The lifespan is an important factor that determines the current If the current is too high, the temperature will rise. Then you need to consider the junction temperature and the thermal resistance between the junction and the pad. If the current increases and the heat cannot be dissipated efficiently, the lifespan of the LED will decrease. Besides, if the temperature turns too high, it will also affect the light the LED emits. Other factors that affect the current may include the size of the chip, the bulk resistance of the chip, the resistance of surface-extended electrodes, etc.
More reading: LED PCB Design Guide: Challenges & Considerations
