![]() Physiological anisocoria’s mechanism is unknown no pharmacological finding indicating the denervation of iris dilators and no damage to the peripheral nerves that innervate the sphincter and dilator muscles of the iris has been recorded. The prevalance of physiological anisocoria is thought to decrease in bright light. Differentiation of physiological anisocoria from an acquired cause is crucial in order to avoid unnecessary diagnostic work-up. Anisocoria in the absence of any accompanying ocular or neurological pathology is known as ‘physiological anisocoria’ and is reported to be present in 8–43.1% of the population based on the different measurement methods. Īnisocoria is a condition characterised by an unequal size of the pupils, usually defined as a 0.4 mm or more difference between the diameters. Automated infra-red pupillometry systems which are installed with infra-red illumination and a high resolution camera technology allow to examine amplitude, latency and velocity of pupil contraction as an autonomic testing tool. However, recent developments to automated infra-red pupillometry devices has allowed the control of stimulation parameters and the objective and quantitative measurement of pupil diameters and kinetic reflexes to light stimuli. Clinicians measure the pupil size under room light and near total darkness. The average pupil diameter is affected by the factors including age, sex, iris colour, retinal and optic nerve health and optical media clarity but, the most powerful determinant of pupil size is the luminous intensity of the incoming light. Measurement of pupil diameter has gained importance in recent years in order to minimise the occurrence of scotopic phenomena such as halos, glare and monocular double vision after refractive surgeries. However, parasympathetic system activity plays a more dominant role than sympathetic system during the pupil constriction phase. It has a wide dynamic range and is controlled by the antagonistic interactions of the iris sphincter and dilator muscles, innervated by the parasympathetic and sympathetic pathways of the autonomic nervous system respectively. The pupil increases the depth-of-focus of the eye optically and improves the range of clear vision. The mean contraction amplitude and contraction velocity of smaller pupils was lower when compared to fellow larger pupils of anisocoric patients. The mean velocity of anisocoric small pupils’ contraction was lower than the mean velocity of anisocoric large pupils’ contraction ( p = 0.013). The mean relative amplitude of anisocoric small pupils’ contraction was lower than the mean relative amplitudes of pupil contraction of both isocoric and anisocoric large pupils ( p = 0.021, p = 0.035, respectively). ResultsĪfter inter-ocular comparison of pupillary diameters of 195 participants with a mean age of 38.4 ± 18.9 years (range 7–78 years), six (3.1%) participants under high photopic 11 (5.6%) participants under low photopic 25 (12.8%) participants under high mesopic, and 34 (17.4%) participants under low mesopic illumination levels exhibited physiological anisocoria. The inter-ocular dynamic pupillometric parameters (amplitude, latency, duration and velocity of pupil contraction latency, duration and velocity of pupil dilation) of these patients were further analysed. ![]() ![]() ![]() ![]() After inter-ocular comparison of these data, the prevalance of physiological anisocoria was detected in four different lighting conditions. MethodsĪutomatic quantitative pupillometry system was used to measure pupillary diameters in low mesopic (0.1 cd/m 2), high mesopic (1 cd/m 2), low photopic (10 cd/m 2) and high photopic (100 cd/m 2) conditions. To evaluate static pupillometric measurements and making inter-ocular comparative analysis in healthy subjects for demonstrating the prevalance of physiological anisocoria in various lighting conditions and to compare the variations of the dynamic pupillometric measurements of the patients with physiological anisocoria. ![]()
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