Are All Retinal Nerve Fiber Layer Defects on Optic Coherence Tomography Glaucomatous?

Abstract

Objectives: In this study, we investigated the patients who were referred to our clinic with a prediagnosis of glaucoma based on retinalnerve fiber layer (RNFL) defects on optic coherence tomography (OCT) but were determined to have nonglaucomatous RNLF defectsupon detailed examination.Materials and Methods: The ophthalmic examination notes, OCT images, Heidelberg retinal tomography (HRT) II and fundusphotographs of 357 patients were retrospectively evaluated. Final diagnoses of these patients were investigated.Results: Of the 357 patients, 216 (60.5%) were diagnosed as open angle glaucoma, 33 (9.2%) as low-tension glaucoma, 39 (10.9%)as pre-perimetric glaucoma. The ophthalmic examinations of 14 patients (3.9%) were normal and there were no RNFL defects in OCTexaminations after dilatation. In 39 patients (10.9%), the ophthalmic and optic disc examinations were completely normal and noetiologic factor explaining RNFL defects was found. Twenty-two eyes of 16 patients (4.5%) were included in this study (the mean agewas 53.8±11.5 years; 9 men and 7 women). After detailed questioning of the medical history and systemic and neurologic examinations,a diagnosis of ischemic optic neuropathy was made in 11 eyes (10 patients) (2.8%), optic neuritis in 3 eyes (2 patients) (0.6%), optic discdrusen in 4 eyes (2 patients) (0.6%), pseudotumor cerebri in 2 eyes (1 patient) (0.3%), and cerebral palsy in 2 eyes (1 patient) (0.3%).Conclusion: Decrease in RNFL thickness on OCT images alone may be misleading in glaucoma examination. In cases where opticdisc cupping is not evident, diagnosis should not be based on OCT RNFL examinations alone, and the patient’s medical history, detailedophthalmic examination, OCT optic disc parameters, HRT, and visual field tests should all be carefully evaluated together.