Retinal nerve fibre layer thickness values and their associations with ocular and systemic parameters in Black South Africans

Abstract

Purpose: To measure the retinal nerve fibre layer (RNFL) thickness values and investigate their associations with other parameters in healthy eyes of Black South Africans. Methods: 600 participants with healthy eyes, of whom 305 (50.83%) were males and 295 (49.17%) were females, with a mean age of 28.15 ± 13.09 years, underwent a detailed ophthalmic examination. RNFL thickness was measured by iVue SD-OCT. Results: The mean global RNFL thickness was 110.01 ± 7.39 μm. The RNFL was thickest inferiorly (135.06 ± 9.66 µm) and superiorly (131.72 ± 10.46 µm), thinner nasally (87.24 ± 13.22 µm), and thinnest temporally (73.63 ± 15.66 µm). Multivariate analysis showed that thicker mean global RNFL thickness was significantly associated with younger age, shorter axial length (AL) and hyperopia (p < 0.001). Mean RNFL thickness decreased by approximately 0.11 µm per year of aging life, and by 1.02 µm for each 1-mm of axial elongation. There was a 0.62 µm RNFL thickness increase for every dioptre change in spherical power towards more hyperopia. Conclusion: Mean RNFL thickness values and their associations established in this population may be of clinical value when assessing factors that influence this parameter and diagnosing diseases affecting it.

Normative Values of Retinal Nerve Fibre Layer Thickness and Optic Nerve Head Parameters and Their Association with Visual Function in an African Population

“…Consistent with published data (Table 6), RNFL was thickest in the inferior quadrant, followed by the superior quadrant, nasal quadrant, and temporal quadrant [20,22,24] and followed the ISNT rule. Age was observed to have a negative correlation with all RNFL parameters (Figure 1).…”

“…RNFL was observed to decline gradually as age increases with a 0.25 μm reduction in mean RNFL thickness per year of aging. Similar published finding of 0.38 μm per year has been reported using scanning laser polarimetry [29] and OCTs by Knight and colleagues [20], 0.19 μm/y, and Mashige and Oduntan [24] at a rate of decline of 0.11 μm/y [24]. Sex was found to affect all retinal nerve layers with females, 104.84 ± 6.90, having higher RNFL thickness compared with males, 99.80 ± 7.18.…”

“…e present study calculated similar values to those in studies conducted on black Africans. Similar studies carried out on African populations in Nigeria and South Africa reported averages of RNFL 104.2 ± 10.7 μm and 110 ± 7.4 μm, respectively [24,25] (Table 6).…”

“…e SD-OCTcollects data 100 times faster than conventional time-domain (TD) OCT [11,23]. To the best of our knowledge, only two studies by Mashige and Oduntan [24] in black South Africans which used iVue-100 SD-OCT and Sani et al [25] in Nigeria which used Stratus TD-OCT can be cited. ough Ghana is known to have the highest prevalence of glaucoma cases in West Africa, no normative data for the Ghanaian population have been determined, and therefore judgment on the integrity of RNFL and OHN parameters is made with reference to other races.…”

Retinal nerve fibre layer and ganglion cell complex thickness in patients with keratoconus

“…Nevertheless, such comparisons across studies should be interpreted with caution as RNFL thickness varies with several ocular and demographic factors. 51,55 Few studies have measured RNFL thickness in individuals with keratoconus and these studies have reported conflicting results. The mean global RNFL thickness in the keratoconus group (~ 99 µm) in the present study is comparable to the mean value (97 µm) reported by Cankaya et al 3 in individuals with keratoconus.…”