The Importance Of Pachymetry Mapping After Deep Anterior Lamellar Keratoplasty

To emphasize that pachymetry mapping is an essential diagnostic tool after deep anterior lamellar keratoplasty (DALK) to detect asymmetry in the graft thickness, in cases that the expected visual acuity is not achieved.

Ophthalmology department, Joan XXIII University Hospital. Tarragona, Spain.

We present a 26-year-old woman with keratoconus. Visual acuity (VA) of the right eye (RE) was counting fingers that improved to 0.2 with pinhole. The ophthalmic examination of RE revealed Vogt's striae, Fleischer's ring, and Munson's sign. The corneal topography reveled a central keratoconus, Kmax 51 D and pachymetry of the thinnest area 480 μm. Visual acuity did not improve with rigid gas permeable contact lenses. The patient underwent DALK with big bubble technique. No relevant postoperative complications occurred. After suture removal, VA was 0.2 that improved to 0.3 with pinhole or glasses (40º -4.00 -1.25). The graft was clear, and the ophthalmic examination was normal (intraocular pressure, fundoscopy and macular optical coherence tomography). A Scheimpflug camera tomography with pachymetry mapping was performed, which revealed the presence of asymmetry in the graft thickness. The nasal corneal area thinning was 722 μm and the temporal corneal area thinning was 610 μm, which means a difference of 112 μm. The graft thickness asymmetry was assumed to be due to an inadvertent offset of the graft, when preparing it during the surgery. The patient underwent DALK for a second time. After suture removal, the pachymetry mapping showed regularity in thickness, and final visual acuity was 0.7 (50º -3.00). 

Corneal Scheimpflug camera tomography with pachymetry mapping is essential for the postoperative assessment of DALK. In this case, asymmetry in the graft thickness was the reason why the expected visual acuity was not achieved and the pachymetry mapping was a key element for diagnosis.