Natural history of persistent subretinal fluid following the successful repair of rhegmatogenous retinal detachment

Abstract

Aim: To provide a detailed description of the natural history of persistent subretinal fluid (SRF) after successful repair of rhegmatogenous retinal detachment (RRD) and its association with visual outcome.

Methods: This was a prospective long-term follow-up for eyes undergoing scleral buckling (SB) surgery for macula-off RRD. Examinations were carried out preoperatively and postoperatively at 1, 3, 6, 9 and 12mo, until persistent SRF had completely resolved. One month postoperatively, optical coherence tomography (OCT) was used to classify SRF into three patterns: bleb-like loculated (BL), shallow-diffused (SD), and multiple blebs (MB). Serial OCT imaging was used to evaluate morphological changes in SRF until its complete disappearance. Patients were divided into two groups depending on the presence or absence of persistent SRF.

Results: A total of 59 patients (59 eyes) were included. There were no statistical differences between two groups at baseline, except for the proportion of patients with high myopia and a younger age. One month after surgery, OCT detected persistent SRF in 49 eyes (83.1%). The 3 morphological patterns of SRF were observed in 27 eyes (55.1%) with BL, 13 eyes (26.5%) with SD, and 9 eyes (18.4%) with MB. The mean time for complete absorption differed significantly across the three SRF patterns (F=8.097, P=0.001), which was 8.8±6.1, 20.1±12.1, and 16.7±10.2mo in BL, SD, and MB, respectively. In 9 of the 13 eyes with SD, the pattern transformed into MB type. In cases involving MB, the size and number of blebs decreased gradually until they had been completely absorbed. Eyes with persistent SRF were more likely to demonstrate disruption of the ellipsoid zone (49.0% vs 10%, P=0.034). The final best-corrected visual acuity of two groups was 0.37±0.11 (with SRF) vs 0.34±0.12 (without SRF) logMAR (P=0.499), respectively.

Conclusion: High preoperative myopia and younger age are associated with persistent SRF. BL is the most commonly observed pattern with the shortest duration and gradually disappeared. Most cases involving SD SRF transform into MB type during resolution. The size and number of the MBs decrease gradually until they were completely absorbed. The absence of persistent SRF may contribute to slow visual recovery in the short-term but does not influence the final visual outcome.

Keywords: optical coherence tomography; rhegmatogenous retinal detachment; subretinal fluid; visual acuity.

Figure 1. Three patterns of SRF on OCT: BL (A), SD (B), and MB (C).

Figure 2. Flow chart showing patient inclusion/exclusion.

Figure 3. Changes in BCVA during follow-up after SB surgery for patients with macula-off RRD

The mean preoperative BCVA values at baseline were 1.25±0.30 logMAR and 1.24±0.26 logMAR in eyes with and without SRF, respectively. Subgroup analysis between groups of patients with and without SRF showed that the mean BCVA in the SRF group was significantly worse than patients without SRF at the 1- and 3-month follow-up timepoints (P=0.022 and 0.029, respectively). However, there were no significant differences throughout the rest of the follow-up period (P=0.081 at 6mo, P=0.272 at 9mo, P=0.829 at 12mo, and P=0.499 at the final visit). ^aP<0.05.

Figure 4. Cumulative persistence curves of the three SRF patterns

^bCensored cases.

Figure 5. The natural evolution of SD SRF after SB surgery

Images represent serial OCT images showing the natural course of a 41-year-old patient with SD SRF after SB surgery for macula-off RRD. A: Diffused SRF was observed 1mo after surgery. BCVA was 0.7 logMAR. B: Three months after surgery, the SRF pattern had transformed from the diffuse type to the MB type, with discontinuous retinal reattachment. BCVA was 0.7 logMAR. C: Six months after surgery, the width of the SRF had decreased. BCVA was 0.6 logMAR. D: Nine months after surgery, the width and number of blebs had decreased, BCVA was 0.4 logMAR. E: Twelve months after surgery, the blebs showed gradual regression, leaving a single bleb. BCVA was 0.3 logMAR. F: Fifteen months after surgery, the width of the single bleb SRF had decreased. BCVA was 0.3 logMAR. G: Complete resolution of bleb SRF was confirmed 18mo after surgery. BCVA was 0.2 logMAR.