Vienna Cornea Study Group (VCSG)

The Vienna Cornea Study Group (VCSG) conducts clinical trials with an emphasis on novel diagnostic and treatment modalities in corneal diseases. The fields of research include early diagnosis and new therapeutic strategies of complex visual impairments such as degenerative or genetic corneal diseases (keratoconus, Fuchs‘ endothelial dystrophy, limbal stem cell deficiency, etc).

Currently we are recruiting for the following trials:

Comparison of anterior segment OCT devices (TOPOC-Study
Patients suspicious for keratoconus; age >18 years, no prior surgical interventions of the eye.

Ongoing Trials

Holosight Registry Study

Registry study for the clinical use of Holoclar transplants. Holoclar is a autologous stem-cell treatment used in the eye to replace damaged cells on the corneal surface (epithelium) of the cornea. It is used in adult patients with moderate to severe limbal stem-cell deficiency caused by burns, including chemical burns, to the eyes. Holoclar is a type of advanced therapy product called a ‘tissue engineered product’. It consists of cells taken from the patient’s limbus (at the edge of the cornea) and then grown in a laboratory so that they can be used to repair the damaged corneal surface.

TOPOC Study

With an incidence of 50-230 new cases per 100.000 people per year keratoconus represents the most frequent corneal ectatic disease. Corneal topography has been the gold standard for both, diagnosis of keratoconus as well as progression of the disease. Treatment decisions, such as corneal cross-linking, are mostly based on topographic findings. Therefore, precise and reliable measurements are of paramount importance. Several imaging devices based on different technologies, such as Scheimpflug and OCT, are currently coexisting, each capable of assessing corneal topography and pachymetry (thickness). However, there has been no data on comparability and interchangeable use of different devices in keratoconus patients. Aim of our study is to assess reproducibility and comparability of OCT-based and Scheimpflug based devices in terms of corneal topography and pachymetry in keratoconic eyes.

Evaluation of the Effect of Accelerated Corneal Cross-linking Protocols Using Two Different Riboflavin Solutions. A Prospective Trial.

Corneal cross-linking (CXL) has become the state-of-the-art therapy for the treatment of progressive keratoconus. CXL is a minimally invasive technique primarily used to stop corneal ectasia. The technique combines riboflavin and UV light to strengthen chemical bonds in the cornea, thereby stiffening a structurally weak and unstable cornea. In order to improve the treatment for both, the patients and health care providers, multiple new accelerated treatment protocols are currently being introduced. Different mechanisms are available, such as higher UV irradiation energies, different applications of riboflavin instilment or faster penetrating riboflavin solutions. Aim of our study is to compare two differently penetrating riboflavin solutions and assess treatment success and complication rates.

Corneal Epithelium and Bowman's Layer Thickness Maps in Keratoconic and Healthy Eyes imaged by Polarization-Sensitive (PS-)OCT. 

Polarization-sensitive OCT (PS-OCT) is an extension to conventional OCT that allows the differentiation of tissues based on their polarization changing properties. Using PS-OCT even the fines structures of the cornea, such as the epithelium or the Bowman’s layer, can specifically be imaged and segmented. This is of special interest since Bowman’s layer has only been assessable by microscopy in embedded tissue sections. Aim of the project is to assess differences between epithelium thickness and Bowman's layer thickness maps in keratoconic and healthy eyes of study participants. Advanced, tissue-specific imaging by PS-OCT may reveal new diagnostic biomarkers and prove its diagnostic importance for the early detection of keratoconus patients.

Ex vivo Corneal Cross-linking of Human Corneal Transplants

Keratoplasty (corneal transplantation) is a well-established and safe procedure for several indications, such as corneal degenerations, dystrophies, trauma, scarring, and advanced keratoconus, and yields good visual and optical outcomes. However, corneal melting after transplantation is a very severe complication and most commonly results in the need of a re-keratoplasty accompanied with an increased risk of future complications. CXL involves a photopolymerization process that increases biomechanical and biochemical stability, leading to increased corneal rigidity and resistance to enzymatic digestion. Therefore, preoperative CXL of corneal transplants may reduce postoperative corneal melting of the graft. The purpose of this project is to establish new methods of pre-OP CXL and to assess efficacy and safety of ex vivo CXL in human corneal transplants stored in culture media. Patients requiring keratoplasty due to corneal melting might benefit from the strengthening effect of pre-operative CXL of donor tissue.

Recent Publications

Endothelial Safety and Efficacy of Ex Vivo Collagen Cross-linking of Human Corneal Transplants.
Lammer J, Laggner M, Pircher N, Fischinger I, Hofmann C, Schmidinger G.
Am J Ophthalmol. 2020 Jun;214:127-133. doi: 10.1016/j.ajo.2020.02.024. Epub 2020 Mar 12.
PMID: 32171767

Large Field of View Corneal Epithelium and Bowman's Layer Thickness Maps in Keratoconic and Healthy Eyes.
Pircher N, Beer F, Holzer S, Gschließer A, Donner R, Pircher M, Hitzenberger CK, Schmidinger G, Lammer J.
Am J Ophthalmol. 2020 Jan;209:168-177. doi: 10.1016/j.ajo.2019.05.025. Epub 2019 Jun 3.
PMID: 31170392

Corneal crosslinking for pellucid marginal degeneration.
Pircher N, Lammer J, Holzer S, Gschließer A, Schmidinger G.
J Cataract Refract Surg. 2019 Aug;45(8):1163-1167. doi: 10.1016/j.jcrs.2019.03.018. Epub 2019 Jul 2.
PMID: 31272773

Ultrahigh-resolution anterior segment optical coherence tomography for analysis of corneal microarchitecture during wound healing.
Pantalon A, Pfister M, Aranha Dos Santos V, Sapeta S, Unterhuber A, Pircher N, Schmidinger G, Garhöfer G, Schmidl D, Schmetterer L, Werkmeister RM.
Acta Ophthalmol. 2019 Aug;97(5):e761-e771. doi: 10.1111/aos.14053. Epub 2019 Feb 14.
PMID: 30762310

Mapping of Corneal Layer Thicknesses With Polarization-Sensitive Optical Coherence Tomography Using a Conical Scan Pattern.
Beer F, Wartak A, Pircher N, Holzer S, Lammer J, Schmidinger G, Baumann B, Pircher M, Hitzenberger CK.
Invest Ophthalmol Vis Sci. 2018 Nov 1;59(13):5579-5588. doi: 10.1167/iovs.18-25311.
PMID: 30481276

Distinguishing Keratoconic Eyes and Healthy Eyes Using Ultrahigh-Resolution Optical Coherence Tomography-Based Corneal Epithelium Thickness Mapping.
Pircher N, Schwarzhans F, Holzer S, Lammer J, Schmidl D, Bata AM, Werkmeister RM, Seidel G, Garhöfer G, Gschließer A, Schmetterer L, Schmidinger G.
Am J Ophthalmol. 2018 May;189:47-54. doi: 10.1016/j.ajo.2018.02.006. Epub 2018 Feb 16.
PMID: 29458037

Correlation between central stromal demarcation line depth and changes in K values after corneal cross-linking (CXL).
Pircher N, Lammer J, Holzer S, Gschließer A, Donner R, Pieh S, Schmidinger G.
Graefes Arch Clin Exp Ophthalmol. 2018 Apr;256(4):759-764. doi: 10.1007/s00417-018-3922-z. Epub 2018 Feb 23.
PMID: 29476249 Free PMC article. Clinical Trial.

Ultrahigh-resolution OCT imaging of the human cornea.
Werkmeister RM, Sapeta S, Schmidl D, Garhöfer G, Schmidinger G, Aranha Dos Santos V, Aschinger GC, Baumgartner I, Pircher N, Schwarzhans F, Pantalon A, Dua H, Schmetterer L.
Biomed Opt Express. 2017 Jan 30;8(2):1221-1239. doi: 10.1364/BOE.8.001221. eCollection 2017 Feb 1.
PMID: 28271013

Effect of a Matrix Therapy Agent on Corneal Epithelial Healing After Standard Collagen Cross-linking in Patients With Keratoconus: A Randomized Clinical Trial.
Bata AM, Witkowska KJ, Wozniak PA, Fondi K, Schmidinger G, Pircher N, Szegedi S, Aranha Dos Santos V, Pantalon A, Werkmeister RM, Garhofer G, Schmetterer L, Schmidl D.
JAMA Ophthalmol. 2016 Oct 1;134(10):1169-1176. doi: 10.1001/jamaophthalmol.2016.3019.
PMID: 27584715 Clinical Trial.

Changes in straylight and densitometry values after corneal collagen crosslinking.
Pircher N, Pachala M, Prager F, Pieh S, Schmidinger G.
J Cataract Refract Surg. 2015 May;41(5):1038-43. doi: 10.1016/j.jcrs.2014.07.043. Epub 2015 May 5.
PMID: 25953473