Fig. 1
Clinical findings in Irvine-Gass syndrome. (a) Cystoid macular edema due to leakage of fluorescein at the macula; note the petaloid patterns of leakage. (b) Optical coherence tomography (OCT) showing the cystic changes due to release of inflammatory mediators
In 1970, Reese et al. described an unusual macular condition in which an incomplete posterior vitreous detachment (PVD) resulted in traction on the macula accompanied by decreased visual acuity (VA) [5]. This condition was confirmed, not by imaging techniques (such as OCT) as they were not yet available at that time, but through the use of histological studies. Therefore, the term vitreomacular traction (VMT) syndrome was coined.
Epidemiology
In observational and interventional studies, the mean age of patients diagnosed with VMT is around 65–75 years, with a predominance of females. The condition is unilateral in approximately 80 % of cases [6].
The prevalence of epiretinal membrane (ERM) increases with age and is approximately 2 % in people over 50 years of age and 20 % in individuals older than 70 years. It can be bilateral in 20–30 % of cases [7, 8].
Idiopathic VMT syndrome can occur in either sex, at any age, and has no racial predilection [8]. The incidence in women seems to be distinctly higher (about 65 %), which may be attributed to the earlier onset of PVD due to premature vitreous liquefaction, likely associated with declining estrogen levels in the postmenopausal period [9].
CME and VMT: Physiopathogenesis
A common physiopathological event in these diseases is vitreous syneresis (Fig. 2a). Increasingly with age, synchysis of the vitreous gel and ultimately syneresis lead to posterior vitreous detachment (PVD), a non-pathological process. PVD is not related to significant problems in most patients; however, if there is an imbalance of vitreal glycosaminoglycans and hyaluronic acid, the vitreoretinal adhesion to the macular area does not weaken; pathological adhesion of the vitreous to the macular area may occur, and abnormal PVD may happen, in a process known as vitreomacular adhesion (VMA) (Fig. 2b) [1, 9, 10], that results in no abnormalities at the macular architecture.
Fig. 2
Physiopathogenesis of vitreomacular traction (VMT) syndrome. (a) Natural history of posterior vitreous detachment and vitreous syneresis. (b) Proposed mechanism of epiretinal membrane (ERM) proliferation in vitreomacular traction syndrome, according to Johnson [4] and Chang et al. [14]. (1) After development of a partial posterior vitreous detachment, small splits within the internal limiting membrane may form, allowing glial cells to gain access to the superficial retina (arrows), which serves as a scaffold for ERM proliferation. (2) These cells also proliferate on the detached hyaloid face (arrow), strongly anchoring the vitreous to the macula
Focal VMA occurs when the perifoveal vitreous cortex is adherent to the macula after detaching from the surrounding retina. This situation typically is asymptomatic non-pathological and causes no discernible retinal changes [2]. Alternatively, VMA may result in abnormalities of the macular anatomy, resulting in the so-called vitreomacular traction (VMT) syndrome (Fig. 2b); this occurs when the forces of macular attachment are strong enough to cause anatomical disturbance of the macular architecture (Fig. 2b).
In VMT, tractional forces on the macula may cause two different pathologies [11] (Fig. 3):
Fig. 3
Distinct HD-OCT images of VMT syndrome based on the morphology and extension of the vitreomacular adhesion. (a) V-shaped VMT (focal, less than 1500 um) and cystoid macular edema by 3-dimensional SD-OCT. (b) J-shaped VMT (broad, more than 1500 um) and epiretinal membrane by 3-dimensional SD-OCT. (c) V-shaped VMT (focal, less than 1500 um) and cystoid macular edema by 3-dimensional SD-OCT. (d) J-shaped VMT (broad, more than 1500 um) and epiretinal membrane by 3-dimensional SD-OCT. (e) Focal VMT measurement based on the extension of traction. The greatest linear adhesion point 698 μm at the macular area, which better reflects the surgical prognosis in comparison with the morphological classification by preliminary data from 36 eyes that underwent surgery. (f) Diffuse VMT measurement based on the extension of traction. The greatest linear adhesion point 1,728 μm at the macular area, which better reflects the surgical prognosis in comparison with the morphological classification by preliminary data from 36 eyes that underwent surgery
- 1.
A focal configuration of the traction, also named V-shaped macular traction (Fig. 3), which corresponds to less than 1,500 μm of traction: this is related to macular holes (Fig. 4) and cystoid macular edema (Fig. 5).
Fig. 4
Evolution of macular hole formation in focal (less than 1500 um) VMT syndrome. HD-OCT images of patients in distinct phases of VMT. (a) In some susceptible eyes, there is an abnormal and strong vitreomacular adhesion causing a persistent foveal traction. (b) Vitreomacular adhesion changing the foveal anatomy causing the vitreomacular traction (VMT) syndrome. (c) VMT and the associated cystoid macular edema. It is still unclear why do some eyes progress to full-thickness macular holes and why do eyes detach the posterior hyaloid and the traction component present regression. (d) If the macular traction persists, the cystoid macular edema may progress to a pseudocystic change, and the stage IB macular hole may develop. (e) Traction leading to a stage 2 macular hole with eccentric pseudo-operculum and perifoveal detachment which is universally associated with macular holes. (f) Traction leading to a more advanced stage 2 macular hole with eccentric pseudo-operculum, cystic changes at the edges of the holes, and a more advanced and perifoveal detachment. (g) Progression of traction resulting in a stage 3 macular hole. (h) Progression of traction resulting in a stage 4 macular hole
Fig. 5
Fundus photograph. (a) Red-free image, (b) fundus autofluorescence, (c) and fluorescein angiogram (d) of a patient with tractional cystoid macular edema. The fundus photograph (a) shows a yellow spot that corresponds to the hyperautofluorescent pattern on the autofluorescence image. A corresponding midphase fluorescein angiogram (d) shows minimal leakage from the retinal capillaries which are completely different than. High-definition optical coherence tomography (e, f) shows focal vitreomacular adhesion with a perifoveal vitreous detachment causing tractional cystoid foveal edema. Note that the focal pattern of foveal leakage and no angiographic disk edema related to tractional component (d) is completely different than petaloid pattern of edema associated to angiographic edema mediated by cytokines (Fig. 1a); the OCT findings related to the tractional component (e–f) are also mild in comparison to the edema mediated by cytokines (Fig. 1b)
- 2.
A broad configuration of the traction, also named J-shaped macular traction, which corresponds to more than 1,500 μm of traction: this is related to epiretinal membrane formation and retinal thickening (Fig. 3).
By definition, VMT is always pathologic and symptomatic [1]. Symptoms commonly associated with VMT include metamorphopsia and blurred vision. Asymptomatic VMA is not an indication for treatment and is a normal transient phase in the course of PVD.
Diagnosis
The first step in diagnosis is a complete history from the patient, including type and duration of symptoms, past ocular history (i.e., glaucoma, previous ocular surgeries, trauma, etc.), and past systemic history (i.e., systemic diseases and medications), including the use of drugs potentially related to the development and increase of macular edema (e.g., systemic niacin, topical prostaglandin analogs) [6]. The cardinal symptoms of macular diseases including VMT and ERM are related to anatomical macular changes and include decrease in visual acuity (VA), metamorphopsia, micropsia, and rarely photopsia [6].
Because focal VMT may cause minimal symptoms, it is often diagnosed during OCT evaluation performed in patients for other causes. Chronicity and strong tractional forces in VMT can further distort the retina causing intraretinal cysts or posterior pole tractional retinal detachment. If intraretinal cysts cause a dehiscence in the internal limiting membrane (ILM), a lamellar hole is created, and if a complete break from the ILM to the retinal pigment epithelium (RPE) is formed, a full-thickness macular hole occurs (Fig. 4), seen as in interruption of retinal anatomy with surrounding edema in the macular area [11–13].
Visualization of the fundus should include the peripheral retina to exclude pathology such as retinal tears, vascular lesions, chorioretinitis, and intraocular tumors that could induce macular edema [11].
OCT is useful in assessing the location of cleavage planes for patients in eyes with surgical indication, helps in predicting visual prognosis, and also in postoperative follow-up, assisting, for example, in the detection of recurrent and residual ERMs [14–16]. Analysis of prognostic factors for vision recovery is possible by assessing the structural integrity of the ellipsoid zone (IS/OS junction) and of the external limiting membrane (ELM) [6].
The diagnosis of VMT syndrome is often difficult to make through clinical examination alone. Even with thorough fundus contact lens examination, the firm translucent adhesions of the vitreous at the macula may be essentially imperceptible. This explains why this condition was considered to be rare and underdiagnosed [11, 13, 16]. Distinct clinical presentations of VMT have been described [11, 17, 18]. They include macular surface wrinkling, similar in appearance to ERM. Although in the past this syndrome was considered infrequent and not correlated with other maculopathies, it is now known that ERM may be associated in most cases. A thickened and taut posterior hyaloid membrane may also be noted [19]. Tractional CME is a subtle variant of VMT syndrome, and it may be present in cases of unifocal vitreofoveal traction arising from partial PVD [11].
Classification of CME Related to VMT
The focus of this chapter is to describe the surgical management of CME. For didactic reasons, we will divide CME that may benefit from surgical indications into two different clinical patterns according to the distinct physiopathogenesis, fluorescein angiogram (FA) and OCT findings [11, 13, 16, 20]:
- 1.
CME after cataract surgery related to persistent vitreous base traction and secondary VMT: in these eyes, the common finding is the angiographic papillary edema (extensive FA leakage) associated with a petaloid pattern of leakage at the macula and an important extension of CME by OCT due to chronic release of high amounts of inflammatory mediators which results in a secondary tractional component such as posterior hyaloid traction and/or epiretinal membrane (ERM) formation (Fig. 1) [11, 13, 16, 20].
- 2.
CME related to primary VMT (Figs. 2, 3, 4, and 5): in these eyes, the primary abnormality is an abnormal and incomplete posterior vitreous detachment (PVD) (Fig. 3). The common finding is minimal or no angiographic papillary edema (minimal FA leakage at the optic disk and macula) as well as a focal extension of CME seen on OCT due to a primary tractional component (Figs. 3, 4, and 5) and minimal release of inflammatory mediators. This results in minimal macular changes on fundus photographs, FA and OCT (Fig. 5). ERM may be also present (Fig. 6) [11, 13, 16, 20].
Fig. 6
Epiretinal membrane (ERM) and internal limiting membrane (ILM) analyzed by electron microscopy showing a segment of the ILM (arrow) and epiretinal membrane (arrowhead). The matrix around the surface is composed of moderate amount of collagen fibrils with native collagen (panel featured above right) (TEM 3800; picture top right TEM 24000). The complex interaction of ERM and ILM is the rationale to stain and remove the ILM in all cases related to ERM formation in order to minimize the possibility of ERM recurrence and/or macular edema
CME and Secondary Vitreoretinal Interface Disorders (VMT)
CME associated to secondary vitreoretinal interface disorders (VMT) is frequently related to ERM formation in pseudophakic eyes. Surgical intervention is indicated if best-corrected visual acuity (BCVA) is worse than 20/40 and/or metamorphopsia in eyes previously undergoing medical treatment as described before (topical and intravitreal steroids/anti-VEFG) [11, 13, 16, 20].
CME Secondary to VMT
The vitreous is attached to all contiguous structures of the inner eye, including the internal limiting membrane (ILM) of the retina. The concept of VMT is an abnormal adhesion of the vitreous at the macula which may result in morphological macular abnormalities. There are three basic morphological abnormalities that may be observed in such primary VMT (Fig. 5): (1) CME, (2) macular holes, and (3) epiretinal membrane and retinal swelling [11, 13, 16, 20].
VMT and Associated Maculopathies Epiretinal Membrane (Broad VMT; Extension > 1,500 μm)
The ERM may play an important role in chronic VMT syndrome [14, 20], mainly in broad adhesions (Fig. 3b) [21]. Partial PVD with vitreal traction can cause small splits within the ILM, allowing glial cells to gain access to the superficial retina (Fig. 2b). In these eyes, epiretinal fibroglial membranes proliferate from the retinal surface onto the back surface of the detached posterior vitreous face. This configuration imparts an increased strength of the vitreomacular adhesion and prolongs the duration of the VMT by preventing the spontaneous separation of the vitreous and the macula (Fig. 2b) [11, 13, 16]. Furthermore, the proliferative epiretinal fibroglial membranes contribute contractile forces by increasing the tangential traction via thickening and tightening of the detached posterior hyaloid and anchoring the posterior hyaloid to the surrounding retinal surface, thus enhancing the anteroposterior traction caused by the VMT adhesion [14, 20] (Fig. 6).
Macular Hole and Tractional Cystoid Macular Edema (Narrow VMT; Extension <1,500 μm)
The vitreoretinal relationship in eyes with tractional CME is similar to that seen in eyes with an early-stage idiopathic macular hole (MH) and 4A-C [15, 20–26]. The smaller the area of the foveal attachment, the greater the point force that is exerted, causing more serious disease [24]. This condition of focal adhesion, also known as vitreofoveal traction syndrome, implies an MH (Fig. 4d–f) and CME formation (4A-C) [9, 20–24]. The strong effect of narrow bands of adhesion can lead to this variant of VMT, also referred as tractional CME (Fig. 5).
Tractional CME must be distinguished from inflammatory diseases such as postoperative pseudophakic CME, retinal vascular diseases, or uveitic CME, which generally exhibits important capillary leakage on fluorescein angiography (Fig. 1a). Otherwise, tractional CME not linked with inflammation shows only minimal leakage if at all [15] (Fig. 5a–d). The reason why vitreofoveal traction leads to MH in some cases (Fig. 4d–f) and tractional CME without hole formation in other cases (Fig. 4a–c), even with time, has yet to be determined [11, 13, 15, 16].
Specific Surgical Indications for CME Associated with VMT
In narrow VMT (less than 1,500 μm), surgical intervention by pars plana vitrectomy (PPV) is indicated if BCVA is worse than 20/40 and/or persistent metamorphopsia is present with symptoms for more than 6 months [11, 13, 16] (Fig. 3).
However, it is reported that incipient eyes with narrow configurations of VMT (<1,500 μm), especially in those with CME associated with VMT, may have spontaneous resolution after complete posterior vitreous detachment (PVD). For this reason, it is especially important that surgical indications in these eyes be very well scrutinized (Figs. 3, 4, and 5) [11, 13, 16]. Normally, in such eyes, surgical consideration requires 6 months of consistently poor or decreased BCVA and vision measurement worse than 20/40 associated with complaint of metamorphopsia [11, 13, 16].
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
