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Optimisation procedure after corneal intrastromal implantation surgery (CISIS) for keratoconus

Session Details

Session Title: Cornea Surgical II

Session Date/Time: Wednesday 09/10/2013 | 08:00-10:30

Paper Time: 08:18

Venue: Forum (Ground Floor)

First Author: : A.Daxer AUSTRIA

Co Author(s): :                  

Abstract Details

Purpose:

Every single Keratoconus case reflects a complex biomechanical situation which requires an individual consideration and treatment strategy. Nomograms for intra-corneal implants are more or less complicated to cover a broad range of individual cases. Nevertheless, such nomograms can never predict the optimal implant in every single case. Therefore, a simple postoperative enhancement procedure including a related theory and decission criteria should be considered as an integrated part of this kind of therapy. MyoRing intra-corneal implant (DIOPTEX GmbH, Austria) is an Intra Corneal Complete Ring (ICCR) for implantation into a corneal pocket. Intra Corneal Ring Segments (ICRS) offer one degree of freedom (DOF) for postoperative intervention while ICCR offers the surgeon access to all 3 theoreticall possible DOF to optimize the postoperative result. The purpose of this study is whether the theory and decission making strategy for the presented postoperative optimisation procedure in cases of MyoRing treatment for Keratoconus can improve the results compared to applying the standard nomogram.

Setting:

Keratoconus Center in Austria

Methods:

Twenty-five eyes of 20 patients suffering from Keratoconus have been treated by MyoRing implantation into a corneal pocket. Corneal pockets of 9mm in diameter at 300 microns depth have been created using the PocketMaker Microkeratome (DIOPTEX GmbH, Austria). Sixteen patients were male and 4 were female. The age of the patients ranged from 20 years to 42 years (mean 26 years). Eight eyes suffered from mild (average central K-reading (ACK) < 48 diopters (D)), nine eyes from moderate (48 D < ACK < 52 D) and eight eyes from advanced (ACK > 52 D) Keratoconus. Main criteria for success was patient satisfaction and uncorrected distance visual acuity (UDVA). A further decission criterion for the postoperative enhancement strategy was a particular topographic pattern criterion in the postoperative tangential map. Postoperative follow-up ranged from 6 to 52 months (mean 34 months).

Results:

Three patients (3 eyes) were not satisfied after final examination. One of these patient had an extremely advanced keratoconus (ACK preop 68D) who finaly received karatoplasty. One of them had an unaffected fellow eye with 20/20 UDVA who did not use the treated eye in the visual process despite 12 line improvement in UDVA, and one suffered from non-adaptable glare and night vision problems despite 13 lines improvement in UDVA. After initial implantation the average improvement in UDVA was 6.4 lines. Eight eyes out of the 25 eyes treated (32%) received a postoperative optimisation procedure either by exchanging the implant for one with another dimension or by adapting the functional centration of the implant within the pocket according to a defined postoperative tangential map criterion. The functional centration in some cases differ from an anatomical centration. After optimisation the average improvement in UDVA in the entire group (25 eyes) was 10.5 lines. No intraoperative or postoperative complications were seen.

Conclusions:

To achieve the best possible result after CISIS in every given keratoconus case the option of postoperative optimisation following a related theory and decission making should be considered as an integral part of keratoconus treatment with MyoRing implantation into a corneal pocket. One can expect that in 20% to 30% of the cases a simple enhancement procedure after applying the standard nomogram can further improve the postoperative results to excellent levels. The results after initial MyoRing implantation according to the standard nomogram show more than 6 line improvement in UDVA. This result is better, however, roughly comparable with the results achieved after ICRS treatment (4 to 5 lines). The presented MyoRing optimisation method is based on a defined postoperative decission making strategy which allows improvement of up to 18 lines in UDVA in single cases and an average improvement in UDVA of more than 10 lines as well as a big number of highly satisfied patients.

Financial Interest:

... has significant investment interest in a company producing, developing or supplying product or procedure presented