AIM: To observe the changes of ocular physiological and functional parameters and the recovery time after close eye use in young people.

METHODS: A prospective study. A total of 69 patients(138 eyes)who underwent medical optometry in our hospital from December 2019 to June 2020 were randomly selected. According to the results of subjective optometry, they were divided into the emmetropia group(+0.75D≤ spherical equivalent ≤-0.50D, with 36 eyes of 18 cases), the low-degree myopia group(-0.75D≤spherical equivalent ≤-3.00D,with 50 eyes of 25 cases)and moderate myopia group(-3.25D ≤ spherical equivalent ≤-6.00D, with 52 eyes of 26 cases). All subjects overlooked for 20min after reading at a close distance for 20min. The physiological parameters \〖anterior chamber depth(ACD), axial length(AL)\〗 and functional parameters \〖positive relative accommodation(PRA), cross cylinder(BCC)\〗 of the eyes were measured before close visual work, 20min after close visual work, and 5, 10, 15, and 20min after overlook, respectively. The time to reach the pole and the recovery time of each parameter were analyzed.

RESULTS: After close visual work, the AL became longer, the ACD became shallower, and the absolute value of PRA became larger. There was no significant change in BCC. AL of 75%(52/69)of subjects reached the pole after 20min of close visual work, and ACD of 87%(60/69)of subjects reached the pole after 5min of overlooking. In 96%(66/69)of the subjects, PRA reached the pole after 20min of close visual work, and the parameters above gradually returned to the initial state after 10min of overlooking.

CONCLUSION: The ocular parameters changed after close visual work, of which the AL became longer, the ACD became shallower, and the absolute value of PRA increased. However, all of them gradually retreated during the process of overlooking, and all the parameters needed more than 10min to recover to the initial state.