The recent emergence of three-dimensional organoids and their utilization as in vitro disease models confirmed the complexities behind organ-specific functions and unravelled the importance of establishing suitable human models for various applications. Also, in light of persistent challenges associated with their use, researchers have been striving to establish more advanced structures (i.e. assembloids) that can help address the limitations presented in the current organoids.

In this review, we discuss the distinct organoid types that are available to date, with a special focus on retinal and brain organoids, and highlight their importance in disease modelling.

We refer to published research to explore the extent to which retinal and brain organoids can serve as potential alternatives to organ/cell transplants and direct our attention to the topic of photostimulation in retinal organoids. Additionally, we discuss the advantages of incorporating microfluidics and organ-on-a-chip devices for boosting retinal organoid performance. The challenges of organoids leading to the subsequent development of assembloid fusion models are also presented.

In conclusion, organoid technology has laid the foundation for generating upgraded models that not only better replicate in vivo systems but also allow for a deeper comprehension of disease pathophysiology.