Real-Time In Vivo Assessment of Retinal Reattachment in Humans Using Swept-Source Optical Coherence Tomography

Morphologic Features of Regulated vs. Dysregulated Rhegmatogenous Retinal Detachment Using Swept-Source Optical Coherence Tomography

OBJECTIVE

To describe varying morphological features of patients with RRD based on the extent of regulation of the subretinal space by the retinal pigment epithelium (RPE) pump using swept-source optical coherence tomography (SS-OCT).

DESIGN

Prospective clinical cohort study. Methods SETTING: St. Michael's Hospital, Toronto, Canada, from August 2020-August 2023.

PARTICIPANTS

120 consecutive eyes with primary RRD.

COHORTS

Subclinical, non-progressive, localized RRD defined as regulated vs. acute, progressive, and extensive defined as dysregulated assessed with swept-source SS-OCT.

MAIN OUTCOME

Morphological features of regulated vs dysregulated RRDs with SS-OCT.

RESULTS

19.2 % (23/120) of RRDs were classified as regulated and 80.8% (97/120) were dysregulated. The mean age of patients with regulated RRDs was 37.1 years (±13.7 SD) versus 62.6 years (±11.6SD) for patients with dysregulated RRDs (P<0.001). The presence of outer retinal corrugations (ORCs) on OCT was observed in 4.3%(1/23) of regulated vs 81.4% (79/97) of dysregulated RRDs (P<0.001). CME was found in 41.6%(5/12) of regulated RRDs compared to 87.3%(83/95) of dysregulated RRDs(P<0.001). ORC presence was an independent predictor of having a dysregulated RRD (P= 0.02,β = 6.6,95 %CI [1.3 -33.2]) when controlling for age, sex, baseline VA, lens status, and RD extent. Among patients with regulated RRDs, 25.0% (3/12) were in Stage 2, 0% (0/16) in Stage 3A, 8.3% (1/12) in Stage 3B, 0% (0/16) in Stage 4, and 66.7% (8/12) in Stage 5. In patients with dysregulated RRDs, 14.7% (14/95) were in Stage 2, 15.7% (15/95) were in Stage 3A, 37.9% (36/95) in Stage 3B, 22.1% (21/95) in Stage 4, and 9.5% (9/95) in Stage 5 (P<0.001).

CONCLUSIONS

There are significant morphologic differences between regulated and dysregulated RRDs using SS-OCT. ORCs are present in almost all dysregulated cases but in a minority of regulated cases and they are an independent predictor of RPE-photoreceptor regulation status. Demographic and clinical features differentiate regulated and dysregulated RRD and understanding these differences has significant implications for optimal management and postoperative outcomes.

Changes of optical coherence tomographic hyperreflective foci in rhegmatogenous retinal detachment patients after successful surgery

PURPOSE

To assess the changes of hyperreflective foci (HRF) in rhegmatogenous retinal detachment (RRD) patients after successful reattachment surgery.

METHODS

Twenty-nine macula-off RRD eyes with successful reattachment surgery were retrospectively analyzed. Optical coherence tomography (OCT) was used to image macular regions and measure HRF in outer retina and inner retina at 0.5, 1, 3, 6, 12 months after surgery. The relationships between HRF and photoreceptor layer status, visual outcomes were evaluated.

RESULTS

After retinal reattachment, HRF mainly distributed at the location where external limiting membrane (ELM) or inner and outer segment (IS/OS) line was disrupted. The HRF numbers in outer and inner retina were greater in eyes with discontinuous IS/OS line than eyes with continuous IS/OS line (all p<0.05). In the outer retina,  HRF increased in the initial three months after retinal reattachment, and then decreased gradually after 3 months (p<0.05). The HRF number in the outer retina at postoperative 0.5 months was associated with favorable visual outcomes at 6 and 12 months (r=-0.487,  p =0.025; r=-0.626,  p=0.005, respectively), nevertheless, the HRF number at 3 months was correlated with poor visual results at 6 and 12 months (r=0.441,  p =0.017; r=0.477,  p=0.019, respectively).

CONCLUSION

HRF mainly occurred near the site where ELM or IS/OS line was injured after retinal reattachment. In the outer retina, the number of HRF gradually increased in the first 3 months and then gradually decreased. The early appearance of HRF in the outer retina was associated with a good visual prognosis, while the late appearance may suggest a less favorable visual outcome.

Persistent subfoveal fluid in pneumatic retinopexy versus pars plana vitrectomy for rhegmatogenous retinal detachment: posthoc analysis of the PIVOT randomised trial

PURPOSE

To assess the incidence of persistent subfoveal fluid (PSFF) in pneumatic retinopexy (PnR) versus pars plana vitrectomy (PPV) following rhegmatogenous retinal detachment (RRD) repair and to determine its association with functional outcomes.

METHODS

Posthoc analysis of the PIVOT randomised trial. Eyes with gradable en face and cross-sectional spectral-domain optical coherence tomography (SD-OCT) scans at 1-2 months postoperatively were included. Primary outcome was the proportion of patients with PSFF following PnR versus PPV at 1-2 months postoperatively. Secondary outcomes included association of PSFF with Early Treatment Diabetic Retinopathy Study (ETDRS) letter score at 3, 6 and 12 months and metamorphopsia score (MCHARTs) at 12 months.

RESULTS

Of 176 participants enrolled in PIVOT, 158 (89.8%) had gradable SD-OCT scans. Intergrader agreement was 0.870 (Cohen's kappa). The incidence of PSFF was 16% (13/81) following PnR and 10.4% (8/77) following PPV (p=0.298; OR=1.65, 95% CI 0.64 to 4.23). Median ETDRS score at 3 months postoperatively between eyes with and without PSFF was 71 (IQR=58-78) and 78 (IQR=70-84), respectively (difference=7 letters, p=0.037), with no significant difference at subsequent 6-month and 12-month visits. Median metamorphopsia scores in patients with versus without PSFF were: horizontal: 0.1 (IQR=0-0.3) vs 0 (IQR=0-0.2) (difference=0.1, p=0.228) and vertical: 0.25 (IQR=0-0.4) vs 0 (IQR=0-0.2) (difference=0.25, p=0.148), respectively.

CONCLUSIONS

There was no significant difference in the incidence of PSFF in eyes undergoing PnR versus PPV for RRD. The presence of PSFF at 1-2 months postoperatively was associated with worse ETDRS letter score at 3 months, but there was no difference at 1 year.

TRIAL REGISTRATION NUMBER

NCT01639209.

En Face OCT in Diagnosis of Persistent Subretinal Fluid and Outer Retinal Folds after Rhegmatogenous Retinal Detachment Repair

PURPOSE

To evaluate the role of en face OCT as a diagnostic tool for the detection of persistent subretinal fluid (PSRF) and outer retinal folds (ORFs) after successful rhegmatogenous retinal detachment (RRD) repair.

DESIGN

Observational post hoc analysis of 2 prospective surgical trials.

PARTICIPANTS

All patients with gradable (signal strength ≥ 5 and no segmentation error) 6 × 6-mm² macular cube scans obtained using spectral-domain OCT (Carl Zeiss Meditec) between 1 and 2 months after surgery were included in this study.

METHODS

The scans were assessed for the presence or absence of PSRF or ORFs using en face OCT and cross-sectional B scans by 2 masked graders, with any disagreements adjudicated by a third senior masked grader.

MAIN OUTCOME MEASURES

The sensitivity, specificity, and predictive accuracy (using area under the curve [AUC]) of en face OCT were compared with those of cross-sectional OCT, which is considered the gold standard.

RESULTS

Two hundred twenty-three patients were included in this study. The Cohen kappa between the graders in the diagnosis of PSRF and ORFs using en face OCT was 0.84 and 0.86, respectively. The sensitivity of en face OCT was 100% (95% confidence interval [CI], 100%-100%) in the diagnosis of PSRF and 98.8% (95% CI, 96.5%-101.1%) in the diagnosis of ORFs. Similarly, the specificity of en face OCT was 98.7% (95% CI, 96.8%-100.5%) and 84.2% (95% CI, 78.1%-90.2%) in the diagnosis of PSRF and ORFs, respectively. The AUC was 0.99 for PSRF and 0.91 for ORFs.

CONCLUSIONS

En face OCT has good sensitivity, specificity, and predictive accuracy (using AUC) in the diagnosis of PSRF and ORFs. En face OCT is an efficient screening tool for postoperative anatomic abnormalities, such as PSRF and ORFs, after RRD repair.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Outer Retinal Corrugations in Rhegmatogenous Retinal Detachment: The Retinal Pigment Epithelium-Photoreceptor Dysregulation Theory

PURPOSE

Outer retinal folds occur when outer retinal corrugations (ORCs) persist after retinal reattachment with worse functional outcomes. We investigate the pathophysiology of ORCs in vivo.

DESIGN

Prospective cohort study.

METHODS

Patients with rhegmatogenous retinal detachment (RRD) presenting to St. Michael's Hospital, Toronto, Ontario, Canada, between August 2020 and February 2022 were assessed with swept-source optical coherence tomography (SS-OCT) and ultra-widefield SS-OCT for ORCs. Clinical characteristics of eyes with/without ORCs were compared. Mathematical models were used to deduce mechanical properties leading to ORCs.

RESULTS

Sixty-six patients were included. More than half (60.6%, 40/66) were fovea-off and 48.4% (32/66) had ORCs at presentation. All eyes (32/32) with ORCs had retinal pigment epithelium (RPE)-photoreceptor dysregulation for at least 2 days, defined as loss of RPE control with acute, progressive, and extensive RRDs. In all (34/34) eyes without ORCs the RPE was in relative control of the subretinal space with nonprogressive subclinical or small localized or resolving RRDs, or with RPE-photoreceptor dysregulation for fewer than 2 days. Mathematical models indicate that a modulus of elasticity of the outer retina relative to the inner retina of 0.05 to 0.5 leads to ORCs.

CONCLUSIONS

ORCs develop with (1) acute exposure of subretinal space to liquified vitreous, (2) for >2 days, that (3) overwhelms RPE capacity, leading to progressive and extensive RRD. Mathematical models suggest that a reduction in the modulus of elasticity of the outer retina occurs such that intrinsic compressive forces, likely related to progressive outer retinal hydration and lateral expansion, lead to ORCs. Understanding the pathophysiology of ORCs has implications for management.

Optimizing Retinal Thermofusion in Retinal Detachment Repair: Achieving Instant Adhesion without Air Tamponade

PURPOSE

Rhegmatogenous retinal detachment repair by intraoperative sealing of the tear without a tamponade agent should enable faster restoration of vision and resumption of normal activities. It avoids the need for further surgery in the case of silicone oil endotamponade. This study evaluated the retinal thermofusion (RTF) retinopexy method of subretinal space dehydration before photocoagulation to create an instantaneous intraoperative retina reattachment in a preclinical model.

DESIGN

Preclinical study.

PARTICIPANTS

Twenty Dutch Belt, pigmented rabbits that underwent RTF repair after experimental retinal detachment.

METHODS

This ex vivo model quantified adhesion force between the retina and underlying retinal pigment epithelium and choroid after treatment of 1 retinal edge using postmortem porcine or human retina (6 × 12 mm). We compared (1) control, (2) laser photocoagulation alone, (3) dehydration alone, and (4) dehydration followed by photocoagulation (RTF). Optimized parameters for RTF were then applied in the in vivo rabbit model of retinal detachment. Animals were followed up for 14 days.

MAIN OUTCOME MEASURES

For this ex vivo model, we measured adhesion force and related this to tissue temperature. For the in vivo study, we assessed retinal attachment using funduscopy and histologic analysis.

RESULTS

The ex vivo model showed that RTF repair produced significantly higher adhesion force than photocoagulation alone independent of dehydration method: warm (60° C) high airflow (50-70 ml/minute) or using laser wavelengths targeting water absorption peaks (1470 or 1940 nm) with coaxial low airflow (10-20 ml/minute). The latter approach produced a smaller footprint of dehydration. Application of RTF (1940-nm laser with coaxial airflow) in an in vivo retinal detachment model in rabbit eyes resulted in immediate retinal adhesion, achieving forces similar to those in the ex vivo experiments. Retinal thermofusion repair resulted in stable reattachment of the retina over the 2-week follow-up period.

CONCLUSIONS

We showed that a short preliminary dehydrating laser treatment of a retinal tear margin before traditional laser photocoagulation creates an immediate intraoperative waterproof retinopexy adhesion independent of tamponade and a wound-healing response. This approach potentially will allow rapid postoperative recovery regardless of the tear location and improved vision.

Optical Coherence Tomography Findings in Rhegmatogenous Retinal Detachment: A Systematic Review

Rhegmatogenous retinal detachment is a sight-threatening condition that may lead to blindness if left untreated. Surgical treatments may vary and are tailored to a single patient. Anatomical and functional results may vary, due to factors that are currently under study. Optical coherence tomography (OCT) allows a detailed visualization of the retinal structure. Some studies have been performed using OCT on eyes with retinal detachment. We performed a review on the subject. Several data have been obtained using different OCT applications. Some alterations may represent potential biomarkers since they are associated with visual and anatomical prognoses. Increased knowledge on the subject may be helpful to choose among different surgical strategies and endotamponades. More research on the topic is needed.

Evaluation of Subretinal fluid Drainage Techniques during Pars Plana Vitrectomy for Primary Rhegmatogenous Retinal Detachment - ELLIPSOID study

PURPOSE

To compare visual acuity and photoreceptor integrity following vitrectomy (PPV) with drainage from the peripheral retinal break(s) (PRB) vs. posterior retinotomy (PR) vs. perfluorocarbon liquid (PFCL) for macula-off rhegmatogenous retinal detachment (RRD).

DESIGN

Retrospective consecutive interventional comparative clinical study.

METHODS

300 consecutive patients (300 eyes) with primary macula-off RRD underwent 23-gauge PPV with SRF drainage through 1) PRB (n=100), 2) PR (n=100), or 3) with PFCL (n=100). Visual acuity and SD-OCT were performed preoperatively and at 3, 6, and 12 months postoperatively. Primary outcomes were visual acuity and discontinuity of the external limiting membrane, ELM; ellipsoid zone, EZ; interdigitation zone, IDZ; and retinal pigment epithelium, RPE at 1-year.

RESULTS

Baseline characteristics were similar. Single-operation reattachment rates were: PRB 86%; PR 85%; PFCL 83%,p=0.9. Mean(±SD) logMAR visual acuity at 1-year was greater with PRB and PR compared to PFCL (PRB=0.6±0.5;PR=0.7±0.6;PFCL=0.9±0.6,p=0.002). There was an association between drainage technique and discontinuity of the ELM (PRB 26%,PR 24%,PFCL 44%,p=0.001), EZ (PRB 29%,PR 31%,PFCL 49%,p<0.001) and IDZ (PRB 43%,PR 39%,PFCL 56%, p=0.004). There was an association between drainage technique and risk of cystoid macular edema (CME) (PRB 28%,PR 39%,PFCL 46%,p=0.003) and ERM (PRB 64%,PR 90%,PFCL 61%,P<0.001).

CONCLUSIONS

PFCL-assisted drainage is associated with worse visual acuity and greater risk of outer retinal band discontinuity and CME compared with PRB or PR. PR had a greater risk of ERM compared with PRB and PFCL. PRB had the best outcomes overall. Drainage technique may impact long-term anatomic and functional outcomes.

Retinal Displacement Following Rhegmatogenous Retinal Detachment: A Systematic Review and Meta-Analysis

Retinal displacement following rhegmatogenous retinal detachment (RRD) repair is an important consideration when assessing the integrity of reattachment, with potential implications on functional outcomes. There are limited data comparing various surgical techniques. We conducted a review of retinal displacement following RRD repair through October 2021, finding twenty-one studies encompassing 1258 unique eyes. Outcome measures included the frequency of retinal displacement, visual acuity, metamorphopsia, and displacement direction. A meta-analysis was performed with data reported as risk ratios or mean difference and 95% confidence intervals. Retinal displacement was found in 35±20% of RRD repairs. Scleral buckle (SB) without tamponade had the lowest rate of retinal displacement (9.60 [2.01-45.95], p=0.005), followed by pneumatic retinopexy (PnR) and finally pars plana vitrectomy (PPV). Silicone oil may reduce risk of displacement following PPV compared to gas (2.16 [1.22-3.83], p=0.009), as may immediate face-down positioning for 2 hours. Retinal displacement following PPV occurred in the downward direction in 92±14% of cases and does not appear to significantly impact visual acuity (0.05 [-0.21-0.31 p=0.70), although it may increase distortion. SB, PnR, PPV with silicone oil, and immediate face-down positioning are likely associated with less retinal displacement. Additional prospective studies are required to increase the certainty of these findings.

Physiology of retinal reattachment in humans: Swept source optical coherence tomography imaging data supporting a novel staging system

This article presents high-resolution swept source optical coherence tomography (SS-OCT) imaging data used to describe the physiology of retinal reattachment in humans. SS-OCT imaging was performed at baseline and every 2 h for the first 6 h and at frequent intervals thereafter up to 6 weeks following the injection of intravitreal gas in eyes undergoing pneumatic retinopexy for rhegmatogenous retinal detachment. Imaging data presented in this article is related to the research paper titled “Real-Time in Vivo Assessment of Retinal Reattachment in Humans using Swept-Source Optical Coherence Tomography” (Bansal et al., 2021). SS-OCT images were assessed longitudinally and used to devise a novel staging system that describes the physiology of retinal reattachment. Multiple examples of each stage and the transition from one stage to the next are provided. SS-OCT images were also assessed to determine the timing associated with each stage, and the anatomic abnormalities, such as outer retinal folds and subretinal fluid blebs that occured as a result of delayed progression through certain stages.

Pneumatic retinopexy: an update

Pneumatic retinopexy (PR) is a minimally invasive, non-incisional procedure for repairing uncomplicated rhegmatogenous retinal detachment. It consists of an intravitreal gas injection followed by the maintenance of a postoperative head position and the use of laser or cryopexy to seal the retinal breaks. It was initially indicated for a single or a group of retinal breaks no larger than 1 clock hour involving the superior 8 clock hours in phakic eyes with no proliferative vitreoretinopathy. We aim to perform a narrative review on pneumatic retinopexy since the last major review of 2008, based on a Medline search up to June 20 2021 using multiple search words including pneumatic retinopexy, pneumoretinopexy, retinal detachment, and pars plana vitrectomy. Indications for PR have been expanded and include pseudophakic eyes, eyes with mild PVR, and even breaks in the inferior fundus. Depending on the case selection, PR has a single-operation success rate ranging from 45 to 80%. Despite the lower single operation success rate, the functional outcomes of those eyes repaired successfully by primary PR exceed those of scleral buckling (SB) and pars plana vitrectomy (PPV). Best corrected visual acuity, metamorphopsia scores, mental health scores, and vision-related functioning scores were all better in PR-treated eyes compared to PPV-treated eyes. PR should be strongly considered for eligible patients with a primary uncomplicated rhegmatogenous retinal detachments.

Outer Retinal Folds Following Pars Plana Vitrectomy vs Pneumatic Retinopexy for Retinal Detachment Repair: Post Hoc Analysis from PIVOT

PURPOSE

To assess the incidence of post-operative outer retinal folds (ORFs) in pars plana vitrectomy (PPV) vs pneumatic retinopexy (PnR) following rhegmatogenous retinal detachment (RRD) repair and to determine the association of ORFs with functional outcomes at 1 year.

DESIGN

Randomized controlled trial PARTICIPANTS: Patients with primary macula-off RRD meeting PIVOT trial criteria randomly assigned to PPV vs PnR.

METHODS

Post-hoc analysis of the PIVOT trial. Incidence and quantitative morphological features of ORFs were assessed with en face and cross-sectional OCT at 1 month post-operatively by two masked graders. ETDRS letter score and quantitative metamorphopsia were measured at 1 year.

MAIN OUTCOME MEASURES

Proportion of patients with ORFs following PPV vs PnR at 1 month post-operatively. Secondary outcomes include the association of ORFs with visual acuity (ETDRS letter score) and metamorphopsia (M-CHARTS) at 12 months post-operatively.

RESULTS

Eighty-eight of the 176 participants enrolled in PIVOT were macula-off RRD. 94.3% (83/88) of these macula-off eyes had month 1 post-operative OCT scans that were gradable, 93.2% (41/44) in the PPV group and 95.5% (42/44) in the PnR group. The incidence of ORFs formation was 34.1% (14/41) in the PPV group and 14.3% (6/42) in the PnR group (p=0.034). ETDRS letter score at 1 year was 65.7±6.6 letters in patients with ORFs versus 75.1±1.4 letters in those without ORFs (difference=9.4 letters, 95% CI=7.5-11.3, p=0.047). Among patients in the PPV group only, mean ETDRS letter score at 1 year in patients with ORFs was 62.8 ± 24.7 letters compared to 75.4 ± 9.2 letters in patients without ORF formation (difference=12.6 letters, 95% CI=0.05-24.59, p=0.04). Horizontal and vertical metamorphopsia scores were similar in patients with vs without ORFs: horizontal: 0.35 ± 0.12 versus 0.29 ± 0.07 (difference=0.06, 95% CI=0.01-0.11, p=0.69) and vertical: 0.25±0.07 versus 0.29±0.07 (difference=0.04, 95%CI=0-0.08, p=0.60) respectively. There was a negative correlation between the closest distance of the ORFs from the fovea and the vertical metamorphopsia score (r=-0.507, p=0.045).

CONCLUSIONS

There is a greater risk of developing ORFs following PPV compared to PnR for RRD. ORFs at 1 month are associated with significantly worse ETDRS visual acuity letter score at 1 year.