Retina-Vitreous
2010 , Vol 18 , Num 2
Evaluation of the Effect of Diabetes Mellitus Type 1 and its Metabolic Control on Retinal Nerve Fiber Layer Thickness
1Denizli Devlet Hastanesi, Göz Hastalıkları, Denizli, Uz. Dr.2Selçuk Üniversitesi Meram Tıp Fakültesi, Göz Hastalıkları, Konya, Yrd. Doç. Dr.
3Dicle Üniversitesi Tıp Fakültesi, Göz Hastalıkları, Diyarbakır, Yrd. Doç. Dr.
4Selçuk Üniversitesi Meram Tıp Fakültesi, Göz Hastalıkları, Konya, Prof. Dr. Purpose: To evaluate the retinal nerve fiber layer (RNFL) thickness changes in type 1 Diabetes Mellitus (DM) patients without diabetic retinopathy (DR) and the effect of blood glucose regulation .
Materials and Methods: The RNFL thickness measured by optical coherens tomography (OCT) of type 1 DM patients without DR according to ophthalmological examination (n=98) are compared with age-sex matched healthy subjects (n=49) . Fasting blood glucose and HbA1c levels measured via analysis of venous blood samples obtained after 12 hours of starvation period are evaluated for the assessment of the metabolic regulation.
Results: The mean RNFL thickness was 100.00±11.93 m in diabetic patients and 103.79±6.45 m in the control group, however this difference was not statistically significant. The comparison of RNFL thickness in superior, nasal, inferior and temporal quadrants revealed also no statistically significant change. The mean duration of DM was 60.76±50.41 months and analysis according to duration demonstrated no statistically significant difference of RNFL thickness among patients with duration of DM for 1-60 months, 61-120 months and those with duration of DM for >120 months (p>0.05). The mean fasting blood glucose was 237.46±119.22 mg/dl and the mean HbA1c was 8.77±1.94%. The HbA1c levels showed a negative correlation with RNFL thickness (koeff= - 0.49 p<0.001)
Conclusion: The RNFL thickness did not show a statistically significant difference between healthy subjects and patients with type 1 DM without DR. However the negative correlation with HbA1c suggests that poor metabolic control may cause a progressive defect in RNFL. Keywords : Type 1 Diabetes Mellitus, optical coherence tomography, retinal nerve fiber layer thickness, blood glucose regulation