Trends in Vitreoretinal Procedures for Medicare Beneficiaries, 2000 to 2014.

TOPIC: The purpose of this study was to identify changes in use for vitreoretinal procedures by measuring the number of allowed services using data from the US Medicare Part B Fee-for-Service (FFS) beneficiaries and their providers. CLINICAL RELEVANCE: To analyze vitreoretinal procedural trends, which may indicate standard of care and importance of developing methods of treatments. METHODS: Medicare Part B National Summary Data Files for calendar years 2000 to 2014 were used to identify the number of allowed services for vitreoretinal procedures and commonly used pharmacologic agents. Linear regression analysis was performed to identify trends in use. MAIN OUTCOME MEASURES: To analyze vitreoretinal procedural trends, which may indicate standard of care and importance of developing methods of treatments. RESULTS: Vitreoretinal procedures grew 6-fold from 2000 to 2014. Intravitreal injections were the primary driver of growth. A total of 2922 injections were performed in 2000, compared with 2 619 950 injections in 2014 (P < 0.01). Scleral buckling declined from 6502 procedures in 2000 to 1260 procedures in 2014 (P < 0.01), whereas vitrectomy use for retinal detachment increased from 13 814 surgeries in 2008 to 19 288 surgeries in 2014 (P < 0.01). Focal laser treatments declined from 188 351 procedures in 2002 to 83 379 procedures in 2014 (P < 0.01). Panretinal photocoagulation treatments declined from 109 840 procedures in 2004 to 81 005 procedures in 2014 (P < 0.01). CONCLUSIONS: Vitreoretinal practice patterns changed significantly from 2000 to 2014. Intravitreal injections increased by 89 563%. Intravitreal injections accounted for 0.55% of all vitreoretinal procedures in 2000 and increased to 87% in 2014. Scleral buckling sharply declined, and preference for retinal detachment repair shifted further toward vitrectomy with a distribution of 83% vitrectomy, 5% scleral buckling, and 12% pneumatic retinopexy in 2014. Use of laser photocoagulation significantly declined for treatment of macular edema and proliferative retinopathy. Cryotherapy procedures declined across all indications.

Surgical Assistant Use in Vitreoretinal Surgery.

PURPOSE: To evaluate the use of surgical assistants in vitreoretinal surgery. DESIGN: Database study. PARTICIPANTS: Data from US Medicare Part B fee-for-service beneficiaries and their providers. METHODS: Medicare Part B National Summary Data Files for calendar years 2000 through 2014 were used to identify the number of services billed by assistant and primary surgeons for vitreoretinal surgeries. The proportion of procedures involving an assistant was determined for each year. Linear regression analysis was performed to identify trends in use. MAIN OUTCOME MEASURE: Percentage of vitreoretinal procedures using an assistant surgeon. RESULTS: From 2000 through 2014, 12% of eligible vitreoretinal surgeries (216 637/1 808 377) involved a surgical assistant. In 2000, 14% (13 115/94 742) of vitreoretinal surgeries used a surgical assistant compared with 10% in 2014 (13 360/136 945). In this 15-year period, there was a statistically significant decline in the proportion of vitreoretinal procedures using an assistant (P < 0.01). CONCLUSIONS: From 2000 through 2014, surgical assistants were used in 12% of vitreoretinal surgeries. The percentage of cases using an assistant declined from 14% in 2000 to 10% in 2014 (P < 0.01), a 29% decline. This decline may be secondary to technological advances in vitrectomy, which confer greater surgeon independence, and a marked decline in scleral buckling procedures.

Association of rivaroxaban anticoagulation and spontaneous vitreous hemorrhage.

IMPORTANCE: Rivaroxaban is an anticoagulant prescribed for the management of atrial fibrillation. We describe a correlation between rivaroxaban and spontaneous vitreous hemorrhage. OBSERVATIONS: Three patients developed spontaneous vitreous hemorrhage after initiating rivaroxaban anticoagulation. All 3 patients were taking an additional anticoagulant at the time of hemorrhage. CONCLUSIONS AND RELEVANCE: Rivaroxaban is increasingly prescribed as a replacement for warfarin sodium in the management of atrial fibrillation. Rivaroxaban anticoagulation may be associated with spontaneous vitreous hemorrhage. The risk of hemorrhage may be particularly elevated during the transition period when patients are switched from baseline anticoagulant to rivaroxaban therapy and are taking both anticoagulants simultaneously.

The role of fundus autofluorescence in late-onset retinitis pigmentosa (LORP) diagnosis.

PURPOSE: To demonstrate the utility and characteristics of fundus autofluorescence in late-onset retinitis pigmentosa. METHODS: Observational case series. Patients diagnosed with late-onset retinitis pigmentosa were identified retrospectively in an institutional setting. Twelve eyes of six patients were identified and medical records were reviewed. RESULTS: All patients presented with slowly progressive peripheral field loss and initial clinical examination revealed only subtle retinal changes. There was a notable lack of intraretinal pigment migration in all patients. Five out of six patients underwent magnetic resonance imaging of the brain to rule out intracranial processes and all were referred from another ophthalmologist for further evaluation. Fundus autofluorescence was ultimately employed in all patients and revealed more extensive retinal pathology than initially appreciated on clinical examination. Fundus autofluorescence directed the workup toward a retinal etiology in all cases and led to the eventual diagnosis of late-onset retinitis pigmentosa through electroretinogram testing. CONCLUSION: Fundus autofluorescence may be a more sensitive marker for retinal pathology than stereo fundus biomicroscopy alone in late-onset retinitis pigmentosa. Early use of fundus autofluorescence imaging in the evaluation of patients with subtle retinal lesions and complaints of peripheral field loss may be an effective strategy for timely and cost-efficient diagnosis.

Relationship among visual field, blood flow, and neural structure measurements in glaucoma.

PURPOSE: To determine the relationship among visual field, neural structural, and blood flow measurements in glaucoma. METHODS: Case-control study. Forty-seven eyes of 42 patients with perimetric glaucoma were age-matched with 27 normal eyes of 27 patients. All patients underwent Doppler Fourier-domain optical coherence tomography to measure retinal blood flow and standard glaucoma evaluation with visual field testing and quantitative structural imaging. Linear regression analysis was performed to analyze the relationship among visual field, blood flow, and structure, after all variables were converted to logarithmic decibel scale. RESULTS: Retinal blood flow was reduced in glaucoma eyes compared to normal eyes (P < 0.001). Visual field loss was correlated with both reduced retinal blood flow and structural loss of rim area and retinal nerve fiber layer (RNFL). There was no correlation or paradoxical correlation between blood flow and structure. Multivariate regression analysis revealed that reduced blood flow and structural loss are independent predictors of visual field loss. Each dB decrease in blood flow was associated with at least 1.62 dB loss in mean deviation (P ≤ 0.001), whereas each dB decrease in rim area and RNFL was associated with 1.15 dB and 2.56 dB loss in mean deviation, respectively (P ≤ 0.03). CONCLUSIONS: There is a close link between reduced retinal blood flow and visual field loss in glaucoma that is largely independent of structural loss. Further studies are needed to elucidate the causes of the vascular dysfunction and potential avenues for therapeutic intervention. Blood flow measurement may be useful as an independent assessment of glaucoma severity.

Regional practice patterns for retinal detachment repair in the United States.

PURPOSE: To determine if there are variations in regional practice patterns for retinal detachment repair in the United States. DESIGN: Retrospective, noninterventional, cross-sectional study. METHODS: Year 2009 Medicare fee-for-service claims for retinal detachment repair were aggregated in 4 geographic regions and evaluated. The relative preference for retinal detachment repair by pars plana vitrectomy, scleral buckling, and pneumatic retinopexy was analyzed. RESULTS: The Midwest demonstrated a greater preference for scleral buckling compared to all other regions (P < .01) and lower preference for pars plana vitrectomy relative to the South and West (P ≤ .02). The Northeast demonstrated a greater preference for pneumatic retinopexy when compared to all other regions (P < .01). The Northeast also revealed a trend toward a lower preference for pars plana vitrectomy compared to the West and South (P ≤ .08). CONCLUSION: There are statistically significant variations in regional practice patterns for retinal detachment repair. The West, despite its historical association with pneumatic retinopexy, did not demonstrate a greater preference for the surgical technique.

Autofluorescence imaging and spectral-domain optical coherence tomography in incomplete congenital stationary night blindness and comparison with retinitis pigmentosa.

PURPOSE: To test the hypothesis that the evaluation of retinal structure can have diagnostic value in differentiating between incomplete congenital stationary night blindness (CSNB2) and retinitis pigmentosa (RP). To compare retinal thickness differences between patients with CSNB2 and myopic controls. DESIGN: Prospective cross-sectional study. METHODS: Ten eyes of 5 patients diagnosed with CSNB2 (4 X-linked recessive, 1 autosomal recessive) and 6 eyes of 3 patients with RP (2 autosomal dominant, 1 autosomal recessive) were evaluated with spectral-domain optical coherence tomography (SD OCT) and fundus autofluorescence (FAF). Diagnoses of CSNB2 and RP were confirmed by full-field electroretinography (ERG). Manual segmentation of retinal layers, aided by a computer program, was performed by 2 professional segmenters on SD OCT images of all CSNB2 patients and 4 age-similar, normal myopic controls. Seven patients were screened for mutations with congenital stationary night blindness and RP genotyping arrays. RESULTS: Patients with CSNB2 had specific findings on SD OCT and FAF that were distinct from those found in RP. CSNB2 patients showed qualitatively normal SD OCT results with preserved photoreceptor inner segment/outer segment junction, whereas this junction was lost in RP patients. In addition, CSNB2 patients had normal FAF images, whereas patients with RP demonstrated a ring of increased autofluorescence around the macula. On SD OCT segmentation, the inner and outer retinal layers of both X-linked recessive and autosomal recessive CSNB2 patients were thinner compared with those of normal myopic controls, with means generally outside of normal 95% confidence intervals. The only layers that demonstrated similar thickness between CSNB2 patients and the controls were the retinal nerve fiber layer and, temporal to the fovea, the combined outer segment layer and retinal pigment epithelium. A proband and his 2 affected brothers from a family segregating X-linked recessive CSNB2 had a mutation, p.R614X, in the gene encoding calcium channel, α 1F subunit. CONCLUSIONS: CSNB2 patients (X-linked recessive and autosomal recessive) had significantly thinner retinas than myopic controls. However, they demonstrated qualitatively normal SD OCT and FAF images, and therefore can be differentiated from RP patients with these techniques. Although ERG testing remains the gold standard for the diagnosis of these conditions, FAF and SD OCT systems are more widely available to community ophthalmologists, offer shorter acquisition times, and, unlike ERG, can be performed on the same day as the initial clinic visit. Therefore, as a supplement to ERG and genetic testing, we advocate the use of FAF and SD OCT in the examination of patients with CSNB2 and RP.

Development of subretinal fibrosis after anti-VEGF treatment in neovascular age-related macular degeneration.

BACKGROUND AND OBJECTIVE: to describe the development or progression of subfoveal fibrosis after anti-vascular endothelial growth factor (VEGF) therapy in the absence of significant subfoveal hemorrhage in neovascular age-related macular degeneration. PATIENTS AND METHODS: retrospective case series. RESULTS: seven eyes of seven patients with neovascular age-related macular degeneration developed subfoveal fibrosis after anti-VEGF therapy in the absence of significant subfoveal hemorrhage. Five of seven patients experienced vision loss of 0.3 logarithm of the minimum angle of resolution units or greater. CONCLUSION: subfoveal fibrosis may develop or progress in neovascular age-related macular degeneration despite the absence of significant subfoveal hemorrhage and treatment with anti-VEGF. Development of anti-fibrotic therapeutics may be beneficial in reducing the incidence of subretinal fibrosis.

Combined arteriovenous sheathotomy and intraoperative intravitreal triamcinolone acetonide for branch retinal vein occlusion.

PURPOSE: To describe the treatment of macular oedema secondary to branch retinal vein occlusion (BRVO) with concomitant pars plana vitrectomy/arteriovenous sheathotomy and intraoperative intravitreal triamcinolone acetonide. METHODS: Retrospective case series. RESULTS: Four eyes of four patients were identified. Patients improved from a mean best-corrected visual acuity of 20/124 at baseline to 20/122 at month 1, 20/83 at month 3, 20/74 at month 6, 20/59 at month 9 and 20/44 at month 12 (p = 0.01). All patients demonstrated improvement in visual acuity and macular oedema on fluorescein angiography and/or optical coherence tomography (OCT). CONCLUSION: For patients with persistent macular oedema due to BRVO refractory to pharmacotherapy and/or laser photocoagulation, concomitant pars plana vitrectomy with arteriovenous sheathotomy and intravitreal triamcinolone may improve best-corrected acuity and reduce macular oedema on fluorescein angiography and OCT.

Fundus autofluorescence and optical coherence tomography of congenital grouped albinotic spots.

PURPOSE: The purpose of this study was to describe the findings of fundus autofluores-cence (FAF) and optical coherence tomography in a series of patients with congenital grouped albinotic spots. METHODS: Three eyes of three patients with congenital grouped albinotic spots were evaluated with FAF and optical coherence tomography imaging to evaluate the nature of the albinotic spots. RESULTS: In all three eyes with congenital grouped albinotic spots, FAF imaging showed autofluorescent spots corresponding to the albinotic spots seen on stereo biomicroscopy. One eye also had additional spots detected on FAF imaging that were not visible on stereo biomicroscopy or color fundus photographs. Fundus autofluorescence imaging of the spots showed decreased general autofluorescence and decreased peripheral autofluorescence surrounding central areas of retained or increased autofluorescence. Optical coherence tomography showed a disruption in signal from the hyperreflective layer corresponding to the inner and outer segment junction and increased signal backscattering from the choroid in the area of the spots. Fluorescein angiography showed early and stable hyperfluorescence of the spots without leakage. CONCLUSION: In this case series, FAF showed decreased autofluorescence of the spots consistent with focal retinal pigment epithelium atrophy or abnormal material blocking normal autofluorescence and areas of increased autofluorescence suggesting retinal pigment epithelium dysfunction. The findings of optical coherence tomography and fluorescein angiography suggest photoreceptor and retinal pigment epithelium layer abnormalities. Fundus autofluorescence and optical coherence tomography are useful noninvasive diagnostic adjuncts that can aid in the diagnosis of congenital grouped albinotic spots, help determine extent of disease, and contribute to our understanding of its pathophysiology.

Acute orbitocranial inflammation following radioimmunotherapy for non-Hodgkin lymphoma.

Radioimmunotherapy with yttrium-90-ibritumomab tiuxetan may result in hemorrhagic tumor necrosis with acute orbital and intracranial inflammation.

Fundus autofluorescence, optical coherence tomography, and electroretinogram findings in choroidal sclerosis.

PURPOSE: The purpose of this study was to describe fundus autofluorescence (FAF), optical coherence tomography, and electroretinogram findings in choroidal sclerosis. METHODS: This is a retrospective case series. Eight eyes of four patients with choroidal sclerosis were evaluated with FAF, optical coherence tomography, and electroretinogram testing. RESULTS: In all eight eyes, FAF imaging showed hypofluorescent placoid lesions corresponding to areas of chorioretinal atrophy seen on stereo biomicroscopy. Prominent hyperfluorescent linear markings underlying regions of atrophic disease were observed in all eyes, likely representative of normal choroidal vessel autofluorescence. In two eyes, FAF showed punctate hypofluorescent lesions in the fovea that were not visualized on biomicroscopy. In one eye, FAF identified a central island of preserved retinal pigment epithelium that was not realized on ophthalmoscopic examination. Optical coherence imaging was significant for loss of choroidal fine tubular structures, retinal pigment epithelium, and outer nuclear layer in regions of chorioretinal atrophy. Full-field electroretinogram testing showed generalized rod-cone dysfunction in all patients with a lower B- to A-wave ratio in two patients. CONCLUSION: Fundus autofluorescence and optical coherence tomography are nonin-vasive diagnostic adjuncts that can aid in the diagnosis of choroidal sclerosis. Fundus autofluorescence may be a more sensitive marker of disease extent and progression than clinical examination alone. Electroretinogram testing can result in an electronegative maximal response.

Peripapillary atrophy in Stargardt disease.

OBJECTIVE: To demonstrate that Stargardt disease (STGD) can present with peripapillary atrophy. METHODS: Retrospective case series. The medical records of 150 consecutive patients (300 eyes) were reviewed retrospectively from a STGD database from January 1999 to May 2007 at Columbia University's Harkness Eye Institute. STGD patients demonstrating peripapillary atrophy were identified. RESULTS: Three of 150 cases of STGD (2.0%) demonstrated peripapillary atrophy. Case 1 revealed peripapillary and central atrophy with heterozygous ABCA4 mutations P1380L and IVS40 + 5G>A. Case 2 demonstrated atrophic fleck lesions involving the peripapillary region and central atrophy with homozygous ABCA4 mutations P1380L and P1380L. Case 3 revealed bilateral central atrophy and pisciform fleck atrophy involving the peripapillary, macular, and peripheral regions with ABCA4 mutations P1380L and R2030Q. Overall, ABCA4 mutation P1380L was noted in 13 cases (8.7%), IVS40 + 5G>A in 6 cases (4.0%), and R2030Q in 1 case (0.7%). The remaining cases shared one common STGD mutation with Case 1, 2, and 3 (P1380L or IVS40 + 5G>A) and demonstrated classic STGD findings of central atrophy and varying presence of peripheral flecks without peripapillary lesions. CONCLUSION: STGD can present with peripapillary atrophy. This relatively uncommon phenotype may arise from specific combinations of STGD ABCA4 mutations rather than single mutations.

Safety and efficacy assessment of chimeric ribozyme to proliferating cell nuclear antigen to prevent recurrence of proliferative vitreoretinopathy.

OBJECTIVE: To determine the safety and efficacy of VIT100 (Immusol, Inc, San Diego, California), a ribozyme to proliferating cell nuclear antigen, in preventing recurrent proliferative vitreoretinopathy (PVR) in patients with established PVR who undergo vitrectomy for retinal reattachment repair. METHODS: A multicenter, double-masked, placebo-controlled, randomized clinical trial. One hundred seventy-five eyes from 175 patients with grade C or worse PVR were randomly assigned to receive high-dose VIT100, low-dose VIT100, or placebo by intravitreal injection at the conclusion of retinal reattachment surgery. MAIN OUTCOME MEASURES: The primary efficacy end point was recurrent retinal detachment secondary to PVR. The secondary end point was recurrent retinal detachment due to any cause. RESULTS: One hundred fifty-four patients completed the study. Forty-one patients (27%) developed recurrent retinal detachment due to PVR by 24 weeks, including 18 patients (33%) in the group receiving 0.75 mg, 13 patients (24%) in the group receiving 0.15 mg, and 10 patients (22%) in the placebo group. There was no statistically significant difference in patients reaching this end point by 24 weeks (P = .37). Ancillary statistical analyses are reported. CONCLUSIONS: VIT100 was not effective in preventing PVR recurrence in patients with established grade C or worse PVR. APPLICATION TO CLINICAL PRACTICE: To our knowledge, this is the most recent, meticulously designed clinical trial in PVR.

Optic pit maculopathy after laser-assisted in situ keratomileusis.

CASE REPORT: Optic disc pit is an embryological malformation of the optic nerve that occurs in less than one in 10,000 people. It is 10%-15% bilateral, and 25% to 70% of patients develop a neurosensory macular detachment within the 2nd to 4th decade. COMMENTS: We report a case of unilateral optic disc pit maculopathy 2 months after laser-assisted in situ keratomileusis (LASIK) revision.

Diabetic vitrectomy: influence of lens status upon anatomic and visual outcomes.

OBJECTIVE: To determine the effect of lens status upon the anatomic and visual results in primary diabetic vitrectomy. DESIGN: Retrospective, comparative, consecutive case series. PARTICIPANTS: One hundred two eyes of 85 patients with proliferative diabetic retinopathy and its complications that underwent primary vitrectomy. METHODS: The eyes that remained phakic after vitrectomy were compared with the eyes that were either aphakic or pseudophakic (nonphakic) postoperatively. MAIN OUTCOME MEASURES: Intraoperative and postoperative complications, vitreoretinal reoperation rate, and ultimate anatomic and visual success with at least 6 months' follow-up. RESULTS: Preoperatively, 72 eyes were phakic, and 30 were aphakic (n = 1) or pseudophakic (n = 29). During vitrectomy, 1 eye underwent lensectomy and 12 eyes underwent phacoemulsification with lens implantation. Postoperatively, 59 eyes were phakic and 43 eyes were nonphakic. The vitreoretinal reoperation rate was significantly higher (P = 0.04) for the phakic group (28.8%) than for the nonphakic group (11.6%). Rubeosis iridis developed in 3 phakic eyes and no nonphakic eyes (P = 0.26). Intraoperative complications were similar in the phakic and nonphakic groups (P = 0.40). Postoperative complications such as rhegmatogenous retinal detachment (P = 0.39), nonclearing vitreous hemorrhage (P = 0.07), and anterior chamber complications (P = 0.60) were also similar. Visual acuity improved by at least 0.2 logarithm of the minimum angle of resolution units in 76.2% of the phakic eyes and 86.0% of the nonphakic eyes (P = 0.22). CONCLUSIONS: Eyes that were phakic after primary diabetic vitrectomy had a significantly higher subsequent vitreoretinal reoperation rate when compared with nonphakic eyes, suggesting that diabetic eyes are less likely to require additional vitreoretinal surgery if they are rendered nonphakic before or during vitrectomy.

Optical coherence tomography in asteroid hyalosis.

PURPOSE: To demonstrate the clinical utility of optical coherence tomography (OCT) in diagnosing macular structural abnormalities in patients with asteroid hyalosis. METHODS: Case series. RESULTS: Seven eyes of seven patients underwent OCT due to inadequate funduscopic visualization secondary to asteroid hyalosis. Fluorescein angiography and B-scan ultrasonography were conducted for two patients but failed to provide diagnostic clarity. OCT provided definitive anatomical diagnoses that included macular epiretinal membrane, macular hole, traction retinal detachment, cystoid macular edema, and drusen. On the basis of OCT-assisted diagnoses, three patients elected to undergo surgical intervention. CONCLUSION: OCT can be critical to diagnose macular conditions when retinal visualization is limited by asteroid hyalosis.

Representation of ophthalmology concepts by electronic systems: intercoder agreement among physicians using controlled terminologies.

OBJECTIVE: To assess intercoder agreement for ophthalmology concepts by 3 physician coders using 5 controlled terminologies (International Classification of Diseases 9, Clinical Modification [ICD9CM]; Current Procedural Terminology, fourth edition; Logical Observation Identifiers, Names, and Codes [LOINC]; Systematized Nomenclature of Medicine, Clinical Terms [SNOMED-CT]; and Medical Entities Dictionary). DESIGN: Noncomparative case series. PARTICIPANTS: Five complete ophthalmology case presentations selected from a publicly available journal. METHODS: Each case was parsed into discrete concepts. Electronic or paper browsers were used independently by 3 physician coders to assign a code for every concept in each terminology. A match score representing adequacy of assignment for each concept was assigned on a 3-point scale (0, no match; 1, partial match; 2, complete match). For every concept, the level of intercoder agreement was determined by 2 methods: (1) based on exact code matching with assignment of complete agreement when all coders assigned the same code, partial agreement when 2 coders assigned the same code, and no agreement when all coders assigned different codes, and (2) based on manual review for semantic equivalence of all assigned codes by an independent ophthalmologist to classify intercoder agreement for each concept as complete agreement, partial agreement, or no agreement. Subsequently, intercoder agreement was calculated in the same manner for the subset of concepts judged to have adequate coverage by each terminology, based on receiving a match score of 2 by at least 2 of the 3 coders. MAIN OUTCOME MEASURES: Intercoder agreement in each controlled terminology: complete, partial, or none. RESULTS: Cases were parsed into 242 unique concepts. When all concepts were analyzed by manual review, the proportion of complete intercoder agreement ranged from 12% (LOINC) to 44% (SNOMED-CT), and the difference in intercoder agreement between LOINC and all other terminologies was statistically significant (P<0.004). When only concepts with adequate terminology were analyzed by manual review, the proportion of complete intercoder agreement ranged from 33% (LOINC) to 64% (ICD9CM), and there were no statistically significant differences in intercoder agreement among any pairs of terminologies. CONCLUSIONS: The level of intercoder agreement for ophthalmic concepts in existing controlled medical terminologies is imperfect. Intercoder reproducibility is essential for accurate and consistent electronic representation of medical data.

Reliability of SNOMED-CT coding by three physicians using two terminology browsers.

SNOMED-CT has been promoted as a reference terminology for electronic health record (EHR) systems. Many important EHR functions are based on the assumption that medical concepts will be coded consistently by different users. This study is designed to measure agreement among three physicians using two SNOMED-CT terminology browsers to encode 242 concepts from five ophthalmology case presentations in a publicly-available clinical journal. Inter-coder reliability, based on exact coding match by each physician, was 44% using one browser and 53% using the other. Intra-coder reliability testing revealed that a different SNOMED-CT code was obtained up to 55% of the time when the two browsers were used by one user to encode the same concept. These results suggest that the reliability of SNOMED-CT coding is imperfect, and may be a function of browsing methodology. A combination of physician training, terminology refinement, and browser improvement may help increase the reproducibility of SNOMED-CT coding.