title: Retinal nerve fibre layer thickness measurements in patients using chloroquine.
abstract: OBJECTIVE
  Previous investigations have suggested that initial retinal damage from chloroquine toxicity occurs in ganglion cells, and other ocular tissues are affected only later on. The aim of this study was to evaluate retinal nerve fibre layer (RNFL) thickness measurements, as assessed by scanning laser polarimetry, in a group of patients under long-term treatment with chloroquine.
  
  
  METHODS
  This case-control study included 34 patients using chloroquine diphosphate and 34 age-matched healthy subjects with no previous history of chloroquine intake. All subjects underwent RNFL assessment using the GDx -- Nerve Fibre Analyser (software v.2.0.01). One eye of each patient was randomly selected for statistical analysis. Peripapillary RNFL measurements were compared between the two groups. For patients using chloroquine, the correlation between RNFL measurements and chloroquine dosage was assessed.
  
  
  RESULTS
  Mean +/- SD RNFL thickness for patients using chloroquine was 60.6 +/- 11.2 microm, 65.6 +/- 13.2 microm, 74.8 +/- 14.8 microm, 36.2 +/- 9.6 microm and 43.8 +/- 7.9 microm for global, superior, inferior, temporal and nasal regions, respectively. In the control group, the corresponding values were 72.1 +/- 12.7 microm, 79.9 +/- 14.8 microm, 88.3 +/- 14.0 microm, 44.2 +/- 12.8 microm and 49.7 +/- 11.9 microm. Mean RNFL thickness measurements from patients using chloroquine were significantly different from those in the control group in all regions (P < 0.05). Thinner RNFL thickness measurements were associated with higher daily dosages of chloroquine.
  
  
  CONCLUSIONS
  Patients under long-term chloroquine treatment had significantly lower RNFL thickness measurements than healthy subjects, and the RNFL loss was correlated to chloroquine daily dosage.
authors.affiliation: Department of Ophthalmology, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Maria Tbc
authors.initials: MT
authors.lastname: Bonanomi
authors.forename: Neuman C
authors.initials: NC
authors.lastname: Dantas
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Medeiros
mesh_terms: D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy; D001837:Body Weights and Measures; D016022:Case-Control Studies; D002738:Chloroquine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000188:drug therapy; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects / Q000473:pathology*; D009900:Optic Nerve / Q000187:drug effects / Q000473:pathology*; D012164:Retinal Diseases / Q000139:chemically induced / Q000175:diagnosis*; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000473:pathology*; D058609:Visual Field Tests; D014794:Visual Fields
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; C023676:chloroquine diphosphate; D002738:Chloroquine