Keywords epiretinal membrane - foveal herniation - macular surgery - optical coherence tomography
- flower-petal peeling
Schlüsselwörter epiretinale Membran - foveale Herniation - Makulachirurgie - optische Kohärenztomografie
- Blütenblatt-Peeling
Introduction
Epiretinal membranes in younger patients are often thicker and more firm compared
to elderly. Surgical removal of these membranes, especially when they cause retinal
distortion over the macula, is usually recommended [1 ]. Foveal herniation occurs when neuroretinal tissue protrudes through and above the
level of an epiretinal membrane, usually from a small central defect in a taut membrane,
causing irregularities in the inner retinal architecture. The pathogenesis of foveal
herniation is still unknown, though it is likely attributable to the centripetal contraction
of the epiretinal membrane (ERM). Moreover, the thinning of the prefoveolar internal
limiting membrane (ILM) may further exacerbate this process by reducing the structural
support for the retina in that area [2 ], [3 ].
The aim of this report is to describe the visual symptoms and spectral-domain optical
coherence tomography (SD-OCT) findings associated with foveal herniation with idiopathic
epiretinal membrane and to evaluate the postoperative visual, anatomical, and surgical
outcomes.
Case Presentation
We present the case of a 37-year-old Caucasian male with no prior ocular history,
who came to us reporting metamorphopsia and a persistent decrease in visual acuity
in his left eye, which had been ongoing for several months. At the time of initial
examination, his left eye best-corrected visual acuity (BCVA) was documented as 0.05
decimal. Anterior segment examination of the left eye appeared within normal limits;
however, dilated fundoscopy revealed the presence of an epiretinal membrane accompanied
by a notable concentric ring of foveal tissue prolapse ([Fig. 1 a ]). Fundus autofluorescence showed a marked hypofluorescence in the foveal region
([Fig. 1 b ]). SD-OCT imaging was performed, which showed significant foveal tissue protruding
through and above the ERM, indicating severe foveal herniation of the ganglion cell
complex without marked alterations of the outer retinal segments ([Fig. 2 ]).
Based on these clinical and imaging findings, the patient was diagnosed with idiopathic
ERM with associated foveal herniation. To address this condition, the patient was
scheduled for a surgical intervention involving 25-gauge pars-plana vitrectomy with
ERM peeling and air tamponade. A meticulous flower petal peeling technique was applied
in order to minimize traction on the foveal tissue. Postoperatively, the patient demonstrated
a gradual restoration of normal foveal anatomy ([Fig. 3 ]), accompanied by a marked improvement in visual function. Three months after surgery,
BCVA improved to 0.6 decimal, and to 0.8 decimals at 12 months, indicating a significant
recovery from the preoperative condition.
Fig. 1 a Fundus photography of the left eye revealing central foveal alteration. b Fundus autofluorescence showing a marked hypofluorescence in the foveal region.
Fig. 2 a Infrared image showing retinal wrinkles at the posterior pole. b Different SD-OCT scans showing the foveal tissue protruding through and above the
epiretinal membrane, demonstrating the severe foveal herniation.
Fig. 3 Horizontal (a ) and vertical (b ) macular SD-OCT scans at 3 months postoperatively.
Discussion
This case report shows a rare finding of foveal herniation with idiopathic epiretinal
membrane. The patientʼs follow-up demonstrates visual improvement and gradual resolution
of foveal herniation after ERM peeling and shows that it may take few months for the
foveal bulge to decrease in height. Notably, this case highlights the fact that when
the outer retinal layers remain intact or with only mild alteration, delayed but notable
visual recovery is achievable.
Herniation of retinal tissue through a small epiretinal membrane hole is a relatively
rare finding and was first reported in 2011 by Francis et al. as a perifoveal circumferential
contraction of the ERM and the subsequent prolapse of the foveola centrally [3 ]. In the literature, foveal herniation with ERM is rare, usually described as unilateral,
and information about the characteristics of this entity and the postoperative outcomes
after ERM peeling surgery is limited. Most cases present a good visual outcome after
surgical intervention [4 ]. The pathogenesis of foveal herniation remains unclear; however, our findings suggest
that the protrusion of foveal tissue and the ganglion cell complex observed in this
case may result from retinal edema due to traction exerted by the ERM. This traction
likely induces herniation in areas not covered by the membrane.
Our patient experienced a remarkable improvement in BCVA (from 0.05 to 0.6 decimals)
following ERM peeling. In the literature, various prognostic factors have been identified
in relation to visual acuity outcomes after idiopathic ERM peeling. Key factors include
preoperative visual acuity, symptom duration, and SD-OCT findings such as retinal
thickness and the integrity of outer retinal layers [5 ]
[6 ]
[7 ]
[8 ]. In our case, foveal herniation was limited to the inner retinal layers and ganglion
cell complex with an intact outer retina, so we attribute the favorable postoperative
visual outcome primarily to the preoperative integrity of the outer retinal layers,
as shown on the baseline SD-OCT scans, including an intact and uninterrupted ellipsoid
zone. Also, in a case similar to ours, Oellers and Elliot suggested that a substantial
visual improvement following membrane
peeling with foveal herniation may be explained by the combination of an intact outer
retina and the postoperative normalization of the inner retinal layer anatomy [9 ]. Another factor that might be crucial for visual recovery is the ERM peeling technique.
In our case, the meticulous flower petal peeling technique was applied in order to
minimize traction on the foveal tissue. This technique involves segmenting the ERM
into multiple small “petals,” initiating peripherally to the fovea and gradually advancing
toward it. We believe that this method allows for controlled and sectional removal
peeling of the ERM around the fovea, reducing the risk of additional stress or focal
traction on the foveal protruding tissue. By carefully avoiding direct manipulation
of the foveal region, the flower petal peeling technique can potentially reduce the
risk of exacerbating the herniation and support a more favorable visual outcome.
In conclusion, this case report shows a rare finding of foveal herniation with ERM.
This atypical presentation has an important clinical relevance in order to give knowledge
to clinicians about the possibility of these findings, with the goal to prevent erroneous
diagnosis and unnecessary treatments. We demonstrate the visual improvement and gradual
resolution of foveal herniation with SD-OCT images after ERM removal, and the images
convey that it may take a few months for the foveal bulge to decrease in height. When
the outer retinal layers are normal, visual recovery, though delayed, is appreciable.
