The Detection Of Misrouting In Albinism: Evaluation of Different VEP Procedures in a Heterogeneous Cohort

Purpose: To investigate the optimal procedures for multichannel visually evoked potentials (VEPs) to detect misrouting in albinism subjects.

Methods: Investigations were done in a phenotypically heterogeneous group of 180 albinism subjects and 187 controls with and without ocular pathology. We retrospectively compared standard flash VEP (fVEP), high-frequency fVEP with a handheld device (hh fVEP), pattern-onset VEP (poVEP), and short-onset acuity sweep VEP. The diagnostic power of these stimuli were estimated by calculating the area under the curve (AUC). Subjects were divided in three age groups (<3, 3-6 [toddler], and ≥6 years). Subjects ≥6 years of age were further divided in two visual acuity groups (≤0.3 logMAR and >0.3 logMAR).

Results: The optimal stimulus was hh fVEP, standard fVEP, and poVEP 60' for subjects <3, 3-6, and ≥6 years of age, respectively. In subjects ≥6 years old with poor visual acuity, the area under the curve of fVEP was almost equal to that of poVEP 60'.

Conclusions: For the optimal detection of misrouting with multichannel VEP recordings, we recommend using a high-frequency hh fVEP in children <3 years of age, standard fVEP in toddlers, and poVEP 60' in subjects ≥6 years of age. fVEP can also be used in the oldest age group for subjects with visual acuity of >0.3 logMAR. Remarkably, some albinism subjects showed misrouting on full-field stimulation but normal routing of the central retina, suggesting that not the whole line of decussation is shifted temporally.