Cataract is a common and frequent disease in elderly patients, and about 40% of cataract patients are accompanied by systemic metabolic diseases, and diabetic retinopathy and cataract are the two most common causes of vision loss in diabetic patients. Diabetic patients with cataract lens extraction are more difficult to perform, and may have difficulty in dilating the pupil on the affected side, heavy inflammatory reaction, high incidence of posterior cataract, and accelerated retinopathy after surgery. Therefore, it is recommended that patients with diabetic retinopathy should be treated with fundus photocoagulation prior to cataract extraction or immediately after surgery.
1.What preparations should be made before surgery?
The first step is to assess the patient’s general condition and control of diabetes. Cataract extraction surgery has now become routine and generally requires fasting venous blood glucose control of 9.0 mmol/L or less. Next, the visual function of the affected eye should be evaluated and the possible prognosis should be explained to the patient and his relatives. In general, except for fully mature cataracts, most cataract eyes can be examined by indirect fundoscopy after pupil dilatation, and if the fundus cannot be seen, photopositioning examination can be performed according to red and green sensation, and postoperative visual function can be evaluated with the aid of ocular ultrasound. Some ophthalmologists do not examine the fundus of the patient carefully before cataract surgery and do not find out that the patient has diabetic retinopathy, so that the patient’s vision cannot be restored after surgery (after IOL implantation), which also makes it more difficult to perform vitrectomy (some patients have to remove the IOL during vitrectomy).
2.What should I pay attention to during surgery?
Cataract surgery for diabetic patients is generally performed by both extracapsular extraction and ultrasound emulsification, and the difference in vision outcomes between the two procedures is not significant. However, ophthalmologists recommend a larger optical diameter (6.5 or 7.0 mm) IOL for patients with combined retinopathy to facilitate postoperative observation of the peripheral retina and laser photocoagulation; silicone crystals should also be avoided because: (1) Precipitates tend to deposit on the anterior surface of silicone crystals.
(2) If the posterior capsule is incomplete during vitrectomy, droplets hanging on the posterior surface of the silicone crystal can interfere with the exchange of gas and fluid in the fundus.
(3) If the vitrectomy is filled with silicone oil at the end, when the silicone oil is taken, the silicone oil attached to the posterior surface of the crystal will not be easily removed, and the attached silicone oil will affect the vision; those who have proliferative retinopathy and need vitreous surgery should not implant IOLs, but should perform combined surgery with vitrectomy as the main focus.