Improvement of scotopic electroretinograms and night blindness with recovery of serum zinc levels.
BACKGROUND
We sought to determine the cause of reduced scotopic and photopic electroretinograms (ERGs) and night blindness in a 46-year-old man with liver dysfunction but no history of alcoholism.


METHODS
A 46-year-old Japanese man with a complaint of visual difficulties in dim light for 1 month.


METHODS
By electrophysiological investigation, the patient was found to have low levels of serum zinc and vitamin A on admission. The rod b wave was unrecordable, and the bright-flash ERGs were reduced, with the a wave > b wave. The amplitudes of the cone and 30-Hz flicker responses were also reduced, and their implicit times were prolonged. Three weeks after admission, the patient's serum zinc level recovered to normal levels, but his serum vitamin A level was still low. The symptoms of night blindness were gone, and the rod ERGs and single bright-flash responses were within normal limits. However, the cone ERGs and 30-Hz flicker responses were still depressed.


CONCLUSIONS
The recovery of scotopic function together with the recovery of zinc but not vitamin A levels suggests that the ERG changes were most likely related to low zinc levels.
Mochizuki
Kiyofumi
K
Department of Ophthalmology, JA Gifu Koseren, Chuno General Hospital, Gifu, Japan. mochi-gif@umin.ac.jp.|Department of Ophthalmology, JA Gifu Koseren, Chuno General Hospital, 5-1 Wakakusa-dori, Seki-shi, Gifu, 501-3802, Japan. mochi-gif@umin.ac.jp.
Murase
Hiroki
H
Department of Ophthalmology, JA Gifu Koseren, Chuno General Hospital, Gifu, Japan.
Imose
Motoaki
M
Department of Internal Medicine, JA Gifu Koseren, Chuno General Hospital, Gifu, Japan.
Kawakami
Hideaki
H
Department of Ophthalmology, Gifu University School of Medicine, Gifu, Japan.
Sawada
Akira
A
Department of Ophthalmology, Gifu University School of Medicine, Gifu, Japan.
D002756:Cholagogues and Choleretics / Q000008:administration & dosage; D003623:Dark Adaptation; D004596:Electroretinography; D005451:Fluorescein Angiography; D006801:Humans; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D009755:Night Blindness / Q000097:blood / Q000503:physiopathology*; D010775:Photic Stimulation; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology*; D020127:Recovery of Function; D014794:Visual Fields; D014801:Vitamin A / Q000097:blood; D014802:Vitamin A Deficiency / Q000097:blood; D015032:Zinc / Q000097:blood* / Q000172:deficiency
D002756:Cholagogues and Choleretics; D014801:Vitamin A; D015032:Zinc