Multifocal electroretinogram in non-pathological myopic subjects:correlation with optical coherence tomography

AIM： To investigate the changes of retinal function in non-pathological myopic subjects using multifocal electroretinography （mfERG） and to correlate the data with the central macular thickness obtained using optical coherence tomography （OCT）. ~ METHODS： One hundred and thirteen subjects （113 eyes） with age range from 18 to 35y were enrolled in the study. The subjects were divided into four groups according to spherical equivalent （SE） and axial length （AL）： emmetropia group （EG, n=31; SE： ＋0.75 to -0.50 D; AL： 22 to 24 mm）, low and medium myopia group （LMMG, n=26; SE： 〉-0.50 to -6.00 D; AL： 〉24 to 26 ram）, high myopia group （HMG, n--34; SE： 〉-6.00 to -10.00 D; AL： 〉26 to 28 mm） and super high myopia group （SHMG, n =22; SE： 〉-10.00 D; AL： 〉28 mm）. The P1 amplitude density, P1 amplitude, and P1 implicit time of the first- order kernel mfERG responses were obtained and grouped into five rings. The central subfield macular thickness （CST） was obtained using macular cube 512x218 scan of Cirrus HD-OCT. RESULTS： With the increasing of eccentricity, the first positive peak （P1） amplitude density （P=0.0000, 0.0001, 0.0021 in ring 1-3 respectively） and P1 amplitude （all P= 0.0000 in ring 1-5） of each group decreased. With the increasing of myopia, P1 implicit time gradually extended （all P=0.0000 in ring 1-3）. The average CST in four diagnostic groups was 241.56±12.72um, 244.56±12.19um, 254.33±11.61um, 261.75±11.83um respectively. With the increasing of myopia, CST increased （P〈0.001）. There was negative relationship between CST and P1 amplitude, P1 amplitude density （r =-0.402, P〈0.001; r= -0.261, P =0.003）. There was positive relationship between CST and P1 implicit time （r=0.34, P〈0.001）.~ CONCLUSION： With the increasing of myopia, P1 amplitude density and P1 amplitude of the first-order reaction gradually reduced. This showed potential decline in retinal function in myopia. To some extent it may reflect the functional disorder or depression of the visual cells, The exact mechanism needs further study,

Comparison of ultrasound biomicroscopy and spectraldomain anterior segment optical coherence tomography in evaluation of anterior segment after laser peripheral iridotomy

AIM：To quantitatively assess narrow anterior chamber angle using spectral-domain anterior segment optical coherence tomography（SD-AS-OCT） and ultrasound biomicroscopy（UBM）,and to evaluate the correlations and consistency between SD-AS-OCT and UBM.· METHODS：Fifty-five eyes from 40 patients were examined.Patients were diagnosed with primary angleclosure glaucoma（PACG） remission（11 eyes from 8patients）,primary angle closure（PAC,20 eyes from 20patients） and PAC suspect（24 eyes from 12 patients）.Each eye was examined by SD-AS-OCT and UBM after laser peripheral iridotomy（LPI）.The measurements of SD-AS-OCT were angle open distance（AOD）,anterior chamber angle（ACA）,trabecular iris angle（TIA）,and trabecular iris space area（TISA）.UBM measurements were AOD and TIA.Correlations of AOD500 and TIA500 between UBM and AS-OCT were assessed.All parameters were analysed by SPSS 16.0 and MedCalc.· RESULTS：ACA,TIA and AOD measured by SD-ASOCT reached a maximum at the temporal quadrant and minimum at the nasal quadrant.Group parameters of AOD500 and AOD750 showed a linear positive correlation,and AOD750 had less variability.UBM outcomes of AOD500 and TIA500 were significantly smaller than those of SD-AS-OCT.The results of the two techniques were correlated at the superior,nasal and inferior quadrants.CONCLUSION：Both UBM and SD-AS-OCT are efficient tools for follow-up during the course of PACG.We recommended using parameters at 750 μm anterior to the sclera spur for the screening and follow-up of PACG and PAC.The two methods might be alternatives to each other.

A new diagnostic model of primary open angle glaucoma based on FD-OCT parameters

AIM： To build a clinical diagnostic model of primary open angle glaucoma （POAG） using the normal probability chart of frequency-domain optical coherence tomography （FD-OCT）. METHODS： This is a cross-sectional study. Total 133 eyes from 133 healthy subjects and 99 eyes from 99 early POAG patients were included in the study. The retinal nerve fibre layer （RNFL） thickness parameters of optic nerve head （ONH） and RNFL3.45 scan were measured in one randomly selected eye of each subject using RTVue-100 FD-OCT. Then, we used these parameters to establish the diagnostic models. Four different diagnostic models based on two different area partition strategies on ONH and RNFL3.45 parameters, including ONH traditional area partition model （ONH-T）, ONH new area partition model （ONH-N）, RNFL3.45 traditional area partition model （RNFL3.45-T） and RNFL3.45 new area partition model （RNFL3.45-N）, were built and tested by cross-validation. RESULTS： The new area partition models had higher area under the receiver operating characteristic （AROC; ONH-N： 0.990; RNFL3.45-N： 0.939） than corresponding traditional area partition models （ONH-T： 0.979; RNFL3.45-T： 0.881）. There was no statistical difference among AROC of ONH-T, ONH-N, and RNFL3.45-N. Nevertheless, ONH-N was the simplest model. CONCLUSION： The new area partition models had higher diagnostic accuracy than corresponding traditional area partition models, which can improve the diagnostic ability of early POAG. In particular, the simplest ONH-N diagnostic model may be convenient for clinical application.