Prevalence, characteristics, and pathogenesis of paravascular inner retinal defects associated with epiretinal membranes

Mechanical impact of epiretinal membranes on the retina utilizing finite element analysis

BACKGROUND AND OBJECTIVE

Epiretinal membrane (ERM) is a transparent membrane that forms on the surface of the neurosensory retina, causing tangential traction on the retinal surface, which may contribute to cell proliferation and contraction. Epiretinal membranes (ERMs) may be asymptomatic in some patients, while in others the membranes can progress, resulting in macular thickening and macular traction, thus distorting and inducing loss of central visual function and metamorphopsia. Currently, treatment options include follow-up or pars plana vitrectomy with an ERM peel, aiming to relieve the macular traction and improve vision and metamorphopsia. No specific criteria exist for predicting which patients might progress and need early surgery to improve and maintain good vision. The decision for surgery is based on the individual's symptoms and the physician's judgment. This study aimed to evaluate the mechanical impact in terms of stress and deformations of the ERM and to qualitatively compare them with the clinical progression of fovea thickening observed through optical coherence tomography (OCT) images.

METHODS

Numerical simulation on a three-dimensional geometrical retina and ERM model was applied to isolate factors that can be used to predict its progression and prognosis. OCT images of 14 patients with ERM were used to derive the fovea thickness progression before and after vitrectomy surgery with ERM peeling.

RESULTS

The results clearly show that the increase in ERM contractility level increases the developed stress at the fovea, which spreads and advances toward its base. The highest stress level (2.1 kPa) was developed at the highest and asymmetric contractility, producing non-uniform distributed deformations that distort the fovea structure.

CONCLUSIONS

These findings imply that high and asymmetric ERM contractility should be evaluated clinically as a factor that might signal the need for early vitrectomy surgery to avoid irreversible visual loss. Moreover, the OCT images revealed that in some cases, the thickness of the fovea indeed remains high, even after ∼12 months postoperatively, which also indicates that the deformation of the fovea in these cases is irreversible.

EVALUATION OF PARAVASCULAR INNER RETINAL DEFECTS USING EN FACE OPTICAL COHERENCE TOMOGRAPHY

PURPOSE

To evaluate the prevalence and risk factors for development of paravascular inner retinal defects (PIRDs) using en face optical coherence tomography.

METHODS

This is a retrospective cross-sectional study. En face and cross-sectional optical coherence tomography images were reviewed (9 × 9 mm or 12 × 12 mm). Paravascular inner retinal defects were classified as either Grade 1 (i.e., paravascular inner retinal cysts) when the lesion was confined within the nerve fiber layer without any communication to the vitreous cavity or Grade 2 (i.e., paravascular lamellar hole) when the defects communicated to the vitreous. Paravascular inner retinal defect grading was correlated with presence of high myopia, stage of posterior vitreous detachment, and presence of epiretinal membrane and retinoschisis.

RESULTS

Of 1,074 patients (2,148 eyes), PIRDs were detected in 261 eyes with a prevalence of 261 per 2,148 eyes (12.2%) and 176 per 1,074 patients (16.4%). A total of 116 eyes (44.4%) displayed Grade 2 PIRDs while 145 eyes (55.6%) were Grade 1. In the multivariate logistic regression model, the presence of partial/complete posterior vitreous detachment, retinoschisis, and epiretinal membrane was significantly correlated with PIRDs (OR = 2.78 [1.7-4.4], P < 0.001; OR = 2.93 [1.7-5], P < 0.001; and OR = 25.9 [2.8-242.5], P < 0.001, respectively). The presence of partial/complete posterior vitreous detachment and epiretinal membrane was also significantly associated with Grade 2 PIRDs versus Grade 1 PIRDs ( P = 0.03 and P < 0.001).

CONCLUSION

Our results indicate that wide-field en face optical coherence tomography facilitates the identification of PIRDs over a large area of retina with a single capture. The presence of PIRDs was significantly associated with posterior vitreous detachment, epiretinal membrane, and retinoschisis, confirming the role of vitreoretinal traction in the pathogenesis of PIRDs.

Large Internal Limiting Membrane Tears: Prevalence, Clinical Characteristics, and Surgical Utility

PURPOSE

To describe the prevalence, clinical and imaging characteristics, and surgical utility of large internal limiting membrane (ILM) tears in eyes with epiretinal membrane (ERM).

DESIGN

Retrospective interventional case series.

METHODS

This was a single-institution study including 71 eyes of 70 consecutive patients that underwent ERM peeling by a single vitreoretinal surgeon between 2016 and 2019. Demographic and clinical data were collected from the medical record. ERMs and large ILM tears were identified and analyzed on multimodal imaging. The main outcome measures were the prevalence and characteristics of large ILM tears in eyes undergoing ERM peeling.

RESULTS

Large ILM tears were present in 23 of 71 eyes (32.4%) with ERM that underwent surgical management. A review of patients with ERM during the same period who did not undergo surgical management found large ILM tears in 8 of 100 eyes (8.0%). Large ILM tears were commonly associated with other signs of ERM-induced retinal traction, including retinal nerve fiber layer schisis in 20 of 23 eyes (87.0%), inner retinal dimpling in 8 of 23 eyes (34.8%), and discrete paravascular red lesions in 16 of 19 eyes (84.2%). In all eyes stained with brilliant blue G, the preoperative diagnosis of large ILM tear was confirmed and the scrolled ILM edge was used successfully to initiate ILM peeling.

CONCLUSIONS

Large ILM tears are often present in eyes undergoing surgery for ERM and are likely caused by ERM contracture. Careful preoperative identification of these tears is helpful for surgical planning because the scrolled flap of ILM provides a convenient and safe "handle" for initiating membrane peeling.

Swept-Source OCT En Face Imaging of Paravascular Inner Retinal Defects

Widefield swept-source optical coherence tomography angiography (SS-OCTA) was performed on eyes with paravascular inner retinal defects (PIRDs) and the morphological alterations of PIRDs were described. Patients with PIRDs were imaged using 12 mm × 12 mm SS-OCTA scans. En face structural and angiographic images of the superficial retinal layers were reviewed along with retinal thickness maps. SS-OCTA en face structural images identified dark, scalloped regions along major retinal veins that corresponded to PIRDs on B-scans. The authors concluded that imaging with both structural and angiographic en face OCT was useful for the diagnosis and monitoring of patients with PIRDs. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:407-411.].

FOVEAL AVASCULAR ZONE AREA ANALYSIS USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY BEFORE AND AFTER IDIOPATHIC EPIRETINAL MEMBRANE SURGERY

PURPOSE

To determine the size of the foveal avascular zone (FAZ) by optical coherence tomography angiography before and after idiopathic epiretinal membrane surgery.

METHODS

Thirteen consecutive patients (13 eyes) with unilateral epiretinal membrane were studied retrospectively. Optical coherence tomography angiography was used to measure the FAZ area within 3 mm × 3 mm scans of the superficial (superficial FAZ) and deep plexus layers (deep FAZ) before and 6 months after vitrectomy. The unaffected fellow eyes were used as controls.

RESULTS

The mean superficial and deep FAZ areas at 6 months after vitrectomy (0.080 ± 0.038 and 0.113 ± 0.045 mm, respectively) were significantly (P < 0.0001, P = 0.0035) larger than the corresponding mean preoperative FAZ areas (0.056 ± 0.030 and 0.082 ± 0.035 mm). However, the areas of FAZ expansion were small (0.024 ± 0.013 and 0.031 ± 0.031 mm). The mean postoperative superficial and deep FAZ areas were significantly (P < 0.0001, P < 0.0001) smaller than those of fellow eyes (0.295 ± 0.108 and 0.410 ± 0.142 mm). Multiple regression analysis showed that preoperative FAZ area had the highest correlation with postoperative FAZ area (P < 0.05).

CONCLUSION

This study showed horizontal contraction of the FAZ area in eyes with epiretinal membrane. Because preoperative FAZ area correlates with postoperative FAZ area, FAZ area may be a useful parameter for determining timing of surgery for epiretinal membrane.

Assessment of the Vitreomacular Interface Using High-Resolution OCT in a Population-Based Cohort Study of Older Adults

PURPOSE

To describe the prevalence of vitreomacular interface (VMI) features and their associated risk factors in the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA) Study.

DESIGN

Cross-sectional population-based study.

PARTICIPANTS

Noninstitutionalized Northern Irish adults 40 years of age or older.

METHODS

Using geographic stratification, a representative sample of people in Northern Ireland was invited to participate in the NICOLA Study. SD OCT images of participants were graded for vitreomacular traction (VMT), macular hole (MH), and epiretinal membrane (ERM) according to the International Vitreomacular Traction Study Group. A subsample was graded in more detail to estimate the prevalence of VMA and VMA area detailing size and location of VMA. Descriptive analysis and risk factors for each VMI feature were determined using generalized estimating equations. Results were standardized to the Northern Ireland population census (2011).

MAIN OUTCOME MEASURES

Cohort profile, standardized prevalence, and risk factor associations of each VMI feature.

RESULTS

Three thousand three hundred fifty-one NICOLA participants had gradable SD OCT images available for at least 1 eye. The prevalence of VMT was 0.5% (CI, 0.31%-0.70%), that for MH was 0.3% (CI, 0.23%-0.52%), and that for ERM was 7.6% (CI, 7.0%-8.3%). A detailed VMA analysis was performed on a subsample consisting of the first 1481 participants. The prevalence of VMA was 22.6% (CI, 21.1-24.2), and VMA area ranged from 0.25 to 42.7 mm² (mean, 12.53 mm²; standard deviation, 6.90 mm²). In multivariate analyses, increased age was associated with an increased odds ratio (OR) of VMT, MH, and ERM. VMA area was positively associated with younger age and normal blood pressure. ERM and MH were present more often in more myopic eyes, associated with an increase in levels of high-density lipoprotein (HDL) cholesterol and triglycerides.

CONCLUSIONS

The epidemiologic characteristics of VMI features indicated that VMI interactions throughout life are age dependent. Vitreous separation reduced to a greater extent in the horizontal meridians compared with the vertical, differing from previous studies. Future longitudinal studies of the evolution of these VMI changes over time would be of great interest.

Anatomical and functional changes in paravascular abnormalities after epiretinal membrane removal

PURPOSE

To investigate the anatomical and functional changes in areas containing paravascular abnormalities (PVA) in eyes with epiretinal membrane (ERM) after surgery.

METHODS

Twenty-eight eyes with concurrent idiopathic ERM and PVA were enrolled in this prospective study. Best-corrected visual acuity (BCVA), central macular thickness (CMT), and areas of PVA in the superficial and deep capillary levels detected on en face optical coherence tomography were measured preoperatively and 1, 3, and 6 months postoperatively. Retinal sensitivity in selected PVA lesions was evaluated by microperimetry preoperatively and 1 and 6 months postoperatively.

RESULTS

The areas of PVA at the superficial capillary level before and 1, 3, and 6 months after surgery measured 1.65 ± 1.27, 0.44 ± 0.62, 0.40 ± 0.64, and 0.38 ± 0.62 mm², respectively, while those at the deep capillary level measured 0.27 ± 0.57, 0.10 ± 0.26, 0.09 ± 0.29, and 0.05 ± 0.15 mm², respectively. The areas of PVA in the superficial and deep capillary levels were significantly smaller postoperatively (all p < 0.001 at the superficial capillary level and p = 0.010 at the deep capillary level). Average retinal sensitivity values in the PVA lesions before and 1 and 6 months after surgery were 11.2 ± 3.5, 12.9 ± 3.2, and 13.2 ± 2.7 dB, respectively; the values at postoperative months 1 and 6 were significantly improved (p = 0.045 and p < 0.001, respectively). BCVA and CMT were significantly improved postoperatively.

CONCLUSION

PVA not only improves anatomically but also functionally after ERM surgery. Vitrectomy can improve not only central vision but also retinal sensitivity in areas of PVA.

An Examination of the Frequency of Paravascular Defects and Epiretinal Membranes in Eyes With Early Glaucoma Using En-face Slab OCT Images

PURPOSE

To examine the frequency of paravascular defects (PDs) and macular epiretinal membranes (ERMs) in eyes categorized as having mild glaucoma or glaucoma suspect using en-face slab analysis of optical coherence tomography (OCT) scans.

MATERIALS AND METHODS

Fifty-seven glaucomatous eyes, 44 low-risk suspect eyes, and 101 healthy control eyes were included in the study. The 101 glaucomatous and suspect eyes had a mean deviation better than -6 dB on the 24-2 visual field, and a spherical refractive error between±6 D or axial length <26.5 mm. Two OCT-graders masked to eye classification identified ERMs and PDs on en-face slab images of the macula and peripapillary retina using horizontal B-scans and derived vertical B-scans.

RESULTS

Glaucomatous eyes had a significantly higher number of PDs and ERMs than healthy controls (PD, P<0.001; ERM, P=0.046) and low-risk glaucoma suspects (PD, P=0.004; ERM, P=0.043). PDs and/or ERMs were present in 16 of 57 (28.1%) glaucomatous eyes, 2 of 44 (4.5%) suspect eyes, and 3 of 101 (3.0%) control eyes. Further, PDs were present in 11 of the 57 (19.3%) glaucomatous eyes, 1 of the 44 (2.3%) suspect eyes and 0 of the 101 (0%) control eyes, ERMs were seen in 7 of the 57 (12.3%) glaucomatous eyes, 1 of the 44 (2.3%) suspects, and 3 of the 101 (3.0%) control eyes.

CONCLUSIONS

Eyes with early glaucoma have a higher frequency of PDs and ERMs than suspects or controls and exhibit PDs even in the absence of ERMs or high myopia.

Retinal detachment due to paravascular abnormalities-associated breaks in highly myopic eyes

PURPOSE

To describe the characteristics of a novel type of retinal detachment (RD) due to paravascular abnormalities (PVAs) associated breaks in highly myopic eyes.

METHODS

We retrospective recruited eight eyes with RD due to PVA-associated breaks. The clinical features and surgical results were evaluated.

RESULTS

All eyes were highly myopic with a mean axial length of 31.31 ± 2.86 mm (27.51-36.52 mm). Two of the eight eyes had multiple paravascular retinal breaks associated with PVAs, four had a single paravascular break with PVAs nearby, and two had multiple paravascular breaks along the same vessels. All breaks were round or oval-shaped, and only three eyes (37.5%) had their breaks located over patchy chorioretinal atrophy. Two of the eight eyes had the breaks outside the arcades, five had their breaks within the arcades, and one had a break within the arcade as well as breaks outside the arcade. Vitrectomy and epiretinal and internal limiting membrane peeling were performed in all cases, with inverted or free internal limiting membrane flap insertions for the perifoveal breaks and endolaser for the more peripheral breaks. All eyes had retinal reattachment after one single operation.

CONCLUSION

RD due to PVA-associated breaks represented a distinct entity. PVAs and the associated breaks should be searched in RD without macular hole or obvious breaks in highly myopic eyes. It may be treated as RD caused by peripheral breaks or as macular hole associated RD depending on the location of the breaks.

Long-term follow-up of retinal nerve fiber layer cleavages in glaucoma patients and suspects

PURPOSE

To investigate the structural and functional characteristics and change of the retinal nerve fiber layer cleavages (RNFLCs) in glaucoma patients and suspects in long-term follow-up.

METHODS

This is a retrospective longitudinal study. Within 43 eyes of 30 subjects, 62 RNFLC locations were detected on color fundus photography. Basic ophthalmic examinations, color fundus photography, optical coherence tomography (OCT), and visual field (VF) test were performed in 6-month intervals. Clinical characteristics and the structural and functional changes of the cleaved areas were analyzed.

RESULTS

RNFLC and localized vitreoretinal traction occurred most commonly along the superotemporal retinal vessel arcade. Nine locations had corresponding defects on OCT deviation map, while 31 locations were associated with defects on OCT deviation map. Three locations had corresponding VF defects. More of the non-highly myopic eyes had lamellar hole than the highly myopes (p = 0.038). The RNFLC lesions in glaucomatous eyes were more frequently associated with OCT defects on deviation map (p = 0.021). There was no difference in the presence of lamellar hole or the number of RNFLCs between the glaucomatous and non-glaucomatous eyes. During a 66.8 ± 37.8-month follow-up, there was no structural or functional progression of the RNFLCs as determined by color fundus photography, VF test, and GPA of OCT interpreted by three ophthalmologists. There was no statistically significant change of RNFLC area (p = 0.268).

CONCLUSIONS

RNFLC did not show detectable functional or structural change in early glaucoma patients and suspects after long-term follow-up.

Paravascular inner retinal abnormalities in healthy eyes

PURPOSE

To investigate the prevalence and characteristics of paravascular inner retinal abnormalities in healthy eyes.

MATERIALS AND METHODS

In this prospective observational case series, we included 178 healthy eyes (178 patients) with no ocular diseases. Eyes with co-existing ocular diseases, e.g., epiretinal membrane, glaucoma, or high myopia, were excluded from the current study. The posterior pole and paravascular areas of the temporal arcade vessels were comprehensively examined by dense radial scanning of optical coherence tomography (OCT) with the extended field imaging technique.

RESULTS

On fundus photography, no inner retinal abnormalities were detected along the temporal arcade vessels. On OCT sections, paravascular inner retinal abnormalities were seen in 77 (43.3%) eyes. In 71 (39.9%) eyes, inner retinal cystoid or fissure-like spaces that had no connection to the vitreous cavity were seen adjacent to the temporal arcade vessels. Most of these lesions were detected only on several consecutive OCT sections. In four (2.2%) eyes, inner retinal cleavages with openings to the vitreous cavity were seen adjacent to the temporal arcade vessels. These lesions were more frequently detected in the inferior hemisphere and along the major retinal veins. No eyes showed typical broad defects of the inner retinal tissue. There were no significant differences in age, gender, visual acuity, refractive error, or axial length between eyes with or without paravascular inner retinal abnormalities.

CONCLUSIONS

Paravascular cystoid or fissure-like spaces were frequently seen in the inner retina of healthy eyes. However, we detected no typical paravascular inner retinal defects in healthy eyes.