Rod and rod-driven function in achromatopsia and blue cone monochromatism.
OBJECTIVE
To evaluate rod photoreceptor and postreceptor retinal function in pediatric patients with achromatopsia (ACHR) and blue cone monochromatism (BCM) using contemporary electroretinographic (ERG) procedures.


METHODS
Fifteen patients (age range, 1-20 years) with ACHR and six patients (age range, 4-22 years) with BCM were studied. ERG responses to full-field stimuli were obtained in scotopic and photopic conditions. Rod photoreceptor (S(rod), R(rod)) and rod-driven postreceptor (log sigma, V(max)) response parameters were calculated from the a-wave and b-wave. ERG records were digitally filtered to demonstrate the oscillatory potentials (OPs); a sensitivity parameter, log SOPA(1/2), and an amplitude parameter, SOPA(max), were used to characterize the OP response. Response parameters were compared with those of 12 healthy control subjects.


RESULTS
As expected, photopic responses were nondetectable in patients with ACHR and BCM. In addition, mean scotopic photoreceptor (R(rod)) and postreceptor (V(max) and SOPA(max)) amplitude parameters were significantly reduced compared with those in healthy controls. The flash intensity required to evoke a half-maximum b-wave amplitude (log sigma) was significantly increased.


CONCLUSIONS
Results of this study provide evidence that deficits in rod and rod-mediated function occur in the primary cone dysfunction syndromes ACHR and BCM.
Moskowitz
Anne
A
Department of Ophthalmology, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA. anne.moskowitz@childrens.harvard.edu
Hansen
Ronald M
RM
Akula
James D
JD
Eklund
Susan E
SE
Fulton
Anne B
AB
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003117:Color Vision Defects / Q000503:physiopathology*; D003623:Dark Adaptation / Q000502:physiology; D004596:Electroretinography; D005260:Female; D006801:Humans; D007223:Infant; D008027:Light; D008297:Male; D009991:Oscillometry; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D012164:Retinal Diseases / Q000503:physiopathology*; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D017299:Rod Opsins / Q000502:physiology
D017299:Rod Opsins; C095853:short-wavelength opsin