BACKGROUND: Vision loss due to vascular disease of the retina is a leading cause of blindness in the world. Retinal angiomatous proliferation (RAP) is a subgroup of neovascular age-related macular degeneration (AMD), whereby abnormal blood vessels develop in the retina leading to debilitating vision loss and eventual blindness. The novel mouse strain, neoretinal vascularization 2 (NRV2), shows spontaneous fundus changes associated with abnormal neovascularization. The purpose of this study is to characterize the induction of pathologic angiogenesis in this mouse model. METHODS: The NRV2 mice were examined from postnatal day 12 (p12) to 3 months. The phenotypic changes within the retina were evaluated by fundus photography, fluorescein angiography, optical coherence tomography, and immunohistochemical and electron microscopic analysis. The pathological neovascularization was imaged by confocal microscopy and reconstructed using three-dimensional image analysis software. RESULTS: We found that NRV2 mice develop multifocal retinal depigmentation in the posterior fundus. Depigmented lesions developed vascular leakage observed by fluorescein angiography. The spontaneous angiogenesis arose from the retinal vascular plexus at postnatal day (p)15 and extended toward retinal pigment epithelium (RPE). By three months of age, histological analysis revealed encapsulation of the neovascular lesion by the RPE in the photoreceptor cell layer and subretinal space. CONCLUSIONS: The NRV2 mouse strain develops early neovascular lesions within the retina, which grow downward towards the RPE beginning at p15. This retinal neovascularization model mimics early stages of human retinal angiomatous proliferation (RAP) and will likely be a useful in elucidating targeted therapeutics for patients with ocular neovascular disease.
The aim of this study was to describe a transnasal endoscopic bimanual technique for the removal of an intraconal orbital apex cavernous hemangioma. Report of a surgical technique. A 39-year-old woman with unilateral visual loss and proptosis was found to have an intraconal orbital apex mass consistent radiographically with cavernous hemangioma. Because of its posteromedial location within the orbit, a transnasal 4-handed endoscopic technique was used with pedicled nasoseptal flap reconstruction. The tumor was excised, and the patient had no complications. The transnasal endoscopic approach to orbital apex cavernous hemangioma excision is a viable surgical approach for these difficult to access lesions. The medial orbital wall may be simultaneously reconstructed to prevent diplopia and enophthalmos.
Combined oxidative phosphorylation deficiency type 7 (COXPD7) is a rare disorder of mitochondrial metabolism that results in optic atrophy and Leigh syndrome-like disease. We describe 2 siblings with compound heterozygous mutations in the recently identified C12orf65 gene who presented with optic atrophy and mild developmental delays and subsequently developed bilateral, symmetric lesions in the brainstem reminiscent of Leigh syndrome. Repeat neuroimaging demonstrated reversibility of the findings in 1 sibling and persistent metabolic stroke in the other. This article highlights the phenotypic manifestations from a novel mutation in the C12orf65 gene and reviews the clinical presentation of the 5 other individuals reported to date who carry mutations in this gene.
OBJECTIVE: We characterized and correlated endothelial progenitor cells (EPCs) and circulating progenitor cells (CPCs) with lack of vascular complications in the Joslin Medalist Study in patients with type 1 diabetes for 50 years or longer. RESEARCH DESIGN AND METHODS: EPC and CPC levels were ascertained by flow cytometry and compared among Medalists (n = 172) with or without diabetic retinopathy (DR; n = 84 of 162), neuropathy (n = 94 of 165), diabetic nephropathy (DN; n = 18 of 172), cardiovascular disease (CVD; n = 63 of 168), age-matched controls (n = 83), type 2 diabetic patients (n = 36), and younger type 1 diabetic patients (n = 31). Mitogens, inflammatory cytokines, and oxidative markers were measured in blood or urine. Migration of cultured peripheral blood mononuclear cells (PBMCs) from Medalists and age-matched controls were compared. RESULTS: Medalists' EPC and CPC levels equaled those of their nondiabetic age-matched controls, were 10% higher than those in younger type 1 diabetic patients, and were 20% higher than those in age-matched type 2 diabetic patients. CPC levels were 15% higher in Medalists without CVD and nephropathy than in those affected, whereas EPC levels were significantly higher in those without peripheral vascular disease (PVD) than those with PVD. Stromal-derived factor 1 (SDF-1) levels were higher in Medalists with CVD, DN, and DR than in those not affected and their controls. IGF-I levels were lower in Medalists and correlated inversely with CPC levels. Additionally, cultured PBMCs from Medalists migrated more than those from nondiabetic controls. CONCLUSIONS: Normal levels of EPC and CPC in the Medalists, unlike other groups with diabetes, especially those without CVD, support the idea that endogenous factors exist to neutralize the adverse effects of metabolic abnormalities of diabetes on vascular tissues.
PURPOSE: To establish normal noninvasive tear film breakup time (NI-BUT) values in the Chinese population and investigate age-related changes in NI-BUT using a newly developed Keratograph. METHODS: Forty normal volunteers with a mean age of 32.8 ± 16.7 years were recruited for this study. Clinical and demographic data, including age, gender, fluorescein tear film breakup time (FBUT), and Schirmer I test values were collected from the subjects. Noninvasive tear film breakup time was measured using a new method based on a corneal topographer equipped with a modified scan software. The correlations between the NI-BUT, age, and gender were determined. RESULTS: In total, a significant difference between the NI-BUT and the FBUT was found (4.9 ± 2.4 seconds vs. 9.0 ± 3.0 seconds; p < 0.001). No statistically significant difference in the NI-BUT was observed between the male and female subjects (5.5 ± 2.0 seconds vs. 4.5 ± 2.5 seconds; p = 0.137). In addition, no significant correlation was detected between the NI-BUT and age (0.143, p = 0.321). CONCLUSIONS: The NI-BUT values found in this study are much lower than those of previous reports. Our results show no significant differences in tear film stability with age. The tear physiology of the Chinese population may not be the same as in Western populations.
The high temperature requirement A1 (HTRA1) is a potent protease involved in many diseases, including rheumatoid arthritis (RA). However, the regulatory mechanisms that control HTRA1 expression need to be determined. In this study, we demonstrated that IFN-γ significantly inhibited the basal and LPS-induced HTRA1 expression in fibroblasts and macrophages, which are two major cells for HTRA1 production in RA. Importantly, the inhibitory effect of IFN-γ on HTRA1 expression was evidenced in collagen-induced arthritis (CIA) mouse models and in human RA synovial cells. In parallel with the enhanced CIA incidence and pathological changes in IFN-γ-deficient mice, HTRA1 expression in the joint tissues was also increased as determined by real-time PCR and Western blots. IFN-γ deficiency increased the incidence of CIA and the pathological severity in mice. Neutralization of HTRA1 by Ab significantly reversed the enhanced CIA frequency and severity in IFN-γ-deficient mice. Mechanistically, IFN-γ negatively controls HTRA1 expression through activation of p38 MAPK/STAT1 pathway. Dual luciferase reporter assay and chromatin immunoprecipitation analysis showed that STAT1 could directly bind to HTRA1 promoter after IFN-γ stimulation. This study offers new insights into the molecular regulation of HTRA1 expression and its role in RA pathogenesis, which may have significant impact on clinical therapy for RA and possibly other HTRA1-related diseases, including osteoarthritis, age-related macular degeneration, and cancer.
It is known that inoculation of antigen into the anterior chamber (a.c.) of a mouse eye induces a.c.-associated immune deviation (ACAID), which is mediated in part by antigen-specific local and peripheral tolerance to the inciting antigen. ACAID can also be induced in vivo by intravenous (i.v.) inoculation of ex-vivo-generated tolerogenic antigen-presenting cells (TolAPC). The purpose of this study was to test if in-vitro-generated retinal antigen-pulsed TolAPC suppressed established experimental autoimmune uveitis (EAU). Retinal antigen-pulsed TolAPC were injected i.v. into mice 7 days post-induction of EAU. We observed that retinal antigen-pulsed TolAPC suppressed the incidence and severity of the clinical expression of EAU and reduced the expression of associated inflammatory cytokines. Moreover, extract of whole retina efficiently replaced interphotoreceptor retinoid-binding protein (IRBP) in the preparation of TolAPC used to induce tolerance in EAU mice. Finally, the suppression of EAU could be transferred to a new set of EAU mice with CD8⁺ but not with CD4⁺ regulatory T cells (T(reg)). Retinal antigen-pulsed TolAPC suppressed ongoing EAU by inducing CD8⁺ T(reg) cells that, in turn, suppressed the effector activity of the IRBP-specific T cells and altered the clinical symptoms of autoimmune inflammation in the eye. The ability to use retinal extract for the antigen raises the possibility that retinal extract could be used to produce autologous TolAPC and then used as therapy in human uveitis.
PURPOSE: To investigate the expression of inflammatory cytokines in ARPE-19 cells after stimulation with cholesterol crystals. METHODS: APRE-19 cells were cultured, primed with IL-1α, and treated with cholesterol crystals under different concentrations. Inflammatory cytokines (mature-IL-1β, IL-6, and IL-8) in supernatant and inflammatory cytokines (pro-IL-1β, IL-18) in cell lysate were detected by western blot. The NF-κB pathway inhibitor BAY 11-7082 was used to determine the pathway of cytokine expression. RESULTS: Cholesterol crystals did not induce the nucleotide-binding domain leucine-rich repeat containing family, pyrin domain containing 3 (NLRP3) inflammasome, but did increase pro-IL-1β expression in ARPE-19 cells. Cholesterol crystals increased pro-IL-1β expression by activating the NF-κB pathway. Cholesterol crystal activation of the NF-κB pathway also leads to increased IL-6 and IL-8 expression. CONCLUSION: Cholesterol crystals can induce inflammatory cytokine expression in ARPE-19 cells by activating the NF-κB pathway.
Aims. Increasing evidence shows that imbalanced suppressive drive prior to binocular combination may be the key factor in amblyopia. We described a novel binocular approach, interocular shift of visual attention (ISVA), for treatment of amblyopia in adult patients. Methods. Visual stimuli were presented anaglyphically on a computer screen. A square target resembling Landolt C had 2 openings, one in red and one in cyan color. Through blue-red goggles, each eye could only see one of the two openings. The patient was required to report the location of the opening presented to the amblyopic eye. It started at an opening size of 800 sec of arc, went up and down in 160 sec of arc step, and stopped when reaching the 5th reversals. Ten patients with anisometropic amblyopia older than age 14 (average age: 26.7) were recruited and received ISVA treatment for 6 weeks, with 2 training sessions per day. Results. Both Titmus stereopsis (z = -2.809, P = 0.005) and Random-dot stereopsis (z = -2.317, P = 0.018) were significantly improved. Average improvement in best corrected visual acuity (BCVA) was 0.74 line (t = 5.842, P < 0.001). Conclusions. The ISVA treatment may be effective in treating amblyopia and restoring stereoscopic function.
PURPOSE: The purpose of this study is to evaluate the functional and morphological changes in subretinal xenografts of human retinal progenitor cells (hRPCs) in B6 mice treated with Cyclosporin A (CsA; 210 mg/l in drinking water). METHODS: The hRPCs from human fetal eyes were isolated and expanded for transplantation. These cells, with green fluorescent protein (GFP) at 11 passages, were transplanted into the subretinal space in B6 mice. A combination of invasive and noninvasive approaches was used to analyze the structural and functional consequences of the subretinal injection of the hRPCs. The process of change was monitored using spectral domain optical coherence tomography (SDOCT), histology, and electroretinography (ERG) at 3 days, 1 week, and 3 weeks after transplantation. Cell counts were used to evaluate the survival rate with a confocal microscope. ERGs were performed to evaluate the physiologic changes, and the structural changes were evaluated using SDOCT and histological examination. RESULTS: The results of the histological examination showed that the hRPCs gained a better survival rate in the mice treated with CsA. The SDOCT showed that the bleb size of the retinal detachment was significantly decreased, and the retinal reattachment was nearly complete by 3 weeks. The ERG response amplitudes in the CsA group were less decreased after the injection, when compared with the control group, in the dark-adapted and light-adapted conditions. However, the cone-mediated function in both groups was less affected by the transplantation after 3 weeks than the rod-mediated function. CONCLUSIONS: Although significant functional and structural recovery was observed after the subretinal injection of the hRPCs, the effectiveness of CsA in xenotransplantation may be a novel and potential approach for increasing retinal progenitor cell survival.
Watching 3D content using a stereoscopic display may cause various discomforting symptoms, including eye strain, blurred vision, double vision, and motion sickness. Numerous studies have reported motion-sickness-like symptoms during stereoscopic viewing, but no causal linkage between specific aspects of the presentation and the induced discomfort has been explicitly proposed. Here, we describe several causes, in which stereoscopic capture, display, and viewing differ from natural viewing resulting in static and, importantly, dynamic distortions that conflict with the expected stability and rigidity of the real world. This analysis provides a basis for suggested changes to display systems that may alleviate the symptoms, and suggestions for future studies to determine the relative contribution of the various effects to the unpleasant symptoms.
Hysi PG, Cheng C-Y, Springelkamp H, Macgregor S, Bailey JCN, Wojciechowski R, Vitart V, Nag A, Hewitt AW, Höhn R, Venturini C, Mirshahi A, Ramdas WD, Thorleifsson G, Vithana E, Khor C-C, Stefansson AB, Liao J, Haines JL, Amin N, Wang YX, Wild PS, Ozel AB, Li JZ, Fleck BW, Zeller T, Staffieri SE, Teo Y-Y, Cuellar-Partida G, Luo X, Allingham RR, Richards JE, Senft A, Karssen LC, Zheng Y, Bellenguez C, Xu L, Iglesias AI, Wilson JF, Kang JH, van Leeuwen EM, Jonsson V, Thorsteinsdottir U, Despriet DDG, Ennis S, Moroi SE, Martin NG, Jansonius NM, Yazar S, Tai E-S, Amouyel P, Kirwan J, van Koolwijk LME, Hauser MA, Jonasson F, Leo P, Loomis SJ, Fogarty R, Rivadeneira F, Kearns L, Lackner KJ, de Jong PTVM, Simpson CL, Pennell CE, Oostra BA, Uitterlinden AG, Saw S-M, Lotery AJ, Bailey-Wilson JE, Hofman A, Vingerling JR, Maubaret C, Pfeiffer N, Wolfs RCW, Lemij HG, Young TL, Pasquale LR, Delcourt C, Spector TD, Klaver CCW, Small KS, Burdon KP, Stefansson K, Wong T-Y, Wong T-Y, Wong T-Y, Wong T-Y, Viswanathan A, Mackey DA, Craig JE, Wiggs JL, van Duijn CM, Hammond CJ, Aung T. Genome-wide analysis of multi-ancestry cohorts identifies new loci influencing intraocular pressure and susceptibility to glaucoma. Nat Genet 2014;46(10):1126-30.Abstract
Elevated intraocular pressure (IOP) is an important risk factor in developing glaucoma, and variability in IOP might herald glaucomatous development or progression. We report the results of a genome-wide association study meta-analysis of 18 population cohorts from the International Glaucoma Genetics Consortium (IGGC), comprising 35,296 multi-ancestry participants for IOP. We confirm genetic association of known loci for IOP and primary open-angle glaucoma (POAG) and identify four new IOP-associated loci located on chromosome 3q25.31 within the FNDC3B gene (P = 4.19 × 10(-8) for rs6445055), two on chromosome 9 (P = 2.80 × 10(-11) for rs2472493 near ABCA1 and P = 6.39 × 10(-11) for rs8176693 within ABO) and one on chromosome 11p11.2 (best P = 1.04 × 10(-11) for rs747782). Separate meta-analyses of 4 independent POAG cohorts, totaling 4,284 cases and 95,560 controls, showed that 3 of these loci for IOP were also associated with POAG.
PURPOSE: To assess the effects of intravitreal ranibizumab on diabetic retinopathy (DR) severity when administered for up to 3 years, evaluate the effect of delayed initiation of ranibizumab therapy on DR severity, and identify baseline patient characteristics associated with the development of proliferative DR (PDR). DESIGN: Exploratory analyses of phase III, randomized, double-masked, sham-controlled multicenter clinical trials. PARTICIPANTS: Adults with diabetic macular edema (DME) (N = 759), baseline best-corrected visual acuity 20/40 to 20/320 Snellen equivalent, and central foveal thickness ≥275 μm. METHODS: Patients were randomized to monthly 0.3 or 0.5 mg ranibizumab or sham injections. Sham participants could switch to 0.5 mg ranibizumab during the third year (sham/0.5 mg crossover). Baseline risk factors were evaluated to explore potential associations with development of PDR. Time to first development of PDR was analyzed by Kaplan-Meier methods to calculate cumulative probabilities by group. MAIN OUTCOME MEASURES: Study eye change on the Early Treatment Diabetic Retinopathy Study severity scale and a composite clinical outcome evaluating progression to PDR based on photographic changes plus clinically important events defining PDR. RESULTS: At month 36, a greater proportion of ranibizumab-treated eyes had ≥2- or ≥3-step DR improvement compared with sham/0.5 mg crossover. A ≥3-step improvement was achieved at 36 months by 3.3%, 15.0%, and 13.2% of sham/0.5 mg, 0.3 mg, and 0.5 mg ranibizumab-treated eyes, respectively (P < 0.0001). Through 36 months, 39.1% of eyes in the sham/0.5 mg group developed PDR, as measured by composite outcome, compared with 18.3% and 17.1% of eyes treated with 0.3 or 0.5 mg ranibizumab, respectively. The presence of macular capillary nonperfusion at baseline seems to be associated with progression to PDR in ranibizumab-treated eyes but did not meaningfully influence visual acuity improvement in eyes with DME after ranibizumab therapy. CONCLUSIONS: Ranibizumab, as administered to patients with DME for 12 to 36 months in these studies, can both improve DR severity and prevent worsening. Prolonged delays in initiation of ranibizumab therapy may limit this therapeutic effect. Although uncommon, the development of PDR still occurs in a small percentage of eyes undergoing anti-vascular endothelial growth factor therapy and may be related to the presence of macular nonperfusion.
Although more than one type of visual opsin is present in the retina of most vertebrates, it was thought that each type of photoreceptor expresses only one opsin. However, evidence has accumulated that some photoreceptors contain more than one opsin, in many cases as a result of a developmental transition from the expression of one opsin to another. The salamander UV-sensitive (UV) cone is particularly notable because it contains three opsins (Makino and Dodd  J Gen Physiol 108:27-34). Two opsin types are expressed at levels more than 100 times lower than the level of the primary opsin. Here, immunohistochemical experiments identified the primary component as a UV cone opsin and the two minor components as the short wavelength-sensitive (S) and long wavelength-sensitive (L) cone opsins. Based on single-cell recordings of 156 photoreceptors, the presence of three components in UV cones of hatchlings and terrestrial adults ruled out a developmental transition. There was no evidence for multiple opsin types within rods or S cones, but immunohistochemistry and partial bleaching in conjunction with single-cell recording revealed that both single and double L cones contained low levels of short wavelength-sensitive pigments in addition to the main L visual pigment. These results raise the possibility that coexpression of multiple opsins in other vertebrates was overlooked because a minor component absorbing at short wavelengths was masked by the main visual pigment or because the expression level of a component absorbing at long wavelengths was exceedingly low.
BACKGROUND: Patients with Parkinson's disease (PD) experience visual hallucinations, which may be related to decreased contrast sensitivity (ie, the ability to discern shades of grey). OBJECTIVE: The objective of this study was to investigate if an online research platform can be used to survey patients with Parkinson's disease regarding visual hallucinations, and also be used to assess visual contrast perception. METHODS: From the online patient community, PatientsLikeMe, 964 members were invited via email to participate in this study. Participants completed a modified version of the University of Miami Parkinson's disease hallucinations questionnaire and an online vision test. RESULTS: The study was completed by 27.9% (269/964) of those who were invited: 56.9% of this group had PD (153/269) and 43.1% (116/269) were non-Parkinson's controls. Hallucinations were reported by 18.3% (28/153) of the Parkinson's group. Although 10 subjects (9%) in the control group reported experiencing hallucinations, only 2 of them actually described formed hallucinations. Participants with Parkinson's disease with a mean of 1.75 (SD 0.35) and the control group with a mean of 1.85 (SD 0.36) showed relatively good contrast perception as measured with the online letter test (P=.07). People who reported hallucinations showed contrast sensitivity levels that did not differ from levels shown by people without hallucinations (P=.96), although there was a trend towards lower contrast sensitivity in hallucinators. CONCLUSIONS: Although more Parkinson's responders reported visual hallucinations, a significant number of non-Parkinson's control group responders also reported visual hallucinations. The online survey method may have failed to distinguish between formed hallucinations, which are typical in Parkinson's disease, and non-formed hallucinations that have less diagnostic specificity. Multiple questions outlining the nature of the hallucinations are required. In a clinical interview, the specific nature of the hallucination would be further refined to rule out a vague description that does not indicate a true, formed visual hallucination. Contrary to previous literature, both groups showed relatively good contrast sensitivity, perhaps representing a ceiling effect or limitations of online testing conditions that are difficult to standardize. Steps can be taken in future trials to further standardize online visual function testing, to refine control group parameters and to take steps to rule out confounding variables such as comorbid disease that could be associated with hallucinations. Contacting subjects via an online health social network is a novel, cost-effective method of conducting vision research that allows large numbers of individuals to be contacted quickly, and refinement of questionnaires and visual function testing may allow more robust findings in future research.
An exuberant corneal pannus usually develops in adults with a history of surgery or trauma in the anterior central stroma and appears as a glistening, vascularized, moderately elevated, well circumscribed white nodule. We describe a 78-year-old woman with such a pannus, which in the past has typically been referred to as keloidal or hypertrophic. The involved eye had only light perception, and she underwent a penetrating keratoplasty that improved her vision to 20/100. Histopathologic and immunohistochemical evaluations of a the specimen disclosed a reactive spindle cell stromal proliferation of myofibroblasts that were smooth muscle actin positive with a low Ki67 proliferation index. Desmin, caldesmon, and calponin were negative, in keeping with the incomplete myofilamentary differentiation of a myofibroblast. There was a generous admixture of CD68/163-positive histiocytes and dispersed C3/5-positive T-lymphocytes. An absence of CD138- and IgG4-positive plasma cells ruled out an IgG4-related disease. For a lesion to be keloidal, the collagen must have a thick hyaline character, sharp edges, and a sparsity of intervening cells and vessels. A hypertrophic pannus would be composed of large swollen cells not necessarily increased in number. We therefore recommend adoption of the term hyperplastic for lesions like that described here because of the obvious increase in cellularity from proliferating myofibroblasts and the lack of true keloidal collagen.
PURPOSE: To evaluate the clinical and immunopathologic features of 2 patients with bilateral dacryoadenitis associated with regional enteritis. DESIGN: Retrospective, clinicopathologic study. METHODS: Clinical records, photographs, and imaging studies were reviewed and microscopic sections of lacrimal gland biopsy samples were critically re-evaluated. The microscopic slides were stained with hematoxylin and eosin, special stains for organisms, and a range of immunohistochemical biomarkers, including CD3, CD4, CD5, CD8, CD20, CD68, CD138, CD1a, and immunoglobulins Ig G, IgG4, and IgA. RESULTS: Both patients were young women with a well-established diagnosis of regional enteritis. Histopathologic examination of biopsy samples disclosed moderate intraparenchymal fibrosis and lymphoplasmacytic infiltrates without lymphoid follicles. Small to medium intraparenchymal, noncaseating granulomas lacking multinucleated giant cells and, in 1 patient, CD68-positive and CD1a-negative palisading granulomas in widened interlobular fibrous septa were detected. Vasculitis and IgG4 plasma cells were not observed. Additional immunohistochemical studies revealed that CD8 T lymphocytes (suppressor or cytotoxic subset) predominated over CD4-positive T lymphocytes (helper cells) surrounding the necrobiotic foci and were intermixed with the CD68-positive histiocytes in the absence of CD20 B lymphocytes. Special stains for organisms demonstrated negative results. CONCLUSIONS: Dacryoadenitis is the rarest form of ocular adnexal involvement in regional enteritis, which affects the orbit far more frequently than ulcerative colitis. It is a granulomatous process with the possibility of palisading necrobiotic foci. In contrast, ulcerative colitis causes an interstitial lymphocytic and nongranulomatous myositis. Sarcoidosis, Wegener granulomatosis, and pseudorheumatoid nodules must be ruled out. Treatment options entail a wide variety of agents with selection based on empirical considerations and tailored to the patient's symptoms.
PURPOSE: To describe the diagnostic clinical findings and immunopathology of a fibrous histiocytoma of the upper eyelid tarsus of a 42-year-old man. METHODS: Analysis of clinical features and results of histopathologic and immunohistochemical evaluations using antibodies against the biomarkers smooth muscle actin, S100, CD1a, CD3, CD20, CD31, CD34, CD68, CD163, factor XIIIa, adipophilin, androgen receptor, and Ki-67. RESULTS: The skin moved over a firm lesion that was situated in the tarsus and protruded from the palpebral conjunctiva as a whitish flat-domed noninflamed mass that had caused an irritating corneal epitheliopathy. Histopathologically, there was a storiform or spiral nebular growth pattern, a moderate amount of intercellular collagen, and no nuclear atypia or mitotic activity. The main immunohistochemical findings were CD34 and smooth muscle actin negativity among the tumor cells and a scarcity of CD68/163 histiocytes. Androgen receptors were identified in the tumor cells. CONCLUSIONS: CD34 histiocytoma of the tarsus is a rare, benign, and separate entity from a CD34 solitary fibrous tumor. Conservative tarsectomy is curative.