·AIM:To observe the application value of fundus pre-set lens examination in preoperative fundus examination and predicting postoperative best-corrected visual acuity(BCVA)of cataract.·METHODS:A total of 671 patients 874 eyes with cataract were observed and all the eyes were divided into 3 groups according to lens opacities degree:group A:grade 3 or lower;group B:grade 4;group C:grade 5.Before phacoemulsification,ocular fundus was observed respectively by direct ophthalmoscope and fundus pre-set lens(+90D).We tried to forecast the postoperative BCVA by fundus examination combining lens opacities degree and preoperative BCVA analysis.Ocular fundus and BCVA were reexamined in two weeks after phacoemulsification.Compare the detection rate of preoperative ocular fundus diseases and coincidence rate of predictive postoperative BCVA by direct ophthalmoscope and fundus pre-set lens.Pearson’s chi-square test was used in the data statistics.·RESULTS:The detection rate of preoperative ocular fundus diseases by direct ophthalmoscope:group A:96.8%(30/31);group B:69.5%(66/95);group C:35.3%(18/51),coincidence rate of predictive postoperative BCVA by direct ophthalmoscope:group A:94.8%(163/172);group B:87.4%(416/476);group C:60.6%(137/226).The detection rate of preoperative ocular fundus diseases by fundus pre-set lens:group A:100%(31/31);group B:93.7%(89/95);group C:84.3%(43/51),coincidence rate of predictive postoperative BCVA by fundus pre-set lens:group A:95.9%(165/172);group B:92.0%(438/476);group C:76.1%(172/226).The detection rate of preoperative ocular fundus diseases and coincidence rate of predictive postoperative BCVA by fundus pre-set lens were significantly higher than by direct ophthalmoscope in group B and group C.The total detection rate of preoperative ocular fundus diseases by fundus pre-set lens was 92.1% while the coincidence rate of predictive postoperative BCVA was 88.7%.·CONCLUSION:The detection rate of preoperative ocular fundus diseases by fundus pre-set lens examination in preoperative examination of cataract is higher than by direct ophthalmoscope.Combined with lens opacities degree and preoperative BCVA analysis,fundus pre-set lens examination can roughly predict post-operative BCVA in patients with cataract in immature stage.·