I have read that using Latisse can cause periorbital fat atrophy- how common is this?

Factors that you can weigh in making your decision are:
1. Periorbital fat atrophy has mostly been observed with the common on-label bimatoprost uses (Latisse for lashes or Lumigan for glaucoma). It is possible that periorbital fat atrophy is less likely to occur if Latisse is applied to the eyebrow area because the skin there is thicker than that of the eyelids so less Latisse may be reaching fat. (Note use of "possible" and "may").
2. Fat atrophy caused by Latisse is appears to be reversible. If you see fat shrinkage that you find unattractive, you can stop using the Latisse and the process would be anticipated to gradually reverse. (Note use of "appears" and "anticipated").
3. We have no trials that look at the effectiveness of Latisse for deliberate or unintended fat atrophy so we have no idea how many patient experience this. We also have no idea if it always reverses.
4. My patients who are using Latisse to promote eyebrow growth do not appear to be experiencing fat atrophy; however, this is only an observation and does not carry the weight of a proper scientific trial.
I wish you luck with this.

Although Latisse can cause fat atrophy around eyes, nobody knows how common it is. It likely depends on the individual tendency to get affected in addition to how much Latisse is used, etc.

The risk for periorbital fat atrophy is very low. You can use Latisse long term, but eventually results may plateau. For regrowing the eyebrows, I recommend viviscal, prp and progesterone. I recommend getting a formal evaluation with a hair loss expert. Best, Dr. Emer