Search

Purpose To develop an algorithm for the Fourier analysis of posterior corneal videokeratographic data and to evaluate the derived parameters in the diagnosis of Subclinical Keratoconus ( SKC) and Keratoconus ( KC). Methods This was a cross-sectional, observational study that took place in the Eye Institute of Thrace, Democritus University, Greece. Eighty eyes formed the KC group, 55 eyes formed the SKC group while 50 normal eyes populated the control group. A self-developed algorithm in visual basic for Microsoft Excel performed a Fourier series harmonic analysis for the posterior corneal sagittal curvature data. The algorithm decomposed the obtained curvatures into a spherical component, regular astigmatism, asymmetry and higher order irregularities for averaged central 4 mm and for each individual ring separately (1, 2, 3 and 4 mm). The obtained values were evaluated for their diagnostic capacity using receiver operating curves ( ROC). Logistic regression was attempted for the identification of a combined diagnostic model. Results Significant differences were detected in regular astigmatism, asymmetry and higher order irregularities among groups. For the SKC group, the parameters with high diagnostic ability ( AUC > 90%) were the higher order irregularities, the asymmetry and the regular astigmatism, mainly in the corneal periphery. Higher predictive accuracy was identified using diagnostic models that combined the asymmetry, regular astigmatism and higher order irregularities in averaged 3and 4 mm area ( AUC: 98.4%, Sensitivity: 91.7% and Specificity:100%). Conclusions Fourier decomposition of posterior Keratometric data provides parameters with high accuracy in differentiating SKC from normal corneas and should be included in the prompt diagnosis of KC. [ABSTRACT FROM AUTHOR]

. Purpose: To evaluate the diagnostic capacity of the Ocular Response Analyser's keratoconus match index (KMI) and keratoconus match probability (KMP) classification in a sample of keratoconus (KC) patients. Methods: Keratoconus match index and KMP from 114 KC eyes, randomly selected from 114 patients with bilateral keratoconus (KCG), were compared with the corresponding ones from 109 normal eyes (CG). Keratoconus match index's predictive accuracy was assessed by receiver operating curves (ROC). Keratoconus match probability level of agreement was evaluated at the different KC stages of the Amsler-Krumeich classification. Correlations were estimated with topographic keratoconus classification (TKC), keratoconus index (KI), index of surface variance (ISV), vertical asymmetry (IVA), height asymmetry (IHA), height decentration (IHD), minimal radius (Rmin), central corneal thickness (CCT), thinnest corneal thickness (TCT) mean keratometry (Km) and intraocular pressure (IOPg). Results: Mean KMI in KCG and CG was 0.20 ± 0.38 and 0.98 ± 0.25, respectively (p < 0.01). Significant KMI differences (p < 0.01) were detected in different KC groups [range: 0.62 ± 0.38 (KC 1), −0.62 ± 0.04 (KC 4)]. Significant correlation was detected between KC staging and KMI ( r = −0.56, p < 0.0001). Keratoconus match probability identified 22.03% of the CG eyes as suspect. Moreover, KMP identified 7.01% and 23.68% of the KCG eyes as normal and suspect, respectively. Receiver operating curves analysis for KMI parameter indicated a predictive accuracy of 97.7% (cut-off point: 0.512, sensitivity: 91.18%, specificity: 94.34%). Conclusions: Keratoconus match index seems to be a reliable index in keratoconus diagnosis and staging. Keratoconus match probability identifies a significant percentage of topographically defined KC and CG eyes as suspect. Diagnostic capacity of these novel indexes needs to be further explored. [ABSTRACT FROM AUTHOR]

. Purpose: To assess the efficacy of the Allegretto Wave and the wavefront-optimized ablation profile (WFO) in non-anterior astigmatism correction, in both LASIK and photorefractive keratectomy (PRK) treatments. Methods: Seventy-four refractive surgery candidates were recruited prospectively in a non-randomized trial. Only one eye from each candidate was randomly enrolled in the study. Of them, 40 eyes underwent LASIK treatment (LG group), while 34 eyes underwent PRK treatment (PG group). Preoperatively, the ocular residual astigmatism (ORA) was calculated for each eye, according to which each astigmatism fault was characterized as primarily anterior or non-anterior. Twenty LG eyes and 16 PG eyes presented primarily anterior astigmatism (LG-A and PG-A subgroups, respectively), while 20 LG eyes and 18 PG eyes demonstrated primarily non-anterior astigmatism (LG-NA and PG-NA subgroups, respectively). Postoperatively, vector analysis of astigmatism correction was conducted. The following indexes were calculated: (i) correction index (CI), (ii) difference vector (DV) and (iii) index of success (IOS). Results: Preoperatively, mean differences between manifest and topographic astigmatisms for the LG and the PG subgroups were significant (p:0.006 and p < 0.001, respectively), while postoperatively, aforementioned differences were non-significant (p:0.18 and p:0.09, respectively). Regarding vector analysis in the LG group, mean CI, IOS and DV were 1.39 ± 1.26, 0.37 ± 1.06 and 0.30 ± 0.51, respectively. Differences in CI, IOS and DV between LG-A and LG-NA subgroups were non-significant. Regarding vector analysis in the PG group, mean CI, IOS and DV were 1.22 ± 0.33, 0.47 ± 0.46 and 0.27 ± 0.25, respectively. Differences in CI, IOS and DV between PG-A and PG-NA subgroups were non-significant. Conclusions: Our results suggest that the Allegretto Wave and WFO profile seem to be equally effective in both anterior and non-anterior astigmatism correction, regardless of treatment type. [ABSTRACT FROM AUTHOR]

A bstract Background: To evaluate the level of agreement between intended and measured ablation of the wavefront optimize profile corrected by the Wellington nomogram in myopic spherocylindrical corrections and assess its impact on refractive outcomes. Design: Prospective, university-institute setting. Participants: Eighty-six participants (86 eyes for photorefractive keratectomy group) and 86 participants (86 eyes for laser in situ keratomileusis group) recruited in a consecutive-if -eligible basis. Methods: Differences between intended and measured ablation were evaluated with Scheimpflug camera. Refractive outcomes were evaluated by means of postoperative spherical equivalent, postoperative defocus equivalent, contrast sensitivity, correction index, difference vector and index of success. Main Outcome Measures: Correlation of visual outcomes with intended ablation. Results: Both groups demonstrated significant over-ablations (16.7 ± 8.5, P < 0.001 & 11.8 ± 18.5, P < 0.001, respectively). Intended ablation was the primary determinant of the measured difference ( r-square 0.769 & 0.765, respectively). Photorefractive keratectomy corrections over 100 µ had significant impact on postoperative spherical equivalent, postoperative defocus equivalent, correction index, difference vector and index of success ( P = 0.044, P = 0.05, P = 0.019, P = 0.016, P = 0.006, respectively), but laser in situ keratomileusis corrections over 100 µ had significant impact only on postoperative defocus equivalent, difference vector and index of success ( P = 0.04, P = 0.05). Conclusions: The results suggest that the wavefront optimize profile seems to over-ablate corneal tissue both in photorefractive keratectomy and laser in situ keratomileusis. Over-ablation exerts significant impact on refractive outcomes only in high spherocylindrical corrections. [ABSTRACT FROM AUTHOR]

Purpose: To study the effects of maximum dynamic physical exercise on retrobulbar blood flow and ocular perfusion pressure (OPP). Methods: Thirty male subjects undergoing routine periodic medical evaluation were included. All participants underwent cardiac stress test according to a standard protocol. Before the test, the intraocular pressure was measured and colour Doppler imaging was performed with a 7.5 MHz linear probe, to record peak systolic velocity (PSV), end diastolic velocity and resistivity index at the ophthalmic artery (OA), central retinal artery (CRA) and nasal and temporal branches of short posterior ciliary arteries (SPCA). The same measurements were repeated 1 and 30 min after the test. Results: OPP and PSV at the OA were significantly higher at the 1-min interval, compared with the pretest scores ( P = 0.01, in both cases), whereas the respective differences on the 30-min interval were statistically not significant. On the contrary, PSV at the CRA and SPCA were not significantly changed on the same intervals. Differences between pretest and post-test scores for end diastolic velocity and resistivity index were statistically not significant for all examined vessels. Conclusions: Maximal physical exercise increases OPP and blood flow at the OA without affecting blood flow at the CRA and SPCA, implying that auto-regulative mechanisms are active in both retinal and choroidal circulations. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study is to examine the repeatability of Pentacam-derived anterior chamber volume measurements, and assess the level of agreement of anterior chamber volume measurements obtained with the Visante and the Pentacam imaging devices. Methods: Anterior chamber volume was calculated with the Pentacam device and the Visante using the Wang formula. Results were analysed by means of the Wilcoxon signed rank test, Bland-Altman analysis, Cronbach's alpha test and intraclass correlation coefficient. P-values <0.01 were considered statistically significant. Results: One randomly selected eye from each of 20 persons was analysed. Spherical equivalent ranged between −2.50 and +1.50 D, and their age ranged from 25 to 79 years (mean ± SD: 54.4 ± 19.2 years). Mean anterior chamber volume measured with Pentacam was 171.1 ± 39.6 µL (minimum: 103.0 µL, maximum: 236.0 µL), and mean anterior chamber volume measured by Visante was 171.4 ± 42.4 µL (minimum: 96.4 µL, maximum: 245.5 µL). There was no statistically significant difference between Pentacam and Visante measurements of the anterior chamber volume ( P = 0.691, Wilcoxon signed rank test). Cronbach's alpha and intraclass correlation coefficient for Pentacam were 0.998 and 0.991, respectively. Conclusions: Anterior chamber volume measurements obtained with the Visante using the Wang formula were in good agreement with the corresponding ones obtained with Pentacam. This recently described method is easy to perform and might contribute to both clinical and research settings. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented related to the relationship between visual ability and visual fields.

A letter to the editor is presented related to glaucoma-bound quality of life studies and its clinical significance.

To describe a case of conjunctival hyperaemia and proptosis of the right eye.Three-dimensional computed tomography (CT) was performed to reveal the size and position of a lesion of osseous density extending into the right orbit. The lesion was then excised using a right paranasal transcutaneous approach.The pathology report suggested ethmoidal osteoma. The postoperative course was uncomplicated and the lesion did not recur during a 5-year follow-up period. Repeated postoperative ophthalmic examinations revealed preservation of visual acuity and visual fields postoperatively.Diagnosis is based on imaging studies, especially CT and three-dimensional CT scans. A three-dimensional CT scan is critical in understanding the actual dimensions of the tumour and its relations with other structures. Surgical removal is indicated in cases with orbital matrix compression and displacement. A transcutaneous paranasal approach allows for increased exposure of affected structures. [ABSTRACT FROM AUTHOR]