What was the medical field like during the Islamic age?

Pace /u/WARitter, I'm going to assume you mean during Islamic [Golden] age, broadly defined.

By "the medical field" I think you can plausibly mean two things. One is: "how advanced was the state-of-the-art in medicine?" and the Second is: "what was medical treatment generally during this period, either generally or in a best-case scenario?".

I'm much more familiar and capable of answering the former question. The answer to which is that some of these Islamic writings on Medicine during the Golden Age, such as Ibn Sina's (Avicenna) Book of Healing and Canon of Medicine remained medical textbooks, including in the west, until about the 18th century.

Ibn Sina wrote a brief autobiography which is extraordinary both for his obvious genius, but also for his attitude towards his respective fields of inquiry, starting with basic philosophical precepts:

Then Abū-ʿAbdallāh an-Nātilī,10who claimed to be a philosopher, came to Buḫārā. My father had him stay in our house, and he occupied himself 25 with my education. Before his arrival, I used to occupy myself with jurisprudence, attending frequently Ismāʿīl az-Zāhid11 about it. I was one of the most skillful questioners, having become familiar with the methods of posingquestions and waysf of raising objections to a respondent in the manner Customary with these people.12 Then I began to study the Eisagoge with anNātilī, and when he mentioned to me the definition of “genus,” viz., “what is predicated of many things differing in species, in answer to [the question] ‘What is it?’,”13 I surprised himg in Verifying this definition with something whose like had never been heard. 26 14 He was extremely amazed at me and cautioned my father that I should occupy myself with nothing else but Philosophy. Whatever problem he posed I conceptualized15 it better then he until I finished [in this fashion] a literal16 reading of Logic with him; as for its minute implications, though, he had no notion of them. Then I began to study the books [of the Organon] by myself and consult the commentaries until I had mastered Logic.

Moving on to Medicine, emphasis my own:

Next I desired [to learn] medicine and I read the books that have been written on this subject. Medicine is not one of the difficult sciences, and therefore I excelled in it in a very short time, to the point that distinguished physicians began to study medicine with me.20 I cared for the sick, and there opened up to me indescribable possibilities of therapy which can only be acquired through experience.21 At the same time I was also occupied with jurisprudence and would engage in legal disputations, being now sixteen years of age.

So though he would not publish his most famous medical works until he was in his 40s, this man who was at the state-of-the-art of medicine for about the next 700 years described the field as "not one of the difficult sciences" and had mastered it by the time he was 16.

We are talking about one of the greatest polymath geniuses of all time, so we shouldn't rule out that he was just a Doogie Howser, M.D.-esque precocious figure-- in fact it seems like he almost certainly was.

But by his own assessment there just simply wasn't as much to the medical field, in relative terms, as there was to logic or philosophy.

In more specialist terms and in terms of advancements, there were great advancements in the understanding of optics and ophthalmology. It's not something I've looked into in any great detail but it strikes me that medieval Islamic ophthalmology was relatively advanced in a best-case scenario in medieval Islamdom.

In terms of actual practices and outcomes in a general sense I'm afraid I'm not familiar enough with medieval Islamic medicine and sort of wider medical infrastructure and practices to comment. My suspicion would be that your access to the kind of "advanced" treatments mentioned in that ophthalmological article would have been extremely restricted in availability, and of course like all pre-modern medical practices before the discovery of germ theory and modern psychiatry and so on there were whole classes of disease and suffering the "treatments" of which, for centuries and even millenia, simply had no bearing on what the actual causes and effective treatments of such a disease might be.

edit: Mentioned emphasis, forgot to emphasize with the bolded text I intended. edit 2: my quote from Ibn Sina's biography are as translated in Avicenna and the Aristotelian Tradition by Dimitri Gutas