Pediatric keratoconus (KC) causes progressive deformation of the cornea of children and adolescents, leading to progressive loss of vision and need for rehabilitation(1). Its epidemiology is still poorly understood. However, the need for its reporting is now increased due to new treatments allowing halting of the disease and prevention of the worse outcomes such as the need for penetrating keratoplasty and its associated morbidity and high cost, irreversible loss of vision and amblyopia. There are few systematic reviews on keratoconus, even fewer on pediatric KC(2).Objectives: The authors objective was to perform a systematic review on pediatric KC epidemiology, discuss the studies reporting data on pediatric keratoconus (prevalence, incidence, age distribution) and current diagnostic and screening efforts. The scoping review methodology was favored due to it being the most adequate for summarizing findings from a body of knowledge that is heterogeneous in methods and disciplines (Tricco et al., 2018). The PRISMA-ScR methodology and checklists were used in the elaboration of the manuscript(3). Eligibility Criteria The inclusion criteria are: English language, publication between August 7th 1998 and August 7th 2019 (20 years), studies on the epidemiology of pediatric keratoconus. Sources of evidence The search strategy was performed in the PubMed-MEDLINE database and Cochrane Database of Systematic Reviews and included eight combinations of these MeSH terms: keratoconus; child; incidence; prevalence; pediatrics; adolescent; epidemiology. The included articles were in the English language, with available abstracts, published between August 7th 1998 and August 7th 1998 (20 years) in the PubMed-MEDLINE database. Charting Methods “A flowchart of the article selection process will be provided as per PRISMA-ScR recommendations.” The included studies will be charted in Excel 2019, in order to summarize research methodologies, describe the included populations and demographic characteristics. Expected Results The authors expect to systematically summarize the existing literature, report the methodology of the current epidemiological studies and describe the gathered information. Pediatric keratoconus (KC) is a disease of the eye which causes progressive deformation of the cornea of children and adolescents. KC is bilateral and asymmetric, and its progression may lead to acute corneal hydrops – corneal edema due to breaks in the corneal Descemet membrane with subsequent scarring of the cornea(4). Keratoconus is usually considered to be more severe in the pediatric population (5). Pediatric KC causes a shifting myopic and astigmatic refractive error. Uncorrected refractive error is of severe concern in children due to the possible development of amblyopia, which is an irreversible reduced vision due to inadequate development of the visual brain pathways(Wallace et al., 2007). Traditionally, mild pediatric KC treatment has been based on rehabilitation with glasses and contact lenses. However, severe cases with corneal opacities and highly irregular and curved corneas may require surgery such as intracorneal rings segments, penetrating keratoplasties or deep anterior lamellar keratoplasties(4,7–15). Penetrating keratoplasty (PK) is associated with high costs and brings some morbidity, including the need for reoperations, intraoperative complications, need for visual rehabilitation with glasses and contact lenses, close follow-up visits, and more severe complications such as infectious disease. Furthermore, PK is difficult to be performed in the young due to need of post-operative manipulation, eye rubbing tendencies, poor compliance, increased risk of rejection and increased inflammatory response(7,8,12,16–22). Pediatric KC’s epidemiology has gained importance, due to the possibility of alteration of KC’s natural history through corneal crosslinking(1,23,32,24–31). The development of corneal crosslinking allows for earlier intervention with a possible change in the course of the disease, allowing the prevention of complications and stabilization of corneal anatomy(19,22,32,38–43). In addition, corneal CXL appears to be a cost-effective treatment compared to conventional treatment with PK(44). CXL is based on the application of riboflavin and ultraviolet light on the cornea, which causes strengthening of the cornea due to increase of collagen crosslinks. Pediatric KC is a global healthcare concern and it may be more common than previously reported(19,22,32,38–43). Its epidemiology is still poorly understood, however it is fundamental to policy decisions regarding possible pediatric KC screening programs. Therefore, the authors objective is to conduct a systematic scoping review on pediatric KC: define the disease, describe the studies reporting epidemiological data (prevalence, incidence), its clinical features and screening programs. The authors found that due to the breadth of the purposed review and the significant knowledge gaps, a scoping review was the most appropriate tool to report the information. Methods: The scoping review methodology was favored due to it being the most adequate for summarizing findings from a body of knowledge that is heterogeneous in methods and disciplines (Tricco et al., 2018). The PRISMA-ScR methodology and checklists were used in the elaboration of the manuscript. The scoping review proposal will be included in the OSF database (https://osf.io/), and registration information will be presented in the final manuscript. The eligibility criteria are: English language, publication between 07th of August 7th 1998 and August 7th 2019 (20 years), studies on epidemiological features of pediatric keratoconus, on pediatric KC`s clinical features, and those reporting/proposing screening programs. The information sources are PubMed-MEDLINE database and Cochrane Database of Systematic Reviews and keyword combinations of these MeSH terms: keratoconus; child; incidence; prevalence; pediatrics; adolescent; epidemiology. The included articles will be those in English language, with available abstracts, published in the last twenty years, the last search was conducted on August 7th, 2019. Authors of the included articles will be contacted if needed to clarify information. Pertinent references of the included articles will also be listed in the final references. Duplicate references will be excluded. One reviewer will decide the inclusion of articles based on the title and abstract initially. References out of the scope of the review will be excluded. Two other reviewers will analyze the resulting lists and may propose alterations. In case of divergence, a consensus will be reached to decide inclusion. The included articles will be reviewed in full text and their results charted by one author in Excel 2019, in order to summarize research methodologies, describe the included demographic characteristics. The resulting chart will be reviewed by the other two authors. The proposed data chart will be tested by the team on ten articles before its ample use. The studies will be critically analyzed according to the proposed methodology, corresponding results and risk of bias. A flowchart of the processing of the search results included studies, excluded studies, and reasoning will be provided, following PRISMA-ScR recommendations. Synthesis of the information will be done using the charted data using Excel 2019 software and narrative description, resulting in tables and charts to be presented in the manuscript. References: 1. Godefrooij DA, Soeters N, Imhof SM, Wisse RPL. Corneal Cross-Linking for Pediatric Keratoconus: Long-Term Results. Cornea [Internet]. 2016 [cited 2019 Jul 8];35(7):954–8. Available from: http://www.ncbi.nlm.nih.gov/pubmed/27027921 2. McAnena L, Doyle F, O’Keefe M. Cross-linking in children with keratoconus: a systematic review and meta-analysis. Acta Ophthalmol [Internet]. 2017;95(3):229–39. Available from: http://files/5281/McAnena et al. - 2017 - Cross-linking in children with keratoconus a syst.pdf 3. Tricco AC, Lillie E, Zarin W, O’Brien KK, Colquhoun H, Levac D, et al. PRISMA Extension for Scoping Reviews (PRISMA-ScR): Checklist and ExplanationThe PRISMA-ScR Statement. Ann Intern Med [Internet]. 2018 Oct 2;169(7):467–73. Available from: https://doi.org/10.7326/M18-0850 4. Buzzonetti L, Ardia R, Petroni S, Petrocelli G, Valente P, Parrilla R, et al. Four years of corneal keratoplasty in Italian paediatric patients: indications and clinical outcomes. Graefes Arch Clin Exp Ophthalmol. 2016;254(11):2239–45. 5. Naderan M, Jahanrad A, Farjadnia M. Prevalence of Eyelid Laxity and its Association with Ophthalmic Findings and Disease Severity in Patients with Keratoconus. Eur J Ophthalmol. 2017;27(6):670–4. 6. Wallace DK, Chandler DL, Beck RW, Arnold RW, Bacal DA, Birch EE, et al. Treatment of Bilateral Refractive Amblyopia in Children Three to Less Than 10 Years of Age. Am J Ophthalmol [Internet]. 2007;144(4):487–96. Available from: http://dx.doi.org/10.1016/j.ajo.2007.05.040 7. Gabrić N, Dekaris I, Vojniković B, Karaman Z, Mravicić I, Katusić J. Corneal transplantation in children. Coll Antropol [Internet]. 2001 [cited 2019 Jul 8];25 Suppl:17–22. Available from: http://www.ncbi.nlm.nih.gov/pubmed/11817008 8. Gulias-Cañizo R, Gonzalez-Salinas R, Hernandez-Zimbron LF, Hernandez-Quintela E, Sanchez-Huerta V. Indications and outcomes of pediatric keratoplasty in a tertiary eye care center: A retrospective review. Medicine (Baltimore) [Internet]. 2017 Nov [cited 2019 Jul 8];96(45):e8587. Available from: http://www.ncbi.nlm.nih.gov/pubmed/29137083 9. Buzzonetti L, Petrocelli G, Laborante A. Anterior Lamellar Keratoplasty Assisted by IntralaseTM Femtosecond Laser in a Pediatric Patient. J Pediatr Ophthalmol Strabismus [Internet]. 2010;47 Online:e1-4. Available from: http://www.ncbi.nlm.nih.gov/pubmed/21214143 10. Mukhtar S, Ambati BK. Pediatric keratoconus: a review of the literature. Int Ophthalmol [Internet]. 2018 Oct [cited 2019 Jul 8];38(5):2257–66. Available from: http://www.ncbi.nlm.nih.gov/pubmed/28852910 11. El-Khoury S, Abdelmassih Y, Hamade A, Slim E, Cherfan CG, Chelala E, et al. Pediatric Keratoconus in a Tertiary Referral Center: Incidence, Presentation, Risk Factors, and Treatment. J Refract Surg (Thorofare, NJ 1995) [Internet]. 2016 Aug 1 [cited 2019 Jul 8];32(8):534–41. Available from: http://www.ncbi.nlm.nih.gov/pubmed/27505314 12. Shi W, Jin H, Li S, Liu M, Xie L. Indications of paediatric keratoplasty in north China. Clin Exp Ophthalmol. 2007;35(8):724–7. 13. Bajracharya L, Gurung R, DeMarchis E, Oliva M, Ruit S, Tabin G. Indications for keratoplasty in Nepal: 2005 - 2010. Nepal J Ophthalmol [Internet]. 2013 [cited 2019 Jul 8];5(2):207–14. Available from: http://files/5093/Bajracharya et al. - 2013 - Indications for keratoplasty in Nepal 2005 - 2010.pdf 14. Zaidman GW. The pediatric corneal infiltrate. Curr Opin Ophthalmol [Internet]. 2011 [cited 2019 Jul 8];22(4):261–6. Available from: http://www.ncbi.nlm.nih.gov/pubmed/21597372 15. Léoni-Mesplié S, Mortemousque B, Touboul D, Malet F, Praud D, Mesplié N, et al. Scalability and severity of keratoconus in children. Am J Ophthalmol. 2012; 16. Rebenitsch RL, Kymes SM, Walline JJ, Gordon MO. The lifetime economic burden of keratoconus: A decision analysis using a markov model. Am J Ophthalmol [Internet]. 2011;151(5):768-773.e2. Available from: http://files/4617/Rebenitsch et al. - 2011 - The lifetime economic burden of keratoconus a dec.pdf 17. Ganekal S, Gangangouda C, Dorairaj S, Jhanji V. Early outcomes of primary pediatric keratoplasty in patients with acquired, atraumatic corneal pathology. J AAPOS [Internet]. 2011 [cited 2019 Jul 8];15(4):353–5. Available from: http://www.ncbi.nlm.nih.gov/pubmed/21907118 18. Lowe MT, Keane MC, Coster DJ, Williams KA. The outcome of corneal transplantation in infants, children, and adolescents. Ophthalmology [Internet]. 2011 [cited 2019 Jul 8];118(3):492–7. Available from: http://files/5296/Lowe et al. - 2011 - The outcome of corneal transplantation in infants,.pdf 19. Harding SA, Nischal KK, Upponi-Patil A, Fowler DJ. Indications and outcomes of deep anterior lamellar keratoplasty in children. Ophthalmology [Internet]. 2010 [cited 2019 Jul 8];117(11):2191–5. Available from: http://www.ncbi.nlm.nih.gov/pubmed/20663562 20. Limaiem R, Chebil A, Baba A, Ben Youssef N, Mghaieth F, El Matri L. Pediatric penetrating keratoplasty: Indications and outcomes. Transplant Proc [Internet]. 2011 [cited 2019 Jul 8];43(2):649–51. Available from: http://www.ncbi.nlm.nih.gov/pubmed/21440785 21. Buzzonetti L, Petrocelli G, Valente P. Amniotic membrane transplantation in corneal melting after anterior lamellar keratoplasty assisted by femtosecond laser in children. Eur J Ophthalmol [Internet]. 2012 [cited 2019 Jul 8];22(3):477–80. Available from: http://www.ncbi.nlm.nih.gov/pubmed/21971732 22. Majander A, Kivelä TT, Krootila K. Indications and outcomes of keratoplasties in children during a 40-year period. Acta Ophthalmol. 2016;94(6):618–24. 23. Zotta PG, Moschou KA, Diakonis VF, Kymionis GD, Almaliotis DD, Karamitsos AP, et al. Corneal Collagen Cross-linking for Progressive Keratoconus in Pediatric Patients: A Feasibility Study. J Refract Surg [Internet]. 2012 [cited 2019 Jul 8];28(11):793–9. Available from: http://www.ncbi.nlm.nih.gov/pubmed/23347374 24. Kymionis G, Yoo S, Diakonis V, Kankariya V. Management of pediatric keratoconus - Evolving role of corneal collagen cross-linking: An update. Indian J Ophthalmol [Internet]. 2013 [cited 2019 Jul 8];61(8):435. Available from: http://www.ncbi.nlm.nih.gov/pubmed/23925333 25. Ulusoy DM, Göktaş E, Duru N, Özköse A, Ataş M, Yuvacı İ, et al. Accelerated corneal crosslinking for treatment of progressive keratoconus in pediatric patients. Eur J Ophthalmol [Internet]. 2017 [cited 2019 Jul 8];27(3):319–25. Available from: http://www.ncbi.nlm.nih.gov/pubmed/27445064 26. Blackburn BJ, Gu S, Ford MR, de Stefano V, Jenkins MW, Dupps WJ, et al. Noninvasive assessment of corneal crosslinking with phase-decorrelation optical coherence tomography. Investig Ophthalmol Vis Sci [Internet]. 2019;60(1):41–51. Available from: http://files/5293/Blackburn et al. - 2019 - Noninvasive Assessment of Corneal Crosslinking Wit.pdf 27. Soeters N, Van der Lelij A, van der Valk R, Tahzib NG. Corneal Crosslinking for Progressive Keratoconus in Four Children. J Pediatr Ophthalmol Strabismus. 2011; 28. Magli A, Chiariello Vecchio E, Carelli R, Piozzi E, Di Landro F, Troisi S. Pediatric keratoconus and iontophoretic corneal crosslinking: refractive and topographic evidence in patients underwent general and topical anesthesia, 18 months of follow-up. Int Ophthalmol [Internet]. 2016 [cited 2019 Jul 8];36(4):585–90. Available from: http://www.ncbi.nlm.nih.gov/pubmed/26704375 29. Kalkan Akcay E, Uysal BS, Sarac O, Ugurlu N, Yulek F, Cagil N, et al. The Effect of Corneal Epithelium on Corneal Curvature in Patients with Keratoconus. Semin Ophthalmol. 2015; 30. Viswanathan D, Kumar NL, Males JJ. Outcome of Corneal Collagen Crosslinking for Progressive Keratoconus in Paediatric Patients. Biomed Res Int [Internet]. 2014 [cited 2019 Jul 8];2014:1–5. Available from: http://www.ncbi.nlm.nih.gov/pubmed/25013757 31. Godefrooij DA, Gans R, Imhof SM, Wisse RPLL. Nationwide reduction in the number of corneal transplantations for keratoconus following the implementation of cross-linking. Acta Ophthalmol. 2016;94(7):675–8. 32. Godefrooij DA, de Wit GA, Uiterwaal CS, Imhof SM, Wisse RPLL. Age-specific Incidence and Prevalence of Keratoconus: A Nationwide Registration Study. Am J Ophthalmol. 2017;175:169–72. 33. Kanavi MR, Javadi MA, Sanagoo M. Indications for Penetrating Keratoplasty in Iran. Cornea [Internet]. 2007 [cited 2019 Jul 8];26(5):561–3. Available from: http://content.wkhealth.com/linkback/openurl?sid=WKPTLP:landingpage&an=00003226-200706000-00011 34. Downie LE. The Necessity for Ocular Assessment in Atopic Children: Bilateral Corneal Hydrops in an 8 Year Old. Pediatrics [Internet]. 2014 [cited 2019 Jul 8];134(2):e596–601. Available from: http://files/5295/Downie - 2014 - The necessity for ocular assessment in atopic chil.pdf 35. Kaimbo WK. Corneal hydrops associated with vernal conjunctivitis as a presenting sign of keratoconus in a Congolese child. Bull Soc Belge Ophtalmol. 2002; 36. Barsam A, Brennan N, Petrushkin H, Xing W, Quartilho A, Bunce C, et al. Case-control study of risk factors for acute corneal hydrops in keratoconus. Br J Ophthalmol. 2017;101(4):499–502. 37. Sykakis E, Karim R, Evans JR, Bunce C, Amissah-Arthur KN, Patwary S, et al. Corneal collagen cross-linking for treating keratoconus. Cochrane Database Syst Rev [Internet]. 2015 Mar 24 [cited 2019 Sep 13];(3). Available from: http://doi.wiley.com/10.1002/14651858.CD010621.pub2 38. Adachi W, Mitsuishi Y, Terai K, Nakayama C, Hyakutake Y, Yokoyama J, et al. The association of HLA with young-onset keratoconus in Japan. Am J Ophthalmol [Internet]. 2002 Apr [cited 2019 Jul 8];133(4):557–9. Available from: http://www.ncbi.nlm.nih.gov/pubmed/11931792 39. Reeves SW, Ellwein LB, Kim T, Constantine R, Lee PP. Keratoconus in the Medicare population. Cornea. 2009;28(1):40–2. 40. Gokhale N. Epidemiology of keratoconus. Indian J Ophthalmol. 2013;61(8):382. 41. Torres Netto EA, Al-Otaibi WM, Hafezi NL, Kling S, Al-Farhan HM, Randleman JB, et al. Prevalence of keratoconus in paediatric patients in Riyadh, Saudi Arabia. Br J Ophthalmol. 2018;102(10):1436–41. 42. Fonn D. Concerned Parents and Patients. Eye Contact Lens Sci Clin Pract [Internet]. 2010;36(2):67. Available from: http://www.ncbi.nlm.nih.gov/pubmed/20216267 43. Xie L, Qi F, Gao H, Wang T, Shi W, Zhao J. Major shifts in corneal transplantation procedures in north China: 5316 Eyes over 12 years. Br J Ophthalmol. 2009;93(10):1291–5. 44. Leung VC, Pechlivanoglou P, Chew HF, Hatch W. Corneal Collagen Cross-Linking in the Management of Keratoconus in Canada: A Cost-Effectiveness Analysis. In: Ophthalmology. 2017.