Focal Choroidal Excavation (FCE)
Focal choroidal excavation (FCE) is a newly recognized clinical entity that is often incidentally found, and presents asymptomatic or with mildly decreased visual acuity in the affected eye. It has characteristic findings on optical coherence tomography (OCT) that can be used to distinguish it from other retinal lesions that may appear similar on ophthalmoscopy.
Focal choroidal excavation (FCE) is a recently characterized clinical entity first described by Jampol in 2006 and coined as a term by Margolis in 2011. FCE refers to a concavity of the choroid without local scleral changes that is often identified through a characteristic appearance on optical coherence tomography (OCT). This finding usually presents unilaterally and is found incidentally on exam, though exceptions to these patterns have been reported. The majority of FCE are thought to be congenital; however, the etiopathology of FCE remains a subject of active investigation. While most instances of FCE remain relatively stable over time and are managed with close observation, several complications requiring intervention, such as choroidal neovascularization and serous detachment, have been described.
The diagnosis and clinical characterization of FCE has been described through the use of optical coherence tomography (OCT). Several classification schemes have been suggested in the literature and used for categorizing FCE.
Conforming vs Non-conforming
The most commonly used classification system for FCE has been to define them as either: (1) conforming, where there is no separation between photoreceptor outer segments and the retinal pigment epithelium (RPE), and (2) non-conforming, where a space is identified between the two. In non-conforming FCE, the space between photoreceptors and RPE may contain heterogenous hyperreflective material, which has been attributed to inflammatory cells or degenerative debris.
Shinojima et al. have developed a classification scheme for FCE based on shape of the choroidal concavity itself, categorizing lesions as: (1) cone-shaped (2) bowl-shaped, or (3) mixed morphology. In their cohort, cone-shaped was the most common morphology, and bowl-shaped morphology was associated with RPE irregularities within the area of FCE, detected on indocyanine green angiography (ICGA).
The precise etiopathology of FCE remains to date unclear. It has been suggested that the clinical entity may represent a common morphological manifestation of multiple processes, which may be either congenital or secondarily acquired.
Congenital FCE are thought to be mostly stationary and not likely to be vision threatening, while secondary FCE may be related to a variety of conditions — including pachychoroid disease, chorioretinal inflammation, retinal dystrophies, and malignancy — which may require treatment to prevent complications and disease progression. In one study of patients aged <40 years old, only 3/1697 (0.18%) of eyes examined were found to have an FCE.
FCE has been associated with myopia, as well as pathology along the pachychoroid spectrum, most prominently with central serous chorioretinopathy (CSCR) and polypoidal choroidal vasculopathy. In one review, areas of choroidal thickening and dilated choroidal vessels were identified in the eyes of patients with FCE, even if they did not meet the requirements for diagnosis of a pachychoroid spectrum disorder. The entity has also been described more frequently in women than men, and more often in Asian populations, though the robustness of these associations remains unclear.
Additionally, case reports have described FCE in patients with a wide variety of pathologies. Age-related macular degeneration (AMD), for example, has been identified as a potential correlate of FCE, and some authors have investigated the potential link between the choroidal neovascularization characteristic of wet AMD, and the choroidal abnormalities seen in FCE. Other authors have suggested a link between the bestrophinopathies and FCE, with one study identifying FCE in 6% (2/33) of eyes with Best disease.
Infectious and inflammatory processes may also be linked with FCE — Epstein-Barr virus (EBV) infection and multiple evanescent white dot syndrome (MEWDS) have both been described in association with FCE.
As more patients are imaged with advanced posterior segment OCT, a more complete understanding of the clinical picture surrounding FCE is likely to emerge.
In several of the early descriptions of FCE, majority of patients had presented with mild to no visual symptoms. Since these reports, several case series have characterized the type and frequency of visual symptoms associated with FCE. In one case series of 37 eyes of 32 patients with FCE, 60% (18/32) complained of visual disturbances, either metamorphopsia, central scotoma, or decreased visual acuity. In another, 77% (17/22) patients complained of visual symptoms with 23% (5/22) being asymptomatic.
The functional ophthalmic exam may reveal reduced visual acuity in the affected eye, or may be within normal limits. Posterior segment exam may reveal a focal yellowish lesion that is often either foveal or parafoveal.
Color fundus photography is useful for documenting any findings that may have been detected on posterior segment examination, and also for co-localization with other imaging modalities. Careful fundus drawing from clinical examination may also be used to serve an equivalent clinical role. To assess RPE health in association with a suspected FCE, fundus autofluorescence imaging may be useful.
High resolution OCT remains the gold standard for diagnosis of FCE . While the first descriptions of FCE were made using time-domain OCT, spectral domain, enhanced depth, and swept-source OCT have been employed with great success for improved resolution and improved ability to evaluate underlying sclera and deep choroidal layers.
Angiography should be utilized to assess for choroidal neovascular membrane as well as RPE degeneration that might portend a worse visual outcome. Both indocyanine green angiography (ICGA) as well as fluorescein angiography (FA) have been previously utilized. OCT angiography (OCTA) may also be useful in the further evaluation of FCE-related vascular changes, especially if there is suspected associated neovascularization.
In the setting where full evaluation of the underlying sclera architecture may not be possible or findings may be difficult to interpret secondary to various imaging artifacts, contact b-scan ultrasonography may be employed.
The differential diagnosis of FCE can be broken down by anatomical location and testing. In the outermost layer, scleral thinning and ectasia — as with a posterior staphyloma — may cause changes to the topology of the associated choroid and can appear similar to FCE, though the margins of the lesion may have a more gradual slope.
Moving inward, conditions with choroidal thinning may present with imaging findings that could be mistaken for FCE. On ultrasonography, uveal tumors might appear similarly to FCE, as they will both have low acoustic reflectivity and appear as dark areas near the posterior pole. However, on OCT, uveal tumors are easily distinguishable from FCE.
Several entities may appear similarly to FCE on fundoscopic examination, including vitreomacular traction, impending macular hole, macular pseudohole, central serous choroidopathy, myopic schisis, soft drusen, and several congenital defects. Clinical features and characteristic imaging findings on OCT can be used to differentiate between FCE and these other conditions.
In cases of asymptomatic FCE without associated choroidal neovascular changes, observation without treatment is recommended. A slow increase in concavity size on OCT may be observed, but changes to concavity size might also be noted due to unavoidable variability in imaging modality such as slice orientation. Some authors have postulated that focal scar contraction and maturation may be responsible for the slow progression in concavity size observed in patients over time.
If there is evidence of lesion expansion or scleral thickening, a full evaluation for secondary causes of FCE should be undertaken to determine if any underlying process can be directly treated. For scleral thinning, surgical reinforcement of the sclera can be considered.
Additional complications may arise that require treatment, including secondary neovascularization and/or serous retinal detachment. If encountered, these may be managed depending on lesion location and sequelae, with anti-VEGF agents, verteporfin photodynamic therapy, or focal laser photocoagulation.
Several case reports have described a relatively stable course for FCE, whether symptomatic or asymptomatic. After initial evaluation for associated choroidal neovascular changes and secondary causes of FCE, it is appropriate to counsel patients with current data on the natural history of this finding. If patients develop complications of FCE such as neovascular choroidal changes or serous detachment, these should be treated accordingly.
- Jampol, L. M. et al. Diagnostic and therapeutic challenges. Retina 26, 1072–1076 (2006).
- Margolis, R. et al. The expanded spectrum of focal choroidal excavation. Arch. Ophthalmol. 129, 1320–1325 (2011).
- Braimah, I. Z., Rapole, S., Dumpala, S. & Chhablani, J. Focal Choroidal Excavation in Retinal Dystrophies. Semin. Ophthalmol. 33, 161–166 (2018).
- Shinojima, A., Kawamura, A., Mori, R. & Yuzawa, M. Morphologic features of focal choroidal excavation on spectral domain optical coherence tomography with simultaneous angiography. Retina 34, 1407–1414 (2014).
- Obata, R. et al. Tomographic and angiographic characteristics of eyes with macular focal choroidal excavation. Retina 33, 1201–1210 (2013).
- Verma, S. et al. Focal choroidal excavation: review of literature. Br. J. Ophthalmol. 105, 1043–1048 (2021).
- Shah, R. C., Gopalakrishnan, M., Goyal, A., Anantharaman, G. & Sethia, A. Focal choroidal excavation: Cause or effect? Indian J. Ophthalmol. 67, 696–698 (2019).
- Park, K.-A. & Oh, S. Y. The absence of focal choroidal excavation in children and adolescents without retinal or choroidal disorders or ocular trauma. Eye 29, 841–842 (2015).
- Chung, H., Byeon, S. H. & Freund, K. B. Focal Choroidal Excavation and its Association with Pachychoroid Spectrum Disorders: A Review of the Literature and Multimodal Imaging Findings. Retina 37, 199–221 (2017).
- Lim, F. P. M. et al. Prevalence and clinical correlates of focal choroidal excavation in eyes with age-related macular degeneration, polypoidal choroidal vasculopathy and central serous chorioretinopathy. Br. J. Ophthalmol. 100, 918–923 (2016).
- Kuroda, Y. et al. Association of focal choroidal excavation with age-related macular degeneration. Invest. Ophthalmol. Vis. Sci. 55, 6046–6054 (2014).
- Savastano, M. C., Rispoli, M., Di Antonio, L., Mastropasqua, L. & Lumbroso, B. Observed positive correlation between Epstein-Barr virus infection and focal choroidal excavation. Int. Ophthalmol. 34, 927–932 (2014).
- Hashimoto, Y., Saito, W., Noda, K. & Ishida, S. Acquired focal choroidal excavation associated with multiple evanescent white dot syndrome: observations at onset and a pathogenic hypothesis. BMC Ophthalmol. 14, 135 (2014).
- Liu, G.-H. et al. Focal choroidal excavation: a preliminary interpretation based on clinic and review. Int. J. Ophthalmol. 8, 513–521 (2015).
- Rajabian, F. et al. Optical Coherence Tomography Angiography Features of Focal Choroidal Excavation and the Choroidal Stroma Variations with Occurrence of Excavation. Retina 40, 2319–2324 (2020).
- Lim, F. P. M. et al. Evaluation of focal choroidal excavation in the macula using swept-source optical coherence tomography. Eye 28, 1088–1094 (2014).
- Cebeci, Z., Bayraktar, Ş., Oray, M. & Kır, N. Focal Choroidal Excavation. Turk J Ophthalmol 46, 296–298 (2016).
- Chawla, R., Mittal, K. & Vohra, R. Optical Coherence Tomography Angiography Study of Choroidal Neovascularization Associated With Focal Choroidal Excavation. Ophthalmic Surg. Lasers Imaging Retina 47, 969–971 (2016).
- Fuller, D. G., Snyder, W. B., Hutton, W. L. & Vaiser, A. Ultrasonographic features of choroidal malignant melanomas. Arch. Ophthalmol. 97, 1465–1472 (1979).
- Chung, C. Y., Li, S. H. & Li, K. K. W. Focal choroidal excavation-morphological features and clinical correlation. Eye 31, 1373–1379 (2017).
- Kovacs, K. D., Gonzalez, L. A., Weiss, S. J., Kiss, S. & Orlin, A. Focal Choroidal Excavation Expansion Following Treatment of Associated Choroidal Neovascular Membrane. Ophthalmic Surg. Lasers Imaging Retina 51, 54–57 (2019).
- Luk, F. O. J. et al. Focal choroidal excavation in patients with central serous chorioretinopathy. Eye 29, 453–459 (2015).
- Xu, H. et al. Focal choroidal excavation complicated by choroidal neovascularization. Ophthalmology 121, 246–250 (2014).
- Tang, W.-Y. et al. Focal choroidal excavation complicated with choroidal neovascularization in young and middle aged patients. Int. J. Ophthalmol. 12, 980–984 (2019).
- Pierro, L. et al. Natural course of symptomatic focal choroidal excavation. Ophthalmic Surg. Lasers Imaging Retina 46, 125–130 (2015).