Kenneth J. Ciuffreda, OD, PhD, M.H. Esther Han, OD, Barry Tannen, OD
The clinical condition of “visual snow syndrome” (VSS) is relatively rare and uniquely described in the medical literature (1-15). Its hallmark characterization is the perception of “visual snow” (VS) appearing in a single plane in front of and throughout the entire visual field. VS appears as electronic “snow” on a television set when the primary video signal is either reduced or absent, as well as pixelated fuzz and bubbles(1-15).
In addition to the presence of VS (2-15), the individual must also report two or more of the following to be formally diagnosed with VSS: palinopsia,
enhanced entoptic imagery, “nyctalopia”, and photophobia/photosensitivity. These individuals also frequently report having migraine, photopsia, phonophobia, hyperacusis, cutaneous allodynia, tinnitus, balance problems, and tremor (2-15).
Due to its presumed extremely low prevalence, there is a relative paucity of reports in the literature on VSS in adults dating back to 1944 (1-12) and only three case reports in children and adolescents ages 11-14 years over the past few years (13-15). In these three cases, all conventional medical diagnostic testing was negative (15), and all attempted drug treatments, such as sumatriptan (15), were unsuccessful. None of the pediatric literature reports note successful treatments such as chromatic filters or vision therapy. Neither were successful medications directed solely at VS, only medications toward migraine symptoms or other coincident symptoms. Thus, we present a neuro-optometrically based pediatric case series (ages 10-15 years) of three patients with well-documented VSS. This report includes both valuable diagnostic and therapeutic aspects for the clinician.
Treatment for VSS is important for all individuals, but perhaps even more in young children/adolescents, for several reasons.
First, there is the possible psychological effect of having such unusual and abnormal, undiagnosed, visual percepts. Some adult patients with VSS indicate their childhood reservation about telling this to a friend or family member, for fear of disbelief or ridicule.
Second, those manifesting palinopsia, frequently find their sustained and superimposed afterimage to be both distracting and disruptive when reading. Thus, likely reducing reading rate, visual comfort, and poorer comprehension.
Lastly, as they become of driving age, the presence of VSS, palinopsia, and/or enhanced entoptic imagery, especially at night, may impact adversely on their driving ability and safety due to impaired visual perception and attentional distraction. If so, they should obtain counseling from a professional driving trainer with expertise in those having visual impairment.
A randomized clinical trial (RCT) will assess the efficacy of the two current neuro-optometric therapeutic interventions, namely tinted spectacles, and oculomotor-based vision therapy.