title: Bilateral Symmetry of Visual Function Loss in Cone-Rod Dystrophies.
abstract: To investigate bilateral symmetry of visual impairment in cone-rod dystrophy (CRD) patients and understand the feasibility of clinical trial designs treating one eye and using the untreated eye as an internal control.
  
  
  
  This was a retrospective study of visual function loss measures in 436 CRD patients followed at the Ophthalmology Department of the Catholic University in Rome. Clinical measures considered were best-corrected visual acuity, focal macular cone electroretinogram (fERG), and Ganzfeld cone-mediated and rod-mediated electroretinograms. Interocular agreement in each of these clinical indexes was assessed by t- and Wilcoxon tests for paired samples, structural (Deming) regression analysis, and intraclass correlation. Baseline and follow-up measures were analyzed. A separate analysis was performed on the subset of 61 CRD patients carrying likely disease-causing mutations in the ABCA4 gene.
  
  
  
  Statistical tests show a very high degree of bilateral symmetry in the extent and progression of visual impairment in the fellow eyes of CRD patients.
  
  
  
  These data contribute to a better understanding of CRDs and support the feasibility of clinical trial designs involving unilateral eye treatment with the use of fellow eye as internal control.
authors.affiliation: Istituto di Neuroscienze Consiglio Nazionale delle Ricerche (CNR) Pisa, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Galli-Resta
authors.affiliation: Institute of Ophthalmology, Policlinico Gemelli, Catholic University, Rome, Italy.
authors.forename: Benedetto
authors.initials: B
authors.lastname: Falsini
authors.affiliation: Istituto di Fisiologia Clinica CNR, Pisa, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Rossi
authors.affiliation: Institute of Ophthalmology, Policlinico Gemelli, Catholic University, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Piccardi
authors.affiliation: Bietti Foundation, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Ziccardi
authors.affiliation: Tecnologie e Salute, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Antonello
authors.initials: A
authors.lastname: Fadda
authors.affiliation: Institute of Ophthalmology, Policlinico Gemelli, Catholic University, Rome, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Minnella
authors.affiliation: Institute of Ophthalmology, Policlinico Gemelli, Catholic University, Rome, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Marangoni
authors.affiliation: Institute of Ophthalmology, Policlinico Gemelli, Catholic University, Rome, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Placidi
authors.affiliation: Institute of Ophthalmology, Policlinico Gemelli, Catholic University, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Campagna
authors.affiliation: Institute of Ophthalmology, Policlinico Gemelli, Catholic University, Rome, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Abed
authors.affiliation: MAGI Laboratory for Medical Genetics, Rovereto, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Bertelli
authors.affiliation: MAGI Laboratory for Medical Genetics, Rovereto, Italy.
authors.forename: Monia
authors.initials: M
authors.lastname: Zuntini
authors.affiliation: Istituto di Informatica e Telematica CNR, Pisa, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Resta
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001766:Blindness / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D002986:Clinical Trials as Topic; D000071700:Cone-Rod Dystrophies / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D018450:Disease Progression; D004596:Electroretinography; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D015588:Observer Variation; D012189:Retrospective Studies; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: C056475:ABCA4 protein, human; D018528:ATP-Binding Cassette Transporters