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Letter

Retention of an anterior chamber IOL versus IOL exchange in endothelial keratoplasty

Chen, Edwin S. MD1; Terry, Mark A. MD2; Shamie, Neda MD2; Phillips, Paul M. MD3; Friend, Daniel J. MS4

Author Information
Journal of Cataract & Refractive Surgery: April 2009 - Volume 35 - Issue 4 - p 613
doi: 10.1016/j.jcrs.2008.12.029
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We wish to clarify the citation of our abstract (E.S. Chen, MD, et al., “Endothelial Keratoplasty with Retention of an Anterior Chamber IOL: Technique and Endothelial Survival,” presented at the annual meeting of the American Academy of Ophthalmology, New Orleans, Louisiana, USA, November 2007) by Wylęgała and Tarnawska1 in their article about Descemet-stripping endothelial keratoplasty (DSEK) with intraocular lens (IOL) exchange. In the “Discussion,” Wylęgała and Tarnawska advocate the advantages of IOL exchange over retention of an anterior chamber IOL, partly because of the intraoperative difficulty secondary to reduced anterior chamber volume. They state that some authors advocate retention of an anterior chamber IOL and cite our abstract.

Our study of 16 eyes having endothelial keratoplasty with retention of an anterior chamber IOL used the deep lamellar endothelial keratoplasty technique (DLEK), not DSEK. In the study, we found that although there was no increased incidence of dislocation (5%) or iatrogenic graft failure (0%) if an anterior chamber IOL was retained, there was a statistically significant difference in endothelial cell loss at the 6- and 12-month postoperative time points compared with DLEK with a posterior chamber IOL (37% versus 29% at 6 months, P = .031; 44% versus 34% at 12 months, P = .05). We provided 5 possible reasons for this increase in postoperative endothelial cell loss, including (1) increased tissue manipulation, (2) reduced depth of the anterior chamber, (3) presence of anterior chamber hardware, (4) more difficult air-bubble management, and (5) intermittent postoperative IOL touch. To date, there have been no similar published series describing short-term postoperative complications or endothelial cell loss in DSEK with retention of an anterior chamber IOL. Our conclusion was that performing endothelial keratoplasty with a DLEK technique in the presence of an anterior chamber IOL was associated with certain drawbacks and that the surgical decision to retain or exchange an anterior chamber IOL should be made by each surgeon on a case-by-case basis after weighing these risks against those of IOL exchange, including prolonged surgery, iris/ciliary body tears, and retinal detachment.

Retention of an anterior chamber IOL in DLEK is distinct from that in DSEK in many ways, which relate to the differential use of a deep lamellar dissection versus stripping Descemet membrane to prepare the recipient. First, DLEK includes a resection of the inner host cornea and thereby increases the depth of the anterior chamber. This provides greater room in which to manipulate the endothelial graft. Second, presence of an anterior chamber IOL is almost always accompanied by a history of vitrectomy and loss of an intact lens–iris diaphragm, which makes retention of a postoperative air bubble more difficult. One of the primary techniques used by DSEK surgeons to reduce the incidence of dislocation is the use of a postoperative intracameral air bubble,2,3 which is not necessary for adhesion of the disk in DLEK. Greater difficulty in retaining a postoperative air bubble would be expected to increase the likelihood of dislocation. Third, it has been theorized that the cut stromal fibrils on the recipient cornea created by the deep lamellar dissection of DLEK assist in postoperative adhesion of the donor graft. Addition of peripheral stromal scraping to recreate the rough surface of DLEK peripherally in DSEK patients has been demonstrated to significantly reduce dislocation.3 Lack of these stromal fibrils in DSEK may also increase the likelihood of dislocation. These last 2 points are particularly important in the retention of an anterior chamber IOL because if the graft does dislocate, it would fall on an anterior chamber IOL rather than the iris surface, causing extensive damage to the donor endothelium. This would be expected to reduce the lifespan of the graft or possibly result in an iatrogenic graft failure.

We therefore agree with Wylęgała and Tarnawska that IOL exchange is preferable to retention of an anterior chamber IOL in endothelial keratoplasty by the Descemet-stripping technique. For these reasons, we believe DLEK still has a place in the treatment of endothelial failure in patients in whom IOL exchange is not a good option.

REFERENCES

1. Wylęgała E, Tarnawska D. Management of pseudophakic bullous keratopathy by combined Descemet-stripping endothelial keratoplasty and intraocular lens exchange. J Cataract Refract Surg. 2008;34:1708-1714.
2. Price FW Jr, Price MO. Descemet's stripping with endothelial keratoplasty in 200 eyes; early challenges and techniques to enhance donor adherence. J Cataract Refract Surg. 2006;32:411-418.
3. Terry MA, Hoar KL, Wall J, Ousley P. Histology of dislocations in endothelial keratoplasty (DSEK and DLEK); a laboratory-based, surgical solution to dislocation in 100 consecutive DSEK cases. Cornea. 2006;25:926-932.
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