2.1 Research Methods and Patients
This retrospective study was approved by the Ethics Committee of the Affiliated Eye Hospital of Nanchang University. All patients signed an informed consent form, and all studies and measurements adhered to the principles of the Helsinki Declaration. This study included 32 patients (32 eyes) diagnosed with a large SMH and PCV between January 2021 and September 2021. A large SMH is defined to have a diameter of ≥ 4 disc diameters (DD) [12]. The inclusion criteria were as follows: (a) Patients diagnosed with macular hemorrhage through fundus examination, with a hemorrhage size of > 4DD; (b) the duration of sudden visual impairment in the affected eye did not exceed 2 weeks; and (c) patients with PCV diagnosed with indocyanine green angiography (ICGA) or those who met the non-ICGA diagnostic criteria for optical coherence tomography. The exclusion criteria were as follows: (a) patients with previous macular hole, macular splitting, macular atrophy, and typical age-related macular degeneration, among others, which could cause changes in macular morphology and structure; (b) other eye diseases, including diabetes retinopathy, ischemic retinopathy, high myopia, glaucoma, and uveitis; (c) previous vitreoretinal surgery; (d) SMH caused by other macular diseases; (e) severe heart, lung, liver and kidney dysfunction, and anticoagulant users. All patients underwent vitrectomy combined with subretinal injection of tPA and intravitreal injection of Conbercept for treatment.
2.2 Whole body and eye examinations
Before surgery, complete ophthalmic examinations were conducted on all patients included in the study, including best corrected visual acuity (BCVA), slit lamp microscopy with a front mirror and indirect dilated fundus examination, non-contact tonometry, spectral domain optical coherence tomography (SD-OCT) (Heidelberg, Germany), and fundus photography (Oberg, UK), fundus fluorescein angiography, and ICGA (Heidelberg Engineering Company). The SD-OCT built-in caliper was used to measure the thickness of the subfornix hemorrhage; the thickest part was scanned to determine the size and location of the subretinal hematoma. The manual caliper function of the ImageNet software was used to measure and calculate the area of the SMH in square millimeters on fundus photographs. BCVA was assessed in logarithmic minimum angle of resolution (logMAR) for inspection, evaluation, and representation.
2.3 Surgical process
All patients received surgical treatment after completing preoperative examinations. We used a 23G vitrectomy system (ALCON Constellation, USA) for vitrectomy. After vitrectomy, we connected a 41G ultra-precision microneedle (MedOne, USA) to a 1ml syringe, and connected the vitrectomy system through a hose. In silicone oil injection mode (with a pressure of 10psi), the configured tPA (250ug/ml) was injected into the subepithelial space. Based on the preoperative SD-OCT results, the injection site had to be selected in an area far away from the RPE with a high detachment rate to avoid penetrating the RPE and causing damage. At the same time, the injection had to avoid the fovea of the macula. We used the foot pedal of the vitrectomy machine to control the injection speed and amount. The injection dose was selected based on the bleeding volume (0.05–0.1 ml) of the patient, and 1–2 parts were selected for injection according to the bleeding area and protrusion height. During the injection process, a vesicular retinal detachment area could be seen under the retina. After complete air-liquid exchange following the injection, 2mg/0.05mL of Conbercept intraocular injection solution was injected into the vitreous cavity. Silicone oil or gas was injected based on the amount of bleeding under the retina. All scleral incisions were sutured with Vicryl 7 − 0 at the end of the surgery. All patients needed to maintain prone for 3 days after surgery, and multiple slow alternating head postures were required within the first day after surgery to facilitate the full mixing of tPA and hemocoel.
2.4 Postoperative follow-up
Patients were followed up and observed at 1 month and 3, 6, and 12 months after surgery. They received a second injection of 2mg/0.05ml of Conbercept intravenously one month and 2 months after surgery, and the decision to continue injecting Conbercept was made based on the healing of the lesion after the third month. The criteria for re-injection were new bleeding, persistent or new subretinal fluid accumulation on SD-OCT, or ICGA indicating incomplete resolution of PCV lesions. BCVA, slit lamp examination, intraocular pressure examination, Auger fundus photography, and SD-OCT, among others, were performed during each postoperative follow-up visit.
2.5 Evaluation indicators
The preoperative and postoperative BCVA and macular fovea thicknesses (CMT) were compared. The intraoperative and postoperative complications, clearance rate of macular hemorrhage, and recurrence rate of macular subretinal hemorrhage were also observed. The complete clearance of macular hemorrhage was defined as the clearance of subretinal hemorrhage within a radius of 2DD centered around the fovea of the macula.
2.6 Statistical analysis
The patient baseline characteristics were analyzed using IBM SPSS version 2.0 software (IBM SPSS Company, Chicago, Illinois, USA). The categorical demographic and baseline data are expressed as frequency and percentage, and the continuous data are expressed as mean and standard deviation (\(\stackrel{-}{x}\)±S). For statistical purposes, BCVA was recorded as logMAR. The preoperative and postoperative BCVA were compared using repeated measures analysis of variance. The blood clearance rate, recurrence rate, and number of complications were recorded as percentages. Two-tailed P-values of less than 0.05 denoted statistical significance.