Intraocular pressure adjusted for central corneal thickness as a screening tool for open-angle glaucoma in an at-risk population.
OBJECTIVE
Evaluation of intraocular pressure (IOP) adjusted for central corneal thickness (CCT) screening for open-angle glaucoma (OAG) in an at-risk population.


METHODS
Community-based screening clinic.


METHODS
Three hundred and forty-nine persons of black race, or >50 years of age, or with a positive family history of glaucoma.


METHODS
Ophthalmological examination including Goldmann applanation tonometry, ultrasonographic corneal pachymetry, and visual field testing. Glaucomatous optic nerve damage with visual field loss was the gold standard. IOP was adjusted for CCT based on 3 nomograms. Results were compared with screening using unadjusted IOP. Outcome measures included sensitivity, specificity, areas under the receiver operating characteristic (ROC) curves, positive and negative predictive values (PPVs and NPVs), as well as positive and negative likelihood ratios.


RESULTS
No significant difference in CCT was found between those with glaucoma (560 [SD 37] microm, n = 31) and those without (557 [SD 35] microm, n = 233). Screening adjusted IOPs for glaucoma with an IOP > 21 mm Hg resulted in PPVs of 23.8% to 25% and NPVs of 89.3% to 89.6%, similar to preadjustment values. Areas under the ROC curves varied from 0.544 to 0.571 post adjustment from the initial value of 0.574.


CONCLUSIONS
IOP adjusted for CCT is unlikely to improve tonometry as a screening tool for OAG in an at-risk population.
Ophthalmology Research Unit, Maisonneuve-Rosemont Hospital, University of Montreal, Montreal, Que.
A
A
de Saint Sardos
A
A
Kamdeu Fansi
M
M
Chagnon
P J
PJ
Harasymowycz
D044383:Black People / Q000208:ethnology; D002170:Canada; D003315:Cornea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D003430:Cross-Sectional Studies; D005189:False Positive Reactions; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000208:ethnology; D006801:Humans; D007429:Intraocular Pressure; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D049451:Nomograms; D009798:Ocular Hypertension / Q000175:diagnosis / Q000208:ethnology; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000208:ethnology; D011237:Predictive Value of Tests; D012372:ROC Curve; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014065:Tonometry, Ocular / Q000379:methods*; D014463:Ultrasonography; D014786:Vision Disorders / Q000175:diagnosis / Q000208:ethnology; D014794:Visual Fields; D044465:White People / Q000208:ethnology