For some strabismatics, especially those presenting with a normal appearance, focusing and resulting eye strain headaches only emerge in early adulthood or middle age. Even those for aware of their condition, its relation to visual deficits had never been explained or explored. The partner of a high school gym teacher, for example, asked for a consult, pleading, I “do something to get him help. I’m afraid to drive in a car with him.”  A treating ophthalmologist had informed him of his strabismus for the first time.  “So that’s why I was never really able to catch a ball!” the teacher said. The congenital lack of depth perception explained for the first time why he could coach but had difficulty playing games requiring binocular vision like baseball, football, tennis, or squash. Understanding that, he said, was itself a relief. But absent cosmetically obvious deviations, his ophthalmologist insisted strabismus had no causal relation to his patient’s increasing focal difficulties or his persistent head aches. Progressively stronger corrective lenses prescribed provided little relief.

Finally, after referral to an optometrist specializing in adult strabismus, he was prescribed corrective lenses with Fresnel prisms and only a modest correction for presbyopia. The incidence of blurred vision and eye strain headaches immediately decreased as a result. At the same time his driving abilities, his partner reported, improved. A regime of frequent rests during taxing visual assignments—grading tests or writing students reports, for example—further helped diminish reported symptoms.

Others similarly reported the failure of early diagnosis and problems presenting in adulthood from a lack of depth perception. For these patients, understanding their strabismus and its effect explained a history of psychosocial difficulties. For example, an adult male in his 40’s with no cosmetic deviation presented with eye strain headaches and decreasing acuity. Stronger prescriptions for myopia and presbyopia had little effect. When informed the likely cause of his symptoms was congenital strabismus, and a resulting lack of binocular vision, he was furious. He had lived with the burden of feeling always clumsy, inept and inadequate. “I paid an enormous emotional price for always being the last kid picked for any baseball game which of course I had to play daily at the various camps I went to as a kid,” he said. In his very sports-oriented family—two older brothers excelled at hockey and ball-based sports—his father was especially dismissive of his youngest son’s athletic limits.

The complaint that life might have been different with earlier diagnosis and treatment was similarly reported in an earlier case study describing the difficulties faced by a woman first diagnosed with concomitant strabismus in her late 30’s [15]. Aa a child she had been told her eccentric head tilt, an adaptation by some to strabismus [16], was caused by congenital scoliosis. Treating physicians assumed that was also the source of her chronic neck, shoulder and back pain. Diminished visual acuity as well as frequent headaches were unsuccessfully treated and may have been exacerbated by progressively stronger corrective lens prescriptions.

Following corrective surgery at the age of 39 years she experienced temporary relief from her symptoms including the almost complete absence of chronic pain. After several weeks, however, persistent neck and back pain recurred as her body attempted to accommodate to a different posture without the anomalous head positions. On examination, neck and shoulder muscles were asymmetric as the result of weight lifting, she had employed in an attempt to strengthen her back. Focal difficulties also returned resulting in depression and suicidal ideation.

First, the return of discomfort and pain requiring a long course of physical therapy was in itself depressing. In addition, she reported anger at “everyone” who she said had failed her as a child. That included the pediatric ophthalmologist who had not diagnosed her condition, her mother (“she should have protected me”), school mates who mocked her “stand-offish” appearance and teachers who didn’t understand or support her. She blamed her strabismus, its resulting eye strain ad thus reading challenges for a failure to advance professionally. It required three years of psychotherapy and physiotherapy as well as pain relief medication supervised by a family physician before she learned to function without normally. 

 “Quality of life” concerns simply do not adequately address the distress and discomfort that accompanied a lack of fusion in adults [17]. With others in this informal survey, a woman formally diagnosed for the first time at the age of 27 remembered “getting headaches quite often and always wondered if it was from my eyes being strained all the time.” Repeated visits to physicians over the years resulted in ineffective treatments “Every eye doctor I had gone to figured I just needed a stronger prescription [but] I knew my eyes were getting worse. I remember one day I was riding on the chair lift and I saw someone skiing down alongside a rope and I couldn't tell which side of the rope he was on … Later, I was driving and got really scared because I couldn't tell which lane the car in front of me was in. That's when I REALLY knew something was wrong.”

Finally, corrective surgery was prescribed with the warning that afterward some form of eye therapy might be necessary. Immediately following surgery there was a radical but temporary improvement in her vision. “I felt like I was seeing clear and 20/20.  But after a month or so, things started getting a bit fuzzy again.”  She struggled “differentiating whether I was seeing blurry or double,” squinting in an attempt to improve her focusing. 

In passing it is important to note that while state and provincial jurisdictions in North America may test potential drivers for binocular vision it is nowhere a license requirement. In most states and Canadian provinces drivers need only demonstrate visual acuity of a minimum 20/40 in one eye with corrective lenses. The exceptions are Georgia, requiring an acuity only measured at 20/60, and Tennessee where the requirement is 20/35.

Not all those experiencing diplopia found it a handicap when driving. A woman in her 20’s diagnosed as a child had not been informed her lack of stereoscopic vision resulted from the strabismus she assumed was only cosmetically significant. She denied a lack of stereoscopic vision affected her driving or other, daily activities. Her episodic diplopia, sometimes fuzzy vision and chronic “clumsiness” were simply facts of life to be accepted like the cosmetic eccentricities resulting from her exotropia. Admittedly, there were a number of “dings” and “bumps” on the passenger side of her car. But because she never entered from any but the driver’s side she rarely had to see them. On trips through New England to Quebec, where signage switched from English to French, she reported experiencing episodic diplopia. But that was not a concern, she said, because being monolingual she could not read French with either eye. Thus she simply ignored highway signs as they and the roads stacked, side by side, in her doubled vision.