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Editor,—Arcus lipoides corneae usually occurs bilaterally and symmetrically.1 Pronounced unilateral arcus lipoides corneae occurs in atrophic eyes, less marked with relative ocular hypotension2-4 or contralateral carotid artery stenosis.5-7 We report on a patient with unilateral arcus lipoides in the normal eye sparing the other one with Sturge–Weber syndrome.
A 33 year old patient showed a left sided secondary juvenile open angle glaucoma due to Sturge–Weber syndrome. The glaucoma diagnosed at the age of 10 months with a maximum intraocular pressure (IOP) of 40 mm Hg had been treated twice by diathermy of the ciliary body, and once by trabeculectomy during the first 6 years of life. Since then, the IOP has ranged between 16 and 20 mm Hg in the left eye, constantly being 4–6 mm Hg lower in the right eye.
A facial haemangioma involving the first and second branch of the facial nerve had been treated with radiotherapy after birth (Fig 1). There was no history of neurological deficits or epilepsy. Apart from intermittent hypercholesterolaemia up to 260 mg/dl, the young man's medical history was unremarkable.
Visual acuity was 20/15 right eye and 20/30 left eye, intraocular pressure 16 mm Hg right eye and 20 mm Hg left eye. The right eye disclosed a definite yellow-whitish arcus lipoides extending through the entire corneal thickness, separated from the limbus by a clear zone (Fig 2A). The arcus was more pronounced superiorly and inferiorly than in the medial and lateral quadrant. Apart from the arcus lipoides, the right eye did not reveal any abnormalities.
No arcus lipoides could be detected in the left eye (Fig 2B). The eye showed increased episcleral vascularisation. The optic disc presented with moderate glaucomatous disc change (optic disc size 3.0 mm, cup/disc ratio 0.78).
Arcus lipoides corneae is known to be usually associated with hyperlipoproteinaemia, especially type IIa and IIb, but may occur without predisposing factors.1 Histologically, it mainly consists of extracellular deposits of cholesterol, phospholipids, and triglycerides in stroma, Bowman and Descemet membrane.8Generally, it is developed bilaterally and symmetrically.1Single cases of unilateral arcus lipoides corneae were reported in eyes with absolute or relative ocular hypotension,2-4 or in patients with contralateral carotid artery stenosis.5-7
Our patient presented with a narrow, but clearly recognisable arcus lipoides which occasionally can occur in younger people, even in the absence of marked hyperlipoproteinaemia.1
In earlier reports,8 it was suggested that vascular congestion and increased vascular permeability of limbal blood vessels might possibly be involved in the development of unilateral arcus lipoides. Analogously to cases of absolute ocular hypotension, one could assume that in our patient, the relative hypotension in the right eye with consecutively relatively higher blood supply may have facilitated the lipid deposition in the cornea, whereas the development of arcus was prevented by the higher IOP in the left eye.
In our opinion, this case implies that unilateral arcus lipoides corneae can occur in morphologically normal eyes with solely relative ocular hypotension.
Supported by Deutsche Forschungsgemeinschaft, Bonn, Germany (SFB 539, “Glaukome einschliesslich Pseudoexfoliationssyndrom”).