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Background : The accurate evaluation of corneal thickness (CT) post small incision lenticule extraction (SMILE) is clinically relevant to reduce the risk of complications. We aimed to analyze repeatability and agreement of central corneal thickness (CCT), thinnest corneal thickness (TCT), and mid-peripheral corneal thickness (MPCT) measurements using Scheimpflug imaging, anterior segment swept-source optical coherence tomography (AS-SS-OCT, CASIA 1000, Tomey), and ultrasound pachymetry (USP, SP-3000, Tomey) in eyes with previous SMILE. Methods : Ninety-one eyes of 91 patients were included. Within-subject standard deviation (Sw), test-retest repeatability (TRT), intraclass correlation coefficient (ICC), and coefficient of variation (CoV) were used to evaluate repeatability. Agreement was assessed by repeat-measurement analysis of variance and Bland-Altman analysis. Results : The above three instruments revealed that Sw was <5.91 µm, CoV was <1.08%, TRT was <16.38 µm, and ICC was >0.94. The 95% limits of agreement were relatively narrow and Bland-Altman plots were more concentrated at the CCT, at the TCT, and at the CT 2mm . However, it was shown to be wide at the CT 5mm . Conclusions : The three devices provide good repeatability of CT measurements in patients who undergone SMILE. Agreement between measurements at the CCT, TCT, and CT 2mm were high, but measurement agreements among CT 5mm revealed poor agreement.

Purpose: To determine the percentage of contribution of the magnitude of posterior corneal astigmatism to total corneal astigmatism using Scheimpflug imaging., Methods: This prospective cross-sectional study was conducted on 356 eyes of 356 patients, where the total corneal astigmatism was calculated by addition of anterior and posterior corneal astigmatism using vector analysis and then the percentage of posterior to total corneal astigmatism was calculated., Results: The percentage of contribution of posterior to total corneal astigmatism was about 30% in patients with With The Rule astigmatism and about 8% in patients with Against The Rule astigmatism., Conclusion: Posterior corneal astigmatism should not be neglected during calculation of total corneal astigmatism as neglecting posterior corneal astigmatism can result in errors during calculation and correction of astigmatism., Competing Interests: None of the authors have any financial interest in any product or material used in this study. No competing financial interests exist. The authors report no conflicts of interest for this work., (© 2020 Hosny et al.)

Purpose: To validate an animal model of corneal stromal opacity by using objective vision-independent in vivo imaging metrics., Methods: This was a prospective study, with two arms: (i) observational human arm which included 14 patients with healed unilateral ulcerative keratitis; and (ii) experimental rabbit arm, which included 6 New Zealand white rabbits. A 3-mm central wound was created in the left eye of the rabbits by manually removing 200-250 μm of the superficial stroma, followed by rotating-burr application. Both groups underwent photography, high-resolution anterior segment optical coherence tomography, and Scheimpflug imaging using similar diagnostic platforms and standardized image capturing protocols. Parameters studied were relative change in (i) corneal thickness; (ii) corneal epithelial: stromal (E:S) reflectivity ratio; (iii) corneal stromal light scattering using densitometry; and (iv) central corneal keratometry., Results: In the experimental arm, there was a significant decrease in corneal thickness (273 ± 51.3 vs. 407.3 ± 10.3 μm, p = 0.0038), E:S reflectivity ratio (0.71 ± 0.09 vs. 0.99 ± 0.06, p = 0.0018), and keratometry (40.4 ± 2.3 vs. 45.8 ± 0.9D, p = 0.0033) and increase in densitometry (54.2 ± 11.65 vs.18.7 ± 3.8 GSU, p = 0.0001) from baseline, which stabilized at 4 to 8-weeks post-wounding (p > 0.3632). At 8-weeks, the relative change from baseline in corneal thickness (28.4 ± 13.5% vs.22.4 ± 13%, p = 0.368), E:S reflectivity ratio (28.1 ± 11.5% vs. 30.6 ± 8.9%, p = 0.603), corneal densitometry (204.17 ± 97.3% vs. 304.9 ± 113.6%, p = 0.1113), and central corneal keratometry (13.6 ± 6.9% vs. 18.9 ± 7.4%, p = 0.1738) in rabbits was similar to human corneal scars., Conclusion: The animal model of corneal opacification was objectively comparable to human post-keratitis scars and can be valuable for in vivo evaluation of emerging therapies for corneal opacities., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Aim: To evaluate detailed anterior segment parameters of patients with idiopathic inflammatory myopathies (IIM), including polymyositis (PM), and dermatomyositis (DM), and to clarify the associations between these data and clinical variables of IIM., Methods: Totally 57 PM, 41 DM patients and 62 controls were enrolled in this cross-sectional, observational, case-control study. All study participants underwent Pentacam evaluation. Laboratory investigations consisted of different antibody assays, while extramuscular clinical assessments included Raynaud's phenomenon, dysphagia, interstitial lung disease, arthritis/arthralgia, and weight loss. Objective signs and subjective symptoms of dry eye disease (DED) were also evaluated., Results: All pachymetric parameters [center, apex, thinnest and maximal keratometry (K max )] and corneal volume (CV) of both sides of PM patients proved to be significantly lower. Some pachymetric data were also noticed as significantly decreased compared to those of controls. Several significant differences were traced between anterior segment values and extramuscular manifestations of myositis, largely in case of arthritis/arthralgia and weight loss, whereas associations between anterior segment parameters and antibodies were weak. Objective clinical tests of DED were also significantly decreased in IIM patients., Conclusion: The results suggest that all IIM patients have thinner corneas compared with those of controls, and decreased corneal parameters are significantly associated with the occurrence of some extramuscular manifestations. In addition, IIM patients tend to develop objective signs of DED., (International Journal of Ophthalmology Press.)

Purpose: To identify patterns of age-, gender- and refractive- related changes in Scheimpflug-based anterior chamber depth across the central 8 mm of chamber width, to derive normative models, potentially useful for angle closure disease diagnosis., Methods: This was a retrospective, cross-sectional study. Scheimpflug photography was used to obtain anterior chamber depth measurements at 57 points across the central 8 mm of the chamber width from one eye of each healthy subject (male Caucasians (n = 189), female Caucasians (n = 186), male Asians (n = 165) and female Asians (n = 181)). Sliding window and nonlinear regression analysis was used to identify the age-related changes in chamber depth. Hierarchical cluster analysis was used to identify test locations with statistically identical age-related shifts, which were used to perform age-correction for all subjects, resulting in normative distributions of chamber depth across the chamber width. The model was examined with and without the contribution of spherical equivalent refractive error., Results: Distinct clusters, demonstrating statistically indistinguishable age-related changes of chamber depth over time, were identified. These age-related changes followed a nonlinear regression (fifth or sixth order polynomial). Females tended to have a greater rate of chamber depth shallowing. Incorporating refractive error into the model produced minimal changes to the fit relative to the ground truth. Comparisons with cut-offs for angle closure from the literature showed that ageing alone was insufficient for identifying angle closure disease., Conclusions: Age-, ethnicity- and gender-related differences need to be acknowledged in order to utilise anterior chamber depth data for angle closure disease diagnosis correctly. Ageing alone does not adequately account for the angle closure disease process., (© 2020 The Authors. Ophthalmic and Physiological Optics published by John Wiley & Sons Ltd on behalf of College of Optometrists Ophthalmic & Physiological Optics.)

Aim: To measure lens densities with a Pentacam HR device in patients with active uveitis. Measurements were taken at the onset of the attack and after the treatment of inflammation., Methods: The study included 51 eyes with different anterior uveitis aetiologies and a control group of 48 eyes of age- and gender-matched healthy subjects. Lens densitometry measurements were taken with a Scheimpflug camera on a Pentacam HR device. All the examinations and measurements were performed on the first presentation with the onset of the attack and were repeated at 1st and 3rd months after treatment. Lens densitometry measurements were compared with those of the healthy control group and the healthy fellow eyes of the uveitic patients., Results: No statistically significant difference was determined between the groups in respect of age and gender (p > 0.05). At 3 months, Pentacam densitometry of zones 3 value was determined to be significantly high in the uveitic eyes compared to the healthy eyes (p = 0.018). The average lens density value (ALD) at 1 month was statistically significantly higher than the baseline value in the uveitic eyes (p = 0.034). There was no significant change in the ALD value at 3 months compared to the baseline and 1-month values (p = 0.386, p = 0.736, respectively)., Conclusion: Even if there is no cataract development that can be clinically observed in eyes with anterior uveitis, lens density in zone 3 showed a significant increase at the end of 3 months compared to the baseline value. This change can be evaluated objectively with Scheimpflug imaging.

Purpose: To define diurnal changes in anterior segment parameters of keratoconus patients by using Scheimpflug imaging., Methods: All keratoconus patients had corneal topography measurements 3 times a day (around 09:00 AM, 13:00 PM and 17:00 PM) by the same experienced operator. Three consecutive scans in each measurement session were obtained. The average of three measurements was used for analysis. A repeated measures analysis of variance with one within-subject factor (time of day) was carried out to assess diurnal variation., Results: This study included 26 eyes of 26 patients with keratoconus. Significant diurnal variation was found in CCT and TCT measurements (P < 0.01, and P < 0.01, respectively). The mean amplitudes of change in CCT and TCT were 4.2 ± 1 µm (95% CI: 1.7-6.8 µm) and 4.1 ± 1.1 µm (95% CI: 1.2-8.0 µm), while the mean of CCT and TCT were 462.4 ± 34.5 µm (95% CI: 448.4-476.6 µm) and 452.9 ± 6.6 µm (95% CI: 439.3-466.5 µm), respectively. The maximum value and the lowest value were observed at 09:00 AM and at 17:00 PM, respectively. Other parameters except CCT and TCT did not show diurnal variation., Conclusion: Statistically significant but clinically insignificant diurnal variation in CCT and TCT measurements of the keratoconus patients were detected over an 8-hour period (09:00 AM-17:00 PM).

Purpose: Rigid gas-permeable (RGP) contact lens fitting after penetrating keratoplasty (PK) is challenging due to significant irregular astigmatism. The aim of the study was to determine a guideline for selecting the initial base curve (BC) of the RGP contact lens fitting in post PK eyes., Methods: The data of patients who had tricurve RGP contact lens fitting post PK were collected retrospectively. The following data were collected: best-corrected visual acuity with glasses and contact lenses; contact lens parameters which included the BC and diameter; corneal topography parameters which included steep keratometry value (K), flat-K, and mean-K; and anterior best fit sphere (BFS) measured using Scheimpflug imaging., Results: The median age of the 40 subjects (46 eyes) who met the inclusion criteria was 37.5 years (IQR 26.7-45.5). The spherical equivalent was -3.00 diopter (D) (-8.31 to -1.56). The median steep-K, flat-K, and mean-K in them were 6.76 mm (6.28-7.07), 7.78 mm (7.37-8.14), and 7.26 mm (6.93-7.46), respectively. The median anterior BFS value of the transplanted cornea was 6.96 mm (6.6-7.37). The median BC of the final RGP lens was 7.0 mm (6.7-7.23) and the median diameter was 9.8 mm (9.4-10.4). Among all the Scheimpflug imaging parameters, the BFS correlated well with the final BC of the RGP contact lens dispensed (R 0.742, P < 0.0001)., Conclusion: The anterior corneal surface BFS value can be used as a reference in selecting the initial BC of tricurve RGP contact lens to achieve the best fitting and reducing the chair time of patients after PK., Competing Interests: None

Purpose: To assess whether combined analysis of specular microscopy and Scheimpflug imaging improves detection of an upcoming allograft rejection following Descemet membrane endothelial keratoplasty (DMEK)., Methods: Retrospective analysis of 22 eyes that had developed a clinical proven allograft rejection 28 (±22) months (range: 4-84 months) after DMEK. Specular microscopy and Scheimpflug images routinely made after DMEK were retrospectively analysed for changes in endothelial cell morphology (e.g. nuclear activation), cell density (>10%) and pachymetry (>7%), and/or the presence of subclinical keratic precipitates. The same parameters were evaluated for 22 control eyes matched for age, gender and surgery indication., Results: A total of 20/22 eyes (91%) showed detectable changes 0.25-75 months before allograft rejection became clinically manifest: 13/22 (59%) showed both specular microscopy and Scheimpflug imaging changes; 5/22 (23%) only had changes on Scheimpflug imaging; and 2/22 (9%) only had specular microscopy changes. In 18/22 (82%) and 14/22 (64%) eyes, subclinical keratic precipitates and endothelial cell morphology changes could be detected, respectively. A total of 11/22 (50%) eyes concurrently showed a >10% drop in endothelial cell density and 4/22 (18%) a >7% pachymetry increase. Of the control eyes, 7/22 (32%) showed changes with specular microscopy but not with Scheimpflug imaging., Conclusions: Combined analysis of specular microscopy and Scheimpflug imaging may allow recognizing an upcoming allograft rejection in over 90% of eyes and up to 6 years before rejection becomes clinically manifest. Early recognition of eyes at risk may allow for targeted intensified steroid treatment to prevent endothelial cell damage associated with rejection., (© 2019 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Purpose: To assess the role of Scheimpflug imaging in improving the accuracy of reference marking for toric IOL implantation., Methods: In this prospective, randomized, clinical trial all patients with cataract and pre-existing significant regular corneal astigmatism, who required implantation of a toric IOL were included in the study, and patients with any ocular pathology or abnormality were excluded. Patients were divided into two groups: For one group of patients, Group I (GI), reference marking was finalized using slit lamp only, and for the second group, Group II (GII), after slit lamp marking, the reference marks were checked using Goniometer of Scheimpflug imaging. The primary outcome was to determine the axis of toric intraocular lens (IOL) postoperatively (within 1 hour) and compare it with the desired axis of placement., Results: We found a statistically significant difference in the two groups (P < 0.001) suggesting Group II (4 step technique) is better than Group I (3 step technique)., Conclusion: Scheimpflug imaging, an extra step preoperatively, is an effective measure to reduce errors in reference marking and thereby improving the refractive outcome of toric intraocular lens., Competing Interests: None

Purpose : To evaluate corneal parameters in patients with polymyositis (PM) and dermatomyositis (DM) and compare them with those of healthy controls. Methods : A total of 43 PM and 32 DM patients and 93 controls were enrolled in this cross-sectional, observational, case-control study. Corneal parameters were evaluated by Pentacam. Objective clinical tests of dry eye disease (DED) were also performed. Results : All pachymetric measurements and corneal volumes (CVs) proved to be significantly lower both in PM and DM patients. The values of DM patients were closer to control values than those of the PM patients. For tear break-up time and Schirmer-I test values significant differences were observed between patients and controls, with values decreased both in PM and DM patients. Conclusions : PM patients rather than DM patients tend to develop thinner and low-volume corneas as compared to controls. Additionally, a high prevalence of DED among both PM and DM patients was also detected.

Objective: Iridocorneal angle (ICA) narrowing is a known risk factor for primary glaucoma in multiple species, but has not been described in companion rabbits. This study aimed to develop an ICA grading scheme for companion rabbits to enable early glaucoma predisposition diagnosis., Animals Studied: Twenty healthy rabbits of varying breeds and ages., Procedures: Rabbits received complete ophthalmic examinations, including gonioscopy, and imaging of the ICA using spectral-domain optical coherence tomography (SD-OCT), Scheimpflug imaging (Pentacam ® HR), and high-resolution ultrasound (HRUS). Angle opening distance (AOD) and angle recess area (ARA) of the ICA were measured and assessed for agreement using a Bland-Altman analysis. A five-stage gonioscopy grading scheme was created, and Spearman-rank test assessed for correlation between gonioscopy grades and ICA measurements. Differences among age and sex were analyzed with a nonparametric ANOVA and Wilcoxon rank-sum test, respectively., Results: Analysis revealed AOD medians of 0.28mm for SD-OCT [95% CI: 0.24-0.31], 0.20mm for Pentacam ® HR [95% CI: 0.18-0.21], and 0.25mm for HRUS [95% CI: 0.22-0.28]. The median ARA was 0.14mm 2 for SD-OCT [95% CI: 0.117-0.163], 0.09mm 2 for Pentacam ® HR [95% CI: 0.082-0.100], and 0.06mm 2 for HRUS [95% CI: 0.046-0.054]. The association between gonioscopy grade and SD-OCT ARA was significant (P < 0.05), and there was a significant difference (P < 0.001) between imaging modalities for both ARA and AOD., Conclusions: Gonioscopy grade correlated well with SD-OCT ARA. Therefore, SD-OCT is recommended as a noncontact method for evaluating companion rabbit ICA. Each imaging device should not be used interchangeably for ICA evaluation., (© 2019 American College of Veterinary Ophthalmologists.)

Corneal topography is the most widely used technology for examining the anterior corneal surface. Scheimpflug imaging is a newer technique that allows for measurement of both the anterior and posterior corneal surface, which allows for three-dimensional reconstruction of the cornea. This is of particular interest and value in the field of cataract and refractive surgery. The Galilei camera is a commercially available dual Scheimpflug system that combines curvature data from Placido disc-based corneal topography with elevation data from Scheimpflug technology. The addition of Placido disc topography makes the Galilei unique from its more popular counterpart, the Pentacam, which was discussed in Part I. Compared to the Pentacam, and however, the Galilei analyzer is a newer system that has emerged as a valuable screening tool given its dual Scheimpflug capability. In the first article of this series, the authors summarized the refractive indices available on the Pentacam system with the purpose of identifying the best diagnostic parameters for keratoconus. Similarly, the purpose of this article is to summarize corneal surface indices available on the Galilei system and evaluate their use in screening of the refractive surgery candidate. Since post-operative keratectasia is still prevalent, this paper aims to identify the most clinically relevant indices that may be used in pre-operative evaluation., Competing Interests: Ethical issues have been completely observed by the authors. All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship of this manuscript, take responsibility for the integrity of the work as a whole, and have given final approval for the version to be published. No conflict of interest has been presented. Funding/Support: None, (© 2019, Author(s).)

Purpose: To evaluate the topographic, refractive, and pachymetric changes after ethanol-assisted transepithelial corneal cross-linking (CXL) to stabilize progression of keratoconus (KC)., Patients and Methods: This study retrospectively evaluated the long-term topographic, refractive, and pachymetric changes in patients diagnosed with KC who underwent corneal cross-linking and/or intrastromal corneal ring segment (ICRS) implantation. The subjects were divided into three groups, corresponding to eyes treated with CXL alone (group 1), CXL and ICRS at the same time (group 2), and CXL after ICRS implantation (group 3). Corrected visual acuity and refraction, steep keratometry (SteepK) values, steepest keratometry reading on sagittal curvature map, and corneal thickness were recorded preoperatively and at each visit. Changes between measurements were assessed during follow-up., Results: Corrected distant visual acuity (CDVA) values improved in all groups compared with baseline, but the differences were not statistically significant except for the first year (p > 0.05). In groups 1 and 3, SteepK values did not change statistically significantly during the entire follow-up (p > 0.05). In group 2, SteepK values statistically significantly decreased at all follow-up examinations compared with baseline, determined as the first month after ICRS implantation (p < 0.05). Complication rates were acceptable without any need for surgical intervention., Conclusions: Single-session ethanol-assisted transepithelial CXL with or without ICRS implantation was a safe and effective procedure to halt progression of KC.

Background: Following new treatment options for Fuchs' endothelial corneal dystrophy, our understanding of optical and structural changes in the patient's cornea is also starting to improve., Objective: To provide an update on clinical evaluation of Fuchs' dystrophy., Material and Methods: Standardized approaches to evaluate patients with Fuchs dystrophy in routine practice and research are discussed, accounting for the progressive and partially irreversible structural changes in all corneal layers., Results: Early structural changes in the cornea can be detected before clinical edema becomes visible on slit-lamp exam. Optical limitations resulting from these structural changes can be quantified not only with high-contrast acuity but also with glare or contrast sensitivity tests. Characteristic vision-related limitations of patients with Fuchs dystrophy can, e.g., be assessed with V-FUCHS, a Fuchs dystrophy-specific "Visual Function and Corneal Health Status" instrument for patient-reported outcomes., Conclusion: Clinical grading of Fuchs dystrophy in an edematous and a non-edematous stage is outdated. Better therapy options and our improved understanding of progressive changes in the entire cornea require a standardized assessment of optical and structural changes and patient-reported limitations.

Purpose: To evaluate the capability of anterior segment Scheimpflug imaging for detecting primary angle closure disease (PACD): primary angle closure suspect, primary angle closure, and primary angle closure glaucoma, using cutoff points derived from reference databases of healthy subjects., Methods: Eighty-seven patients with PACD and 49 age-matched control subjects were included. We evaluated the sensitivity and specificity of anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA) to differentiate patients with PACD from controls. Additionally, the study's raw data was analyzed via receiver operating characteristic curves for comparison., Results: One standard deviation from the normative data's mean values was used as the cutoff point and yielded a sensitivity and specificity of 96.2% and 92.6% for ACD, 97.1% and 75.9% for ACV, and 93.3% and 72.2% for ACA, respectively. Receiver operating characteristic analysis of the raw data showed the area under the curve to be 0.984, 0.975, and 0.931 for ACD, ACV, and ACA, respectively., Conclusions: Our study demonstrated that the parameters of anterior segment Scheimpflug imaging, particularly ACD, accurately discriminate PACD. This was the first study to validate the device's normative data in a separate population. With its high reproducibility, ease of use, non-invasiveness, and speed, anterior segment Scheimpflug imaging is a potentially powerful screening tool for PACD.

Purpose: To explore anterior segment changes with keratoconus onset and progression to determine whether structural changes are predominantly corneal, limbal or both. To investigate these changes in different corneal meridians., Method: Eighty-four eyes with keratoconus and 49 healthy eyes were included in the study. Eyes with keratoconus were divided in two groups according to the Amsler-Krumeich classification: stage I and stages II-IV. Scheimpflug images at three different meridians were used to evaluate the following parameters: anterior chamber depth from the endothelium (ACD&#95;end) and corneal thickness (CT) (software provided), anterior chamber depth (ACD) and sagittal depth (SAGT) from the epithelium, and distance from the end point of SAGT to the anterior surface of the lens (DL) (measured manually), and [ACD - CT] and [SAGT - CT] (calculated). Changes in these parameters with ocular condition and meridian were analysed., Results: Statistically significant larger values were found of ACD (p = 0.012) and DL (p = 0.016) with keratoconus onset and progression, with no differences in SAGT values. Besides, [ACD - CT] and [SAGT - CT] were significantly larger in keratoconus eyes (p < 0.001 and p = 0.003, respectively). Significant differences (all p < 0.001) were found in SAGT, [SAGT - CT] and DL among meridians. Changes in these parameters with keratoconus onset and progression were similar in all meridians., Conclusion: Considering the results from the three meridians under investigation, it may be concluded that keratoconus onset has an impact on the anterior segment as a whole and not only on corneal structures. The DL distance is a useful parameter to describe limbal changes in keratoconus., (Copyright © 2018 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Background: Although ageing is the main reason for cataract progression, pseudoexfoliation syndrome (PES) represents an independent additional hazard for the development of nuclear sclerosis and cataract progression. PES can also affect corneal properties. From this perspective, this study aimed to perform a comparison of the corneal and lens densitometry measurements in eyes with PES and age-matched healthy eyes., Methods: This prospective cross-sectional study included 31 patients with unilateral PES and 40 control participants. The Pentacam HR imaging system was used to evaluate corneal densitometry (12 mm corneal diameter) and lens densitometry measurements of eyes with PES (Group 1), clinically unaffected fellow eyes (Group 2) and healthy eyes (Group 3)., Results: Eyes in Group 1 and Group 2 had statistically significantly higher corneal densitometry values for all concentric zones and layers compared with eyes in Group 3 (p < 0.05 for all). However, the results were similar when Group 1 and Group 2 were compared (p > 0.05 for all). The lens densitometry values of zone 1, zone 2 and zone 3, as well as the average lens densitometry measurements, were statistically significantly higher in Groups 1 and 2, compared with Group 3 (p < 0.05 for all). On the other hand, these parameters were similar between Groups 1 and 2 (p > 0.05 for all). Additionally, there was no significant difference between the study and control groups with regard to the maximum lens densitometry measurements (p > 0.05)., Conclusion: This study revealed that corneal and lens densitometry values of affected and fellow eyes of cases with clinically unilateral PES are significantly higher than those of healthy subjects., (© 2018 Optometry Australia.)

Background: The VX120 (Visionix Luneau, France) is a novel multi-diagnostic platform that combines Hartmann-Shack based autorefraction, Placido-disk based corneal-topography and anterior segment measurements made with a stationary-Scheimpflug camera. We investigate the agreement between different parameters measured by the VX120 with accepted or gold-standard techniques to test if they are interchangeable, as well as to evaluate the repeatability and reproducibility., Methods: The right-eyes of healthy subjects were included in the study. Autorefraction of the VX120 was compared to subjective refraction. Agreement of anterior segment parameters was compared to the Sirius (CSO, Italy) including autokeratometry, central corneal thickness (CCT), iridiocorneal angle (IA). Inter and intra-test repeatability of the above parameters was assessed. Results were analyzed using Bland and Altman analyses., Results: A total of 164 eyes were evaluated. The mean difference between VX120 autorefraction and subjective refraction for sphere, spherical equivalent (SE), and cylinder was 0.01±0.43D, 0.14±0.47D, and -0.26±0.30D, respectively and high correlation was found to all parameter (r>0.75) except for J 45 (r=0.61). The mean difference between VX120 and the Sirius system for CCT, IA, and keratometry (k1 and k2) was -3.51±8.64μm, 7.6±4.2°, 0.003±0.06mm and 0.004±0.04mm, respectively and high correlation was found to all parameter (r>0.97) except for IA (r=0.67). Intrasession repeatability of VX120 refraction, CCT, IA and keratometry yielded low within-subject standard deviations. Inter-session repeatability showed no statistically significant difference for most of the parameters measured., Conclusions: The VX120 provides consistent refraction and most anterior segment measurements in normal healthy eyes, with high levels of intra and inter-session repeatability., (Copyright © 2018. Published by Elsevier España, S.L.U.)

Purpose: Amantadine use has been temporally associated with bilateral corneal edema in a series of cases; however, its pathophysiological mechanisms have yet to be elucidated. We sought to rule out subclinical Fuchs dystrophy as a contributor, characterize its pattern of corneal edema, and describe the long-term outcome of concurrent topical steroids while resuming amantadine., Patient and Methods: After a 44-year-old woman presented with new acute onset bilateral corneal edema, amantadine was discontinued, with clinical improvement. However, neurological decompensation required restarting amantadine, which she did concurrently with topical loteprednol. To determine whether subclinical Fuchs dystrophy might be present, triplet-primed polymerase chain reaction was conducted to measure copy number of the CTG18.1 trinucleotide repeat in TCF4 . Specular microscopy and Scheimpflug imaging were conducted and followed for 32 months to assess for resolution and stability. Literature review was conducted to assess for consistency of the clinical phenotype., Results: Corneal edema resolved clinically 4 weeks after discontinuation of amantadine. Serial Scheimpflug imaging demonstrated resolution of posterior and central corneal edema and specular microscopy revealed intracellular opacities with loss of endothelial cell density. Despite resuming amantadine, Scheimpflug imaging and specular microscopy measurements remained stable at 32 months. Triplet-primed PCR of CTG18.1 in TCF4 revealed no trinucleotide repeat expansion., Conclusions: Amantadine-associated corneal edema is characteristically posterior and central and appears unlikely to represent early or subclinical decompensation of Fuchs dystrophy. We describe the unique outcome of continued corneal clearance after restarting amantadine concurrently with steroids, a pattern that has persisted over 32 months to date., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Purpose: To assess agreement of a swept source-optical coherence tomography (SS-OCT) based Biometer with a standard IOLMaster device and Scheimpflug Imaging (SI) to acquire keratometric measurements in cataract patients., Methods: In this prospective comparative study, 101 eyes of 101 cataract surgery candidates, aged 24-81 years, were sequentially examined using three devices. Keratometry values at the flat (K1) and steep (K2) axis, mean corneal power (Km) and magnitude of corneal astigmatism as well as J0 and J45 vectoral components of astigmatism obtained with the SS-OCT based biometer (IOLMaster 700) were compared with those obtained with the IOLMaster 500 and SI. The agreement between measurements was evaluated by the Bland-Altman method, intraclass correlation coefficients (ICCs) and repeated-measures analysis of variance., Results: Mean K1 values from the three devices were similar (p = 0.09). Mean K2 and Km values of IOLMaster 700 were higher than SI and lower than IOLMaster 500 (p = 0.04 for K2 and p = 0.02 for Km). There was a strong correlation between K1, K2, Km and magnitude of astigmatism obtained with all devices (r ≥ 0.80 and p < 0.01). The 95% limits of agreement (LoA) width for each keratometric value were highest for the comparison between IOLMaster 500 and SI and lowest for the comparison between IOLMaster 700 and 500. The mean differences (width of 95% LoA) for J0 and J45 vectoral components were 0.005 (2.19) and 0.12 (2.92) for the measurements obtained by IOLMaster 700 vs IOLMaster 500 and 0.06 (1.79) and 0.02 (1.58) for the measurements obtained by IOLMaster 700 vs SI, respectively., Conclusions: With ICCs close to 1, the agreement between all devices was excellent for keratometric measurements. Mean K2, Km and astigmatism measurements from IOLMaster 700 were lower than IOLMaster 500 and higher than SI. However, the differences were quite small and are not expected to affect the final IOL power.

Aim: To compare the diagnostic ability of corneal tomography and corneal dynamic response measurements in normal and keratoconus eyes., Methods: Consecutive patients with grade II-III keratoconus and age-matched normal subjects were recruited. Corneal imaging was performed using Pentacam (Oculus Optikgeräte, Wetzlar, Germany) and Corvis (Oculus Optikgeräte). A beta version of Corvis software was used with three additional parameters: maximal change of arc length, deformation amplitude (DA) ratio 1 and DA ratio 2. Diagnostic ability of both devices to differentiate normal and keratoconus eyes was evaluated using receiver-operating characteristic (ROC) curves. The areas under the ROC curve (AUC) and partial AUC (pAUC) for specificity ≥80% for each parameter of Corvis and final D value of Belin/Ambrosio Enhanced Ectasia Display (BAD) were compared., Results: Forty-two eyes of 42 patients (21 patients with keratoconus and 21 normal subjects) were included. Both groups were age matched (p=0.760). The ROC analysis showed that the final D value of BAD had the highest AUC (0.994) and pAUC (0.194). Maximum inverse radius had the highest AUC (0.954) but a relatively lower pAUC (0.158), while DA ratio 2 had the second highest AUC (0.946) together with the highest pAUC (0.177) among Corvis parameters. There was no significant difference between AUC and pAUC of BAD compared with those of DA ratio 1 (p≥0.162) and DA ratio 2 (p≥0.208)., Conclusions: The results of our study suggest that Corvis measurements have the potential to differentiate keratoconus and normal eyes. The diagnostic ability of novel parameters on Corvis was comparable to Pentacam., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Purpose: To assess corneal parameters in constitutional thinness (CT) subjects and to compare them with those of healthy individuals., Methods: Twenty-four CT subjects (BMI < 18.5 kg/m 2 ) and 24 healthy subjects (BMI: 18.5-25 kg/m2) were enrolled in this observational cross-sectional study. All participants were screened for age, gender, and medical history, then underwent a detailed ophthalmological examination. Corneal parameters were evaluated by Scheimpflug imaging. Height and weight of all subjects were measured and body mass index (BMI) was calculated., Results: The mean corneal thicknesses at the apex point, the center of pupil, the thinnest point, and the mean corneal volume were significantly lower in CT patients than those of controls. The mean intraocular pressure (IOP) was significantly lower in CTs than in controls. There was a significant correlation between BMI and IOP, and BMI was significantly correlated with all pachymetric measurements and corneal volume., Conclusion: Corneal thicknesses were significantly thinner in CT subjects compared to those in control subjects. The impact of constitutional thinness on corneal parameters should be further investigated.

Purpose: Our aim was to compare densitometry data between keratoconus and normal corneas and to assess the long-term changes in corneal backscattered light values after corneal collagen cross-linking (CXL) treatment., Material and Methods: Retrospective analysis was performed on 26 eyes of normal patients (age: 32.71 ± 12.68 years) and 39 eyes of keratoconus patients (28.93 ± 7.59 years) using the Pentacam HR corneal densitometry module before CXL and during the postoperative period, which lasted a mean of 2.53 years (range: 1-4 years). Corneal backscattered light values in grey scale unit (GSU) were recorded for the anterior 120 µm, the center layer, and the posterior 60 µm of the cornea in four concentric, central rings. An additional calculation was performed with converting GSU values to GSU/cubic millimeters (mm 3 ) with surface area calculations and using corneal thickness data., Results: Statistically significant differences were observed between normal and keratoconus group densitometry values (in GSU/mm 3 ) in all annuli of the center layer; all, but anterior layer of the 10-12 annuli; all annuli of the total thickness and in all values of the total diameter. In all these cases, the normal cornea showed higher GSU/mm 3 values compared to keratoconus corneas (p < 0.05). One month after the CXL treatment, the GSU/mm 3 data increased significantly in the anterior, the center, and the posterior zone (p < 0.05), followed by its slow decrease. At the end of the follow-up period, the GSU/mm 3 values were significantly higher in all three zones compared to those before the CXL treatment (p < 0.01)., Conclusion: Densitometry measurements can reflect the changes of optical quality of the cornea. These measurements may play a valuable role in assessing keratoconus and optical changes of the corneas after CXL treatment.

Purpose: To investigate the central and paracentral astigmatism and the significance of centration and measurement zone diameter compared to a 3-mm pupil-centred measurement zone in keratoconus and in healthy eyes., Methods: Twenty-eight right eyes from 28 KC patients with an inferotemporal cone were selected according to specified criteria based on Oculus Pentacam HR ® measurements and were matched with healthy control eyes. The flat (K1) and steep (K2) keratometry readings were registered from the 'Total Corneal Refractive Power' (TCRP) display as well as the anterior and posterior corneal astigmatism displays (ACA and PCA, respectively). Astigmatic power vectors KP0 and KP45 were calculated and analysed for a 6-mm and two 3-mm zones centred on the corneal apex and the pupil, and for 8 paracentral 3-mm zones., Results: The astigmatism was generally higher in KC. Many astigmatic values in KC differed between the 3-mm pupil-centred and the 3- and 6-mm apex-centred zones in KC. In the controls, no corresponding differences between measurement zones were seen, apart from PCA, which differed. The magnitude and direction of KP0 and KP45 varied greatly between the paracentral measurements in KC., Conclusion: Centration and measurement zone diameter have great impacts on the astigmatic values in KC. A small pupil-centred measurement zone should be considered when evaluating the astigmatism in KC., (© 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background/aim: To describe the intereye asymmetry in patients with keratoconus (KC), keratoconus suspect (KCS) and normal participants, and to evaluate the relationship between asymmetry and disease severity., Methods: In this prospective observational comparative study, 446 patients with bilateral KC, 68 patients with bilateral KCS and 306 normal participants underwent topographic, keratometric and pachymetric evaluations by Pentacam as well as refractive and visual acuity examinations. The intereye asymmetry in each parameter was calculated and compared between the groups., Results: All parameters were significantly different between the worse and better eyes in the KC group (p<0.05), but not in the KCS and normal groups. No significant differences were observed in the measurements of the worse and better eyes of the normal group (p>0.05). There was a statistically significant greater intereye asymmetry in all parameters in the KC group compared with the KCS and normal groups (p<0.05). The intraclass correlations were poor in patients with KC, moderate to good in patients suspected with KC and strong in normal participants. There were statistically significant relationships between the intereye asymmetry in all parameters and KC severity in the worse eye in which intereye asymmetry significantly increased with an increase in disease severity, based on Keratoconus Severity Score classification (p<0.05). According to receiver operating characteristic analysis, the intereye asymmetry would effectively discriminate KC and KCS from normal eyes., Conclusion: KC is an asymmetric disease, and the degree of asymmetry is associated with disease severity. The analysis of intereye asymmetry should be performed along with unilateral evaluation in the screening of KC., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: To evaluate the intrasession repeatability of anterior chamber depth (ACD), central (CCT) and peripheral corneal thickness (PCT), white-to-white diameter (WTW), and irido-corneal angle (IA) measurements obtained with a multidiagnostic device in healthy eyes., Methods: A total of 107 eyes of 107 patients ranging in age from 23 to 65 years were examined with the VX120 system (Visionix-Luneau Technologies). Three consecutive measurements were obtained with this device to assess the intrasession repeatability of ACD, CCT, PCT at different nasal and temporal locations, WTW, and nasal and temporal IA. Data analysis included the calculation of within-subject standard deviation (S w ), intrasubject precision (1.96xS w ), coefficient of variation (CV) and intraclass correlation coefficient (ICC)., Results: The S w and CV for ACD was 0.03 mm and 1.16%, respectively, with an ICC of 0.992. The S w values for central and peripheral pachymetric measurements were below 9 μm, with CV of less than 1.6% and ICC of 0.976 or higher. For IA measurements, S w values of 0.84 or lower were found, with a CV between 1 and 2%, and an ICC of more than 0.970. The S w for WTW was 0.24 mm and the CV was 1.95%. No statistically significant correlations were found between any anatomical parameter evaluated and their S w and CV values associated (-0.220 ≤ r ≤ 0.204, p ≥ 0.125)., Conclusions: The VX120 system is able to provide repeatable measurements of anatomical parameters in healthy eyes. Inter-observer repeatability should be evaluated in future studies.

Purpose: To evaluate the intrasession repeatability of refractive and ocular aberrometric measurements obtained using a new multidiagnostic device in healthy eyes., Patients and Methods: A total of 107 eyes of 107 patients, age ranging from 23 to 65 years, were enrolled in this study. A complete eye examination was performed in all eyes, including an ocular examination using the VX120 system. Three consecutive measurements were obtained using this device to assess the intrasession repeatability of different refractive and ocular aber-rometric parameters. The within-subject standard deviation (S w ), intrasubject precision (1.96×S w ), and intraclass correlation coefficient (ICC) were calculated., Results: S w and intrasubject precision for refractive data were below 0.12 and 0.20 D, respectively, in all cases. The ICC ranged from 0.947 for the J 45 power vector component to 0.997 for the sphere. Concerning aberrometric measurements S w and intrasubject precision values were below 0.05 µm and 0.10 µm, respectively. Likewise, the ICC ranged from 0.805 for the quadrafoil root mean square to 0.954 for the primary spherical aberration. Poor correlations were found between most of the refractive parameters and their S w (-0.033≤ r ≤0.053, p ≥0.064). Moderate and significant positive correlations were found between the magnitude of the aberrometric parameters evaluated and their S w ( r ≥0.446, p <0.001)., Conclusion: The new multidiagnostic device evaluated is able to provide consistent measurements of refraction and ocular aberrations in healthy eyes. Future studies should confirm if this consistency is also observed in highly aberrated eyes., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Background/aims: Obesity is believed to accelerate age-related cataractogenesis through various biomechanisms. On the contrary, there are also studies advocating the protective role of obesity against the cataract formation process. We investigate the correlation of body mass index (BMI) as a measure for obesity with crystalline optical lens density and opacity in a healthy adult population., Methods: In a cross-sectional setting, 93 consecutive disease-free adult individuals who were working staff of a university-based hospital were assessed for the association between crystalline lens density and opalescence [measured by the objective Pentacam HR lens densitometry and subjective Lens Opacity Classification System III (LOCS III), respectively] with the degree of obesity as defined by BMI., Results: LOCS III and crystalline lens density readings were positively correlated [Spearman rho CC ( p value) = 0.224 (0.034)]. However, we found neither LOCS III nor crystalline lens density to be correlated with BMI [Spearman rho CC = -0.008 ( p = 0.943) and -0.062 ( p = 0.560), respectively]., Conclusions: Results from the present study indicate a lack of association between obesity and densitometry of the crystalline in the adult population group. Further studies are required to confirm the order of causality and pathogenesis of this finding., (Copyright © 2017 by S. Karger AG, Basel.)

Purpose: To analyze single session, intrauser reliability of a Scheimpflug device for anterior chamber (AC) and corneal parameters., Methods: In this observational study, 100 normal candidates underwent Scheimpflug analysis with Sirius 3D Rotating Scheimpflug Camera and Topography System (Costruzione Strumenti Oftalmici, Italy). Two scans in dark room conditions were performed by the same experienced user. The candidates were asked to keep both eyes closed for 5min before the scans. Exclusion criteria were previous ocular surgery, corneal scarring and anterior segment/posterior segment anomalies. Only the right eyes were used for the analysis. Both corneal (central, minimum, and apical thickness, volume, horizontal visible iris diameter, and apical curvature) and anterior chamber (volume, depth, angle, horizontal diameter) measurements were evaluated., Results: There was no difference in the means of repeated measurements (p>0.05, ANOVA). Intraclass correlations between the measures were high and ranged from 0.995-0.997 for corneal to 0.964-0.997 for anterior chamber (AC) parameters. The precision of repeatability measures (1.96×Sw) was approximately 5μ for the central and minimum corneal thickness, 8μ for the apical corneal thickness, 0.06mm for AC (anterior chamber) depth and less than 2° for the AC angle., Conclusions: Sirius Scheimpflug system has high repeatability for both corneal and AC parameters in normal eyes., (Copyright © 2015 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.)

To diagnose keratoconus at its earliest stage is meaningful in order to avoid refractive surgery in the eye, which may lead to further damage in the abnormal cornea structure and consequently cause iatrogenic ectasia. In this article, the following aspects of detecting earliest stage of keratoconus were reviewed: 1) nomenclature of the earliest forms of keratoconus; 2) diagnosis of keratoconus using curvature-based topography (also known as Placido-based topography, ie, videokeratography) as a traditional method and elevation-based topography as a new method which has gained popularity in recent years; and 3) other methods analyzing keratoconus cornea like corneal biomechanics and wavefront sensing. Elevation-based topography using either Scheimpflug imaging techniques or slit-scanning imaging techniques has shown to be advantageous over the curvature-based topography in detecting keratoconus at its earliest stage. Posterior elevation of the cornea is notified to enhance the sensitivity and specificity of detection if used along with the measurements of anterior surface of the cornea. Cornea biomechanics analysis and wavefront sensing also revealed differences between normal eyes and keratoconic eyes in their earliest stage. Combining the latest technology and the traditional techniques will be the future trend to improve early diagnosis of keratoconus., Competing Interests: Disclosure The author reports no conflicts of interest in this work.

This case report aims to evaluate safety, efficacy and feasibility of anterior surface imaging by a novel point-source reflection topographer, in comparison to four other corneal imaging modalities. A 17-year-old female patient, clinically diagnosed with chronic herpetic keratitis in her left eye was imaged by a novel multicolored-spot reflection topography system. We comparatively investigated elevation and curvature maps between the novel topographer and established Placido disk topography and Scheimpflug tomography systems. Pachymetry maps were compared between the Scheimpflug system and anterior-segment optical coherence tomography system. The Placido system failed to properly register the abnormal anterior surface due to incomplete mire registration, while the Scheimpflug topometry device imaged the anterior surface properly, but not the posterior (due to media opacity), and thus pachymetry was highly irregular and erroneous in this case. Imaging of corneas infected with herpes simplex virus keratitis has been rare; we have not identified any such documentation in the peer review literature in the last 10 years. This novel multicolored-spot reflection topography imaging may offer successful corneal imaging in cases where established clinical topography systems may fail to produce accurate reconstruction of the corneal shape. This is an important case demonstrating exceptional clinical feasibility in such rare cases offered by a newly introduced technology in ophthalmic imaging.