Sir,

We thank Drs A Dhital and M Mohamed1 for their interest in our report2 and for their stimulating comments.

The distribution of the crystals in our case exactly matches that described by Sarraf et al3 in their original series first describing West African crystalline maculopathy (WACM) in 2003. They describe the crystals as superficial, refractile, yellow or green in appearance, bilateral and asymmetric in distribution, and focally deposited within the fovea.

Two published reports to date have documented the location of the crystals using optical coherence tomography (OCT). The first revealed multiple discrete hyperreflective lesions in the innermost retinal layers in the region of the fovea (Figure 1).4 The second report visualized the crystals in the layer of Henle, the foveal portion of the outer plexiform layer of the retina (Figure 2).5 Similarly, our report localized the crystals to Henle's layer in the fovea (Figure 3).2 Given that the fovea lacks the inner retinal layers, the layer of Henle represents the innermost layer in the fovea, which explains the superficial location of the crystals.6 In the authors’ letter, the crystals appear to be located, at least in part, in Henle's layer. However, their scan appears to be through a perifoveal location where the inner retinal layers are still present, which explains the deeper location of the crystals.

Figure 1
figure 1

Optical coherence tomography of fovea of patient with WACM showing refractile crystals (arrows) in inner foveal layers, reproduced from Baker et al.4 Copyright 2009 Wolters Kluwer Health. All rights reserved.

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Figure 2
figure 2

Optical coherence tomography of fovea of patient with WACM showing refractile crystals in inner foveal layers, reproduced from Rajak et al.5 Copyright 2009 American Medical Association. All rights reserved.

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Figure 3
figure 3

(a and b) Optical coherence tomography of fovea of patient with WACM showing refractile deposits in inner foveal layers, reproduced from our original article.2

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Concurrent pathology affecting the blood–retinal barrier is not a consistent feature in the cases of WACM reported to date. In Sarraf et al's3 original series first describing the disease, only 50% (three of the six) patients had diabetes.

Our report describes a similar phenotype in a North African patient from Egypt. In our opinion, this is a typical case of WACM, if not for the patient's distinct ethnic background. If confirmed in future studies, this report may help expand on the geographic origins of the disease and elucidate aetiological factors.