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Editor,—Fleck corneal dystrophy is a rare, stable, and usually asymptomatic condition. It is characterised by numerous small white flecks scattered in all layers of the stroma from the centre to the periphery. François and Neetens described the condition for the first time in 19571 and called it “hérédodystrophie mouchetée” while Streeten and Falls reported two families with the same condition in 19612 and translated the name to hereditary fleck dystrophy of the cornea. Only a few families have been reported in the literature and the dystrophy is thought to be rare, not well recognised, and easily missed by the ophthalmologist. We report on three affected members of an English family and comment on the differences with other described cases.
A 65 year old white man with no ocular history attended the eye casualty department for the treatment of a small right traumatic corneal abrasion. His best corrected visual acuities were 6/5 on the right and 6/6 on the left. Slit lamp examination revealed numerous bilateral small grey-white fleck-like opacities scattered in his corneal stroma at all levels, with variable density and affecting both the central and peripheral cornea (Fig 1). There was clear intervening stroma between the lesions and associated anterior crocodile shagreen bilaterally. His epithelium and endothelium appeared normal and his corneal sensation was reduced.
Other members in three generations of his family were examined. The patient's son and one sister also had corneal fleck dystrophy bilaterally as shown in the family pedigree (Fig 2).
The affected members were asymptomatic and had normal vision. The lesions were identical and followed a similar distribution in all three patients with a lesser density in the patient's sister who also had decreased corneal sensation and associated anterior crocodile shagreen. On the other hand the patient's son had prominent corneal nerves but normal corneal sensation. There were no other associated ocular or systemic abnormalities.
This is the first English family with corneal fleck dystrophy reported in the literature. Since the original description by François and Neetens1 there have been a number of reports establishing the dominant inheritance and the variable expressivity of this benign condition.2-4 Only one family reported by Gillepsie and Covelli5 showed autosomal recessive inheritance with no apparent difference in phenotypic expression. According to the original description, the subtle, round, oval, or wreath-like lesions have sharp borders and vary in size and number. All levels of the stroma are affected with the lesions extending to the limbus.1Asymmetrical involvement of the two eyes is common and unilateral involvement has been noted.2 5 6 Patients are usually asymptomatic and a very few report occasional photophobia.7
The pathogenesis of this dystrophy remains obscure. Impaired or deficient hydrolytic enzymes within the keratocytes might be responsible for the abnormal accumulation of intracellular mucopolysaccharide and lipid.8-10 Extensive investigations failed to detect an underlying systemic metabolic abnormality7 and this condition might represent a localised storage disorder limited to the cornea and confined to the keratocytes.
While our cases of hereditary fleck dystrophy are similar to those previously reported, the only notable difference is the presence of associated anterior crocodile shagreen in two patients and prominent corneal nerves in another. Because anterior crocodile shagreen is usually bilateral and seen in the elderly, its association with fleck dystrophy in two patients is likely to be a concurrent event due to chance only. On the other hand a familial and dystrophic form of posterior crocodile shagreen has been described as central cloudy dystrophy by François11 and found to be associated to fleck dystrophy in the same patient12 and in different members of the same family.1 5 Decreased corneal sensation initially reported by Bindorf and Ginsberg in 19726 is only present in two of our patients. This variable association has also been confirmed in other reports.2 4 8
The importance of fleck dystrophy lies in its recognition as a non-progressive and benign condition compared with other inherited but progressive stromal dystrophies. The diagnosis should not be difficult in most cases. Its asymptomatic nature together with the distinctive forms and distribution of the stromal opacities can differentiate it easily from other known dystrophies such as Groenouw's granular dystrophy.