Very few studies have described the molecular genetic features of ADH Table 1 and these are further limited because most were carried out on small numbers of samples using low resolution methodology, such as microsatellite marker based loss of heterozygosity LOH or allelic imbalance AI analysis and cytogenetic comparative genomic hybridization CGH zithromax side effects 5 All patients should have a baseline retinal exam within the first year of administration to evaluate for other pre existing ocular conditions or tissue damage that might interfere with the interpretation of screening tests