Sir,

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder due to defect in DNA repair mechanism. Corneal involvement is seen in 17% of cases.1, 2 Outcomes of penetrating keratoplasty (PKP) are usually poor.1, 3 We report the youngest child with XP to have PKP with the longest follow-up till date.

Case report

A 6-year-old male child of consanguineous parents was seen with a clinical diagnosis of XP. His visual acuity in both eyes (OU) was hand movements close to face. The lid position, congruity, and tear meniscus height were normal in OU. Examination under anaesthesia revealed full-thickness corneal scarring (Figure 1a) with calcific degeneration and normal anterior chamber in OU.

Figure 1
figure 1

Clinical pictures showing (a) right corneal scarring with calcific plaque-like degeneration (white arrows ) and generalised corneal opacification (white star) before PKP, (b) showing clear graft in left eye and (c) right eye at the most recent follow-up.

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The patient underwent an uneventful PKP in his left eye (OS) in June 2004 and right eye (OD) in April 2005. Subsequent postoperative follow-ups were uneventful, and dexamethasone eye drops were tapered to once daily over 6 weeks. Suture removal was done by 12 weeks after surgery. He developed posterior sub-capsular cataract in OU for which he underwent lens aspiration in September 2007 (OD) and January 2008 (OS). His both eyes were highly myopic and hence intraocular lens was not implanted.

At the most recent visit, May 2010, on crowded logMAR, the patient could manage 0.8 at 33 cm using +0.50DSph/−2.50DCyl × 135 correction with OD and 0.8 at 70 cm using −2.5DSph/−0.50DCyl × 135 correction with OS. With OU, he could read N36 at 33 cms. The grafts in both eyes of the patient were clear (Figures 1b and c) and intraocular pressures were within normal limits.

Comment

The median age of onset of ocular manifestations has been reported to be 4 years.1 Literature shows PKP done in only two cases in children (Table 1).4 These two cases had an early graft failure and required a repeat PKP for visual rehabilitation.4

Table 1 Literature review of children with xeroderma pigmentosum who had penetrating keratoplasty
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Amblyopia due to stimulus deprivation in this case has resulted in low vision. Nevertheless this child can now read enlarged print, navigate in unfamiliar surroundings, and attend a normal school with educational support. This child’s grafts may have done well due to healthy lid and tear film, which in part may have been due to a shorter duration of the disease process prior to surgery. Hence, retaining healthy eyelids and in turn ocular surface will increase the longevity of corneal grafts even in chronic diseases such as XP.