A retinal pigment epithelium tear (RPE tear) is a condition in which the RPE suddenly tears and contracts in an area with pigment epithelial detachment (PED), exposing Bruch’s membrane and the choroid. It was first reported by Hoskin et al. in 1981.
Pigment epithelial detachment is a condition in which the basement membrane of the RPE and the collagen fiber layer within Bruch’s membrane are separated by exudate or blood. At the site where an RPE tear occurs, photoreceptor cells cannot survive, leading to abnormalities in visual function.
Ophthalmoscopically, it is observed as a crescent-shaped to half-moon-shaped reddish-brown lesion.
Main causes and incidence:
It can occur. In addition to central serous chorioretinopathy (CSC), polypoidal choroidal vasculopathy (PCV), pathologic myopia, and choroidal tumors, rare cases have been reported due to low intraocular pressure after glaucoma filtration surgery 1). Any condition associated with pigment epithelial detachment is a potential risk.
On dilated fundus examination, contracted and duplicated RPE areas and depigmented fundus with exposed choroid are observed. The most typical shape is crescent-shaped.
Takemoto et al. (2023) reported a case of RPE tear after Ex-PRESS filtration surgery for glaucoma 1). On postoperative day 13, an RPE tear along the superior arcade vessels and bullous retinal detachment in the inferior retina were observed. At 12 months, the RPE tear persisted, and tractional retinal folds due to subretinal proliferative tissue remained.
OCT is the most useful. It can clearly demonstrate discontinuity of the RPE band, scrolling of the free edge of the RPE, and a window defect in the area of the defect. Combining FA and FAF allows more detailed evaluation of the extent and activity of the tear. See the “Diagnosis and Examination Methods” section for details.
The main mechanisms of RPE tear are broadly divided into two categories.
A special mechanism after glaucoma filtration surgery has been reported as a chain: excessive intraocular pressure drop → choroidal circulatory disturbance → fluid accumulation in the suprachoroidal space → mechanical stretching and rupture of the RPE 1).
The morphological characteristics of pigment epithelial detachment and systemic factors constitute the main risks.
It may increase the risk. The natural incidence is 10–12.5%, while after anti-VEGF injection it is reported as 14–19.7%. The risk is particularly higher when the vertical height of pigment epithelial detachment exceeds 550 μm. However, the risk of discontinuing anti-VEGF treatment is usually greater, so continuation is the basic policy.
Each modality provides complementary information. A comprehensive evaluation combining multiple tests is important.
OCT
RPE band discontinuity: The linear hyperreflective band of the RPE is disrupted, allowing identification of the tear margin.
Scroll (rolled-up contraction): A characteristic finding where the free edge of the RPE is wavy and elevated.
Window defect: A hypo-reflective area where the choroid is visible through the RPE defect.
FA・FAF
In the case reported by Takemoto et al. (2023), a window defect (FA) was observed corresponding to the RPE tear site, and at 12 months, FAF showed persistent hypofluorescence in the RPE tear area 1).
Neovascular Age-Related Macular Degeneration
Continuation of anti-VEGF therapy: Continuation is recommended even after RPE tear occurs. There are no reports of worsening with treatment.
Small tears: RPE cells may re-cover, and visual function may partially recover.
Large tears (untreated): Subretinal fibrous plaque and scarring are likely to form.
Post-Glaucoma Surgery
Elevating intraocular pressure is the basis of treatment: Since excessive lowering of intraocular pressure is the cause, return the intraocular pressure to an appropriate range 1).
Transscleral scleral flap suture: Increases intraocular pressure and improves serous retinal detachment1).
Additional suture + viscoelastic injection into the anterior chamber: Adjunctive procedure for stabilizing intraocular pressure1).
CNV + pigment epithelial detachment
In the case reported by Takemoto et al. (2023), the retina reattached after intraocular pressure stabilized at 12–15 mmHg, and visual acuity at 12 months was 0.31). The long interval between RPE tear onset and IOP-elevating treatment is considered a contributing factor to residual tractional changes.
Prognosis is predicted by the size of the tear and foveal involvement.
| Grade | Tear Diameter | Visual Prognosis |
|---|---|---|
| Grade 1 | <200μm | Good |
| Grade 2 | 200 μm to 1 disc diameter | Relatively good |
| Grade 3 | >1 disc diameter | Moderate |
| Grade 4 | >1 disc diameter + fovea | Poor |
The size of the tear and involvement of the fovea are key. For small tears of Sarraf Grade 1-2, visual function may partially recover as RPE cells re-cover the area. On the other hand, Grade 4 (tear diameter >1 disc diameter with foveal involvement) has a poor visual prognosis. For details, see the “Sarraf Grading” section.
Exudative fluid accumulated within the pigment epithelial detachment increases hydrostatic pressure, causing rupture at the weakest point of the RPE. Once torn, the RPE undergoes elastic contraction and scrolls.
OCT studies have supported the mechanism by which contraction of type 1 CNV membranes beneath the RPE exerts traction on the RPE, leading to the formation of a tear.
In the case reported by Takemoto et al. (2023), the following chain was inferred 1): low intraocular pressure → choroidal circulation disorder → fluid accumulation in the suprachoroidal space → elevation of the retina and choroid toward the vitreous → mechanical stretching and rupture of the RPE → RPE barrier dysfunction → serous retinal detachment due to fluid movement.
Circulatory disturbance of the short posterior ciliary arteries (SPCA) due to arteriosclerosis is thought to predispose to ischemic optic neuropathy and, at the same time, impair the RPE barrier function through choroidal ischemia, increasing vulnerability to mechanical stretch 1).
The factors of pigment epithelial detachment morphology that determine the risk of RPE tear are summarized.
| Risk factor | Threshold |
|---|---|
| Pigment epithelial detachment vertical height (Sarraf criteria) | >550 μm |
| Pigment epithelial detachment vertical height (Chan criteria) | >400 μm |
| Duration of pigment epithelial detachment | Short (immature neovascularization) |
