Introduction

A cherry red spot (CRS) is an important fundus finding. It includes posterior pole retinal thickening, nontransparency, and color changes.1 In some storage disorders, its related materials can accumulate in the ganglion cell layers causing retinal swelling and loss of retinal transparency. Owing to the absence of ganglion cell layers in the fovea and the transparent appearance of retina, choroidal structures can be seen in the fovea.2 CRS can be seen in central retinal artery (CRA) occlusion. Retinal ischemia can cause pale appearance in perimacular structure, but the fovea keeps its normal appearance.1 Dapson and methanol toxicity can cause CRS as well.3, 4 In addition, co-occurrence of cataract and CRS was reported in some diseases.5 However, isolated CRS or co-occurrence of CRS and cataract without any underlying diseases has not reported before. We report the cases due to the presence of their co-occurrence without any systemic or ocular disease.

Case reports

Case 1

A 16-year-old male presented with poor visual acuity and deviation in his left eye. He had left eye deviation as an infant and he had previous strabismus surgery 10 years ago. On ophthalmological examination, the best-corrected visual acuity (BCVA) was 20/20 on the right eye and 20/400 on the left eye (with snellen chart). Forty-prism diopter of left eye exotropia was detected. Intraocular pressure (IOP) was 10 mm Hg bilaterally. Anterior segment exam showed bilateral punctate multiple lens opacities (PMLOs) (Figure 1a). Bilateral CRS appearance was present on the fundus examination (Figure 1b). All family members were examined due to presence of cross-cousin marriage of the parent. On family examination, his mother and father had normal ophthalmologic examination.

Figure 1
figure 1

A 16-year-old patient presenting multiple lens opacities (a) and CRS appearance (b) in the right eye. Multiple lens opacities (c) and CRS appearance (d) in right eye of 14-year-old patient.

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Case 2

A 14-year-old male sibling was admitted to the control eye examination. On ophthalmological examination, the BCVA was 20/20 bilaterally (with snellen chart) IOP was 12 mm Hg bilaterally. On anterior segment examination, bilateral PMLO were detected (Figure 1c). On fundus examination, bilateral CRS appearance was present (Figure 1d).

Case 3

A 11-year-old male sibling had normal visual acuity and normal IOP. Anterior segment exam demonstrated bilateral PMLO (Figure 2a). Bilateral CRS appearance was present on the fundus examination (Figure 2b).

Figure 2
figure 2

Multiple lens opacities (a) and CRS appearance (b) in right eye of 11-year-old patient. Multiple lens opacities (c) and CRS appearance (d) in right eye of 4-year-old patient.

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Case 4

A 4-year-old female sibling had normal visual acuity and normal IOP. On anterior segment examination, bilateral PMLO were detected (Figure 2c). On fundus examination, bilateral CRS appearance was present (Figure 2d).

All siblings were referred to pediatric endocrinology and metabolic diseases. After their detailed examination, no mental or systemic diseases were detected. A past medical history of the siblings was negative for trauma history, neurological disease, intellectual impairment, drug toxicity, muscle disorders, and cardiovascular diseases. Further laboratory tests for systemic and storage diseases were unremarkable (Table 1). The siblings were diagnosed with isolated CRS and scheduled for periodic follow ups.

Table 1 The disorders that have role in cherry red spot etiopathogenesis and performed tests
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Discussion

CRS at the macula is commonly seen in hereditary storage diseases, CRA occlusion due to several causes, and several drug toxicities.2, 6 Hereditary metabolic storage disorders presenting with CRS include Tay–Sachs disease, gangliosidosis, Sandhoff disease, Farber disease, sialidosis, Niemann–Pick disease, metachromatic leukodystrophy, and galactosialidosis.1, 6, 7, 8 In our cases, all detailed examinations and laboratory analysis were negative for metabolic diseases, intellectual impairment, psychomotor retardation, and musculoskeletal diseases. Therefore, we could not detect any hereditary metabolic diseases.

CRS at the macular can be seen in CRA occlusions.1, 9, 10, 11 In our cases, only the oldest sibling had amblyopia and its related eye deviation. The ophthalmological findings (except bilateral PMLO and CRS appearance) of the other siblings were within normal limits. None of them had history of sudden visual loss, trauma, or ocular surgery (except strabismus surgery of the oldest sibling).

Toxicity to drugs and gases can cause CRS at the macula, and these include dapson, methanol, quinine, and carbon monoxide.1, 3, 4

When the literature is observed in the etiopathogenesis of CRS, hereditary metabolic storage disorders,1, 6, 7, 8 CRA occlusion,1, 9, 10, 11 drugs and gases toxicities1, 3, 4 have a role. We performed required laboratory tests and systemic examination for storage disorders and found out them in normal limits in our patients. We performed detailed ocular examination that includes visual acuity, IOP, slit lamp, and fundus examination and fundus fluorescein angiography for CRA. We found out all of them in normal limits except on sibling who has exotropia and amblyopia. We did not have any findings about drugs and gas toxicity. For this reason, we evaluated CRS in our patients as isolated.

Isolated CRS at the macula has been infrequently reported in the literature.12 However, we have not encountered a case with co-occurrence of CRS at the macula and PMLO without any accompanying ocular and metabolic diseases in the literature.

In conclusion, this case is unique due to co-occurrence of CRS at the macula and PMLO without any accompanying ocular or metabolic diseases in all four siblings.