Intraoperative changes in corneal structure during excimer laser phototherapeutic keratectomy (PTK) assessed by intraoperative optical coherence tomography

  • Sebastian SiebelmannEmail author
  • Jens Horstmann
  • Paula Scholz
  • Björn Bachmann
  • Mario Matthaei
  • Manuel Hermann
  • Claus Cursiefen



Excimer laser phototherapeutic keratectomy (PTK) is a safe treatment for superficial corneal opacities, e.g., in corneal dystrophies or degenerations. Nevertheless, no standardized treatment protocols are available and intraoperative monitoring was not possible, so far. Here we evaluate the potential benefits of the intraoperative assessment by microscope-integrated intraoperative optical coherence tomography (MI-OCT) of corneal optical properties during PTK.


Retrospective study of eight patients (one male, seven females; age range, 43–80 years, mean = 66.1 years) using an 840-nm microscope-integrated spectral-domain OCT (iOCT; OptoMedical Technologies, Luebeck, Germany adapted to HS Hi-R Neo 900A, Haag Streit Surgical, Wedel, Germany). Images were acquired before and after corneal abrasion and after PTK. For PTK, a SCHWIND Amaris 750S excimer laser (SCHWIND eye-tech-solutions GmbH und KO. KG) was used. Parameters assessed were the central corneal thickness (CCT), changes in central depth-dependent corneal tissue intensity (TI), and corneal surface roughness (SR) in cross-sectional images of the cornea.


Intraoperative monitoring using microscope-integrated OCT was possible in all patients at all time points. TI of the anterior corneal stroma decreased significantly (p = 0.037) after PTK (T1 = 15.1 ± 3.6, T2 = 15.0 ± 3.84, T3 = 13.7 ± 3.38), but not after corneal abrasion alone, indicating increased transparency caused by excimer laser PTK. CCT was significantly lower after corneal abrasion (p = 0.017), but not after PTK (T1 = 630.4 ± 70 μm, T2 = 544.1 ± 59.4 μm, T3 = 558.3 ± 52.5 μm. SR significantly decreased (p = 0.043) after PTK (T1 = 614.4 ± 37.5 pixels, T2 = 634.4 ± 35.6 pixels, T3 = 611.0 ± 40.3 pixels).


Intraoperative OCT allows real-time imaging during PTK and the assessment of corneal optical transparency and its surface roughness. It has to be clarified in larger studies if these parameters correlate with later postoperative visual outcomes.


PTK Corneal dystrophy Excimer laser Surface treatment Intraoperative optical coherence tomography 



We thank Mrs. J. Austin for native language check.

Author contributions

Study concept, design: Siebelmann, Cursiefen.

Data collection/measurements: Siebelmann, Scholz, Hermann.

Analysis and interpretation of data: Siebelmann, Scholz, Matthaei, Bachmann, Horstmann, Cursiefen.

Drafting of the manuscript: Siebelmann, Scholz, Cursiefen.

Critical revision of the manuscript for intellectual content: Siebelmann, Scholz, Horstmann, Bachmann, Cursiefen.

Administrative, technical or material support: Siebelmann, Horstmann, Cursiefen.

Sebastian Siebelmann and Claus Cursiefen had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Funding/ support

DFG FOR 2240 “(Lymph)Angiogenesis and Cellular Immunity in Inflammatory Diseases of the Eye” (SS, JH, CC;; EU COST BM 1302 (BB, CC, SS; and EU ARREST BLINDNESS (CC, The sponsor or funding organization had no role in the design or conduct of this research. SS received a travel grant from Haag Streit Surgical.

The sponsors provided financial support in the form of personnel funding. All sponsors had no role in the design or conduct of this research.

Compliance with ethical standards

Conflict of interest

All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee (Ethics committee of the University Hospital of Cologne, File number 1 and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Financial disclosures



  1. 1.
    Campos M, Nielsen S, Szerenyi K, Garbus JJ, McDonnell PJ (1993) Clinical follow-up of phototherapeutic keratectomy for treatment of corneal opacities. Am J Ophthalmol 115:433–440CrossRefPubMedGoogle Scholar
  2. 2.
    Dinh R, Rapuano CJ, Cohen EJ, Laibson PR (1999) Recurrence of corneal dystrophy after excimer laser phototherapeutic keratectomy. Ophthalmology 106:1490–1497CrossRefPubMedGoogle Scholar
  3. 3.
    Fagerholm P, Fitzsimmons TD, Örndahl M, Öhman L, Tengroth B (1993) Phototherapeutic keratectomy: long-term results in 166 eyes. J Refract Surg 9:S76–S81Google Scholar
  4. 4.
    Mehlan J, Steinberg J, Traber L, Katz T, Linke S (2016) Recurrence rate and subjective symptoms after standardized (Hamburg protocol) phototherapeutic keratectomy on recurrent corneal erosions. Graefes Arch Clin Exp Ophthalmol 254(10):2005–2009CrossRefPubMedGoogle Scholar
  5. 5.
    Reddy JC, Rapuano CJ, Felipe AF, Nagra PK, Hammersmith KM (2014) Quality of vision after excimer laser phototherapeutic keratectomy with intraoperative mitomycin-C for Salzmann nodular degeneration. Eye Contact Lens 40:213–219CrossRefPubMedGoogle Scholar
  6. 6.
    Ma JJ, Tseng SS, Yarascavitch BA (2009) Anterior segment optical coherence tomography for transepithelial phototherapeutic keratectomy in central corneal stromal scarring. Cornea 28:927–929CrossRefPubMedGoogle Scholar
  7. 7.
    Mori H, Miura M, Iwasaki T, Goto H, Sakurai Y, Watanabe Y, Yasuno Y (2009) Three-dimensional optical coherence tomography-guided phototherapeutic keratectomy for granular corneal dystrophy. Cornea 28:944–947CrossRefPubMedGoogle Scholar
  8. 8.
    Wirbelauer C, Scholz C, Häberle H, Laqua H, Pham DT (2002) Corneal optical coherence tomography before and after phototherapeutic keratectomy for recurrent epithelial erosions. J Cataract Refract Surg 28:1629–1635CrossRefPubMedGoogle Scholar
  9. 9.
    Wirbelauer C, Scholz C, Hoerauf H, Engelhardt R, Birngruber R, Laqua H (2000) Corneal optical coherence tomography before and immediately after excimer laser photorefractive keratectomy. Am J Ophthalmol 130:693–699CrossRefPubMedGoogle Scholar
  10. 10.
    Siebelmann S, Steven P, Cursiefen C (2015) Intraoperative optical coherence tomography: ocular surgery on a higher level or just nice pictures? JAMA Ophthalmol 133:1133–1134CrossRefPubMedGoogle Scholar
  11. 11.
    Steven P, Le Blanc C, Lankenau E, Krug M, Oelckers S, Heindl LM, Gehlsen U, Huettmann G, Cursiefen C (2014) Optimising deep anterior lamellar keratoplasty (DALK) using intraoperative online optical coherence tomography (iOCT). Br J Ophthalmol.
  12. 12.
    Steven P, Le Blanc C, Velten K, Lankenau E, Krug M, Oelckers S, Heindl LM, Gehlsen U, Hüttmann G, Cursiefen C (2013) Optimizing Descemet membrane endothelial keratoplasty using intraoperative optical coherence tomography. JAMA Ophthalmol 131:1135–1142CrossRefPubMedGoogle Scholar
  13. 13.
    Siebelmann S, Steven P, Hos D, Lankenau E, Bachmann B, Cursiefen C (2016) Advantages of microscope-integrated intraoperative online optical coherence tomography: usage in Boston keratoprosthesis type I surgery. J Biomed Opt 21:016005–016005CrossRefGoogle Scholar
  14. 14.
    Siebelmann S, Cursiefen C, Lappas A, Dietlein T (2016) Intraoperative optical coherence tomography enables noncontact imaging during Canaloplasty. J Glaucoma.
  15. 15.
    Siebelmann S, Bachmann B, Lappas A, Dietlein TS, Steven P, Cursiefen C (2016) Intraoperative Optische Kohärenztomographie bei Narkoseuntersuchungen von Säuglingen und Kleinkindern. Ophthalmologe 113(8):651–655CrossRefPubMedGoogle Scholar
  16. 16.
    Siebelmann S, Hermann M, Dietlein T, Bachmann B, Steven P, Cursiefen C (2015) Intraoperative optical coherence tomography in children with anterior segment anomalies. Ophthalmology.
  17. 17.
    Ehlers JP, Kaiser PK, Srivastava SK (2014) Intraoperative optical coherence tomography using the RESCAN 700: preliminary results from the DISCOVER study. Br J Ophthalmol.
  18. 18.
    Ehlers JP, Dupps WJ, Kaiser PK, Goshe J, Singh RP, Petkovsek D, Srivastava SK (2014) The prospective Intraoperative and Perioperative ophthalmic ImagiNg with optical CoherEncE TomogRaphy (PIONEER) study: 2-year results. Am J Ophthalmol 158:999–1007 e1001 CrossRefPubMedPubMedCentralGoogle Scholar
  19. 19.
    McCafferty SJ, Schwiegerling JT, Enikov ET (2012) Corneal surface asphericity, roughness, and transverse contraction after uniform scanning excimer laser ablation. Invest Ophthalmol Vis Sci 53:1296–1305CrossRefPubMedGoogle Scholar
  20. 20.
    Kornmehl EW, Steinert RF, Puliafito CA (1991) A comparative study of masking fluids for excimer laser phototherapeutic keratectomy. Arch Ophthalmol 109:860–863CrossRefPubMedGoogle Scholar
  21. 21.
    Raiskup-Wolf F, Hoyer A, Spoerl E, Pillunat LE (2008) Collagen crosslinking with riboflavin and ultraviolet-a light in keratoconus: long-term results. J Cataract Refract Surg 34:796–801CrossRefPubMedGoogle Scholar
  22. 22.
    Schmidinger G, Pachala M (2012) Corneal pachymetry changes induced by different riboflavin solutions measured by optical coherence tomography. Invest Ophthalmol Vis Sci 53:4054–4054Google Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Sebastian Siebelmann
    • 1
    Email author
  • Jens Horstmann
    • 1
    • 2
  • Paula Scholz
    • 1
  • Björn Bachmann
    • 1
  • Mario Matthaei
    • 1
  • Manuel Hermann
    • 1
  • Claus Cursiefen
    • 1
  1. 1.Department of OphthalmologyUniversity of CologneCologneGermany
  2. 2.Cluster of Excellence: Cellular Stress Responses in Aging-Associated DiseasesUniversity of CologneCologneGermany

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