Congenital stationary night blindness and a "Schubert-Bornschein" type electrophysiology in a family with dominant inheritance

Abstract

Background/aims: To present the clinical, psychophysical, and electrophysiological characteristics of a family with dominantly inherited congenital stationary night blindness (CSNB). Methods: Five affected family members from three generations were ascertained. Four affected individuals underwent ophthalmic examination and electrodiagnostic investigations. Three affected individuals also underwent scanning laser ophthalmoscopy and psychophysical testing. Results: Affected individuals reported night blindness from an early age. Visual acuities were normal. Fundal appearances were normal apart from one older patient showing areas of peripheral chorioretinal atrophy. Autofluorescence images showed no gross abnormality. International Society for Clinical Electrophysiology of Vision (ISCEV) standard electroretinography (ERG) showed undetectable rod specific responses and electronegative maximal responses, but normal ISCEV cone responses. Additional S-cone specific ERG recordings were of reduced amplitude in all patients studied. There was no apparent rod component to the dark adaptation curve. Central 30˚thresholds were normal under photopic conditions but showed increased thresholds under scotopic conditons for both red and blue stimuli. Conclusion: Results from investigation of this family are consistent with an impairment of rod photoreceptor signalling. The ERG findings suggest an abnormality occurring after phototransduction with rod and S-cone pathway involvement. These findings differ from those rare families reported previously with dominant CSNB.

Autofluorescence Imaging and Spectral-Domain Optical Coherence Tomography in Incomplete Congenital Stationary Night Blindness and Comparison With Retinitis Pigmentosa

“…These results were similarly unremarkable, although the oldest patient (58 years of age) did exhibit some small atrophic areas around the central macula as well as larger areas of atrophy in the periphery. 27 In light of the other 2 patients in the above study as well as all 5 of our patients having demonstrated normal FAF appearances, we believe that these abnormal features were likely unrelated to CSNB.…”

Clinical and electroretinographic characteristics of congenital stationary night blindness in the Appaloosa and the association with the leopard complex

“…However, the changes in the photopic b‐wave and those described in the cone flicker are believed to provide evidence for the existence of postsynaptic abnormalities in the cone pathway 27 . Post‐transductional dysfunction of cone pathways is also supported by investigations of the on and off responses in different forms of human SB‐CSNB 28 . Changes in the photopic b‐wave of the CSNB‐affected horses may support the existence of postsynaptic cone pathway abnormalities.…”

ON- and OFF-response of the photopic electroretinogram in relation to stimulus characteristics

“…Wavelengths of the chromatic LED stimuli were 3 cd s/m 2 10 cd/m 2 200 and 250 Red and green flash on white background [10] 750 cd/m 2 42 cd/m 2 500 White flash on white background [11] 3 cd s/m 2 10 cd/m 2 256 630 nm flash on white background [12] 440 cd/m 2 160 cd/m 2 200 612 nm flash on 530 nm background [13] 3 log cd s/m 2 2 log cd/m 2 200 White flash on white background [15] 398 cd/m 2 48 cd/m 2 200 White flash on white background [16] 3.4 log phot td 3.7 log scot td 200 630 nm flash on 450 nm background [17] 0.6-3.5 log cd/m 2 40 cd/m 2 250 White flash on white background calibrated with the USB2000 Fibre Optic Spectrometer (Ocean Optics Inc., Dunedin, USA). The amplitude of a-wave was measured from stimulus onset to the first negative trough.…”

“…ON-and OFF-responses have been studied in various retinal dystrophies [1,2,[9][10][11][12][13][14][15] where they might be important indicators of inner retinal dysfunction, not necessarily recognized by the conventional cone ERG. Although several electrophysiological laboratories use long duration flash ERG (Table 1), stimulus parameters have not been standardised yet.…”