Purpose: To evaluate functional and structural outcomes after application of a single intravitreal dose of faricimab in patients with chronic retinal diseases. Methods: In this observational, longitudinal, prospective study, best-corrected visual acuity (BCVA) and central macular thickness (CMT) were evaluated before and 4, 8, 12, and 16 weeks after a single dose of intravitreal faricimab. Results: A total of 49 eyes of 41 patients were included, of which 28 were treatment-naive eyes (had not previously received intravitreal therapy) and 21 were eyes in which a switch from a previous antiangiogenic agent was indicated. The main diagnoses were diabetic macular edema in 63.3% (31 eyes) and age-related macular degeneration in 24.5% (12 eyes). Ten eyes (20.4%) required additional antiangiogenic injections due to worsening or only partial improvement in CMT, whereas ~58% of eyes completing follow-up did not require further treatment and maintained anatomic improvement on optical coherence tomography throughout the study period. At 4 weeks after initial injection, CMT was reduced a mean 117.5 µm. Statistically significant decreases were maintained over 8, 12, and 16 weeks. In treatment-naive eyes, initial mean reduction in CMT was 119.7 µm, with sustained decreases at all time points, while in the treatment-switch group, initial mean reduction in CMT was 114.6 µm, with sustained decreases at weeks 4 and 8, but not at weeks 12 and 16. In the general sample, 53.1% to 61.0% of eyes demonstrated clinically modest improvements in BCVA, equivalent to 1 to 2 Early Treatment Diabetic Retinopathy Study lines of vision, but visual changes were not statistically significant. Conclusions: Clinically meaningful reductions in CMT were observed and sustained over the 16-week follow-up after a single intravitreal faricimab injection. Notably, a substantial proportion of eyes did not require additional antiangiogenic treatment during follow-up, suggesting that mandatory loading doses may not be universally required to achieve short-term anatomic benefit in selected patients. However, functional gains were modest and did not reach statistical significance, underscoring that anatomic improvement does not necessarily translate into meaningful visual recovery. These findings highlight the importance of individualized dosing strategies in real-world clinical practice and suggest potential implications for reducing treatment burden, costs, and barriers to access in eligible patients.