Search

The scanning laser ophthalmoscope (SLO) is an instrument of great value for observing viewing behaviour and characteristics of fixation in macula disorders; it also may have potential in assessing visual rehabilitation in affected individuals. It is important to understand the viewing strategies used by individuals with a central scotoma and eccentric fixation and to determine whether these strategies have changed as a result of any eccentric viewing training. We describe a method based on searching for multiple sectors in relative correspondence in consecutive SLO fundus images. In this method, successive fixation positions, and consequently viewing strategy, during the reading of isolated words and text passages can be extracted from SLO images. We found the maximum cumulative error in determining fixation position over 1000 consecutive frames to be 5 pixels (approximately 15 min arc) using fundus images from an individual with a macular lesion and clearly visible retinal features. The reconstruction of...

The authors examined a 45-year-old-woman complaining of a dull pain located in the left retro-orbital area, which had started six months previously. She also reported a progressive blurring of vision in the left eye that had developed over the last two months. She had a history of chronic sinusitis beginning in her twenties. Two years prior to the examinaton she had sustained a minor head injury. Skull X-rays performed at that time showed a mass lesion in the sphenoid sinus, which however was overlooked. The authors found that visual acuity was 20/20 in both eyes and that, with Goldmann kinetic perimetry, the blind spot was enlarged and isopters were moderately constricted in the left eye. CT scan and MRI showed a large homogeneous non-enhancing lesion within the left sphenoid sinus, compressing the left optic nerve. At surgery, an encapsulated cyst was found containing a yellowish material. Histological examination led to a diagnosis of cholesteatoma. To the authors′ knowledge, this is the first descript...

Characteristic features of the size and location of the blind spot were analyzed by computerized perimetry. A new strategy devised for relatively fast and precise measurement of the blind spot was used, with an Octopus 2000R perimeter.In a first series of 30 normal subjects, height and width, average of height and width, square root of the product of height and width, and horizontal and vertical coordinates of the center were computed. In a second series consisting of 49 normal subjects, repeatability of the measures was evaluated. The influence of the stimulus intensity was evaluated.Height of the blind spot exceeded its width. However, the correlation between width and height values was weak. This suggested that, even in normal subjects, assessing the width of the blind spot did not provide a substantial indication of its height. Decreasing stimulus intensity was associated with increase in width and height. In addition, a temporal shift of the mean horizontal coordinates of the center was demonstrated ...

A variety of disorders involving the retina or the visual pathways are associated with enlargement of the blind spot, and, when using manual perimetry, determination of the blind spot is a routine procedure. Yet, using automated static perimetry, evaluation of the blind spot is hardly ever performed, because, with routine strategies, restriction in the number of tested locations results in poor delineation of small scotomata. Currently available computer programs designed for a precise evaluation of the blind spot necessitate the testing of a large number of locations. The authors have developed a spatially adaptive strategy for relatively fast and precise measurement of the blind spot using automated perimetry. It determines the width and height of the blind spot, taking into account interocular variability in location of the scotoma. Using this procedure, computerized static evaluation of the blind spot requires a mean of 38.9 tested locations, and as a result is much shorter than with other comparable ...

The use of automated perimetry in retinitis pigmentosa (RP) has not become widespread. This is due to what is considered as a relative lack of automated programs designed to evaluate in the entire visual field both discrete abnormalities and pronounced defects, using a reasonably short procedure.Three patients suffering from different forms of retinitis pigmentosa were evaluated by means of the new Octopus program N1. In two patients, visual fields were also evaluated by Goldmann kinetic perimetry. Automated perimetry demonstrated the characteristic pattern of the visual field defects of retinitis pigmentosa as satisfactorily as Goldmann perimetry. Moreover, it provided better analysis of the central visual field, revealing partially preserved areas which were missed by routine kinetic perimetry.Evaluation with the Octopus program N1 required much less time than with regular 4-2-2 programs for automated perimetry, because of a unique combination of screening and quantified strategies. The collected data a...

We examined a patient with a severe vasospastic condition, who complained of severe pain and transient obscurations in the right eye when exposed to bright light for five to ten minutes, It is probable that, in susceptible patients, exposure to bright light induces vasospasm in branches of the ophthalmic artery, leading to pain and monocular visual changes.