title: Ocular axial length in homocystinuria patients with and without ocular changes: effects of early treatment and biochemical control.
abstract: OBJECTIVE
  To establish whether myopia in homocystinuria could be due to increased ocular axial length.
  
  
  METHODS
  Measurement of ocular axial length by A-scan ultrasound in eyes of homocystinuria patients.
  
  
  RESULTS
  Patients were divided into three groups. Group I, with no ocular pathology (28 eyes), had mean refractive error of -0.25 D (spherical equivalent) and mean axial length of 23.4 mm +/- 0.9 (+/-1 standard deviation) mm. Group II, with phacodonesis or lens subluxation (12 eyes), had mean refractive error of -10.7 D and mean axial length of 23.8 mm +/-1.9 mm. Patients with phacodonesis had simple myopia whereas those with lens subluxation had marked myopic astigmatism. Group III included patients with complete lens dislocation in at least one eye (12 eyes) and were optically aphakic with a mean refractive error of +12.9 D and mean axial length of 24.9 mm +/- 0.9 mm. All Group I patients had good long-term metabolic control while those in Groups II and III did not. Group III eyes had significantly longer mean axial length than Group I (P =.0018) or normal eyes (P =.0163). There was no statistical difference in mean axial length between Group I and normal eyes.
  
  
  CONCLUSIONS
  Ocular axial length is significantly increased in individuals with homocystinuria and lens dislocation. Increased axial length is a complication that has not been previously described in homocystinuria and may be preventable with early treatment and good biochemical control.
authors.affiliation: Department of Paediatric Ophthalmology, Dublin, Ireland.
authors.forename: Alan
authors.initials: A
authors.lastname: Mulvihill
authors.forename: Michael
authors.initials: M
authors.lastname: O'Keeffe
authors.forename: Sufin
authors.initials: S
authors.lastname: Yap
authors.forename: Eileen
authors.initials: E
authors.lastname: Naughten
authors.forename: Pamela
authors.initials: P
authors.lastname: Howard
authors.forename: Bernadette
authors.initials: B
authors.lastname: Lanigan
mesh_terms: D000293:Adolescent; D000328:Adult; D001251:Astigmatism / Q000209:etiology* / Q000503:physiopathology; D001837:Body Weights and Measures; D002648:Child; D003541:Cystathionine beta-Synthase / Q000172:deficiency; D018753:Diet, Protein-Restricted; D005123:Eye / Q000254:growth & development / Q000473:pathology*; D005260:Female; D006711:Homocystine / Q000097:blood; D006712:Homocystinuria / Q000150:complications* / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D007906:Lens Subluxation / Q000209:etiology / Q000628:therapy; D008297:Male; D009216:Myopia / Q000209:etiology* / Q000503:physiopathology; D011736:Pyridoxine / Q000627:therapeutic use*; D014792:Visual Acuity
chemical_list: D006711:Homocystine; D003541:Cystathionine beta-Synthase; D011736:Pyridoxine