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Homoplastic ALK.

A NEW procedure called homoplastic automated lamellar therapeutic keratoplasty (HALTK) may be the gateway to restoring corneal clarity and provide a useful alternative to penetrating keratoplasty (PK) and phototherapeutic keratectomy for anterior corneal opacities.

Presenting the early results of his experience with the procedure at a meeting of cornea specialists, Sheraz Daya MD said the numerous potential advantages of this approach include rapid recovery with minimal follow-up, early refractive stability and the possibility of achieving good results from subsequent Lasik procedure.

In his pilot study, 32 eyes of 31 patients have been treated since 1997. The average age was 49 years, ranging from 23 to 87. The most common indications for surgery were anterior stromal opacities secondary to Reis-Buckler’s dystrophy (14 eyes), post-refractive surgery haze (seven eyes), and anterior stromal dystrophy (three eyes). The average follow-up was 19.6 months, with a range of three to 60 months.
HALTK uses a Lasik microkeratome to create a thin resection which is user-defined (between 160 and 200 microns). The first step is a resection of the recipient lamella flap with retention of the flap.

A whole fresh donor eye is then inflated with BSS through the optic nerve. After suction is performed and tonometry checked, the donor flap is resected. The lamellar flap is then placed on the recipient eye and allowed to dry.

The keratomes used in the present study were the automated corneal shaper (Chiron) for 16 eyes (160, 240, 300 micron plate) and the Hansatome (Bausch & Lomb) for another 16 eyes (200 micron plate).
The surgeons placed sutures in 21 eyes (66%), and removed them between one and six weeks after the procedure. Maxidex and chlotamphenical once a day were administered for one month in the first 16 cases. The surgeons now use only FML (Fluorometholone 0.1% one drop a day for the first year, he noted.

After one year, 83% of patients showed improvement in UCVA and BCVA. UCVA at two years was 20/40 or better for 13 patients (62%), while only 16 (36%) reached that level of vision after one year. As time goes by these patients’ vision improves steadily, Dr Daya remarked.

The improvement in BCVA was fast, sometimes as early as one month following the procedure, with 59% of patients able to read 6/12 or better after that period. At one year, 16 patients (69%) saw 20/40 or better. After two years, 14 saw 20/40 or better (93%) and 85% saw 20/30 or better. Only 7% of patients had a BCVA of 20/50 or worse at two years.

“Initially we were concerned about a small loss of lines of vision, but the results clearly improved with time. After two years 16 patients (69%) had gained two or more lines of vision, and 94% had gained one or more. Cylinder angle and elevation maps (Orbscan) were similar before and after the operation,” he reported.

The team performed Lasik in four eyes after undergoing HALTK, with good results. The average time between both procedures was 15 months. Following Lasik, UCVA was 20/25 or better in all eyes and BCVA was 20/20 in all eyes.

Three eyes suffered rejection within eight months of surgery. Two were associated with epithelial reactions and one had epithelial and stromal reactions. They were successfully treated with intensive topical steroids (Dexamethasone 0.1%).
Flap-related complications occurred in two patients. A diabetic had a persistent epithelial defect and required flap replacement. There were also three visually insignificant epithelial ingrowths and two cases of monocular diplopia.

“HALTK succeeded in restoring corneal clarity in all cases. This is a useful alternative to penetrating keratoplasty and phototherapeutic keratectomy for anterior corneal opacities. It is a great technique, but you need to warn your patients that it is going to take some time for their vision to improve,” Dr Daya stressed.

Sheraz Daya MD, FACP, FACS, FRCS (Ed)
Corneoplastic Unit and Eye Bank, East Grinstead, UK
Email: sdaya@centreforsight.com