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Post Info TOPIC: New Corneal Layer Found


Executive

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Date: Wed Jun 12 6:26 PM, 2013
New Corneal Layer Found
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They found a new layer in the cornea, in the article in the below link (and if I read it correctly), it is said to be where a Hydrops episode beginnings from, if it occurs. Does it "re-write the rules" ? not yet until others have studied it, I should think.

http://www.livescience.com/37348-new-layer-discovered-in-human-eye.html?cmpid=514645

Hopefully CXL will reduce the numbers of Hydrops occurring ?

Remo



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Date: Wed Jun 12 7:06 PM, 2013
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This is the part in the article on it below. There has to be one trigger or more than one triggers involved in activating the tear and causing the thinning and weakening to start with - which is still the holy grail in KC!

"Dua and colleagues, for example, believe that a tear in the Dua layer is what causes corneal hydrops, which occurs when water from inside the eye rushes in and leads to a fluid buildup in the cornea. This phenomenon is seen in patients with keratoconus, a degenerative eye disorder that causes the cornea to take on a cone shape."



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Date: Tue Jun 18 7:18 AM, 2013
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Here is the study abstract

Human Corneal Anatomy Redefined:

A Novel Pre-Descemet's Layer (Dua's Layer)

Presented at: the Societa Italiana Cellule Staminali e Superficie Oculare, VI CONGRESSO S.I.C.S.S.O. Lecce, June 14–16, 2007; The Royal College of Ophthalmologists, Annual Congress 2007, Symposium on Evolving Techniques in Corneal Surgery – Layer by Layer and EuCornea annual congress, Milan, 2012.

Received 21 August 2012; received in revised form 7 December 2012; accepted 10 January 2013. published online 28 May 2013. Corrected Proof

Manuscript no. 2012-1293.

Purpose

To define and characterize a novel pre-Descemet's layer in the human cornea.

Design

Clinical and experimental study.

Participants

We included 31 human donor sclerocorneal discs, including 6 controls (mean age, 77.7 years).

Methods

Air was injected into the stroma of donor whole globes (n = 4) and sclerocorneal discs (n = 21) as in the clinical deep anterior lamellar keratoplasty procedure with the big bubble (BB) technique. The following experiments were performed: (1) creation of BB followed by peeling of the Descemet's membrane (DM); (2) peeling off of the DM followed by creation of the BB, and (3) creation of the BB and continued inflation until the bubble popped to measure the popping pressure. Tissue obtained from these experiments was subjected to histologic examination.

Main Outcome Measures

Demonstration of a novel pre-Descemet's layer (Dua's layer) in the human cornea.

Results

Three types of BB were obtained. Type-1, is a well-circumscribed, central dome–shaped elevation up to 8.5 mm in diameter (n = 14). Type-2, is a thin-walled, large BB of maximum 10.5 mm diameter, which always started at the periphery, enlarging centrally to form a large BB (n = 5), and a mixed type (n = 3). With type-1 BB, unlike type-2 BB, it was possible to peel off DM completely without deflating the BB, indicating the presence of an additional layer of tissue. A type-1 BB could be created after first peeling off the DM (n = 5), confirming that DM was not essential to create a type-1 BB. The popping pressure was 1.45 bar and 0.6 bar for type-1 BB and type-2 BB, respectively. Histology confirmed that the cleavage occurred beyond the last row of keratocytes. This layer was acellular, measured 10.15±3.6 microns composed of 5 to 8 lamellae of predominantly type-1 collagen bundles arranged in transverse, longitudinal, and oblique directions.

Conclusions

There exists a novel, well-defined, acellular, strong layer in the pre-Descemet's cornea. This separates along the last row of keratocytes in most cases performed with the BB technique. Its recognition will have considerable impact on posterior corneal surgery and the understanding of corneal biomechanics and posterior corneal pathology such as acute hydrops, Descematocele and pre-Descemet's dystrophies.

Financial Disclosure(s)

The authors have no proprietary or commercial interest in any materials discussed in this article.

http://www.aaojournal.org/article/S0161-6420%2813%2900020-1/abstract

 



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