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Purpose: To analyze the relationship between the seasonal allergic conjunctivitis (SAC), eotaxin-2, matrix metalloproteinase-9 (MMP-9), and the topographical findings in the keratoconus patients., Methods: Thirty-four eyes of patients without SAC (Group 1), 34 eyes of patients with SAC (Group 2), and 20 eyes of control subjects (control group) were enrolled. Tear samples of the subjects were collected by Schirmer method. Corneal topography parameters, tear MMP-9, and tear eotaxin-2 levels were analyzed., Results: The mean tear MMP-9 levels in Groups 1 and 2 were significantly higher than in the control group (p = 0.004). MMP-9 level exhibited a positive correlation with the keratoconus stage and a negative correlation with the thinnest corneal thickness (r = 0.294, p = 0.018, and r = - 0.302, p = 0.006, respectively). The tear eotaxin-2 level was higher in Group 2 than in Group 1 and control group which is not statistically significant (p = 0.17)., Conclusion: The tear eotaxin-2 did not exhibit any difference in the presence of keratoconus. The tear MMP-9 level was higher in the keratoconic eyes, and it showed a correlation with the stage of the disease and the corneal thickness.

Purpose: To compare the 24 month visual, refractive, topographic and aberrometric results of the accelerated and standard corneal collagen cross-linking (CXL) in pediatric keratoconus patients., Methods: 87 eyes of 64 consecutive keratoconus patients under 18 years old with 24 month follow-up period following standard or accelerated CXL were included. 38 eyes received standard CXL (3 Mw/cm 2 , 30 min), while 49 eyes had accelerated CXL (9 mW/cm 2 , 10 min). Changes in the uncorrected (UCVA) and best corrected visual acuity (BCVA), spherical equivalent (SE), manifest astigmatism (MA), corneal topographic parameters, and corneal aberrations such as spherical aberration (SA), high order aberrations (HOAs), horizontal and vertical coma were evaluated. Corneal haze was graded and progression rate was assessed., Results: The difference between baseline and 24 months postoperative UCVA, BCVA, SimK (keratometry)-1, SimK-2, Kmax, and the corneal aberrations were not significantly different between the two groups (p > 0.05 for all). The mean reduction in thinnest corneal pachymetry from baseline to 24 months after CXL was higher in accelerated CXL group (p = 0.007). The progression rate was 13.1% in standard and 16.3% in accelerated group (p = 0.754). There were no differences in the grade of corneal haze between the two groups (p = 0.249). No complications were observed in the both groups., Conclusion: The 24 month results of accelerated and standard CXL revealed that, the efficacy and safety of accelerated CXL were the same with standard CXL in pediatric keratoconus patients. As being a rapid procedure, accelerated CXL appears to be more benefical for pediatric patients., (Copyright © 2018 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: The aim of this study was to evaluate the corneal biomechanical parameters in patients with ankylosing spondylitis (AS) and to compare them with the healthy subjects., Methods: Sixty patients with AS (study group) and 60 healthy subjects (control group) were enrolled in this prospective study. The study group was further classified as active (n:30) and inactive (n:30). After detailed ophthalmological examination including intraocular pressure (IOP) measurement with Goldmann applanation tonometer (IOPGAT), corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated IOP (IOPcc), and Goldmann-correlated IOP (IOPg) were measured with the Reichert Ocular Response Analyzer (ORA). Central corneal thickness (CCT) was measured with the Spectral-Domain Optical Coherence Tomography (SD-OCT)., Results: The study group's mean CH, CCT, IOPg, and IOPGAT values were lower than the control group (p < 0.05 for all variables). The mean CH, CRF, CCT, IOPg, and IOPGAT values were higher in active patients when compared to the inactive ones (p < 0.001, p < 0.001, p = 0.013, p = 0.021, and p = 0.002, respectively)., Conclusions: AS patients have lower CCT, CH, IOPg, and IOPGAT when compared with healthy subjects. In the active stage of AS, patients present with higher levels of corneal biomechanical parameters with thicker corneas. IOPcc is a more accurate measurement than IOPGAT or IOPg in AS patients.

Purpose: To evaluate the effects of three different silicone hydrogel contact lenses (SHCL), (balafilcon A, senofilcon A, and comfilcon A) on tear function tests, corneal thickness, and ocular surface cytology in first time contact lens users., Materials and Methods: In this prospective study, 120 eyes of 60 subjects were evaluated. Balafilcon A users were designated as group 1, senofilcon A users as group 2, and comfilcon A users as group 3. In all cases, before and after 6 months of contact lens wear, ocular surface disease index score (OSDI), tear breakup time (TBUT), Schirmer 1 test, central corneal thickness (CCT), central corneal epithelium thickness (CCET), and conjunctival impression cytology samples were evaluated., Results: In group 1, 40 eyes of the 20 patients, in group 2, 40 eyes of the 20 patients, and in group 3, 40 eyes of the 20 patients were evaluated. The mean OSDI scores did not differ between the three groups after contact lens wear (p > 0.05). In group 1 and group 2, significant decrease was found in the mean TBUT 6 months after contact lens wear (p = 0.04, p < 0.001, respectively). In group 3, after 6 months of contact lens wear, the mean Schirmer 1 tear test was decreased significantly (p = 0.021). In all 3 groups, no significant change was observed in the mean CCT and CCET after contact lens wear (p > 0.05). After 6 months, the morphological changes in temporal and superior conjunctival epithelial cells were found to be significant in all groups (p < 0.001)., Conclusion: Six months after SHCL wear, marked morphological changes occurred in the conjunctival epithelium. Tear function tests were also affected, while corneal thickness did not show any significant difference.

Objective: To investigate corneal biomechanical properties among individuals with unilateral nonarteritic anterior ischemic optic neuropathy (NAION) compared to healthy gender- and age-matched subjects., Methods: The study subjects were separated into 2 groups: 66 eyes of 33 patients with unilateral NAION (study group) and 33 eyes of 33 healthy individuals (control group). Reichert ocular response analyzer (Reichert Ophthalmic Instruments) was used to assess corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), and Goldmann-correlated intraocular pressure values. Also, central corneal thickness was measured using Scheimpflug camera combined with a Placido disc corneal topographer (Sirius; Costruzioni Strumenti Oftalmici)., Results: Mean CH and median CRF values were significantly lower in the affected eyes (8.8 ± 1.8 mm Hg, 9.4 mm Hg, respectively) and contralateral unaffected eyes (9.1 ± 1.6 mm Hg, 9.8 mm Hg, respectively) of NAION patients than those in the control group (9.9 ± 1.3 mm Hg, 10.4 mm Hg, respectively; all P < 0.017). Mean IOPcc was significantly higher in the affected eyes of NAION patients (19.2 ± 3.5 mm Hg) than in the eyes of control group (17.1 ± 3.6 mm Hg; P = 0.002)., Conclusions: CH and CRF are significantly reduced in patients with NAION, possibly indirectly reflecting structural weakness in the lamina cribrosa.

Purpose: To investigate the variations in biomechanical properties of the cornea in rheumatoid arthritis (RA) patients., Methods: A total of 53 RA patients, and 25 healthy individuals (control group) were enrolled. Rheumatoid arthritis patients were classified as in active phase (group 1; n=24) or in remission phase (group 2; n=29). Corneal biomechanical parameters including corneal hysteresis (CH), corneal resistance factor (CRF), corneal compensated intraocular pressure (IOPcc), and Goldmann-correlated IOP (IOPg) were measured with the Reichert Ocular Response Analyzer. Topographical measurements, including central corneal thickness (CCT), anterior chamber depth, iridocorneal angle, and corneal volume were measured using a Sirius corneal topographer., Results: The mean CH was 9.43±1.17 mm Hg in group 1, 9.42±1.84 mm Hg in group 2, and 10.47±1.68 mm Hg in the control group (P=0.03). The mean IOPcc was 17.85±3.2 mm Hg in group 1, 17.95±3.49 mm Hg in group 2, and 15.36±3.11 mm Hg in the control group (P=0.008). The CH showed a significant positive correlation with CRF (P=0.000, r=0.809) and CCT (P=0.000, r=0.461), and a significant negative correlation with IOPcc (P=0.000, r=-0.469)., Conclusions: Decrease in the mean CH measurements indicates that ultrastructural changes in the cornea may occur in the active phase, and these changes persist in the remission period. In addition, IOPcc is significantly affected by the corneal biomechanical properties. In RA patients, it is important to control the corneal parameters and IOP measurements against the irreversible changes on the optic nerve.

Objective: To investigate the effects of corneal epithelium on corneal curvature in patients with keratoconus., Design: This is a prospective, nonrandomized study., Participants: Fifty-nine eyes of 47 patients diagnosed as keratoconus and for whom corneal collagen crosslinking (CXL) was recruited in this study., Methods: This study is a single-center clinical trial. Pregnancy, lactation, connective tissue disease, corneal thickness below 350 μm, severe dry eyes, or scar of corneal surgery were exclusion criteria. Before and during CXL procedure after removing the corneal epithelium, maximum values of corneal apical curvature, simulated keratometry 1 (Sim-K1), simulated keratometry 2 (Sim-K2), temporal and inferior curvature values, all of which are 1.5 mm from the corneal center, were calculated. These values before and after removal of epithelium were compared statistically., Results: Mean age of patients was 23.30 ± 5.5 (12-38) years. Twenty-eight (59%) were male while 19 (41%) were female. Mean values measured before and after removing the corneal epithelium were: apical curvature; 59.19 ± 7.2 (47.06-82.40) diopter (D) and 61.70 ± 8.8 (49.19-92.66) D (p = 0.001), SimK1; 47.57 ± 4.3 (39.14-64.57) D and 48.23 ± 4.3 (41.89-66.70) D (p = 0.001), SimK2; 52.04 ± 5.3 (43.56-69.34) D and 53.34 ± 5.6 (43.73-70.89) D (p = 0.001), inferior curvature; 53,85 ± 5.2 (43.47-76.56) D and 55.05 ± 5.8 (44.56-81.93) D (p = 0.002), temporal curvature 49.49 ± 5.1 (41.50-71.03) D and 51.53 ± 5.4 (41.58-73.34) D (p = 0.001), respectively., Conclusions: In keratoconus patients during CXL treatment, after removing the corneal epithelium, more steepness is detected in the curvature of the steeper area of the cornea. When evaluating patients with keratoconus, the masking effect of corneal epithelium on values of curvature should be taken into consideration.

Purpose: The aim of this study was to evaluate the effects of pterygium surgery on the corneal topography and anterior chamber parameters using a Pentacam system., Methods: Prospective clinical study. Scheimpflug camera was performed in 21 eyes of 21 patients with primary pterygium, both before and 2 months after pterygium excision using conjunctival autograft technique. The topographic parameters such as total mean refractive power, index of surface variance, aberration coefficent, anterior chamber depth, anterior chamber angle were evaluated. The best corrected visual acuity (BCVA) changes were also noted. Differences between preoperative and postoperative values were compared., Results: The mean refractive power was 42.59 ± 3.44 dioptry (D) preoperatively and 43.72 ± 2.07 D postoperatively (p = 0.154). The mean preoperative index of surface variance was 72.24 ± 48.72. It was decreased to 32 ± 23.13 after surgery (p = 0.003). The mean aberration coefficent was 3.04 ± 1.27 preoperatively. It was decreased to 2.4 ± 1.06 postoperatively (p = 0.017). The preoperative and postoperative values of the mean anterior chamber depth were 2.91 ± 0.49 mm and 2.91 ± 0.52 mm, respectively (p = 0.638). The mean preoperative anterior chamber angle was 33.13 ± 6.89°. It was measured as 32.77 ± 4.86° postoperatively (p = 0.779). The mean overall preoperative BCVA was logMar 0.13 ± 0.29. It was significantly improved to logMar 0.0238 ± 0.07 after pterygium surgery (p = 0.011)., Conclusions: Corneal topographic changes induced by pterygium are almost reversible after surgical treatment of the pterygium. Pterygium surgery significantly improves the BCVA, and decreases the aberration coefficient and index of surface variance; however, it does not have any effect on the anterior chamber parameters.

Purpose: To measure the lower tear meniscus dynamics with Fourier domain-optical coherence tomography (FD-OCT) in keratoconus patients without dry eye findings to evaluate the effects of the corneal ectasia on lower tear meniscus parameters, and to determine the most affected meniscus variable from the corneal ectasia in keratoconus., Methods: Prospective, clinical study. Forty-one eyes of 25 keratoconus patients without dry eye and 40 eyes of 20 healthy subjects were included. The lower tear meniscus analysis with FD-OCT, and corneal topography, keratometry, and pachymetry measurements were performed in all eyes. The main outcomes, including the lower tear meniscus height (TMH), depth (TMD), area (TMA), and angle between cornea and the tear meniscus (α-angle), were assessed. The results were compared between the patients and the control subjects., Results: The average keratometric power was 53.94 ± 5.76 D (between 44.46 to 63.75 D) in keratoconic eyes. It was 43 ± 0.8 D (between 40.50 to 45.94 D) in the controls. The average TMH, TMD, and TMA values did not show any statistically significant difference between the patients and the controls (p = 0.39, p = 0.824, p = 0.516, respectively). However, the average value of the α-angle was significantly higher in keratoconic eyes when compared to controls (p = 0.031). It was positively correlated with the keratometric power (r = 0.577, p = 0.001)., Conclusions: The TMH, TMD, and TMA did not show any change with the corneal protrusion; however, the α-angle had positive correlation with the keratometric power in keratoconic eyes.

Purpose: To compare heme oxygenase 2 (HO-2) enzyme levels detected by immunohistochemical staining methods in the cornea epithelium obtained from keratoconus patients and normal subjects. Materials and Methods: The keratoconus group included 69 eyes of 69 patients with keratoconus scheduled for cross-linking surgery. The control group included 52 eyes of 52 patients with refractive error scheduled for photorefractive keratectomy surgery. After a detailed ophthalmologic examination, corneal topographic maps of each patient were generated, and then the patients underwent surgery. The corneal epithelium was collected mechanically during the surgery, fixed with formalin, embedded in paraffin blocks, and sectioned by microtomes. HO-2 antibodies were applied to the samples for immunohistochemical evaluation. The intensity of the staining was identified as negative, weak, moderate or strong. The keratoconus group was classified as early (average keratometry (AvrK) ≤ 47 D), moderate (AvrK 47-55 D) and advanced keratoconus (AvrK ≥ 55 D). Finally, intergroup and intragroup comparison analyses were made statistically. Results: In the keratoconus group, 20 (29%) (14 weak and 6 moderate staining) of the 69 corneal epithelial specimens were identified with HO-2 expression. In the control group, 40 (76.9%) (16 moderate and 24 strong staining) of the 52 corneal epithelial specimens were identified with HO-2 expression. HO-2 expression in the corneal epithelial specimens was significantly less in the keratoconus group than in the control group (p < 0.001). There was no substantial difference among the keratoconus subgroups in terms of staining with the HO-2 antibody (p = 0.797). Conclusions: The HO-2 enzyme staining using immunohistochemical methods was at lower amounts in the keratoconic corneal epithelial cells as compared with normal corneal epithelial cells. The HO-2 enzyme may play a role in the etiopathogenesis of keratoconus. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of corneal epithelium on corneal curvature in patients with keratoconus.Design:This is a prospective, nonrandomized study.Participants:Fifty-nine eyes of 47 patients diagnosed as keratoconus and for whom corneal collagen crosslinking (CXL) was recruited in this study.Methods: This study is a single-center clinical trial. Pregnancy, lactation, connective tissue disease, corneal thickness below 350 μm, severe dry eyes, or scar of corneal surgery were exclusion criteria. Before and during CXL procedure after removing the corneal epithelium, maximum values of corneal apical curvature, simulated keratometry 1 (Sim-K1), simulated keratometry 2 (Sim-K2), temporal and inferior curvature values, all of which are 1.5 mm from the corneal center, were calculated. These values before and after removal of epithelium were compared statistically.Results: Mean age of patients was 23.30 ± 5.5 (12–38) years. Twenty-eight (59%) were male while 19 (41%) were female. Mean values measured before and after removing the corneal epithelium were: apical curvature; 59.19 ± 7.2 (47.06–82.40) diopter (D) and 61.70 ± 8.8 (49.19–92.66) D (p = 0.001), SimK1; 47.57 ± 4.3 (39.14–64.57) D and 48.23 ± 4.3 (41.89–66.70) D (p = 0.001), SimK2; 52.04 ± 5.3 (43.56–69.34) D and 53.34 ± 5.6 (43.73–70.89) D (p = 0.001), inferior curvature; 53,85 ± 5.2 (43.47–76.56) D and 55.05 ± 5.8 (44.56–81.93) D (p = 0.002), temporal curvature 49.49 ± 5.1 (41.50–71.03) D and 51.53 ± 5.4 (41.58–73.34) D (p = 0.001), respectively.Conclusions: In keratoconus patients during CXL treatment, after removing the corneal epithelium, more steepness is detected in the curvature of the steeper area of the cornea. When evaluating patients with keratoconus, the masking effect of corneal epithelium on values of curvature should be taken into consideration. [ABSTRACT FROM PUBLISHER]

Purpose To compare the complications occurring within the first 3 months of corneal collagen crosslinking (CXL) performed with mechanical or transepithelial phototherapeutic keratectomy (PTK) epithelial removal in keratoconus patients. Setting Yildirim Beyazit University Ataturk Training and Research Hospital, Ankara, Turkey. Design Nonrandomized retrospective clinical study. Methods Eyes of consecutive progressive keratoconus patients who had PTK or mechanical epithelial removal followed by CXL were included. All patients were examined regularly until epithelial healing. Detailed ophthalmologic examinations were performed preoperatively and 1 and 3 months postoperatively. Results The study comprised 499 eyes (302 patients) that had transepithelial PTK (Group 1, 153 eyes) or mechanical epithelial removal (Group 2, 256 eyes) followed by CXL. Delayed epithelial healing occurred in 15.0% of eyes in Group 1 and 3.5% of eyes in Group 2 ( P = .001). Epithelial hypertrophy occurred in 24.8% of eyes and 3.5% of eyes, respectively ( P = .001). Salzmann-like epithelial nodules (2.6%), epithelial herpetic keratitis (1.9%), anterior uveitis (1.9%), and elevated intraocular pressure (1.9%) occurred in Group 1 only and infective keratitis (0.8%) in Group 2 only. Marked stromal edema and peripheral sterile infiltrates occurred at similar rates in both groups ( P = .567 and P = .479, respectively). Grade 1+ corneal haze was significantly high in Group 2. Grade 2+ and 3+ haze was significantly high in Group 1 ( P = .001). Conclusions Ocular surface healing disorders were the most common early complications of CXL. Short-term complications were higher with the transepithelial PTK epithelial removal technique than with mechanical epithelial removal. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned. [ABSTRACT FROM AUTHOR]

PurposeMethodsResultsConclusionThis study aimed to evaluate the tomographic, biomechanical, and in vivo confocal microscopic (IVCM) effects of chronic gout disease on human cornea.This prospective study included 60 eyes of 30 participants with chronic gout disease and 60 eyes of 30 healthy controls. Corneal thickness, keratometry (K) readings, and corneal aberrations were measured with Sirius 3 D corneal tomography system (Sirius, CSO, Italy). Corneal biomechanical properties (corneal hysteresis [CH], corneal resistance factor [CRF], and intraocular pressure [IOP] parameters) were assessed with an ocular response analyzer (ORA, Reichert Ophthalmic Instruments). The number and morphology of corneal endothelial cells and the number of basal epithelial cells were evaluated with IVCM (Confoscan 4.0). Tear breakup time (TBUT) was also evaluated.The mean diagnosis time of the patients with gout was 91.2 ± 69.6 months (12–300 month). Among corneal tomography measurements, K readings were similar between the two groups, while total and higher-order aberrations(coma, trefoil,s pherical, and quadrafoil) were significantly higher in the gout group. In the evaluation of biomechanical measurements, the CH value was significantly lower and the corneal-compensated IOP value was significantly higher in the gout group (p = 0.02, p = 0.01, respectively). The two groups did not significantly differ regarding the CRF or Goldmann IOP (p = 0.61, p = 0.15, respectively). Among the IVCM parameters, the number of corneal basal epithelial cells and the percentage of corneal endothelial hexagonality were significantly lower in the gout group, but no significant difference was detected in terms of the number of endothelial cells or polymegathism (p = 0.02, p < 0.001, p = 0.18, p = 0.59, respectively). While TBUT was significantly lower in the gout group (p < 0.001).This study showed that chronic gout disease increases the corneal aberrations and decreases the basal epithelial cell count, hexagonality ratio of endothelial cell and corneal biomechanics. [ABSTRACT FROM AUTHOR]