Brief Answer:
This looks like eyelid problem.

Detailed Answer:
Hello
Welcome to Health care Magic

I am Dr Dadapeer K an ophthalmologist and I answer health problems related to eye.

It seems from the history that you are having problem of left eye looking smaller than right eye.
Since the vision is normal and equal in both the eyes pathological problem in unlikely.
This can be because of problem in the eyelids with eyelid on left side covering more compared to right eye.

If you can send the photo of the two eyes I can confirm the diagnosis for you.

Hope I have answered your question and the information is helpful to you.

Thank you

---

Brief Answer:
It is ptosis of upper eyelid and requires surgery.

Detailed Answer:
Hello
Welcome to Health care Magic

Thank you for the follow up query.

I went through the photo which you have sent along with the question.
In left eye the upper eye lid is covering more of the cornea because of down ward displacement. This is called as ptosis.
The common causes for ptosis are congenital which is present from birth and acquired which is acquired later in life.
Congenital ptosis is present from birth and have a look at your childhood photos and if they also show similar finding with left eye being appearing smaller it confirms it.
The acquired causes are problems affecting the nerves which supply the muscles of the upper eyelid and requires evaluation.

In your case ptosis is obvious and it is of moderate degree, hence treatment in the form of surgical correction is required.
If it is acquired one it requires evaluation to find out the underlying cause and treatment of the cause. In acquired causes surgery is not done in the initial stage and it is reserved for cases which are not responding to treatment of the underlying cause.

Hence to conclude you are having ptosis of left upper eyelid and this requires treatment by surgery for correction.


Thank you
with regards

---