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Reliability of echographic examination for the study of optic nerve cupping

Confiabilidade do exame ecográfico como método de estudo da escavação do n ervo óptico

SUMMARY

Purpose:

To investigate the reliability and applicability of echography to detect optic nerve cupping smaller than or equal to 0.3 and greater than or equal to 0.9.

Patients and Method:

Fifty-three eyes from 30 patients, with transparent optic media, underwent contact B-scan echography to evaluate optic disc cupping. On biomicroscopy, twenty-six eyes presented small (Group 1) and 27 large (Group II) optic nerve cupping.

Results:

B-scan images of the optic disc were evaluated by two observers and ocular echography was considered reliable with a Kappa index of 0.77 (± 0.14). Sensitivity and specificity were 71.4% (53.4 - 81.1) and 96.2% (78.4 - 99.8), respectively, with a confidence interval of 95 % •The positive and negative predictive values found for the sample were 95.2 % (74.1 - 99.8) and 78.1 % (59.6 - 90.1), respectively.

Conclusion:

Echography is a reliable method to evaluate optic disc cupping when s; 0.3 and > 0.9. However, as a screening method it would be more important in the case of negative results.

Keywords:
Ophthalmic ultrasound; Optic nerve cupping; Glaucoma

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