Ocular, corneal, and internal aberrations in eyes with keratoconus, forme fruste keratoconus, and healthy eyes.

PURPOSE: The purpose of this study is to evaluate ocular, corneal, and internal aberration parameters in eyes with keratoconus (KC), forme fruste keratoconus (FFKC), and normal eyes. METHOD: In a prospective study, one eye of 110 patients with KC, 60 FFKC patients, and 150 healthy participants was evaluated using OPD-Scan II. Ocular, corneal, and internal higher-order aberrations were measured through a sixth-order Zernike polynomial decomposition. Receiver operating characteristic analysis was performed to evaluate the diagnostic ability of the aberration parameters in discriminating KC and FFKC from normal eyes. RESULTS: The root mean square of the all ocular aberration measurements was significantly higher in the KC and FFKC patients than that of normal participants (p < 0.05). All of the corneal aberration measurements were significantly higher in KC patients than those of normal patients (p < 0.05); however, only corneal total higher-order aberration (HOA), vertical and total coma, and higher-order astigmatism were significantly higher in the FFKC patients than normal participants (p < 0.05). The results also showed that internal aberration lower-order astigmatism, total trefoil, and total higher-order spherical aberration were significantly different between KC and normal groups (p < 0.05). In comparison, internal total HOA, lower and higher-order astigmatism, total trefoil, and vertical coma were significantly different between FFKC and normal groups (p < 0.05). Ocular vertical and total coma had the highest ability in discriminating keratoconic from normal eyes. Ocular total higher aberration and total coma had the highest diagnostic ability in discriminating FFKC from normal eyes. The diagnostic ability of internal aberration, on the other hand, was moderate to poor in discriminating KC and FFKC from normal eyes. CONCLUSION: Ocular aberration especially vertical and total coma and total HOA were found to be suitable parameters to discriminate KC and FFKC from normal patients. These two parameters could be used as discriminating factors in evaluating the patient for refractive surgery in an attempt to avoid iatrogenic ectasia.

Is keratoconus more severe in pediatric population?

PURPOSE: To compare the ophthalmic parameters and the severity of keratoconus (KC) in pediatrics and adults at the time of initial diagnosis in an Iranian population. METHODS: KC was diagnosed via slit-lamp examination and Pentacam imaging. In a retrospective observational study, consecutive patients were divided into two groups of pediatrics (<18 years old) and adults (>18 years old). Topographic, keratometric, and tomographic parameters, and severity of KC at the time of diagnosis were compared in both groups. Severity of KC was classified according to Amsler-Krumeich classification. RESULTS: One hundred fifty-eight eyes of 158 pediatric patients and 343 eyes of 343 adults with KC were studied. The mean ages of the pediatric and adult patients were 15 ± 1.9 and 22 ± 1.9 years, respectively (p < 0.001). The results revealed that pediatric patients had significantly higher values of anterior and posterior mean, flat and steep keratometry, astigmatism, and maximum elevation and significantly lower central and thinnest corneal thickness (p < 0.05). No significant difference was found regarding sphere, cylinder, manifest refraction spherical equivalent, and uncorrected and best-spectacle corrected visual acuity between the groups (p > 0.05). Pediatric patients had a significantly more severe KC than adult patients according to Amsler-Krumeich classification (p = 0.001). CONCLUSION: Our findings suggest that KC is more severe in pediatrics, hence the fact that they should be closely monitored and intensively treated.

Clinical biomicroscopy and retinoscopy findings of keratoconus in a Middle Eastern population.

BACKGROUND: The present work was conducted to investigate the prevalence of clinical biomicroscopy and retinoscopy findings of corneas with keratoconus (KC) at first presentation and their relationship with disease severity. METHOD: In a prospective cross-sectional study, 371 consecutive KC patients were examined by slitlamp biomicroscopy and retinoscopy at the time of diagnosis. This research evaluates the prevalence of clinical findings such as a corneal protrusion, Vogt's striae, Fleischer's ring, Munson's sign, Rizzuti's sign, corneal scars, as well as any additional KC signs such as prominent nerve fibres, scissoring reflex and Charleaux 'oil droplet' sign on retinoscopy. Keratometry (mean K), central and thinnest corneal thickness (CCT and TCT), anterior and posterior elevation (AE and PE), and astigmatism by means of Pentacam, and visual acuity (VA) were recorded for each patient. The severity of KC was graded on the basis of the Keratoconus Severity Score. RESULTS: Corneal protrusion, scissoring reflex, corneal thinning, Fleischer's ring, and prominent nerve fibres were the most prevalent findings in the keratoconic corneas (71.7 per cent, 64.2 per cent, 56.6 per cent, 55.5 per cent and 54.7 per cent, respectively). Those KC patients with these clinical findings had significantly higher mean K, AE and PE, while having significantly lower CCT, TCT and VA compared to those who did not present these signs (p < 0.05). The presence of clinical findings was associated with more severe disease (p < 0.001, all comparisons). Wearing contact lenses was associated with the increase in the risk of corneal scarring (p = 0.009, odds ratio = 1.761, 95 per cent confidence interval = 1.126 to 2.755). CONCLUSION: This study provided information regarding the presence of the clinical slitlamp biomicroscopic and retinoscopic findings with severity of KC. A positive association was found between the presence of clinical signs and topographic parameters. In addition, wearing contact lenses was associated with the increase in the risk of corneal scarring.

Prevalence of Eyelid Laxity and its Association with Ophthalmic Findings and Disease Severity in Patients with Keratoconus.

PURPOSE: To investigate the prevalence of eyelid laxity and quantify eyelid measurements in normal and keratoconic eyes and the correlations of these findings with ophthalmic parameters and disease severity in patients with keratoconus (KC). METHODS: In a prospective case-control study, prevalence of eyelid laxity and eyelid measurements were evaluated in 53 patients with KC and the same number of matched healthy controls. The eyelid measurements were compared between the groups, as well as mean keratometry (K), central and thinnest corneal thickness (CCT and TCT), astigmatism, manifest refraction spherical equivalent (MRSE), best spectacle-corrected visual acuity (BCVA), and severity of KC according to the Keratoconus Severity Score. RESULTS: Prevalence of eyelid laxity was 71.7% (38 patients) in patients with KC and 20.8% (11 patients) in normal participants (p<0.001, odds ratio 9.673 [95% confidence interval 3.959 to 23.631]). Comparison of the eyelid measurements in the patients with KC with and without eyelid laxity revealed significantly higher measurements of anterior eyelid distraction test, Hertel exophthalmometry measurements, lateral canthal angle to orbital rim and tendon movement, palpebral fissure width, retraction test (lower eyelid), and vertical lid pull (upper eyelid) in patients with KC with eyelid laxity (p<0.05). No significant difference was found regarding mean K, CCT, TCT, astigmatism, MRSE, or BCVA values of the patients with KC with and without eyelid laxity (p>0.05). Moreover, severity of KC was not associated with the presence of eyelid laxity or eyelid measurements (p>0.05). CONCLUSIONS: Higher prevalence and greater eyelid laxity were found in patients with KC compared to healthy participants. However, eyelid laxity was not associated with severity of KC.

Maternal Morbidities and Occurrence of Intraventricular Hemorrhage in Preterm Infants.

Intraventricular hemorrhage (IVH) is one of the most serious neurological morbidities in preterm infants. Several prenatal, intrapartum, and neonatal risk factors have been detected in different studies. However, maternal conditions that may render the neonates to IVH have been the subject of very few studies. Preterm infants with and without IVH were included in the study, and maternal obstetrics and general health clinical files were reviewed for any kind of morbidity. Data were then analyzed with statistical software to assess the association between maternal conditions and IVH. A total of 115 neonates with IVH and 120 infants without IVH were recruited. Among all maternal conditions, prolonged rupture of membrane (p = 0.00), laparoscopic surgery for infertility (p = 0.001), and in vitro fertilization (IVF) (p = 0.00) increased the risk of IVH in neonates significantly. IVF remained strongly associated with IVH even after controlling for confounding variables (odds ratio: 9.75; confidence interval: 2.66-35.75; p = 0.001). Based on our findings, prolonged rupture of membrane and IVF were maternal conditions that increased the risk of IVH. Laparoscopic surgery for infertility was also associated with an increased risk of IVH.

Corneal cross-linking treatment of keratoconus.

Keratoconus as the most common cause of ectasia is one of the leading cause of corneal transplants worldwide. The current available therapies do not modify the underlying pathogenesis of the disease, and none of the available approaches but corneal transplant hinder the ongoing ectasia. Several studies document Crosslink defect between collagen fibrils in the pathogenesis of keratoconus. Collagen cross link is a relatively new approach that with the application of the riboflavin and ultraviolet A, new covalent bands reform. Subjective and objective results following this method seem to be promising. Endothelial damage besides other deep structural injury, which is the major concern of this technique have not yet been reported, when applying the standard method.

Gene therapy in keratoconus.

Keratoconus (KC) is the most common ectasia of the cornea and is a common reason for corneal transplant. Therapeutic strategies that can arrest the progression of this disease and modify the underlying pathogenesis are getting more and more popularity among scientists. Cumulating data represent strong evidence of a genetic role in the pathogenesis of KC. Different loci have been identified, and certain mutations have also been mapped for this disease. Moreover, Biophysical properties of the cornea create an appropriate candidate of this tissue for gene therapy. Immune privilege, transparency and ex vivo stability are among these properties. Recent advantage in vectors, besides the ability to modulate the corneal milieu for accepting the target gene for a longer period and fruitful translation, make a big hope for stupendous results reasonable.

Higher order aberration comparison between two aspherical intraocular lenses: MC6125AS and Akreos advanced optics.

AIM: To compare higher order aberrations in two aspherical intraocular lenses (IOLs): Akreos advanced optics (AO) and Dr. Schmidt Microcrystalline 6125 aspheric anterior surface (MC6125AS) with each other. METHODS: Forty eyes of 39 patients underwent phacoemulsification and Akreos AO and MC6125AS were implanted in their eyes in a random manner. Three months post-operatively, higher order aberrations including spherical aberration, coma aberration, and total aberrations were measured and compared. RESULTS: The total aberration was 0.24±0.17 in eyes with Dr. Schmidt and 0.20±0.01 in eyes with Akreos AO (P=0.361). The mean of coma aberration was 0.17±0.21 and 0.09±0.86 in Dr. Schmidt and Akreos lenses, respectively (P=0.825). Total spherical aberration was almost the same in both groups (Mean: 0.05, P=0.933). Best corrected visual acuity in Akreos AO (0.10±0.68) and Dr. Schmidt (0.09±0.67) did not differ significantly (P=0.700). CONCLUSION: There is no statistically significant difference in the higher order aberrations between these two aspherical lenses.