1. Envelop capsulotomy was done to the 3 eyes ( 5.1 % ) which failed in the former operation.

2. Results: Squareshaped anterior capsulotomy was well done in 56 eyes ( 94.9 % ) during the operation.

3. High elasticity facilitates capsulotomy and affords ocular protection against high - frequency mechanical insults.

4. To explore the choice of operation methods of ND :YAG laser posterior capsulotomy for the treatment of after lens implant surgery and the prevention of complications.

5. Objective : To investigate the effect of square shaped anterior capsulotomy in extracapsular extraction for cortical cataract.

6. Objective : To observe retinometer for potential visual acuity before YAG laser posterior capsulotomy.

7. Objective To study the clinical value of treading after cataract posterior capsulotomy via pars plana.