Sir,

Case report

A 50-year-old gentleman presented to eye casualty with a 1 week history of reduced vision and headache above his left eye. He had a left corneal graft for keratoconus in 1988 and had not been seen by us since 1993 when his aided vision was 6/9 right 6/36 left.

On examination, his aided visual acuity was 6/12 right and hand movements left. On the right side, there was a mild keratoconus. On the left side there was severe oedema of the corneal graft and an obvious split in Descemet's membrane in the graft. The host cornea was unaffected (Figure 1).

Figure 1
figure 1

Appearance on presentation.

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A diagnosis of hydrops affecting the corneal graft was performed. He was treated with intensive topical steroid as the differential diagnosis was of graft rejection. However, the steroid drops were quickly tailed down as they did not seem to improve the clinical course and we were confident with our diagnosis.

One month later, the hydrops had resolved leaving only minimal scarring and slightly increased graft thickness (Figure 2). His visual acuity was 6/12 right 1/36 left with glasses.

Figure 2
figure 2

Appearance at one month.

Full size image

Comment

Keratoconus is a progressive, bilateral, non-inflammatory degenerative condition, leading to increasing irregular astigmatism. Keratoplasty is indicated when other treatment methods such as glasses, contact lenses, INTACS or DALK either fail or are not suitable. It has been shown that keratoconus can recur in a graft in 11.7% cases, with a mean time to recurrence of 17 years.1

Hydrops is caused by a break in Descemet's membrane and is believed to occur in 2.6–2.8% cases with keratoconus.2 The differential diagnosis for hydrops occurring within a graft includes endothelial rejection but in this case the split in Descemet's membrane was clearly seen. Hydrops has been reported previously in a corneal graft where the hydrops occurred in the host tissue or in the host-graft junction and extended into the corneal graft.3, 4 However, we believe that this is the first reported case, in which corneal hydrops has been found to occur purely in a corneal graft.