Comparison of retinal nerve fiber layer (RNFL) thickness and perimetry findings in glaucomatous patients

Aim: to determine the value of RNFL thickness at which visual field defect becomes detectable. Methods: Our study included 29 normal subject and 36 glaucomatous patient (one eye per person) .Every person was examined by OCTOPUS perimetry with glaucoma 30-2 program, and peripapillary RNFL thickness was measured by HIEDELBERGSPECTRALIS SD_OCT. Results: comparison of results showed higher sensitivity of OCT compared to Perimetry. Mean RNFL thickness at which visual field defect showed was 87 microns. Superior RNFL thickness value which correlated with inferior visual field defect was 101 microns, whereas inferior RNFL thickness value which correlated with superior visual field defect was 75 microns .and the difference in RNFL thickness between normal and glaucomatous visual field was significant (p<0.001). Conclusion: in open-angle glaucoma , it needs significant thinning in RNFL before visual field defects becomes detectable.

Macular Thickness Measurements in Diabetic Patients Using the Optical Coherence Tomography (OCT)

The OCT is a recent diagnostic tool for non-invasive tissue examination, which has been used in clinical practice since 1995. The OCT is similar to the ultrasonic tomography in that it relies on optical waves rather than ultrasound ones. The ability to obtain highcontrast images of the retina in a non-invasive manner has made this examination very important in retinal diseases associated with macula.. Therefore, our objective is to study the statistical values of the measurements of the macular thickness using Optical Coherence Tomography (OCT) and the relationship of each value to age, sex, medication ,duration of diabetes ,and the visual acuity in diabetic eyes. Therefore, the accurate measurement of the macular thickness is important to follow up disease progression, evaluate treatment and accurately diagnose lesions of visual acuity. The thickness of the macula in the left and right eye was thicker in males than in females. We find out that the visual ability declines with age. For both left and right eyes, the thickness of the macula increases with age and the content of the macula correlates with its thickness and the period of the disease. There are no statistically significant differences of the thicknesses with different treatment types (insulin or pills),so we notice a correlation between the visual acuity and the thickness of the macula in both eyes ,so that the higher the thickness of the macula in diabetic patients ,the lower the visual acuity . In the study of the different parts of the macula, the internal part is thicker than the external part and the nasal part is thicker than the different parts of the macula, and the nasointernal part is the thickest.