Prevalence and clinical characteristics of ocular sarcoidosis among non-infectious uveitis in a Chinese tertiary ophthalmic center: a retrospective observational study

Abstract

Background

The prevalence of ocular sarcoidosis (OS) varies across Asia and the application of the most recent revised diagnostic criteria has not yet been fully adopted. Thus, the prevalence of OS within the Chinese population remains uncertain. We investigate the prevalence of OS among non-infectious uveitis in China, with the Revised criteria of International Workshop on OS.

Methods

In this study, we retrospectively reviewed the medical records of 406 patients who had undergone routine computed tomography scans between May 2019 and June 2023. The diagnosis of OS was made according to the Revised criteria of International Workshop on Ocular Sarcoidosis (IWOS). We further reviewed the clinical characteristics of four patients, including age, gender, anatomical type of uveitis, ocular manifestations, ocular examinations, visual acuity, and complications.

Results

Out of 254 patients with noninfectious uveitis who completed computed tomography, 138 (54.3%) were men, and 116 (45.6%) were women, with a mean age of 38.9 years (ranging from 6 to 77 years). Among the 254 patients with non-infectious uveitis, OS accounted for 1.57% of the cases, however, Behcet’s disease (14.5%) was the predominant etiology, followed by Vogt-Koyanagi-Harada disease (12.9%), retinal vasculitis (1.1%), multifocal choroiditis (1.1%), sympathetic ophthalmia (1.1%), punctate inner choroidopathy (0.7%), and acute posterior multifocal placoid pigment epitheliopathy (0.3%). The study revealed that 3 patients were diagnosed with definite OS, and 1 had presumed OS. Among 406 patients who underwent computed tomography, 0.98% (4/406) of patients met the Revised criteria of IWOS, 1.37% (4/290) of patients with uveitis, and 1.57% (4/254) of patients among non-infectious uveitis.

Conclusions

This study determined the prevalence of OS among non-infectious uveitis in China, and described the clinical characteristics of four individuals.

Background

Sarcoidosis is a systemic multisystem inflammatory disorder characterized by the presence of non-caseating epithelioid granulomas, commonly affecting the pulmonary system and other organs including the eyes, skin, liver, spleen, and lymph nodes [1]. Sarcoidosis affects people of all racial and ethnic groups and can occur at all ages. The patterns of sarcoidosis vary substantially across the world and present regional features, possibly due to different environmental and genetic factors. The incidence of sarcoidosis is highest in Scandinavian countries (11–24 cases per 100,000 individuals per year) [2] and African Americans (18–71 cases per 100,000 individuals per year) [3], whereas Asian countries exhibit the lowest rates (1 case per 100,000 individuals per year) [4].

Ocular manifestations occur in 41% of sarcoidosis patients, and uveitis is the most frequent form, potentially affecting up to 23% of patients [5, 6]. Within Asia, the prevalence of ocular sarcoidosis (OS) differs geographically. The prevalence of OS in the Indian population is 3.8%, with panuveitis comprising 9.4% of OS cases [7]. An etiological survey in Japan revealed that OS accounts for the majority of intraocular inflammatory diseases at 10.6%, followed by Vogt–Koyanagi–Harada disease [8]. In Thailand, the prevalence of OS has been estimated to be 2% [9]. This pattern is very different from that seen in European and US populations. However, the implementation of computed tomography (CT) screening among patients with NIU remains incomplete, and the application of the most recent revised diagnostic criteria has not yet been fully adopted. Thus, the prevalence of OS within the Chinese population remains uncertain, and it is unclear whether OS continues to be underdiagnosed in Asia.

OS can manifest independently without obvious systemic involvement and could be the primary site of the disease without significant clinical disease elsewhere. In a recent study of sarcoid uveitis, it was observed that ophthalmological features were the initial presenting symptoms in 78.8% of OS, with the median time to the development of symptomatic systemic sarcoidosis was 12 months [10]. Therefore, a high level of suspicion should be warranted when uveitis symptoms appear in patients who have not been diagnosed with sarcoidosis.

According to the revised criteria of International Workshop on Ocular Sarcoidosis (IWOS) [11], bilateral hilar lymphadenopathy (BHL) identified through standard chest X-ray and CT scan is now considered a single diagnostic outcome, and systemic investigations for suspected OS have been advised to eight distinct findings. Additionally, the diagnostic criteria for possible OS have been deleted and categorized into three categories. Accordingly, there is no research completing routine CT examinations in non-infectious uveitis (NIU) patients to diagnose OS in China on the basis of the latest diagnostic criteria, and auxiliary examinations such as performing a biopsy have not been routinely and widely carried out.

This retrospective study aimed to determine the prevalence of OS in China according to the latest diagnostic criteria. We explore the possibility of 254 consecutive patients completing CT with NIU and describe the clinical characteristics of four Chinese patients diagnosed with OS.

Methods

In this study, we retrospectively reviewed the medical records of 406 patients. These patients had undergone routine CT scans and were consecutively referred to the uveitis department of the Zhongshan Ophthalmic Center between May 2019 and June 2023. This study was performed according to the principles of the Helsinki Declaration and was approved by the ethics committee of the Zhongshan Ophthalmic Center.

The following were the inclusion criteria:

1. Ocular manifestations present with NIU, according to the Standardization of Uveitis Nomenclature Working Group (SUN) [12].

2. All patients with uveitis underwent a comprehensive screening protocol, which included a chest computed tomography scan and various laboratory tests, including routine blood tests, infection panel four tests, hepatic and renal function tests, biochemical blood tests, urinalysis, and interferon-gamma release assays (IGRA), primarily to exclude the presence of infections. Initial patients need to undergo CT scans to identify sarcoidosis, detect potential or old tuberculosis infections, and potential malignancies, and informed consent is obtained from all patients before the examination. This diagnostic workup was performed under both our standard clinical practice and research protocol.

3. At least one or more ocular examinations including fundus photography (FP) (Zeiss FF450 Plus; Carl Zeiss, Inc., Jena, Germany), anterior segment photography (BX900; Haag-Streit AG, Ko¨niz, Switzerland), and fluorescein angiography (FA) (HRA Spectralis, Heidelberg Engineering, Heidelberg, Germany), were performed.

The exclusion criteria were as follows:

1. Patients were diagnosed with infectious uveitis, especially tuberculosis uveitis, on the basis of the SUN.

In the SUN database, 6.1% of patients with tuberculosis uveitis had BHL on chest imaging, of whom 76% were from Asian countries, thus BHL, and a positive tuberculin skin test or IGRA cannot be solely reliable. Given the above, patients with positive IGRA and highly suspected infection on CT were excluded from our study [13]. The selection process for uveitis patients is shown in Fig. 1.

Fig. 1.

Flowchart depicting the selection of uveitis patients

The classification of uveitis was based on the criteria of the SUN Working Group [12]. The diagnosis of OS was made according to the Revised criteria of IWOS [11]. We further reviewed the clinical characteristics of four patients, including age, gender, anatomical type of uveitis, ocular manifestations, ocular examinations, visual acuity, and complications.

Results

A total of 290 patients with uveitis were eligible for the study among 406 consecutive case records between May 2019 and April 2023. Among 290 uveitis patients who completed routine CT, 36 (12.4%) patients were excluded from the study primarily because of infectious factors, such as viral infections, syphilis, and notably underlying tuberculosis. As a result, 254 patients were diagnosed with NIU.

Among the 254 patients with NIU included in the study, 138 (54.3%) were men, and 116 (45.6%) were women, with a mean age of 38.9 years (ranging from 6 to 77 years). Of 254 patients, Behcet’s disease (BD) (14.5%) was the most predominant etiology, followed by Vogt-Koyanagi-Harada disease (12.9%), OS (1.57%), retinal vasculitis (1.1%), multifocal choroiditis (1.1%), sympathetic ophthalmia (1.1%), punctate inner choroidopathy (0.7%), and acute posterior multifocal placoid pigment epitheliopathy (0.3%). A pie chart of the various uveitis types is displayed in Table 2. Notably, three characteristic CT signs were identified in 254 patients. Specifically, BHL was found in 4 patients (1.57%), unilateral hilar lymphadenopathy in 1 patient (0.3%), and mediastinal lymphadenopathy in 14 patients (5.5%). Additionally, six non-characteristic signs were observed, including ground-glass opacity in 31 patients (12.2%), linear opacities in 103 patients (40.5%), nodule opacities in 100 patients (39.3%), lymph node calcification in 15 patients (5.9%), pulmonary calcified lesions in 37 patients (14.5%), and pleural thickening in 10 patients (3.9%). The main demographic and clinical characteristics of the study patients are shown in Table 1. Further analysis revealed that 0.98% (4/406) patients met the criteria of IWOS in a total of 406 patients, 1.37% (4/290) of patients with uveitis, and 1.57% (4/254) of patients with NIU. The specific proportions of sarcoidosis are illustrated in Fig. 2. To elaborate, 3 (1.18%) patients with uveitis were diagnosed with definite OS confirmed through lung biopsy in general hospitals, and 1 (0.39%) patient had presumed OS based on clinical manifestations. All four patients were evaluated by at least one pulmonologist, and tuberculosis was ruled out. The detailed clinical characteristics of these four patients are depicted in Table 2.

Table 2.

Clinical characteristics of four patients with OS

	Patient 1	Patient 2	Patient 3	Patient 4
Gender	Male	Female	Male	Male
Age of onset (years)	25	25	24	20
Anatomical type	Panuveitis	Panuveitis	Panuveitis	Panuveitis
Clinical characteristics at the presentation  Presenting symptoms	Blurred vision and redness	Blurred vision	Blurred vision, redness, and eye pain	Blurred vision, redness, and eye pain
Laterality of ocular involvement	Bilateral	Bilateral	Bilateral	Bilateral
Ocular manifestations (OD; OS)
Keratic precipitates	1+; 1+	2+; 1+	3+; 3+	4+; 3+
Anterior chamber cells	1+; 1+	1+; 1+	3+; 3+	2+; 2+
Anterior chamber flare	-; -	1+; 1+	2+; 2+	2+; 2+
Posterior synechiae	-; -	+; -	-; -	-; -
Iris nodules	-; -	-; -	-; -	1+; 1+
Vitritis	1+; 1+	-; -	1+; 1+	1+; 1+
Ocular examinations
FP	Optic disc edema	Optic disc edema	-	Retinitis
OCT	-	Macular edema	Optic disc edema	-
FA	Optic disc edema	-	Optic disc edema, retinitis, and vasculitis	-
IWOS criteria	Definite	Definite	Presumed	Definite
Complications	Cataract	Cataract	Cataract	Cataract
Therapy
Corticosteroids	+	+	+	+
Immunosuppressants	+	+	+	+
Biological agents	+	+	+	-
Outcome	Better	Better	Better	Worse

FP: fundus photography; OCT: Optical coherence tomography; FA: Fluorescein angiography

OD: right eye; OS: left eye

Table 1.

Characteristics of 254 patients with non-infectious uveitis

Characteristics	Value
Gender, No.(%)
Male	138 (54.3)
Female	116 (45.6)
Etiology, No.(%)
Vogt-Koyanagi-Harada disease	33 (12.9)
Behçet’s disease	37 (14.5)
OS	4 (1.57)
Definite OS	3 (1.1)
Presumed OS	1 (0.3)
Multifocal choroiditis	3 (1.1)
Punctate inner choroidopathy	2 (0.7)
Acute posterior multifocal	1 (0.3)
Placoid pigment epitheliopathy
Sympathetic ophthalmia	3 (1.1)
Retinal vasculitis	3 (1.1)
Computed tomography signs, No.(%)
Bilateral hilar lymphadenopathy	4 (1.5)
Unilateral hilar lymphadenopathy	1 (0.3)
Mediastinal lymphadenopathy	14 (5.5)
Ground-glass opacity	31 (12.2)
Linear opacities	103 (40.5)
Nodule opacities	100 (39.3)
Lymph node calcification	15 (5.9)
Pulmonary calcified lesions	37 (14.5)
Pleural thickening	10 (3.93)

Fig. 2.

Pie chart of uveitis-type distributions

The first patient was a 25-year-old male who presented with blurred vision and redness in both eyes at the first visit. The patient had no prior history of systemic sarcoidosis, and the diagnosis was initiated from ocular findings. Moreover, he exhibited no systemic symptoms related to other organs, and laboratory tests did not reveal any clinically significant abnormalities. The initial visual acuity (Snellen) was 0.63 in the right eye and 0.4 in the left eye, and the intraocular pressure was 11 mmHg in both eyes. Slit-lamp examination revealed mutton-fat keratic precipitates of 1+, anterior chamber cells of 1+, and vitritis of 1 + in both eyes. Optic disc edema was observed in both eyes on FP and FA, which also indicated diffuse retinitis and neovascularization in the peripheral retina. Despite negative laboratory test results, NIU was suspected. Nonetheless, a CT scan showing BHL and mediastinal lymphadenopathy prompted further investigation (Fig. 3). To identify the etiology, we sincerely recommended the patient undergo a lung biopsy at a general hospital. With multiple efforts, a lung biopsy was performed and sarcoidosis was confirmed by a respiratory expert. According to the IWOS criteria, this patient matched the demand for definite OS. The patient was initially treated with a combination of oral corticosteroids and immunosuppressants, including methotrexate and cyclosporine. However, due to persistent inflammation and an incomplete response to the initial therapy, adalimumab was introduced after three months. Subsequently, a comprehensive anti-inflammatory regimen was initiated, which included oral corticosteroids, immunosuppressants such as methotrexate and cyclosporine, and adalimumab. The patient was followed up for one year. There was a significant improvement in visual acuity, with the right eye improving to 0.8 and the left eye to 0.63. Slit-lamp examination and FA (Fig. 4) indicated the resolution of inflammation in both eyes. No significant extraocular involvement was reported.

Fig. 3.

Coronal CT scans showing BHL in OS (arrows)

Fig. 4.

The clinical course of patient one. (A) Fluorescein angiography of patient one revealed diffuse retinal vasculitis and macular edema. (B) At one year, macular edema resolved, with improved perfusion of the venules and capillary plexus

The second patient was a 25-year-old female who presented with blurred vision in both eyes and had a known diagnosis of systemic sarcoidosis for two years prior to the onset of ocular symptoms. Additionally, she exhibited a cough but lacked systemic symptoms associated with other organs. Laboratory tests revealed no clinically significant abnormalities. Her visual acuity (Snellen) was FC/20 cm in the right eye and 0.63 in the left eye, and the intraocular pressure was 15 mmHg in the right eye and 13 mmHg in the left eye. The slit-lamp examination revealed mutton-fat keratic precipitates with 2 + in the right eye and 1 + in the left eye. Both eyes exhibited 1 + anterior chamber cells and 1 + anterior chamber flares. Additionally, posterior synechiae were observed in the right eye. FP displayed optic disc edema and optical coherence tomography (OCT) showed macular edema in the right eye. Excluded infectious factors, the presumed OS was determined based on the IWOS criteria. The patient received anti-inflammatory therapy for three months, starting with oral corticosteroids and methotrexate. Given the partial response and continued inflammation, adalimumab was initiated after the initial one-month course. The patient was followed up for three months, and visual acuity improved to 0.025 in the right eye and 0.8 in the left eye. Follow-up slit-lamp examination showed no anterior chamber cells in either eye. The patient exhibited mild cough but no other significant extraocular involvement.

The third patient, a 24-year-old man presenting with recurrent blurred vision, redness, and eye pain in both eyes, had been diagnosed with uveitis 7 months before being reported. The patient had no prior history of systemic sarcoidosis, and the diagnosis was initiated from ocular findings. Moreover, he exhibited no systemic symptoms related to other organs, and laboratory tests disclosed no clinically significant abnormalities. The initial visual acuity (Snellen) was 0.4 in the right eye and 0.2 in the left eye, and the intraocular pressure was 10 mmHg in the right eye and 9 mmHg in the left eye. Slit-lamp examination revealed significant inflammation in both eyes, characterized by 3 + mutton-fat keratic precipitates, 3 + anterior chamber cells, 2 + anterior chamber flares, and 1 + vitritis. FA and OCT depicted bilateral optic disc edema, retinitis, and vasculitis. A CT scan also indicated BHL. According to IWOS criteria, the patient conformed to the demand for presumed OS. Anti-inflammatory therapy was initiated with oral corticosteroids, methotrexate, and cyclosporine. Due to the severity of inflammation and the need for more robust control, adalimumab was introduced after one month of initial therapy. The patient was followed up for two months. Visual acuity improved to 0.8 in the right eye and 0.4 in the left eye. Subsequent slit-lamp examination revealed anterior chamber cells 0.5 + in both eyes. No significant extraocular involvement was reported.

The fourth patient was a 20-year-old male who had a prior diagnosis of systemic sarcoidosis and presented with recurrent blurred vision, redness, and intermittent eye pain in both eyes over a two-year period. The patient experienced cough and chest tightness but had no other systemic symptoms related to other organs. Laboratory tests did not reveal any clinically significant abnormalities. The patient’s initial visual acuity (Snellen) was hand motion/ 30 cm and 0.25 in the right and left eyes respectively, and the intraocular pressure was 9 mmHg in both eyes. Slit-lamp examination revealed mutton-fat keratic precipitates, with 4 + in the right eye and 3 + in the left eye, as well as 2 + anterior chamber cells and anterior chamber flares in both eyes. Vitritis was graded as 1 + in both eyes. Additionally, iris nodules consistent with Busacca nodules were observed. The FP exhibited severe vitreous opacity in the right eye and milky white lesions in the peripheral retina of the left eye. Based on the IWOS criteria, the patient was diagnosed with definite OS. He was treated with a combination of oral corticosteroids and immunosuppressants, including methotrexate and cyclosporine. Due to economic constraints, adalimumab was not prescribed, and the patient continued on conventional therapy. The patient was followed up for six months, however, visual acuity did not fully recover in either eye. The patient experienced cough and chest tightness but no other significant extraocular involvement at the last follow-up.

Discussion

Sarcoidosis is a multisystemic chronic inflammatory disorder of unknown cause, and the proportion of patients who show ocular involvement may differ according to the population under study. To our knowledge, the current study is the first to determine the prevalence of OS via routine CT scans among patients with NIU in China. Our research showed that, among 254 patients with NIU, 138 (54.3%) were men and 116 (45.6%) were women with a mean age of 38.9 years. In a study with biopsy-proven systemic sarcoidosis [14], two peaks of incidence were reported, the first in 20–30 years, and the second in those aged 50–60 years. This finding is consistent with that of a previous study in which the mean age of OS patients was 23.5 year. Our data revealed a preponderance of panuveitis as the anatomical type of OS, similar to the findings of a Japanese population study [15]. However, a previous study found that anterior uveitis was the most common anatomical type [16]. The prevalence of OS is 1.57% in China. To our knowledge, our study is similar to those reported in other Asian countries [9, 17]. In contrast, sarcoidosis is a relatively common cause of uveitis in Japan distinguished from the rest in Asia, accounting for 10–13.3% of uveitis cases, followed by Vogt-Koyanagi-Harada disease [18–20].

Diagnosing definite OS can be challenging owing to the invasive nature of biopsy, which is often not feasible. In the previous report, ocular manifestations were the first indication of the disease [21]. Similarly, our study’s third patient presented with characteristic signs of granulomatous uveitis, including binocular mutton-fat keratic precipitates of 3+, anterior chamber cells of 3+, and vitritis of 1+. FA and OCT depicted bilateral optic disc edema, retinitis, and vasculitis, whereas systemic symptoms did not present. Although there has been adequate evidence to support the diagnosis of OS, the patient refused biopsy. To date, conjunctival and lacrimal gland biopsies have been used to diagnose OS, but their effectiveness remains limited, with positive rates ranging from 40.4 to 43% [22, 23]. As an alternative, CT scans have proven to be a valuable diagnostic tool in the diagnosis of OS. Febvay et al.’s study of 83 biopsy-proven sarcoid uveitis cases found that 91.2% of patients had abnormal CT findings suggestive of sarcoidosis [24]. Additionally, Babu et al. demonstrated that high-resolution CT scans can differentiate OS from ocular tuberculosis based on the presence of hilar lymphadenopathy and fissural nodules [25]. Chest CT provides detailed information for OS and has become a valuable diagnostic tool in our daily clinical practice. In light of these findings, we recommend the use of CT scans in the diagnostic workup for patients with granulomatous uveitis to screen not only for sarcoidosis but also for tuberculosis, and prevent early systemic complications.

The diagnosis of sarcoidosis can be challenging due to the variability of radiographic patterns, including atypical adenopathy, which can lead to misleading diagnoses. Although BHL has the highest predictive value and odds ratio, which confirms its clinical value in diagnosing sarcoidosis [26], it is not always present. Freundlich et al. reported that up to 17% of patients had atypical adenopathy, characterized by nodal involvement without apparent lymphadenopathy in 25% of 300 proven sarcoidosis patients [27]. Furthermore, atypical radiographic findings, such as mediastinal adenopathy alone or in combination with unilateral hilar adenopathy, can be present in up to 21% of patients with pulmonary sarcoidosis [28]. Borciuch et al. reported that 13.8% of patients with proven sarcoidosis had mediastinal lymphadenopathy without hilar involvement on chest CT, highlighting the importance of considering mediastinal lymphadenopathy as a diagnostic criterion for sarcoidosis [29]. In our study, 6.2% of patients had mediastinal lymphadenopathy, suggesting that this finding should not be overlooked in the diagnosis of sarcoidosis. Although CT is not a mandatory examination for the diagnosis of uveitis, it serves as a critical diagnostic modality for identifying sarcoidosis, detecting latent or old tuberculosis infections, and excluding malignancies. These diagnostic steps are essential components in the management of uveitis. CT is particularly valuable due to its high specificity in detecting these conditions. In the long term, early identification of sarcoidosis, prevention of potential infection activity, and prevention of complications from biological agents through CT can significantly impact patient management and outcomes, potentially reducing long-term complications and overall healthcare costs. However, it should still be noted that before conducting a CT scan, the patient’s cumulative radiation exposure and pregnancy status in women should be inquired about. Genetic testing may serve as a potentially valuable ancillary diagnostic tool, such as the CCL24, C1orf141-IL23R, and HLA-DRB1 alleles [30–33]. However, its associations exhibit racial-specific differences and have not yet been validated through standardized clinical trials. The lack of routine biopsy and systemic investigations, such as serum angiotensin-converting enzyme, serum lysozyme, and bronchoalveolar lavage in China, may have led to an underestimation of the proportion of OS in our study. In light of these findings, this underscores the need for a comprehensive diagnostic approach, including radiographic and clinical evaluations, as well as laboratory tests, to ensure accurate diagnosis and management of sarcoidosis.

In recent years, the effectiveness of different biological agents for NIU has been reported [34]. Riancho-Zarrabeitia L et al. demonstrated the efficacy and safety of anti-tumor necrosis factor-α therapy in patients with sarcoid uveitis, leading to a significant reduction in corticosteroid use [35]. In a prospective trial, Suhler EB found that adalimumab was safe and effective in 68% of refractory uveitis patients, of whom 19.3% of OS patients exhibited favorable visual outcomes [36]. Consistent with these findings, our cases have shown a favorable prognosis with biological agent treatment in the first, second, and third patients. However, due to economic restraints, patient four was treated with conventional therapy without receiving adalimumab and experienced an unfavorable visual outcome. Currently, IWOS has reached a consensus to include biological agents in the treatment considerations for OS, with adalimumab being the specific biological agent discussed [37].

Our study has several limitations that should be acknowledged. First, the study was conducted in a single ophthalmic specialist hospital, which may have introduced selection bias due to the hospital’s location and reputation. This may not be representative of the entire country, given the vast geographic expanse and uneven development of China. As a result, our findings may not be generalizable to other regions or populations. Further multicenter studies are needed to better understand the national prevalence of OS in China. Another limitation is the small sample size, particularly with regard to elderly patients with OS. During the three-year study period, only four young patients were diagnosed with OS, which limited our ability to collect clinical data from elderly patients. This highlights the need for multi-center collaborations to expand the sample size and conduct large-scale surveys to clarify the clinical characteristics of OS in China. In addition, a further description of extra-ocular manifestations is beyond the scope of this study due to the limitation of specialty. A comprehensive understanding of sarcoidosis requires a multidisciplinary approach that incorporates data from various specialties. Nevertheless, an attempt has been made to outline the characteristics of OS patients in China. Despite these limitations, our study provides a foundation for further investigations in the Asian population.

Conclusions

In conclusion, our study provides valuable insights into the prevalence of OS among NIU patients in the Chinese tertiary ophthalmic Center, highlighting the importance of vigilant detection and surveillance of associated systemic diseases among patients with NIU. Both ophthalmologists and general clinicians must be aware of the potential for OS among NIU, and take steps to identify and manage it accordingly. Moreover, interdisciplinary cooperation is of paramount importance for patients with OS. We recommend that patients suspected of having sarcoidosis undergo chest CT scans and be referred to the respiratory department for further evaluation and management.

Abbreviations

OS

Ocular sarcoidosis

CT

Computed tomography

IWOS

International Workshop on Ocular Sarcoidosis

BHL

Bilateral hilar lymphadenopathy

NIU

Non-infectious uveitis

SUN

Standardization of Uveitis Nomenclature

IGRA

Interferon-gamma release assays

FP

Fundus photography

FA

Fluorescein angiography

OCT

Optical coherence tomography

BD

Behcet’s disease

GWAS

Genome-wide association study

Author contributions

Wenru Su conceived and designed the study. Daquan He, Xuening Peng, and Jianjie Lv collected the patient’s data. Daquan He, and Tianyu Tao reviewed the patient data. Daquan He analyzed the data and provided interpretation. Daquan He, and Tianyu Tao wrote the main manuscript. Wenru Su revised the manuscript. All authors read and approved the final manuscript.

Funding

This study was supported by the National Outstanding Youth Science Fund Project of China (82122016).

Data availability

The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This was a retrospective study conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of Zhongshan Ophthalmic Center, which waived the written informed consent because of the study’s retrospective design.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.