Knowledge of VMT natural history leads to better understanding of evolution

Take-home message: More information is needed to understand the natural history of vitreomacular adhesion/vitreomacular traction and risk of progression to clinically significant vitreomacular traction.

By Cheryl Guttman Krader; Reviewed by

Paris-Detecting very minor signs of vitreomacular traction (VMT) is now possible, thanks to the advent of spectral-domain optical coherence tomography (SD-OCT).

However, the risk of progression of these early lesions to clinically significant VMT is not well known, said Alain Gaudric, MD, professor and chairman, Department of Ophthalmology, Lariboisière Hospital, University of Paris Diderot, Paris.

Noting that asymptomatic vitreomacular adhesion (VMA)-the predecessor to VMT-is a common finding, Dr. Gaudric said probably only a minority of eyes with VMA go on to develop mild VMT.

Mild VMT can spontaneously release, go on to persistent VMT with an epiretinal membrane (ERM) that seals the vitreous to the retinal surface, or evolve into a macular hole.

However, further studies with long-term, follow-up are needed to understand the natural history of VMA/VMT in terms of what proportion of eyes follow these different pathways of evolution.

Considering the variable history, the indication for treatment of VMT should not be based on only a single OCT, according to Dr. Gaudric.

“Rather, it should consider the evolution of the traction, worsening of foveal anomalies, and the presence of worsening of visual symptoms,” he explained.

Tracing the possible pathways

VMA-a perifoveal vitreous detachment (PVD) defined by anatomic features detected with OCT-was first described by Uchino et al. in 2001. In that paper, it was reported that in individuals younger than age 50, 60% of eyes will have some partial PVD.

“Today, with SD-OCT, it is very easy to see that the posterior vitreous cortex stays partially detached from the fovea for long periods without causing anatomic or visual disturbance and far before the occurrence of a complete vitreous detachment or complications due to PVD,” he said.

“With time, the vitreous can spontaneously separate entirely from the inner retina, and usually without incident,” Dr. Gaudric said. “So, VMA is not considered a pathologic state.”

As an aside, Dr. Gaudric noted the International Vitreomacular Traction Study (IVTS) Group classification of VMA, traction, and macular hole distinguishes between broad and focal VMA based on size of the adhesion. However, he questioned whether that subclassification has any significance and noted the IVTS Group itself stated it remains unclear whether there is any prognostic difference between focal and broad VMA.

VMT is defined by distortion of the foveal surface, intraretinal structural changes, and/or elevation of the fovea above the retinal pigment epithelium in the absence of full-thickness interruption of all retinal layers.

Early VMT is also asymptomatic, and the only reliable information about its prognosis seems to relate to the specific situation of patients whose fellow eye has a full-thickness macular hole, Dr. Gaudric said.

In 2011, a study by Takahashi et al., which included 43 patients and used SD-OCT, found that 29% of eyes with asymptomatic VMA/VMT went on to develop a macular hole during 18 months’ follow-up.

Dr. Gaudric reported that his group recently analyzed a series of 48 patients with unilateral macular hole and a fellow eye with microstructural foveal changes and found almost the identical result-31% of eyes evolved to a macular hole during a mean follow-up of 18 months.

“However, outside of the context of fellow eyes with macular hole, we have less reliable data,” Dr. Gaudric said. “Although there have been several recent publications dealing with this subject, they used variable definitions of VMA and VMT, were small series, and had short follow-up of less than 2 years.”

After stating those caveats, he summarized the results of the available studies as showing that VMT spontaneous release occurred at a rate of 35% to 51% and with a very low rate of complications.

Dr. Gaudric also observed that those studies had other important limitations as none of them differentiated the cases according to the initial severity of the VMT, and few considered the presence of ERM as a prognostic factor.

“The presence of an associated ERM seems more important for the prognosis of VMT than the size of the adherence,” he said. “The presence of an ERM decreases the chance of spontaneous VMT resolution, but when there is no ERM at the surface of the fovea, there is still room for spontaneous release.”

Alain Gaudric, MD

E: agaudric@gmail.com

This article was adapted from Dr. Gaudric’s presentation at the 2014 meeting of the American Academy of Ophthalmology. Dr. Gaudric is a consultant to Chiltern, a speaker for Bayer Healthcare Pharmaceuticals and Novartis, and receives lecture fees from Carl Zeiss Meditec and Senju.