Multiple Subretinal Fluid Blebs After Successful Retinal Detachment Surgery: Incidence, Risk Factors, and Presumed Pathophysiology YONG-KYU KIM, JEEYUN AHN, SE JOON WOO, DUCK JIN HWANG, AND KYU HYUNG PARK PURPOSE:
To investigate the incidence and the clinical factors associated with the occurrence of multiple subretinal fluid (SRF) blebs after successful rhegmatogenous retinal detachment (RD) repair. DESIGN: Retrospective, observational case series. METHODS: We retrospectively investigated the medical records of 185 eyes of 184 patients who had undergone successful RD surgery, either vitrectomy or scleral buckling. Each patient had undergone spectral-domain optical coherence tomography (SDOCT) combined with infrared reflectance (IR) imaging every 3 months postoperatively. We carefully examined postoperative SDOCT and fundus IR images, in an effort to identify any SRF blebs present. RESULTS: Multiple (‡3) SRF blebs were observed in 40 of 185 cases (21.6%). SRF blebs were first detected 1.7 ± 1.8 months postoperatively. In 22 cases that could be fully followed up, SRF blebs were completely absorbed 13.1 ± 6.1 months postoperatively. Multiple logistic regression analysis showed that only young age (3 undulations in a single section) in the outer portion of the detached retina. To characterize the serial morphologic changes typical of SRF bleb, we selected 1 SRF bleb from each patient that could be traced with SDOCT throughout the clinical course, then measured its width and height at baseline (when the SRF bleb first appeared) and at its most prominent stage (when the SRF bleb was highest in OCT images and prominent in IR images) using the caliper tool in the OCT software. STATISTICAL ANALYSIS:
We compared preoperative and intraoperative characteristics between those with and without multiple SRF blebs. Some of these factors were significantly associated with the occurrence of SRF bleb in the univariate analysis, which was performed using either the Student t test for continuous variables or the x2 or Fisher exact test for categorical variables. We performed multiple logistic regression analysis with these
SUBRETINAL FLUID BLEB AFTER RETINAL DETACHMENT SURGERY
835
FIGURE 2. Subretinal fluid blebs after successful rhegmatogenous retinal detachment surgery. (Left) One month after the surgery, multiple bleb-like lesions are visible on superior temporal area. (Middle) Three months after the surgery, blebs became more prominent, represented as dark, round lesions on infrared reflectance (IR) scanning laser ophthalmoscopy. (Right) These lesions are revealed to be subretinal fluid (SRF) pockets in spectral-domain optical coherence tomography (SDOCT). The SDOCT images were obtained along the green arrows in IR images. Note that subfoveal fluid bleb (Right, lower) is located apart from multiple SRF blebs in the superior temporal area (Right, upper).
FIGURE 3. Comparison of the incidence of multiple subretinal fluid (SRF) blebs after successful rhegmatogenous retinal detachment surgery in different age groups. *P value < .05, Fisher exact test.
factors to eliminate confounding effects. All statistical analyses were performed using PASW version 18.0 (SPSS, Inc, Chicago, Illinois, USA), and P values < .05 were considered statistically significant.
RESULTS THE 185 EYES (184 PATIENTS) THAT UNDERWENT SUCCESS-
ful primary rhegmatogenous RD repair were ultimately included. Multiple SRF blebs were observed postoperatively in 40 eyes (40 patients) out of 185 eyes (21.6%). In most cases (33 cases, 82.5%), SRF blebs were first 836
detected at 1 month postoperatively; another 5 cases (12.5%) exhibited SRF blebs within 6 months after the surgery. In 2 cases (5%) with diffuse persistent subclinical SRF, SRF blebs first occurred at 8 months postoperatively, as SRF was absorbed. Overall, SRF bleb was first identified on SDOCT 1.7 6 1.8 (mean 6 SD) months postoperatively. In 22 cases, we were able to confirm the complete absorption of SRF blebs with SDOCT during the followup period. The SRF blebs were completely absorbed within 1 year after surgery in 10 cases (45.5%) and within 2 years postoperatively in another 10 cases (45.5%). The longest duration of SRF blebs was 28 months postoperatively (13.1 6 6.1 months postoperatively). For those 18 cases that we could not follow fully until the SRF blebs were completely absorbed, the OCT follow-up period was relatively short (3.6 6 2.4 months). The cumulative survival curve of SRF bleb during the follow-up period is represented in Figure 1. Figure 2 shows an example of a color fundus photograph and fundus IR and SDOCT images of multiple SRF blebs. The SRF blebs are more readily visible on IR images, as round dark lesions. They can be found anywhere in the previously detached retina, either submacularly or peripherally. In SDOCT images, these dark lesions were revealed to be small subretinal fluid pockets. In Figure 2, the subfoveal fluid, separated from multiple SRF blebs in the superior temporal area, is apparent. In this study, we did not count eyes with subfoveal fluid alone as a multiple SRF bleb case. Demographics and clinical characteristics were compared between eyes with and without multiple SRF blebs. Patients with multiple SRF blebs were younger (36.6 6 20.2 years vs 47.2 6 15.9 years, P ¼ .003) than those in the control group. When we stratified patient age by quartile, multiple SRF blebs were most prevalent in the youngest age group (7 days, n (%) Refractive error (SEQ, diopters), mean 6 SD Phakia, n (%) Macula off, n (%) Number of tears, mean 6 SD Tear location, n (%) Superior Inferior Combined Extent of RD (clock hours), mean 6 SD 1-6 o’clock, n (%) 7-12 o’clock, n (%) Preoperative severe retinal undulation, n (%) Operation methods, n (%) Pars plana vitrectomy Scleral buckling Combined Preoperative BCVA (logMAR), mean 6 SD 1 month BCVA (logMAR), mean 6 SD Final BCVA (logMAR), mean 6 SD
Multiple SRF Blebs (þ) (N ¼ 40)
Multiple SRF Blebs (-) (N ¼ 145)
36.6 6 20.2 20 (50) 7 (17.5) 6 (15) 7 (17.5) 24 (60) 15.4 6 9.1 13.9 6 24.6 25 (62.5) 15 (37.5) 2.9 6 5.3 (N ¼ 25) 39 (97.5) 35 (87.5) 2.1 6 1.4
47.2 6 15.9 22 (15.2) 37 (25.5) 53 (36.6) 33 (22.8) 88 (60.7) 14.1 6 9.4 10.2 6 15.8 102 (70.3) 43 (29.7) 3.4 6 4.1 (N ¼ 75) 120 (82.8) 93 (64.1) 2.1 6 1.5
24 (60) 12 (30) 4 (10) 5.5 6 2.1 33 (82.5) 7 (17.5) 7/27 (25.9) 12 (30) 28 (70) 0 1.13 6 0.83 (N ¼ 32) 0.40 6 0.30 (N ¼ 33) 0.21 6 0.34 (N ¼ 23)
Odds Ratio
95% CI
4.3 0.9 0.5 1.0
1.6-11.8 0.3-2.8 0.2-1.7 0.5-2.0
0.6 -
0.3-1.3 -
8.1 3.9
1.1-61.9 1.4-10.6
102 (70.3) 26 (17.9) 17 (11.7) 5.2 6 1.9 123 (84.8) 22 (15.2) 13/100 (13)
1.0 2.0 -
0.3-3.2 0.5-7.1 -
0.8 2.3
0.3-2.1 0.8-6.6
88 (60.7) 54 (37.2) 3 (2.1) 0.94 6 0.88 (N ¼ 122) 0.38 6 0.32 (N ¼ 121) 0.14 6 0.18 (N ¼ 105)
0.3 -
0.1-0.6 -
-
-
P Valuea
.003 .005 .845 .294 .937 .460 .395 .230 .628 .018 .005 .823 .247 >.999 .305 .312 .720 .135 .001 .001 .231 .457 .982
BCVA ¼ best-corrected visual acuity; CI ¼ confidence interval; LogMAR ¼ logarithm of the minimal angle of resolution; RD ¼ retinal detachment; SD ¼ standard deviation; SEQ ¼ spherical equivalent; SRF ¼ subretinal fluid. a P values by Student t test or Mann-Whitney test for continuous variables and by x2 test or Fisher exact test for categorical variables. P values that are statistically significant (
To investigate the incidence and the clinical factors associated with the occurrence of multiple subretinal fluid (SRF) blebs after successful rhegmatogenous retinal detachment (RD) repair. DESIGN: Retrospective, observational case series. METHODS: We retrospectively investigated the medical records of 185 eyes of 184 patients who had undergone successful RD surgery, either vitrectomy or scleral buckling. Each patient had undergone spectral-domain optical coherence tomography (SDOCT) combined with infrared reflectance (IR) imaging every 3 months postoperatively. We carefully examined postoperative SDOCT and fundus IR images, in an effort to identify any SRF blebs present. RESULTS: Multiple (‡3) SRF blebs were observed in 40 of 185 cases (21.6%). SRF blebs were first detected 1.7 ± 1.8 months postoperatively. In 22 cases that could be fully followed up, SRF blebs were completely absorbed 13.1 ± 6.1 months postoperatively. Multiple logistic regression analysis showed that only young age (3 undulations in a single section) in the outer portion of the detached retina. To characterize the serial morphologic changes typical of SRF bleb, we selected 1 SRF bleb from each patient that could be traced with SDOCT throughout the clinical course, then measured its width and height at baseline (when the SRF bleb first appeared) and at its most prominent stage (when the SRF bleb was highest in OCT images and prominent in IR images) using the caliper tool in the OCT software. STATISTICAL ANALYSIS:
We compared preoperative and intraoperative characteristics between those with and without multiple SRF blebs. Some of these factors were significantly associated with the occurrence of SRF bleb in the univariate analysis, which was performed using either the Student t test for continuous variables or the x2 or Fisher exact test for categorical variables. We performed multiple logistic regression analysis with these
SUBRETINAL FLUID BLEB AFTER RETINAL DETACHMENT SURGERY
835
FIGURE 2. Subretinal fluid blebs after successful rhegmatogenous retinal detachment surgery. (Left) One month after the surgery, multiple bleb-like lesions are visible on superior temporal area. (Middle) Three months after the surgery, blebs became more prominent, represented as dark, round lesions on infrared reflectance (IR) scanning laser ophthalmoscopy. (Right) These lesions are revealed to be subretinal fluid (SRF) pockets in spectral-domain optical coherence tomography (SDOCT). The SDOCT images were obtained along the green arrows in IR images. Note that subfoveal fluid bleb (Right, lower) is located apart from multiple SRF blebs in the superior temporal area (Right, upper).
FIGURE 3. Comparison of the incidence of multiple subretinal fluid (SRF) blebs after successful rhegmatogenous retinal detachment surgery in different age groups. *P value < .05, Fisher exact test.
factors to eliminate confounding effects. All statistical analyses were performed using PASW version 18.0 (SPSS, Inc, Chicago, Illinois, USA), and P values < .05 were considered statistically significant.
RESULTS THE 185 EYES (184 PATIENTS) THAT UNDERWENT SUCCESS-
ful primary rhegmatogenous RD repair were ultimately included. Multiple SRF blebs were observed postoperatively in 40 eyes (40 patients) out of 185 eyes (21.6%). In most cases (33 cases, 82.5%), SRF blebs were first 836
detected at 1 month postoperatively; another 5 cases (12.5%) exhibited SRF blebs within 6 months after the surgery. In 2 cases (5%) with diffuse persistent subclinical SRF, SRF blebs first occurred at 8 months postoperatively, as SRF was absorbed. Overall, SRF bleb was first identified on SDOCT 1.7 6 1.8 (mean 6 SD) months postoperatively. In 22 cases, we were able to confirm the complete absorption of SRF blebs with SDOCT during the followup period. The SRF blebs were completely absorbed within 1 year after surgery in 10 cases (45.5%) and within 2 years postoperatively in another 10 cases (45.5%). The longest duration of SRF blebs was 28 months postoperatively (13.1 6 6.1 months postoperatively). For those 18 cases that we could not follow fully until the SRF blebs were completely absorbed, the OCT follow-up period was relatively short (3.6 6 2.4 months). The cumulative survival curve of SRF bleb during the follow-up period is represented in Figure 1. Figure 2 shows an example of a color fundus photograph and fundus IR and SDOCT images of multiple SRF blebs. The SRF blebs are more readily visible on IR images, as round dark lesions. They can be found anywhere in the previously detached retina, either submacularly or peripherally. In SDOCT images, these dark lesions were revealed to be small subretinal fluid pockets. In Figure 2, the subfoveal fluid, separated from multiple SRF blebs in the superior temporal area, is apparent. In this study, we did not count eyes with subfoveal fluid alone as a multiple SRF bleb case. Demographics and clinical characteristics were compared between eyes with and without multiple SRF blebs. Patients with multiple SRF blebs were younger (36.6 6 20.2 years vs 47.2 6 15.9 years, P ¼ .003) than those in the control group. When we stratified patient age by quartile, multiple SRF blebs were most prevalent in the youngest age group (7 days, n (%) Refractive error (SEQ, diopters), mean 6 SD Phakia, n (%) Macula off, n (%) Number of tears, mean 6 SD Tear location, n (%) Superior Inferior Combined Extent of RD (clock hours), mean 6 SD 1-6 o’clock, n (%) 7-12 o’clock, n (%) Preoperative severe retinal undulation, n (%) Operation methods, n (%) Pars plana vitrectomy Scleral buckling Combined Preoperative BCVA (logMAR), mean 6 SD 1 month BCVA (logMAR), mean 6 SD Final BCVA (logMAR), mean 6 SD
Multiple SRF Blebs (þ) (N ¼ 40)
Multiple SRF Blebs (-) (N ¼ 145)
36.6 6 20.2 20 (50) 7 (17.5) 6 (15) 7 (17.5) 24 (60) 15.4 6 9.1 13.9 6 24.6 25 (62.5) 15 (37.5) 2.9 6 5.3 (N ¼ 25) 39 (97.5) 35 (87.5) 2.1 6 1.4
47.2 6 15.9 22 (15.2) 37 (25.5) 53 (36.6) 33 (22.8) 88 (60.7) 14.1 6 9.4 10.2 6 15.8 102 (70.3) 43 (29.7) 3.4 6 4.1 (N ¼ 75) 120 (82.8) 93 (64.1) 2.1 6 1.5
24 (60) 12 (30) 4 (10) 5.5 6 2.1 33 (82.5) 7 (17.5) 7/27 (25.9) 12 (30) 28 (70) 0 1.13 6 0.83 (N ¼ 32) 0.40 6 0.30 (N ¼ 33) 0.21 6 0.34 (N ¼ 23)
Odds Ratio
95% CI
4.3 0.9 0.5 1.0
1.6-11.8 0.3-2.8 0.2-1.7 0.5-2.0
0.6 -
0.3-1.3 -
8.1 3.9
1.1-61.9 1.4-10.6
102 (70.3) 26 (17.9) 17 (11.7) 5.2 6 1.9 123 (84.8) 22 (15.2) 13/100 (13)
1.0 2.0 -
0.3-3.2 0.5-7.1 -
0.8 2.3
0.3-2.1 0.8-6.6
88 (60.7) 54 (37.2) 3 (2.1) 0.94 6 0.88 (N ¼ 122) 0.38 6 0.32 (N ¼ 121) 0.14 6 0.18 (N ¼ 105)
0.3 -
0.1-0.6 -
-
-
P Valuea
.003 .005 .845 .294 .937 .460 .395 .230 .628 .018 .005 .823 .247 >.999 .305 .312 .720 .135 .001 .001 .231 .457 .982
BCVA ¼ best-corrected visual acuity; CI ¼ confidence interval; LogMAR ¼ logarithm of the minimal angle of resolution; RD ¼ retinal detachment; SD ¼ standard deviation; SEQ ¼ spherical equivalent; SRF ¼ subretinal fluid. a P values by Student t test or Mann-Whitney test for continuous variables and by x2 test or Fisher exact test for categorical variables. P values that are statistically significant (
