<h4>PURPOSE</h4> <p> To evaluate the safety and efficacy of staged ultraviolet A (UVA) cross-linking following intrastromal 0.1% riboflavin administration in eyes with advanced corneal edema.</p> <h4>METHODS</h4> <p>Ten eye bank corneas divided in two groups (n=5) were placed on a pressurized artificial anterior chamber following Descemet&rsquo;s membrane stripping. Two consecutive corneal pockets (350- and 150-&micro;m depth) were sequentially created using a femtosecond laser. Sequential intrastromal injections of 0.1% riboflavin (0.2 mL) followed by either UVA irradiation (15 mW/cm²) for 7 minutes or exposure to air were performed for each pocket. Corneal clarity and central thickness were measured before and after the two UVA cross-linking steps. The same steps were clinically applied in an 84-year-old woman with bullous keratopathy prior to corneal transplantation and followed for 6 months. </p> <h4>RESULTS</h4> <p>The corneal clarity improved in the treated but not the control eyes. The mean central corneal thickness was significantly reduced by 256 &micro;m (ultrasound, <em>P</em>=.0002) and 273 &micro;m (Scheimpflug, <em>P</em>=.0004) in treated eyes, but only 100 &micro;m (ultrasound, <em>P</em>=.048) and 107 &micro;m (Scheimpflug, <em>P</em>=.075) in the control eyes. The clinical treatment of corneal edema showed improved clarity and reduced central corneal thickness from 675 to 550 &micro;m (ultrasound) and 696 to 571 &micro;m (Scheimpflug) at 1 month. Best spectacle-corrected visual acuity improved from finger counting to 20/80 at 1 week and beyond, postponing corneal transplantation for &gt;6 months.</p> <h4>CONCLUSIONS</h4> <p>Staged UVA cross-linking (15 mW/cm²) with femtosecond laser facilitated intrastromal 0.1% riboflavin administration may be a safe (no corneal scarring) and effective (marked reduction of edema) temporizing alternative method for managing bullous keratopathy. [<cite>J Refract Surg.</cite> 2008;24:S730-S736.]</p> <h4>ABOUT THE AUTHORS</h4> <p>From Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio (Krueger, Ramos-Esteban); NYU Medical School, New York, NY (Kanellopoulos); and Laservision.gr Institute, Athens, Greece (Kanellopoulos).</p> <p>This study was supported by a Cleveland Clinic Institutional Grant from Research to Prevent Blindness Inc, New York, NY, and with cornea tissue from the Eye Bank for Sight Restoration, New York, NY.</p> <p>The authors have no financial interest in the materials presented herein.</p> <p>Presented in part at the International Congress of Corneal Cross-Linking; December 7-8, 2007, Zurich, Switzerland; American Society of Cataract and Refractive Surgeons annual meeting, April 1-4, 2008, Chicago, Ill; and World Ophthalmic Congress, June 28 - July 1, 2008, Hong Kong.</p> <p>Correspondence: A. John Kanellopoulos, MD, Laservision.gr Institute, 15-17 Tsocha St, Athens, Greece 11521. Tel: 30 210 7472777; Fax: 30 210 7472789; E-mail: <a href="mailto:laservison@internet.gr">laservison@internet.gr</a></p> <p> <p><em>Click <a href="~/link.aspx?_id=E6F874AC61DB4745A50F1E6EA0851316&amp;_z=z">here</a> to re</em><em>ad the Letter to the Editor.</em><span style="text-decoration: underline;"><br /> </span></p> <a href="mailto:laservison@internet.gr"><br /> </a></p>

PURPOSE: To determine how changes in corneal elasticity/stiffness might influence intraocular pressure (IOP) readings in diabetic patients. METHODS: A systematic review of the literature was performed to understand the conflicting relationship between diabetes, elevated IOP, and glaucoma progression. RESULTS: Diabetic patients have been found to have statistically significant higher IOP readings in some population-based studies compared to non-diabetics. Insulin resistance states, hyperglycemia and glycosylated hemoglobin have been correlated with higher IOP (1 mmHg) measurements in diabetic patients. In the Ocular Hypertension Treatment Study (OHTS), a self reported history of diabetes was found to be protective against the progression of primary open-angle glaucoma. Small differences in IOP measurements in diabetic patients may be due to corneal stiffening, as demonstrated by the protective effect of glucose-mediated collagen cross-linking against the manifestation and keratometric progression of keratoconus. Different collagen cross-linking agents may induce different degrees of corneal stiffening, which can result in differences in measured IOP. CONCLUSIONS: Glucose-mediated corneal stiffening due to collagen cross-linking might be responsible for IOP overestimation in diabetic patients. Corneal stiffening might explain why diabetic eyes tend to have higher IOP readings in large population-based studies and why those with ocular hypertension have a reduced risk for glaucoma progression. [J Refract Surg. 2007;23:85-88.]

Rainbow glare is a mild optical side effect of femtosecond LASIK. In this study, higher raster energy levels and length of time between service calls were associated with the occurrence of rainbow glare.