The aim of this study is to evaluate corneal endothelial cell changes after pars plana vitrectomy in Rhegmatogenous Retinal detachment , compare the results using different silicon oil viscositites , and assess whether these changes are reversible after silicone removal or not .

The aim of this study is to evaluate corneal endothelial cell changes after pars plana vitrectomy in Rhegmatogenous Retinal detachment , compare the results using different silicon oil viscositites , and assess whether these changes are reversible after silicone removal or not .

Inclusion Criteria:

- All patients with Rhegmatodenous retinal detachment which need PPV will be included in this study.

Exclusion Criteria:

• Patients with corneal dystrophies or degeneration.
• Patients with a history of refractive surgery, either corneal or phakic lOL implantation.
• Patients with a history of keratoplasty.
• Patients with history of retinal detachment surgery in the same eye.
• Recurrent cases during the follow-up period will be removed from the study. 6. patients with gas tamponade 7. patients with silicon oil 1000 cs 8. patients with Retinal pathologies such as macular hole , diabetic changes 9. patients undergo phacovitrectomy

All patients with Rhegmatodenous retinal detachment which need PPV will be included in this study.