الفهرس 
General Features of Optic NerveOnly 14 pages are availabe for public view
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Abstract
Glaucoma is a progressive degenerative neuropathy. It is one of the main causes of irreversible legal blindness worldwide and more specifically the second cause of loss of vision in patients over 40 years of age in the developed countries, with an important impact on quality of life. In the first stages, glaucoma-induced structural alterations (apoptosis of ganglion cells, nerve fiber loss, and optic disc alteration) are asymptomatic and cannot be diagnosed clinically until functional changes are detected such as early scotomas in the visual field. It is demonstrated that 40%–50% of axonal loss may occur before any change in visual function is detected with perimetry.
This study was done to evaluate the relationship between the retinal nerve fiber layer thickness measurements; using optical coherence tomography, and the corresponding retinal sensitivity changes; using visual field perimetry, in cases of ocular hypertension and early glaucoma.
This study was done on 60 eyes. group I contained 30 eyes with ocular hypertension and group II contained 30 eyes with early diagnosed primary open angle glaucoma.
The results of the study showed prevalence of ocular hypertension and early POAG in males and age above 40s, higher IOP measurements and further progressive changes in optic nerve head (C/D ratio) in POAG group, no difference in corneal thickness of both groups, a significant difference in all visual field indices showing more visual field damage in POAG eyes and a significant difference in inferior and temporal thickness of RNFL being thinner in POAG eyes whilst there was no difference in other areas of RNFL.
A significant correlation between the temporal thickness of RNFL and indices of VF was observed for patients with ocular hypertension. Also, a significant correlation between the temporal thickness of RNFL and mean sensitivity index of VF was observed for patients with early POAG. Otherwise, there was no significant correlation between visual field indices and other areas of RNFL thickness in both groups.
In conclusion, average RNFL thickness is not a highly reliable index for early diagnosis of glaucoma and for the follow-up of patients with ocular hypertension or POAG. Segmental RNFL thickness (especially temporal) seems to be a more reliable index. Deep structural alterations with OCT examination constitute an important indication of early functional changes, even if they are not still detected with perimetry. The MS index of VF seems to be more sensitive for the follow-up of patients with ocular hypertension.