Classifications of vitreomacular traction syndrome: diameter vs morphology

BROAD VITREOMACULAR ATTACHMENT-INDUCED MACULAR HOLE: Structural Changes and Surgical Outcome

PURPOSE

This study aims to describe the structural changes and surgical outcomes of full-thickness macular holes (FTMHs) induced by vitreomacular traction with broad vitreomacular attachment (VMA).

METHODS

A retrospective analysis of idiopathic FTMHs from October 2010 to May 2022 was conducted. Patients with FTMHs and no retinal detachment (RD) induced by broad VMA (the study group) were compared with a control group consisting of typical FTMHs with focal VMA.

RESULTS

Thirty-one eyes had broad VMA-associated FTMH, among which seven eyes (22%) were with concurrent RD. Among the total of 24 cases without RD, 8 (33%) exhibited schisis. The incidence of lamellar holes associated epithelial proliferation and multiple membrane traction was significantly higher in the study group. One hundred percent FTMH closure was observed postoperatively in both groups. Although the postoperative visual acuity was not significantly different, the study group showed a greater ellipsoid zone disruption length.

CONCLUSION

Broad VMA-induced FTMHs are characterized by diverse macular structural changes, including schisis and macular detachment. These FTMHs are associated with a higher incidence of lamellar holes associated epithelial proliferation and multiple membrane traction. Surgical outcomes for FTMHs induced by broad VMA are similar to those induced by typical focal VMA, with both groups demonstrating a 100% hole-closure rate.

Mechanistic Insights into the Pathogenesis of Proliferative and Nonproliferative Vitreomacular Traction

PURPOSE

To describe the vitreoretinal interface in vitreomacular traction (VMT) by using novel optical coherence tomography (OCT) methods; wide-angle montage, and pseudomotion OCT imaging systems.

DESIGN

Observational case series.

METHODS

Wide-angle montage OCT images of horizontal and vertical scans through the fovea were acquired in 50 eyes of 46 consecutive patients with VMT. Baseline fundus scans were obtained. These were followed by scans acquired with an eye-tracking system performed immediately after vertical and horizontal eye movements. Three scans were then superimposed to compare changes in the contour and position of the posterior vitreous.

RESULTS

The subjects were classified as VMT with ("proliferative"; 48.0%) and without ("nonproliferative"; 52.0%) thickened posterior vitreous. Epiretinal membrane was observed in 26.9% of nonproliferative and 95.8% of proliferative VMT eyes (P = 3.6 × 10^-7). No eye of proliferative and 57.7% of nonproliferative VMT eyes had wavy contoured posterior vitreous (P = 4.0 × 10^-6). None with proliferative VMT, but 91.7% of nonproliferative VMT eyes, showed motion induced changes of posterior vitreous following eye movement (P = 2.0 × 10^-8). The posterior vitreous detachment extended beyond the scanned area in 34.6% of nonproliferative and 8.3% of proliferative VMT eyes (P = .040).

CONCLUSIONS

By dynamically evaluating the vitreoretinal interface of patients with VMT, the static contraction forces of a thickened posterior vitreous at the macula are implicated in proliferative VMT. This contractile force is not strongly implicated in the majority of VMT eyes with nontaut and more mobile vitreous (nonproliferative VMT). VMT and its associated complications are determined by at least 2 different pathophysiological mechanisms.

OCT proves that vitreomacular adhesion is significantly more likely to develop vision-threatening retinal complications than vitreomacular separation

Background

SD-OCT is becoming commonplace in everyday practice. Vitreomacular adhesions (VMAs) are being more routinely diagnosed. Predictive studies to the natural course of VMA are thus clinically significant. Spectral domain-optical coherence tomography (SD-OCT) was presently utilized to analyze the incidence of floaters, the complete vitreomacular separation or VMA, the VMA complication, the vitreomacular angle (VMAng), and the complication mechanism.

Methods

Monthly SD-OCT was performed on patients with/without symptomatic floaters. OCT allowed VMA and vitreomacular separation to be compared. The incidence was assessed applying one-tailed Fisher’s exact tests. The VMAngs between the inner retina and posterior hyaloid were measured, and the complication mechanism was studied using OCT image. For macular hole (MH), pre- and/or post-operative best corrected visual acuities (BCVAs; LogMAR), refractions and photoreceptor conditions were also evaluated.

Results

Totally, 124 eyes were included; there were 116 eyes with VMA and 8 eyes with vitreomacular separation. Considering the percentages over 124 eyes, floaters were present in 14.5% of enrolled eyes (=18/124), consisting of 12.9% of eyes with VMA (16/124) and 1.6% of eyes with vitreomacular separation (2/124). Moreover, there were twelve eyes (9.7%) with VMA-associated vision-threatening complications, including MH (n = 8; 6.5%), retinal detachment (RD; n = 2; 1.6%), vitreomacular traction (VMT; n = 1; 0.8%) and macular pucker (MP; n = 1; 0.8%). Eyes with initial VMA had a significantly greater possibility of complications than eyes with initial vitreomacular separation (p = 0.03). Among these eyes with MH (n = 8), the pre-operative BCVA (LogMAR) was 1.1 ± 0.5, which was insignificantly (p = 0.35) improved to 0.8 ± 0.7 post-operatively. The VMAng of VMA eyes with MHs was 24.2 ± 24.9° (n = 8). The critical VMAng was 13.3°.

Conclusions

A minority of eyes with VMA or vitreomacular separation had floaters. Moreover, the use of SD-OCT could identify vision-threatening sequelae, namely MH, RD, MP and VMT, and this was significantly more frequent in eyes with VMA than in eyes with complete vitreomacular separation. Therefore, SD-OCT might be a useful way of identifying either identity, and evaluating VMA-associated complications. Whether VMA eyes with MH (n = 8) that have a VMAng greater than critical VMAng have a greater likelihood of tangential traction and subsequent MH needs further investigation.

[Current progress of research and use of microminipigs in drug development]

The use of minipigs has been increasing in the areas of pharmacology researches and drug development. The microminipig developed by Fuji Micra Inc. (Shizuoka, Japan) inherits characteristics of other pig strains showing several similarities to humans in anatomy, physiology, omnivorousness and diurnal, but at the same time has several advantages over other pig strains because of its small size which allows easy keeping, handling and dosing, and saving of test substances. The microminipig weighs about 10 kg at the age of 6 months. Canine cages can be used to keep the animal. Swine leukocyte antigens (SLA) are defined in each individual animal which is useful for testing immunological reactions. As there are many similarities in metabolic enzymes and transporters to those in humans, the microminipig is a powerful animal model for toxicokinetic studies. Unfortunately as in other minipigs the microminipig is not appropriate for embryo-fetal development studies of antibody drugs due to its poor placental transfer, but can be used for other reproductive and developmental studies. Repeat dose toxicity, safety pharmacology, immunotoxicity and local tolerance studies should be also other arenas of this animal model.

The Relationship of Neutrophil to Lymphocyte Ratio with Vitreomacular Traction Syndrome

This study was conducted to reveal the role of systemic low-grade inflammation by calculating the Neutrophil/Lymphocyte Ratio (NLR) in Vitreomacular Traction Syndrome (VMTS) of different etiologies. A retrospective examination was made of the medical records at a tertiary referral hospital. The study included 31 patients with diabetic VMTS, 27 patients with idiopathic VMTS, and 35 healthy subjects as the control group. The White Blood Cell (WBC) counts and Neutrophil-to-Lymphocyte Ratio (NLR) was compared. There were insignificant differences between the groups in terms of mean age and female/male ratio (P>0.05). The mean ± Standard Deviation (SD) of NLR was calculated as 2.43 ± 0.83 in the diabetic VMTS group, 2.38 0.96 in the idiopathic VMTS group, and 1.83 WBC: White blood cell; VMTS: Vitreomacular traction syndrome; SD: standard deviation; µL: microliter; fL: femtolitre; n: number. 0.52 in the control group (P=0.007). The values of the diabetic and idiopathic VMTS groups were significantly higher than those of the control group (P=0.002 and P=0.032, respectively). However, differences between the diabetic and idiopathic VMTS groups were insignificant (P=0.651). This study found significantly higher NLR in patients with diabetic and idiopathic VMTS than the control group. Elevated NLR could therefore be a potential indicator of VMTS, irrespective of the etiology.

Correlation of Vitreomacular Traction with Foveal Thickness, Subfoveal Choroidal Thickness, and Vitreomacular/Foveal Angle

PURPOSE

To investigate the structure of vitreomacular traction (VMT), specifically, if a correlation exists between 1) the VMT type/grade and the central foveal thickness (CFT) and subfoveal and adjacent choroidal thickness, 2) the vitreomacular/foveal angle (VMFA) and the CFT and subfoveal and adjacent choroidal thickness, and 3) the diameter of vitreomacular adhesion (VMA) and CFT and subfoveal and adjacent choroidal thickness.

MATERIALS AND METHODS

Retrospective, multicenter image analysis study. We analyzed raster scans of the macula taken with spectral-domain optical coherence tomography (SD-OCT) of 61 eyes of 55 patients with VMT. Conventional scans of the vitreoretinal interface were analyzed to measure CFT and the degree of VMFA. Enhanced depth imaging (EDI) scans were analyzed to measure the choroidal thickness in the macula. The multivariate test of means and the t-test were used for statistical comparisons.

RESULTS

There was no statistically significant difference in CFT between focal vs broad and concurrent vs isolated type VMT. Central (p = 0.009), nasal (p = 0.004), and temporal (p = 0.007) subfoveal choroidal thickness was significantly higher in broad VMT compared to focal VMT. There was difference in both CFT (p = 0.035) and central (p = 0.005), nasal (p = 0.01), and temporal (p = 0.001) choroidal thickness between moderate and severe VMT. There was a correlation between VMFA and CFT, where a wider angle was associated with increased CFT (p = 0.026). The broader VMA was associated with increased central subfoveal (p = 0.032), nasal (p = 0.05), and temporal (p = 0.01) choroidal thickness.

CONCLUSIONS

Eyes with broad VMT have thicker choroid than eyes with focal VMT, which have a more open vitreomacular angle. The angle of VMT is related to distinct CFTs.

The design and validation of an optical coherence tomography-based classification system for focal vitreomacular traction

PURPOSE

To develop and validate a classification system for focal vitreomacular traction (VMT) with and without macular hole based on spectral domain optical coherence tomography (SD-OCT), intended to aid in decision-making and prognostication.

METHODS

A panel of retinal specialists convened to develop this system. A literature review followed by discussion on a wide range of cases formed the basis for the proposed classification. Key features on OCT were identified and analysed for their utility in clinical practice. A final classification was devised based on two sequential, independent validation exercises to improve interobserver variability.

RESULTS

This classification tool pertains to idiopathic focal VMT assessed by a horizontal line scan using SD-OCT. The system uses width (W), interface features (I), foveal shape (S), retinal pigment epithelial changes (P), elevation of vitreous attachment (E), and inner and outer retinal changes (R) to give the acronym WISPERR. Each category is scored hierarchically. Results from the second independent validation exercise indicated a high level of agreement between graders: intraclass correlation ranged from 0.84 to 0.99 for continuous variables and Fleiss' kappa values ranged from 0.76 to 0.95 for categorical variables.

CONCLUSIONS

We present an OCT-based classification system for focal VMT that allows anatomical detail to be scrutinised and scored qualitatively and quantitatively using a simple, pragmatic algorithm, which may be of value in clinical practice as well as in future research studies.

Variability in Presentation of Bilateral Vitreomacular Traction

PURPOSE

Vitreomacular traction (VMT) is a condition characterized by an incomplete posterior vitreous detachment resulting in traction on the macula and possible subsequent decrease in visual acuity and/or other symptomatology. Vitreomacular traction often presents as a unilateral condition, with some cases developing bilaterality with disease progression. The natural course and presentation of VMT vary widely among individuals. There is no extensive literature regarding the prevalence of VMT in the general population; therefore, little is known on the laterality.

CASE REPORTS

We present eight cases of bilateral VMT encountered in a primary care setting. These cases highlight the variability in presentation, symptomatology, and clinical outcome between and within eyes of patients with bilateral VMT.

CONCLUSIONS

Spectral-domain optical coherence tomography has provided new insight into VMT by allowing better visualization of the vitreoretinal interface. Using spectral-domain optical coherence tomography, eight unique cases of bilateral VMT were confirmed and classified. However, despite the bilaterality noted in each case, the clinical presentation and course of disease varied among patients. Because of the paucity of epidemiological data regarding VMT, the laterality of the condition, risk factors for involvement, and overall prognosis remain unclear.

Retinal Changes Induced by Epiretinal Tangential Forces

Two kinds of forces are active in vitreoretinal traction diseases: tangential and anterior-posterior forces. However, tangential forces are less characterized and classified in literature compared to the anterior-posterior ones. Tangential epiretinal forces are mainly due to anomalous posterior vitreous detachment (PVD), vitreoschisis, vitreopapillary adhesion (VPA), and epiretinal membranes (ERMs). Anomalous PVD plays a key role in the formation of the tangential vectorial forces on the retinal surface as consequence of gel liquefaction (synchysis) without sufficient and fast vitreous dehiscence at the vitreoretinal interface. The anomalous and persistent adherence of the posterior hyaloid to the retina can lead to vitreomacular/vitreopapillary adhesion or to a formation of avascular fibrocellular tissue (ERM) resulting from the proliferation and transdifferentiation of hyalocytes resident in the cortical vitreous remnants after vitreoschisis. The right interpretation of the forces involved in the epiretinal tangential tractions helps in a better definition of diagnosis, progression, prognosis, and surgical outcomes of vitreomacular interfaces.

[Importance of morphological and functional diagnostics of the vitreoretinal interface]

Optical coherence tomography (OCT) is the standard examination for assessment of the vitreoretinal interface (VRI); therefore, it is essential to select the appropriate scan modalities to detect the total amount of morphological changes, not only at the VRI but also in all layers of the retina and in both the foveal and parafoveal areas. For the success of a surgical intervention in the treatment of vitreomacular interface disorders, morphological changes, especially in the outer retinal layers, have been determined to be of prognostic interest in high-resolution OCT. This article gives an overview of current OCT examination procedures as well as correlative aspects of morphological and functional findings.