The following is a summary and translation.
The manuscript OP had is what the detailed eye looks like according to Hunayn ibn Ishaq an influential Nestorian Christian translator, scholar, physician, and scientist.
Summary: In his manuscript, Hunayn believes that the eye is made of many parts and that not all of its parts are sight, but rather moisture similar to ice. As for the rest of the moisture that is in the eye and the layers and everything else other than that, each one of them was created for the benefit of the icy moisture aforementioned.
The icy moisture according to Hunayn is pure white, bright, round, hard to rotate, but it has a width, and it is in the middle of the eye, like a point we could imagine lying in the middle of a ball.
Hunayn sees this icy moisture as being in between two moistures, the one behind is similar to melted glass called vitreous, and the other in front is similar to egg white which he called an egg.
He then states that behind the vitreous moisture there are three layers: the first layer contains the vitreous moisture and is similar to the retina (meaning the retinal veil), and the second layer is behind the first and is similar to the placenta and is called the chorionic layer, and the third layer behind the second follows the bone and it is hard and strong, and is called the rigid membrane.
In the image displayed by OP, Hunayn mentions
and I am still a beginner with regards to the benefits of every single moisture and its cleanliness which I described in beginning of asserting its structure, its being, its flexion, and its places, and I had proceeded by informing you that the skin moisture is in the middle of the eye and that behind it is one and a third of layers, and its frame is one moisture and a third of layers $\color{red}{\text{red dot}}$.
He then states the importance of the moisture
With the help of God, we will be explaining $\color{red}{\text{the functions of the previous structures}}$, which are the three layers that we mentioned before, so we say that every member of the body must be nourished because it must be missing something through the decomposition of natural heat from within... (the rest of the text is not shown in the image but he proceeds to explain some source of nourishment in the blood.)