Purpose To establish the effect of systemic oxidative stress on the pathogenesis of keratoconus by measuring serum total oxidant status (TOS) and total antioxidant status (TAS) in patients with keratoconus. Methods Twenty-five patients with keratoconus (keratoconus group) and 25 age-sex-matched healthy subjects (control group) were enrolled in the study. Exclusion criteria were smoking habit, history of any other corneal pathology, systemic disease or inflammation, and current antioxidant or anti-inflammatory therapies. All participants underwent a detailed ophthalmological examination and corneal topography. Serum samples were obtained from all participants. Oxidative stress markers (TAS and TOS) were measured using a commercial kit and oxidative stress index (OSI) was calculated. Results The study comprised 25 patients with keratoconus (mean age of 26.4 ± 1.7 years) and 25 healthy control subjects (mean age of 26.6 ± 1.7 years) (P40.05). The serum TOS and OSI values were significantly higher in patients with keratoconus compared with those of the controls (P ¼ 0.036 and 0.037, respectively). However, serum TAS did not show significant difference between the keratoconus and control groups (P ¼ 0.497). Conclusions The higher levels of serum oxidant status and OSI in patients with keratoconus suggest that systemic oxidative stress might be involved in the pathogenesis of keratoconus.

Purpose To assess the effects of preoperative patient characteristics on clinical outcomes of corneal crosslinking (CXL) treatment in patients with progressive keratoconus. Methods This retrospective study comprised 96 eyes of 96 patients who had unilateral CXL treatment for progressive keratoconus. All patients underwent a complete ophthalmological examination and corneal topography at baseline and 1 year. Subgroup analyses were performed according to the age (o30 andZ30 years), gender, preoperative corrected distance visual acuity (CDVA, o0.3 and Z0.3 logMAR (log of the minimum angle of resolution)), preoperative maximum keratometry (K, o54 and Z54 D), baseline topographic cone location (central, paracentral, and peripheral), and preoperative thinnest pachymetry (o450 and Z450 mm) to determine the associations between preoperative patient characteristics and outcomes (changes in visual acuity and maximum keratometry) of CXL treatment. Results In the entire study population, mean CDVA and maximum K significantly improved after CXL treatment (Po0.001). Patients with a preoperative CDVA of 20/40 Snellen equivalent or worse (Z0.3 logMAR) experienced more visual improvement after CXL treatment (Po0.001). However, an age Z30 years and a baseline thinnest pachymetry less than 450 mm were found significantly associated with more flattening in maximum keratometry (P ¼ 0.024, P ¼ 0.005 respectively). Gender, preoperative maximum K, and baseline topographic cone location did not show significant effect on postoperative visual acuity and maximum keratometry (P40.05). Conclusions In patients with progressive keratoconus, age, baseline visual acuity, and baseline thinnest pachymetry seem to affect the success of the CXL treatment.

Purpose: To assess the diagnostic values of corneal epithelial and stromal thickness distribution characteristics in forme fruste keratoconus (FFKC) and subclinical keratoconus (KC). Methods: This cross-sectional study was conducted at VISSUM Innovation and Miguel Hernandez University, Alicante, Spain. Twenty-seven eyes (27 subjects) with FFKC, 50 eyes (50 subjects) with subclinical KC with a best spectacle corrected distance visual acuity ≥20/20 (Snellen) (grade zero KC according to the Red Temática de Investigación Cooperativa en Salud classification), and 66 control eyes (66 subjects) were included. Epithelial and stromal thicknesses and epithelium/stroma (E/S) thickness ratio at center, thinnest point, 5-, and 8-mm circles obtained from the MS-39 device (CSO, Firenze, Italy) were compared among the control, FFKC, and subclinical KC groups. Results: The FFKC group had thinner 8-mm superior-nasal epithelium and higher central E/S ratio compared with the control group (P < 0.05). In the subclinical KC group, the E/S ratios in the 5-mm temporal and superior zones were higher than those in the control group (P < 0.05). The FFKC and subclinical KC groups had thinner stroma compared with the control group (P < 0.05). A two-parameter formula correctly classified 94% of the eyes with subclinical KC and 98.5% of the normals, whereas another three-parameter model had 75% sensitivity and 94.3% specificity for discriminating FFKC from normals. Conclusions: This study identified different epithelial distributional and behavioral patterns in eyes with FFKC and subclinical KC. Eyes with FFKC seem to have increased central E/S ratio and asymmetric superior-nasal epithelial thinning, whereas keratometric and volumetric alterations seem to be more prominent in subclinical KC.

Background/Objectives To investigate effects of microalbuminuria (MA), diabetes duration, glycosylated haemoglobin (HbA1c) level, hypertension (HT) and/or hyperlipidaemia (HL) coexistence on retinal layers in diabetic patients without diabetic retinopathy (DR) using spectral-domain optical coherence tomography (SD-OCT). Subjects/Methods This cross-sectional study involved 95 (45 had MA and 50 had no MA) patients with type 2 diabetes mellitus (DM) without DR and 91 age-and gender-matched non-diabetic controls. Macular and peripapillary SD-OCT measurements (Heidelberg Engineering GmbH, Heidelberg, Germany), DM duration, HbA1c levels and presence of HT and/or HL were used for statistical analyses. ResultsThe MA (+), MA (−) and control groups had similar age and gender distribution (p > 0.05). The differences in SD-OCT measurements among the MA (+), MA (−) and control groups were insignificant (p > 0.05). However, diabetic patients (n = 95) had significantly thinner inferior-temporal peripapillary retinal nerve fibre layer (RNFL) (p = 0.042) than in the controls (n = 91). Superior peripapillary RNFL was significantly thinner in patients with an HbA1c level > 7% (p = 0.049). However, 3 mm-nasal, temporal and superior perifoveal thicknesses were significantly lower in patients with DM duration over 10 years (p < 0.05). HT and/or HL coexistence did not lead a significant difference in SD-OCT parameters among the groups. Conclusions In diabetic patients without DR, peripapillary inferior-temporal RNFL thinning might be an early sign of neuroretinal degeneration and it seems to be independent from vascular endothelial damage (MA). Poor metabolic control appears to lead superior peripapillary RNFL thinning, while perifoveal thicknesses tend to decrease with longer DM duration.