To the Editor:

We present normative optical coherence tomography (OCT) peripapillary data for healthy adults of African descent (AD) and wish to emphasise the lack of normative control data from all regions of sub-saharan Africa.

We read with interest the recent article by Yashadhana et al. calling for improved diversity in global eye health leadership [1]. Leadership is not the only area of eye health where diversity could be improved. We are currently investigating TEON: a bilateral subacute optic neuropathy of unknown aetiology affecting young people in Tanzania [2]. The condition demonstrates similar clinical and temporal characteristics to Leber’s Hereditary Optic Neuropathy (LHON). As part of the TEON Study—a collaborative research project that aims to identify the causes of TEON—we sought to compare the OCT findings of TEON and LHON, utilizing a new OCT scanner (Topcon 3D OCT-1 Maestro, Topcon Medical Systems, Oakland, NJ, USA) at Muhimbili National Hospital.

To allow thorough comparison of OCT data, we need a representative normative dataset. Only 20% of the normative dataset of our OCT analysis software contains data from people of AD and only 45% were under the age of 40 [3]. The AD and Glaucoma Evaluation Study, a study that investigated glaucoma in American AD patients, showed significant baseline differences in optic nerve parameters between healthy participants of African and European descent [4].

We therefore conducted a literature search for normative data for OCT peripapillary retinal nerve fibre layer (pRNFL) thickness measurements in healthy adult AD participants, the results of which can be seen in Table 1.

Table 1 Studies reporting normative pRNFL OCT data for adult participants of African descent.
Full size table

The difference between the averages is in agreement with studies that have previously examined ethnic differences in pRNFL OCT thicknesses—namely that AD patients have thinner temporal peripapillary RNFL thicknesses and thicker RNFL in the other quadrants [5].

It should be noted that many of these RNFL studies concern glaucoma, primarily a disease of the elderly, hence normative data may be skewed by age, as well as differences in scan equipment, scan technique, and optic disc morphology.

The variation in RNFL thicknesses seen in Table 1 shows the difficulties in comparing OCT scan data and emphasises the need for more extensive normative control data from all regions of sub-saharan Africa. This article hopefully highlights the heterogenous nature of the term ‘AD’ and that there are no published normative datasets for East African patients.