Faculty Bibliography

PURPOSE/OBJECTIVE:To compare 2 sequences of combined intrastromal corneal ring segment (ICRS) implantation and ultraviolet/riboflavin-mediated corneal collagen crosslinking (CXL) in progressive keratoconus. SETTING/METHODS:Dunya Eye Hospital, Istanbul, Turkey. METHODS:In this prospective comparative randomized consecutive study, CXL was followed by ICRS implantation (Group 1) or ICRS implantation was followed by CXL (Group 2). Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, spherical equivalent (SE), manifest cylinder (cylinder), and mean keratometry (K) were compared preoperatively and postoperatively. RESULTS:The mean interval between treatments was 7 months +/- 2 (SD) (mean follow-up, 13 +/- 1 months). The mean UDVA and CDVA improved in both groups (UDVA: 0.07 +/- 0.09 to 0.25 +/- 0.12, Group 1, and 0.11 +/- 0.09 to 0.32 +/- 0.21, Group 2; CDVA: 0.24 +/- 0.11 to 0.41 +/- 0.20 and 0.22 +/- 0.16 to 0.55 +/- 0.2, respectively). The mean SE, cylinder, and mean K values decreased in both groups (SE: -7.13 +/- 3.34 D to -2.98 +/- 2.33 D, Group 1, and -7.05 +/- 5.54 D to -2.81 +/- 4.08 D, Group 2; cylinder: -4.38 +/- 2.03 D to -2.62 +/- 1.93 D and -4.68 +/- 2.60 D to -2.20 +/- 1.67 D, respectively; mean K: 52.47 +/- 4.01 D to 48.31 +/- 3.65 D and 52.06 +/- 4.93 D to 48.08 +/- 4.13 D, respectively). Overall, there was more improvement in CDVA, SE, and mean K in Group 2 than in Group 1. CONCLUSION/CONCLUSIONS:Implantation of ICRS followed by CXL resulted in greater improvement of keratoconus.

BACKGROUND:Successful inflation of a tissue expander (TE) and coverage of the face with tissue of similar colour and texture is usually limited by the amount of skin generated during the reconstruction process. Overexpanding the TE device generates an increased flap size and an overall better reconstructive outcome. PATIENTS AND METHODS/METHODS:A total of 86 TEs were inserted into 48 burn patients with head and neck burn scars. In each case, a TE was inserted with subsequent overexpansion to 2-4 times the manufacturer's stated maximum volume. RESULTS:Using the above technique, we gained more transferable skin, which was then used to cover the defects. The rates of major and minor complications were the same as those obtained in previous studies. Illustrations of several representative cases are also included. CONCLUSIONS:Overinflation of smaller TEs minimises complication rates typically associated with this procedure. Cutaneous overexpansion can usually achieve the desired flap dimensions by overinflation of the implant well beyond the manufacturer's stated maximum volume, thus ensuring its success and allowing for better coverage of the defects.

PURPOSE/OBJECTIVE:To compare geometrical shape factors of keratoconus corneas after cross-linking (CXL) by means of Scheimpflug imaging with those of untreated fellow eyes. SETTING/METHODS:Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Switzerland. METHODS:Scheimpflug imaging of the anterior segments was performed with the Pentacam (Oculus, Wetzlar, Germany) in 21 patients with progressive keratectasia before and after CXL. Only 1 eye per patient was treated with corneal cross-linking using the riboflavin/UV-A approach, the fellow eye serving as control. The following corneal parameters and their postoperative evolution during 1 year after treatment have been evaluated: minimal curvature radius and its location, thickness at the thinnest point, location of the thinnest point, anterior and posterior elevation, conoid asphericity constants of the anterior and posterior surface, and 7 keratoconus indices. Statistical comparison was performed by means of the Wilcoxon test. RESULTS:None of the treated eyes showed topographic progression in contrast to the untreated group where 8 eyes experienced significant progression. Minimal curvature radius increased significantly after 1 year compared with preoperative (6.14-6.21 mm), whereas in the untreated fellow eye, it significantly decreased (6.94-6.86 mm). Minimal corneal thickness was significantly reduced after treatment (P < 0.002 at 12 months). The cornea showed an evolution toward a more regular shape as indicated by a significant reduction in 4 of 7 keratoconus indices. No complications of CXL occurred in this small study group. CONCLUSIONS:After cross-linking, the corneal shape undergoes a process of regularization. This process is active during the first year after treatment and may continue. Longer follow-up is warranted to estimate the full amount of regression of the keratectasia after CXL.

Corneal collagen crosslinking (CXL) with riboflavin and ultraviolet-A light is a method for treating progressive keratectasia. The currently accepted treatment parameters induce collagen crosslinking in the anterior 250 to 350 microm of corneal stroma. To protect the endothelium, CXL inclusion criteria require a minimum corneal thickness of 400 microm after removal of the epithelium. In advanced keratoconus, however, progressive corneal thinning often leads to a remaining stromal thickness of less than 400 microm. We have therefore modified the current treatment protocol by preoperatively swelling thin corneas to a stromal thickness of at least 400 microm using hypoosmolar riboflavin solution. This treatment protocol was performed in a case series of 20 patients, and no complications were observed. Preoperative swelling of the cornea safely broadens the spectrum of CXL indications to thin corneas that would otherwise not be eligible for treatment.

PURPOSE:To assess the progression of keratoconus in patients treated with collagen cross-linking with riboflavin and ultraviolet A (UVA) irradiation. METHODS:Thirty-eight eyes of 19 patients with progressive keratoconus were enrolled in a prospective comparative study. Average follow-up was 9 +/- 2 months (range: 5 to 12 months). The worse eye was treated with collagen cross-linking, and the fellow eye served as the control. Corneal epithelium was mechanically removed. Riboflavin 0.1% solution in dextran T-500 20% solution was applied every 2 to 3 minutes for 30 minutes throughout the irradiation. Ultraviolet A irradiation (370 nm) was performed using a commercially available UVA lamp for 30 minutes. RESULTS:The group treated with collagen crosslinking demonstrated a mean decrease (less myopic) in spherical equivalent refraction and cylinder of 1.03 +/- 2.22 diopters (D) (range: -5.25 to +3.75 D) and 1.04 +/- 1.44 D (range: -2.00 to +4.00 D), respectively (P < .01), and an increase in uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA) of 0.06 +/- 0.05 (range: 0.00 to 0.20) and 0.10 +/- 0.14 (range: -0.10 to 0.34), respectively (P < .01). The maximal curvature decreased by 1.57 +/- 1.14 D (range: 0.00 to 3.90 D), and intraocular pressure increased by 2 +/- 2 mmHg (range: -1 to 6 mmHg), which was statistically significant. No statistical difference was noted regarding central corneal thickness (P = .06) and endothelial cell count (P = .07). The untreated group showed no statistical difference for any of the clinical parameters, apart from UCVA and BSCVA, which decreased by 0.08 +/- 0.12 (range: -0.40 to 0.10) and 0.06 +/- 0.09 (range: -0.20 to 0.10), respectively (P < .01). CONCLUSIONS:Riboflavin/UVA collagen cross-linking appears to be efficacious in inhibiting the progression of keratoconus by reducing the corneal curvature, spherical equivalent refraction, and refractive cylinder in eyes with progressive keratoconus at average 9-month follow-up.

AIM/OBJECTIVE:To study the efficacy of silicone gel applied to hypertrophic burn scars, in reducing scar interference with normal function and improving cosmesis. METHODS:A randomised, double-blind, placebo-controlled trial involving 38 people with hypertrophic burn scars. Each scar was divided into two segments; silicone gel sheet was applied randomly to one of the two and placebo to the other. Participants were seen again after 1 and 4 months. Their data and wound characteristics were collected using the Vancouver scar scale. RESULTS:The median age of participants was 22 years (1.5-60 years) and 16 were male; 4 did not attend follow-up and were excluded from the study. There were no significant differences in baseline characteristics. Although after 1 month all scar scale measures were lower in treated areas, only the vascularity scale was significantly different between the two areas. After 4 months, all scale measures were significantly lower in the silicone gel group than in the control group, except for the pain score. CONCLUSION/CONCLUSIONS:Silicone gel is an effective treatment for hypertrophic burn scars.