Comparison of optic disc damages and fluorescein filling defect of the disc between low tension and primary open angle glaucoma

The neuroretinal rim area (NRA), the cup area and the ratio of absolute fluorescein filling defect of the disc were measured in 23 cases of low tension glaucoma (LTG) and 25 cases of primary open angle glaucoma (POAG) with fluorescein angiography and computerized image analysis. The results showed that the inferior and temporal quarters of NRA in eyes of LTG were significantly smaller than in eyes of POAG, while the ratio of absolute fluorescein filling defect of the disc in LTG was larger than in POAG, and the cup of LTG was larger than that of POAG, indicating that there might be different mechanisms of optic disc damages in the two types of glaucoma.