Sir,

Corneal oedema and bullous keratopathy are known complications of cataract surgery and can occur following an uncomplicated procedure.1 Various predisposing factors for pseudophakic bullous keratopathy include pre-existing corneal endothelial disease such as Fuchs dystrophy1 and use of anterior chamber and iris-supported lenses.2 Birth trauma to the cornea is known to cause a decrease in the density of endothelial cells.3 This may cause corneal oedema at birth or at any later stage.3 However, we are not aware of any reported cases of corneal oedema following cataract surgery in such eyes. We recently had a patient with a peripheral Descemets membrane rupture due to birth trauma who developed pseudophakic bullous keratopathy following uncomplicated phacoemulsification.

Case report

A 76-year-old male patient presented with diminution of vision in the right eye due to progressive cataract. His best-corrected visual acuity was 6/12 in the right eye and 6/9 in the left eye. Preoperative assessment revealed a right corneal curvilinear opacity, 2 mm from the periphery, at the level of the Descemets membrane and endothelium (Figure 1). There was no other abnormality in either eye. Retrospectively, birth history revealed a forceps-assisted delivery. There was no depression on the contra lateral occipital region, a sign that may be present in patients having corneal birth trauma.3 Uncomplicated phacoemulsification through a superiorly placed clear corneal incision with in-the-bag implantation of an acrylic lens was performed. The total ultrasound time was 71.03 s and the average ultrasound power used was 8%. Significant corneal oedema was noted on the first post-operative day and the best-corrected visual acuity was 6/36. A week later the cornea developed some bullae. On the last postoperative visit, 5 months after the surgery, the best-corrected visual acuity was 6/12, with some improvement in the corneal condition. Specular microscopy of the fellow eye revealed normal endothelial cell count and morphology. The corneal oedema made it impossible to perform specular microscopy of the affected eye.

Figure 1
figure 1

A curvilinear Descemet's membrane split-evidence of corneal birth trauma. (Inset: magnified view under focal illumination.)

Full size image

Comment

Our patient had an unusual corneal pathology, clinically suggestive of the Descemets membrane rupture. In the absence of any other corneal findings, the history of forceps-assisted delivery makes birth trauma the most likely cause although it can only be proven by a histological study.4 It is also not possible to prove that this eye had a low endothelial cell count preoperatively. However, it is known that corneal birth trauma causes endothelial cell loss3 and can lead to late endothelial decompensation in adult life.5 This case highlights the risk of cataract surgery in an eye with a cornea compromised by birth trauma, a risk we failed to recognise preoperatively. We suggest that a patient with signs suggestive of corneal birth trauma should have an endothelial cell count before undergoing any intraocular procedure. A low endothelial cell count will be an objective indicator of the increased risk of cataract surgery in such a patient. Intraoperative measures such as the soft shell technique6 should then be employed to reduce the risk of postoperative bullous keratopathy.