Assessment of Night Vision Problems in Patients with Congenital Stationary Night Blindness

Abstract

Congenital Stationary Night Blindness (CSNB) is a retinal disorder caused by a signal transmission defect between photoreceptors and bipolar cells. CSNB can be subdivided in CSNB2 (rod signal transmission reduced) and CSNB1 (rod signal transmission absent). The present study is the first in which night vision problems are assessed in CSNB patients in a systematic way, with the purpose of improving rehabilitation for these patients. We assessed the night vision problems of 13 CSNB2 patients and 9 CSNB1 patients by means of a questionnaire on low luminance situations. We furthermore investigated their dark adapted visual functions by the Goldmann Weekers dark adaptation curve, a dark adapted static visual field, and a two-dimensional version of the “Light Lab”. In the latter test, a digital image of a living room with objects was projected on a screen. While increasing the luminance of the image, we asked the patients to report on detection and recognition of objects. The questionnaire showed that the CSNB2 patients hardly experienced any night vision problems, while all CSNB1 patients experienced some problems although they generally did not describe them as severe. The three scotopic tests showed minimally to moderately decreased dark adapted visual functions in the CSNB2 patients, with differences between patients. In contrast, the dark adapted visual functions of the CSNB1 patients were more severely affected, but showed almost no differences between patients. The results from the “2D Light Lab” showed that all CSNB1 patients were blind at low intensities (equal to starlight), but quickly regained vision at higher intensities (full moonlight). Just above their dark adapted thresholds both CSNB1 and CSNB2 patients had normal visual fields. From the results we conclude that night vision problems in CSNB, in contrast to what the name suggests, are not conspicuous and generally not disabling.

Pattern Onset ERGs and VEPs Produced by Patterns Arising From Light Increment and Decrement

“…This ERG phenotype localizes dysfunction to the synapse between photoreceptors and depolarizing bipolar cells and is a characteristic of the complete type of congenital stationary night blindness (cCSNB or CSNB1). Patients with CSNB1 often show visual problems in dim light conditions, [3][4][5][6] but the effects of this retinal dysfunction on subsequent neuronal pathways and cortical vision is not well understood at present.…”

Constructing the rod bipolar cell signalplex using animal models of retinal dysfunction.

“…cCSNB patients report difficulty in performing tasks at night such driving, cycling, and maneuvering in dimly lit social settings such as movie theaters and pubs (Bijveld et al, 2013a). Many cCSNB patients report being blind at night and dependent on others in dark circumstances (Bijveld et al, 2013a).…”

“…cCSNB patients report difficulty in performing tasks at night such driving, cycling, and maneuvering in dimly lit social settings such as movie theaters and pubs (Bijveld et al, 2013a). Many cCSNB patients report being blind at night and dependent on others in dark circumstances (Bijveld et al, 2013a). iCSNB patients report to having difficulty at the aforementioned tasks at a reduced rate and none felt they were always blind at night and dependent on others (Bijveld et al, 2013a).…”

“…Many cCSNB patients report being blind at night and dependent on others in dark circumstances (Bijveld et al, 2013a). iCSNB patients report to having difficulty at the aforementioned tasks at a reduced rate and none felt they were always blind at night and dependent on others (Bijveld et al, 2013a).…”

Clinical Characterization and Frequency of Observation of Hereditary Retinal Diseases: Multicentric Study in Panama in 2012-2013

“…There are cases reported without nictalopia in patients that have never had a normal vision [68], or in Type 2 disease (rod's signal attenuated, but still present) [69]. Hemeralopia as the first symptom also coincides with the diagnosis of Type 2 disease [70].…”