Ethical Approval
This is a retrospective study. This study was conducted according to the Declaration of Helsinki and approved by the ethical committee of Eye Hospital of Wenzhou Medical University.
Inclusion criteria
The patients undergoing intravitreal anti-VEGF therapy for fundus diseases at the Eye Hospital of Wenzhou Medical University from 2012 to 2021 were collected in our study. The patients underwent bilateral intravitreal anti-VEGF therapy using a single vial in same day were defined as bilateral injection group. The patients underwent unilateral intravitreal anti-VEGF therapy were defined as unilateral injection group.
Exclusion criteria
The patients less than 18 years old (not using a single vial for bilateral injection). Glaucoma.
Methods for preparation injections on-site
Prepared two sterile table with two sets of surgical instruments. The assistant worn surgical mask, surgical cap, operation gown and sterile gloves after surgical hand antisepsis, disinfected the rubber cover 3 times by 5 % povidone iodine solution, dried the cover by sterile cotton swab, and then drew all drugs by the prepackaged filter needle and prepackaged syringe. Removed the prepackaged filter needle, drew about 0.075ml drug from the head of prepackaged syringe by a disposable aseptic insulin syringe (29-gauge needle), put on the syringe needles. Removed air bubbles from syringes and adjusted the dosage to 0.05ml, put the two syringes on two sterile table respectively. One vial was used for only one patient.
Procedure of intravitreal injection
Intravitreal injection was performed in operating room. The operator worn surgical mask, surgical cap and surgical gown. Performed topical anesthesia (Dropping proparacaine hydrochloride eye drops into both eyes 3 times). Disinfected eyelashes and eyelids by 5 % povidone iodine solution 3 times. After surgical hand antisepsis, the operator paved sterile sheet and sterile surgical drape to mask patient’s nose, mouth, the skin around eye and eyelash. Put the eye speculum, washed conjunctival sac by 2% povidone iodine solution for 30 seconds and then washed repeatedly with normal saline. Marked injected point at 3.5 mm to 4 mm posterior to the corneoscleral limbus by marker caliper. Inserted the needle at a 90° angle, push drugs slowly and removed the needle/syringe. Clamped the conjunctiva at injected point by micro forceps and then press the injection point by sterile cotton swab to prevent drug reflux. Dropped tobramycin and dexamethasone eye ointment into conjunctival sac and covered the transparent eyeshades.
If bilateral intravitreal injection, cleaned the operation table, surgical hand washing, re-disinfect and repeated the steps to perform intravitreal injection on the other eye. When performing bilateral initial, injected the right eye first and then the left eye.
The dosage of anti-VEGF drugs was 0.5mg/0.05ml Ranibizumab (Novartis Pharma Schweiz AG) per eye or 0.5mg/0.05ml Conbercept (Chengdu Kanghong Biotechnologies Co. Ltd) per eye.
Patients management
All the patients were observed in hospital at least 2 hours after injection. Slit-lamp examination and intraocular pressure were performed. Topical antibiotics were used after injection to prevent infection for 3 days. Patients were followed-up in 1 week postoperatively. All patients took 3+PRN or 1+ PRN therapy (monthly injection) according to the diseases.
Statistical Analysis
Statistical analysis were performed by SPSS version 19.0 (SPSS 19.0, Inc., Chicago, IL, USA). Data were recorded including gender, age, diagnosis, the kind of anti-VEGF drugs and the occurrence of infectious endophthalmitis. The age was expressed as mean ± standard deviation. The comparison of age between 2 groups was analyzed by independent t-test. The comparison of gender and the incidence of infectious endophthalmitis between 2 groups was analyzed by chi-square test.