[Contrast sensitivity and optic coherence tomography examinations in adolescent patients with diabetes type I preretinopathy (a pilot study)].

AIM: To evaluate the development of retinal changes in adolescent patients with diabetes type I (T1DM) with diseases duration more than 10 years, which started before 5 years of age.

METHODS: The development of the findings on the posterior pole was followed up. The retinal functions were established by means of contrast sensitivity in four space frequencies: 3 cycles/degree (c/deg) (perimacular area), 6 c/deg and 12 c/deg (macular area), and, finally, 18 c/deg (foveola). The central retinal thickness, average retinal thickness of the specified quadrant of macular area, the foveolar depth of its own, and the volume of the perimacular area (perimacular cube volume) were measured by means of optical coherent tomography (OCT).

MATERIAL: Altogether 20 patients with diabetes type I meeting the set criteria were examined, and their findings were compared with control group of healthy adolescent people. The values from the control group were used as our normative database.

RESULTS: On the retina, there were found, during the diseases course lasting in average 13.3 years, changes of the macular area, especially tortuosity of macular final capillaries and pigmentation with disappearing of foveolar reflex, which, in 20 %, were followed by sporadic hard exsudates of the retina. Difference of the decreased values in adolescent patients, comparing to the control group, was recorded in contrast sensitivity in space frequencies of 3 c/deg (p 0.047) and 12 c/deg (p 0,0497), but statistically significant was the difference in space frequencies of 6 c/deg (p 0.0001) and 18 c/deg (p 0.0001). Using the OCT, no statistically significant difference was found in the central retinal thickness, but the values of foveolar depth in patients with diabetes type I were variable (p 0.0153); in four eyes it was much deeper, and in other four of them it was much shallower. Furthermore, there was higher the average thickness of the retina (p 0.0008) and the volume of the perimacular area (perimacular cube) (p 0,0001).

CONCLUSION: The findings in eight eyes out of five patients with T1DM were evaluated as diabetic preretinopathy - pre-stage of beginning stage of diabetic retinopathy in central area of the retina from the functional and structural point of view of current pathological changes of contrast sensitivity and OCT. The findings of other three patients were rated as diabetic preretinopathy according to sporadic hard exsudates of the retina and OCT changes, but. until now, without contrast sensitivity changes. The one-year profile of glycated hemoglobin (HbA1c) was higher in patients with diabetic preretinopathy than without the eye involvement, but it was not statistically significant (p 0,0314).Key words: Contrast sensitivity (CS), Spectral Domain Optic Coherence Tomography (SD-OCT), diabetes mellitus type I (T1DM), diabetic preretinopathy (DpR), glycated hemoglobin (HbA1c).