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The presence of a retrocorneal membrane following an uneventful keratoplasty is a known entity.1,2 While the inflammatory membranes usually disappear with the use of topical steroids3 a YAG laser treatment has been used to make an opening in the opacified retained membrane. We describe a new technique of removal of retained Descemet’s membrane using trypan blue dye.
A 27 year old man underwent penetrating keratoplasty in his left eye for congenital hereditary endothelial dystrophy (CHED). The host cornea was initially trephined to 90% of the corneal depth with a 7.5 mm trephine (Storz Ophthalmics, St Louis, MO, USA). The anterior chamber was entered with a blade and the host cut was completed with corneal scissors. An 8 mm donor button was anchored with 16 interrupted sutures (10-0 monofilament nylon). On the first postoperative day, slit lamp biomicroscopy revealed a retained Descemet’s membrane and a supernumerary anterior chamber. The graft was clear with a best corrected visual acuity (BCVA) of 20/40.
At 1 week, an additional inflammatory membrane was detected between the retained Descemet’s membrane and iris at 6 o’clock position extending from the inferior margin up to the lower third of the anterior chamber (Fig 1). The inflammatory membrane did not resolve with increased frequency of topical steroid and at 4 weeks we decided to excise these membranes.
The 10 o’clock and the 11 o’clock sutures were removed and the graft host junction was separated. Under air, 0.1 ml of 0.1% trypan blue (Vision blue, DORC, Netherlands) was injected over the host’s retained Descemet’s membrane and was left in contact with it for 10 seconds and then washed out. Both retained Descemet’s membrane and inflammatory membranes were stained with the dye. The inflammatory membrane was first removed using a Utrata forceps. Subsequently, a small flap was created in the retained Descemet’s membrane and the membrane was torn in a circular fashion (Fig 2). The anterior chamber was reformed and sutures were reapplied. On the first postoperative day the graft was clear, the anterior chamber was well formed, and there was no retrocorneal membrane.
A 26 year old man underwent penetrating keratoplasty in his right eye for CHED with the same surgical technique and graft size as in first case. On the first postoperative day, a transparent retained Descemet’s membrane along with formation of a supernumerary chamber was detected on slit lamp biomicroscopy. The graft was clear with no active inflammation in the anterior chamber and BCVA was 20/40.
Based on our experience of case 1 regarding the development of inflammatory membrane, we decided to excise the retained Descemet’s membrane at 1 week using the same technique. Postoperatively, slit lamp biomicroscopy did not reveal any evidence of supernumerary chamber or retrocorneal membrane.
Postoperatively, the patients received 2 hourly 0.1% betamethasone sodium phosphate eye drops, 0.3% ciprofloxacin eye drops four times daily and preservative-free artificial tears eye drops four times daily. At 2 months of follow up, the grafts were clear with a single anterior chamber and the visual acuity of 20/40 was maintained in both the eyes.
Both these cases with retained host Descemet’s membrane following penetrating keratoplasty were that of CHED. In these cases, longstanding stromal oedema may cause loosening of the attachment of the Descemet’s membrane and predispose its separation from the overlying stroma as has also been reported in a case of interstitial keratitis.4 Hence, inadvertent, incomplete trephination of such oedematous corneas may cause retention of the host Descemet’s membrane. Although both the patients had good vision and the grafts and retrocorneal membranes were clear, we decided to excise these membranes as an inflammatory membrane started growing in the first case. We thought that the host’s retained Descemet’s membrane is acting as a scaffold and further growth of inflammatory membranes may jeopardise the graft.
Trypan blue is commonly used to stain the anterior lens capsule for capsulorhexis in cataract surgery.5 As both lens capsule and Descemet’s membrane are basement membranes, we attempted to stain the retained Descemet’s layer with trypan blue to enhance its visibility during the surgery. In both the cases an optimal staining of the membranes helped in achieving a controlled circular tearing of the membrane without affecting graft clarity.
We called our technique of dye assisted removal of retained Descemet’s membrane “descemetorhexis” as the retained Descemet’s membrane were torn in a circular fashion at the graft-host junction.
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