Issue link: http://retinalphysician.epubxp.com/i/783300
40 R E T I N A L P H Y S I C I A N . C O M | N O V E M B E R / D E C E M B E R 2 0 1 6 determined from ophthalmoscopic appear- ances, which might be rather subjective. e Author's Modified Classification To overcome these issues with Curtin's clas- sification, the author 4 determined the type of staphylomas based on the shape of the entire eye using scans by 3D MRI. To simplify Curtin's classification, the author analyzed only the contour of the outermost border of staphylomas. is resulted in Curtin types VI to X being placed into the type I category. e staphyloma type is renamed according to its location and distribution; this facilitates with memoriza- tion. (Figure 7). In Pathologic Myopia, Spaide published images of staphy- lomas that do not belong in any type in Curtin's classifica- tion. 2 us, the further improvement of imaging technologies of eye shape (like widefield OCT) may reveal a much more complicated pattern of staphylomas, and new classification is expected to be made according to such future modalities. Among staphylomas, the wide macular type was by far the most common (74% of all staphylomas) (Figure 8). e narrow macular type followed (14%) (Figure 9). Other types are rare, and they include inferior staphyloma (3%) and nasal staphyloma (2%). CLINICAL SIGNIFICANCE OF STAPHYLOMAS Eyes with posterior staphyloma have been reported to have worse outcome functionally and structurally than the eyes with simple axial myopia but without staphyloma. e author 4 investigated how staphylomas affect the functional and anatomical properties of the eye and showed that eyes with staphylomas had significantly worse BCVA and more eyes had patchy chorioretinal atrophy and myo- pic choroidal neovascularization than eyes without evident staphylomas. ese data confirmed that the formation of staphylomas had a significant unfavorable effect on patients with pathologic myopia. is detrimental effect might be due to the great expan- R E T I N A L P H Y S I C I A N | J A N U A R Y / F E B R U A R Y 2 0 1 7 40 sion of the area of the posterior pole of the eye, as suggested by Spaide. 2 As shown in Figure 1, the posterior fundus is stretched even by a simple elongation of the axial length in axial myopia, but the area could not be doubled because the equatorial region mainly elongates and contributes to axial length increase. However, when an outpouching develops, the original area including macula and optic nerve could be greatly expanded and could double. So, it is easy to expect that the mechanical expansion of the occupied area is no comparison between the eyes with and without staphylomas. TOWARD FUTURE TREATMENTS TARGETING STAPHYLOMAS Future therapeutic approaches for pathologic myopia would be to prevent and treat the staphylomas, because staphylomas may be a cause of worse visual and anatomical outcome for patients with pathologic myopia. Although some lesions of myopic maculopathy have treatment options (like antivascu- lar endothelial growth factor therapies for myopic choroidal neovascularization and surgeries for myopic traction macu- lopathy), visual improvements are limited in most cases. In addition, other lesions (chorioretinal atrophy and optic nerve damage) have no treatments to improve vision. us, preventive therapies targeting staphylomas before seri- ous complications occur would be ideal and expected. ese could include scleral collagen crosslinking, 11 scleral reinforce- ment, and scleral regeneration. Shinohara and colleagues 12 recently succeeded in preventing myopia in rat models of experimental myopia by regenerating scleral collagen by an implantation of skin fibroblasts. POSTERIOR STAPHYLOMA IN PATHOLOGIC MYOPIA Figure 5. Ultra-widefield OCT image of an eye with pathologic myopia. Scleral curvature is observed in a very wide range (16 mm wide and 5 mm deep), wide enough to cover the entire extent of wide staphyloma. Figure 6. Curtin's classification of posterior staphyloma. Types I through V are classified as primary staphyloma, and types VI through X are classified as combined staphyloma. e laer is a combination of primary staphylomas. Figure 7. e author's classification of posterior staphyloma. Only the contour of the outermost staphyloma border is considered. is results in the Curtin types VI to X being placed into the type I category. Also, the staphyloma type has been renamed based on its location and distribution; this facilitates memorization.