Abstract
Purpose: :
to investigate the role of frequency doubling perimetry (Humphrey Matrix; Carl Zeiss Meditec Inc., Dublin, CA, USA) in the long term follow up in subjects with type 1 diabetes mellitus (DM1) without any signs of retinal vasculopathy, and to investigate the relationship between both functional and structural retinal parameters and metabolic control.
Methods: :
consecutive subjects with DM1, with no sign of retinal vasculopathy at baseline, have been followed for long term in this prospective cross-sectional clinical study. Functional testing included Humphrey Matrix perimetry (30-2 threshold program) and white-on-white Humphrey visual field perimetry (HFA, 30-2 SITA standard), while retinal nerve fibre layer (RNFL) thickness was measured by scanning laser polarimetry with variable corneal birefringence compensator (GDx VCC).
Results: :
data from 19 eyes of 19 subjects with DM1 (age 39,5±9,2; 10 males/9 females) were analyzed. Mean follow up time was 59,2±5,4 months (range 49-65). Mean diabetes duration was 17,4±13 years. Mean HbA1c was 7,42±1,22%. 10/19 patients used insulin microinfusor. Only one patient showed a progression to non proliferative diabetic retinopathy during the follow up. Similar values were found between baseline and the end of follow up both for HFA mean deviation (MD: -2,20±3,44 vs -1,63±2,47; p=0,14) and pattern standard mean deviation (PSD: 2,50±1,71 vs 2,28±1,36; p=0,31). Matrix MD was found to be similar between baseline and the end of follow up (-1,06±3,62 vs -1,24±2,99; p=0,65). A statistically significant difference was found for Matrix PSD between baseline and the end of follow up (2.76±0.59 vs 3.1±0.68; p= 0.0078). Morphological parameters were not changed during follow up. A significant relationship was found between HbA1c levels and changes from baseline of Matrix PSD (R2 0,29, p=0.02).
Conclusions: :
the localized reduction of retinal sensitivity, as measured by Matrix, seem to be the only parameter that showed a significant change during long term follow up in our population of DM1 patients.
Keywords: perimetry • diabetes • nerve fiber layer