Evaluation of Static Pupillary Parameters in Pediatric Patients with Vitamin B12 Deficiency

Abstract

Background: Automatic pupillometry device enables important information about pupillary function. Neurological manifestations such as  autonomic dysfunction and ophthalmological disorders are observed in vitamin B12 deficiency (VB12D). 

Aim: To assess the static  pupillary functions using a pupillometry device in pediatric patients with VB12D. 

Methods: The study included 40 children with VB12D and  40 healthy children in the control group. The measurements were made with an automated pupillometry under static conditions.  The static measurements were performed at scotopic, mesopic, and photopic light intensities. The differences between the patient and  control groups were analyzed with static measurements. 

Results: Pupillary diameters of the patient and control groups under scotopic, mesopic, and photopic conditions were observed and there was a statistically significant difference under the mesopic and photopic  conditions. Under mesopic conditions: The mean pupil diameter was found to be 5.92 ± 0.69 mm in the VB12D group and 5.18 ± 0.91 mm  in the control group (P = 0.003). Under photopic conditions, the mean pupil diameter was found to be 5.13 ± 0.77 mm in the VB12D group  and 4.53 ± 0.96 mm in the control group (P = 0.001). Under scotopic conditions, the mean pupil diameter was 6.46 ± 0.68 mm in the VB12D group and 6.37 ± 0.93 mm in the control group. There was no statistically significant difference between the patient and control groups in  the measurements under scotopic conditions (P = 0.63). 

Conclusion: Pediatric patients with VB12D have significantly larger pupil  diameters in photopic and mesopic conditions than healthy children. The results suggest that there is an autonomic system dysfunction  in children with VB12D, especially when the parasympathetic system is negatively affected. Pupillary contraction is reduced in children  with VB12D. Decreased pupillary myosis function is observed. Pupillary size is larger in vitamin B12‑deficient children under photopic and  mesopic conditions.