Fiona M. Dolan

Wide field multifocal and standard full field electroretinographic features of hemi retinal vein occlusion.

The purpose of this study was to document the standard full field electroretinographic (ERG) and wide field multifocal electroretinographic (WF-mfERG) findings in eyes with recent onset hemi-retinal vein occlusion (HRVO) and to compare the electro-diagnostic findings in the affected and fellow eyes with reference to normative data. Eight patients with HRVO were assessed using ERG and WF-mfERG. WF-mfERG first order responses from the affected hemi-retinae and the unaffected hemi-retinae in each affected eye were compared. WF-mfERG responses from each affected hemi-retina and from the symmetrical hemi-retina of each fellow eye were compared. ERG responses between affected and unaffected eyes were also compared. All electrodiagnostic tests were compared to normative data (5–95% confidence limits derived from age-related controls). WF-mfERG P1 and N1 implicit times were greater for the affected hemi-retinae than for the unaffected hemi-retinae (p <0.05). WF-mfERG N1 and P1 implicit times were prolonged (p < 0.05) and WF-mfERG P1/N1 amplitude ratios were significantly reduced (p < 0.05) for the affected eyes when compared with the fellow eyes. Maximal b-wave, cone b-wave and flicker implicit times were prolonged (p < 0.05) when comparing affected and fellow eyes. These results indicate that retinal injury due to HRVO culminates in significant delay of both ERG and WF-mfERG implicit times. These results suggest that WF-mfERG in combination with ERG may have a role in the management of HRVO.

The wide field multifocal electroretinogram reveals retinal dysfunction in early retinitis pigmentosa

The diagnosis of retinitis pigmentosa (RP) is made on the basis of characteristic retinal pigmentation changes, visual field defects, and reduction in amplitude or loss of rod scotopic standard electroretinography (ERG) responses, with a possible history of night blindness and a positive family history of RP.1 Multifocal electrophysiology (mfERG), is a new technique that constructs a topographical map reflecting retinal function.2 Reports have suggested that the spatial resolution of mfERG is sufficient to detect focal changes in retinal function as RP progresses.3–5 We describe a case of early RP in which the amplitude and implicit times of the patients standard ERG rod and maximal responses were normal in the right eye and equivocal in the left eye. However, the peripheral retinal mfERG amplitude and implicit times were reduced and delayed. These abnormalities were obtained using a custom built wide field mfERG,6 which facilitates assessment of a 90 degree retinal field. A 29 year old woman was …

Recovery of visual function in a patient with birdshot chorioretinitis

Birdshot chorioretinopathy (BSCR) is a rare inflammatory disease, which generally follows a chronic course of progressive loss of vision to 6/60 or worse.1 However, the vision may stabilise1 or, rarely, improve slightly.2 Commonly prescribed treatment regimens, including oral steroids, and one or two immunosuppressive agents, may stabilise but generally do not cure the condition.3 We describe a case of BSCR in which there was a marked improvement in Snellen acuity and retinal function, measured with wide field multifocal electroretinography (WF-mfERG),4,5 in a patient intolerant of conventional treatment, who self medicated with an antioxidant preparation. A 53 year old white woman was referred with a 2 year history of decreased vision and floaters affecting both eyes. Snellen acuity was 6/24, N8 in the right eye and 6/12, N8 in the left eye. Moderate vitritis, cystoid macular oedema, swelling of the optic discs, and the presence of scattered, deep, pale creamy white lesions, were compatible with a diagnosis of BSCR, supported by positive HLA-A29 serology. A reducing dose of oral prednisolone in conjunction with cyclosporin was commenced. There was no improvement in visual …