1.
Ocular Surface Disease Parameters After Collagen Cross-Linking for Keratoconus.
Recalde, JI, Acera, A, Rodríguez-Agirretxe, I, Sánchez-Tena, MA, San-Cristóbal, J, Durán, JA
Cornea. 2017;(2):148-152
Abstract
PURPOSE To analyze the variations in tear quantity and quality after corneal collagen cross-linking (CXL) in patients with keratoconus. METHODS This is a prospective observational study of 24 eyes with keratoconus that underwent epithelium-off CXL. The variables studied were tear film osmolarity, subjective symptoms (Ocular Surface Disease Index), tear breakup time, Schirmer test (SCH) score, tear clearance, fluorescein staining, and lissamine green staining. Variables were determined preoperatively and 3, 6, and 12 months after CXL. RESULTS All the studied variables remained stable after 1-year follow-up (no significant difference in comparison with baseline values; Mann-Whitney U test). There was a positive paired correlation between the SCH score and tear clearance at 3; 0.532 (P < 0.01), 6; 0.434 (P = 0.04), and 12 months; 0.675 (P < 0.01). There was no correlation between the SCH score and tear breakup time, apart from a positive correlation at 12 months; 0.601 (P = 0.05). A negative correlation was found between osmolarity and the SCH score at 3; -0.589 (P < 0.01) and 12 months; -0.049 (P = 0.04). The Ocular Surface Disease Index did not correlate with any of the studied variables (Spearman test). CONCLUSIONS CXL, at least during the first postoperative year, does not modify the parameters currently used to evaluate tear film function. There is no correlation between objective and subjective parameters in the analysis of the tear film function.
2.
Corneal Cross-Linking in Pediatric Patients With Progressive Keratoconus.
Wise, S, Diaz, C, Termote, K, Dubord, PJ, McCarthy, M, Yeung, SN
Cornea. 2016;(11):1441-1443
Abstract
PURPOSE To evaluate corneal cross-linking (CXL) in the treatment of keratoconus in pediatric patients. Specifically, this study investigates the impact of CXL on uncorrected distance visual acuity (UDVA), best-corrected distance visual acuity (BDVA), manifest refraction, keratometry (K) measurements, and higher order aberrations. METHODS This is a retrospective, observational case series of patients 18 years old or younger with progressive keratoconus who underwent CXL from January 2009 to August 2013. Preoperative and 1-year postoperative data including BDVA, manifest refraction, mean K readings, and corneal aberration measurements were extracted from clinical charts and topographical imaging. Visual acuity was converted to logarithm of the minimum angle of resolution (logMAR) scale, and mean refractive spherical equivalent (MRSE) was calculated from manifest refraction. RESULTS The group consisted of 39 eyes from 28 patients, including 21 males and 7 females (mean age = 16.3 years, range: 11-18, standard deviation [SD] = 1.81). UDVA did not change significantly (preoperative UDVA = 1.20 logMAR, SD = 0.57, and postoperative UDVA = 0.90 logMAR, SD = 0.67, P = 0.19). BDVA did not change significantly (preoperative BDVA = 0.34 logMAR, SD = 0.27, and postoperative BDVA = 0.34 logMAR, SD = 0.23, P = 0.50). There was no significant change in mean K (preoperative K = 48.49, SD = 5.44, and postoperative K = 48.25, SD = 4.74, P = 0.34). Mean MRSE did not change significantly (preoperative MRSE = -3.29 D, SD = 4.04, and postoperative MRSE = -3.53 D, SD = 4.07, P = 0.31). Corneal aberration measurements were available for 10 eyes, and stability of measurements was demonstrated. There were no complications noted. CONCLUSIONS This study suggests that CXL is a safe and effective procedure that halts the progression of keratoconus in pediatric patients at 1-year follow-up. To validate these findings, longer follow-up is required.
3.
Additive effect of repeated corneal collagen cross-linking in keratoconus.
Hafezi, F, Tabibian, D, Richoz, O
Journal of refractive surgery (Thorofare, N.J. : 1995). 2014;(10):716-8
Abstract
PURPOSE To report the long-term clinical outcome in a patient diagnosed as having bilateral progressive keratoconus who received a single corneal collagen cross-linking (CXL) treatment in the right eye and repeated CXL in the left eye. METHODS Observational case report. Topographical changes were assessed by high-resolution Scheimpflug imaging. The right eye underwent a standard epithelium-off CXL procedure in February 2008, followed by the left eye 4 weeks later. In 2012, the left eye was treated with CXL for a second time. Irradiation was performed in all cases at a fluence of 5.4 J/cm². Energy settings were 30 minutes @ 3 mW/cm² for the CXL procedures performed in 2008, and 10 minutes @ 9 mW/cm² for the second CXL procedure of the left eye that was performed in 2012. RESULTS The right eye that underwent a single CXL procedure showed a flattening of keratometry values between 2008 and 2012, followed by stabilization. The left eye showed a similar flattening effect between 2008 and 2012, followed by another flattening effect after the second CXL procedure and accompanied by a distinct increase in corrected distance visual acuity. CONCLUSIONS Following repeated CXL, the corneal stroma and endothelium remained inconspicuous, and postoperative haze and visibility of the stromal demarcation line was similar to what is usually observed after a single CXL procedure. Whether the additive flattening effect of the anterior surface observed in this single case goes along with an additive increase in biomechanical stiffness remains to be seen.