Abstract
Purpose::
Employing the novel combined OCT-SLO system (o.t.i. - Ophthalmic Technologies Inc. Toronto, Canada) we assessed patients with cystoid macular edema after intravitreal therapy. We herein demonstrate measurement options the device has to offer for quantifying therapeutic progress.
Methods::
The OCT-SLO allows for retinal thickness measurements by stacking of 200 transversely obtained C-scan OCTs. We calculate central foveal thickness change and net change in retinal thickness in an area of 20°x20°. Imaging with the OCT-SLO moreover offers 3-D imaging of cystoid cavities impairing central vision. Changes in cystoid volume can be quantified by measuring cystoid diameters in three dimensions. Scans and measurements were performed on 10 patients with age-related macular degeneration (ARMD), 8 with diabetic macular edema (DME), and another 5 with signs of central or branch retinal vein occlusion (RVO). All patients were treated with one intravitreal injection of either Ranibizumab (lucentis®), Bevacizumab (avastin®), or Triamcinolone.
Results::
In ARMD patients C-scan OCT mapping revealed a mean reduction in central foveal thickness of 157 ± 178 microns (p < .05) and a mean net change of -53.2 ± 100 microns in overall retinal thickness in the 20°x20° area. We detected a mean reduction in central cystoid cavity volume of .085 ± .231 µL (p < .05). DME patients: mean reduction of central retinal thickness was 107 ± 114 microns (p < .05), mean net change was -56.9 ± 24 microns in overall retinal thickness. We detected a mean reduction in central cystoid cavity volume of .028 ± .03 µL (p < .05). RVO patients: we detected a mean reduction of central retinal thickness of 225 ± 323 microns (p > .05) and a mean net change of -143 ± 195 microns in overall retinal thickness. Mean reduction in central cystoid cavity volume was calculated to be .083 ± .095 µL (p > .05).
Conclusions::
The novel OCT-SLO combination proves to be a concise and comprehensive tool for quantitative evaluation of the therapeutic progress and morphometric changes within the retina following intravitreal injections.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • macula/fovea • injection