Woodward AM, Argüeso P. Expression analysis of the transmembrane mucin MUC20 in human corneal and conjunctival epithelia. Invest Ophthalmol Vis Sci 2014;55(10):6132-8.Abstract
PURPOSE: Cell surface mucins are a group of highly O-glycosylated transmembrane glycoproteins responsible for the protection of epithelial cells on mucosal surfaces. The aim of this study was to investigate the localization and regulation of mucin 20 (MUC20) at the ocular surface. METHODS: Localization of MUC20 in human corneal and conjunctival epithelia was evaluated by immunofluorescence microscopy. Immortalized corneal (HCLE) and conjunctival (HCjE) cell lines were grown at different stages of differentiation and subjected to quantitative PCR and Western blot analyses. Cell surface proteins on apical cell membranes were biotinylated and isolated by neutravidin chromatography. RESULTS: The MUC20 was detected throughout the entire human ocular surface epithelia, predominantly in cell membranes within intermediate cell layers. In conjunctiva, MUC20 also was observed in the cytoplasm of apical cells within the stratified squamous epithelium, but not in goblet cells. Quantitative PCR and immunoblotting demonstrated expression of MUC20 in HCLE and HCjE cells. Induction of differentiation with serum-containing medium resulted in upregulation of MUC20 mRNA and protein. Biotin labeling of the surface of stratified cultures revealed low levels of MUC20 protein on apical glycocalyces. Further, MUC20 was not detected in the cell culture media or in human tears, suggesting that the extracellular domain of MUC20 is not released from the ocular surface as described previously for other cell surface mucins. CONCLUSIONS: Our results indicate that MUC20 is a novel transmembrane mucin expressed by the human corneal and conjunctival epithelia, and suggest that differential expression of MUC20 during differentiation has a role in maintaining ocular surface homeostasis.
Sheldon S, Quint J, Hecht H, Bowers AR. The effect of central vision loss on perception of mutual gaze. Optom Vis Sci 2014;91(8):1000-11.Abstract
PURPOSE: To evaluate the effects of central vision loss (CVL) on mutual gaze perception (knowing whether somebody else is looking at you), an important nonverbal visual cue in social interactions. METHODS: Twenty-three persons with CVL (visual acuity 20/50 to 20/200), 16 with a bilateral central scotoma and 7 without, and 23 age-matched control subjects completed a gaze perception task and a brief questionnaire. They adjusted the eyes of a life-size virtual head on a monitor at a 1-m distance until they either appeared to be looking straight at them or were at the extreme left/right or up/down positions at which the eyes still appeared to be looking toward them (defining the range of mutual gaze in the horizontal and vertical planes). RESULTS: The nonscotoma group did not differ from the control subjects in any gaze task measure. However, the gaze direction judgments of the scotoma group had significantly greater variability than those of the nonscotoma and control groups (p < 0.001). In addition, their mutual gaze range tended to be wider (p = 0.15), suggesting a more liberal judgment criterion. Contrast sensitivity was the strongest predictor of variability in gaze direction judgments followed by self-reported difficulties. CONCLUSIONS: Our results suggest that mutual gaze perception is relatively robust to CVL. However, a follow-up study that simulates less-than-optimal viewing conditions of everyday social interactions is needed. The gaze perception task holds promise as a research tool for investigating the effects of vision impairment on mutual gaze judgments. Self-reported difficulty and contrast sensitivity were both independent predictors of gaze perception performance, suggesting that the task captured higher-order as well as low-level visual abilities.
Panigrahy D, Adini I, Mamluk R, Levonyak N, Bruns CJ, D'Amore PA, Klagsbrun M, Bielenberg DR. Regulation of soluble neuropilin 1, an endogenous angiogenesis inhibitor, in liver development and regeneration. Pathology 2014;46(5):416-23.Abstract

Neuropilin-1 (NRP1) is a receptor for vascular endothelial growth factor (VEGF). A soluble isoform of Nrp1 (sNrp1) has not been described in the mouse. Our goal was to examine the expression of mouse sNrp1 during liver development and regeneration.sNrp1 was cloned from mouse liver. The expression of sNrp1 and VEGF was examined in mouse liver during post-natal development and regeneration using northern blot, western blot, in situ hybridisation, and immunohistochemical analyses. HGF/NRP1 binding was examined in vitro.A novel 588-amino acid sNrp1 isoform was found to contain the ligand binding regions of Nrp1. The adult liver expressed more sNrp1 than full-length Nrp1. In vivo, hepatocytes constitutively expressed VEGF and sNrp1 in the quiescent state. sNrp1 was highly up-regulated at P20, a time point coinciding with a plateau in liver and body weights. Following hepatectomy, endogenous levels of sNrp1 decreased during the rapid growth phase, and VEGF levels were highest just prior to and during the angiogenic phase. sNrp1 levels again rose 5-10 days post-hepatectomy, presumably to control regeneration. HGF protein bound NRP1 and binding was competed with sNRP1.We cloned a novel mouse sNrp1 isoform from liver and provide evidence that this endogenous angiogenesis inhibitor may regulate VEGF or HGF bioavailability during normal physiological growth and development as well as during liver regeneration.

Kodati S, Chauhan SK, Chen Y, Dohlman TH, Karimian P, Saban D, Dana R. CCR7 is critical for the induction and maintenance of Th17 immunity in dry eye disease. Invest Ophthalmol Vis Sci 2014;55(9):5871-7.Abstract

PURPOSE: We characterized antigen-presenting cell (APC)-relevant chemokine receptor expression in dry eye disease (DED), and investigated the effect of topical CC chemokine receptor (CCR)-7 blockade specifically on Th17 cell immunity and dry eye disease severity. METHODS: We induced DED in female C57BL/6 mice. Chemokine receptor expression by corneal APCs was characterized using immunohistochemistry. To determine the functional role of CCR7 in DED, mice were treated topically with either anti-CCR7, a control isotype antibody, or left untreated, and clinical disease severity, Th17 responses, and molecular markers of DED were quantified. RESULTS: Frequencies of CD11b(+) cells and their chemokine expression were increased in the cornea of DED mice. Mice treated topically with anti-CCR7 antibody displayed a significant reduction in clinical disease severity and Th17 response compared to the isotype and untreated groups. Topical CCR7 blockade was effective in ameliorating DED in its acute and chronic stages. CONCLUSIONS: Our findings suggest that CCR7-mediated trafficking of APCs drives the induction and maintenance of Th17 immunity in DED and that CCR7 blockade is effective in suppressing the immunopathogenic mechanisms in DED.

Ksander BR, Kolovou PE, Wilson BJ, Saab KR, Guo Q, Ma J, McGuire SP, Gregory MS, Vincent WJB, Perez VL, Cruz-Guilloty F, Kao WWY, Call MK, Tucker BA, Zhan Q, Murphy GF, Lathrop KL, Alt C, Mortensen LJ, Lin CP, Zieske JD, Frank MH, Frank NY. ABCB5 is a limbal stem cell gene required for corneal development and repair. Nature 2014;511(7509):353-7.Abstract
Corneal epithelial homeostasis and regeneration are sustained by limbal stem cells (LSCs), and LSC deficiency is a major cause of blindness worldwide. Transplantation is often the only therapeutic option available to patients with LSC deficiency. However, while transplant success depends foremost on LSC frequency within grafts, a gene allowing for prospective LSC enrichment has not been identified so far. Here we show that ATP-binding cassette, sub-family B, member 5 (ABCB5) marks LSCs and is required for LSC maintenance, corneal development and repair. Furthermore, we demonstrate that prospectively isolated human or murine ABCB5-positive LSCs possess the exclusive capacity to fully restore the cornea upon grafting to LSC-deficient mice in xenogeneic or syngeneic transplantation models. ABCB5 is preferentially expressed on label-retaining LSCs in mice and p63α-positive LSCs in humans. Consistent with these findings, ABCB5-positive LSC frequency is reduced in LSC-deficient patients. Abcb5 loss of function in Abcb5 knockout mice causes depletion of quiescent LSCs due to enhanced proliferation and apoptosis, and results in defective corneal differentiation and wound healing. Our results from gene knockout studies, LSC tracing and transplantation models, as well as phenotypic and functional analyses of human biopsy specimens, provide converging lines of evidence that ABCB5 identifies mammalian LSCs. Identification and prospective isolation of molecularly defined LSCs with essential functions in corneal development and repair has important implications for the treatment of corneal disease, particularly corneal blindness due to LSC deficiency.
Paramasivam S, Fay A, Fifi J, Berenstein A. O-015 image guided bleomycin sclerotherapy for orbital lymphatic malformation. J Neurointerv Surg 2014;6 Suppl 1:A8-9.Abstract

INTRODUCTION: Orbital lymphatic malformations (OLMs) are a unique subset of head and neck low flow vascular malformations, located either in the periorbital region or in the closed orbital cavity. We discuss our experience of minimally invasive strategies of treatment using advanced imaging and Bleomycin sclerotherapy to effectively treat these malformations. MATERIALS AND METHODS: Between 2008 and 2013, we have treated 54 cases of orbital low flow vascular malformations including 22 cases of OLMs of which 16 were treated using Bleomycin. This retrospective analysis was performed from patient charts, operative reports, operative images, pre-operative, and post-operative MR imaging. Bleomycin was used for sclerotherapy in all the cases with a maximum dose per session of treatment limited to 15 mgs. DIRECT PUNCTURE SCLEROTHERAPY TECHNIQUE: OLMs target was determined using pre-procedure MR imaging and direct puncture either per-cutaneous or per-conjunctival was achieved using ultrasound or i-guide guidance. In most lymphatic fluid was drained else the position confirmed with constrast injection under fluoroscopy. Bleomycin was used either undiluted or in various concentrations mixed with saline, or contrast material and recently we favor the use of Bleofoam mixed with 25% Human albumin and air. Microcystic LMs, were treated using gravity technique, the needle track was sealed with Surgiflo or Floseal. In cases of intra cystic or intra ocular haemorrhage with elevated orbital pressure, lateral canthotomy was performed to prevent permanent damage to vision and the contents of the orbit. Postoperatively, the patients recover in ICU and monitored for vision and orbital swelling. Bleomycin skin precautions were followed for 72 h in order to avoid skin hyperpigmentation. Optimal results were obtained at 6 to 8 weeks and assessed using follow-up MRI and ophthalmologic evaluation. RESULTS: The patient's age ranged from 1 to 45 years, with equal male to female ratio. Most cases (13/16) (80%) presented non acutely while three patients (20%) presented acutely with proptosis, visual disturbance and double vision due to haemorrhage within the malformation. Treatment completed in 14, one lost to follow up and the other is yet to be followed. The follow up period ranged from 6weeks to 6 months. 65% (9/14) needed less than three procedures while the remaining five patients needed between 3-5 procedures. All patients had improvement in proptosis; vision either remained stable or improved; volume reduction of more than 80% was noted in 57% (8/14), while the remaining patients 43% had volume reduction of 50-79%. One patient had transient mydriasis post procedure that completely recovered at three months. Another developed haemorrhage within the malformation immediate post sclerotherapy requiring lateral canthotomy, drainage and redo sclerotherapy. None of our patients developed skin pigmentation or pulmonary complication related to bleomycin usage. CONCLUSION: Bleomycin sclerotherapy combined with appropriate image guidance for precise target localization is an effective and safe treatment for OLMs. Bleomycin is a preferred sclerosant as it induces minimal inflammation and post procedure swelling. Standard precautions must be instituted to prevent cutaneous pigmentation and pulmonary fibrosis. DISCLOSURES: S. Paramasivam: None. A. Fay: None. J. Fifi: None. A. Berenstein: None.

Sahin O, Ziaei A. The role of methotrexate in resolving ocular inflammation after specific therapy for presumed latent syphilitic uveitis and presumed tuberculosis-related uveitis. Retina 2014;34(7):1451-9.Abstract
PURPOSE: This study was designed to investigate whether the antiinflammatory and antiproliferative activity of oral and intravitreal methotrexate (MTX) suppresses intraocular inflammation in patients with presumed latent syphilitic uveitis and presumed tuberculosis-related uveitis. METHODS: Interventional prospective study including three cases with presumed latent syphilitic uveitis treated with intravenous penicillin and oral MTX, and two cases with presumed tuberculosis-related uveitis treated with standard antituberculosis therapy and intravitreal MTX injections. Treatment efficacy of all cases was assessed by best-corrected visual acuity, fundus fluorescein angiography, and optical coherence tomography. RESULTS: Four eyes of 3 patients with presumed latent syphilitic uveitis had improved best-corrected visual acuity, suppression of intraocular inflammation, and resolution of cystoid macular edema in 6 months with oral MTX therapy. No recurrence of intraocular inflammation was observed in 6 months to 18 months of follow-up period after cessation of MTX. Two eyes of two patients with presumed tuberculosis-related uveitis showed improved best-corrected visual acuity, suppression of intraocular inflammation, and resolution of cystoid macular edema after intravitreal injections of MTX. No recurrence of intraocular inflammation was observed in 6 months to 8 months of follow-up period after cessation of antituberculous therapy. CONCLUSION: For the first time in the treatment of presumed latent syphilitic uveitis and presumed tuberculosis-related uveitis, we believe that MTX might have an adjunctive role to suppress intraocular inflammation, reduce uveitic macular edema, and prevent the recurrences of the diseases.
Feke GT, Bex PJ, Taylor CP, Rhee DJ, Turalba AV, Chen TC, Wand M, Pasquale LR. Effect of brimonidine on retinal vascular autoregulation and short-term visual function in normal tension glaucoma. Am J Ophthalmol 2014;158(1):105-112.e1.Abstract

PURPOSE: To assess whether brimonidine 0.15% alters retinal vascular autoregulation and short-term visual function in normal tension glaucoma patients who demonstrate retinal vascular dysregulation. DESIGN: Nonrandomized clinical trial. METHODS: In this prospective study, 46 normal tension glaucoma patients not previously treated with brimonidine underwent retinal vascular autoregulation testing and visual function assessment using frequency doubling technology perimetry and equivalent noise motion sensitivity testing. We measured blood flow in a major temporal retinal artery with subjects seated and then while reclined for 30 minutes. Patients having a change in retinal blood flow with posture change outside the range previously found in healthy subjects were classified as having retinal vascular dysregulation. They were treated with brimonidine 0.15% for 8 weeks and designated for retesting. RESULTS: Twenty-three patients demonstrated retinal vascular dysregulation at the initial visit. Younger age (P = .050) and diabetes (P = .055) were marginally significant risk factors for retinal vascular dysregulation. After the 8-week course with brimonidine, 14 of the 17 patients who completed the study showed a return of posture-induced retinal blood flow changes to levels consistent with normal retinal vascular autoregulation (P < .0001). We found no significant changes in frequency doubling technology perimetry or in motion detection parameters following treatment with brimondine (P > .09 for all tests performed). CONCLUSIONS: Brimonidine significantly improved impaired retinal vascular autoregulation in normal tension glaucoma patients, but short-term alteration in visual function could not be demonstrated.

Healy DY, Lee GN, Freitag SK, Bleier BS. Endoscopic bimanual approach to an intraconal cavernous hemangioma of the orbital apex with vascularized flap reconstruction. Ophthal Plast Reconstr Surg 2014;30(4):e104-6.Abstract

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.

Lee WJ, Sobrin L, Kang MH, Seong M, Kim YJ, Yi J-H, Miller JW, Cho HY. Ischemic diabetic retinopathy as a possible prognostic factor for chronic kidney disease progression. Eye (Lond) 2014;28(9):1119-25.Abstract
PURPOSE: To assess the value of diabetic retinopathy (DR) severity as a possible predictive prognostic factor for the progression of chronic kidney disease (CKD). PATIENTS AND METHODS: Retrospective cohort study. Patients (51) who were initially diagnosed with DR and CKD were enrolled and their medical records were evaluated. The following ophthalmic factors were assessed by fluorescein angiography at the initial visit: area of capillary nonperfusion, presence of neovascularization and vitreous hemorrhage, and DR grade. The effect of these factors on CKD progression over the 2-year period of the study, defined as doubling of serum creatinine or the development of end-stage renal disease requiring dialysis or renal transplant, was evaluated. RESULTS: The study included 51 patients with DR and CKD; of these, 11 patients (21.6%) were found to have proliferative DR (PDR) and seven patients (13.7%) had high-risk PDR at baseline. Patients with ischemic DR, who showed extensive capillary nonperfusion (≥ 10 optic disc areas) in the retina, had a greater risk for CKD progression (hazard ratio = 6.64; P = 0.002). CONCLUSION: We found that extensive capillary nonperfusion in the retina greatly increased the risk of progression of CKD in patients with DR. This suggests that the retina and the kidney may have shared risk factors for microvascular disease secondary to diabetes mellitus, and emphasizes the need for a team approach to diabetes care.
Sen NH, Vitale S, Gangaputra SS, Nussenblatt RB, Liesegang TL, Levy-Clarke GA, Rosenbaum JT, Suhler EB, Thorne JE, Foster SC, Jabs DA, Kempen JH. Periocular corticosteroid injections in uveitis: effects and complications. Ophthalmology 2014;121(11):2275-86.Abstract
PURPOSE: To evaluate the benefits and complications of periocular depot corticosteroid injections in patients with ocular inflammatory disorders. DESIGN: Multicenter, retrospective cohort study. PARTICIPANTS: A total of 914 patients (1192 eyes) who had received ≥ 1 periocular corticosteroid injection at 5 tertiary uveitis clinics in the United States. METHODS: Patients were identified from the Systemic Immunosuppressive Therapy for Eye Diseases Cohort Study. Demographic and clinical characteristics were obtained at every visit via medical record review by trained reviewers. MAIN OUTCOME MEASURES: Control of inflammation, improvement of visual acuity (VA) to ≥ 20/40, improvement of VA loss attributed to macular edema (ME), incident cataract affecting VA, cataract surgery, ocular hypertension, and glaucoma surgery. RESULTS: Among 914 patients (1192 eyes) who received ≥ 1 periocular injection during follow-up, 286 (31.3%) were classified as having anterior uveitis, 303 (33.3%) as intermediate uveitis, and 324 (35.4%) as posterior or panuveitis. Cumulatively by ≤ 6 months, 72.7% (95% CI, 69.1-76.3) of the eyes achieved complete control of inflammation and 49.7% (95% CI, 45.5-54.1) showed an improvement in VA from <20/40 to ≥ 20/40. Among the subset with VA <20/40 attributed to ME, 33.1% (95% CI, 25.2-42.7) improved to ≥ 20/40. By 12 months, the cumulative incidence of ≥ 1 visits with an intraocular pressure of ≥ 24 mmHg and ≥ 30 mmHg was 34.0% (95% CI, 24.8-45.4) and 15.0% (95% CI, 11.8-19.1) respectively; glaucoma surgery was performed in 2.4% of eyes (95% CI, 1.4-3.9). Within 12 months, among phakic eyes initially ≥ 20/40, the incidence of a reduction in VA to <20/40 attributed to cataract was 20.2% (95% CI, 15.9-25.6); cataract surgery was performed within 12 months in 13.8% of the initially phakic eyes (95% CI, 11.1-17.2). CONCLUSIONS: Periocular injections were effective in treating active intraocular inflammation and in improving reduced VA attributed to ME in a majority of patients. The response pattern was similar across anatomic locations of uveitis. Overall, VA improved in one half of the patients at some point within 6 months. However, cataract and ocular hypertension occurred in a substantial minority.
Grob SR, Gonzalez-Gonzalez LA, Daly MK. Management of mydriasis and pain in cataract and intraocular lens surgery: review of current medications and future directions. Clin Ophthalmol 2014;8:1281-9.Abstract

The maintenance of mydriasis and the control of postoperative pain and inflammation are critical to the safety and success of cataract and intraocular lens replacement surgery. Appropriate mydriasis is usually achieved by topical and/or intracameral administration of anticholinergic agents, sympathomimetic agents, or both, with the most commonly used being cyclopentolate, tropicamide, and phenylephrine. Ocular inflammation is common after cataract surgery. Topical steroids and nonsteroidal anti-inflammatory drugs are widely used because they have been proved effective to control postsurgical inflammation and decrease pain. Topical nonsteroidal anti-inflammatory drugs have also been shown to help maintain dilation. However, use of multiple preoperative drops for pupil dilation, inflammation, and pain control have been shown to be time consuming, resulting in delays to the operating room, and they cause dissatisfaction among perioperative personnel; their use can also be associated with systemic side effects. Therefore, ophthalmologists have been in search of new options to streamline this process. This article will review the current medications commonly used for intraoperative mydriasis, as well as pain and inflammation control. In addition, a new combination of ketorolac, an anti-inflammatory agent, and phenylephrine, a mydriatic agent has recently been designed to maintain intraoperative mydriasis and to reduce postoperative pain and irritation from intraocular lens replacement surgery. Two Phase III clinical trials evaluating this combination have demonstrated statistically significant differences when compared to placebo in maintaining intraoperative mydriasis (P<0.00001) and in reducing pain in the early postoperative period (P=0.0002). This medication may be of benefit for use in cataract and lens replacement surgery in the near future.

Hu Y, Lin H, Dib B, Atik A, Bouzika P, Lin C, Yan Y, Tang S, Miller JW, Vavvas DG. Cholesterol crystals induce inflammatory cytokines expression in a human retinal pigment epithelium cell line by activating the NF-κB pathway. Discov Med 2014;18(97):7-14.Abstract

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.

Lefebvre DR, Robinson-Bostom L, Migliori ME. Cellular neurothekeoma of the eyelid: a unique internal palpebral presentation. Ophthalmic Plast Reconstr Surg 2014;30(4):e91-2.Abstract
A 50-year-old woman presented with a mass lesion of the inferolateral palpebral conjunctiva similar in appearance to a chalazion, but unusual enough in presentation that excisional biopsy was initially performed. Histopathologic analysis revealed a dermal fibrohistiocytic neoplasm consistent with cellular neurothekeoma. Neurothekeoma is a benign tumor; the cellular variant is rare and of unclear histogenesis. Completely internal eyelid location is particularly rare, with other identifiable case reports of cellular neurothekeoma palpebrae referring to external or unspecified eyelid location. This case provides an example of the chalazion as masquerader and re-emphasizes the importance of maintaining a broad differential diagnosis and high index of suspicion regarding atypically appearing chalazia.
Contreras-Ruiz L, Ryan DS, Sia RK, Bower KS, Dartt DA, Masli S. Polymorphism in THBS1 gene is associated with post-refractive surgery chronic ocular surface inflammation. Ophthalmology 2014;121(7):1389-97.Abstract
PURPOSE: To determine the association of single nucleotide polymorphisms (SNPs) of the thrombospondin 1 (THBS1) gene with development of chronic ocular surface inflammation (keratoconjunctivitis) after refractive surgery. DESIGN: Retrospective cohort study. PARTICIPANTS: Active duty U.S. Army soldiers (n = 143) who opted for refractive surgery. METHODS: Conjunctival impression cytology samples collected from participants before the surgery were used to harvest DNA for genotyping 5 THBS1 SNPs (rs1478604, rs2228262, rs2292305, rs2228262, and rs3743125) using the Sequenom iPLEX Gold platform (Sequenom, San Diego, CA). Samples collected after surgery were used to harvest RNA for gene expression analysis by real-time polymerase chain reaction (PCR). Participants were followed for 1 year after surgery to monitor the status of keratoconjunctivitis. MAIN OUTCOME MEASURES: Genetic basis of the development of chronic keratoconjunctivitis after refractive surgery. RESULTS: Carriers of minor alleles of 3 SNPs each were found to be more susceptible to developing chronic keratoconjunctivitis (rs1478604: odds ratio [OR], 2.5; 95% confidence interval [CI], 1.41-4.47; P = 2.5 × 10(-3); rs2228262 and rs2292305: OR, 1.9; 95% CI, 1.05-3.51; P = 4.8 × 10(-2)). Carriers of the rs1478604 minor allele expressed significantly reduced levels of thrombospondin 1 (TSP1) (P = 0.042) and increased levels of an inflammatory cytokine associated with keratoconjunctivitis, interleukin-1β (P = 0.025), in their ocular surface epithelial cells compared with homozygous major allele controls. CONCLUSIONS: Genetic variation in the THBS1 gene that results in decreased expression of the encoded glycoprotein TSP1 in ocular surface epithelial cells significantly increases the susceptibility to develop chronic ocular surface inflammation after refractive surgery. Further investigation of THBS1 SNPs in a larger sample size is warranted.