Relationship between Serum Homocysteine Levels and Manganese Superoxide Dismutase (MnSOD) on Retinal Nerve Fiber Layer (RNFL) Thickness in Diabetic Retinopathy and Non-Diabetic Retinopathy Patients: Oral Presentation - Observational Study - Resident (The Indonesian Ophthalmologists Association (IOA, Perhimpunan Dokter Spesialis Mata Indonesia (Perdami)), 2023)