Keratoconus is the most common ectatic disorder of the cornea and is a cause of significant visual loss in children. The disease is bilateral, but frequently asymmetric. Keratoconus has historically been thought to be noninflammatory in etiology, although its exact mechanism is unproven at present. Keratoconus is characterized by changes in corneal collagen structure and organization that cause biomechanical instability with subsequent development of irregular astigmatism, progressive myopia, corneal thinning and central corneal scarring, all of which result in mild to marked impairment in visual acuity.

Purpose: To present the results of the injection of an intravitreal implant of dexamethasone 0.7 mg (DEX 0.7 mg) in 4 patients with an immunologic graft rejection after penetrating keratoplasty.Methods: Two of the patients received DEX 0.7 mg because inflammation and corneal edema not related to endothelial cell loss persisted despite the administration of topical prednisolone acetate, subconjunctival betamethasone, and systemic methylprednisolone. The other 2 cases received DEX 0.7 mg at the time rejection was diagnosed.Results: At 1 and 6 months after implantation, all rejection episodes resolved with improvement in uncorrected and bestcorrected visual acuity, restoration of graft transparency, reduction of central corneal thickness, and no significant increase in intraocular pressure.Conclusions: In 4 eyes with an immunologic graft rejection after penetrating keratoplasty, the dexamethasone 0.7 mg intravitreal implant was an effective treatment option, even in cases refractory to standard topical and systemic therapy.

Purpose of reviewDescemet stripping automated endothelial keratoplasty (DSAEK) has become worldwide the procedure of choice for the replacement of diseased corneal endothelium. More recently, ultrathin DSAEK (UT-DSAEK) has been introduced to guarantee better visual outcomes preserving good donor graft manipulation.Recent findingsAs DSAEK may still have major challenges such as suboptimal visual acuity and relatively slow visual rehabilitation, fairly new techniques such as UT-DSAEK and Descemet membrane endothelial keratoplasty (DMEK) have been introduced to allow much quicker and optimal visual rehabilitation. This article goes through the most recent findings and results of these techniques.SummaryUT-DSAEK is a procedure that shares the improved visual outcome and lower immunologic rejection rate of DMEK over DSAEK, while minimizing all types of postoperative complications. In addition, similar to DSAEK and unlike DMEK, UT-DSAEK can be performed in all types of eyes, even in those with complicated anatomy or poor anterior chamber visualization.

Descemet stripping automated endothelial keratoplasty (DSAEK) has become worldwide the procedure of choice for the replacement of diseased corneal endothelium. More recently, ultrathin DSAEK (UT-DSAEK) has been introduced to guarantee better visual outcomes preserving good donor graft manipulation.As DSAEK may still have major challenges such as suboptimal visual acuity and relatively slow visual rehabilitation, fairly new techniques such as UT-DSAEK and Descemet membrane endothelial keratoplasty (DMEK) have been introduced to allow much quicker and optimal visual rehabilitation. This article goes through the most recent findings and results of these techniques.UT-DSAEK is a procedure that shares the improved visual outcome and lower immunologic rejection rate of DMEK over DSAEK, while minimizing all types of postoperative complications. In addition, similar to DSAEK and unlike DMEK, UT-DSAEK can be performed in all types of eyes, even in those with complicated anatomy or poor anterior chamber visualization.

PURPOSE:To evaluate a new curvature gradient topography map to predict postoperative corneal remodeling.METHODS:In this retrospective study, 32 eyes of 16 patients with myopia underwent excimer ablation surgery with a postoperative high curvature gradient. The new curvature gradient map (acquired immediately postoperatively) shows the difference between the curvatures of two points over the distance between them; it was compared to the tangential curvature difference map between 1 and 12 months postoperatively to determine their relationship. Corneas were divided into 12 regions for analysis: four 90°-wide sectors centered on 0°, 90°, 180°, and 270°. There were three subdivisions in each sector: central (radius: 0 to 2.75 mm), paracentral (radius: 2.75 to 3.25 mm), and peripheral (radius: 3.25 to 4.5 mm). Linear regression analysis was performed by region.RESULTS:The following regions had significant relationships between the initial curvature gradient and curvature difference between 1 and 12 months postoperatively: the paracentral zone of the 90° sector (P = .0145; R(2) = 0.1832) and both the central (P = .0034; R(2) = 0.2522) and paracentral (P = .0452; R(2) = 0.1271) zones of the 270° sector. The greatest average initial tangential curvature was in the 270° sector.CONCLUSIONS:The initial curvature gradient after surgery predicted change in tangential curvature over the subsequent 12 months in areas where initial tangential curvature was greatest. When the curvature gradient was high, the surface curvature modification remained in progress months after surgery.

To the Editor: The same stromal opacities found in the rabbit study by Salomão et al, 1 which appeared in the June 2011 issue of the Journal of Refractive Surgery, have been previously described as frequent but asymptom-atic complications after corneal cross-linking (CXL) in cases of steep corneas with keratometry values Ͼ54.00 diopters (D). 2-4 Raiskup et al 4 demonstrated that infusion with a hypo-osmolar ribofl avin solution preserved cor-neal tissue from stromal opacity development even in severe keratoconus cases with ultra-thin corneas, with no reduction of CXL effectiveness. The same phenomenon was observed by our group 5 in patients with postopera-tive LASIK ectasia. Corneas were plumped with hypo-tonic ribofl avin before CXL irradiation. 6 None of the patients developed any stromal opacity, despite their mean central corneal thickness (CCT) was less than the recognized safe cutoff depth of 400 μm. We found that the usual development of deep stromal opacities after CXL was related to a reduction of CCT at 1 month after CXL. Therefore, we decided to study CCT behavior during CXL in 45 corneas with keratoconus. Mean patient age was 27 years (range: 19 to 37 years). After 20 minutes of soaking with 0.1% ribofl avin solution (10 mg ribofl avin-5-phosphate in 20% dextran-T-500 10 mL), all corneas with CCT Ͻ350 μm were plumped to 400 μm with a hypo-osmolar solution (ribofl avin-5-phosphate) for a mean time of 8 minutes. Intraoperative CCT was measured with ultrasound pachymetry after epithelial removal (t1), after 20 minutes of ribofl avin infusion (t2), after corneal expansion (t3), and at the end of irradiation (t4) (Fig). Posterior stromal opacity formation was evaluated by anterior segment optical coherence tomography up to 12 months postoperatively. No signifi cant difference (P=.003) was found after epi-thelium removal. A mean CCT reduction of 102.11 μm was measured after 20 minutes of ribofl avin infusion (PϽ.00001). No signifi cant change in CCT was measured at the end of corneal expansion (P=.51) or irradiation (P=.016). Eyes were also divided into 3 groups of 15 eyes each according to preoperative CCT (group I Ͻ450 μm, group II between 450 and 500 μm, and group III Ͼ500 μm). The decrease in CCT after the fi rst 20 minutes of ribofl avin infusion was signifi cantly higher in group III, with a 28% CCT reduction. Groups I and II showed a 22% and 25% decrease in CCT, respectively. None of the patients …

PURPOSE: To report refractive, topographic, aberrometric, and tomographic outcomes 24 months after corneal cross-linking (CXL) in patients up to 18 years of age with progressive keratoconus.DESIGN: Prospective, interventional case series.METHODS: Forty eyes underwent riboflavin-ultraviolet A-induced CXL. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), sphere and cylinder, topography, aberrometry, tomography, and endothelial cell counts were evaluated at baseline and at 1, 3, 6, 12, and 24 months.RESULTS: Mean logarithm of the minimum angle of resolution baseline UCVA and BSCVA were 0.79 +/- 0.21 and 0.39 +/- 0.10, respectively. Mean UCVA and BSCVA at 2 years were 0.58 +/- 0.18 and 0.20 +/- 0.09, respectively. The improvement in UCVA and BSCVA was significant throughout the postoperative follow-up (P < .05). Mean spherical equivalent refraction showed a significant decrease of 1.57 diopters (D) at 24 months (P = .02). Mean baseline simulated keratometry was 46.32 D in the flattest meridian and 51.48 D in the steepest meridian; at 2 years, the values were 45.30 D (P = .04) and 50.21 D (P = .07), respectively. For a 3-mm pupil, there was a significant reduction (P < .05) in whole eye (total), corneal, higher-order, and astigmatic wavefront aberrations at 24 months. A significant difference (P < .05) in total coma and total spherical aberration 2 years after CXL also was observed. Mean baseline pupil center pachymetry decreased significantly (P = .04) at 6 months, but recovered by 12 months and remained stable thereafter through the 2-year follow-up. Endothelial cell counts did not change significantly (P = .32).CONCLUSIONS: CXL improved UCVA and BSCVA in the study patients, most likely by significantly reducing corneal asymmetry and corneal as well as total wavefront aberrations. (Am J Ophthalmol 2012;154:520-526. (C) 2012 by Elsevier Inc. All rights reserved.)