Reassessment of the Clinical Significance of the Demarcation Line in the Corneal Stroma in Crosslinking

I. M. Kornilovskiy *

National Medical and Surgical Center Named after N. I. Pirogov, Ministry of Health of Russia, Moscow, Russia.

*Author to whom correspondence should be addressed.


Purpose: To consider the clinical significance and features of the formation of a demarcation line in the corneal stroma with various methods of corneal crosslinking.

Materials and Methods: Literature data on the evaluation of the effectiveness of various methods of crosslinking by the demarcation line in the corneal stroma were analyzed. The formation of a demarcation line during prophylactic and therapeutic excimer laser crosslinking was studied after various photorefractive operations, keratoconus and other pathologies of the cornea (168 operations).

Results: With various methods of crosslinking, including prophylactic and therapeutic excimer laser corneal crosslinking, the depth of the demarcation line in the stroma varied from 1/3 to 2/3 of the corneal thickness. It was noted that the saturation of the corneal stroma with a 0.25% solution of riboflavin is accompanied by a large increasing effect of the optical density in the stroma above the demarcation line at a shallower depth of its occurrence. The severity of the aseptic inflammatory reaction after corneal crosslinking affected the optical density, shape, intensity, and depth of the demarcation line in the stroma. In some cases, the formation of a demarcation line in the stroma was noted when the stroma was saturated with riboflavin immediately after refractive keratoablation without additional UV irradiation. The demarcation line in the stroma was revealed during inflammatory processes in the corneal stroma without the participation of riboflavin and its activation by UV radiation.  The study showed that the assessment of corneal crosslinking by the depth of the demarcation line is not an indicator of the photochemical process and the number of crosslinks formed in the corneal stroma.

Conclusion: Based on the severity, shape and depth of the demarcation line, it is not possible to judge the density of crosslinks in the corneal stroma, which predetermine its strength properties after one or another method of corneal crosslinking.

Keywords: Cornea, crosslinking, demarcation line, excimer laser, keratoconus, keratoectasias, riboflavin

How to Cite

Kornilovskiy, I. M. (2022). Reassessment of the Clinical Significance of the Demarcation Line in the Corneal Stroma in Crosslinking. Ophthalmology Research: An International Journal, 17(3), 33–41.


Download data is not yet available.


Seiler T., Hafezi F. Corneal Cross-Linking-Induced Stromal demarcation Line. Cornea 2006;25(9):1057–1059.

DOI:10.1097/01.ico.0000225720.38748.58 8.

Kymionis G.D., Grentzelos M.A., Plaka A.D., et al. Evaluation of the corneal collagen crosslinking using anterior optical coherence tomography. Cornea. 2013; 32:907–910.

DOI: 10.1097/ICO.0b013e31828733ea.

Koller T., Schumacher S., Fankhauser F II, et al. Riboflavin/ultraviolet a crosslinking of the paracentral cornea. Cornea. 2013;32:165–168.

DOI: 10.1097/ ICO.0b013e318269059b.

Kymionis .D., Tsoulnaras K.I., Grentzelos M.A., et al. Corneal stromal demarcation line after standard and high-intensity collagen crosslinking determined with anterior segment optical coherence tomography. J. Cataract Refract. Surg 2014; 40:736–740.

Kymionis, G.D.; Tsoulnaras, K.I.; Grentzelos, M.A.; Liakopoulos, D.A.; Tsakalis, N.G.; Blazaki, S.V.; Paraskevopoulos, T.A.; Tsilimbaris, M.K. Evaluation of corneal stromal demarcation line depth following standard and a modified-accelerated collagen cross-linking protocol. Am. J. Ophthalmol. 2014;158:671–675.e1.

Yam J.C., Cheng A.C. Reduced cross-linking demarcation line depth at the peripheral cornea after corneal collagen cross-linking. J Refract Surg. 2013; 29(1):49–53.

DOI: 10.3928/1081597X-20121228-03 4.

Moramarco A., Iovieno A., Sartori A., Fontana L. Corneal stromal demarcation line after accelerated crosslinking using continuous and pulsed light. J Cataract Refract Surg. 2015;41:2546–2551.

Malta J.B., Renesto A.C., Moscovici B.K., et al. Stromal demarcation line induced by corneal cross-linking in eyes with keratoconus and non-keratoconic asymmetric topography. Cornea 2015; 34:199–203.

DOI: 10.1097/ICO.00000000. 00000305.

Samantha Bonnel, MD; Marouen Berguiga, MD; Benoit De Rivoyre, JD; Gabriel Bedubourg, MD; Damien Sendon, MD; Françoise Froussart-Maille, MD, MSc; Jean-Claude Rigal-Sastourne, MD, MSc Demarcation Line Evaluation of Iontophoresis-AssistedAssisted Transepithelial Corneal Collagen Cross-linking for Keratoconus. J Refract Surg. 2015;31(1):36-40.

Ng A.L.K., Chan T.C.Y., Lai J.S.M. and Cheng A.C.K. Comparison of the central and peripheral cornel stromal demarcation line depth in conventional versus accelerated collagen cross-linking. Cornea 2015;34(11):1432–1436.

DOI: 10.1097/ ICO.0000000000000626.

Bikbova, G., Bikbov, M. Standard corneal collagen crosslinking versus transepithelial iontophoresis-assisted corneal crosslinking, 24 months follow-up: randomized control trial. Acta Ophthalmologica; 2016;94(7):е600-е606.

DOI: 10.1111/aos.13032

Spadea l., Tonti T., Vingolo EM. Corneal stromal demarcation line after collagen cross-linking in corneal ectatic diseases: a review of the literature. Clinical Ophthalmology, 2016;10:1803-1810.

Spadea, L.; Di Genova, L.; Tonti, E. Corneal stromal demarcation line after 4 protocols of corneal crosslinking in keratoconus determined with anterior segment optical coherence tomography. J. Cataract. Refract. Surg. 2018;44:596–602.

DOI: 10.1016/j.jcrs. 2018.02.017.PMID: 29685772.

Kornilovskiy I.M., Gilya A.P., Khatataev R.R. Excimer laser topographically oriented corneal crooslinking. Modern problems of science and education. 2021;2.

DOI 10.17513/spno.30613. URL: https://science

Kornilovskiy I.M. Photorefractive Keratectomy with Protection from Ablation-Induced Secondary Radiation and Cross-linking Effect. EC Ophthalmology. 2019; 10 (70): 563-570.

Kornilovskiy I.M. Prophylactic and Therapeutic Laser-Induced Corneal Crosslinking. EC Ophthalmology. 2020; 11(12):74-82.

Kornilovskiy I.M. Application of Pulsed Laser Radiation of the Far Ultraviolet Range for Corneal Crosslinking. Acta Scientific Ophthalmology.2021; 4(4):51-55.

Mazzotta, C.; Ferrise, M.; Gabriele, G.; Gennaro, P.; Meduri, A. Chemically Boosted Corneal Crosslinking for the Treatment of Keratoconus through a Riboflavin 0.25% optimized solution with High Superoxide Anion Release. J. Clin. Med. 2021;10:1324.

Available: 10.3390/jcm10061324.

Tomita M., Mita M., Huseynova T. Accelerated versus conventional corneal collagen crosslinking. J. Cataract Rafract. Surg. 2014;40:1013–1020.

DOI: 10.1016/j. jcrs.2013.12.012.

Pircher, N.; Lammer, J.; Holzer, S.; Gschließer, A.; Donner, R.; Pieh, S.; Schmidinger, G. Correlation between central stromaldemarcation line depth and changes in K values after corneal cross-linking (CXL). Graefes Arch. Clin. Exp. Ophthalmol. 2018;256:759–764.

D'Oria F, Puzo P, Incandela C, Sborgia A, Gigliola S, Boscia F, Alessio G.J Evaluation of Demarcation Line after Epithelium-Off Iontophoresis Corneal Collagen Cross-Linking for Progressive Keratoconus. Clin Med. 2021;10(15): 3295.

DOI: 10.3390/jcm10153295

PMID: 34362077 Free PMC article.

Yehia Salah, Kholoud Omar, Ahmed Sherif, Sarah Azzam Study of Demarcation Line Depth in Transepithelial versus Epithelium-Off Accelerated Cross-Linking (AXL) in Keratoconus. J Ophthalmol., 2019;2019:3904565.

DOI: 10.1155/2019/3904565. eCollection 2019.

Kymionis GD, Tsoulnaras KI, Liakopoulos DA, Skatharoudi CA, Grentzelos Corneal Stromal Demarcation Line Depth Following Standard and a Modified High Intensity Corneal Cross-linking Protocol. MA, Tsakalis NG.J Refract Surg. 2016; 32(4):218-22.

DOI: 10.3928/1081597X-20160216-01.PMID: 27070227.

Brosh K., Rozenman Y. Chemical Burn-Induced Stromal Demarcation Line. Cornea, 2016; 35(2): 286-288.

DOI: 10.1097/ICO.0000000000000667.

Doors M., Tahzib N.G., Eggink F.A., et al. Use of anterior segment optical coherence tomography to study corneal changes after collagen crosslinking. Am. J. Ophthalmol.,2009;148:844–851.e2.

DOI: 10.1016/j.ajo.2009.06.031.

Ng A.L.K., Chan T.C.Y., Lai J.S.M. and Cheng A.C.K. Comparison of the central and peripheral cornel stromal demarcation line depth in conventional versus accelerated collagen cross‑linking. Cornea 2015;34(11):1432–1436.

DOI: 10.1097/ICO.0000000000000626.