Interpretation of Subretinal Fluid Using OCT in Intermediate Age-Related Macular Degeneration

NONEXUDATIVE INTRARETINAL FLUID IN INTERMEDIATE AGE-RELATED MACULAR DEGENERATION

BACKGROUND

To describe the occurrence of nonexudative intraretinal fluid (IRF) in intermediate age-related macular degeneration.

METHODS

A retrospective study was designed to include consecutive cases with intermediate age-related macular degeneration associated with IRF. A multimodal imaging approach was used to confirm diagnosis of IRF in intermediate age-related macular degeneration. Multimodal imaging included color fundus photograph, fundus autofluorescence, fluorescein angiography, indocyanine green angiography, optical coherence tomography, and optical coherence tomography angiography.

RESULTS

Ten eyes of 10 patients (2 male and 8 female patients, ages 68-80 years) showing IRF in intermediate age-related macular degeneration were included in the study. The mean best-corrected visual acuity was 20/40 Snellen equivalent. Multimodal imaging including fluorescein angiography/indocyanine green angiography and optical coherence tomography demonstrated the absence of macular neovascularization in all cases; optical coherence tomography-angiography did not detect any abnormal flow signal associated with IRF. Seven of 10 patients developed IRF in correspondence of pigment epithelium detachment. Three of 10 patients presented IRF in correspondence of an area of nascent geographic atrophy.

CONCLUSION

Nonexudative intraretinal fluid in intermediate age-related macular degeneration is a novel, distinctive feature that is characterized by the presence of IRF with no evidence of macular neovascular lesions. The authors described different phenotypes of IRF in intermediate age-related macular degeneration. The definite diagnosis of this condition requires further studies with thorough application of multimodal imaging.

Subretinal hyperreflective material in retinal and chorioretinal disorders: A comprehensive review

Subretinal hyperreflective material (SHRM) is a common and remarkable optical coherence tomography (OCT) biomarker whose importance is emerging in several retinal and chorioretinal diseases, including age-related macular degeneration, central serous chorioretinopathy, polypoidal choroidal vasculopathy, pathologic myopia, posterior uveitis, vitelliform lesions and macular dystrophies, and rarer disorders. Multimodal imaging, also thanks to the introduction of OCT angiography, allowed a deeper characterisation of SHRM components and its morphological changes after treatment, suggesting its usefulness in clinical practice. We discuss and summarize the nature, multimodal imaging characteristics, and prognostic and predictive significance of SHRM in the different retinal and choroidal disorders in which it has been described.

Non-neovascular fluid in age-related macular degeneration: observe-and-extend regimen in a case-series study

OBJECTIVE

To describe the course of non-neovascular fluid in age-related macular degeneration (AMD) after anti-vascular endothelial growth factor (anti-VEGF) therapy or after observation without injections.

DESIGN

Retrospective case series.

METHODS

AMD eyes with macular drusen and (or) drusenoid pigment epithelial detachment associated with non-neovascular fluid were included. Optical coherence tomography (OCT) angiography was performed in all eyes to exclude the presence of macular neovascularization. Subretinal fluid (SRF) was measured to determine the response after anti-VEGF therapy and after observation without injections.

RESULTS

Ten eyes of 9 patients with intermediate AMD and SRF were studied over a median period of 59.5 months (range, 7-128 months). Six patients (6 eyes) had a history of anti-VEGF therapy. Median follow-up off injections was 13.5 months (range, 4-44 months). SRF thickness remained stable and unchanged during the follow-up off injections in all eyes (n = 6) with prior injection and in all eyes (n = 4) that had never been injected. Six eyes developed complete retinal pigment epithelial (RPE) and outer retinal atrophy, and 1 eye developed incomplete RPE and outer retinal atrophy. All eyes exhibited at least 2 OCT biomarkers associated with a high risk for progression to atrophy.

CONCLUSION

This study provides preliminary data regarding the progression of non-neovascular fluid in AMD with or without anti-VEGF injections. A possible mechanism for fluid development may be related to RPE pump impairment. Distinguishing neovascular versus non-neovascular fluid using multimodal imaging, including OCT angiography, is essential to avoid unnecessary anti-VEGF therapy. An observe-and-extend regimen may be considered in AMD eyes with non-neovascular fluid.

MULTIMODAL IMAGING OF BILATERAL IDIOPATHIC MULTIFOCAL RETINAL PIGMENT EPITHELIAL DETACHMENTS IN YOUNG PATIENTS

PURPOSE

The aim of this study was to describe two cases of multiple epithelial detachments (pigment epithelial detachments [PEDs]) occurring in otherwise young, healthy patients.

METHODS

The medical and imaging records of two cases were reviewed retrospectively.

RESULTS

Multiple serous nonvascularized PEDs were present in two young, healthy patients who underwent multimodal imaging. The first patient, a 38-year-old woman, was incidentally found to have a visual acuity of 20/20 in both eyes and multiple bilateral PEDs. Imaging and a systemic work-up was negative for secondary causes, and at 36 months, vision remained stable although some of the PEDs had coalesced. The second patient, a 32-year-old woman, presented with distortion and perceived scotomas in both eyes progressive over the course of 2 years. The visual acuity was 20/20, and multimodal imaging confirmed the presence of bilateral PEDs.

CONCLUSION

Bilateral idiopathic multifocal retinal PEDs in otherwise healthy young adults is a rare condition. Longer term follow-up is needed to evaluate secondary complications and visual outcomes.

SUBRETINAL FLUID ASSOCIATED WITH DRUSENOID PIGMENT EPITHELIAL DETACHMENT

PURPOSE

To analyze the clinical characteristics of drusenoid pigment epithelial detachment (PED) with subretinal fluid (SRF) and to evaluate the impact of SRF on the long-term visual and anatomical outcomes.

METHODS

Forty-seven eyes with drusenoid PED (47 patients) who completed >24 months of follow-up were retrospectively analyzed. Intergroup comparisons of the visual and anatomical outcomes with and without SRF were made.

RESULTS

The mean duration of follow-up was 32.9 ± 18.7 months. The group with drusenoid PED with SRF (14 eyes) showed significantly higher PED height (468 ± 130 µ m vs. 313 ± 88 µ m, P < 0.001), larger PED diameter (2,328 ± 953 µ m vs. 1,227 ± 882 µ m, P < 0.001), and larger PED volume (1.88 ± 1.73 mm 3 vs. 1.12 ± 1.35 mm 3 , P = 0.021) than that in the group with drusenoid PED without SRF (33 eyes) at baseline. No significant intergroup difference was found regarding the best-corrected visual acuity at the final visit. In addition, the incidence of complete retinal pigment epithelial and outer retinal atrophy (cRORA; 21.4%) and the development of macular neovascularization (MNV; 7.1%) for the group with drusenoid PED with SRF showed no difference compared with those (39.4% for cRORA development and 9.1% for MNV development) with drusenoid PED without SRF.

CONCLUSION

The size, height, and volume of drusenoid PED were associated with the development of SRF. The SRF in drusenoid PED did not affect the visual prognosis or the development of macular atrophy during long-term follow-up.

Volume Rendering of Deep Retinal Age-Related Microvascular Anomalies

PURPOSE

To characterize and distinguish non-neovascular deep retinal age-related microvascular anomalies (DRAMA) from type 3 macular neovascularization (MNV) using volume rendering of OCT and OCT angiography (OCTA).

DESIGN

Retrospective, consecutive case series.

SUBJECTS

Consecutive patients with age-related macular degeneration (AMD) exhibiting de novo non-neovascular abnormalities within the deep vascular plexus (DCP), as detected using high-resolution (High-Res) spectral-domain (SD) and swept-source (SS) OCT or OCTA. Patients with retinal vascular alterations attributable to other disease entities were excluded.

METHODS

Complete ophthalmic examination and multimodal imaging, including confocal fundus photography (CFP), SD-OCT, High-Res SD-OCT and OCTA, and volume-averaged SS-OCTA. The volume renderings of High-Res OCTA and averaged SS-OCTA were used to analyze capillary abnormalities and inflow or outflow connectivity pathways.

MAIN OUTCOME MEASURES

The primary outcomes were the characteristics of capillary abnormalities (number, size, shape, reflectivity, and location) and inflow or outflow connectivity pathways. The secondary outcomes were nearby changes in CFP and structural OCT (hyperreflective foci [HRF], outer retinal atrophy, and retinal pigment epithelium [RPE] atrophy).

RESULTS

From 8 eyes of 8 patients, 2 subtypes of DRAMA were identified: small-diameter perifoveal capillary dilations with hyperreflective walls within the inner nuclear layer (type 1, n = 4) and vascular outpouchings, typically multiple, extending posteriorly into the Henle fiber layer, with reflectivity similar to adjacent normal retinal capillaries (type 2, n = 10). Four eyes had both subtypes of DRAMA. The 3-dimensional visualization of OCTA data demonstrated DRAMA corresponding to the dilations of DCP capillaries without direct inflow or outflow connections to the superficial plexus. Fundus photographs showed circular red dots in 3 eyes, all corresponding to type 1 DRAMA. In all the cases, DRAMA colocalized with HRF. No lesions were found anterior to the areas of the RPE or outer retina atrophy. Asymptomatic intraretinal exudation varied through a follow-up duration of up to 6 years, with no lesions progressing to type 3 MNV.

CONCLUSIONS

In eyes with non-neovascular AMD, DRAMA include 2 types of capillary dilations occurring without the remodeling of the surrounding vascular network. Deep retinal age-related microvascular anomalies can resemble microvascular changes due to other causes and can masquerade as type 3 MNV. Mild intraretinal exudation can vary during follow-up, without progression to type 3 MNV.

Effect of Residual Retinal Fluid on Visual Function in Ranibizumab-Treated Neovascular Age-Related Macular Degeneration

PURPOSE

To investigate the relationship between retinal fluid and vision in ranibizumab-treated patients with neovascular age-related macular degeneration (nAMD).

DESIGN

Clinical cohort study using post hoc analysis of clinical trial data.

METHODS

We assessed data from HARBOR (NCT00891735), a phase III, randomized, controlled trial. We reviewed 917 patients ≥50 years of age with subfoveal nAMD associated with subretinal (SRF) and/or intraretinal fluid (IRF) at baseline, screening, or week 1. The intervention was intravitreal ranibizumab 0.5 or 2.0 mg (all treatment arms pooled). Outcomes included mean best-corrected visual acuity (BCVA) and BCVA change from baseline at months (M) 12 and 24 evaluated by the presence/absence of SRF and/or IRF.

RESULTS

Baseline BCVA was higher with residual vs resolved SRF at M12 (mean [95% confidence interval {CI}] 58.8 letters [57.2-60.4] vs 53.5 [52.4-54.5]) and M24 (59.3 letters [57.8-60.8] vs 53.5 [52.5-54.5]). Mean BCVA change (adjusted for baseline) to M12 was greater with residual vs resolved SRF (mean difference [95% CI], +2.4 letters [+0.1 to +4.7]), but lower with residual vs resolved IRF (-3.5 letters [-5.8 to -1.2]). Eyes with residual SRF (no IRF) exhibited the largest mean BCVA gains (M12, +14.1 letters; M24, +13.2 letters), followed by resolved SRF/IRF (M12, +10.6 letters; M24, +10.0 letters), residual SRF/IRF (M12, +7.2 letters; M24, +8.5 letters), and residual IRF only (M12, +5.5 letters; M24, +3.6 letters).

CONCLUSIONS

Vision outcomes (adjusted for baseline BCVA) through M24 were better in ranibizumab-treated eyes with residual vs resolved SRF, and worse with residual vs resolved IRF. Presence of residual retinal fluid requires a more complex and nuanced assessment and interpretation in the context of nAMD management.

Biomarkers for Nonexudative Age-Related Macular Degeneration and Relevance for Clinical Trials: A Systematic Review

TOPIC

The purpose of the review was to identify structural, functional, blood-based, and other types of biomarkers for early, intermediate, and late nonexudative stages of age-related macular degeneration (AMD) and summarize the relevant data for proof-of-concept clinical trials.

CLINICAL RELEVANCE

AMD is a leading cause of blindness in the aging population, yet no treatments exist for its most common nonexudative form. There are limited data on the diagnosis and progression of nonexudative AMD compared to neovascular AMD. Our objective was to provide a comprehensive, systematic review of recently published biomarkers (molecular, structural, and functional) for early AMD, intermediate AMD, and geographic atrophy and to evaluate the relevance of these biomarkers for use in future clinical trials.

METHODS

A literature search of PubMed, ScienceDirect, EMBASE, and Web of Science from January 1, 1996 to November 30, 2020 and a patent search were conducted. Search terms included "early AMD," "dry AMD," "intermediate AMD," "biomarkers for nonexudative AMD," "fundus autofluorescence patterns," "color fundus photography," "dark adaptation," and "microperimetry." Articles were assessed for bias and quality with the Mixed-Methods Appraisal Tool. A total of 94 articles were included (61,842 individuals).

RESULTS

Spectral-domain optical coherence tomography was superior at highlighting detailed structural changes in earlier stages of AMD. Fundus autofluorescence patterns were found to be most important in estimating progression of geographic atrophy. Delayed rod intercept time on dark adaptation was the most widely recommended surrogate functional endpoint for early AMD, while retinal sensitivity on microperimetry was most relevant for intermediate AMD. Combinational studies accounting for various patient characteristics and machine/deep-learning approaches were best suited for assessing individualized risk of AMD onset and progression.

CONCLUSION

This systematic review supports the use of structural and functional biomarkers in early AMD and intermediate AMD, which are more reproducible and less invasive than the other classes of biomarkers described. The use of deep learning and combinational algorithms will gain increasing importance in future clinical trials of nonexudative AMD.

Intraretinal, sub-retinal, and sub-retinal pigmented epithelium fluid in non-exudative age-related macular degeneration: follow-up with OCT imaging

BACKGROUND/OBJECTIVES

To evaluate the presence and evolution of fluid in non-exudative age-related macular degeneration (AMD) through serial OCT.

SUBJECTS/METHODS

A retrospective analysis of eyes with non-exudative AMD with a minimum of 4 year follow-up was done. Parameters including intraretinal fluid (IRF), subretinal fluid (SRF), and sub-retinal pigment epithelium (RPE) fluid (SRPEF); subfoveal choroidal thickness (SFCT) and type of drusen were evaluated using optical coherence tomography (OCT) scans at baseline and follow up visits.

RESULTS

Seventy-two eyes (in 63 patients) were followed up for an average of 5.83 ± 2.17 years. A total of 26/72 (36%) and 29/65 (52%) of the non-exudative eyes had fluid during baseline and the last visit. Seven eyes (10%) out of 72 eyes converted into exudative AMD or neo-vascular AMD (nAMD) during the study period. SRPEF at baseline was most common fluid location for non-exudative eyes that eventually converted to nAMD.

CONCLUSION

Non-exudative fluid including IRF, SRF, and SRPEF is seen in patients with non-exudative AMD with increasing incidence during long term follow-up.

Serous business: Delineating the broad spectrum of diseases with subretinal fluid in the macula

A wide range of ocular diseases can present with serous subretinal fluid in the macula and therefore clinically mimic central serous chorioretinopathy (CSC). In this manuscript, we categorise the diseases and conditions that are part of the differential diagnosis into 12 main pathogenic subgroups: neovascular diseases, vitelliform lesions, inflammatory diseases, ocular tumours, haematological malignancies, paraneoplastic syndromes, genetic diseases, ocular developmental anomalies, medication-related conditions and toxicity-related diseases, rhegmatogenous retinal detachment and tractional retinal detachment, retinal vascular diseases, and miscellaneous diseases. In addition, we describe 2 new clinical pictures associated with macular subretinal fluid accumulation, namely serous maculopathy with absence of retinal pigment epithelium (SMARPE) and serous maculopathy due to aspecific choroidopathy (SMACH). Differentiating between these various diseases and CSC can be challenging, and obtaining the correct diagnosis can have immediate therapeutic and prognostic consequences. Here, we describe the key differential diagnostic features of each disease within this clinical spectrum, including representative case examples. Moreover, we discuss the pathogenesis of each disease in order to facilitate the differentiation from typical CSC.

Non-neovascular age-related macular degeneration with subretinal fluid

PURPOSE

To evaluate the various patterns of subretinal fluid (SRF) in eyes with age-related macular degeneration (AMD) in the absence of macular neovascularisation (MNV) and to assess the long-term outcomes in these eyes.

METHODS

This retrospective study included only eyes with non-neovascular AMD and associated SRF. Eyes with evidence of MNV were excluded. Spectral-domain optical coherence tomography (SD-OCT) was obtained at baseline and at follow-up, and qualitative and quantitative SD-OCT analysis of macular drusen including drusenoid pigment epithelial detachment (PED) and associated SRF was performed to determine anatomic outcomes.

RESULTS

Forty-five eyes (45 patients) were included in this analysis. Mean duration of follow-up was 49.7±36.7 months. SRF exhibited three different morphologies: crest of fluid over the apex of the drusenoid PED, pocket of fluid at the angle of a large druse or in the crypt of confluent drusen or drape of low-lying fluid over confluent drusen. Twenty-seven (60%) of the 45 eyes with fluid displayed collapse of the associated druse or drusenoid PED and 24 (53%) of the 45 eyes developed evidence of complete or incomplete retinal pigment epithelial and outer retinal atrophy.

CONCLUSION

Non-neovascular AMD with SRF is an important clinical entity to recognise to avoid unnecessary anti-vascular endothelial growth factor therapy. Clinicians should be aware that SRF can be associated with drusen or drusenoid PED in the absence of MNV and may be the result of retinal pigment epithelial (RPE) decompensation and RPE pump failure.

[Differential diagnosis of various types of fluids on the eye fundus in patients with age-related macular degeneration]

Age-related macular degeneration (AMD) is a leading cause of vision loss both worldwide and in Russia. A distinctive feature of the exudative form of AMD is the presence of choroidal neovascularization (CNV) as a result of pathological angiogenesis of the choroid. With the introduction of optical coherence tomography (OCT) - a non-invasive imaging technique - it has become possible to monitor CNV activity. In the development of CNV, OCT can reveal three types of fluid localization: intraretinal fluid (IRF), subretinal fluid, fluid under retinal pigment epithelium (RPE). Exudative IRF is characterized by the presence of round and/or oval space. This type of fluid is characterized by good response to anti-VEGF therapy. Degenerative IRF («cystoid degeneration») is characterized as a small, clearly defined hyporeflective spaces above the area with altered RPE not responding to anti-VEGF therapy. Thus, early diagnosis of AMD and detection of «new activity» after therapy with antivascular endothelial growth factor (anti-VEGF) by comparing distribution of the fluid in SD-OCT are critical to maintaining or restoring the best possible visual acuity in patients with this disease.

Age-related macular degeneration (AMD): More than meets the eye. The role of multimodal imaging in today's management of AMD-A review

Multimodal imaging (MMI) allows a more granular grading of age-related macular degeneration (AMD) disease severity, with many novel risk factors having been recently identified. With this imaging information, we are better able to counsel our patients with more accurate and individualized progression scenarios. MMI also allows identification of anatomical features that increase our understanding of disease processes involved in progression to late AMD. Treatment protocols for neovascular AMD (nAMD) depend largely on the optical coherence tomography (OCT) appearance to determine disease activity, which allows us to individualize treatment. In geographic atrophy (GA), new intervention trials require the ability to define the extent of GA, so that GA growth rate can be determined. This is achieved through fundus autofluorescence (FAF) imaging, which allows greater accuracy of border identification, as well as revealing FAF patterns predictive of growth rates. As we strive to bring interventions earlier in the disease course, OCT imaging provides an ability to identify the first signs of atrophy, which may serve as novel surrogate biomarkers for GA, thereby facilitating trials. In the future, the use of artificial intelligence (AI) to automatically identify relevant features on MMI could further enhance our ability to determine disease severity, predict progression and assist in identifying disease activity parameters to support clinical decision making when treating nAMD. Newer developments may allow frequent, remote capturing of images, reducing clinic visits, detecting progression and monitoring neovascular activity in-between clinic visits. Being aware of these new imaging insights in AMD, greatly enhance our clinical management of AMD.

Predicting conversion to wet age-related macular degeneration using deep learning

Progression to exudative 'wet' age-related macular degeneration (exAMD) is a major cause of visual deterioration. In patients diagnosed with exAMD in one eye, we introduce an artificial intelligence (AI) system to predict progression to exAMD in the second eye. By combining models based on three-dimensional (3D) optical coherence tomography images and corresponding automatic tissue maps, our system predicts conversion to exAMD within a clinically actionable 6-month time window, achieving a per-volumetric-scan sensitivity of 80% at 55% specificity, and 34% sensitivity at 90% specificity. This level of performance corresponds to true positives in 78% and 41% of individual eyes, and false positives in 56% and 17% of individual eyes at the high sensitivity and high specificity points, respectively. Moreover, we show that automatic tissue segmentation can identify anatomical changes before conversion and high-risk subgroups. This AI system overcomes substantial interobserver variability in expert predictions, performing better than five out of six experts, and demonstrates the potential of using AI to predict disease progression.

Prospective PED-study of intravitreal aflibercept for refractory vascularized pigment epithelium detachment due to age-related macular degeneration: morphologic characteristics of non-responders in optical coherence tomography

Purpose

The aim of this study was to investigate the outcomes of a fixed intravitreal aflibercept regimen in patients with vascular pigment epithelium detachment (vPED) secondary to age-related macular degeneration with refractory subretinal fluid.

Methods

A prospective, interventional case series involved 20 eyes of 20 patients with refractory subretinal fluid and vPED treated with at least three injections of intravitreal anti-VEGF prior to study inclusion. After study inclusion, patients were treated with three injections of intravitreal aflibercept 2 mg/0.05 mL monthly followed by injections every 8 weeks. Best-corrected visual acuity (BCVA) and spectral-domain optical coherence tomography (SD-OCT) were evaluated at all visits. Fluorescein angiography and indocyanine green angiography were performed at baseline and quarterly. Primary outcomes were effectivity of a fixed treatment as measured in change in BCVA, PED greatest linear diameter (GLD), and PED height from baseline to month 12. In an additional post hoc analysis, vPED patients were differentiated into two groups: (1) vPED lesions that showed persistence of subretinal fluid throughout 1 year of treatment and (2) vPED lesions that showed complete resolution of subretinal fluid at least at one of the monthly performed OCT volume scans. Reflectivity values were determined in the subretinal pigment epithelium (RPE) compartment in OCT scans at baseline, month 6 and 12.

Results

A total of 18 patients completed the study protocol. The mean age was 74.8 ± 10.6 years, and six patients were female. The median BCVA of all patients was 72.0 ± 8.0 EDTRS letters at baseline and 72.5 ± 9.5 EDTRS letters at 12-month follow-up (p = 0.7420). The median PED height in all patients as measured in the OCT images significantly decreased from 372.0 ± 140.0 μm to 149.0 ± 142.0 μm after 12 months of treatment (p = 0.0020). Persistent subretinal fluid was present at every OCT control in six patients (group 1). Twelve patients showed resolution of subretinal fluid at least at one OCT control (group 2). Reflectivity values in the sub-RPE compartment in OCT scans were 41.48 ± 4.48 (group 1) and 42.62 ± 12.34 (group 2) at baseline (p = 0.854) and 65.88 ± 6.74 and 50.87 ± 14.11 at month 12 (p = 0.038).

Conclusions

Intravitreal aflibercept in refractory vPED leads to a significant reduction in PED height and disease activity as well as preservation of BCVA over 1 year. Persistent subretinal fluid was present in PED lesions with high values of reflectivity under the RPE, suggesting both a diffusion barrier and an increasing fibrovascular maturization of the choroidal neovascularization.

Trial registration

ClinicalTrials.gov Identifier: NCT03370380

Increased serum proteins in non-exudative AMD retinas

The blood retinal barrier (BRB) closely regulates the retinal microenvironment. Its compromise leads to the accumulation of retinal fluid containing potentially harmful plasma components. While eyes with non-exudative age-related macular degeneration (AMD) were previously felt to have an intact BRB, we propose that the BRB in non-exudative AMD eyes may be subclinically compromised, allowing entry of retina-toxic plasma proteins. We test this hypothesis by measuring retinal levels of abundant plasma proteins that should not cross the intact BRB. Two cohorts of frozen, post mortem neurosensory retinas were studied by Western analysis. One cohort from Alabama had 4 normal controls and 4 eyes with various forms of AMD. Another cohort from Minnesota had 5 intermediate AMD eyes and 5 normals. Both cohorts were age/post mortem interval (PMI) matched. The non-exudative AMD retinas in the Alabama cohort had significantly higher levels of albumin and complement component 9 (C9) than normal controls. The positive control exudative AMD donor retina had higher levels of all but one serum protein. In both macular and peripheral neurosensory retina samples, intermediate AMD retinas in the Minnesota cohort had significantly higher levels of albumin, fibrinogen, IgG, and C9 than controls. Our results suggest that there may be moderate subclinical BRB leakage in non-exudative AMD. Potentially harmful plasma components including complement or iron could enter the neurosensory retina in AMD patients prior to advanced disease. Thus, therapies aiming to stabilize the BRB might have a role in the management of non-exudative AMD.

Tolerating Subretinal Fluid in Neovascular Age-Related Macular Degeneration Treated with Ranibizumab Using a Treat-and-Extend Regimen: FLUID Study 24-Month Results

PURPOSE

To test the hypothesis that tolerating some subretinal fluid (SRF) in patients with neovascular age-related macular degeneration (nAMD) treated with ranibizumab using a treat-and-extend (T&E) regimen can achieve similar visual acuity (VA) outcomes as treatment aimed at resolving all SRF.

DESIGN

Multicenter, randomized, 24-month, phase 4, single-masked, noninferiority clinical trial.

PARTICIPANTS

Participants with treatment-naïve active subfoveal choroidal neovascularization (CNV).

METHODS

Participants were randomized to receive ranibizumab 0.5 mg monthly until either complete resolution of SRF and intraretinal fluid (IRF; intensive arm: SRF intolerant) or resolution of all IRF only (relaxed arm: SRF tolerant except for SRF >200 μm at the foveal center) before extending treatment intervals. A 5-letter noninferiority margin was applied to the primary outcome.

MAIN OUTCOME MEASURES

Mean change in best-corrected VA (BCVA), and central subfield thickness and number of injections from baseline to month 24.

RESULTS

Of the 349 participants randomized (intensive arm, n = 174; relaxed arm, n = 175), 279 (79.9%) completed the month 24. The mean change in BCVA from baseline to month 24 was 3.0 letters (standard deviation, 16.3 letters) in the intensive group and 2.6 letters (standard deviation, 16.3 letters) in the relaxed group, demonstrating noninferiority of the relaxed compared with the intensive treatment (P = 0.99). Similar proportions of both groups achieved 20/40 or better VA (53.5% and 56.6%, respectively; P = 0.92) and 20/200 or worse VA (8.7% and 8.1%, respectively; P = 0.52). Participants in the relaxed group received fewer ranibizumab injections over 24 months (mean, 15.8 [standard deviation, 5.9]) than those in the intensive group (mean, 17 [standard deviation, 6.5]; P = 0.001). Significantly more participants in the intensive group never extended beyond 4-week treatment intervals (13.5%) than in the relaxed group (2.8%; P = 0.003), and significantly more participants in the relaxed group extended to and maintained 12-week treatment intervals (29.6%) than the intensive group (15.0%; P = 0.005).

CONCLUSIONS

Patients treated with a ranibizumab T&E protocol who tolerated some SRF achieved VA that is comparable, with fewer injections, with that achieved when treatment aimed to resolve all SRF completely.