ABSTRACT
OBJECTIVE: Evaluation of intraocular pressure (IOP) adjusted for central corneal thickness (CCT) screening for open-angle glaucoma (OAG) in an at-risk population. STUDY DESIGN: Community-based screening clinic. PARTICIPANTS: 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.
Subject(s)
Cornea/anatomy & histology , Glaucoma, Open-Angle/diagnosis , Intraocular Pressure , Optic Nerve Diseases/diagnosis , Tonometry, Ocular/methods , Black People/ethnology , Canada , Cornea/diagnostic imaging , Cross-Sectional Studies , False Positive Reactions , Female , Glaucoma, Open-Angle/ethnology , Humans , Likelihood Functions , Male , Middle Aged , Nomograms , Ocular Hypertension/diagnosis , Ocular Hypertension/ethnology , Optic Nerve Diseases/ethnology , Predictive Value of Tests , ROC Curve , Risk Factors , Sensitivity and Specificity , Ultrasonography , Vision Disorders/diagnosis , Vision Disorders/ethnology , Visual Fields , White People/ethnologyABSTRACT
We have ascertained a large number of individuals and families with exfoliation syndrome in order to clarify the disorder's mode of inheritance. Patients with exfoliation syndrome and their relatives were recruited from the practices of a group of ophthalmologists in Maritime Canada. The degree to which the subjects were affected was graded according to a standardized 1-4-point clinical scheme. Pedigrees were constructed from information supplied by family members and from genealogical sources. A total of 782 patients and relatives participated, of whom 467 were definitely affected. The mean age of affected males and females did not differ significantly, but females appeared to be more severely affected at ascertainment than males. More than half of the affected subjects had definite exfoliation in only one eye. Approximately 30 multiplex families were discovered, including one containing 23 affected members among a total of 137 examined individuals that constitutes the largest exfoliative pedigree thus far described. We observed well-documented paternal transmission of the trait, a finding that has not to our knowledge been previously reported. Clustering of cases in the families provides evidence for the involvement of genetic factors. The possibility of homozygosity is suggested in a few patients by the earlier or more frequent presentation of the disorder in the offspring of two affected parents or consanguineous pairings. Although a multifactorial mode of inheritance cannot be excluded, exfoliation syndrome appears to be inherited as an autosomal dominant trait whose late onset and incomplete penetrance poses a significant but not insuperable obstacle to pedigree construction.
