Abstract
Purpose::
The aim of this study is to describe four clinical cases of Congenital Stationary Night Blindness (CSNB) examined with multifocal electroretinography (mfERG) and the microperimeter MP-1 and to evaluate the examination methods.
Methods::
We investigated abnormalities of retinal rod and cone ON- and OFF-pathways in 4 patients with congenital stationary night blindness (CSNB). We excluded patients affected by other ocular and systemic pathologies. All subjects underwent a complete ophthalmological examination, multifocal ERG and microperimetry test with the MP-1 (NIDEK technologies). Multifocal ERG was performed using the RETIscan system with a binary m-sequence technique. Evaluation was performed for the first-order kernel concentric ring segments (2, 4, 10 degrees). Retinal sensitivity was recorded concerning 2,4 and 10 degrees around the fixation target; fixation stability percentage was evaluated for 2 and 4 degrees using microperimeter MP-1.
Results::
Our data show that the setup of mfERG with the MP-1 provides a topographic map of retinal function subdivided into stimulation areas that add more informations about photoreceptor status than the conventional examinations.CASE 1: T.M., male 27 years.mfERG signal (4°): 110 nV RE, 58,8 nV LE.Retinal sensitivity (4°): 13,6 dB RE, 18,1 dB LE.Fixation stability (4°): 99 % RE, 100% LE.CASE 2: T.S., female, 24 years.mfERG signal (4°): 44 RE, 73,7 nV LE.Retinal sensitivity (4°): 11,6 Db RE, 12,8 dB LE.Fixation stability (4°): 97 % RE, 100% LE.CASE 3: R.M.L., female 27 years.mfERG signal (4°): 103 nV RE, 136 nV LE.Retinal sensitivity (4°): 19,4 dB RE, 19,6 dB LE.Fixation stability (4°): 100% RE, 100% LE.CASE 4: Z.M., female, 42 years.mfERG signal (4°): 50,7 nV RE, 110 nV LE.Retinal sensitivity (4°): 14,7 dB RE, 14,4 dB LE.Fixation stability (4°): 95% RE, 89% LE.
Conclusions::
CSNB is a group of nonprogressive retinal disorders characterized by impaired night vision. Among others the electroretinogram(ERG) is substantial in the diagnosis and to distinguish different types of CSNB but nowadays there are two new methods available for function testing of the retina, multifocal Electroretinography (mfERG) as well as fundus perimetry with the microperimeter MP-1.
Keywords: electroretinography: clinical • retina • perimetry