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Sonomed, STAAR Surgical, Alcon

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Presentation on theme: "Sonomed, STAAR Surgical, Alcon"— Presentation transcript:

1 Sonomed, STAAR Surgical, Alcon
Sizing Nomogram for ICL Vault Determination Using Sulcus-to-Sulcus Measurements Obtained with High Frequency Ultrasound Robert Rivera MD ASCRS Symposium & Congress Boston 2010 The author has received research support, travel support, honoraria and consulting fees from the following: Sonomed, STAAR Surgical, Alcon

2 Sizing of the Visian ICL
ICL size chosen for implantation is based on white-to-white (WTW) measurement US FDA Clinical Study was based on WTW FDA approval based on WTW Assumption was that surface WTW measurement would closely follow sulcus-to-sulcus (STS) length Subsequent results and studies have shown this is not a valid assumption Note that UBM technology was not available in earlier days of ICL implantation; WTW was the best approximation available

3 Sizing of the Visian ICL
17% of patients in the US clinical trial did not have optimal vault ( µ) Gonvers, et al, 2003 75 ICL cases, 27% cataract rate, all cataracts had vaults less than 90 µ Choi and Chung, 2007 ICL length determined by UBM achieved ideal vault compared to conventional WTW 100% of UBM group had ideal vault after 6 months, compared to 52.9% in the WTW group

4 Ideal Vault Truly “ideal” vault would be 500 µ
Inadequate vault defined as <90 µ (Gonvers 27% cataract rate = vaults less than 90 µ) Excessive vault defined as >1000 µ (Choi, Chung, Chung & Chung) “Good” vault range µ

5 Development of a Sizing Nomogram
Retrospective Study 73 eyes of 48 subjects with STS and vault measurements taken on Sonomed VuMax II Matamoros regression equation Modified with input from experienced ICL and Sonomed users Outcome analysis used to generate a spreadsheet of ideal ICL length, based upon STS measurements

6 Multi-Center Prospective Analysis of UBM for ICL Sizing
Prospective multi-center trial Sonomed VuMax II used to image sulcus images Investigators: David Brown, MD Paul Dougherty, MD Stephen Lane, MD Robert Rivera, MD David Schneider, MD John Vukich, MD

7 Prospective Study 61 eyes of 61 subjects Age 21-45
Average myopia treated –7.6D No history of previous refractive surgery IRB approval and informed consent obtained 1 eye excluded Wrong length ICL placed Nomogram suggested 13.2mm 12.6mm ICL implanted Subject had 0 vault

8 ICL Vault Avg: 344 Min: 93 Max: 952

9 Results of STS vs. WTW Methods
If the FDA label WTW method of sizing ICLs was used, 65% of cases would have received a different size ICL than the STS Method, potentially requiring explantation in a significant number of patients If the improved PreVize Optimized WTW method of sizing ICLs was used, 34% of cases would have received a different size ICL than the STS Method Poor correlation (R2 value) between STS and ATA (58%); STS and WTW (46%)

10 Conclusions Using our Sonomed study nomogram derived from STS Measurements, no cases fell within an unacceptable range of ICL vault compared to a reported 15%-20% of cases based upon WTW measurements Average Vault was 344 µ (range ) WTW methods would have resulted in different sized ICLs in 34% to 65% of cases compared to the STS method

11 Conclusions Further refinement of nomogram may allow improvement in higher and lower ranges of vault UBM STS measurements are far superior to WTW for the purposes of ICL selection with a far greater margin of safety Despite the FDA label, surface WTW measurements may lead to incorrect ICL selection in a significant percentage of patients In our opinion, careful systematic UBM STS should become the standard of care in ICL size selection

12 Thank You

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