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Rodrigo A. Quesada, MD
Gabriel Quesada, MD
Kevin L. Waltz, MD, OD
Epithelial and total corneal thickness profiles were measured in vivo with the Zeiss Cirrus HD-OCT 5000 across the central 6- to 10-mm diameter. Maps of 20 keratoconic eyes and 20 normal eyes were obtained. The average, standard deviation, minimum, maximum, and range of epithelial, and total corneal thickness were plotted. The average location of the thinnest epithelium, thinnest stroma, and thinnest total cornea were found. These points were correlated with anterior and posterior elevation of the topography ( using Galilei G6)
The corneal epithelium of the normal eyes has an average central thickness of 53.4 microns. It is, on average, 5.7 u thicker in its lower half than in the upper half, and 1.2 microns thicker nasally than temporally, The average epithelial thickness profile in keratoconus showed an epithelial doughnut pattern characterized by localized central thinning surrounded by an annulus of thick epithelium. The thinnest epithelium was displaced on average by 0.51 ± 0.66 mm temporally and 0.34 ± 0.65 mm inferiorly with reference to the corneal vertex.
Mapping of the corneal epithelial help in early diagnosis of keratoconus. In keratoconus, the typical epithelium remodels following a characteristic pattern. There is a centralized area of thinning surrounded by a ring of thicker epithelium. The epithelial thickness profile can help exclude a keratoconus even if there is a suspicious topography.
Seyed Javad Hashemian, MD
To assess the visual and refractive outcomes and tomographic changes after implantation of a single-segment intrastromal corneal ring (ICRS; Intacs® SK) in the early stages of Keratoconous.
One segment Intacs SK was inserted using a femtosecond laser into eyes with stage I–II Keratoconous. Visual and refractive outcomes and corneal tomography changes were analyzed 6 months postoperatively.
The study evaluated 155 eyes of 123 patients. At six months the SE,mean sphere, and mean cylinder were decreased by 0.97, 1.22, and 1.29 diopters (D), respectively. The mean preoperative uncorrected UDVA and CDVAincreased from 0.78 to 0.39 and from 0.45 to 0.18 LogMAR respectively. Steep and Flat Keratometry, Mean K and anterior and posterior best feet sphere decreased significantly, 94.0% of eyes gained one or more lines of CDVA.
Implantation of one segment Intacs SK is safe and effective to treat early Keratoconous leading to significant improvement in UDVA, CDVA, and refractive error.
Shady T. Awwad, MD
Karim Kozhaya, MD
Nour Aloyoun Nasser, MS
Anais Salloukh, MD\
To retrospectively evaluate the visual, refractive, and tomographic results of intracorneal ring segments (ICRS) insertion in keratoconus eyes with previous history of corneal cross-linking (CXL) as compared to virgin eyes
A retrospective analysis of 228 eyes with mild to moderate Keratoconus eyes who underwent ICRS. Only 30 eyes underwent previous CXL, hence the rest of the eyes were matched according to this group, based on type and segment size, age, SimK, Kmax, pachymetry, topographic and manifest astigmatism, and manifest spherical equivalent refraction. The final comparison groups were 60 virgin keratoconus eyes and 30 post-CXL keratoconus eyes. Primary outcome measures preoperatively, and at 1, 3, and 6 months postoperatively, included uncorrected and distance-corrected visual acuity (UCVA and DCVA), manifest sphere and cylinder, Simk and Kmax, and corneal higher order aberrations.
The LogMAR UCVA for the ICRS and ICRS-CXL groups improved from 0.74 ± 0.23 to 0.37 ± 0.27, and 0.61 ± 0.27 to 0.41 ± 0.29 respectively, while LogMAR CDVA improved 0.43 ± 0.20 to 0.15 ± 0.19, and 0.31 ± 0.16 to 0.10 ± 0.12 respectively, (P<0.01), and Kmax improved from 53.57 ± 4.16 D to 49.64 ± 4.06 D and 53.59 ± 4.85 D to 49.09 ± 5.23 D, respectively (P<0.01). Manifest cylinder improved from 3.31 ± 1.50 D to 1.56 ± 1.33, and 3.76 ± 1.28 D to 1.01 ± 0.87 D, respectively (P<0.01). SimK changed from 45.88 ± 1.96 D to 44.46 ± 2.28 D, and 45.5 ± 3.08 D to 44.21 ±3.09 D. No clinically relevant intraoperative or postoperative complications were observed in either group.
Corneal ring segments insertion in keratoconus eyes with previous corneal cross-linking have similar visual, refractive, and topographical results as virgin eyes.
Nigel H. Barker, FRCOphth
To report our experience of scleral contact lenses in the management of Keratoconic patients, some of whom would have had either Corneal Collagen Cross Linking (CXL) or Penetrating Keratoplasty (PKP).
66 eyes of the 44 patients with Keratoconus were fitted with scleral contact lenses (SCL) at least 3 months post-CXL and at least 1 year post-PKP. Data analysis included age, sex, maximum Keratometry Values (Kmax), best corrected visual acuity with spectacles (BCVA-S) and best corrected visual acuity with SCL (BCVA-SCL). Data were collected prospectively.
CXL was performed on 29 % of the eyes and PKP was performed on 11% of the eyes. The mean age of patients was 31 years and 77% of the patients were female. The mean BCVA-S of the 66 eyes was 0.5 in logarithm and improved to 0.1 with SCL. Mean Kmax value was 56.65 diopteres. Mean BCVA-S for Corneal transplant patients was 0.7 and VA significantly improved to 0.3 with SCL. Mean BCVA-S for CXL patients was 0.5 and VA remarkably improved to 0.1 with SCL.
All reported eyes achieved significant improvement in the BCVA with SCL. SCLs should be considered lenses of choice in management of keratoconus and corneal transplant patients.
Jack Parker, MD, PhD
John Parker, MD
Korine van Dijk, BScOptom, PhD
Rénuka S. Birbal, MD
Silke Oellerich, PhD
Gerrit RJ. R. Melles, MD, PhD
Isabel Dapena, MD, PhD
Philip W. Dockery, MPH
To question the consensus on the mechanism for corneal hydrops in eyes with keratoconus (KC).
Sixteen eyes of 10 patients with comorbid keratoconus (KC) and Fuchs endothelial dystrophy underwent uncomplicated DMEK, and 5 consecutive eyes of 5 patients with KC alone underwent Bowman layer (BL) transplantation, complicated by inadvertent perforation of the posterior corneal stroma and Descemet membrane (DM). The presence or absence of hydrops was assessed by intra- and postoperative optical coherence tomography and slit-lamp biomicroscopy.
None of the 16 DMEK eyes manifested a hydrops at any time during or after surgery. By contrast, all 5 eyes undergoing BL transplantation complicated by posterior corneal perforation demonstrated hydrops, evident intra- and postoperatively.
In eyes with KC, even the complete removal of DM was insufficient to produce hydrops, whereas a combined defect in DM and the posterior corneal stroma consistently elicited this pathology.