1 / 11

Oliver Findl 1,2 , Nino Hirnschall 1,2 , Alja Crnej 2 1 VIROS Vienna Institute for Research in Ocular Surgery, Hanu

Effect of Fluorescein dye staining of the tear film on Scheimpflug measurements of central corneal thickness. Oliver Findl 1,2 , Nino Hirnschall 1,2 , Alja Crnej 2 1 VIROS Vienna Institute for Research in Ocular Surgery, Hanusch Hospital, Vienna, Austria

nikki
Download Presentation

Oliver Findl 1,2 , Nino Hirnschall 1,2 , Alja Crnej 2 1 VIROS Vienna Institute for Research in Ocular Surgery, Hanu

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Effect of Fluorescein dye staining of the tear film on Scheimpflug measurements of central corneal thickness Oliver Findl 1,2, Nino Hirnschall 1,2, Alja Crnej 2 1 VIROS Vienna Institute for Research in Ocular Surgery, Hanusch Hospital, Vienna, Austria 2 Moorfields Eye Hospital, London, UK Financial interest: none OF is scientific advisor to Alcon, AMO, Croma & Carl Zeiss Meditec AG

  2. Background • Fluorescein dye is commonly used in routine ophthalmic examination • staining epithelial defects of the cornea • break up time of the tear film • Goldmann applanation tonometry • Correct CCT measurement needed for: • corneal refractive surgery • diagnosis of corneal diseases (keratoconus) • to correct for systematic errors of IOP measurements using Goldmann applanation.

  3. CCT measurement devices • Pentacam: rotating Scheimpflug photographic • measures the thickness from the image, which is created from the back-scattered light from the corneal tissue => Influenced by fluorescein eye drops? • ACMaster: partial coherence interferometry (PCI) • gold standard for CCT measurement • measures distances between surface interfaces with a different refractive index

  4. Methods • Prospective randomised controlled study • 30 eyes of 15 patients (8 female, 7 male)

  5. Methods 3 x rotating Scheimpflug imaging + 3 x PCI measurement Instilling 0.25% fluorescein + 0.5% proxymetacaine hydrochloride Rotating Scheimpflug imaging + PCI measurement Irrigation with 2ml BSS Rotating Scheimpflug imaging + PCI after 5min, 10min, 20min, 40min, 60min, (120min) Rotating Scheimpflug imaging + PCI

  6. With Fluorescein Without Fluorescein

  7. Results Rotating Scheimpflug: 46.6µm difference PCI: 1.6µm difference

  8. Results CCT difference (PCI) in µm CCT difference (Scheimpflug) in µm

  9. Results Number of patients (%) with a fluorescein layer +5µm compared to baseline Subjects with Fluorescein layer (%) time after applying Fluorescein (min) Fluorescein layer -> more than 5µm difference to the baseline measurement

  10. Results Schirmer 2 results (sec) time after applying Fluorescein (min)

  11. Conclusion • Scheimpflug imaging • Fluorescein dye causes intense back-scatter of light resulting in a measurement error • Irrigating the eye reduces this effect only insignificantly • PCI: is not influenced by altered or higher reflectivity • => Fluorescein eye drops MUST NOT be used prior to Scheimpflug imaging measurements

More Related