Microstructural assessment of rare corneal dystrophies using real-time in vivo confocal microscopy

Purpose: To analyse and describe three cases of rare corneal dystrophy and highlight their in vivo microstructural features. Methods: Subject 1 was diagnosed with a posterior stromal fleck corneal dys trophy. Two of her three children were also affected. Subjects 2 and 3 exhi bited an almost identical clinical appearance on biomicroscopic examination , such that both clinically were diagnosed as having pre-Descemet's dystrop hies. All subjects underwent in vivo confocal microscopy and approximately 300 sequential digital images were obtained and analysed for each cornea. Results: In vivo confocal microscopy of subject 1 demonstrated an abnormal appearance of numerous large ovoid particles, measuring 50-70 mum in diamet er in the mid and posterior stroma as well as smaller hyperreflective dot-l ike intracellular deposits, of less than 1 mum diameter. Despite the near-i dentical clinical appearance, subjects 2 and 3 could be clearly differentia ted by in vivo confocal microscopy. Subject 2 exhibited small, irregular, o ptically dense particles, mainly in the anterior stroma, whereas subject 3 possessed classical involvement of the stroma immediately adjacent to Desce met's membrane, with numerous regular, small, hyperreflective particles. Conclusions: The ability of in vivo confocal microscopy to localize and acc urately measure various elements in different corneal layers may help to re solve whether abnormalities are intra- or extracellular, and aid clearer di fferentiation of rare corneal disorders.