title: Normal heterophoric changes: 20 years' follow-up.
abstract: BACKGROUND
  Evaluation of changes in the heterophoric condition of 100 normal individuals over a 20-year period.
  
  
  METHODS
  A retrospective study was undertaken. Charts of 100 normal men were reviewed. Individual changes in the heterophoric status were recorded over a 20-year period. The average value of the phoria at age 18-22 years was compared with the average value at age 34-38 years. Measurements were taken for near and distance fixation. No one was heterotropic. Changes in convergence and accommodation were also calculated.
  
  
  RESULTS
  A 0.9 +/- 1.7 prism diopter increase in esophoria for distance fixation and a 0.6 +/- 2.5 prism diopter increase in exophoria for near fixation were found. These changes were statistically significant (P < 0.001 and P < 0.02 respectively). The near point of convergence receded by 0.5 +/- 1.1 cm (P < 0.001), and a decrease in accommodation over time of 2.8 +/- 1.4 diopters was found (P < 0.001).
  
  
  CONCLUSIONS
  An increase in esophoria for distance fixation and a exophoria for near fixation was found in a 20-year follow-up of 100 normal subjects.
authors.affiliation: Goldschleger Eye Institute Sheba Medical Center, Tel-Hashomer, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Spierer
authors.forename: L
authors.initials: L
authors.lastname: Hefetz
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology; D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology*; D003290:Convergence, Ocular / Q000502:physiology; D005403:Fixation, Ocular; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D012016:Reference Values; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D013285:Strabismus / Q000503:physiopathology*