ABSTRACT
Purpose: Enhanced S-cone syndrome (ESCS), a rare disorder, is often misdiagnosed as other forms of retinal degenerations, which have a poorer prognosis than ESCS. The aim of this study is to report the varied clinical features of ESCS and distinguish it from other similar disorders. Methods: We retrospectively scrutinized the records of patients with confirmed diagnosis of ESCS and analyzed the findings. Results: We included 14 patients (age range 4–39 years) who were confirmed to have ESCS according to pathognomonic electroretinography (ERG) showing reduced photopic, combined responses, and 30 Hz flicker with reduced L, M cone responses and supernormal S cone responses. The disease presented in the 1st decade with night blindness and was almost stationary or minimally progressive. Mid-peripheral fundus changes in form of nummular pigmentary alterations, yellow punctate lesions, and macular schisis were noted. The vision ranged from 6/6 to 6/36 with follow-up ranging from 1month to 22 years. Conclusion: ESCS shows varied clinical features ranging from unremarkable fundus to pigment clumping and atrophic lesions. It has good prognosis with patients mostly maintaining their vision. ERG is diagnostic. More awareness and knowledge about this entity can help to differentiate it from other forms of night blindness.
ABSTRACT
BackgroundOscillatory potentials (OPs) has been used extensively in experimental research and clinical diagnosis,but it is well known that OPs are the summating potentials originated from retinal rod and cone.To separate the rod and cone OPs is helpful for us to diagnose some retinal diseases.ObjectiveThis study was to analyze the characteristics of cone-and rod-driven OPs. Methods The retinal cone degeneration ( RCD ) and congenital stationary night blindness(CSNB) rats were used in this study and SD rats served as control,and 6 rats for each kinds of animals.Scotopic and photopic OPs were recorded in each rat under the dark adaptation for 12 hours and light adaptation for 10 minutes at the stimulate light intensities of -35,-25,-15,-5,0,5 db respectively with RETIscan Visual Electrophysical System.The scotopic and photopic OPs were extracted from flash electroretinogram (FERG) with Maflab7.0 Butterworth filtering waves,and the frequency spectrum of the OPs was analyzed by fast Fourier transform.The characteristics of OPs from RCD rats and CSNB rats were assessed and compared.Results The a wave and b wave of ERG were showed under the dark adaptation condition in both SD and RCD rats,but the b wave was absent in CSNB rat.Under the light adaptation condition,b wave was seen in both SD and CSNB rats,but a wave and b wave of RCD rat were absent.Two peaks were exhibited in both SD and RCD rats under the darkadaptation condition and high intensity of stimulate light at the lower frequency( domain frequency) of 75-110 Hz,90-120 Hz and high frequency ( minor frequency) 90- 120 Hz,110- 135 Hz respectively.In various intensities of stimulate light,CSNB rats appeared a peak at 70-100 Hz.But in light-adaptation and various intensities of stimulate light,the frequency peaks were seen at 75-95 Hz and 70-85 Hz from both SD and CSNB rats respectively.However,under the light adaptation condition,only one peak was seen in SD and CSNB rats at the 75-95 Hz and 70-85 Hz respectively.Compared with SD rats,the mean implied time of b wave was delayed and the amplitude was lowed under the light adaptation (P＜0.05 ),however,no significant differences were found in the implied time and amplitude of b wave of scotopic ERG between SD rats and RCD rats( P＞0.05 ).The scotopic OPs showed the prolong implied time and depressed amplitudes in RCD rats and CSNB rats compared with SD rats( P＜0.05 ),and the photopic OPs presented the prolong implied time and lowed amplitude in CSNB rat in comparison with SD rats (P ＜ O.05 ).ConclusionsCone- and rod-driven OPs appear very different characteristics.The results of this study imply that rod pathway gives more contribution to OPs than cone pathway.Analysis of these results will be helpful for the exploration of the origin of OPs and the diagnosis of the related disease.
ABSTRACT
PURPOSE: To report a case of Congenital stationary night blindness associated with myopia. METHODS: A 19-year-old male with night blindness was referred to our hospital. We studied patient's family history, refraction, color vision test, fundus examination, electroretinogram and visual field. RESULTS: Both fundi showed temporal conus and myopic change. Both visual field revealed generalized depression. The light- and dark-adapted electroretinogram showed a normal a wave with extremely reduced b wave, resulting in a typical "negative" wave form.