Abstract
Purpose: :
MP-1 is used to evaluate the fixation patterns and the retinal sensitivity in patients who clinically had or didn’t have a significant macular edema. The aim of this study has been the assessment of the specificity and the sensitivity so to quantify the fixation stability by the BCEA ( bivariate contour ellipse area) compared to the percentage of the fixation points in patients with a widespread macular edema.
Methods: :
32 patients suffering from diabetes were involved in the study. A total of 64 eyes were examined. All the patients underwent the following tests: visual acuity, reading speed, fixation test, MP-1 microperimetry (using both traditional and BCEA techniques) and OCT.The main resulted measures have been the fixation stability and position and the mean retinal sensitivities within the central 2°and 4° areas. Age, duration of diabetes, hemoglobin A1c levels, duration of symptoms and cystoids macular changes have been documented. Patients were analyzed as to the position of fixation (central or eccentric) as to the stability of fixation (stable or unstable). Statistical analyses included the independent sample t- test and the linear regression test.
Results: :
Out of 32 diabetic examined patients, 14 (43%)(mean 55,3 years old, range 44-77) had untreated macular edema, while 18 patients (57%)(mean 52,1 years old, range 45-75), who didn’t have any macular edema, were excluded. Out of 28 examined eyes, all of them had eccentric fixation. In the sample, the mean central 2° fixation ± SD was 75.88 ± 20.90, the mean central 4° fixation ± SD was 90.88 ± 10.03, the mean BCEA (95) ± SD was 12.75 ± 8.60 and the mean BCEA (99) ± SD was 22,79 ± 15.37. Log MAR BCVA has ranged from 0,15 to 0,09 (average ± SD 0.4 ± 0.35). The mean OCT foveal thickness ± SD was 288.45 ± 42.63 (range 240-500 m). The duration of the symptoms was significantly longer, the HbA1c levels were higher in patients with eccentric or unstable fixation and the prevalence of cystoids macular changes was significantly higher (p < 0.001). From the mutual relation between the visual acuity and the percentage fixation in the 2° and 4° central areas first and the visual acuity and the BCEA technique after, it has been evident that there has been a statistically significant correlation among these last ones.
Conclusions: :
In patients with untreated macular edema, the BCEA technique of quantifying the fixation stability calculating the surface area is more specified and sensitive compared to the traditional method to quantify the fixation stability by the percentage of the fixation points in 2° and 4° central areas.
Keywords: microscopy: fixation processing • diabetic retinopathy • edema