Abstract
Purpose :
Although neovascular age-related macular degeneration (nAMD) can be treated effectively with anti-VEGF drugs, there is still uncertainty regarding the management of nAMD that is complicated by large sub-macular hemorrhage. In order to compare different interventions, the size of the hemorrhage must be accurately defined. We hypothesise that the area of the hemorrhage is a more reliable measurement than the thickness.
Methods :
Ten observers (six consultant retinal specialists and four senior trainees) reviewed nine sub-macular hemorrhages, using Topcon 2000 OCT images and software. They independently measured the thickness of the sub-foveal hemorrhage from Bruch’s membrane to the internal limiting membrane, using the calliper tool on the B-scan image that passed through the fovea. They also measured the area of the hemorrhage in the fundus image, using the area function of the image analysis tool. The intra-class correlation coefficient was then calculated for the ten observations of each of the nine sub-macular hemorrhages.
Results :
The intraclass correlation coefficient for hemorrhage thickness was 0.673 (95% c.i. 0.448 to 0.889). The correlation coefficient for area was 0.991 (95% c.i. 0.978 to 0.997). There is significantly more intra-observer variation when measuring the thickness of a sub-retinal hemorrhage than when the area is measured.
Conclusions :
We have previously demonstrated that the area of the blood is a reliable indicator of the visual prognosis following pneumatic displacement with pars plana vitrectomy, sub-retinal tPA, and gas for large sub-macular hemorrhages. It is likely that thickness of the hemorrhage also influences post-operative vision. However, in large sub-macular hemorrhages, the blood may obscure Bruch’s membrane, making it difficult to obtain reliable measurements. This study confirms that measurement of the area of a sub-retinal hemorrhage is a more reliable method of estimating the size of the hemorrhage than measuring the thickness. We recommend that measurement of hemorrhage area is included in future studies of interventions for sub-macular hemorhage secondary to nAMD.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.