A study of pupil cycle time (PCT) in altered state of nutrition in Indian male.

Pupil cycle time (PCT) is a simple way to measure the parasympathetic activity in the eye. This is a sensitive and specific test for the study of parasympathetic function. The cardiac parasympathetic tone is a good indicator to predict morbidity and mortality in an individual. The PCT is correlated with cardiac parasympathetic tone. In the present study we have aimed to look at the PCT in different nutritional status in human subjects. Sixty-three healthy adult male volunteers in the age group of 18–50 yrs were studied. They were divided in three groups based on their BMIs as undernourished, normal and preobese/obese. The mid-arm circumference (MAC) and waist- hip ratio (W:H) are incorporated as adjuvant to strengthen that they are divided into three different nutritional groups. The PCTs of undernourished (818±145 ms), normal control (904±63 ms) and overweight (991±106 ms) is expressed as mean and SD (P<0.001). A linear regression analysis was performed taking BMI, MAC, W:H and PCT as parameters, which shows a positive linear correlation. The results showed that the PNS activity in the eye is greatly modulated in different states of nutrition. Pupil cycle time is a simple, noninvasive investigative tool to assess and differentiate the PNS function in obese and chronic undernourished subjects.

Pupil cycle time and contrast sensitivity in type II diabetes mellitus patients: A pilot study.

Context: Pupil cycle time (PCT) has been widely used for examination of ocular diabetic autonomic neuropathy (DAN). Aims: The primary aim of this study was to evaluate the difference of contrast sensitivity according to PCT results, and the secondary aim was to determine the factors associated with PCT difference for type II diabetes patients. Settings and Design: A clinical pilot study that included a total of 60 eyes of 60 type II diabetes patients. Materials and Methods: We divided all patients into three groups according to PCT results. Group A and Group C were composed of patients who had upper one third PCT and lower one third PCT, respectively. We analyzed difference of age, diabetes duration, hypertension duration, mean best corrected visual acuity (BCVA), mean spherical equivalent (SE), HbA1C, glomerular filtration rate (GFR), stage of diabetic retinopathy, and Cardiac Autonomic Function Score (CAFS). Contrast sensitivity and decrease of visual acuity by glare were also estimated and analyzed for 28 eyes of 28 non-proliferative diabetic retinopathy (NPDR) patients. Group [NPDR] A and Group [NPDR] C were defined as those who had lower one third PCT and upper one third PCT, respectively. Statistical Analysis: Statistical analysis was done using SPSS 17.0 software. Results and Conclusions: Each group contained 20 eyes. Significant differences between Group A and Group C were observed in duration of diabetes and CAFS (P ≤ 0.001 and P <0.001, respectively). Contrast sensitivity in Group [NPDR] A was significantly more than in Group [NPDR] C at all cpds (all P ≤ 0.001). We found that PCT can influence contrast sensitivity or glare in diabetes patients and also confirmed a significant correlation of PCT with CAFS and duration of diabetes.

Pupil Cycle Time in the Diabetics

In order to evaluate the ocular autonomic dysfunction in diabetics, pupil cycle time(PCT) was assessed in 201diabetics and 33controls. PCT was significantly different between the diabetics and controls and prolonged in diabetics in regard to the severity of retinopathy(p<0.05). PCT was significantly prolonged in diabetics in regard to the diabetic peripheral neuropathy and nephropathy(p<0.05). PCT was significantly different among the diabetic groups in regard to the duration of diabetes(p<0.05). Sustainde PCT was unmeasurable in 56.7% of diabetics and in 72.3% of proliferative diabetic retinopathy compared with 28.8% of controls(p<0.05). Ocular autonomic dysfunction in diabetics correlated closely with the severity of the diabetic retinopathy, diabetic petiphetal neuropathy and nephropathy, diabetic duration.