PurposeFour cases of corneal ectasia after small-incision lenticule extraction (SMILE) have been reported. In this review, we provide an overview of the published literature on corneal ectasia after SMILE and risk factors associated with this complication.MethodsCase reports were identified by a search of seven electronic databases for pertinent heading terms between 2011 and July 2017. We identified patient characteristics and surgical details including preoperative topography, central corneal thickness, and anterior keratometry (Km). Residual stromal bed (RSB) values not reported were computed using VisuMax ReLEx SMILE software Version 2.10.10. Preoperative ectasia risk was measured using the Randleman Ectasia Risk Score System (ERSS). Percent tissue alteration was calculated for each patient as described by Santhiago et al.ResultsSeven eyes of four patients developed corneal ectasia post SMILE. Two patients had abnormal topography in both eyes. One patient had abnormal topography in one eye. Only one patient was noted to have normal topography in both eyes and later developed ectasia in one eye in the absence of any known risk factors. The mean Randleman ectasia risk score was 4±3 (range: 1–8). The mean calculated percent tissue altered (PTA) was 38%±6% (range: 30%–47%).ConclusionA majority of reported ectasia cases occurred in patients with subclinical keratoconus. These conditions may be exacerbated by SMILE and should be considered absolute contraindications to the procedure. Three patients were identified to have high risk based on the ERSS, and one patient exhibited a PTA ≥40%. We formulated a modification to the current calculation of PTA that takes into account the differences in tissue altered between SMILE and laser in situ keratomileusis (LASIK). More studies are needed to fully quantify the risk of ectasia. For now, we propose adopting the same exclusion criteria used for LASIK in the SMILE procedure until more specific metrics have been validated.
The recent emergence of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its resultant human disease, COVID-19, will likely have a significant impact on the corneal tissue donor pool. Current recommendations from the United States and global eye bank associations call for the outright avoidance of tissues from donors recently infected with or exposed to COVID-19. This conservative recommendation is currently appropriate given the reported ocular sequelae, tear film viral detectability, and transmissibility of COVID-19. However, the rapidly increasing global prevalence and mortality of COVID-19 threatens the tenability of current tissue exclusion guidelines, and may necessitate their relaxation in the near future.
PurposeTo assess longitudinal refractive, keratometric, and topographic changes following KAMRA small-aperture inlay implantation.Design and settingProspective study at a single site refractive surgery center.MethodsFifty patients underwent KAMRA small-aperture corneal inlay implantation for the correction of presbyopia. Uncorrected near visual acuity (UNVA), uncorrected distance visual acuity, manifest refractive spherical equivalent (MRSE), mean keratometry (Km), corneal topography, and surgically induced astigmatism vector analysis assessments were performed preoperatively and at 1, 3, 6, 12, 24, and 36 months postoperatively.ResultsThe study comprises 50 eyes. An average shift of 0.15±0.63 D (range −1.63 to 2.00 D) occurred between preoperative baseline and 36 months. At 36 months, 54% of patients had hyperopic MRSE and 40% had myopic MRSE compared with baseline. Km was significantly elevated at all postoperative measurements compared with baseline, with the largest Km measured at 12 months. Eighty-six percent of patients had UNVA of 20/32 or better and 88% uncorrected distance visual acuity of 20/25 or better at 36 months. Longitudinal corneal topography revealed a pattern of corneal steepening over the body of the inlay and flattening over the aperture, correlating with a hyperopic shift. There was no significant surgically induced astigmatism.ConclusionKAMRA inlay may cause an increase in Km compared with baseline. Corneal steepening may occur in a specific pattern with steepening over the inlay and flattening over the aperture. This topographic pattern causes a hyperopic shift, which may be relevant for subsequent procedures, such as cataract extraction.
Both devices can be considered safe and effective, however, the results of corneal inlay implantation are mixed, and long-term patient satisfaction will likely depend on subjective expectations about the capabilities of the inlays. Variability in surgical technique and postoperative care within and between the two clinical trials diminishes the comparative power of this article.
Background: Creutzfeldt-Jakob disease (CJD) is a rare, fatal, neurodegenerative prion disease potentially transmissible through corneal transplantation. While statistical analyses performed two decades ago estimated the overall prevalence of CJD in the corneal donor pool to be low, the recent significant increase in corneal Digital Features To view digital features for this article go to
This article reviews the current literature pertaining to rainbow glare (RG), including incidence rate, clinical presentation, etiology, prognosis, and management. RG is a rare optical complication of femtosecond laser-assisted in situ keratomileusis that results in patients seeing an array of spectral bands surrounding point sources of light under mesopic and scotopic conditions. The mechanism is thought to be a consequence of the formation of a transmissive diffraction grating on the posterior surface of the corneal flap created by the FS laser. RG has a good prognosis and is usually self-limiting. Persistent RG with concomitant residual refractive error may warrant lifting the flap and photoablating the posterior surface of the flap. Patients with persistent RG and no residual refractive error should be considered candidates for phototherapeutic keratectomy on the posterior flap surface.
PurposeThe aim of this study was to compare stereoacuity before and after KAMRA corneal inlay implantation for the correction of presbyopia.Patients and methodsThis is a prospective study of 60 patients who underwent KAMRA inlay implantation. Patients were examined before and 6 months after surgery for stereoacuity, uncorrected distance visual acuity (UDVA), and uncorrected near visual acuity (UNVA).ResultsThe mean stereoacuity before surgery was 29.5±28.1 arcsec (range: 20–200) and at 6 months was 29.8±26.4 arcsec (range: 20–200). The decline in stereoacuity was not statistically significant. At 6 months follow-up, UDVA was 20/25 or better in all 60 patients and UNVA was J2 (20/25) or better in 51 (85%) patients.ConclusionThere is no significant change in stereoacuity following KAMRA inlay implantation. The KAMRA inlay is a good treatment option for improving near vision in presbyopic patients while preserving stereoacuity and distance vision.
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