ERG and EOG abnormalities in carriers of X-linked retinitis pigmentosa

Abstract

The diagnosis of X-linked retinitis pigmentosa (XL-RP) relies on the identification of the female carriers, in whom fundal abnormalities are often minimal and variable. The electroretinogram (ERG) has been reported as abnormal in 54-96% of heterozygote females. This study examines the combined use of electro-oculogram (EOG) and standardised ERG in 31 obligate and 33 non-obligate carriers of XL-RP. In the obligate carrier group, the EOG was abnormal in 13 carriers (41%), the ERG abnormal in 21 carriers (68%) and a combined EOG and ERG abnormality occurred in 24 carriers (77%). An EOG abnormality alone occurred in 2 carriers (6.5%). Fourteen obligate carriers (45%) showed a peak to peak delay of the ERG scotopic b wave, this being a previously unreported phenomenon. Similarly, in the non-obligate carrier group, the EOG was abnormal in 11 carriers (44%) and the ERG abnormal in 19 carriers (73%). The results of this study suggest that the use of both tests, including measurement of the scotopic b wave latency, may increase the carrier detection rate.

Optical coherence tomography and electro-oculogram abnormalities in X-linked retinitis pigmentosa

“…The EOG was not very useful, since almost 36% had a normal ratio even in cases with fundus abnormality [3]. Contrasting with our findings, in a study of 31 obligate carriers of XLRP, alterations to the EOG were detected in only 41% of the cases [12]. The incidence of EOG abnormality increased significantly (p < 0.05) in carries over 40 years of age compared with younger ones [12].…”

“…Contrasting with our findings, in a study of 31 obligate carriers of XLRP, alterations to the EOG were detected in only 41% of the cases [12]. The incidence of EOG abnormality increased significantly (p < 0.05) in carries over 40 years of age compared with younger ones [12]. The EOG can be helpful in the evaluation of carriers with normal or equivocal fundi and equivalent ERG findings [12].…”

“…Normal fundus with abnormal EOG and/or ERG was reported in 16% of obligate carriers [12]. Others have observed that fundus alterations in carriers are also important for visual prognosis counselling because carriers with only a tapetal-like retinal reflex had a better prognosis to retain visual function than those with peripheral retinal pigmentation [13].…”

Alcohol- and Light-induced Electro-oculographic Responses: Variability and Clinical Utility

“…However, similar variability in EOG values has been observed in many other laboratories and is well documented in the literature [25][26][27][28][29]. Lower limits of normal Arden ratios have been reported in some laboratories to be between 1.3 and 1.7 [29][30][31][32][33], and the highest normal values are often in the range of 4.0-5.0. Our own laboratory norms (independent of the current study) consist of values from 1.8 to 4.0.…”

Alcohol- and Light-induced Electro-oculographic Responses in Age-related Macular Degeneration & Central Serous Chorioretinopathy

“…Second, there is a large scatter of Alc-EOG (and Li-EOG) values from both normal subjects as well as patients with ARMD or CSC, and this spread of data could mask modest effects of disease. While some of our Alc-EOG data spread may be due to variability in BAC levels associated with oral alcohol administration, there is similar inter-individual variability in the Arden ratio, for which no alcohol is involved [23,[25][26][27][28]. These issues are discussed in more detail in our companion paper [15].…”