Optical coherence tomographic findings in highly myopic eyes

Abstract

Optical coherence tomography (OCT) has enhanced our understanding of changes in different ocular layers when axial myopia progresses and the globe is stretched. These findings consist of dehiscence of retinal layers known as retinoschisis, paravascular inner retinal cleavage, cysts and lamellar holes, peripapillary intrachoroidal cavitation, tractional internal limiting membrane detachment, macular holes (lamellar and full thickness), posterior retinal detachment, and choroidal neovascular membranes. In this review, recent observations regarding retinal changes in highly myopic eyes explored by OCT are described to highlight structural findings that cannot be diagnosed by simple ophthalmoscopy.

Keywords: High Myopia; OCT; Optical Coherence Tomography.

Figure 1

Difference in vertical and horizontal OCT cross-sections in a myopic eye with posterior staphyloma.

Figure 2

C-scan optical coherence tomography in a myopic eye shows incomplete detachment of the posterior cortical vitreous with persistent attachment and traction on the temporal part of the macula (red arrowheads). The red dots show the area of the C-scan.

Figure 3

Rigid and taut retinal vessels (red arrows) may contribute to creation of retinal schisis in myopic eyes.

Figure 4

Mirror-image artifact in a highly myopic eye. The deeper the staphyloma, the more the distortion caused by such artifacts on cross-sectional images.

Figure 5

Changes in peripapillary detachment in pathologic myopia (PDPM) consist of a yellow-orange lesion in the periphery of the myopic crescent (black arrows). Cross-sectional optical coherence tomography shows a longitudinal scan of the same patient which clearly identifies hollow spaces adjacent to the disc.

Figure 6

Peripapillary detachment in pathologic myopia localized to the inferior part of the optic disc (arrows). Incomplete posterior vitreous detachment with attachment of the posterior cortical vitreous to the optic disc head and paravascular cysts are also noted. The mirror image artifact resulted in a segmentally inverted image.

Figure 7

A SLO-OCT view of the optic nerve head in a myopic eye. Peripapillary cavitation is a hollow, dark space in the inferior part of optic nerve head (white arrow on OCT and red arrows on SLO sections of the picture).

Figure 8

A myopic person with small peripapillary choroidal cavitation adjacent to the optic disc.

Figure 9

Peripapillary detachment in pathologic myopia represents as hollow spaces beside the root of the optic disc (green arrows).

Figure 10

Typical small paravascular cyst located adjacent to major retinal vessels deep in the retina without communication with the vitreous cavity.

Figure 11

Longitudinal optical coherence tomography shows multiple paravascular cysts adjacent to main retinal vessels.

Figure 12

Two vascular microfolds are noted near the optic disc along large retinal vessels. Irregular staphyloma results in a bizarre shaped longitudinal optical coherence tomography image. Small extension of peripapillary detachment with a hollow space at the base of the staphyloma is also noted.

Figure 13

A large paravascular lamellar hole in a pathologic myopic eye. At the right side of the hole, an area of peripapillary detachment is notable.

Figure 14

A paravascular lamellar hole which may be due to unroofed paravascular cysts. Retinal schisis is also noted underneath.

Figure 15

Longitudinal optical coherence tomography crossing the central fovea. It seems that condensed posterior cortical vitreous and incomplete separation from inner retinal layers (red arrows) are responsible for tractional foveal thickening and early schisis.

Figure 16

Longitudinal optical coherence tomography in a myopic eye shows more advanced tractional maculopathy resulting in separation of the inner foveal layer and lamellar macular hole formation.

Figure 17

Optical coherence tomography of the inferior macula in a myopic eye shows tractional internal limiting membrane detachment which bridges over inner retinal layers. In this example it resembles a taut cortical vitreous which is not able to expand with the outer parts of the retina.

Figure 18

Differentiation between dense cortical vitreous or epiretinal membrane and tractional internal limiting membrane detachment.

Figure 19

This figure clearly shows the multilayered nature of the posterior cortical vitreous and its tight attachment to the internal limiting membrane (ILM) in myopic eyes (arrow heads) as it merges with the ILM (arrows).

Figure 20

Early myopic foveoschisis may demonstrate as outer retinal layer thickening (yellow arrows) of low reflectivity.

Figure 21

This image shows outer macular schisis (red arrows) accompanied by internal limiting membrane detachment (white arrow heads) extending to the fovea (white arrow).

Figure 22

Color fundus photographs of a high myopic patient with mild foveoschisis. The longitudinal B-scan OCT view reveals mild outer retinal layer dehiscence in the fovea (white arrows) with tractional epiretinal membrane, ILM detachment or condense posterior vitreous (arrow heads) above it which may be responsible for these changes.

Figure 23

Posterior retinal detachment in a highly myopic eye without macular hole. Detached neurosensory retina shows a corrugated pattern at its outer surface which may be due to lack of outer segment phagocytosis by the retinal pigmented epithelium layer, resulting in outer segment elongation.

Figure 24

SLO-OCT image of a myopic posterior pole with chorioretinal atrophy. Extreme retinal atrophy, posterior staphyloma, vascular microfolds, and parafoveal retinoschisis result in macular hole formation, and a small localized posterior retinal detachment are present.

Figure 25

Color fundus photograph of a myopic eye with decreased vision of a few weeks’ duration due to choroidal neovascularization. A grey elevated mass is noted in the parafoveal area (arrows).

Figure 26

Retinal topographic map by optical coherence tomography reveals localized retinal elevation at the area of neovascularization.

Figure 27

SLO-OCT examination of that area reveals an active neovascular growth under the retina which blends with outer retinal layers and results in mild disorganization of that area. The amount of subretinal fluid collection is minimal.

Figure 28

Another example of choroidal neovascularization in the extrafoveal area of a highly myopic patient (optical coherence tomography and fluorescein angiography). The inner surface of the active neovascular tuft is feathery with medium reflectivity. Evolution to inactivation and scar formation is accompanied by increased reflectivity and sharpness of the edges of the lesion.

Figure 29

Another example of active myopic choroidal neovascularization with a neovascular membrane under the fovea together with subretinal fluid collection and destruction of underlying Bruch’s membrane (white lower arrow).

Figure 30

End-stage neovascular membrane with scar formation and lamellar macular hole which may be the result of tractional internal limiting membrane detachment or the consequence of inactivation of neovascular membrane. Macular hole in this case (white arrows) may be the result of atrophic changes after the occurrence of subfoveal choroidal neovascularization.

Figure 31

SLO, optical coherence tomography (OCT) and color fundus photography of a highly myopic eye with posterior retinal detachment and a full thickness macular hole. The detachment is limited to the posterior pole which is clearly evident on OCT. Multiple cystic spaces at the edges of the hole indicate chronicity of the detachment. The margins of the detachment are shown by green arrowheads in the color fundus photograph.

Figure 32

An early lamellar macular hole due to expansion of the posterior pole. Clefts in the middle retinal layer (red arrow heads) are the signs of early schisis or lamellar hole formation.

Figure 33

Tractional macular band (red arrows) may contribute to the central foveal cleft (deep lamellar macular hole) in this SLO-optical coherence tomography.

Figure 34

Full-thickness macular hole which may be due to tractional retinal components that separate central foveal tissues (red arrows).

Figure 35

Full-thickness macular hole (red arrow) which may be due to globe expansion separating retinal tissues in the fovea.

Figure 36

Due to vertical scan orientation of the longitudinal optical coherence tomography, the posterior staphyloma cannot be appreciated, but choroidal thinning (to about half-normal thickness) is visible (white arrows).

Figure 37

Due to globe expansion in pathologic myopia, apertures of the sclera which are perforated by ciliary vessels are visible (black arrows) as large-diameter, full-thickness scleral defects together with outward displacement of the retina. This is usually accompanied by retinal pigmented epithelium/choroidal atrophy.