Posterior Segment Age-related Macular Degeneration
Vitreomacular Adhesion in Exudative Age-related Macular Degeneration Omar S Punjab1
and Peter K Kaiser2
1. Vitreoretinal Fellow, Department of Ophthalmology, Cole Eye Institute, Cleveland Clinic; 2. Professor of Ophthalmology, Cleveland Clinic Lerner College of Medicine
Abstract
There have been several recent studies that support the idea that posterior vitreomacular adhesion (VMA) might be associated with the development and progression of exudative age-related macular degeneration (AMD). Although VMA itself does not cause exudative AMD, retina specialists should consider the presence or absence of VMA when evaluating and treating patients with exudative AMD. This article reviews the recent literature regarding the posterior hyaloid and its relationship to exudative AMD.
Keywords
Vitreomacular traction, vitreous, posterior vitreous detachment, posterior hyaloid, age-related macular degeneration, choroidal neovascularisation
Disclosure: The authors have no conflicts of interest to declare. Received: 10 August 2011 Accepted: 10 September 2011 Citation: European Ophthalmic Review, 2012;6(1):48–50 Correspondence: Peter K Kaiser, 9500 Euclid Avenue, Desk i3, Cleveland, OH 44195, US. E:
pkkaiser@aol.com
Age-related macular degeneration (AMD) is the leading cause of severe visual acuity (VA) loss in industrialised countries and its prevalence is increasing with the aging population.1,2
There are two
forms of the disease – dry AMD and exudative AMD. Dry AMD is associated with drusen early on, followed by atrophy of the macula during the later stages. Exudative AMD is associated with the development of a choroidal neovascular membrane (CNV), which causes fluid exudation or hemorrhage in the macula. Although the pathogenesis of the disease is still under investigation, genetic predisposition, age, ischaemia, and environmental factors all have a role in its development.3,4
The vitreous is a clear gel that is attached anteriorly at the vitreous base and posteriorly to the optic nerve, macula and blood vessels. With time, vitreous degeneration occurs, which subsequently leads to contraction and separation from the macula and optic nerve (known as posterior vitreous detachment or PVD). Vitreomacular adhesion (VMA) has been related to several macular diseases, including vitreomacular traction syndrome, diabetic macular oedema, macular hole and epiretinal membrane. The concept of the pathogenesis of macular degeneration based solely on a retinal pigment epithelium (RPE) disease has left many questions unanswered and, hence, the role of the vitreous and its adherence to the retina in exudative AMD has recently been studied. This review provides a critical discussion of current scientific evidence of the role of the vitreous in the pathogenesis of exudative AMD.
Posterior Vitreous Adhesion and its Relationship with Exudative Age-related Macular Degeneration
Traditionally, the vitreous has not been associated with exudative AMD. However, recent studies have shown that the posterior hyaloid might have a role in the pathogenesis and progression of the exudative form of AMD.
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A high incidence of posterior vitreous attachment was recently observed intra-operatively in patients with exudative AMD.5
Schmidt et
Studies using ultrasound suggest that complete PVD occurs less frequently in eyes with AMD compared with age-matched controls, and that a higher incidence of VMA is detected in both exudative and non-exudative AMD.7,8
Other studies have shown that an attached
posterior vitreous cortex, partial peripheral PVD, and central adhesions surrounded by shallow detachment of the posterior vitreous cortex were significantly more frequent in exudative AMD than in non-exudative AMD and control eyes.9,10
VMAs were described in one study in 36 % of eyes with exudative AMD, significantly more frequently than in eyes with non-exudative AMD or control eyes.9
who found VMA in 38 % of eyes with exudative AMD,10
These results were confirmed by Robison, and by Lee,11
who found VMA in 22.3 % of eyes associated with neovascular AMD.
Optical coherence tomography (OCT) is a non-invasive method that provides micron-resolution, cross-sectional imaging that is useful in imaging the retina and vitreoretinal interface. Conventional time-domain OCT has been used to evaluate the vitreous in AMD, and such studies have suggested that there is a higher rate of VMA in exudative AMD, whereas no difference was found between non- exudative AMD and normal populations.9
Similarly, using spectral
domain OCT combined with simultaneous scanning laser ophthalmoscope (spectral OCT/SLO), Mojana et al.12
demonstrated
posterior hyaloidal adhesion in 170 eyes with AMD, which frequently caused VMT in eyes with CNV. In their study, exudative AMD had a significantly higher incidence of incomplete PVD compared with age-matched control eyes, and a similar trend existed when
© TOUCH BRIEFINGS 2012
al. also observed that intra-operative findings during vitrectomy showed little liquefaction of the vitreous gel, an incomplete PVD, and remarkably firm attachments at the macula in all patients with AMD in their series (10/10).6
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