Fig. 8.1
(a) Image of wide macular staphyloma in high myopia by spectral-domain OCT. The chorioretinal curvature is not well-delineated. (b) Image of wide macular staphyloma from the same patient as (a) by swept source OCT. The whole posterior pole area is documented and the central fovea is on the slope (arrowhead). The detail structure of the thin choroid is also visualized well (arrows). (c) SS-OCT image of inferior staphyloma. Note that the central fovea is at the upper edge of staphyloma (arrowhead) and the ellipsoid zone line is disrupted
8.2 Myopic Traction Maculopathy
Myopic traction maculopathy (MTM), including retinal schisis (RS) and macular hole retinal detachment (MHRD), is a pathologic myopia-related complication caused by some mechanisms with traction as a common pathway. The diagnosis of MTM by slit-lamp biomicroscopy was very difficult [16, 17]. The introduction of OCT enables one to detect the specific structural features of MTM in detail [6, 16, 18].
8.2.1 Retinal Schisis
Retinal Schisis, also called myopic foveoschisis, is one of the pathological conditions of MTM and is estimated to affect between 9 and 34% of highly myopic eyes with posterior staphyloma [6, 18, 19]. The SS-OCT findings of RS include foveal detachment, lamellar macular holes, macular epiretinal membrane, and vitreoretinal traction (Fig. 8.2).
Fig. 8.2
(a) SS-OCT image shows outer retinal schisis (asterisks) and vitreoretinal traction (arrowheads). (b) Preoperative SS-OCT image shows outer retinal schisis (arrows), waving of the outer retina (arrowheads), and foveal detachment with a macular hole. The retinal pigment epithelium layer could not be included due to the excessive height of retinal detachment (asterisk). (c) SS-OCT image at 1 month after vitrectomy with inverted ILM flap technique shows reattachment of the retina. Note that a thin tissue is observed in the foveal center and thus the macular hole is closed (arrowhead). (d) Preoperative SS-OCT image shows a full thickness macular hole (arrowhead) with an epiretinal membrane, retinal schisis (arrow) and retinal detachment. (e) SS-OCT image at 2 years after vitrectomy with conventional ILM peeling shows reattachment of the retina (arrowhead). An ellipsoid zone at central fovea is visible (arrowhead)
8.2.2 Macular Hole Retinal Detachment
Macular hole retinal detachment is considered to be the final stage of progressive MTM. MHRD occurs almost exclusively in high myopes and causes severe visual impairments. The main causative factors of MHRD are both anteroposterior and tangential tractions in the macula area, which is potentially accelerated by the progression of posterior staphyloma [18, 20].
Vitrectomy with gas endotamponade is currently the first-line treatment [21]. Various techniques, such as using silicon oil tamponade, laser around macular hole (MH), internal limiting membrane (ILM) peeling, and inverted ILM flap technique, have been reported [22, 23]. Some studies have shown better anatomic results with ILM peeling since this guarantees complete removal of epiretinal tractions and a more flexible retina [24, 25]. However, the success rate of surgery for MHRD is lower than that of conventional rhegmatogenous retinal detachment, and revisions are sometimes required [22] (Fig. 8.2).
8.3 Choroidal Neovascularization
Myopic CNV often causes severe visual impairment [26]. Myopic CNV is sometimes associated with subretinal dark pigment migration or hemorrhage and develops into chorioretinal atrophy [27]. It has been reported that 13% of eyes with lacquer cracks develop myopic CNV, and the high myopic eyes with lacquer cracks have less choroidal thickness than those without lacquer cracks [8, 28]. Similarly, high myopic eyes with CNV might have less choroidal thickness than those without CNV [29]. Intravitreal anti-VEGF therapy is widely accepted as a first-line treatment of myopic CNV, and recent studies have demonstrated beneficial visual outcomes (Fig. 8.3) [30–32].
Fig. 8.3
(a) Fluorescent fundus angiography of myopic CNV. The leakage is observed at the site of the disruption of retinal pigment epithelium documented in (b). (b) SS-OCT image shows the subretinal fluid (asterisk), subretinal hemorrhage, disruption of retinal pigment epithelium (arrowhead), and the thin choroidal thickness (arrow). (c) SS-OCT image at 1 month after intravitreal ranibizumab injection shows the regression of CNV and resolution of subretinal fluid
8.4 Intrachoroidal Cavitation
Intrachoroidal cavitation (ICC) is a yellow-orange peripapillary area at the inferior border of the myopic conus. Prior to the introduction of OCT, this lesion was described as a peripapillary detachment in pathologic myopia (PDPM) [33]. The main OCT feature of ICC is a large intrachoroidal hyporeflective space (Fig. 8.4) [34].
Fig. 8.4
A large intrachoroidal hyporeflective space is observed adjacent to the optic nerve (arrowheads)
8.5 Dome-Shaped Macula
Dome-shaped macula (DSM) is first described as an anterior protrusion of the macula in high myopia with posterior staphyloma [35]. DSM sometimes can cause visual impairment due to associated myopic CNV or serous macular detachment (Fig. 8.5) [36].
Fig. 8.5
SS-OCT image shows an anterior protrusion of the macula with posterior staphyloma (arrows). The sclera is observed as a highly reflective tissue (arrows) outside of the very thin choroid. The fibers of Tenon’s capsule are also well observed (arrowheads)
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