Spark ImageWise – 44

Recurrent Epiretinal Membrane

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

Case Description
A female, 56 years of age, came with complaints of gradual progressive diminution and distortion of vision in the right eye since 2 months. She was known case of systemic hypertension since 10 years and was on treatment. Her best corrected visual acuity was 6/18, N12 in right eye (RE) and 6/9, N6 in left eye (LE). Anterior segment examination showed presence of grade 1 nuclear sclerosis in both the eyes. Intraocular pressure recorded by Goldmann applanation tonometer was 16 mmHg in both eyes. 

Figure 1: Fundus photograph of right eye shows presence of an epiretinal membrane which is causing puckering of macula (green arrows). Increased tortousity of vessels can be seen in the superotemporal region (yellow arrow). The epiretinal membrane appears to be thicker in some parts. (blue arrows). 
Figure 2:
Fundus photograph of left eye showing normal optic disc and macula.
Figure 3 shows OCT image of line scan passing through fovea of right eye. There is loss of normal foveal contour and presence of hyper-reflective membrane (green arrow) which is lifting the retinal layers with significant distortion of the foveal contour. There is edema of the all retinal layers with some schitic changes in the inner nuclear layer (Yellow arrow). The traction is seen to be causing damage to the photoreceptor layer and ellipsoid zone in the foveal region (blue arrow).
Figure 4 shows OCT image of vertical line scan passing through fovea of right eye. There is loss of normal foveal contour and schitic changes are seen in the nerve fibre layer (blue arrows) and inner nuclear layer (yellow arrow). A hyper-reflective membrane can be seen above the retina. 
Figure 5 OCT of line scan passing through fovea of left eye showing normal foveal contour. A hyper reflective layer can be seen in the vitreous cavity suggestive of posterior hyaloid membrane. (Yellow arrow)

The patient was advised to undergo right eye pars plana vitrectomy with Epiretinal membrane peeling. She underwent surgery on 19/11/2021.

Figure 6a shows colour fundus photograph of right eye at 1 month follow up. The macula looks normal. The tortousity of vessels is still present in the superotemporal region (green arrows). Inspite of appropriate epiretinal membrane removal, there were signs of regrowth of the ERM which can be seen as a shiny patchy membrane in the superior and temporal part (blue arrow).
Figure 6b
shows colour fundus photograph of right eye at 3 months follow up. The view of the fundus was not as clear as on one month because of development of grade 2 nuclear sclerosis cataract in the right eye. There is growth of epiretinal membrane as shown in a comparison of increased tortousity (red arrowheads) of blood vessels in Fig. 6a and 6b.
Figure 7a shows the OCT line scan through macula on 7 day follow up after surgery. There is absence of the epiretinal membrane and the schitic changes are reduced. The foveal contour is showing some reformation (blue arrow). The retinal nerve fiber layer is showing some distortion due to long standing traction (yellow arrow). 
Figure 7b
shows OCT line scan through macula at 1 month follow up. There is significant resolution of the schitic changes of the inner nuclear layer and foveal contour is more organised (blue arrow).
Figure 7c
showsOCT line scan at 3 months follow up. There is a recurrence of epiretinal membrane which can be seen as a thin hyper-reflective membrane on the surface of the retina. Schitic changes can be seen in the inner nuclear layer (Yellow arrows). Few cystic spaces can be seen in the outer nuclear layer (blue arrow). Greater loss of photoreceptors and disruption of ellipsoid zone can be appreciated in the foveal region (Green arrow) compared to Fig. 7b. 

Discussion 

Our patient presented with complaints of diminution and distortion of vision in the right eye since 2 months and on examination there was presence of a hyper reflective membrane which was causing significant distortion of normal foveal contour (Fig 1,3). The schitic changes seen on the OCT scans (Fig 3,4) point towards presence of significant and long standing retinal traction. Based on the clinical and OCT findings, the patient was advised to undergo pars plana vitrectomy with epiretinal membrane peeling. Pars plana vitrectomy with membrane peeling is the standard treatment for surgical removal of the ERM, with reported rates of visual improvement ranging between 67% and 82%. Post vitrectomy patient did well and the vision improved to 6/12 from 6/18 one month following surgery. There was significant resolution of the schitic changes and the edema of retinal layers (Fig 7a, 7b). On 3 months follow up there was recurrence of epiretinal membrane with some schitic changes and loss of photoreceptors. (Fig 7c)

ILM peeling is a surgical technique commonly used today to treat various vitreoretinal disorders including epiretinal membranes, macular holes, macular puckers, diabetic macular edema, retinal detachment, retinal vein occlusions, vitreomacular traction, optic pit maculopathy, and Terson syndrome.

There is a difference in the opinion among surgeons regarding removal of ILM along with ERM. There is evidence in literature that removing the ILM helps reduce the chances of an ERM recurrence, as this removes any residual ERM cells that might have been left on the surface of the ILM, and that the ILM can act as a scaffold for their proliferation. 

The ILM plays an important role in retinal function because it is the basal lamina of Müller cells that are involved in the generation of ERG b-waves. The preservation of the acellular structure would help to preserve functions of the retina. Also ILM peeling is known to cause mechanical trauma to the retinal nerve fiber layer.

Our patient showed a significant epiretinal membrane that gave an appearance of growth from above the superotemporal vessels downwards towards the macula. There was also appearance of  three areas where the epiretinal membrane was thicker ( Fig. 1 blue arrows). All areas were dealt with surgically. Whether these areas are important in fostering the growth of the epiretinal membrane or represent irregular proliferation on the retinal surface is not so well understood. It is also important to recognise the importance of the effect of epiretinal membrane on the retinal layers, including the possible loss of foveal photoreceptors, which would affect the visual outcomes. Adequate surgical removal following the principles of  epiretinal membrane surgery was done. However the regrowth was rather rapid and  furthermore resulted in similar changes as were seen preoperatively. It is likely that the patient will require further management.

ReadWise:

  1. Díaz-Valverde A, Wu L. To peel or not to peel the internal limiting membrane in idiopathic epiretinal membranes. Retina. 2018 Sep 1;38:S5-11. doi: 10.1097/IAE.0000000000001906
  1. Semeraro F, Morescalchi F, Duse S, Gambicorti E, Russo A, Costagliola C. Current trends about inner limiting membrane peeling in surgery for epiretinal membranes. Journal of ophthalmology. 2015 Sep 3;2015. https://doi.org/10.1155/2015/671905
  2. Gelman R, Stevenson W, Prospero Ponce C, Agarwal D, Christoforidis JB. Retinal Damage Induced by Internal Limiting Membrane Removal. J Ophthalmol. 2015;2015:939748. doi: 10.1155/2015/939748.
  1. Sandali, Otman; El Sanharawi, Mohamed; Basli, Elena; Bonnel, Sebastien; Lecuen, Nicolas; Barale, Pierre-Olivier; Borderie, Vincent; Laroche, Laurent; Monin, Claire (2013). EPIRETINAL MEMBRANE RECURRENCE. Retina, 33(10), 2032–2038doi:10.1097/IAE.0b013e31828d2fd6 

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

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