The arrangement is quite simple. Under the terms of the DFA, if...

The arrangement is quite simple.
Under the terms of the DFA, if sozinibercept is approved in a major market, Opthea will make a milestone
payment after regulatory approval and then six subsequent annual fixed success payments and variable
success payments of 7% of net sales, with cumulative payments capped at four times the amount funded
to Opthea.

Therefore, whatever they put in, in this case $170m USD, they stand to gain up to 4x that amount.
The amount depends on multiple milestones, whenever Opthea succeeds.
Look at it this way, 4x is clean for the VC; no risk of dilutions, no risk of corporate inefficiencies.
From Opthea's perspective, this funding is good because it is non-dilutive (imagine raising that amount with the share price) and the repayments are contingent on success.

I like the arrangement.