Abstract
Purpose:
To study the interrelationship of biometric indicators, refraction and intraocular pressure and blood glucose levels and glycated hemoglobin (HbA1c) in patients with Diabetes Mellitus type 2 (DM2) using insulin in subcompensation phase.
Methods:
The sample consisted of 32 patients (64 eyes): 84.4 % females and 15.6 % males) with DM2 without severe complications and concomitant eye pathology at the age of 60.4 ± 5.3 years. Ophthalmologic monitoring lasted for 3 years and insulin treatment was 6 years. Biometric indicators: anterior chamber depth (ACD), lens thickness (lens), axial length (AL) were evaluated by ultrasound biometry A-mode scan, the thicker central optical zone (TCOZ) of cornea were performed by pachymetry. Visometry, biomicroscopy, ophthalmoscopy, pneumotonometry (for Po), autorefractometry (ARM) were also conducted.
Results:
Evaluating biometric indicators of blood glucose levels, we found that they are linked to each other. The frequency of significant association was 2 times higher with HbA1c than with glucose. Analysis showed a reliable negative relation between HbA1c, AL and ACD (Spearman R (Rs) from 0.19 to 0.30, p <0.05). At the same time, the higher HbA1c was accompanied by improved performance of TCOZ (Rs = 0.19, p<0.05). For refraction, in all cases, there was a significant positive correlation between the level of HbA1c and data of ARM (sph, cyl, ax). Myopia exhibited growth (from 42% to 55%) and hyperopia decreased (from 40.29% to 24.13%) (Yates corrected χ2 p = 0.19). A significant positive correlation was found between HbA1c and IOP (Rs 0.25 to 0.35, p <0.05). There was no significant reduction of vis OU with HbA1c, but it was found with glucose (Rs 0.23-0.28). IOP and biometric indicators and vis were negatively correlated (Rs from 0.19 to 0.23, p <0.05). However, IOP and TCOZ were positively associated (Rs = 0.72, p <0.05).
Conclusions:
HbA1c was found to be more sensitive parameter than blood glucose, but not all biometric indicators, refraction and IOP reacted to them uniformly. Increasing of HbA1c and blood glucose lead to thickening of the TCOZ of cornea, reducing the depth of ACD and increased IOP; all eye tissues become more hydrophilic that results in decreasing of vis and appearing of myopia. Thus, in DM2 with using insulin, in subcompensation phase, the identified changes are complex and determined by glycemia.
Keywords: 499 diabetic retinopathy •
459 clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology •
498 diabetes