Anales de la RANM

249 A N A L E S R A N M R E V I S T A F U N D A D A E N 1 8 7 9 Laura Morales An RANM. 2021;138(03): 246 - 255 ASSOCIATION BETWEEN VASCULAR AND STRUCTURAL PARAMETERS circle centred on the fovea, an inner circle (iC) from 1 to 3 mm, an outer circle (oC) from 3 to 6 mm and a whole circle (w) (Figure 1.b). All mPD and macular VD measurements (global and circles) were collected. And foveal avascular zone (FAZ) was analysed: FAZ area (the macular foveal area without blood flow signal, mm 2 ), the FAZ perimeter (mm), and the acicularity index (the measured perimeter of FAZ-to- the perimeter of projected circle ratio with the same area as the FAZ, AI; from 0 to 1). OCT measurements The images of Macular and peripapillary 6x6 mm scans were acquired with the same instru- ment SD-OCT (Cirrus, HD-OCT 5000; Carl Zeiss Meditec, Inc.) to get optic nerve head measure- ments: circumpapillary Retinal nerve feber layer (cpRNFL) thickness (average and quadrants superior, nasal, inferior and temporal), disc area (mm 2 ), rim area (mm 2 ), average C/D ratio and vertical C/D ratio (figure 1.c); and macular measurements: average ganglion cell layer and inner plexiform layer (GCL+IPL) thickness, minimum GCL+IPL thickness and superior, superior nasal, superior temporal, inferior, inferior nasal and inferior temporal GCL+IPL thickness (figure 1.d). Statistical analysis Statistical analyses were performed using SPSS software (version 20.0; SPSS, Inc., Chicago, IL, USA). Descriptive statistics were used to calculate mean and median of the different demographic and clinical parameters. Pearson correlation test was performed to determine the correlation between structural and functional parameters and significance was taken as p<0.05. The study population consisted of 40 PCG patients (median age 11 (9-14.75) years). A total of 51 children with PCG were examined however only 40 were finally included in the study group due to poor quality of exams or impossibility to complete OCTA and/or OCT scans. Demographic and clinical characteristics of the study population are described in table 1. The clinical characteristics of the PCG group were: mean IOP 16.56 (3.87) mmHg (range 7-26 mmHg) and mean number of hypotensive ocular medica- tions used 0.78 (0.67). All eyes required glaucoma surgeries and mean glaucoma surgeries per eye were 1.53 (1.21): in 17 eyes, at least one goniotomy was performed (median number of gonioto- mies per eye was 1.8 (P25-P75= 1.3-2.6). 12 eyes required at least one trabeculectomy (median number of trabeculectomies per eye was 1.2 (P25- P75=1-2) and 3 eyes required the implantation of an Ahmed valve. Table 2 shows all peripapillary OCT and OCT-A measurements. Mean pPD was 42.57 (4.56) % and flux index was 0.39 (0.05). pPD and FI measurements were lower in vertical quadrants than horizontal quadrants (superior pPD=39.06(8.98) % ,inferior pPD=40.39 (5.66)%, superior FI=0.38 (0.05) and inferior FI=0.38 (0.06). the highest pPD and FI values were obtained in the temporal quadrant (pPD=46.48 (3.92) % and FI=0.40(0.06). Average cpRNFL thickness was 78.65 (22.50) microns. cpRNFL thickness in inferior quadrant was lower (92.45 (33.94) microns) than cpRNFL thickness in superior quadrant (93.17 (32.53) microns). All macular OCT and OCT-A measurements are shown in table 3. W-VD was 16.85 (1.92) mm -1 and w- mPD was 41.43 (4.91) %. As expected, lower values for both parameters were found in the central-circle due to FAZ area is included in this measurement (FAZ area= 0.21 (0.09) mm 2 ). Higher values were found for outer circle for both parameters (oC-mPD=42.42 (5.43) % and oC-VD=17.08 (2.10) mm -1 ). Average GCL+IPL thickness was (71.71 (14.81) microns and minimum GCL+IPL thickness was 64.18 (18.63) microns. Table 4 represents the correlation between OCT and OCT-A measurements. FI showed a correlation with structural measurements: average cpRNFL thickness (r=0.707;p<0.001), average GCL+IPL thickness (r=0.568;p<0.001) and minimum GCL+IPL thickness (r=0.521;p=0.001); and with morphologic measure- ments: rim area (r=0.704;p<0.001), average C/D ratio (r=-0.645;p<0.001), vertical C/Dratio (-0.703;p<0.001), cup volume (r=-0.455;p=0.004). pPD showed a correla- tion with structural measurements: average cpRNFL thickness (r=0.722;p<0.001), average GCL+IPL thickness (r=0.510;p=0.001) and minimum GCL+IPL thickness (r=0.417;p=0.001); and with morphologic measurements: rim area (r=0.652;p<0.001), average C/D ratio (r=-0.554;p<0.001), vertical C/D ratio (-0.632;p<0.001), cup volume (r=-0.368;p=0.023). Statistically significant correlation was found between peripapillary structural and vascular parameters in quadrants: Superior RNFL thickness showed a positive correl tion with superior FI (r=0.685;p<0.001) and superior pPD (r=0.582;p<0.001); Inferior RNFL thickness showed a positive correlation with inferior FI (r=0.659;p<0.001) and inferior pPD(r=0.740;p<0.001); temporal RNFL thickness showed a positive correla- tion with temporal FI (r=0.512;p=0.010) and temporal pPD (r=0.663;p<0.001); And nasal RNFL thickness showed a positive correlation with nasal FI (r=0.537;p=0.001) and nasal pPD (r=0.461;p=0.005). Indeed, vascular macular measurements showed a strong correlation with macular structural parameters: GCL+IPL thickness with mVD (r=0.478; p=0.004) and mPD (r=0.477; p=0.004). No correlation was detected between FAZ area and structural macular measurements. RESULTS