Eye examinations are important because body tumors often regress completely and leave no trace, but this is not true for ocular tumors. A turtle with body tumors but no eye tumors is almost certainly a regression case. In our 245 turtles with FP, just eight were never seen with eye tumors. Two of these turtles were confirmed regression cases. Six of the turtles had eye anomalies consistent with regression, and all eight had body tumors that appeared to be regressing.
Eye examinations give a better understanding of an individual's FP status.
If a turtle has tumors, it is possible to determine whether they are active or retreating. If tumors are completely absent, normal eyes suggest an animal has never had the disease. Black pearls or an FP signature indicate that it has battled the disease and survived. Pre-eruptive eyes suggest a battle that's yet to be fought. This is particularly relevant in Hawaii, because honu demonstrate strong site fidelity.