Abstract
Purpose: :
To evaluate subfoveal choroidal thickness in patients with idiopathic macular telangiectasia type 2 (MacTel2) compared with normal eyes.
Methods: :
In this prospective, observational study, patients with the diagnosis of MacTel2 were enrolled in The MacTel Project at the Bascom Palmer Eye Institute. Eyes previously treated with photodynamic therapy (PDT) were excluded from this analysis. The control group was comprised of individuals with no known ocular disease. All patients in the study and control groups underwent a complete ophthalmological exam, SD-OCT imaging (Spectralis, Heidelberg), which included enhanced depth imaging, and axial length measurements (IOL master, Carl Zeiss Meditec). Patients in the study group also underwent color fundus photography, fundus autofluorescence (FAF), and fluorescein angiography (FA). Medical records were used to obtain information about current and past medical conditions and previous treatments such as PDT, intravitreal drug therapy, and focal laser. Three independent graders obtained manual subfoveal choroidal thickness measurements. Multiple linear regressions were used to compare choroidal thickness between patients and normal controls adjusting for age and axial length, and were also used to evaluate the correlations with other variables such as previous treatment.
Results: :
A total of 88 eyes of 44 patients were included in the study group. Two eyes of 2 patients were excluded from the analysis for having received previous PDT. The control group was comprised of 76 eyes of 38 normal individuals. Mean ages in the study and control groups were 64.3 (SD=9.7) years and 61.2 (SD=13) years, respectively. After correction for age and axial length, mean subfoveal choroidal thicknesses were 337 µm in the study group and 242.9 µm in the control group. The intraclass correlation coefficient between the graders was 0.99. The mean choroidal thickness in the untreated MacTel patients was 354 µm compared with 277 µm in the MacTel patients who had received previous treatment. Statistically significant differences were found between the untreated MacTel eyes and normal eyes (p < 0.001) and between untreated and treated MacTel eyes (p = 0.002). Patients with diabetes (37 eyes) had a thinner mean choroidal thickness by 51.3 µm (p=0.088) compared with patients without diabetes (49 eyes).
Conclusions: :
On average, patients with MacTel 2 were found to have thicker subfoveal choroidal thickness measurements compared with control subjects. This observation suggests that MacTel 2 affects the vasculature in the choroid as well as the retina, and may help in understanding the underlying pathophysiology of this disease.
Keywords: choroid • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)