Based on the fatwaa's I have seen on Islamqa. Drawing the eye itself is not haram because it is not an animate being; something that cannot be counted as living therefore, it is a inanimate object and it cannot be counted as an image.
It is drawing a creation that resembles the creation of Allah itself is haram which would make you an image maker.
" It seems that images which do not have complete features, which do not have a nose or eyes, are not included under the heading of haraam images, and the ones who make them are not included in this warning, because they cannot truly be said to be images, and these images do not imply imitating the creation of Allaah. "
"Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allaah have mercy on him) said: With regard to dolls made of cloth, where the image does not have clear features, even though it has limbs, a head and neck, but there are no eyes or nose, there is nothing wrong with that, because this is not imitating the creation of Allaah. End quote. "
"Everyone who makes something that imitates the creation of Allaah is included in this hadeeth"
Here is the key one - "But as I said, if the image is not clear and if it does not have eyes or a nose or mouth or fingers, then it is not a complete image, and is not imitating the creation of Allaah, may He be glorified and exalted. End quote. "
The Prophet (peace and blessings of Allaah be upon him) said: “The image is the head; if the head is cut off, there is no image.” Narrated by al-Ismaa’eeli in his Mu’jam from the hadeeth of Ibn ‘Abbaas and classed as saheeh by al-Albaani in al-Silsilah al-Saheehah no. 1921 and in Saheeh al-Jaami’ no. 3864.
2 – The majority of fuqaha’ are of the view that if something is cut off from an image without which it could no longer live, then it is not a haraam image. For a detailed discussion of this issue and the views of other madhhabs, see Ahkaam al-Tasweer fi’l-Fiqh al-Islami, pp. 224-240. "
https://islamqa.info/en/39806
https://islamqa.info/en/72915
https://islamqa.info/en/102277
https://islamqa.info/en/110504
https://islamqa.info/en/110504
https://islamqa.info/en/129446
This is the most puzzling one because if I draw a cartoon head but if the head is cut off than it is halal? I too need to understand this ruling - "