IER Matrix Study Update keeps contact lens practitioners better informed

The Institute for Eye Research (IER) has updated its comprehensive consumer and practitioner guide on the optimum combinations of silicone hydrogel contact lens and contact lens solutions, with the release of the IER Matrix Study Update. Published in the March 2008 edition of Contact Lens Spectrum, the study adds data resulting from recent investigations into combinations of the NIGHT & DAY™ (CIBA VISION) contact lens and solutions.

The original IER Matrix Study, published in September 2007 in Contact Lens Spectrum, presented data on solution-induced corneal staining (SICS) which occurred in long-term use of commercially available contact lens solutions and silicone hydrogel lenses. The study provides a guide to practitioners of the most bio-compatible contact lens and solution combinations for the eye. Each 3-month study involved 40 patients and examined a different combination of four different lenses and four available solutions.

Table 1 updates the results from the original IER Matrix Study, incorporating data from the NIGHT & DAY™ studies as well as changes to the ACUVUE® OASYS™ (Vistakon) with AQuify® (CIBA VISION) rate (2.5% to 2.6%), due to additional data.

Table 1. IER Matrix Study including NIGHT & DAY™ lenses (percentage of patients per month)

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In addition to the release of the latest data, the authors of the IER Matrix Study Update have challenged claims that the Andrasko Corneal Staining Grid (based on data retrieved from 2-hour exposures) is a good predictor of the IER Matrix Study findings (based on data resulting from 3-month exposures). They argue that a number of variables associated with long-term SICS, which are not incorporated in the Andrasko Grid, should not be overlooked when assessing SICS rates.

The following images include the Andrasko corneal staining data (Table 2), comparing the percentage area of staining versus percentage of patients with over 10% area of the cornea affected – patient percentages can be obtained by clicking on each cell in the Andrasko Staining Grid (www.staininggrid.com). Table 3 and Figure 1 provide comparisons between the IER Matrix Study data and the percentage patients with over 10% area affected in the Andrasko Staining Grid. To view full-sized versions click on the images.

Table 2. Andrasko Staining Grid percentage area versus percentage of patients affected (from www.staininggrid.com)	Table 3. IER Matrix versus Staining Grid for percentage of patients affected. Colours indicate 50% confidence interval analysis applied to each study with the lowest green, middle two quartiles yellow and highest orange	Figure 1. Correlation of Staining Grid and IER Matrix data excluding one outlier (PUREVISION™ with AQuify®). The orange line indicates where the data would lie if the Staining Grid 2-hour data accurately correlated with IER Matrix 3-month data
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