A mixed distribution of empirical variances, composed of two distributions the basic and contaminating ones, and referred to as PERG mixed distribution of empirical variances, is considered. In the paper a robust inve...A mixed distribution of empirical variances, composed of two distributions the basic and contaminating ones, and referred to as PERG mixed distribution of empirical variances, is considered. In the paper a robust inverse problem solution is given, namely a (new) robust method for estimation of variances of both distributions—PEROBVC Method, as well as the estimates for the numbers of observations for both distributions and, in this way also the estimate of contamination degree.展开更多
Aim:To characterise and monitor abnormal fundus autofluorescence(AF)in patients with retinitis pigmentosa(RP)who have good visual acuity.Methods:21 patients with a clinical diagnosis of RP were examined.All had rod-co...Aim:To characterise and monitor abnormal fundus autofluorescence(AF)in patients with retinitis pigmentosa(RP)who have good visual acuity.Methods:21 patients with a clinical diagnosis of RP were examined.All had rod-cone dystrophy(ISCEV standard electroretinograms(ERGs)),visual acuity of 6/9 or better,and manifested a parafoveal ring of high density fundus AF.Repeat AF imaging was performed after periods of between 2 years and 5 years in 12 patients.Pattern ERG(PERG)and multifocal ERG(mfERG)were performed in 20 cases.Visual fields(VF),photopic and scotopic fine matrix mapping and small field PERGs were performed in representative cases.Results:The rings of high density AF varied in size between patients(from 4°-16° diameter).MfERGs showed relative preservation over the central macular area,correlating with the size of AF ring and with PERG and psychophysical data.Progressive constriction of the AF ring was demonstrated at follow up in three patients.Serial PERG,mfERG,and VFs,performed in one of these cases,showed evidence of deterioration concordant with ring constriction.Conclusions:High density rings of AF,seen in some patients with RP with good visual acuity,demarcate areas of preserved central photopic function.MfERGs correlate with the area encircled by high density AF and the PERG data.The size of the ring of AF can show progressive constriction accompanied by increasing macular dysfunction.展开更多
文摘A mixed distribution of empirical variances, composed of two distributions the basic and contaminating ones, and referred to as PERG mixed distribution of empirical variances, is considered. In the paper a robust inverse problem solution is given, namely a (new) robust method for estimation of variances of both distributions—PEROBVC Method, as well as the estimates for the numbers of observations for both distributions and, in this way also the estimate of contamination degree.
文摘Aim:To characterise and monitor abnormal fundus autofluorescence(AF)in patients with retinitis pigmentosa(RP)who have good visual acuity.Methods:21 patients with a clinical diagnosis of RP were examined.All had rod-cone dystrophy(ISCEV standard electroretinograms(ERGs)),visual acuity of 6/9 or better,and manifested a parafoveal ring of high density fundus AF.Repeat AF imaging was performed after periods of between 2 years and 5 years in 12 patients.Pattern ERG(PERG)and multifocal ERG(mfERG)were performed in 20 cases.Visual fields(VF),photopic and scotopic fine matrix mapping and small field PERGs were performed in representative cases.Results:The rings of high density AF varied in size between patients(from 4°-16° diameter).MfERGs showed relative preservation over the central macular area,correlating with the size of AF ring and with PERG and psychophysical data.Progressive constriction of the AF ring was demonstrated at follow up in three patients.Serial PERG,mfERG,and VFs,performed in one of these cases,showed evidence of deterioration concordant with ring constriction.Conclusions:High density rings of AF,seen in some patients with RP with good visual acuity,demarcate areas of preserved central photopic function.MfERGs correlate with the area encircled by high density AF and the PERG data.The size of the ring of AF can show progressive constriction accompanied by increasing macular dysfunction.
