title: Reversible increase of intraocular pressure in subclinical hypothyroid patients.
abstract: OBJECTIVE
  The aim of the study was to analyse the relationship between the ocular parameters, namely intraocular pressure (IOP), and the early forms of subclinical hypothyroidism.
  
  
  METHODS
  Fifty-three subjects (9 male and 44 female) aged from 18 to 45 years (mean 32 +/- 7 years) were selected for this study. Twenty-nine met the criteria of subclinical hypothyroidism and 24 euthyroid subjects, age- and sex-matched, were used as controls.
  
  
  METHODS
  All individuals underwent a complete ocular examination, including visual field examination and serial measurement of IOP by means of a Goldmann tonometer. A tonographic examination was also performed.
  
  
  RESULTS
  The hypothyroid patients showed a substantially higher pressure in both eyes compared with control subjects (right eye = 17.52 +/- 4.74 vs 13.42 +/- 1.95 mmHg, P < 0.0001; left eye = 17.55 +/- 3.99 vs 13.71 +/- 1.55 mmHg, P < 0.0001). Indeed, the tonometric pressure exceeded 18 mmHg in 11 out of the 29 (38%) patients in the right eye and in 8 out of 29 (27%) patients in the left eye. The outflow index was normal in all subjects except in two hypothyroid patients. After two months of L-thyroxine (L-T4) replacement therapy, only one patient continued to show tonometric values above 18 mmHg and the hypothyroid patients showed a significant reduction in mean IOP in both eyes compared with pre-treatment values (right eye = 14.96 +/- 1.32 mmHg, P < 0.0097; left eye = 15.03 +/- 1.38 mmHg, P < 0.0018). Treatment did not lead to any change in the outflow indices; however, the C value (outflow coefficient at the sclerocorneal corner) returned to normal in the two patients with increased pre-treatment tonographic values.
  
  
  CONCLUSIONS
  These findings indicate that the intraocular pressure is increased even in subclinical hypothyroid patients and that, at this early stage, the impairment is fully reversible with L-T4 therapy.
authors.affiliation: Second Chair of Endocrinology, University La Sapienza, Roma, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Centanni
authors.forename: R
authors.initials: R
authors.lastname: Cesareo
authors.forename: O
authors.initials: O
authors.lastname: Verallo
authors.forename: M
authors.initials: M
authors.lastname: Brinelli
authors.forename: G
authors.initials: G
authors.lastname: Canettieri
authors.forename: N
authors.initials: N
authors.lastname: Viceconti
authors.forename: M
authors.initials: M
authors.lastname: Andreoli
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy / Q000503:physiopathology*; D007429:Intraocular Pressure / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013974:Thyroxine / Q000627:therapeutic use; D014065:Tonometry, Ocular
chemical_list: D013974:Thyroxine