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Y. Liu, X.Z. Gu; The observations of vertical OKN in 27 normal subjects . Invest. Ophthalmol. Vis. Sci. 2004;45(13):2531.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: to explore the characteristics and to analyze the clinical values of vertical Optokinetic nystagmus(OKN) in normal subjects. Methods: Full–field vertical OKN were recorded in 54 eyes of 27 healthy adult subjects (age range, 18–32 years) using VTS–III visual vestibular function test apparatus. Each eye was given three groups of optokinetic (OK) stimulations separately at intervals of ten minutes, which were black–and–white stripes with a fixed spatial frequency moving upward and downward at the uniform speeds of 30 and 60 deg/s as well as stripes of sinusoidal movement with a peak speed of 60 deg/s and a frequency of 0.05Hz. The data were analyzed by a specified software to get all parameter values, which then were processed with SPSS software package. Results: the gain values for downward and upward movements of OKN at 300/s are 0.99±0.29 and 0.97±0.29 respectively, there is no statistic difference between these two results; the slow phase velocity dissymmetry percentage (SPVDP) is 12.49±10.84%. When the stimulating speed was increased to 600/s , the gain values for downward and upward movement decreased obviously , being 0.57±0.21 and 0.47±0.21 respectively; Moreover, when we compared the gain of downward movement with that of upward movement , these two data also showed a statistical difference. The SPVDP is 17.56 ±13.71%. As for sinusoidal OKN, the gain values of downward and upward movement were 0.57±0.21 and 0.47±0.21 respectively, there was no significant difference between these two data. Conclusions:The function of vertical optokinetic stimulus is an important factor to affect the vestibular function response, it is useful in the formation of spatial perception, the occurrence of motion sickness and clinical assessments of optokinetic system and vestibular function. By the examinations of induced vertical OKN, we could know more information about the function of patients’eye movements. The vertical OKN assist diagnosis and different diagnosis. Also we could use this eye movement test as a tool to monitor the results of clinical treatment.
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