Association of pendular waveform and retinal disorders
Reviewed by Fiona Rowe

The authors aimed to evaluate the relationship between retinal disorders and pendular low amplitude high frequency components (PLAHF) waveform by collecting nystagmus eye movement recordings, electroretinography (ERG) and gene tests. Retinal disorders were diagnosed by clinical phenotype and genotype characteristics. The study included 136 patients (76 male) with a mean age of 11.5 years. Nystagmus onset was within six months of birth. Pure PLAHF waveform was noted in 38 patients (28%) and superimposed PLAHF was noted in 98 patients (72%). Sixty-nine percent had best corrected visual acuity (BCVA) <1.0 logMAR, 22% with 0.5 to 1.0 and 9% with acuities better than 0.5 logMAR. Exotropia was present in 58 patients and esotropia in six. Macular fovea hypoplasia was noted in 70% on optical coherence tomography (OCT) with retinal thinning in 68%. Abnormal on / off visual evoked potential (VEP) was present in 85%. All patients had low f-ERG responses. Gene tests were available for 52 patients and 46 had retinal gene mutations. This study shows that all patients with PLAHF waveform / components also developed retinal disorders during childhood, indicating that PLAHF may be caused by retinal disorders or at least are related to retinal disorders. The authors recommend that patients with PLAHF be referred for ERG and gene testing.

Nystagmus with pendular low amplitude, high frequency components (PLAHF) in association with retinal disease.
Wang P, Ya P, Li D, et al.
STRABISMUS
2020;29(1):3-6.