Adie’s tonic pupil: Significance in aviators and aeromedical disposal

Abstract

Adie’s tonic pupil is a benign, usually unilateral, pupillary syndrome, in which a larger than normal pupil responds minimally, if at all, to light, but constricts slowly and tonically to a near stimulus (light-near dissociation) and has cholinergic super-sensitivity. It induces impaired near vision, glare, photophobia, and difficulty with dark adaptation, which may not be conducive in a flying environment. A Weapon System Operator of a fighter aircraft with an isolated dilated pupil was assessed over approximately 3 years – right from the beginning until his condition became stable. His condition was not considered an absolutely disabling condition for aviation and he was finally retained in flying in the restricted medical category. The important aspects considered in the aeromedical assessment were – neurological assessment; ophthalmic issues such as tolerance to glare and visual acuity; anisocoria and the executive report on flying concerning visual response to bright sunlight, ability to read maps and MFDs, and ability to identify ground features and spot another ac in bright light conditions. The aviator did not have any neurological, traumatic, or systemic condition/Adie’s syndrome. The tonic pupil stabilized at 4 mm and there was an anisocoria of 2 mm. Light-near dissociation persisted. His executive report was uncomplimentary concerning spotting another aircraft in bright sunlight in the air-superiority fighter (which flies at a max speed of 2120 kmph) as his eyes were getting shut by the glare. However, he could read MFDs, maps, and pick up ground features comfortably and satisfactorily. Hence, considering that Navigation in a transport ac was his parent branch (max speed 452 kmph), he was advised a trial on that ac to assess his capabilities in performing Flt Nav duties. If successful, the organization could revert him back to his parent branch and original ac, thereby avoiding attrition of a valuable human resource. This case demonstrates that Adie’s tonic pupil is not always a disabling condition for military flying. Nevertheless, it has to be analyzed on a case to case basis. Aeromedical disposal of a potentially disqualifying case, having no reference in the available aeromedical guidelines.