Diksha Rathi, B.Optom

M. Optom Student, The Sankara Nethralaya Academy, Chennai, India



Visual Snow Syndrome (VSS) is a commonly misdiagnosed neurological condition characterised by mild to severe, persistent visual abnormalities. (1) Constant flashing dots or static, throughout the visual field known as visual snow is the defining symptom of the condition. The pathophysiology of VSS is still unclear; research states there are alterations in different brain areas which are associated with visual processing. (1,2) Diagnosis of VSS requires the existence of Visual Snow (VS) for more than 3 months, alongside at least two of the following symptoms, namely: –

  1. Blue field entoptic phenomenon
  2. Floaters,
  3. Nyctalopia,
  4. Palinopsia,
  5. Photopsia,
  6. Photophobia.

VSS patients are also reported to have tinnitus, migraines, depersonalisation, anxiety, depression, concussion, and fibromyalgia. (34) Patients with visual snow are observed to have a decreased quality of life, as they face difficulties in activities of daily living such as driving, reading, utilising technology, going out at night, being in bright light areas and exercising also affect them (Figure 1). (1]

There are instances of successful treatment of VSS with amitriptyline, based on the hypothesis that VSS is a form of pituitary fatigue and peripheral neuropathy.(1,2,5)

Figure 1: Sight with Visual Snow Syndrome
Picture courtesy: https://www.allaboutvision.com/conditions/related/visual-snow-syndrome/


Neuro-optometric Rehabilitation Therapy (NORT) consists of 12 in office therapy sessions of 60 minutes including 3-5 exercises and visual home assignments. Home-based vision therapy is to be performed for 12 weeks, 5 days in a week. (1) NORT is to be implemented based on the individual’s ocular findings such as accommodation, vergence, binocular vision skills and oculomotor skills. It includes therapies to develop:-

  1. Proprioceptive awareness of the eyes in physical space
  2. Peripheral awareness
  3. To use visual-spatial skills to help and guide motor planning
  4. To perform high level saccadic eye movements
  5. To develop and enhance visual and vestibular connection
  6. To improve eye-hand coordination

Some computer-based therapeutic instruments like Binovi, Sanet Vision Integrator (SVI) can be used to enhance pursuits, saccades, fixation stability, eye-hand coordination, visual reaction time, speed and span of recognition, automaticity, contrast sensitivity, plus visual and auditory sequencing, and memory. (1)

Vestibular Ocular Reflex (VOR) exercise allows eyes, inner ears, and brain to enhance processing. Vision therapy systems include complex monocular and binocular stimuli to allow automatic testing and measurement of pursuits and saccades, fusional ranges, phorias, motor fields, fixation disparities, suppressions; retinal correspondence, accommodative facility, stereopsis, visual memory, and aniseikonia.(1,3,4) Exercises with yoked prism glasses helps enhance binocular sensory- motor awareness. Visual perceptual processing is the ability to perceive, analyse, synthesise, and think with visual patterns which involves the ability to store and recall information via visual imagery and visual memory. (1,3)

Depending upon the accuracy with which the therapeutic exercise is performed, the next step must be decided. When the therapeutic activity is performed with <70% accuracy, the difficulty level of the activity is to be reduced (unloaded) until the performance improves and then move to the next step. When the activity is performed with >90% accuracy, difficulty level of the activity is to be increased (loaded) and move to the next level or activity. (1)

Quality of Life post NORT

Post NORT, NEI-VFQ-25 composite scores, near and distance vision scores, social functioning, mental health, role difficulties, and dependency scores improved significantly. Activities of daily life can be performed effectively suggesting an improvement in overall quality of life. (1)


NORT could prove to be an effective treatment option in cases of VSS for management of the condition and to ensure an improved quality of life.



  1. Tsang, T., Shidlofsky, C., & Mora, V. (2022). The efficacy of neuro-optometric visual rehabilitation therapy in patients with visual snow syndrome. Frontiers in neurology13, 999336.
  2. Fraser C. L. (2022). Visual Snow: Updates on Pathology. Current neurology and neuroscience reports22(3), 209–217.
  3. Wentzell S, Ryan M (2018) Visual Snow Syndrome: A Case Report and New Treatment Option. Clin Med Rev Case Rep 5:246. doi.org/10.23937/2378-3656/1410246
  4. Ciuffreda, K. J., Tannen, B., Rutner, D., & Han, M. E. (2023). Neuro-optometric treatment for visual snow syndrome: recent advances. Concussion (London, England)8(3), CNC110.
  5. Ciuffreda, K. J., Han, M. E., Tannen, B., & Rutner, D. (2021). Visual snow syndrome: evolving neuro-optometric considerations in concussion/mild traumatic brain injury. Concussion (London, England)6(2), CNC89.