field defect. Eight eyes (53%) had absolute scotomas and seven (43%) had relative scotomas; the defects did not consistently correspond in size or location to the tumour as depicted by ophthalmoscopy or ultrasonography. This is in contradistinction to automated perimetry results in patients with choroidal melanoma. Three of the four eyes (75%) which were retested after treatment of the metastases showed improvement of the visual field. Seven of nine eyes (77%) that initially had reduced visual acuity had improvement after treatment. This clinical improvement corresponded well to tumour shrinkage and resolution of subretinal fluid. These findings may be useful in the decision to initiate treatment for symptomatic choroidal metastatic disease and in explaining to patients and their referring physicians what improvement could be expected from such treatment. A prospective evaluation of patients with choroidal metastases seems appropriate based on this pilot experience and may elucidate if the differences noted between visual field performance of these patients and those with choroidal melanoma may be useful in some diagnostically difficult cases.

Visual field defects due to spectacle frames: their prediction and relationship to UK driving standards

One male and one female subject wore a selection of ten current spectacle frames in random order. Monocular visual fields were assessed using an Aimark perimeter in accordance with UK Driver and Vehicle Licensing Authority (DVLA) guidelines. Of the ten frames, seven plastic frames produced an absolute scotoma intruding into a 120 ° × 40 ° ‘letterbox’ area acting as a driving visual field template. Three metal frames gave a relative scotoma; however, our apparatus was too insensitive to plot these scotomata. Relevant frame and patient parameters were measured and entered into a computer program which enabled theoretical visual field defects due to a spectacle frame to be calculated. Good agreement is shown to be possible between actual and computed visual field defects. Spectacle frames can and frequently do cause visual field defects which may affect a driver's fitness to drive. Our data also show that a frame which allows an adequate field of vision at night could cause a marked visual field defect during daylight hours. A model and rule-of-thumb are given to determine the size of these potential defects and suggestions are given to minimise or eliminate them.

Visual field defects due to spectacle frames: their prediction and relationship to UK driving standards

SummaryOne male and one female subject wore a selection of ten current spectacle frames in random order. Monocular visual fields were assessed using an Aimark perimeter in accordance with UK Driver and Vehicle Licensing Authority (DVLA) guidelines. Of the ten frames, seven plastic frames produced an absolute scotoma intruding into a 120°× 40°‘letterbox’ area acting as a driving visual field template. Three metal frames gave a relative scotoma; however, our apparatus was too insensitive to plot these scotomata. Relevant frame and patient parameters were measured and entered into a computer program which enabled theoretical visual field defects due to a spectacle frame to be calculated. Good agreement is shown to be possible between actual and computed visual field defects. Spectacle frames can and frequently do cause visual field defects which may affect a driver's fitness to drive. Our data also show that a frame which allows an adequate field of vision at night could cause a marked visual field defect during daylight hours. A model and rule‐of‐thumb are given to determine the size of these potential defects and suggestions are given to minimise or eliminate them.

Intraocular motility, electrophysiological tests and visual fields in drug addicts

SummaryThe effects of drugs on intraocular motility, retina function and central pathways in a drug addicts population have been studied. The study group were made up of 15 drug addicts. Fifteen healthy subjects who had never used drugs acted as a control group. Refractive state, accommodation, tonometry, assessment of pupillary reflexes, campimetry, visual evoked cortical potential (VECP) and ERG were performed in all cases. All the subjects studied used heroine, 12 used cannabis and 12 used cocaine. Refraction was normal in all cases. Accommodation amplitude in normal subjects ranged from 8.5 to 11.5 D, and from 3.5 to 9.5 D in the drug addicts group. Tonometry indicated a tendency to lower intraocular pressure values. Direct and consensual pupillary reflexes were normal in eight subjects, but were sluggish in the rest. Campimetry showed relative and absolute scotoma in five subjects. VECP were found to be normal in two of the cases, moderately pathological in six and pathological in the remaining seven cases. As for the ERG, it showed non‐specific altered traces in 11 cases. Accommodation amplitude was lower than normal in 20 eyes. The decrease of VECP with altered traces but with an increase of latency, seem to indicate the presence of an alteration in the optical pathway or in the cortical centres. The findings in ERG point out a decrease of amplitudes and an increase of latency in more than half the population studied.

Intraocular motility, electrophysiological tests and visual fields in drug addicts

The effects of drugs on intraocular motility, retina function and central pathways in a drug addicts population have been studied. The study group were made up of 15 drug addicts. Fifteen healthy subjects who had never used drugs acted as a control group. Refractive state, accommodation, tonometry, assessment of pupillary reflexes, campimetry, visual evoked cortical potential (VECP) and ERG were performed in all cases. All the subjects studied used heroine, 12 used cannabis and 12 used cocaine. Refraction was normal in all cases. Accommodation amplitude in normal subjects ranged from 8.5 to 11.5 D, and from 3.5 to 9.5 D in the drug addicts group. Tonometry indicated a tendency to lower intraocular pressure values. Direct and consensual pupillary reflexes were normal in eight subjects, but were sluggish in the rest. Campimetry showed relative and absolute scotoma in five subjects. VECP were found to be normal in two of the cases, moderately pathological in six and pathological in the remaining seven cases. As for the ERG, it showed non-specific altered traces in 11 cases. Accommodation amplitude was lower than normal in 20 eyes. The decrease of VECP with altered traces but with an increase of latency, seem to indicate the presence of an alteration in the optical pathway or in the cortical centres. The findings in ERG point out a decrease of amplitudes and an increase of latency in more than half the population studied.

Relation of the functional and structural fundus changes after submacular surgery for neovascular age-related macular degeneration.

This study was carried out to investigate the precise pattern of visual loss associated with subfoveal choroidal neovascular membranes and the mechanism by which vision is stabilised or improved after submacular surgery. Preoperative and postoperative quantitative microperimetry using the scanning laser ophthalmoscope was performed on six eyes of five patients with age-related macular degeneration who underwent subfoveal choroidal neovascular membrane excision. The relation of the microperimetry findings to the preoperative and postoperative fluorescein angiographic features was also assessed. Four of the six eyes had visual improvement by the 6 month postoperative visit; the other two had stabilisation of vision at the preoperative level. Despite these beneficial visual effects, none of the patients fixated within the bed of the excised choroidal neovascular membrane. Subfoveal choroidal membrane excision was associated with a 36% average increase in the absolute scotoma at the 1 month postoperative visit, compared with the preoperative size. The postoperative scotoma appeared to remain stable or decreased slightly in size between the 6 month and 1 year postoperative visits. Recovery of vision was associated with the development of a more stable preferred eccentric fixation locus, of which the distance from the centre of the foveal avascular zone was related to final postoperative vision. Most of the eccentric fixation loci were inferotemporal to the bed of the excised choroidal neovascular membrane. The surgical retinotomy site was associated with persistent postoperative relative scotoma in five of the six cases, but resolved in one patient after 1 year. These findings indicate that quantitative scanning laser ophthalmoscope microperimetry may aid in the surgical planning of subfoveal choroidal neovascular membrane excision.

Ophthalmologic Features of Thallium Poisoning

Thallium intoxication is characterized by the development of painful peripheral neuropathy, alopecia, mental disorders, and in severe cases, respiratory failure and death. Toxic optic neuropathy is also a feature. Ophthalmologic features of thallium poisoning include optic neuropathy, blepharoptosis, lens opacities, and ophthalmoplegia. A 44-year-old man with criminal sublethal thallium poisoning was examined one month after he was seen in the neurology department with classic systemic features. He was found to have diminished contrast sensitivity, a tritan defect in color vision, and a relative cecocentral scotoma before he developed optic atrophy.

3-dimensional topography of the optic papilla with laser scanning tomography: clinical correlation of cluster analysis

BACKGROUND The evaluation of optic disc topography is essential for the clinical diagnosis of primary open angle glaucoma. The purpose of this study was (1) to establish a computerized cluster formation of optic nerve head topography based on quantitative three-dimensional parameter values and (2) to describe the resulting clusters according to morphological appearance and visual fields. PATIENTS AND METHODS 337 optic nerve heads (glaucomatous optic neuropathy (n = 99), glaucoma suspects (n = 159), normals (n = 79) were analyzed using laser scanning tomography. A hierarchical cluster analysis was performed based on standardized variables (optic disc area, rim area, area-ratio, cup depth, cup steepness, height variations along the contour-line). Visual fields were tested by computerized static threshold perimetry. RESULTS A seven cluster solution met the optimizing criteria. The characteristic morphology of the clusters can be described as "normal" (N), "normal, large" (NL), "supernormal" (SN), "pseudonormal" (PN), "glaucoma-like-flat" (GF), "glaucoma-like-steep" (GS) and "macropapillary" (M). Visual fields were normal in 180 eyes. 99 eyes had glaucomatous field defects, 58 eyes revealed isolated relative scotomas < 10 db. Presence and degree of visual field defects varied within the automatically classified optic disc groups considerably. Visual field defects were found in 7.7% (SN), 8.3% (N), 18.8% (NL), 33.3% (M), 37% (PN), 64.7% (GF) and 83.3% (GS) respectively. Pseudonormal discs were characterized by a flattening of the height variations along the disc border. CONCLUSIONS (1) Optic nerve heads may be automatically classified based upon a combination of three-dimensional topographic variables. (2) Analysis of optic disc topography and computerized perimetry are supplementary tools in the evaluation of the glaucoma patient. Visual field defects may be present within any cluster. However, the likelyness of the presence of visual field defects differs considerably among the topometrically defined groups of optic nerve heads. Functional damage is to be expected in association with reduced height variations along the disc border, a small rim area and a steep cupping of the optic nerve head.

Ophthalmologic Features of Thallium Poisoning

Thallium intoxication is characterized by the development of painful peripheral neuropathy, alopecia, mental disorders, and in severe cases, respiratory failure and death. Toxic optic neuropathy is also a feature. Ophthalmologic features of thallium poisoning include optic neuropathy, blepharoptosis, lens opacities, and ophthalmoplegia. A 44-year-old man with criminal sublethal thallium poisoning was examined one month after he was seen in the neurology department with classic systemic features. He was found to have diminished contrast sensitivity, a tritan defect in color vision, and a relative cecocentral scotoma before he developed optic atrophy.