Cell atlas of the human ocular anterior segment: Tissue-specific and shared cell types.

The anterior segment of the eye consists of the cornea, iris, ciliary body, crystalline lens, and aqueous humor outflow pathways. Together, these tissues are essential for the proper functioning of the eye. Disorders of vision have been ascribed to defects in all of them; some disorders, including glaucoma and cataract, are among the most prevalent causes of blindness in the world. To characterize the cell types that compose these tissues, we generated an anterior segment cell atlas of the human eye using high-throughput single-nucleus RNA sequencing (snRNAseq). We profiled 195,248 nuclei from nondiseased anterior segment tissues of six human donors, identifying >60 cell types. Many of these cell types were discrete, whereas others, especially in the lens and cornea, formed continua corresponding to known developmental transitions that persist in adulthood. Having profiled each tissue separately, we performed an integrated analysis of the entire anterior segment, revealing that some cell types are unique to a single structure, whereas others are shared across tissues. The integrated cell atlas was then used to investigate cell type-specific expression patterns of more than 900 human ocular disease genes identified through either Mendelian inheritance patterns or genome-wide association studies.

Proteomic analysis of Exosomes derived from the Aqueous Humor of Myopia Patients.

Objectives: Myopia is the most common refractive vision disorder. In recent years, several studies have suggested that the alteration of the exosomal protein levels in the aqueous humor (AH) is associated with the development of several eye diseases. Therefore, we aimed to explore the exosomal protein profile of the AH from myopia patients. Methods: Exosomes were isolated from the AH. The quality, concentration, and size distribution of exosomes for each patient were measured using nanoparticle tracking analysis system. Then, the exosomal proteins were purified and digested by trypsin for liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Results: There was no significant difference observed between the myopia and control when comparing the concentration and size distribution of exosomes in the AH for each sample. Based on LC-MS/MS analysis, myopia patients had higher and more complex exosomal peptide content. We found two proteins that were common in AH exosomes and eight proteins that were highly expressed in the myopia group. Conclusions: Our results provide pioneering findings for the exploration of the exosomal protein profile in myopia development. Further studies may provide significant information for the diagnosis, clinical treatment, and prognosis of myopia.

Intraocular leucocyte subpopulations analysis by multiparametric flow cytometry in human uveitis.

PURPOSE: The aim of this study was to describe the cellular infiltrate in aqueous and vitreous samples of patients with uveitis analysed by multiparametric flow cytometry. METHODS: This is a retrospective analysis of aqueous and vitreous samples analysed by flow cytometry for diagnostic purposes, in cases of masquerade syndromes and infectious and non-infectious uveitis. Data collected included demographics, anatomical classification of uveitis, phenotypic diagnosis, anterior chamber cells grading, vitreous haze and time of follow-up since presentation to sample obtained. RESULTS: Thirty-one samples (17 aqueous and 14 vitreous fluids) from 31 patients, 18 men, were analysed. The mean age at the time of sample collection was 60.23±17.03 years. The most frequent anatomical classification was panuveitis (14 of 31). T cells accounted for the main cellular component in the majority of the samples (10 of 13 aqueous samples; 7 of 14 in vitreous samples). CD4:CD8 ratios ranged from 0.21 to 16.3 in the case of aqueous samples and from 0.5 to 9.7 in the case of vitreous samples. DISCUSSION: Flow cytometry analysis of aqueous and vitreous samples from patients with uveitis could provide insight into the pathogenesis of human uveitis and help develop accurate animal models which better mimic human disease.

Aqueous Humor Outflow Requires Active Cellular Metabolism in Mice.

Purpose: Conventional wisdom posits that aqueous humor leaves the eye by passive bulk flow without involving energy-dependent processes. However, recent studies have shown that active processes, such as cell contractility, contribute to outflow regulation. Here, we examine whether inhibiting cellular metabolism affects outflow facility in mice. Methods: We measured outflow facility in paired enucleated eyes from C57BL/6J mice using iPerfusion. We had three Experimental Sets: ES1, perfused at 35°C versus 22°C; ES2, perfused with metabolic inhibitors versus vehicle at 35°C; and ES3, perfused at 35°C versus 22°C in the presence of metabolic inhibitors. Inhibitors targeted glycolysis and oxidative phosphorylation (2-deoxy-D-glucose, 3PO and sodium azide). We also measured adenosine triphosphate (ATP) levels in separate murine anterior segments treated like ES1 and ES2. Results: Reducing temperature decreased facility by 63% [38%, 78%] (mean [95% confidence interval (CI)], n = 10 pairs; P = 0.002) in ES1 after correcting for changes in viscosity. Metabolic inhibitors reduced facility by 21% [9%, 31%] (n = 9, P = 0.006) in ES2. In the presence of inhibitors, temperature reduction decreased facility by 44% [29%, 56%] (n = 8, P < 0.001) in ES3. Metabolic inhibitors reduced anterior segment adenosine triphosphate (ATP) levels by 90% [83%, 97%] (n = 5, P<<0.001), but reducing temperature did not affect ATP. Conclusions: Inhibiting cellular metabolism decreases outflow facility within minutes. This implies that outflow is not entirely passive, but depends partly on energy-dependent cellular processes, at least in mice. This study also suggests that there is a yet unidentified mechanism, which is strongly temperature-dependent but metabolism-independent, that is necessary for nearly half of normal outflow function in mice.

Detection of feline coronavirus RNA, spike gene mutations, and feline coronavirus antigen in macrophages in aqueous humor of cats in the diagnosis of feline infectious peritonitis.

Uveitis is common in cats, and is often a feature of feline infectious peritonitis (FIP). We evaluated 3 tools for detection of feline coronavirus (FCoV) in aqueous humor: 1) a 7b gene reverse-transcription real-time PCR (7b-RT-rtPCR) assay to detect FCoV RNA, 2) a spike gene mutation RT-rtPCR (S-RT-rtPCR) assay to detect 2 point mutations in the spike gene of FCoV in cats positive by 7b-RT-rtPCR, and 3) immunocytochemistry (ICC) for detection of FCoV antigen in aqueous humor macrophages. We studied 58 cats, including 31 cats with FIP and 27 control cats. FIP was excluded by postmortem examination and negative immunohistochemistry (IHC). Aqueous humor samples obtained postmortem were assessed using 7b-RT-rtPCR in all cats, and positive samples were evaluated with S-RT-rtPCR. ICC evaluation of aqueous humor samples from 36 of the 58 cats was done using an avidin-biotin complex method and monoclonal anti-FCoV IgG 2A. Sensitivity, specificity, and negative and positive predictive values were calculated including 95% CIs. 7b-RT-rtPCR had a specificity of 100.0% (95% CI: 87.2-100.0) and sensitivity of 35.5% (95% CI: 19.2-54.6). Specificity of S-RT-rtPCR could not be determined because there were no FCoV 7b-RT-rtPCR-positive samples in the control group. Sensitivity of S-RT-rtPCR was 12.9% (95% CI 3.6-29.8). Sensitivity and specificity of ICC were 62.5% (95% CI: 40.6-81.2) and 80.0% (95% CI: 44.4-97.5), respectively. The combination of 7b-RT-rtPCR and IHC could be useful in diagnosing FIP; S-RT-rtPCR did not add value; and ICC of aqueous humor samples cannot be recommended for the diagnosis of FIP.

Proliferative Status in the Aqueous Humor of Eyes With Congenital Cataract.

PURPOSE: To measure the concentrations of growth factors in the aqueous humor of patients with congenital cataract and to investigate the biological effects of a selected cytokine (fibroblast growth factor 4 [FGF4]) on cell proliferation, migration, and transformation. METHODS: In the aqueous humor obtained from 55 eyes with congenital cataract and 55 eyes with age-related cataract, 40 growth factors were screened and selected cytokines were confirmed with enzyme-linked immunosorbent assays. After the addition of various concentrations of FGF4 (0, 2.5, 15, or 50 ng/mL) to the incubation medium, cellular functions were evaluated. RESULTS: The concentration of FGF4 was significantly higher in the aqueous humor of patients with congenital cataract than in that of patients with age-related cataract. The human SRA01/04 lens epithelial cell line was treated with FGF4 and the cell proliferation increased significantly both dose- and time-dependently. The wound healing assay and Transwell migration assay revealed a significant increase in the migration capacity of the SRA01/04 cell line treated with 15 or 50 ng/mL of FGF4 compared with that of control cells. The intensity of immunofluorescent staining for α-smooth muscle actin increased significantly in the SRA01/04 cell line when treated with FGF4. Cytoskeletal protein (F-actin) staining showed that changes of cell morphology were induced in primary lens epithelial cells by FGF4. CONCLUSIONS: This study provides a comprehensive profile of growth factors in congenital cataract. FGF4 induced cellular changes, and may have utility as a biomarker to predict the formation of visual axis opacification. [J Pediatr Ophthalmol Strabismus. 2020;57(3):159-168.].

Alterations of aqueous humor Aß levels in Aß-infused and transgenic mouse models of Alzheimer disease.

Alzheimer's disease (AD) is an ageing-related neurodegenerative disease characterized and diagnosed by deposition of insoluble amyloid-ß (Aß) plaques in the brain. The plaque accumulation in the brain directly affects reduced levels of Aß in cerebrospinal fluid (CSF) and blood, as Aß can freely transport the blood-brain barrier, and clinical investigations have suggested these two biofluids as promising samples for in vitro diagnosis. Given that the human eye structurally resembles the brain and Aß accumulation often observed in the ocular region of AD patients, in this study, we examined aqueous humor Aß as another possible surrogate biomarker. First, using the acute Aß-infused AD mouse model by injecting Aß to the CSF in intracerebroventricular region of normal ICR mice, we investigated whether Aß concentration in the aqueous humor in AD models is positively correlated with the concentration in the CSF. Then, we examined the correlation of aqueous humor Aß levels with increased plaque deposition in the brain and reduced Aß levels in both CSF and blood in adult and aged 5XFAD Alzheimer transgenic mice. Collectively, the synthetic Aß injected into CSF immediately migrate to the aqueous humor, however, the age-dependently reducing pattern of Aß levels in CSF and blood was not observed in the aqueous humor.

Reacción en cadena de la polimerasa en fluidos oculares en las formas atípicas de uveítis posterior / Polymerase chain reaction in ocular fluids in atypical forms of posterior uveitis

RESUMEN La toxoplasmosis ocular es la causa de uveítis posterior más frecuente en muchos países. El diagnóstico correcto se basa principalmente en las características clínicas de la enfermedad; pero en las formas de uveítis posterior atípicas se necesita el apoyo del laboratorio para confirmar el diagnóstico y no indicar tratamientos inapropiados. Se resalta el valor de la reacción en cadena de la polimerasa en fluidos oculares en pacientes con títulos serológicos en suero positivos para toxoplasma y presentaciones atípicas de uveítis posterior. Se presenta un caso clínico de una paciente con toxoplasmosis sistémica, confirmada con títulos serológicos en suero positivos, quien concomitó con uveítis posterior bilateral sin características típicas de toxoplasmosis ocular, en la cual la reacción en cadena de la polimerasa de fluidos oculares fue esencial en el diagnóstico. La reacción en cadena de la polimerasa en fluidos oculares constituye una herramienta inequívoca en el diagnóstico correcto de las formas atípicas de uveítis posteriores(AU)

ABSTRACT Ocular toxoplasmosis is the most frequent cause of posterior uveitis in many countries. Correct diagnosis is mainly based on the clinical characteristics of the disease, but in atypical forms of posterior uveitis laboratory support is required to confirm the diagnosis and not indicate inappropriate treatments. Evidence is provided of the usefulness of polymerase chain reaction in ocular fluids from patients with serum serological titers positive for toxoplasma and atypical presentations of posterior uveitis. A clinical case is presented of a female patient with systemic toxoplasmosis confirmed by positive serum serological titers and concomitant bilateral posterior uveitis without typical features of ocular toxoplasmosis, in which polymerase chain reaction in ocular fluids was essential for the diagnosis. Polymerase chain reaction in ocular fluids is an unequivocal tool for the correct diagnosis of atypical forms of posterior uveitis(AU)

Electron Microscopic Evidence of Photoreceptor Outer-segments in the Trabecular Meshwork in a Case of Schwartz-Matsuo Syndrome.

PURPOSE: To describe a case of photoreceptor outer segment glaucoma (Schwartz-Matsuo syndrome) with electron microscopic evidence of photoreceptor outer segments in the trabecular meshwork (TM). DESIGN: This is a clinicopathologic case report. PARTICIPANT: A 48-year-old Filipino man. METHODS: Specimens of aqueous humor and TM in a clinical case of Schwartz-Matsuo syndrome were examined by electron microscopy. MAIN OUTCOME MEASURES: Electron photomicroscopy. RESULTS: Electron microscopy showed evidence of retinal photoreceptor outer-segments in both an aqueous humor and a TM specimen. CONCLUSION: Schwartz-Matsuo syndrome is associated with the presence of photoreceptor outer segments in the TM.

The LRRC8-mediated volume-regulated anion channel is altered in glaucoma.

Regulation of cellular volume is an essential process to balance volume changes during cell proliferation and migration or when intracellular osmolality increases due to transepithelial transport. We previously characterized the key role of volume-regulated anion channels (VRAC) in the modulation of the volume of trabecular meshwork (TM) cells and, in turn, the aqueous humour (AH) outflow from the eye. The balance between the secretion and the drainage of AH determines the intraocular pressure (IOP) that is the major casual risk factor for glaucoma. Glaucoma is an ocular disease that causes irreversible blindness due to the degeneration of retinal ganglion cells. The recent identification of Leucine-Rich Repeat-Containing 8 (LRRC8A-E) proteins as the molecular components of VRAC opens the field to elucidate their function in the physiology of TM and glaucoma. Human TM cells derived from non-glaucomatous donors and from open-angle glaucoma patients were used to determine the expression and the functional activity of LRRC8-mediated channels. Expression levels of LRRC8A-E subunits were decreased in HTM glaucomatous cells compared to normotensive HTM cells. Consequently, the activity of VRAC currents and volume regulation of TM cells were significantly affected. Impaired cell volume regulation will likely contribute to altered aqueous outflow and intraocular pressure.

Cytokines concentrations in aqueous humor of eyes with uveal melanoma.

Uveal melanoma (UM) is the major intraocular malignancy in adults, of which the molecular biology is still unknown. Therefore, this study was designed to determine the aqueous concentrations of angiogenic, inflammatory, and chemotactic cytokines in eyes with UM.Aqueous humor samples were collected from 38 patients with UM and 22 patients undergoing cataract surgery. Interleukin 6, 8 (IL-6, IL-8, respectively), interferon-inducible protein-10 (IP-10), placental growth factor1 (PIGF1), regulated on activation, normal T Cell expressed and secreted (RANTES), monocyte chemoattractant protein-1 (MCP-1), nerve growth factor-beta (NGF-ß), epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and vascular endothelia growth factor A (VEGF-A) were assessed by multiplex bead assay.In the study group, significantly higher concentrations of IL-6 (P = .006), IL-8 (P = .018), IP-10 (P = .004), RANTES (P = .008), MCP-1 (P = .02), NGF-ß (P = .013), EGF (P < .001), PIGF1 (P = .01), bFGF (P = .016), and VEGF (P = .017) were measured, when compared with the control group.Several angiogenic, inflammatory, and chemotactic cytokines are highly expressed in the aqueous humor of the UM eyes, which provides new insights into the pathophysiology of UM and could be potential targets for treatment.

Epidemiology and clinical features of intraocular lymphoma in Singapore.

INTRODUCTION: Intraocular lymphoma is rare. There are very few studies on intraocular lymphoma published from Asian countries. OBJECTIVE: To report our case series of intraocular lymphoma patients from a tertiary eye centre in Singapore. SUBJECTS AND METHODS: Nine patients with intraocular lymphoma managed between January 2005 and December 2014 were identified from Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) database. Demographic characteristics, clinical presentation, investigations performed and outcomes recorded. RESULTS: There were almost equal distribution between males (four patients) and females (five patients) with mean age of presentation was 60.3 years. Five patients had bilateral involvement and vitreo-retina was the most common site of infiltration. All of our patients had central nervous system involvement although four of them had presented with ocular manifestations initially. Anterior chamber fluid cytology, as a less invasive alternative to vitreous analysis was proven to be useful. The time from ocular presentation to diagnosis of ocular lymphoma was variable; from one day to 18 months. Mortality in our study group was 55% with death occurring 1 month to 8 years from diagnosis of intraocular lymphoma. CONCLUSION: Intraocular lymphoma is a masquerade syndrome that mimics chronicuveitis and poses a diagnostic challenge. The diagnosis is often delayed and despite the eventual diagnosis, the disease prognosis is poor even with aggressive treatment.

Increased Aqueous Humor CD4+/CD8+ Lymphocyte Ratio in Sarcoid Uveitis.

Purpose: To determine aqueous humor CD4+/CD8+ T-lymphocyte ratio changes in sarcoid and non-sarcoid uveitis with anterior chamber involvement. Methods: The case-control study includes 61 patients with either anterior uveitis, intermediate uveitis with anterior spill, or panuveitis. A total of 21 of them were categorized as sarcoid uveitis and 40 as non-sarcoid uveitis according to diagnostic criteria. CD4+/CD8+ ratio in the aqueous humor was determined using flow cytometry. Results: Significantly higher CD4+/CD8+ ratio in the aqueous humor was observed in patients with sarcoid uveitis (6.3 ± 1.4; mean ± SEM) compared to non-sarcoid uveitis (1.6 ± 0.1; mean ± SEM). Whole blood CD4+/CD8+ ratio was not elevated in subjects with sarcoid and non-sarcoid uveitis. Aqueous humor CD4+/CD8+ ratio >3.5 was observed to be associated with sarcoid uveitis (OR 38, 95% CI 7.0-205.2). Conclusion: Increased aqueous humor CD4+/CD8+ ratio in sarcoid uveitis. Immunophenotyping of localized lymphocytosis in aqueous humor could be utilized as an additional confirmatory marker for ocular sarcoidosis.

Genomic cfDNA Analysis of Aqueous Humor in Retinoblastoma Predicts Eye Salvage: The Surrogate Tumor Biopsy for Retinoblastoma.

Tumor-derived cell-free DNA (cfDNA) has biomarker potential; therefore, this study aimed to identify cfDNA in the aqueous humor (AH) of retinoblastoma eyes and correlate somatic chromosomal copy-number alterations (SCNA) with clinical outcomes, specifically eye salvage. AH was extracted via paracentesis during intravitreal injection of chemotherapy or enucleation. Shallow whole-genome sequencing was performed using isolated cfDNA to assess for highly recurrent SCNAs in retinoblastoma including gain of 1q, 2p, 6p, loss of 13q, 16q, and focal MYCN amplification. Sixty-three clinical specimens of AH from 29 eyes of 26 patients were evaluated; 13 eyes were enucleated and 16 were salvaged (e.g., saved). The presence of detectable SCNAs was 92% in enucleated eyes versus 38% in salvaged eyes (P = 0.006). Gain of chromosome 6p was the most common SCNA found in 77% of enucleated eyes, compared with 25% of salvaged eyes (P = 0.0092), and associated with a 10-fold increased odds of enucleation (OR, 10; 95% CI, 1.8-55.6). The median amplitude of 6p gain was 1.47 in enucleated versus 1.07 in salvaged eyes (P = 0.001). The presence of AH SCNAs was correlated retrospectively with eye salvage. The probability of ocular salvage was higher in eyes without detectable SCNAs in the AH (P = 0.0028), specifically 6p gain. This is the first study to correlate clinical outcomes with SCNAs in the AH from retinoblastoma eyes, as such these findings indicate that 6p gain in the aqueous humor is a potential prognostic biomarker for poor clinical response to therapy.Implications: The correlation of clinical outcomes and SCNAs in the AH identified in the current study requires prospective studies to validate these finding before SCNAs, like 6p gain, can be used to predict clinical outcomes at diagnosis. Mol Cancer Res; 16(11); 1701-12. ©2018 AACR.

Comparison of Aqueous and Vitreous Lymphocyte Populations From Two Rat Models of Experimental Uveitis.

Purpose: To compare lymphocyte populations present within inflamed eyes in two rat models of autoimmune uveitis. Methods: Experimental autoimmune uveitis (EAU) and primed mycobacterial uveitis (PMU) were initiated in Lewis rats. Aqueous and vitreous were collected at peak inflammation (PMU at day 2, EAU at day 14). The number of cells in the aqueous and vitreous was determined and compared for each eye and between the two models. Intraocular CD-19+ B cells, CD3+ T cells, and CD4+ or CD8+ T-cell subpopulations were identified by flow cytometry and compared between EAU and PMU. Results: The median number of cells/mL collected from PMU aqueous (7.98 × 107 cells/mL), was not significantly different from the number of cells collected from EAU aqueous (1.61 × 107 cells/mL, P = 0.94). EAU aqueous contains a significantly larger mononuclear population (median 61%, interquartile range [IQR] 44%-67%) than PMU (median 9%, IQR 8%-10% [P < 0.0001]). Within the mononuclear population, EAU and PMU aqueous demonstrate similar proportions of CD3+, CD4+ T cells. However, EAU has a larger CD3+, CD8+, T-cell population than PMU, and this population also demonstrates co-expression of CD45R. B cells comprise a significantly larger median percentage of cells in EAU aqueous (median 18%, IQR 15%-20%) compared to PMU (median 13%, IQR 9%-15%, P = 0.006). Conclusions: Flow cytometry analysis of intraocular lymphocytes from EAU and PMU identifies similarities and differences between the T-cell and B-cell populations present at peak inflammation. Complementary animal models that have well-defined mechanistic differences will improve our ability to test potential new therapies and bring meaningful advances into clinical practice for patients with uveitis.

Potential of Aqueous Humor as a Surrogate Tumor Biopsy for Retinoblastoma.

Importance: Retinoblastoma (Rb) is one of the first tumors to have a known genetic etiology. However, because biopsy of this tumor is contraindicated, it has not been possible to define the effects of secondary genetic changes on the disease course. Objective: To investigate whether the aqueous humor (AH) of Rb eyes has sufficient tumor-derived DNA to perform genetic analysis of the tumor, including DNA copy number alterations. Design, Setting, and Participants: This investigation was a case series study at a tertiary care hospital (Children's Hospital Los Angeles) with a large Rb treatment center. Cell-free DNA (cfDNA) was isolated from 6 AH samples from 3 children with Rb, including 2 after primary enucleation and 1 undergoing multiple intravitreous injections of melphalan for vitreous seeding. Samples were taken between December 2014 and September 2015. Main Outcomes and Measures: Measurable levels of nucleic acids in the AH and identification of tumor-derived DNA copy number variation in the AH. The AH was analyzed for DNA, RNA, and micro-RNA using Qubit high-sensitivity kits. Cell-free DNA was isolated from the AH, and sequencing library protocols were optimized. Shallow whole-genome sequencing was performed on an Illumina platform, followed by genome-wide chromosomal copy number variation profiling to assess the presence of tumor DNA fractions in the AH cfDNA of the 3 patients. One child's cfDNA from the AH and tumor DNA were subjected to Sanger sequencing to isolate the RB1 mutation. Results: Six AH samples were obtained from 3 Rb eyes in 3 children (2 male and 1 female; diagnosed at ages 7, 20, and 28 months). A corroborative pattern between the chromosomal copy number variation profiles of the AH cfDNA and tumor-derived DNA from the enucleated samples was identified. In addition, a nonsense RB1 mutation (Lys→STOP) from 1 child was also identified from the AH samples obtained during intravitreous injection of melphalan, which matched the tumor sample postsecondary enucleation. Sanger sequencing of the AH cfDNA and tumor DNA with polymerase chain reaction primers targeting RB1 gene c.1075A demonstrated this same RB1 mutation. Conclusions and Relevance: In this study evaluating nucleic acids in the AH from Rb eyes undergoing salvage therapy with intravitreous injection of melphalan, the results suggest that the AH can serve as a surrogate tumor biopsy when Rb tumor tissue is not available. This novel method will allow for analyses of tumor-derived DNA in Rb eyes undergoing salvage therapy that have not been enucleated.

Objective Quantification of Anterior Chamber Inflammation: Measuring Cells and Flare by Anterior Segment Optical Coherence Tomography.

PURPOSE: To assess the ability of swept-source (SS) optical coherence tomography (OCT) of the anterior segment (AS) to measure anterior chamber (AC) inflammation (both flare and cells) objectively. To compare OCT-derived inflammatory indices with standard techniques. DESIGN: Prospective evaluation of a diagnostic test. PARTICIPANTS: Patients diagnosed with anterior uveitis (active or inactive) and controls. METHODS: Participants underwent an AC inflammation evaluation including: clinical cell and flare grading and laser flare photometry (LFP). Uveitis patients were divided into active or inactive uveitis status according to clinical grading. Anterior segment SS-OCT scans were obtained for each participant. Tomographic images were analyzed to count the AC cells, and to calculate to absolute measurements of aqueous signal intensity. The absolute values were compared with the signal measured by the scan outside the eye, generating an optical density ratio (aqueous-to-air relative intensity [ARI] index). Correlations between OCT-derived AC inflammatory indexes and LFP, clinical grading, participant category (active or inactive uveitis, control), age, gender, and central corneal thickness (CCT) were assessed. MAIN OUTCOME MEASURES: Correlation between OCT-derived AC inflammatory indexes (ARI index and AC cells on OCT) and standard clinical techniques (LFP, clinical cell grading). RESULTS: Two hundred thirty-seven eyes (70 active uveitis, 97 inactive uveitis, and 70 controls) were included. Anterior chamber cells count on OCT did not differ between inactive uveitis and controls, but was significantly higher in active uveitis compared to the other categories (both P < 0.0001). All groups had different LFP (all P < 0.0001). Active uveitis had significantly higher ARI index compared with inactive uveitis and controls (both P < 0.0001). Interobserver agreement (intraclass correlation coefficient) for ARI index was 0.78. The ARI index correlated positively with age (P = 0.043) and negatively with CCT (P = 0.006). The ARI index correlated with LFP in the active uveitis group (P < 0.0001), but not in the others. Anterior chamber cells on OCT increased among all cell clinical grades (P < 0.0001). The ARI index increased among all flare clinical grades (P < 0.005). CONCLUSIONS: Anterior segment SS-OCT could be used for a comprehensive assessment of AC inflammation, providing objective measurements of inflammatory cells and aqueous flare.