From Brotato Wiki
Eyes Surgery reduces the time between each tick of burning damage by 10%, or 0.1 second for each Eyes Surgery you have. This means that targets with the burn debuff will take damage every 0.9/0.8/0.7 second. This leads to a 11%/25%/43% increase in the damage per second done by the burn effect.
However the total amount of ticks doesn't increase. So if the burn debuff deals 10x3 damage, it will still only deal 30 damage in total, but it will happen faster.
Since multiple burn debuffs doesn't stack, but instead refreshes the duration of the burn, this might not be an issue.