Objective:To observe the efficacy and safety of individual dose of intravitreal conbercept (IVC) in the treatment of retinopathy of prematurity (ROP) before type 1 threshold.Methods:A retrospective case study. From January to July, 2019, 23 cases (46 eyes) of children with type 1 pre-threshold ROP were included in the study. Among them, 14 cases (28 eyes) were male and 9 cases (18 eyes) were female. The mean gestational age at birth was 28.06±1.73 weeks. The average birth weight was 1.14±0.19 kg. The mean corrected gestational age was 34.38±1.41 weeks at the time of first intravitreal injection of IVC. The axial length (AL) of children was measured by A-mode ultrasound before IVC for the first time. According to the calculation of AL, the corresponding injection dose range was 14.23-16.19, 16.20-17.57, 17.58-18.63 mm and the injection dose of IVC was 0.015, 0.020, 0.025 ml (including IVC was 0.15, 0.20, 0.25 mg, respectively). The first IVC dose was 0.015 ml. On the first day before IVC and on the first and seventh days after IVC, 2 ml of arterial blood was taken from children, serum vascular endothelial growth factor (VEGF) concentration was detected. The follow-up time after treatment was ≥1 year. After one year of follow-up, the effective rate and recurrence rate of IVC for the first time were tested by χ2 tests. The short-term changes of injection times, injection intervals, retinal vascularization time and serum VEGF concentration in children were tested by t test. Results:Retinal neovascularization subsided and vascular buckling decreased in all eyes. Iris neovascularization subsided, 1-3 weeks after IVC for the first time. Within one year after the first IVC, 16 eyes underwent IVC twice with or without new blood vessels at the junction of the vascular area. The average corrected gestational age was 40.56±3.81 weeks. The injection dose of IVC was 0.015 ml and 0.020 ml for 2 eyes and 14 eyes, respectively.The mean interval from IVC for the first time was 40.89±8.99 days. Of the 16 eyes who underwent IVC twice, 8 eyes showed neovascularization again in the retinal area with or without blood vessels. The average corrected gestational age was 43.00±1.41 weeks. The injection dose of IVC was 0.020 ml and 0.025 ml for 3 eyes and 5 eyes, respectively. The mean interval of the second IVC was 28.60±6.07 days. The mean interval from the first IVC was 69.20±12.40 days. At the end of follow-up, all eyes were treated effectively (100%, 46/46). The mean time of retinal vascularization was 46.31±3.42 weeks. The average number of injections was 1.52±0.76. On the first day before IVC and on the first and seventh days after IVC, the average serum VEGF concentrations were 111.21±148.71, 25.60±27.71 and 42.99±38.01 pg/ml, respectively. Serum VEGF concentration was significantly lower than that before IVC on the 1st and 7th day after IVC ( Z=-4.054, -2.779; P<0.05). Serum VEGF concentration was higher 7 days after IVC than 1 day after IVC, and the difference was statistically significant ( Z=-2.505, P<0.05). All eyes were not treated by laser photocoagulation or vitrectomy. No eye complications such as lens opacification, endophthalmitis and retinal detachment related to drugs or treatment methods were found in all patients. Conclusion:Intravitreal injection of individualized dose of IVC is effective in the treatment of type 1 pre-threshold ROP. Seven days after treatment, serum VEGF concentration of patients’serum decreases.

Objective:To evaluate macular microvessel changes in familial exudative vitreoretinopathy (FEVR) by optical coherence tomography angiography.Methods:Cross-sectional clinical case-control study. From November 2019 to November 2020, 21 FEVR patients (41 eyes) from Weifang Eye Hospital were selected; 17 healthy volunteers (28 eyes) with the same age and gender as FEVR group were selected as normal control group. According to the best corrected visual acuity (BCVA) 1.0 and <1.0, FEVR group was divided into normal visual acuity group (27 eyes) and visual acuity decreased group (14 eyes). All enrollees received BCVA and OCTA. BCVA was performed with an international standard visual acuity chart, which was converted to logarithm of the minimum angle of resolution (logMAR) vision. The OCTA instrument was used to scan the macular area of all the examined eyes in the range of 3 mm×3 mm, 6 mm×6 mm, and the blood vessel density (VD) and blood perfusion density (PD) within the range of 3 mm×3 mm, 6 mm×6 mm were measured and the area, circumference, and morphological index of the foveal avascular zone (FAZ) within the range of 6 mm×6 mm. Quantitative data were compared between groups by independent sample t test. Statistical data were compared by χ 2 test. The area under curve (AUC) of each index was determined according to receiver operating characteristic curve (ROC curve), and the predictive value of each index was evaluated. Results:In the macular area of 6 mm×6 mm, VD, PD, FAZ area and FAZ perimeter of FEVR group were all lower than those of normal control group, and the differences were statistically significant ( t=-3.350, -2.387, -3.519, -3.029; P<0.05). In macular area of 3 mm×3 mm and 6 mm×6 mm, compared with normal vision group and vision loss group, both VD and PD decreased. The differences were statistically significant ( t=2.088, 2.114, 2.160, 2.545; P<0.05). In the macular area of 6 mm×6 mm , the FAZ morphological index of the two groups was significantly different ( t=2.409, P<0.05). ROC curve analysis showed that all the indicators had low diagnostic value for FEVR (AUC<0.5). Conclusion:There are microvascular abnormalities in macular area in FEVR patients, and the decrease of blood vessels and the change of FAZ shape may be related to the loss of visual acuity.