Spark ImageWise 57

Spontaneous retinal pigment epithelial tear 

Dr. Shashank Somani, Dr. Sarang Lambat, Dr Prabhat Nangia, Dr. Vinay Nangia
Suraj Eye Institute, 559, New Colony, Sadar, Nagpur- 440001.

Case Description
A male, 74 years of age, presented with blurring of vision in left eye (LE) since 2 years. On examination his best corrected visual acuity (BCVA) was 6/18, N10 in right eye (RE) and 6/36p, N36 in the left eye (LE). His anterior segment examination was normal in both eyes with presence of immature cataract. His intraocular pressure (IOP) was 16 in both eyes.

Figure 1: Fundus photograph of RE shows normal disc with peripapillary atrophy with presence of multiple drusen in the macular area (blue arrow) along with patches of geographic atrophy (pink arrow)
Figure 2: Fundus photograph of LE shows normal disc with peripapillary atrophy and two hypo-pigmented areas (pink arrows) with increased visibility of choroidal vessels with an intervening bridge of hyperpigmentation (yellow arrow). The choroidal vessels can be seen in the area of atrophy (green arrow). Multiple drusen can be seen around the scar (blue arrow). 
Figure 3 – OCT line scan passing through macula of RE shows loss of foveal contour with presence of thin shiny membrane on the retinal surface suggestive of epiretinal membrane (blue arrow). A single soft druse is seen at the fovea (green arrow). There are multiple reticular pseudo-drusen seen in the perifoveal area (yellow arrow). 
Figure 4 – SD OCT line scan passing through the macula of LE shows hyper reflective material between the Bruch membrane and the RPE at the fovea possibly suggestive of a scarred CNVM (blue arrow). The RPE in this area is thrown into multiple folds (yellow arrow).  There is loss of photoreceptor layer nasal and temporal to the fovea along with dipping of outer retinal layers (green arrows). These areas also have absence of RPE leading to a hyperreflective choroid due to excess light transmission (fig 4b white arrow). A thin patchy hyper reflective membrane is seen on the surface of retina suggestive of epiretinal membrane (pink arrow).
Figure 5 – SD OCT line scan shows loss of photoreceptors can be seen on nasal and temporal side of the hyper-reflective area at fovea (green arrow). Undulations of the RPE (pink arrow) are seen temporally with an absent RPE near fovea suggestive of an RPE tear. There is increased visibility of the choroid in the area of absence of RPE.
Figure 6 – SD OCT vertical line scan passing through the fovea shows edge of RPE above (green arrow) and below (pink arrow) the fovea with the presence of RPE fold just above the fovea (blue arrow).
Figure 7– SD OCT line scan shows Undulations of the RPE temporally with an absent RPE of an RPE tear (blue arrow). A possible layer of encroaching RPE  can be seen from the nasal side of the RPE tear (green arrow). The approximate length of the RPE tear horizontally in this scan is approximately 3738um and the length of curled-up RPE is around 622um. 
Figure 8a and 8b – shows schematic presentation of possible direction of RPE tear and retraction in this patient.
Figure 9a – Shows Fundus auto fluorescence image showing hypo-fluorescent patch suggestive of absence of RPE (green arrows). A bunched up patch  of RPE can be seen temporally (yellow arrow). 
Figure 9b – Left eye FFA in late arteriovenous phase shows presence of a sharply delineated, hyper-fluorescent signal in the RPE tear area (green arrows) with  adjacent patch of blocked fluorescence (read arrow).
Figure 10a – En-face image of LE at the level of chorio-capillaries showing hypo reflective patches at the locations of RPE tear (green arrows) and a dark  patch adjacent to it suggestive of curled up RPE in that area (red arrow).
Figure 10b – Left eye OCTA slab at the level of chorio-capillaries showing medium sized choroidal vessels in the area of RPE tear (green arrow) and absence of vascular signals in the adjacent area where there’s curled up RPE,  blocking the signals from the vessels below it (red arrow).
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Discussion

A retinal pigment epithelial tear can occur due to various eye conditions. It occurs more commonly in a vascularised PED due to neovascular AMD. It can also arise after treatment of a choroidal neovascular membrane with laser photocoagulation, transpupillary thermotherapy or photodynamic therapy with verteporfin. The rate of spontaneous tear in a vascularized pigment epithelial detachment is reported to be between 10%  and 12.5 %. With the use of anti-VEGF agents, the incidence of RPE tear is increasing and has been found to be as high as 33%. It can lead to a further decrease in visual acuity despite treatment and hence it is important to be able to identify an RPE tear when it occurs.

Size of the PED and basal diameter are recognized risk factors for the development of RPE tear. Studies have reported that the tear happens when the neovascular process is fresh and in one of the studies, it was found that there is an increased chance of tear formation if the duration of the PED is less than 4.5 months. Increased hydrostatic pressure and CNVM contraction under the RPE are the most acceptable mechanisms responsible for the formation of the RPE tears. Mouallem and Sarraf et. al postulated that a double RPE tear may occur on two opposite sides of a vascularised PED because of contractile forces by a choroidal neovascularization adherent to the posterior surface of the detached RPE. The CNV spans a larger area below the RPE and the hydrostatic pressure is not completely released with a single tear on one side. The edge opposite to the tear probably still has some susceptibility and it may get torn with further injection and subsequent CNV contraction.

Our patient presented with a significantly reduced vision of 6/36 in the left eye. The left eye fundus photograph (Fig 2) gave an impression of large areas of geographic atrophy with significant pigmentation in between the two main patches. The RE also showed a small  patch of geographic atrophy associated with drusen and reticular pseudodrusen ( Fig 1, and Fig 3 a and b) 

Initially, the appearance of the elevated area seen in Figure 4b (blue arrow) led to the suspicion that this was a partially active choroidal neovascular membrane. The patient underwent an anti-VEGF injection, however, there was no response.    

The patient was diagnosed to have a spontaneous retinal pigment epithelial tear,  which is known to occur in conditions that involve diseases affecting the retinal pigment epithelium.  Initially, the two areas Fig 2 (pink arrow) and Fig 4a appeared to be patches of geographic atrophy. However, on further assessment, it appeared that these areas lacked retinal pigment epithelium. The retinal pigment epithelium had retracted inferiorly from the superior bare patch and superiorly from the inferior bare patch. ( fig 6a blue arrow and Fig 6b blue arrow). This resulted in the classic dividing band of retinal pigment epithelium in between the two bare patches ( Fig 6a blue arrow, Fig 2 yellow arrow)  which consisted of rolled-up RPE. ( Fig 6b blue arrow). The Retinal pigment epithelium had also retracted temporally and appeared as a rolled-up pigmented edge ( Fig 2 and fig 7b blue arrow). 

The RPE tear had a maximum width of 3738 microns (fig 7b). The Rolled up RPE when measured segmentally appeared to be 622 microns in length (Fig 7b) This indicates that the RPE not only retracts but may also have contractile properties that allow it to shrink in linear dimension besides folding up (Fig 7b). 

Autofluorescence showed the presence of dark patches representing the areas devoid of the retinal pigment epithelium. The FFA shows the two areas of bare RPE lighting up like a flare. ( Fig 9b green arrow). The band of RPE in between and on the temporal sides showed blocked fluorescence (Fig 9b red arrow).

En-face imaging showed the presence of medium and large choroidal blood vessels in the area of RPE loss and a dark web-shaped patch of pigment (Fig 10a). On OCTA the choroidal Haller’s and Sattler’s layer was visible in the choroid in the area bare of RPE and also in the area nasal to it. However, choroid vessels were not imaged in the area where RPE had bunched up (Fig 10b) probably because of the nature of the RPE. 

Changes of geographic atrophy with loss of outer retinal layers including the photoreceptors and outer nuclear layer with a downward movement of the outer plexiform layer are seen in our patient. There is also a loss of the outer plexiform layer (Fig 6b and Fig 7b). The presence of geographic atrophy in the RE is indicative that a similar process must have been set in the left eye. However, in the left eye, it was a precursor and may have contributed through a degenerative process to the retinal pigment epithelial tear. 

The prognosis in these patients would be very guarded. The case is unusual because  the retinal pigment epithelial tear occurred  in the absence of  classical predisposing factors and also because of the direction of RPE movement following the tear ( Fig 8 ) 

ReadWise

  1. Clemens CR, Eter N. Retinal Pigment Epithelium Tears: Risk Factors, Mechanism and Therapeutic Monitoring. Ophthalmologica. 2016;235(1):1-9. doi: 10.1159/000439445. Epub 2015 Oct 22. PMID: 26489018. DOI: 10.1159/000439445
  2. Ersoz MG, Karacorlu M, Arf S, Sayman Muslubas I, Hocaoglu M. Retinal pigment epithelium tears: Classification, pathogenesis, predictors, and management. Surv Ophthalmol. 2017 Jul-Aug;62(4):493-505. doi: 10.1016/j.survophthal.2017.03.004. Epub 2017 Mar 21. PMID: 28336128. DOI: 10.1016/j.survophthal.2017.03.004 .
  1. Sarraf D, Reddy S, Chiang A, Yu F, Jain A and al.A new grading system for retinal pigment epithelial tears. Retina. 2010 Jul- Aug;30(7):1039-45. doi: 10.1097/IAE.0b013e3181cdf366

Correspondence 
Dr. Sarang Lambat
MS, FRF
Consultant
Vitreoretinal services
Suraj Eye Institute
Nagpur
Email – education@surajeye.org

QuizWise

Q 1 – One or more of the following are true for retinal pigment epithelial tears. 

  1. All patients with Choroidal neovascularization will get a retinal pigment epithelial tear
  2. Retinal pigment epithelial tears are often associated with intravitreal Anti VEGF injections
  3. Retinal pigment epithelial tears  always heal by sliding and proliferation of  the epithelium
  4. One can predict which patient with CNV will  develop a RPE tear. 

Q 2 – RPE tears may occur in one or more of the above. 

  1. Central serous retinopathy
  2. Traumatic chorioretinopathy
  3. Glaucoma surgery
  4. High myopia
  5. Geograpic atrophy
  6. Toxemia of pregnancy

 

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