ABSTRACT
Objective@#To evaluate the repeatability of corneal biomechanics parameters measured by Corneal Visualization Scheimpflug Technology (Corvis ST) and explore the factors that influence the repeatability.@*Methods@#A diagnostic test study was performed.A total of 190 eyes in 95 myopia patients (34 males and 61 females) were enrolled from September to October 2017 in Henan Eye Hospital.All the subjects underwent 5 repeated examinations with the Corvis ST.The intraclass correlation coefficient (ICC), Cronbach α coefficients and repeatability coefficient (RC) were computed to evaluate repeatability of Corvis ST parameters.The multiple linear regression analysis was used to study the factors that affect the magnitude of the test-retest variability (within subject SD) of new Corvis ST parameters.This study was approved by the Ethics Committee of Henan Eye Hospital (HNEECKY-2019[5]), and written informed consent was obtained from each subject.@*Results@#Among the 39 biomechanics parameters, The ICC and Cronbach α were greater than 0.75 for 26 parameters, within 0.60-0.75 for 4 parameters, and lower than 0.60 for deflection amplitude max time (DLAMT). The ICC and Cronbach α of DA ratio max[1 mm], DA ratio max [2 mm], max inverse radius, Ambrósio's relational thickness horizontal (ARTh), biomechanical intraocular pressure (bIOP), integrated radius, stiffness parameter applanation 1 (SPA1) and Corvis biomechanical index (CBI)were all above 0.920.The multivariate regression results indicated that the within subject SD of bIOP increased with the increase of IOP (β=0.210, P=0.010). The within subjects SD of DA Ratio Max [1 mm]decreased with the increase of central corneal thickness (CCT) (β=-0.218, P=0.008). The within subjects SD of DA Ratio Max [2 mm]decreased with the increase of CCT(β=-0.295, P<0.001). The within subject SD of CBI decreased with the increase of astigmatism, axial lengths and CCT (β=-0.190、-0.148、-0.428, all P<0.05).@*Conclusion@#The Corvis ST parameters showed favorable measurement repeatability in myopia patients, especially for the new parameters.Astigmatism, axial lengths and CCT significantly affected the repeatability of CBI.
ABSTRACT
ENoG is regarded as a valuable method for quantitatively assessing facial nerve function, however it is occasionally discorrelated with clinical findings. So its utility may be diminished, especially in the serial tests. So, we endeavored to find the suitable position of recording electrode in test-retest variability of ENoG. We performed the test five times individually in 18 healthy adults(all males) volunteers. The recording electrodes were placed at 3 different positions(whole nasolabial fold(A), 2/3 portion of the nasolabial fold(B), 1/2 portion of the nasolabial fold(C)). And then we compared the results between action potentials of 3 different positions. The amplitude was more stable at B or C than A. The mean interside variance(ISV) of individuals was less than 50% except one case at A, and there was no significant difference among them(p>or=0.05) except two persons between A and C(p<0.05). In the test-retest variability, the mean was 20.03%(A:20.66+/-10.72%, B:23.75+/-12.60%, C:15.69+/-10.21%). There was more smaller mean and standard deviation at C than others. So, we recommand the 1/2 of the nasolabial fold as the available position in the serial ENoG recordings.
Subject(s)
Humans , Action Potentials , Electrodes , Facial Nerve , Nasolabial Fold , VolunteersABSTRACT
ENoG is the objective electrophysiologic measurement of the muscle compound action potential(CAP) to assess the rate of degenerated nerve fibers. However, occasional discorrelation with clinical findings may diminish the utility of the ENoG. So, we studied the significance of recording electrode placement, which is considered to affect the result of the ENoG. We performed the interside variance in 20 healthy adults(20 males) volunteers and retest was performed in 6 adults of 20 volunteers. The recording electrode was placed at 3 positions.(whole nasolabial fold(A), 2 / 3 of the nasolabial fold(B), 1 / 2 of the nasolabial fold(C)) And then we compared the results: 1) In the first measurement, the mean CAP was 3.02+/-0.98mV(A), 2.80+/-0.75mV(B), 2.56+/-0.57mV(C) on the right side, 2.70+/-1.02mV(A), 2.50+/-0.90mV(B), 2.33+/-0.86mV(C) on the left side, and there was no significant difference between right and left inter-side amplitude(p>or=0.05). 2) In the first measurement, the mean interside variance(ISV) was 32.7%(37.55+/-16.32%(A), 29.88+/-17.15%(B), and 30.67+/-18.56(C)) and there was no significant difference among them(A, B, C)(p>or=0.05). The minimal individual ISV was 20.35+/-12.44%. There was significant difference between it and the other individual 3 positions(por=0.05). The minimal individual ISV was varied in each testing at 3 positions. And the value was 14.32+/-2.69%. There was no significant difference between it and other 3 postions(p>or=0.05). So we recommand that the recording electrode may be fixed at the bilateral same position of the nasolabial fold. But if there is any indication of facial nerve decompression, you must find the best recording electrode position to get the minimal ISV before operation.