The object of this study is to investigate the damage to the retinal nerve fiber layer (RNFL) and ganglion cell complex layer (GCL+) in diabetic patients without retinal microangioma as detected by fundus fluorescein angiography (FFA) and to determine the kind of nerve damage more likely to indicate early injury.

Patients with type 2 diabetes mellitus and healthy volunteers will be included in our study. Patients with retinal microangioma are excluded by FFA. The parameters around the optic disc and macular area of the above two groups are measured by optical coherence tomography (OCT), and the results will be analyzed using the SPSS 22.0 software.

Inclusion Criteria:

1. Patients with T2DM
2. Patients without microangioma

Exclusion Criteria:

1. Patients with any other ocular disease that might affect retinal nerve injury
2. Patients with optic neuropathy, age-related macular degeneration, retinal and choroidal disease, and retinal artery/vein occlusion.
3. Patients with hypertension, hematopathy, neuropathy, and other systemic diseases causing retinal nerve changes.
4. Patients with keratopathy, cataract, and vitreous hemorrhage were also excluded.