Three years after retinal surgery, you should consider vitreous clouding, cloudy posterior lens capsule, refractive error, retinopathy, corneal edema and other factors. 1. Vitreous clouding: retinal surgery requires removal of the vitreous body and injection of vitreous cavity fillers such as silicone oil, inert gas, etc. Common adverse reactions to fillers include proliferation of the vitreous cavity, which can form a pre-retinal membrane and vitreous cavity clouding, resulting in blurred vision and a foggy feeling. 2. Turbidity of the posterior lens capsule: If an IOL is implanted during retinal surgery, the condition of the posterior lens capsule needs to be considered. Due to the residual and proliferation of lens cortical cells, the posterior lens capsule can become cloudy with ground-glass clouding, resulting in a foggy vision, which is feasible to be treated with laser. 3. Refractive error: after retinal surgery, the refractive media, such as vitreous humor and lens, are affected, resulting in refractive changes, causing blurred vision, and optometry is needed to correct the refractive error. 4. Retinopathy: recurrence of retinal detachment will cause blurred vision, and should immediately seek medical attention for fundus examination, ultrasound, etc. to make a clear diagnosis. 5. Corneal edema: The residual filler in the retinal surgery will block the angle of the atrium, resulting in increased intraocular pressure, corneal edema, the patient will have foggy vision, if accompanied by eye pain and swelling, need to consult a doctor immediately, check the intraocular pressure and fundus. Retinal surgery is mostly used to treat retinal detachment, vitreous hemorrhage, retinal tears, choroidal detachment, endophthalmitis, etc. If you have blurred vision like fog after three years, you should seek immediate medical attention for prompt treatment.