Objective
To compare and quantitatively analyse the different characteristics of multimodal imaging of geographic atrophy (GA) in age-related macular degeneration (AMD).
Methods
The study included multimodel images of 32 eyes of 27 patients with GA secondary to AMD. There were 14 males (17 eyes) and 13 females (15 eyes). The age ranged from 64 to 83 years, with the mean age of (74.4±7.6) years. All eyes were examined by color fundus photography (CFP), fundus autofluorescence (FAF), fundus fluorescein angiography (FFA) and spectral domain optical coherence tomography (OCT). Using image J software, two trained ophthalmologists, operating in masked fashion, graded the area of lesions of CFP, FAF and FFA independently and compared the sizes of GA area. OCT was performed to confirm the border of lesion when FAF difficult to be determined. The results consistency of two ophthalmologists was analyzed by Bland-Altman.
Results
The results consistency was high of two ophthalmologists, with the variation range of FFA＜FAF＜CFP. The GA area of CFP, FAF and FFA were (19.81±13.03), (21.50±13.61), (23.10±14.29) mm2. The difference of GA area between three multimodel images was statistically significant (F=0.466, P=0.629).
Conclusion
The mean size of GA measured by CFP, FAF and FFA showed no statistical difference.
Atrophic age-related macular degeneration (AMD) does not show obvious loss of visual function in the early stage, so it is not easy to be taken seriously. In the advanced stage, most of the patients suffered from macular area retinal map atrophy, which affected night vision and central vision. Drugs currently used in clinical or clinical trials to treat atrophic AMD include drugs for improving choroidal perfusion, reducing the accumulation of harmful substances, preventing oxidative stress injury, inhibiting inflammatory reactions, as well as neuroprotectants and lipid metabolism drugs. Stem cell transplantation for atrophic AMD is currently the most promising treatment. In theory, it is feasible to replace atrophic AMD with retinal photoreceptor cells and RPE cells derived from human stem cell differentiation. However, there are still many problems to be solved, such as how to improve the efficiency of directional differentiation of seed cells and how to ensure the safe and effective RPE cell transplantation and survival after transplantation. At present, several studies have found that multiple locus mutations are associated with atrophic AMD, so gene therapy also plays an important role in the development of the disease.
Geographic atrophy (GA), the late-stage of non-neovascular age-related macular degeneration, is characterized by progressive degeneration of photoreceptors, retinal pigment epithelium, and the choriocapillaris, ultimately leading to irreversible central vision loss. Advances in multimodal imaging, particularly the optical coherence tomography (OCT) based definition of complete retinal pigment epithelium and outer retinal atrophy (cRORA), have substantially improved the diagnostic consistency of GA. The recent approval of complement inhibitors, pegcetacoplan (complement C3 inhibitor) and avacincaptad pegol (complement C5 inhibitor) marks a treatment milestone, demonstrating efficacy in slowing atrophy progression. However, the efficacy of existing drugs still mainly focuses on structural endpoints, with limited protective effects on functions. This reveals the core challenge of "structural-function dissociation" in GA. In recent years, attention has been drawn to early endpoints such as incomplete retinal pigment epithelium and outer retinal atrophy transforming into cRORA; sensitive functional assessment tools such as micro-perimetry, as well as artificial intelligence-assisted OCT stratified analysis and individualized progression prediction models, have also continuously expanded the assessment and management capabilities of GA. Additionally, diverse treatment strategies such as gene therapy, stem cell transplantation, and neurotrophic protection are also being actively explored, further broadening the future intervention pathways. It is worth noting that the prevalence and clinical manifestations of GA in Asian populations are significantly different from those in Western populations, suggesting that the disease characteristics and mechanisms may have racial specificity. Currently, there is a lack of systematic local data in China, and it is urgent to establish a multicenter longitudinal cohort based on cRORA criteria, and incorporating multimodal imaging and functional assessments, to facilitate GA characterization, risk prediction, and the development of individualized intervention strategies in the Chinese population.
