Pupillary Dysfunction in Type 2 Diabetes Mellitus to Refine the Early Diagnosis of Diabetic Autonomic Neuropathy

Abstract

Diabetic autonomic neuropathy (DAN) is one of the most disabling complications of diabetes mellitus. This study aimed to evaluate a special pupillary analysis for the early diagnosis of DAN by investigating pupil responsiveness under different conditions. Images of the pupils of 40 type 2 diabetic patients, who were divided into two (subclinical and nonproliferative diabetic retinopathy [NPDR]) groups using the results of fundus fluorescein angiography, and 20 healthy subjects were taken under mesopic, photopic, and pharmacologically dilated conditions. The pupil diameters, constriction ratio (CR), and dilation ratio (DR) were computed and calculated from the images. The mean mesopic pupil diameters (D1) of the control group, the subclinical group, and the NPDR group were 6.02 ± 0.48, 5.87 ± 0.99, and 4.95 ± 1.12 mm, respectively. The mean photopic pupil diameters (D2) were 3.40 ± 0.33, 3.37 ± 0.31, and 3.25 ± 0.47 mm, respectively. The mean pharmacologically dilated pupil diameters (D3) were 7.37 ± 0.59, 6.91 ± 1.00, and 5.49 ± 1.24 mm, respectively. The mean CR of the three groups were 0.43 ± 0.07, 0.41 ± 0.10, and 0.32 ± 0.14, respectively, and the mean DR were 0.23 ± 0.08, 0.19 ± 0.13, and 0.11 ± 0.05, respectively. There were statistically significant differences between the three groups with regard to the data of dark-adapted pupil diameter, dilated pupil diameter, CR, and DR ( p < 0.05). Autonomic pupillary dysfunction occurs early in type 2 diabetic patients. Abnormal pupil responses might be due to a dysfunction of pupillary nerve fibers. In addition, myogenic abnormalities are a causative factor to produce small D1 and DR. Pupillary diameters under mesopic and pharmacologically dilated conditions and the CR and DR of the pupillary function can be reliable parameters to evaluate autonomic neuropathy in type 2 diabetes mellitus patients.

The post‐illumination pupil response of melanopsin‐expressing intrinsically photosensitive retinal ganglion cells in diabetes

“…Studies indicate impaired pupil dynamics such as reduced baseline pupil diameter and re‐dilation amplitude occur owing to dysfunction in the autonomic innervation of the pupil in diabetics (Yang et al. 2006; Ferrari et al.…”

“…Pupillometric studies in patients with diabetes with and without diabetic retinopathy indicate dysfunction in autonomic pupil innervation (Yang et al. 2006; Ferrari et al.…”

<p>Dynamic Pupillometry in Type 2 Diabetes: Pupillary Autonomic Dysfunction and the Severity of Diabetic Retinopathy</p>

“…13 In diabetes, impairment in sympathetic and/or parasympathetic arms of the PLR have been observed. [14][15][16][17][18][19][20][21] Since the development of dynamic pupillometry 22,23 , recent advances have enabled objective and repeatable assessments of pupillary function, including dynamic responses such as latency, constriction speed, and redilation speed. However, while studies examining pupillometry measures have included some participants with diabetes, 13,21,[24][25][26][27][28] only a few have been carried out on sample populations with different stages of diabetic retinopathy.…”

Association of pupil responses with severity of erectile dysfunction in diabetes mellitus

“…[1] Diabetic autonomic neuropathy (DAN) is associated with increased mortality and morbidity in patients with DM, and it affects the cardiovascular, gastrointestinal, and genitourinary systems as well as the eye. [234] Pupil functions are under the control of the autonomic nervous system, and, in the literature, DAN has been reported to be associated with abnormal pupil responses. [45]…”