The goal of this clinical trial is to evaluate the feasibility and safety of pterygopalatine ganglion (PPG) stimulation in adults with geographic atrophy (GA) secondary to age-related macular degeneration (AMD).

The main questions it aims to answer are:

Is PPG stimulation feasible to implement, as reflected by participant adherence to the intervention and completion of follow-up assessments? Is PPG stimulation safe, as assessed by the incidence of adverse events and clinical ophthalmic examinations? What are the preliminary effects of PPG stimulation on choroidal perfusion, retinal sensitivity, visual acuity, and the progression of GA lesion area?

Researchers will compare active PPG stimulation with sham stimulation (a procedure that mimics the intervention without delivering real stimulation) to assess feasibility and safety, while exploring potential therapeutic effects.

Participants will:

Receive active or sham PPG stimulation according to randomization over a 12-month study period Attend scheduled clinic visits for safety monitoring and multimodal ophthalmic assessments Undergo examinations including optical coherence tomography (OCT), fundus autofluorescence imaging, microperimetry, and visual acuity testing

Inclusion Criteria:

• Best-corrected visual acuity (BCVA), as measured using the Early Treatment Diabetic Retinopathy Study (ETDRS) chart, ranging from 25 to 80 letters (Snellen equivalent, 20/320 to 20/25).

• A confirmed diagnosis of geographic atrophy (GA) secondary to age-related macular degeneration (AMD), with no involvement of the foveal center. Fundus autofluorescence (FAF) imaging must demonstrate a total GA area of 2.5 to 17.5 mm² located within a 30° field centered on the fovea, with the presence of any pattern of increased autofluorescence at the junctional zone of GA. In cases of multifocal GA, at least one lesion must be ≥1.25 mm² in size.

  • If both eyes meet the eligibility criteria, the eye with the worse BCVA will be selected as the study eye. If BCVA is equal in both eyes, the right eye will be designated as the study eye.

Exclusion Criteria:

• History or evidence of submacular surgery or other treatments for AMD in the study eye, with the exception of oral vitamin and mineral supplementation.
• History of intraocular surgery within 3 months prior to screening, or the presence of ocular conditions requiring surgical intervention during the study period.
• Receipt of any periocular or intravitreal injection therapy in the study eye within 3 months prior to screening.
• History or evidence of choroidal neovascularization in either eye, or the presence of any other retinal disease that may confound the assessment of macular structure or function (e.g., diabetic retinopathy or pathologic myopia).
• Presence of severe systemic disease or any other condition deemed unsuitable for study participation.
• Inability to comply with scheduled visits or complete study procedures due to cognitive impairment or other factors, as judged by the investigator.