Objective vs Subjective Vault Measurement After Myopic Implantable Collamer Lens Implantation

PURPOSE: To evaluate the relationship between subjective measurements of vault and objective values measured with Visante optical coherence tomography (OCT) in eyes receiving an implantable contact lens (ICL) for myopia correction. DESIGN: Observational cross-sectional study. METHODS: SETTING: Fernandez-Vega Ophthalmological Institute, Oviedo, Spain. PATIENTS: Four hundred and fifty-two eyes from 246 patients were elected to be implanted with a Visian ICL V4 (STAAR Surgical Inc, Monrovia, California, USA). OBSERVATION PROCEDURES: Subjective and objective measurements of vault after implantation of ICL. MAIN OUTCOME MEASURES: Subjective vault classified in 5 levels assessed using an optical section during slit-lamp examination. Objective vault was measured with Visante OCT (Carl Zeiss Meditec Inc, Dublin, California, USA). RESULTS: Average values of objective and subjective vault were 414 +/- 228 mu m and 2.1 +/- 1.0, respectively and both parameters were highly correlated (r=0.82; P<.001). Differences in average objective vault were statistically significant among the 5 groups of subjective vault (P<.001). Subjective vault 0 corresponded to a mean OCT value of 62 49 mu m with 99% confidence interval (CI) [38; 86] mu m; eyes with vault 1 to 203 +/- 93 mu m with 99% CI [176; 230] mu m; eyes with vault 2 to 402 +/- 131 mu m with 99% CI [378; 425] mu m; eyes with vault 3 to 594 +/- 146 mu m, 99% CI [554; 633] mu m; and vault 4 to 794 +/- 182 mu m with 99% CI [713; 875] mu m. CONCLUSIONS: Subjective and objective values of vault are highly correlated. In 99% of cases within the CI, objective values for eyes subjectively classified within a certain level vary within a narrow interval (+/- 25 to 80 mu m) around the mean value, and this interval is characteristic of each subjective level. (Am J Ophthalmol 2009;147:978-983. (C) 2009 by Elsevier Inc. All rights reserved.)