Inactive (most cases)
Well-demarcated yellow-white lesion: it has a clear outline and a stable appearance.
Orange halo: the orange border around the lesion is characteristic and reflects partial choroidal thinning1).
Focal Scleral Nodule
Key points at a glance
Section titled “Key points at a glance”1. What is focal scleral nodule?
Section titled “1. What is focal scleral nodule?”A focal scleral nodule is a yellow-white, raised, round non-neoplastic lesion that originates in the sclera. It is typically located posterior to the equator, and because the overlying choroid becomes thin, it is seen on fundus examination as a yellow-white lesion.
The naming history is as follows.
- 1997: Hong et al. first reported it as unifocal helioid choroiditis.
- 2002: Shields et al. reviewed 60 cases and named it solitary idiopathic choroiditis. This was because the clinical appearance resembled an inactive choroidal granuloma, but there was no evidence of a systemic granulomatous disease2).
- 2020: Fung et al. published a retrospective study of 63 patients based on findings from enhanced depth imaging optical coherence tomography (EDI-OCT) and swept-source optical coherence tomography (SS-OCT). They proposed focal scleral nodule because the lesion originates in the sclera rather than the choroid, and no choroiditis was seen1)3).
- 2021: Duignan et al. reported similar findings and proposed the name idiopathic scleroma1).
The age at onset ranged widely from 3 to 83 years, and it may be more common in women and White patients. About one-third of patients are asymptomatic at diagnosis2).
Q
Why was focal scleral nodule previously called choroiditis?
A
Before optical coherence tomography became available, the lesion was thought to arise from the choroid. Enhanced depth imaging optical coherence tomography and swept-source optical coherence tomography confirmed an intrascleral origin, and the choroidal changes were found to be thinning secondary to mechanical compression by the lesion, so the name was changed in 2020.
2. Main symptoms and clinical findings
Section titled “2. Main symptoms and clinical findings”Symptoms
Section titled “Symptoms”Most focal scleral nodules are asymptomatic and are found incidentally during routine fundus examination. If symptoms are present, the following are common.
- Floaters and blurred vision: These are the most common symptoms.
- Central scotoma: In an 18-year-old male case, the chief complaint was a central scotoma in the right eye2).
- Paracentral scotoma: In a 34-year-old female case, enlargement of a paracentral scotoma was observed along with multiple evanescent white dot syndrome1).
Clinical findings
Section titled “Clinical findings”On fundus examination, it is seen as a raised yellow to yellow-white subretinal lesion. The lesions are often located behind the equator near the optic disc, and are about one disc diameter in size. The findings differ between active and inactive lesions.
Active
Dull yellow and poorly demarcated: the outline is less clear than in inactive lesions.
Localized subretinal fluid: it may be accompanied by yellow intraretinal exudation, retinal vessel dilation, and localized retinal hemorrhage1)2).
Age-related differences in appearance have also been reported. In younger people, nodular or volcano-like protruding lesions are more common, while in older people dome-shaped lesions are typical. Persistent nodular or volcano-like lesions are more likely to cause fluid accumulation and atrophy of the retinal pigment epithelium and retina due to chronic mechanical pressure1).
Q
Does finding a focal scleral nodule affect vision?
A
Most cases are asymptomatic, and the direct effect on vision is limited. Even when symptoms are present, floaters and blurred vision are the main ones, and vision loss is rare. For details, see the section Main symptoms and clinical findings.
3. Causes and risk factors
Section titled “3. Causes and risk factors”The cause of focal scleral nodule is unknown. Several hypotheses are proposed below, but there are no established risk factors.
- Possible congenital origin: Because there are cases that begin in young people, it may be a congenital condition that develops before birth.
- Infection-related theory (older theory): An association with Coxsackie virus and Bartonella infection was suggested, but recent literature is negative. It is possible that different diseases were mixed together1).
- Non-inflammatory scleral lesion: In the study by Fung et al. (2020), there were no signs of active inflammation (choroidal thickening, leakage on fluorescein angiography, vitreitis, or systemic inflammatory findings), and it was concluded to be non-inflammatory1). Duignan et al. (2021) also supported the same conclusion1).
- Possible inflammatory component: Feng et al. (2021) described an “inflammatory granulomatous reaction” in active lesions, so an inflammatory component may still be present in active lesions2). No significant association with systemic inflammatory disease has been found.
4. Diagnosis and testing
Section titled “4. Diagnosis and testing”Diagnosis is made by combining the clinical examination with multimodal imaging. Confirmation of a scleral origin with optical coherence tomography is the most important step.
The findings for each examination method are shown below.
| Examination method | Characteristic findings |
|---|---|
| Enhanced depth imaging optical coherence tomography / swept-source optical coherence tomography | Homogeneous hyperreflective intrascleral nodule, choroidal compression and thinning |
| Optical coherence tomography angiography | Avascular, choroidal flow deficit |
| Fundus autofluorescence | Hyperautofluorescence |
| B-mode ultrasonography | Acoustically solid, no calcification |
| Fluorescein angiography | Early hypofluorescence, late scleral staining |
The details of each examination are shown below.
- Enhanced depth imaging optical coherence tomography / swept-source optical coherence tomography (most important): A homogeneous, highly reflective nodular mass is seen within the sclera, with compression and thinning of the overlying choroid toward Bruch’s membrane 1)3). Swept-source optical coherence tomography can visualize the posterior margin 3). This is the main point that distinguishes it from choroidal lesions.
- Optical coherence tomography angiography (OCTA): The lesion is avascular and reflects choroidal nonperfusion (choroidal blood flow deficit) due to mechanical compression 1)3).
- Fundus autofluorescence: Most lesions show hyperautofluorescence. This is thought to be because thinning of the choroid exposes the scleral autofluorescence 3).
- B-mode ultrasonography: It appears as an acoustically solid lesion 2)3). The absence of calcification with high echogenicity is a distinguishing point from sclerochoroidal calcification.
Differential diagnosis
Section titled “Differential diagnosis”Differentiation from the following diseases is necessary. There is a risk of misdiagnosis and overtreatment; before clinical descriptions were established, it was sometimes mistaken for amelanotic melanoma, metastasis, osteoma, or retinoblastoma, leading to unnecessary treatment 1).
- Malignant tumors: Amelanotic choroidal melanoma, choroidal metastasis, choroidal lymphoma, retinoblastoma
- Benign tumors: Astrocytic hamartoma, choroidal nevus, choroidal osteoma
- Inflammatory diseases: Choroidal granuloma, white dot syndromes, sarcoidosis, ocular tuberculosis, ocular syphilis, fungal chorioretinitis
- Degenerative: Sclerochoroidal calcification — it is located more peripherally than a focal scleral nodule, has an irregular shape, and shows high echogenicity on B-mode ultrasonography
Systemic evaluation should exclude infectious diseases (syphilis, tuberculosis, Lyme disease, Bartonella, Toxocara, Toxoplasma) and inflammatory diseases (sarcoidosis, granulomatosis with polyangiitis) 1)2).
Q
Can a focal scleral nodule be mistaken for a malignant tumor?
A
It may be misdiagnosed as amelanotic choroidal melanoma, choroidal metastasis, choroidal osteoma, or retinoblastoma. Confirming a scleral origin with optical coherence tomography is most important, and systemic evaluation to rule out malignant disease is essential.
5. Standard treatment
Section titled “5. Standard treatment”Most focal scleral nodules are benign conditions that do not require treatment, and their functional impact is limited. The most important point in management is to accurately rule out malignant lesions with a similar appearance, such as amelanotic choroidal melanoma and choroidal metastasis.
Inactive lesion
Observation only: Regular monitoring is performed. No active intervention is needed.
Active lesion
Careful observation is also an option: In one 18-year-old male case, the lesion became inactive over 6 weeks without treatment, with resolution of subretinal fluid and appearance of an orange halo2).
Systemic steroids: They have been suggested as a trial, but there is little evidence of effectiveness.
In a retrospective study of 60 cases by Shields et al., the course during follow-up from 6 months to 25 years (mean 24 months) was stable in 60%, improved in 37%, and recurrent in 3%2). However, 27% had received prior treatment, and no stratification was made between active and inactive lesions.
In a rare case complicated by multifocal transient white dot syndrome, a regimen of intravenous methylprednisolone 80 mg for 3 days followed by a tapering oral prednisone dose of 40 mg was tried. At 11 weeks, best-corrected visual acuity recovered to 20/20 and the findings of multifocal transient white dot syndrome also resolved, but it is difficult to distinguish this from spontaneous improvement1).
Q
If a focal scleral nodule is diagnosed, is surgery necessary?
A
A focal scleral nodule is a benign condition and, in most cases, is managed with observation alone. Even active lesions have been reported to become inactive without treatment, and there is no indication for surgery. If the distinction from malignant disease has already been made, no invasive procedure is needed.
6. Pathophysiology and detailed mechanism of onset
Section titled “6. Pathophysiology and detailed mechanism of onset”The anatomical origin of a focal scleral nodule has been confirmed to be within the sclera by enhanced-depth imaging optical coherence tomography and swept-source optical coherence tomography. It was previously thought to be choroiditis, but it was later found that choroidal involvement was secondary thinning due to compression3).
The sequence of changes caused by mechanical compression from the lesion is as follows.
- Choroidal nonperfusion: The intrascleral nodule compresses the choroid, and this can be confirmed as a choroidal flow void on optical coherence tomography angiography1).
- Retinal pigment epithelium pump dysfunction: Choroidal nonperfusion impairs retinal pigment epithelium function, and subretinal fluid appears in some cases.
- Yellow-white appearance of the fundus: This is because the overlying choroid becomes thin or disappears, allowing the scleral lesion to be seen through it.
- Cause of the orange halo: It is thought to reflect partial thinning of the choroid around the lesion1).
Regarding the mechanism of secondary onset of multiple evanescent white dot syndrome (MEWDS), Sawut et al. (2025) proposed the hypothesis that retinal antigen is exposed by retinal pigment epithelium damage at the apex of a focal scleral nodule, triggering an immune response that leads to a MEWDS-like reaction1). This is consistent with prior reports that exposure of retinal antigen due to retinal pigment epithelium destruction is the underlying mechanism of MEWDS.
Histopathologically, it has not been fully clarified. Feng et al. (2021) described it as an inflammatory granulomatous reaction2), and further investigation is needed.
7. Latest Research and Future Outlook (Reports at the Research Stage)
Section titled “7. Latest Research and Future Outlook (Reports at the Research Stage)”The disease concept of focal scleral nodule has rapidly expanded in recent years, and the following findings are being accumulated.
Sawut et al. (2025) reported the world’s first case of multiple evanescent white dot syndrome secondary to focal scleral nodule1). They suggested that retinal pigment epithelium damage caused by focal scleral nodule may trigger the onset of multiple evanescent white dot syndrome, showing that the complication spectrum of focal scleral nodule is broader.
The main reports in recent years are shown below.
| Author and year | Findings |
|---|---|
| Fung & Li (2024) | Reported growth of focal scleral nodule during follow-up1) |
| Park (2023) | Reported a bifocal focal scleral nodule, suggesting a broader spectrum1) |
| Yamashita et al. (2022) | Reported laser speckle flowgraphy findings1) |
| Stephenson et al. (2024) | Reported multimodal imaging and PD-OCT analysis1) |
In long-term follow-up, most focal scleral nodule lesions remain stable, but some cases of enlargement or regression to focal choroidal excavation have also been reported1). Regarding the naming debate, “focal scleral nodule” (Fung 2020) and “idiopathic scleroma” (Duignan 2021) are competing terms, but at present focal scleral nodule (FSN) is widely used1).
8. References
Section titled “8. References”- Sawut A, Meng Y, Lhamo T, Xiao D, Su Y, Chen C.. Multiple evanescent white dot syndrome associated with focal scleral nodule: a case report and literature review. BMC Ophthalmol. 2025;25(1):413. doi:10.1186/s12886-025-04231-4. PMID:40671005; PMCID:PMC12265223.
- Feng Y, Conrady CD, Demirci H.. The evolution of an active solitary idiopathic choroiditis (focal scleral nodule): a case report of the natural course and a review of the literature. BMC Ophthalmol. 2021;21(1):130. doi:10.1186/s12886-021-01888-5. PMID:33750335; PMCID:PMC7942170.
- Asensio-Sánchez VM, Pacheco-Carllirgos GE, Valentín-Bravo FJ.. Multimodal Imaging Features of Focal Scleral Nodule. Int Med Case Rep J. 2021;14:255-259. doi:10.2147/imcrj.s301633. PMID:33907475; PMCID:PMC8071086.
- Gao J et al. Growth of a Focal Scleral Nodule. Retinal Cases Brief Rep. 2024. PMID: 37027817