Clinical Characteristics And Prognostic Factors Of Choroidal Neovascularization Secondary To Older Pathological Myopia

Objective:To observe the influence of age factors on myopic choroid neovascularization（CNV）by function and morphology and to evaluate response and recurrence of intravitreal conbercept on PMCNV patients as well as the predictive factors.Methods:In this retrospective study,64 patients（64 eyes）with pathological myopia（PM）CNV were included from April 2015 to April 2018.The cases were split into the younger group（<50 years）and the older group（≥50 years）,and the differences in baseline best corrected visual acuity（BCVA）andmorphological feature on imaging were analyzed.Of all,21 eyes of 21 PMCNV patients aged over 50 years who received conbercept injection with 1+PRN（pro re nata）regimen were further analyzed.We collected functional and morphological data at 1^st,3^rd,6^th and 12^th months after treatment to assess the efficacy of the patients;baseline prognostic factors that may affect the visual acuity within 1 year after treatment were screened,such as age,axial length,BCVA,CMT,type of effusion,CNV position,CNV size,etc al.In addition,the recurrence of patients after treatment was observed during the follow-up and we used the Cox proportional risk regression model to analyze the factors that might affect the recurrence.Results:The average age of 25 cases in the younger group was 37.56±7.78 years and the average age of 39 cases in the older group was 59.67±8.40 years.The mean baseline BCVA（log MAR）of the younger group and the older group were 0.58±0.28 and 0.77±0.31respectively,with statistically significant differences（t=2.439,P=0.018）.In terms of morphological features in OCT,the average subfoveal choroidal thickness（SFCT）of the younger group and the older group were 108.17±78.32μm and 54.68±39.03μm respectively,with statistically significant differences（t=-3.11,P<0.01）.The central macular thickness（CMT）,the presence of intraretinal fluid（IRF）and subretinal fluid（SRF）,the integrity of external limiting membrane（ELM）and ellipsoid zone（EZ）,CNV area,and leakage area were found no significant difference between the older group and the younger group（P>0.05）.In vitreoretinal interface abnormalities,there were 13 cases of complications in the older group（6 cases of retinoschisis,2 cases of vitreoretinal adhesion,and 5 cases of vitreoretinal traction）and 2 cases in the younger group（2 cases of vitreous cortical adhesion）,with statistically significant differences（P=0.028）.In the conbercept treatment assessment part,the average number of treatment times was 1.71±0.90 and all patients were followed for than 12 months.Compared with the baseline mean BCVA（0.83±0.30）,the mean BCVA at 1^st,3^rd,6^th,and 12^th months after treatment were 0.62±0.33,0.56±0.30,0.47±0.26,and 0.49±0.24,with statistically significant differences（t=2.835,3.117,3.278,3.445,P<0.05）.There were 7（33.3%）recurrent cases during follow-up among the 21 patients and the mean recurrence time was9.40±3.83 months after treatment.The average number of treatment time was 2.71±0.76 in recurrence patients,which was significantly higher than the average number of 1.21±0.43times in the group without recurrence（t=5.872,P<0.001）.In terms of prognostic factors,the baseline BCVA was positively correlated with their visual acuity at 1-year follow-up after conbercept treatment（t=4.341,P=0.001）and patients with ELM damage had worse visual acuity at 1-year follow-up（t=3.711,P=0.002）.The CNV area was negatively correlated with the visual acuity at each follow-up time（F=5.738,P=0.038）,and the CNV location had a statistically significant difference in the visual acuity of each follow-up time（F=7.399,P=0.025）.The risk of recurrence in patients with CMT≥262.86μm was 14 times that of patients with CMT<262.86μm within one year.The risk of recurrence in patients increased by 1.84times for every incremental 100μm on CMT（P=0.028,HR=1.842）.Other baseline factors were not significantly correlated with recurrence.Conclusion:PMCNV patients over 50 years of age had worse BCVA,thinner choroid and a higher risk of vitreoretinal interface abnormalities than young PM patients.Standard conbercept treatment strategy was still safe and effective in PMCNV patients over 50 years of age.Patients with poor baseline BCVA and severe baseline ELM damage had worse vision acuity.Patients with good baseline BCVA,small CNV,and juxtafoveal CNV had better vision.Elderly patients with thick CMT have a high risk of recurrence,therefore more attention should be paid and patients should be closely followed.