As a pediatric surgeon,i made a short search about the Central Serous Retinopathy,there is no evident relation between freediving and CSR.
It has been said that it is common with stress.esp it was frequent with type A people and also in airline pilots.Maybe sudden pressure changes can be the cause but you know it was the opposite (neg. pressure)in flying rather than diving.
The prognosis for CSR is mostly wonderful.Over 90% of patients reach 20/30 vision or even better in 6 months. Hope you recover soon with no recurrence Doron, take care...