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Assessment of night vision problems in patients with congenital stationary night blindness.

Bijveld MM, van Genderen MM, Hoeben FP, Katzin AA, van Nispen RM, Riemslag FC, Kappers AM - PLoS ONE (2013)

Bottom Line: 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 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).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.

View Article: PubMed Central - PubMed

Affiliation: Bartiméus Institute for the Visually Impaired, Zeist, The Netherlands. mbijveld@bartimeus.nl

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.

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Dark adaptation curves of the CSNB2 patients (A) and CSNB1 patients (B), and a control subject (green curve).The normal DA curve shows a biphasic form, with an early cone-mediated phase and a later rod-mediated phase. The DA curves of the CSNB2 patients also showed such a biphasic form. Their final thresholds were variably elevated. The DA curves of the CSNB1 patients only showed a cone-mediated phase. Their final thresholds were all approximately 3 log units elevated.
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pone-0062927-g004: Dark adaptation curves of the CSNB2 patients (A) and CSNB1 patients (B), and a control subject (green curve).The normal DA curve shows a biphasic form, with an early cone-mediated phase and a later rod-mediated phase. The DA curves of the CSNB2 patients also showed such a biphasic form. Their final thresholds were variably elevated. The DA curves of the CSNB1 patients only showed a cone-mediated phase. Their final thresholds were all approximately 3 log units elevated.

Mentions: In normal subjects, the DA curve shows a biphasic form, with an early cone-mediated phase during the first 5 min and a later rod-mediated phase (Fig. 4, green solid curve). The dark adaptation curves of the CSNB2 patients also show such a biphasic form but the final threshold was elevated, see Fig. 4. The threshold after 5 min varied between 4.0 and 5.5 log units, a range of 1.5 log units, and after 25 min between 2.2 and 3.7 log units, a range of 1.5 log units. In contrast, in the CSNB1 patients the variation in the threshold was large at the beginning of the dark adaptation curve, but decreased as the dark adaptation continued. The threshold after 5 min varied between 4.8 and 5.8 log units, a range of 1 log unit, but the final threshold after 20 min was found between 4.55 and 4.8 log units, a range of only 0.25 log units. Compared to the final threshold of 1.8 log units in a control subject, the final threshold elevation was between 0.4 and 1.9 log units in the CSNB2 patients and about 3 log units in the CSNB1 patients.


Assessment of night vision problems in patients with congenital stationary night blindness.

Bijveld MM, van Genderen MM, Hoeben FP, Katzin AA, van Nispen RM, Riemslag FC, Kappers AM - PLoS ONE (2013)

Dark adaptation curves of the CSNB2 patients (A) and CSNB1 patients (B), and a control subject (green curve).The normal DA curve shows a biphasic form, with an early cone-mediated phase and a later rod-mediated phase. The DA curves of the CSNB2 patients also showed such a biphasic form. Their final thresholds were variably elevated. The DA curves of the CSNB1 patients only showed a cone-mediated phase. Their final thresholds were all approximately 3 log units elevated.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3643903&req=5

pone-0062927-g004: Dark adaptation curves of the CSNB2 patients (A) and CSNB1 patients (B), and a control subject (green curve).The normal DA curve shows a biphasic form, with an early cone-mediated phase and a later rod-mediated phase. The DA curves of the CSNB2 patients also showed such a biphasic form. Their final thresholds were variably elevated. The DA curves of the CSNB1 patients only showed a cone-mediated phase. Their final thresholds were all approximately 3 log units elevated.
Mentions: In normal subjects, the DA curve shows a biphasic form, with an early cone-mediated phase during the first 5 min and a later rod-mediated phase (Fig. 4, green solid curve). The dark adaptation curves of the CSNB2 patients also show such a biphasic form but the final threshold was elevated, see Fig. 4. The threshold after 5 min varied between 4.0 and 5.5 log units, a range of 1.5 log units, and after 25 min between 2.2 and 3.7 log units, a range of 1.5 log units. In contrast, in the CSNB1 patients the variation in the threshold was large at the beginning of the dark adaptation curve, but decreased as the dark adaptation continued. The threshold after 5 min varied between 4.8 and 5.8 log units, a range of 1 log unit, but the final threshold after 20 min was found between 4.55 and 4.8 log units, a range of only 0.25 log units. Compared to the final threshold of 1.8 log units in a control subject, the final threshold elevation was between 0.4 and 1.9 log units in the CSNB2 patients and about 3 log units in the CSNB1 patients.

Bottom Line: 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 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).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.

View Article: PubMed Central - PubMed

Affiliation: Bartiméus Institute for the Visually Impaired, Zeist, The Netherlands. mbijveld@bartimeus.nl

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.

Show MeSH
Related in: MedlinePlus