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PURPOSE: Comparison of safety and clinical results of Descemet membrane endothelial keratoplasty (DMEK) in topical, peribulbar, or general anesthesia. METHODS: Retrospective, post hoc matched study of 346 patients who received DMEK surgery with different types of anesthesia (n = 54 topical, n = 137 peribulbar, n = 155 general anesthesia). Outcome criteria were intraoperative complications, endothelial cell count (ECC), central corneal thickness (CCT) and graft rejection rate, rebubbling rate, and visual acuity (VA). Mean follow-up time was 9.4 ± 2.8 months. RESULTS: The group with topical anesthesia showed intraoperative difficulties such as vitreous pressure (p = 0.01) and difficult graft unfolding (p = 0.4), possibly leading to a higher rebubbling rate (p = 0.03) and therefore graft failure (p = 0.39). However, rebubbling and graft failure occurred more often when the graft preparation was more difficult (p = 0.2, p = 0.13, respectively), which was independent of anesthesia. All three groups achieved comparable functional results regarding VA, ECC, and CCT after 6 months. CONCLUSION: DMEK under topical anesthesia is feasible and shows comparable final visual outcomes but should be limited to selected cooperative patients and performed by experienced surgeons due to the potential for increased intraoperative challenges.
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PURPOSE: Congenital aniridia is a severe malformation of almost all eye segments. In addition, endocrinological, metabolic, and central nervous systems diseases may be present. In order to develop better treatment options for this rare disease, an aniridia center must be established. The purpose of this work is to summarize ophthalmic findings of aniridia subjects examined at the Department of Ophthalmology, Saarland University Medical Center in Homburg. METHODS: Our retrospective single-center study included patients who underwent a comprehensive ophthalmic examination through the head of the KiOLoN ("Kinderophthalmologie", Orthoptics, Low Vision and Neuroophthalmology) Unit of the department between June 2003 and January 2022. Data at the first examination time point have been included. RESULTS: Of 286 subjects, 556 eyes of (20.1 ± 20.1 years; 45.5% males) were included. There was nystagmus in 518 (93.7%) eyes, and strabismus in 327 (58.8%) eyes. There were 436 (78.4%) eyes with age-appropriate axial length, 104 (18.7%) eyes with microphthalmos, and 13 (2.3%) eyes with buphthalmos. There was iris malformation with atypical coloboma in 34 eyes (6.1%), more than 6 clock hours of iris remnants in 61 eyes (10.9%), less than 6 clock hours of iris remnants in 96 eyes (17.2%), and complete aniridia in 320 (57.5%) eyes. The patients were graded according to the following aniridia-associated keratopathy (AAK) stages: Stage 0 (96 eyes [17.2%], no keratopathy), Stage 1 (178 eyes [32.0%]), Stage 2 (107 eyes [19.2%]), Stage 3 (67 eyes [12.0%]), Stage 4 (62 eyes [11.1%]), Stage 5 (45 eyes [8.0%]). There was secondary glaucoma in 307 (55.5%), macular hypoplasia in 395 (71.4%), and congenital optic nerve head pathology in 223 (40.3%) eyes. The iris malformation type was significantly positively correlated with AAK stage, lens properties, presence of glaucoma, congenital macular, and optic nerve head properties (p < 0.001 for all), while complete aniridia showed the most complications. CONCLUSIONS: At the Homburg Aniridia Center, the most common ophthalmic signs in congenital aniridia were AAK, iris malformation, cataract, and macular hypoplasia. The iris malformation type may indicate future expression of AAK, cataract, and glaucoma development and it is correlated with a congenital optic nerve head and macular pathology. Our registry will support further detailed longitudinal analysis of ophthalmic and systemic diseases of aniridia subjects during long-term follow-up.
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Aniridia , Catarata , Doenças da Córnea , Glaucoma , Masculino , Humanos , Idoso de 80 Anos ou mais , Feminino , Estudos Transversais , Estudos Retrospectivos , Aniridia/diagnóstico , Aniridia/epidemiologia , Catarata/complicações , Glaucoma/complicações , Transtornos da Visão/diagnóstico , Transtornos da Visão/epidemiologia , Transtornos da Visão/etiologiaRESUMO
BACKGROUND: Congenital aniridia is a severe malformation of almost all eye segments. Aniridia-associated keratopathy (AAK) and secondary glaucoma, which occur in more than 50% of affected individuals, are typically progressive and pose a high risk of blindness for patients with congenital aniridia. Our aim was to investigate the effect of glaucoma treatment on AAK in patients of the Homburg Aniridia Center. METHODS: Our retrospective monocentric study included patients who underwent a comprehensive ophthalmological examination at the Homburg Aniridia Center between June 2003 and January 2022. RESULTS: There were 556 eyes of 286 subjects (20.1 ± 20.1 years; 45.5% males) included. In 307 (55.2%) eyes of 163 subjects (27.5 ± 16.3 years; 43.1% males), glaucoma was present at the time of examination. The mean intraocular pressure in the glaucoma group was 19.0 mmHg (± 8.0), while in the non-glaucoma group, it was 14.1 mmHg (± 3.6) (p < 0.001). In the glaucoma group, 68 patients used antiglaucomatous topical monotherapy, 51 patients used 2 agents, 41 patients used 3 agents, 7 patients used quadruple therapy, and 140 did not use topical therapy (e.g., after pressure-lowering surgery, pain-free end-stage glaucoma, or incompliance). Patients were classified according to the following stages of AAK: Stage 0 (96 eyes [17.2%], no keratopathy), Stage 1 (178 eyes [32.0%]), Stage 2 (107 eyes [19.2%]), Stage 3 (67 eyes [12.0%]), Stage 4 (62 eyes [11.1%]), Stage 5 (45 eyes [8.0%]). The mean stage of AAK was 1.4 (1.2â-â1.5) in the group without eye drops, 1.9 (1.5â-â2.2) in the group with monotherapy, 1.8 (1.5â-â2.1) in the group with 2 drugs, 1.9 (1.5â-â2.2) in the group with 3 drugs, 3.4 (2.3â-â4.6) in the group with 4 drugs, and 3.3 (3.1â-â3.6) after antiglaucomatous surgery. The stage of AAK was significantly positively correlated with the number of pressure-lowering eye drops (p < 0.05) and prior pressure-lowering surgery (p < 0.05). Prostaglandin analogues were not correlated with a higher AAK stage compared to the other drug groups. CONCLUSIONS: At the Homburg Aniridia Center, patients using topical antiglaucomatous quadruple therapy or who had previously undergone antiglaucomatous surgery had by far the highest AAK stage. The different drug groups had no influence on the AAK stage.
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PURPOSE: The aim of this case series was to investigate the clinical course of patients with optic pit maculopathy. METHODS: The medical records of all patients diagnosed with optic pit maculopathy in the past 10 years were reviewed. Optic pit maculopathy was diagnosed when localized intraretinal or/and subretinal fluid spread from the optic nerve to the macula. Outcome measures included changes in best corrected visual acuity (BCVA), central retinal thickness (RT) as well as nasal parafoveal and perifoveal RT. RESULTS: An optic disc pit was detected in 18 patients (9 female, 9 male, mean age: 33⯱ 23 years). Retinal fluid accumulation was present in 6 (33.3%) of the patients (1 intraretinal, 1 subretinal, 4 intraretinal and subretinal). Pars plana vitrectomy with removal of peripapillary vitreous traction and peeling of the internal limiting membrane (ILM) was indicated in 5 patients and was performed in 4 patients. One patient underwent nanopulse laser treatment instead. The patients with optic pit maculopathy were 47⯱ 16 years old. In this group of patients, mean BCVA (decimal) improved from 0.3⯱ 0.2 before treatment to 0.5⯱ 0.2 3 months after treatment (pâ¯= 0.03). Visual acuity improved in all patients with optic disc pit maculopathy after pars plana vitrectomy. The mean central RT decreased from 796⯱ 214 before treatment to 324⯱ 57 3 months after treatment (pâ¯= 0.005). The mean nasal parafoveal RT decreased from 683⯱ 87 before treatment to 372⯱ 41 (pâ¯= 0.0003) and the mean nasal perifoveal RT decreased from 547⯱ 89 before treatment to 360⯱ 48 (pâ¯= 0.007). A completely dry macula was achieved in 4 eyes after a mean follow-up of 3 months. At long-term follow-up (2.5⯱ 1.2 years), no recurrence occurred in the vitrectomized eyes. CONCLUSION: This case series showed that more than one third of the patients had optic pit maculopathy presumably caused by disruption of the Kuhnt intermediate tissue. Interventional treatment was indicated in all cases, of which 4 were surgically treated and resulted in significant improvement of function and anatomical retinal structures.
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Anormalidades do Olho , Degeneração Macular , Doenças Retinianas , Humanos , Masculino , Feminino , Criança , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Incidência , Tomografia de Coerência Óptica , Doenças Retinianas/diagnóstico , Anormalidades do Olho/cirurgia , Progressão da DoençaRESUMO
INTRODUCTION: Congenital aniridia is a rare panocular disease that affects almost all eye structures leading in most patients to reduced visual acuity. Ophthalmological signs include aniridia-associated keratopathy, secondary glaucoma, cataract, macular and optic nerve head hypoplasia, nystagmus. Although the term aniridia-associated keratopathy has long been used in the literature, various staging proposals have been described. OBJECTIVE: To analyze aniridia-associated keratopathy stages, using available literature classifications, in patients with aniridia in Hungary. PATIENTS AND METHODS: We examined 65 eyes of 33 patients with congenital aniridia (age: 25.69 ± 17.49 [5-59] years, 17 females [51.51%]). We recorded the corneal status by slit-lamp examination and classified the corneal abnormalities according to the Mackman, Mayer, López-García and Lagali staging. RESULTS: According to Mackman's classification, 8 eyes (12.3%) were in stage 0, 0 eye in stage 1A, 38 eyes (58.46%) in stage 1B and 19 eyes (29.23%) in stage 2. According to Mayer, stage I included 8 eyes (12.3%), stage II 38 eyes (58.46%), stage III 5 eyes (7.7%), stage IV 7 eyes (10.77%) and stage V 7 eyes (10.77%). In López-García's classification, 8 eyes (12.3%) could not be grouped, 20 eyes (30.77%) were in stage 1, 18 eyes (27.7%) in stage 2 and 19 eyes (29.3%) in stage 3. Lagali's classification included 8 eyes (12.3%) in stage 0, 20 eyes (30.77%) in stage 1, 18 eyes (27.7%) in stage 2, 5 eyes (7.7%) in stage 3 and 14 eyes (21.54%) in stage 4. CONCLUSION: We recommend using Lagali's staging scheme for aniridia-associated keratoptahy due to its ease of use, detailed progression assessment, and treatment planning. In stage 1 according to Lagali, blood vessels cross the limbus by up to 1 mm, in stage 2 the central 2-3 mm of the corneal area is spared of blood vessels. When the blood vessels reach the center of the cornea, it is stage 3, followed by opaque, uneven corneal pannus in stage 4. Orv Hetil. 2023; 164(27): 1063-1069.
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Aniridia , Catarata , Doenças da Córnea , Feminino , Humanos , Criança , Adolescente , Adulto Jovem , Adulto , Doenças da Córnea/etiologia , Aniridia/complicações , Aniridia/diagnóstico , Córnea , Transtornos da VisãoRESUMO
PURPOSE: To assess various potential factors on human limbal epithelial cell (LEC) outgrowth in vitro using corneal donor tissue following long-term storage (organ culture) and a stepwise linear regression algorithm. METHODS: Of 215 donors, 304 corneoscleral rings were used for our experiments. For digestion of the limbal tissue and isolation of the limbal epithelial cells, the tissue pieces were incubated with 4.0 mg/mL collagenase A at 37â°C with 95% relative humidity and a 5% CO2 atmosphere overnight. Thereafter, limbal epithelial cells were separated from limbal keratocytes using a 20-µm CellTricks filter. The separated human LECs were cultured in keratinocyte serum-free medium medium, 1% penicillin/streptomycin (P/S), 0.02% epidermal growth factor (EGF), and 0.3% bovine pituitary extract (BPE). The potential effect of donor age (covariate), postmortem time (covariate), medium time (covariate), size of the used corneoscleral ring (360°, 270°180°, 120°, 90°, less than 90°) (covariate), endothelial cell density (ECD) (covariate), gender (factor), number of culture medium changes during organ culture (factor), and origin of the donor (donating institution and storing institution, factor) on the limbal epithelial cell outgrowth was analyzed with a stepwise linear regression algorithm. RESULTS: The rate of successful human LEC outgrowth was 37.5%. From the stepwise linear regression algorithm, we found out that the relevant influencing parameters on the LEC growth were intercept (p < 0.001), donor age (p = 0.002), number of culture medium changes during organ culture (p < 0.001), total medium time (p = 0.181), and size of the used corneoscleral ring (p = 0.007), as well as medium timeâ×âsize of the corneoscleral ring (p = 0.007). CONCLUSIONS: The success of LEC outgrowth increases with lower donor age, lower number of organ culture medium changes during storage, shorter medium time in organ culture, and smaller corneoscleral ring size. Our stepwise linear regression algorithm may help us in optimizing LEC cultures in vitro.
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PURPOSE: To analyze endothelial cell density (ECD) and central corneal thickness (CCT) following penetrating keratoplasty (PKP) in Acanthamoeba keratitis (AK) patients. PATIENTS AND METHODS: In this retrospective, clinical, single-center, cross-sectional, observational study, patients were enrolled who underwent PKP at the Department of Ophthalmology of Saarland University Medical Center, Homburg/Saar, Germany between May 2008 and December 2016 with the diagnosis of AK. In all, 33 eyes of 33 patients (14 males, 42%) were enrolled; their mean age at the time of surgery was 39.5 ± 14.3 years. Postoperatively, AK patients received topical polyhexamethylene biguanide, propamidine isethionate, neomycin sulphate/gramicidin/polymixin B sulfate, and prednisolone acetate eye drops (5 ×/day each), and the topical treatment was tapered sequentially with 1 drop every 6 weeks over 6 months. CCT was recorded using Pentacam HR Scheimpflug tomography and ECD with the EM-3000 specular microscope before surgery and 3 and 6 months after surgery as well as after the first and second (complete) suture removal. RESULTS: ECD tended to decrease significantly from the time point before surgery (2232 ± 296 cells/mm2) to the time point 3 months after surgery (1914 ± 164 cells/mm2; p = 0.080) and to the time point after the first suture removal (1886 ± 557 cells/mm2; p = 0.066) and decrease significantly to the time point after the second suture removal (1650 ± 446 cells/mm2; p = 0.028). CCT did not change significantly over the analyzed time period (p ≥ 0.475). CONCLUSION: In AK, endothelial cell loss does not seem to be accelerated following PKP, despite the postoperative use of diamidine and biguanide. A subsequent prospective comparative study should confirm our retrospective longitudinal analysis.
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Ceratite por Acanthamoeba , Ceratoplastia Penetrante , Ceratite por Acanthamoeba/diagnóstico , Ceratite por Acanthamoeba/cirurgia , Estudos Transversais , Células Endoteliais , Humanos , Ceratoplastia Penetrante/efeitos adversos , Ceratoplastia Penetrante/métodos , Masculino , Estudos Prospectivos , Estudos RetrospectivosRESUMO
Congenital PAX6-aniridia is a rare panocular disease resulting from limbal stem cell deficiency. In PAX6-aniridia, the downregulation of the retinol-metabolizing enzymes ADH7 (All-trans-retinol dehydrogenase 7) and ALDH1A1/A3 (Retinal dehydrogenase 1, Aldehyde dehydrogenase family 1 member A3) have been described in limbal epithelial cells (LECs) and conjunctival epithelial cells. The aim of this study was to identify the role of retinol derivates in the differentiation of human LEC and its potential impact on aniridia-associated keratopathy development. Human LEC were isolated from healthy donor corneas and were cultured with retinol, retinoic acid, or pan-retinoic acid receptor antagonist (AGN 193109) acting on RARα, ß, γ (NR1B1, NR1B2 NR1B3) or were cultured with pan-retinoid X receptor antagonist (UVI 3003) acting on RXR α, ß, γ (retinoid X receptor, NR2B1, NR2B2, BR2B3). Using qPCR, differentiation marker and retinoid-/fatty acid metabolism-related mRNA expression was analysed. DSG1 (Desmoglein 1), KRT3 (Keratin 3), and SPINK7 (Serine Peptidase Inhibitor Kazal Type 7) mRNA expression was downregulated when retinoid derivates were used. AGN 193109 treatment led to the upregulation of ADH7, KRT3, and DSG1 mRNA expression and to the downregulation of KRT12 (Keratin 12) and KRT19 (Keratin 19) mRNA expression. Retinol and all-trans retinoic acid affect some transcripts of corneal LEC in a similar way to what has been observed in the LEC of PAX6-aniridia patients with the altered expression of differentiation markers. An elevated concentration of retinol derivatives in LEC or an altered response to retinoids may contribute to this pattern. These initial findings help to explain ocular surface epithelia differentiation disorders in PAX6-aniridia and should be investigated in patient cells or in cell models in the future in more detail.
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Regulação para Baixo , Tretinoína , Aniridia , Doenças da CórneaRESUMO
Acanthamoeba keratitis is a "chameleon". It presents classically with greyish epithelial changes, perineuritis, superficial multifocal stromal infiltrates and ring infiltrate. In the presence of clinical signs, polymerase chain reaction, in vitro culture or histopathological examination have to be used to confirm the diagnosis. In vivo confocal microscopy is applied as an early non-invasive ad-hoc diagnostic method.
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Ceratite por Acanthamoeba , Cor , Humanos , Microscopia Intravital , Microscopia Confocal , Reação em Cadeia da PolimeraseAssuntos
Aniridia/genética , Doenças da Córnea/genética , Fator de Transcrição PAX6/genética , Adolescente , Adulto , Aniridia/diagnóstico , Criança , Pré-Escolar , Doenças da Córnea/diagnóstico , Análise Mutacional de DNA , Feminino , Humanos , Lactente , Masculino , Microscopia Confocal , Pessoa de Meia-Idade , Fenótipo , Tomografia de Coerência Óptica , Adulto JovemRESUMO
PURPOSE: To investigate corneal phenotype in aniridia-associated keratopathy (AAK) including its earliest manifestations, in relation to PAX6 mutational status. METHODS: 46 subjects (92 eyes) with congenital aniridia from a German registry were examined using slit lamp biomicroscopy, anterior segment optical coherence tomography, contact esthesiometry and in vivo confocal microscopy. Cytogenetic analysis was conducted by Sanger sequencing of PAX6 exons and/or MLPA analysis. Measured parameters included AAK grade, distance-corrected visual acuity (DCVA), central corneal thickness (CCT), corneal sensitivity, subbasal nerve density, mature dendritic cell (DC) density and corneal epithelial phenotype. RESULTS: 46 subjects (age range: 1-64 years) were examined, including 23 (50%) children under the age of 18. Five subjects (11.1%) with absent PAX6 coding mutation (non-PAX6 cases) had mild AAK (Grade 0-1) into the fourth decade of life and maintained corneal epithelial phenotype, greater subbasal nerve density (16.8â¯mm/mm2 vs. 3.58â¯mm/mm2, Pâ¯=â¯0.01) and better corneal sensitivity (41⯱â¯11â¯mm vs. 28⯱â¯12â¯mm, Pâ¯=â¯0.03) relative to those with PAX6 coding mutations. In five subjects, corneal endothelial cell density ranged from 3245 to 4399â¯cells/mm2. Independent of mutational status, an increased CCT, over tenfold increased mature DC density and reduced corneal sensitivity characterized all subjects. CONCLUSIONS: PAX6 coding mutations influence AAK phenotype and progression from the earliest stages of life. A minimal keratopathy present in 100% of congenital aniridia cases is independent of the specific mutation and consists of increased corneal thickness, reduced touch sensitivity, and increased ocular surface immune activity.
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Aniridia , Doenças da Córnea , Fator de Transcrição PAX6/genética , Adolescente , Adulto , Aniridia/complicações , Aniridia/genética , Criança , Pré-Escolar , Córnea , Doenças da Córnea/genética , Humanos , Lactente , Pessoa de Meia-Idade , Mutação , Fenótipo , Adulto JovemRESUMO
We analysed histologically two Acanthamoeba keratitis (AK) eyes with anterior and posterior segment inflammation and blindness. Two enucleated eyes of 2 patients (age 45 and 51y) with AK (PCR of epithelial abrasion positive) were analysed. Histological analysis was performed using hematoxylin-eosin, periodic acid-Schiff and Gömöri-methenamine silver staining. We could not observe Acanthamoeba trophozoites or cysts neither in the cornea nor in other ocular tissues. Meanwhile, we found uveitis, retinal vasculitis and scleritis in these eyes, due to the long-standing, recalcitrant AK. So in this stage of AK, systemic immune suppression may be necessary for a longer time period.
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BACKGROUND: More than 8.5 million Germans suffer from chronic diseases attributable to smoking. Education Against Tobacco (EAT) is a multinational network of medical students who volunteer for school-based prevention in the classroom setting, amongst other activities. EAT has been implemented in 28 medical schools in Germany and is present in 13 additional countries around the globe. A recent quasi-experimental study showed significant short-term smoking cessation effects on 11-to-15-year-old adolescents. OBJECTIVE: The aim of this study was to provide the first randomized long-term evaluation of the optimized 2014 EAT curriculum involving a photoaging software for its effectiveness in reducing the smoking prevalence among 11-to-15-year-old pupils in German secondary schools. METHODS: A randomized controlled trial was undertaken with 1504 adolescents from 9 German secondary schools, aged 11-15 years in grades 6-8, of which 718 (47.74%) were identifiable for the prospective sample at the 12-month follow-up. The experimental study design included measurements at baseline (t1), 6 months (t2), and 12 months postintervention (t3), via questionnaire. The study groups consisted of 40 randomized classes that received the standardized EAT intervention (two medical student-led interactive modules taking 120 minutes total) and 34 control classes within the same schools (no intervention). The primary endpoint was the difference in smoking prevalence from t1 to t3 in the control group versus the difference from t1 to t3 in the intervention group. The differences in smoking behavior (smoking onset, quitting) between the two groups, as well as gender-specific effects, were studied as secondary outcomes. RESULTS: None of the effects were significant due to a high loss-to-follow-up effect (52.26%, 786/1504). From baseline to the two follow-up time points, the prevalence of smoking increased from 3.1% to 5.2% to 7.2% in the control group and from 3.0% to 5.4% to 5.8% in the intervention group (number needed to treat [NNT]=68). Notable differences were observed between the groups for the female gender (4.2% to 9.5% for control vs 4.0% to 5.2% for intervention; NNT=24 for females vs NNT=207 for males), low educational background (7.3% to 12% for control vs 6.1% to 8.7% for intervention; NNT=30), and migrational background (students who claimed that at least one parent was not born in Germany) at the 12-month follow-up. The intervention appears to prevent smoking onset (NNT=63) but does not appear to initiate quitting. CONCLUSIONS: The intervention appears to prevent smoking, especially in females and students with a low educational background.
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Serviços de Saúde Escolar/estatística & dados numéricos , Instituições Acadêmicas/estatística & dados numéricos , Abandono do Hábito de Fumar/métodos , Prevenção do Hábito de Fumar/métodos , Fumar/psicologia , Estudantes de Medicina/psicologia , Adolescente , Criança , Feminino , Alemanha , Humanos , Masculino , Estudos Prospectivos , Projetos de Pesquisa , Fumar/epidemiologia , Inquéritos e Questionários , NicotianaRESUMO
BACKGROUND: Smoking is the largest preventable cause of morbidity and mortality in Brazil. Education Against Tobacco (EAT) is a large network of medical students in 13 countries who volunteer for school-based prevention in the classroom setting. A recent quasi-experimental EAT study conducted in Germany showed significant short-term smoking cessation effects on 11- to 15-year-old adolescents. OBJECTIVE: The aim of this study is both to describe and to provide the first randomized long-term evaluation of the EAT intervention involving a photoaging app for its effectiveness to reduce the smoking prevalence among 12- to 17-year-old pupils in Brazilian public schools. METHODS: A randomized controlled trial will be conducted among approximately 1500 adolescents aged 12 to 17 years in grades 7-11 of public secondary schools in Brazil. The prospective experimental study design includes measurements at baseline and at 6 and 12 months postintervention. The study groups will consist of randomized classes receiving the standardized EAT intervention (90 minutes of mentoring in a classroom setting) and control classes within the same schools (no intervention). The questionnaire measures smoking status, gender, social, and cultural aspects as well as predictors of smoking. Biochemical validation of smoking status is conducted via random carbon monoxide measurements. The primary end point is the difference of the change in smoking prevalence in the intervention group versus the difference in the control group at 12 months of follow-up. The differences in smoking behavior (smoking onset, quitting) between the 2 groups as well as effects on the different genders will be studied as secondary outcomes. RESULTS: The recruitment of schools, participating adolescents, and medical students was conducted from August 2016 until January 2017. The planned period of data collection is February 2017 until June 2018. Data analysis will follow in July 2018 and data presentation/publication will follow shortly thereafter. CONCLUSIONS: This is the first evaluative study of a medical student-delivered tobacco prevention program in Brazil and the first randomized trial on the long-term effectiveness of a school-based medical student-delivered tobacco prevention program in general. CLINICALTRIAL: ClinicalTrials.gov NCT02725021; https://clinicaltrials.gov/ct2/show/NCT02725021 (archived by WebCite at http://www.webcitation.org/6njy3nNml).