Use of anterior segment optical coherence tomography to study corneal changes after collagen cross-linking.
OBJECTIVE
To investigate the stromal demarcation line after corneal cross-linking using anterior segment optical coherence tomography (AS-OCT) and its influence on the short-term results of cross-linking in patients with progressive keratoconus.


METHODS
Prospective, nonrandomized study.


METHODS
Twenty-nine eyes of 29 patients with progressive keratoconus (n = 28) or after laser in situ keratomileusis ectasia (n = 1) were included and treated with corneal cross-linking at our institution. Measurements at 1, 3, 6, and 12 months after corneal cross-linking were: refraction, best-corrected visual acuity (BCVA), tonometry, corneal topography, AS-OCT, specular microscopy, and aberrometry. Demarcation line depth was measured centrally, 2 mm temporally, and 2 mm nasally by two independent observers using AS-OCT and was correlated with clinical parameters.


RESULTS
The stromal demarcation line was visible with AS-OCT at 1 month after surgery in 28 of 29 eyes. Pairwise comparisons between the two observers of the AS-OCT measurements did not show a statistically significant difference. After an initial steepening of maximal keratometry values and a decrease in BCVA at 1 month after surgery (both with P < .012), no significant changes were found at 3, 6, and 12 months after surgery compared with before surgery. Refractive cylinder, topographic astigmatism, aberration values, endothelial cell density, and intraocular pressure remained stable during all postoperative visits. A deeper demarcation line depth was associated with a larger decrease in corneal thickness (r = -0.506; P = .012).


CONCLUSIONS
AS-OCT is a useful device to detect the stromal demarcation line after corneal cross-linking. At 3 to 12 months follow-up, all clinical parameters remained stable, indicating stabilization of the keratoconic disease.
Department of Ophthalmology, University Medical Center Maastricht, Maastricht, The Netherlands.
Muriël
M
Doors
Nayyirih G
NG
Tahzib
Fred A
FA
Eggink
Tos T J M
TT
Berendschot
Carroll A B
CA
Webers
Rudy M M A
RM
Nuijts
D057128:Aberrometry; D000328:Adult; D000368:Aged; D000869:Anterior Eye Segment; D002452:Cell Count; D003094:Collagen / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism* / Q000473:pathology*; D019781:Corneal Topography; D004108:Dilatation, Pathologic / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism; D004728:Endothelium, Corneal / Q000473:pathology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D007431:Intraoperative Complications; D007640:Keratoconus / Q000188:drug therapy / Q000378:metabolism; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects; D008875:Middle Aged; D010778:Photochemotherapy; D011183:Postoperative Complications; D011446:Prospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D041623:Tomography, Optical Coherence; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
D003094:Collagen; D012256:Riboflavin