Negative electroretinogram in the differential diagnosis of malingering of night blindness in the military.

OBJECTIVE

We evaluated the value of unusual electroretinogram (ERG) findings (negative ERG, which is selective reduction in the amplitude of the b-wave) in the differential diagnosis of night blindness in the military.

METHODS

We surveyed 3 years of data. Presumptive and final clinical diagnoses before and after negative ERG recordings were evaluated.

RESULTS

A total of 495 ERGs were included. The mean age was 22 +/- 2.5 years (range, 20-33 years). Twenty-two patients (4.4%) had negative ERG. Final clinical diagnoses could be made for all except two patients (9%). The diagnoses were congenital stationary night blindness (CSNB) (14 patients), X-linked juvenile retinoschisis (five patients), and muscular dystrophy (one patient). Seven (50%) of 14 patients with CSNB had normal fundal appearance, symptoms of night blindness, and a presumptive clinical diagnosis of malingering before the ERG test.

CONCLUSION

Negative ERG may prevent misdiagnosis of malingering for patients with CSNB with normal fundal appearance in the military.