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Naveen Mysore, Jeff Goshe; Descemet’s “Wrinkles”: A potential clinical indicator to verify adequate tunnel depth prior to pneumatic dissection in DALK surgery. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):1593.
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To validate “wrinkles” in Descemet’s membrane as a clinical sign for identifying the correct tunnel depth for the big bubble technique in deep anterior lamellar keratoplasty (DALK). Anwar and Teichmann’s big bubble technique for DALK was a major improvement in lamellar keratoplasty. Success of the pneumatic dissection is dependent on the correct depth to inject the air bubble. It has been previously suggested that wrinkles in Descemet’s membrane can be seen if the dissector is at the correct depth (Goshe et al., JCRS 2011; 37:1923 - 1927). In this paper, we will show that this is a reliable and reproducible clinical sign, which can be used as an alternative to intraoperative OCT.
Six cadaveric eyes from three donors without known corneal pathology were acquired from the Illinois Eye Bank. Each eye was mounted on a Mastel platform (San Diego, CA) and pressurized to physiologic IOP (by digital palpation). A small amount of glycerin was applied to the surface. Vacuum trephination was carried out to a depth of approximately 350 um. The trephinated edge was stabilized and a Fogla dissector was advanced centrally and posteriorly into the cornea until “wrinkles” in Descemet’s membrane (defined for our purposes as two or more parallel lines oriented tangential to the advancing tip of the dissector) were clearly identifiable. The dissector was removed and anterior segment OCT (Bioptigen, Durham, NC) was performed to quantitatively assess the depth of the dissector. The measurements were performed with the calipers on the measurement software.
The central corneal thickness varied from 670 - 1103 um. Wrinkles in Descemet’s membrane were seen when the thickness of the stroma below the Fogla dissector was 67 - 170 um. The average was 125.8 ± 38.1 um. Increased number and prominence of wrinkles was seen at a lower stromal thickness. These values correlate well with previous work using intraoperative OCT by Scorcia et al. (Ophthalmology 2013; 120:47-476), where a 70 % big bubble success rate was achieved at an average thickness of 90.4 ± 27.7 um.
Wrinkles in Descemet’s may be a reliable and reproducible clinical sign that can be used as an alternative to intraoperative OCT to determine if adequate tunnel depth is achieved before attempting pneumatic dissection during DALK surgery.
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