title: The relationship of central foveal thickness to urinary iodine concentration in retinitis pigmentosa with or without cystoid macular edema.
abstract: OBJECTIVE
  Current treatments for cystoid macular edema (CME) in retinitis pigmentosa (RP) are not always effective, may lead to adverse effects, and may not restore visual acuity. The present research lays the rationale for evaluating whether an iodine supplement could reduce CME in RP.
  
  
  OBJECTIVE
  To determine whether central foveal thickness (CFT) in the presence of CME is related to dietary iodine intake inferred from urinary iodine concentration (UIC) in nonsmoking adults with RP.
  
  
  METHODS
  We performed a cross-sectional observational study of 212 nonsmoking patients aged 18 to 69 years referred to our institution for RP with visual acuity of no worse than 20/200 in at least 1 eye.
  
  
  METHODS
  Retinitis pigmentosa with or without CME.
  
  
  METHODS
  With the eye as the unit of analysis, the relationship of log CFT measured by optical coherence tomography to UIC measured from multiple spot samples and represented as a 3-level classification variable (<100, 100-199, and ≥200 µg/L), assigning greater weight to patients with more reliable UIC estimates.
  
  
  RESULTS
  Analyses were limited to 199 patients after excluding 11 who failed to return urine samples for measuring UIC and 2 outliers for UIC. Of the 199 patients, 36.2% had CME in 1 or both eyes. Although log CFT was inversely related to UIC based on findings from all eyes (P = .02), regression of log CFT on UIC separately for eyes with and without CME showed a strong inverse significant relationship for the former group (P < .001) and no significant relationship for the latter group (P = .66) as tested. For the eyes with CME, CFT ranged from a geometric mean of 267 µm for a median UIC of less than 100 µg/L to a geometric mean of 172 µm for a median UIC of 200 µg/L or greater. In contrast, we found no significant association between CME prevalence and UIC based on the entire sample as tested (odds ratio, 1.01 [95% CI, 0.38-2.67]; P = .99).
  
  
  CONCLUSIONS
  A higher UIC in nonsmoking adults with RP was significantly associated with less central foveal swelling in eyes with CME. Additional study is required to determine whether an iodine supplement can limit or reduce the extent of CME in patients with RP.
authors.affiliation: Berman-Gund Laboratory for the Study of Retinal Degenerations, Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Sandberg
authors.affiliation: Section of Endocrinology, Diabetes and Nutrition, Boston University School of Medicine, Boston, Massachusetts.
authors.forename: Elizabeth N
authors.initials: EN
authors.lastname: Pearce
authors.affiliation: Berman-Gund Laboratory for the Study of Retinal Degenerations, Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston.
authors.forename: Shyana
authors.initials: S
authors.lastname: Harper
authors.affiliation: Berman-Gund Laboratory for the Study of Retinal Degenerations, Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston.
authors.forename: Carol
authors.initials: C
authors.lastname: Weigel-DiFranco
authors.affiliation: Retina Service, Massachusetts Eye and Ear Infirmary, Boston.
authors.forename: Lois
authors.initials: L
authors.lastname: Hart
authors.affiliation: Berman-Gund Laboratory for the Study of Retinal Degenerations, Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston.
authors.forename: Bernard
authors.initials: B
authors.lastname: Rosner
authors.affiliation: Berman-Gund Laboratory for the Study of Retinal Degenerations, Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston.
authors.forename: Eliot L
authors.initials: EL
authors.lastname: Berson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D004032:Diet; D005260:Female; D005584:Fovea Centralis / Q000473:pathology*; D006801:Humans; D007455:Iodine / Q000652:urine*; D008269:Macular Edema / Q000175:diagnosis / Q000652:urine*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D012174:Retinitis Pigmentosa / Q000175:diagnosis / Q000652:urine*; D041623:Tomography, Optical Coherence; D014792:Visual Acuity; D055815:Young Adult
chemical_list: D007455:Iodine