**3. Conclusions**

Much research still remains to be conducted on the retina in both animal models and ALS patients. First, further research should aim to describe the different changes in the retina that occur in all pathogenic mechanisms of the disease. Second, there are several models with different genetic mutations that should also be analyzed. In addition, both the retinal and the choroid changes produced at different times in the evolution of the disease should be studied. It is known that ALS is a heterogeneous disease, with different forms of onset, development, and progression, which may potentially exhibit differences in the retina, as observed in the CNS.

The main findings found in the retina in ALS are summarized in **Figure 1** and **Table 1**.

In conclusion, multiple studies have confirmed that the retina is affected in ALS, mainly in the inner layers, and it could serve as a biomarker in this pathology. These retinal changes can be detected by noninvasive retinal imaging techniques to help in the diagnosis and monitoring of ALS disease. In addition, the retina could be used to evaluate the efficacy of different therapies in ALS in a noninvasive way.
