can develop. Studies [11] have shown that the membranes inducing pucker in eyes with MH are smaller in diameter and farther from the center of the macula than eyes with MP alone.

14.6.2.1  Lamellar Hole (LH)

LH is characterized by a thin, irregular fovea and avulsion of inner layers of the central macula. SD-OCT/SLO has proven useful in the diagnosis of LHs, which have characteristic configuration on the longitudinal scans (Fig. 14.10). Clinically, patients may retain relatively good visual acuity but in some instances surgery is indicated for distortions and loss of visual acuity.

LH is believed to result from an abortive process of MH formation, although this is by no means certain. Foveal cysts are believed to be the precursors of either full-thickness MH or LH. Indeed, a recent study [17] confirmed the presence of intraretinal cysts in both MH and LH. Interestingly, a higher prevalence of cysts was found in MH (100%) than LH (54.5%) and MP (17.9%). Similar to what was previously described for MP, VPA seems to play a role in the formation of cysts in LH as well. LH with VPA had cysts in 50% of cases, while LH without VPA only had cysts in only 20% of cases.

Based on all the aforementioned findings, it would appear that VPA is important in some, but not all vitreomaculopathies. Indeed, these diseases can be grouped according to the prevalence of VPA (in descending order) as: MH with cysts (87.5%), MP with cysts (80%), LH with cysts (50%), LH without cysts (20%), and MP without cysts (4.3%) (Fig. 14.11) [17]. Regarding intraretinal cysts, there appears to be a similar distribution with 100%

prevalence in MH with VPA, 80% in MP with VPA, 75% in LH with VPA, 42.9% of LH without VPA, and 4.3% of MP without VPA (Fig. 14.12) [35]. Thus, VPA appears to be an important factor in the pathophysiology of vitreomaculopathies, probably by influencing the vector of forces at the vitreo-retinal interface.

14.6.3  Age-Related Macular Degeneration (AMD)

The etiology of AMD is multifactorial. Risk factors include age, family history, ethnicity, cardiovascular diseases, hypertension, and cigarette smoking. AMD can be subdivided into two patterns: (a) atrophic, dry, or nonexudative AMD and (b) neovascular, wet, or exudative AMD. Dry AMD is by far the most common type, characterized by drusen and geographic atrophy. Wet AMD is characterized by neovascularization with edema and sometimes hemorrhage, causing severe vision loss. While it is known that neovascularization arises from the choriocapillaris through breaks in the Bruch’s membrane, the stimuli and true cause(s) for exudative AMD are not known.

Recent studies [36] employing ultrasound and OCT have shown that persistent vitreo-macular adhesion is more prevalent in exudative AMD (Fig. 14.13), whereas a higher prevalence of complete PVD was found in eyes with dry AMD. This suggests that vitreo-macular adhesion may be a risk factor for choroidal neovascularization and exudative changes in AMD, whereas PVD may be protective against exudative AMD. Subsequent studies confirmed these findings [37, 42] and determined that these phenomena are only important during active AMD and not in end stages such as geographic atrophy and disciform macular scarring. Furthermore, these studies showed that genetics

and environmental factors do not appear to influence the role of vitreous in exudative AMD.

14.6.4 Vitreo-Macular Traction Syndrome (VMTS)

VMTS is characterized by anomalous PVD with persistent vitreous adhesion to the macula, resulting in macular thickening, edema, and decreased visual acuity. VMTS is more prevalent in women than in men, and usually occurs in the sixth and seventh decade of life. Spontaneous

resolution may occur following complete PVD, but cell proliferation has been implicated as a possible mechanism that may hinder PVD [38]. VMTS is distinguished from MP in that there are no corrugations in the retina, since the traction is axial and not tangential. At times, this axial traction is so severe that it elevates the central retina (Fig. 14.14). Presenting symptoms are predominantly decreased central vision with less metamorphopsia than in patients with MP. The other distinguishing feature is that VMTS features fullthickness vitreous attachment to the macula, in contrast to MP where vitreoschisis splits the posterior vitreous cortex