Manual Dalk: Surgical Management Of An Advanced Keratoconus Case With Central Stromal Scarring And Important Corneal Ectasia

To present the surgical management of an advanced keratoconus with stromal scarring, in a young male patient with asymmetric evolution of the disease, complicated with intraoperative Descemet membrane microperforation during the deep anterior lamellar keratoplasty (DALK) procedure.

Clinical Emergency Eye Hospital Bucharest

We report the case of an 18 year old patient, known with asymmetric bilateral keratoconus  who presented in our clinic for progressive loss of visual acuity and photophobia. He had previously been diagnosed with stage 2 keratoconus in the right eye, and stage 4 keratoconus in the left eye. 

Best corrected visual acuity was 0.9 in the right eye and counting fingers in the left eye. Slit lamp examination highlighted a mild paracentral corneal ectasia, with mild scarring following the CXL procedure in the right eye and paracentral corneal ectasia, Fleischer ring, superficial stromal scarring and deep anterior chamber in the left eye. Munson and Rizzuti's signs were positive. Corneal topography of the left eye showed modified parameters: mean simK 74D, thinnest pachymetry 309µm.

Manual DALK was performed in accordance with the corneal thickness map. Intraoperative OCT was a valuable tool for the assessment of the residual stromal bed. During the procedure, a small peripheric microperforation occurred, proper managed intraoperatively.

At the 1-month follow up, autorefractometry results were -0,5dsf -1.75 cyl 50 deg, with a BCVA of 0.6. 

At the 3-months followup, inferior suture repositioning was needed due to a decrease in visual acuity caused by subsequent laxity in the sutures in accordance with the modified topographical map which revealed mild inferior ectasia. One month after this procedure autorefractometry  results were -1.5 dsf -4d cyl 120 deg, K-max of 48 and BCVA of 1. 

The medical condition, its evolutionary stage, and the patient's age collectively indicated the necessity for performing DALK.  Despite the presence of stromal scarring, significant ectasia, and variable corneal thickness, meticulous dissection enabled the successful execution of a descemetic DALK (TALK ).  In this case the emphasis should be on the total exposure of Descemet's membrane, after the dissection of stromal bed, keeping in mind the Descemet’s lack of resistance that can lead to microperforations.

The refractive outcomes observed postoperatively are remarkable for two reasons: a good graft dimension and a very thin residual bed, particularly in our case where we achieved an anatomical separation up to the Descemetic plane.