Disclaimer: I am neither an optometrist nor vision researcher/specialist. The content I reference are lectures that were given at various COVD conferences for those kinds of professionals. I have no vested interest in any products that promote the sale of treatments for these ailments. I do have a vested interest in the sale of the recorded content of these conference lectures. All the lectures are behind a paywall. Sorry.
Aside from the articles you've already linked and the one in the comments below your question, I cannot find any other studies that correlate Strabismus and Psychological illness. However, I have access to some continuing education material, and I did find information on the following correlations:
- Vision deficiencies such as strabismus and Neurologic disease (e.g. brain tumors)
- Convergence insufficiency and ADHD
- Acquired brain injury presenting vision deficiencies and psychological illness.
Vision deficiencies and neurologic disease
In the lecture The Important Intersection Between Vision Therapy and Neurologic Disease by David A. Damari, OD - Spring 2015 COVD General Education Conference (lecture 4 under General Education), Dr. Damari notes that there is known relationships with certainly visionary issues and Neurologic disease, and urges optometric practitioners to refer them to neurologists, not ophthalmologists. He references two comprehensive sources on the issue:
- Miller and Newman Walsh & Hoyt's Clinical Neuro-Ophthalmology (The Essentials), LW&W
- Kline Neuro-Ophthalmology Review Manual, Slack
Convergence Insufficiency and ADHD
In the lecture The Uses of Vision Therapy in Treating School Age Children Diagnosed with Attention Problems by Darrell G. Schlange, OD - Spring 2015 COVD General Education Conference (part of lecture 11, "oral research presentations"), the speaker shows that Convergence Insufficiency (CI) is highly associated with ADHD. CI is somewhat different than Strabismus, however, it is characterized as a binocular visionary disorder whereby the eyes have a tendency to drift outward when working on near field tasks, such as reading, rather than converge the lines of sight for each eye on a single point (source). This, to me, sounds very similar to strabismus, however, strabismus is most often caused by physical deficiencies with the eye, where CI is commonly not associated with physical deficiencies.
Among others, these sources are mentioned and quoted in that lecture:
The lecture Behavioral and Emotional Problems Associated with Convergence Insufficiency in Children by Eric Borsling OD, MS, MSEd - Fall 2012 COVD General Education Conference (lecture 4), corroborates this correlation referencing primarily A Randomized Clinical Trial of Treatments for Convergence Insufficiency in Children (CITT). The conclusions include that a randomized clinical trial is needed to study the impact of successful treatments, children with ADHD should be screened for CI, and children with ADHD may be at higher risk for CI.
Acquired brain injury presenting vision deficiencies and psychological illness
Within the two day workshop Patients with Acquired Brain Injury by Cathy Stern, OD, Dr. Stern notes that a brain trauma can sometimes cause a strabismus, among other vision deficiencies. No source was given, but this was said and accepted by the audience as if it is common knowledge. A quick Google search seems to indicate this as well. However, brain injury is not a psychological issue, though it may bring about psychological issues (i.e. depression, anxiety, etc.). Uncaught brain injury may be causing an increase in the correlation between strabismus and psychological illness. Dr. Stern advises that practitioners take care to isolate genuine brain injury from non-brain injury occurring vision deficiencies. Dr. Stern lists the following sources for the diagnosis and treatment for visual issues stemming from a brain injury:
- Applied Concepts in Vision Therapy by Leonard J. Press, OD
- My Stroke of Insight: A Brain Scientist's Personal Journey by Jill Bolte Taylor, PhD
- Neuro-Optometric Rehabilitation by William V. Padula, OD
- Visual & Vestibular Consequences of Acquired Brain Injury edited by Irwin D. Suchoff, OD et al.
- Visual Agnosia by Martha J. Farah