Abstract
Purpose:
To investigate the influence of cyst size on response to combination therapy of a single intravitreal injection of bevacizumab (Avastin ®) followed by focal-grid laser treatment in patients with macular edema (ME).
Methods:
A retrospective review of 14 patients with 18 eyes who received a single intravitreal injection of bevacizumab (Avastin ®) (1.25mg/0.05mL) followed by focal-grid laser treatment one to two weeks post-injection was conducted. The built-in caliper tool on the Ophthalmic Technologies Inc. OCT/SLO Scanner (Toronto, Canada) was used to measure cysts pre-injection and post-laser. The largest pre-injection cyst present in each eye, by anterior-posterior diameter (APD), was categorized into three groups of cyst APD: small (0-180µm), intermediate (180-300µm), and large (300µm and greater). The cysts were then evaluated for percent change in APD post-combination therapy. Mean pre-injection and post-laser OCT imaging interval time was 2.7 months (0.9 to 8.9 months).
Results:
The etiology of ME was diabetic in all eyes but 2, which were secondary to retinal vascular occlusive disease. Six eyes were grouped into the small category, 6 into the intermediate, and 6 into the large category. Eyes in the small category had a mean APD of 140 µm pre-injection and 20 µm post-laser. These eyes demonstrated a 90% mean reduction (71-100%) in APD. Eyes in the intermediate category had a mean APD of 220 µm both pre-injection and post-laser. Intermediate category eyes had a mean change of 0% (both reduction of up to 23% and increase of up to 24%). Finally, eyes in the large category had a mean APD of 360 µm pre-injection and 170 µm post-laser. Eyes in this category had a 55% mean decrease (31-77%) in APD.
Conclusions:
Cyst APD pre-combination therapy does not correlate in a linear fashion to post-combination therapy APD. All eyes with larger cyst APDs responded and had a significant mean decrease in APD as compared with the intermediate group. The best response to treatment was in the smallest cyst category. These findings suggest that, although smaller cysts may have a better prognosis, larger cyst size does not predict a poor potential response to therapy. Further studies are warranted.
Keywords: 585 macula/fovea •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
561 injection