Clarifying the mechanism of idiopathic macular hole development in fellow eyes using spectral-domain optical coherence tomography

Abstract

Background: To clarify the mechanism of idiopathic macular hole development, we evaluated the vitreoretinal relationship in fellow eyes of those with a macular hole and normal eyes using spectral-domain optical coherence tomography. Thirty-one fellow eyes and 34 normal volunteer eyes without a posterior vitreous detachment (PVD) were included.

Results: WE CLASSIFIED SIX VITREOMACULAR RELATIONSHIPS: type 1, no PVD, five fellow eyes (16.1%) and nine control eyes (26.5%); type 2, shallow PVD with perifoveal vitreous attachment, seven fellow eyes (22.6%) and 19 control eyes (55.9%); type 3, shallow PVD with pinpoint foveal vitreous traction, seven fellow eyes (22.6%) and no control eyes (0%), type 4a; shallow PVD with a round defect in the posterior vitreous cortex over the perifoveal area with vitreous attachment to the perifoveal area, two fellow eyes (6.5%) and one control eye (2.9%); type 4b, shallow PVD with a round defect in the posterior vitreous cortex over the perifoveal area without vitreous attachment to the perifoveal area, no fellow eyes (0%) and one control eye (2.9%); type 5a, shallow PVD with no pseudo-operculum, no fellow eyes (0%) and four control eyes (11.8%); type 5b, shallow PVD with a pseudo-operculum, four fellow eyes (12.9%) and no control eyes (0%); and type 6, biomicroscopically relevant PVD, six fellow eyes (19.4%).

Conclusion: Types 3 and 5b developed only in fellow eyes. Type 2 developed most often in normal eyes and seemed to cause less foveal stress. Type 3 may show the basic pathogenesis of macular holes. Progression of type 5b after type 3 induces abortion of developing macular holes.

Keywords: fellow eye; idiopathic macular hole; optical coherence tomography; posterior vitreous detachment.

Figure 1

Classification of a shallow posterior vitreous detachment (PVD). Type 1, no PVD. Type 2, shallow PVD with a perifoveal vitreous attachment. Type 3, shallow PVD with pinpoint foveal vitreous traction. Type 4a, shallow PVD with a round defect in the posterior vitreous cortex over the perifoveal area with vitreous attachment to the perifoveal area. Type 4b, shallow PVD with a round defect in the posterior vitreous cortex over the perifoveal area without vitreous attachment to the perifoveal area. Type 5a, shallow PVD with no pseudo-operculum. Type 5b, shallow PVD with a pseudo-operculum.

Figure 1

Classification of a shallow posterior vitreous detachment (PVD). Type 1, no PVD. Type 2, shallow PVD with a perifoveal vitreous attachment. Type 3, shallow PVD with pinpoint foveal vitreous traction. Type 4a, shallow PVD with a round defect in the posterior vitreous cortex over the perifoveal area with vitreous attachment to the perifoveal area. Type 4b, shallow PVD with a round defect in the posterior vitreous cortex over the perifoveal area without vitreous attachment to the perifoveal area. Type 5a, shallow PVD with no pseudo-operculum. Type 5b, shallow PVD with a pseudo-operculum.

Figure 2

Movement of a detached operculum on the shallowly detached loose posterior vitreous cortex. Both optical coherence tomography images were obtained from the same patient. The left image was obtained just after ocular movement in the right image. Modified from Kakehashi.

Figure 3

The vitreoretinal relationship in a stage 2 macular hole. The detached loose posterior vitreous cortex shows some movement and traction to the operculum. Both optical coherence tomography images were obtained from the same patient. The left image is that of the central section of the macular hole, and the right image is the off-center section of the macular hole. Modified from Kakehashi.

Figure 4

Mechanism of a developing macular hole. The upper images show that the liquefied vitreous enters the subhyaloid space over the macular area through a crevice in the glial ring on the optic disc. The liquefied vitreous trapped in the subhyaloid space pushes the detached posterior vitreous cortex anteriorly with adhesion to the fovea (upper images) and subsequently causes development of a macular hole (lower images). Modified from Kakehashi.

Figure 5

Mechanism of developing ordinary posterior vitreous detachment (PVD). Wide vitreous attachment around the fovea is less stressful to the fovea. After development of a round break in the posterior hyaloid, a large amount of liquefied vitreous enters the subhyaloidal space hastening a biomicroscopic PVD. Modified from Kakehashi.