Evaluation of focal defects of the nerve fiber layer using optical coherence tomography.

OBJECTIVE

To analyze glaucomatous eyes with known focal defects of the nerve fiber layer (NFL), relating optical coherence tomography (OCT) findings to clinical examination, NFL and stereoscopic optic nerve head (ONH) photography, and Humphrey 24-2 visual fields.

DESIGN

Cross-sectional prevalence study.

PARTICIPANTS

The authors followed 19 patients in the study group and 14 patients in the control group.

INTERVENTION

Imaging with OCT was performed circumferentially around the ONH with a circle diameter of 3.4 mm using an internal fixation technique. One hundred OCT scan points taken within 2.5 seconds were analyzed.

MAIN OUTCOME MEASURES

Measurements of NFL thickness using OCT were performed.

RESULTS

In most eyes with focal NFL defects, OCTs showed significant thinning of the NFL in areas closely corresponding to focal defects visible on clinical examination, to red-free photographs, and to defects on the Humphrey visual fields. Optical coherence tomography enabled the detection of focal defects in the NFL with a sensitivity of 65% and a specificity of 81%.

CONCLUSION

Analysis of NFL thickness in eyes with focal defects showed good structural and functional correlation with clinical parameters. Optical coherence tomography contributes to the identification of focal defects in the NFL that occur in early stages of glaucoma.