Pupil size measurements with a multifunctional aberrometer/coherence interferometer/tomographer and two infrared-based pupillometers

PURPOSE

To compare precision of pupil size measurements of a multifunctional device (Pentacam AXL Wave [Pentacam]) and 2 infrared-based pupillometers (PupilX, Colvard) and to compare repeatability of Pentacam and PupilX.

SETTING

Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany.

DESIGN

Prospective, comparative trial.

METHODS

Pupil diameter of healthy eyes was measured with Colvard once and Pentacam without glare (WO) and with glare (WG), PupilX in 0, 1, and 16 lux 3 times each. In a second series, measurements with Pentacam WO and PupilX in 0.06 and 0.12 lux were assessed.

RESULTS

36 eyes of participants aged 21 to 63 years were included. Mean pupil diameter was 6.05 mm with Colvard, 5.79 mm (first series), 5.50 mm (second series) with Pentacam WO, 3.42 mm WG, 7.26 mm PupilX in 0, 4.67 mm 1, 3.66 mm 16, 6.82 mm in 0.06, and 6.39 mm in 0.12 lux. Measurements with Pentacam WO were significantly different to PupilX in 0, 0.06, 0.12, and 1 lux (all P < .001), but not to Colvard ( P = .086). Pupil size measured with Pentacam WG and PupilX in 16 lux was not significantly different ( P = .647). Consecutive measurements with Pentacam WO and WG had mean SD of 0.23 mm and 0.20 mm, respectively, and with PupilX 0.11 in 0, 0.24 mm 1, and 0.20 mm in 16 lux.

CONCLUSIONS

Pentacam provided good assessment of pupil size but was not equivalent to PupilX in low lighting conditions. Repeatability was more favorable for Pentacam.

Handheld chromatic pupillometry can reliably detect functional glaucomatous damage in eyes with high myopia

BACKGROUND/AIMS

To assess pupillary light responses (PLRs) in eyes with high myopia (HM) and evaluate the ability of handheld chromatic pupillometry (HCP) to identify glaucomatous functional loss in eyes with HM.

METHODS

This prospective, cross-sectional study included 28 emmetropes (EM), 24 high myopes without glaucoma (HM) and 17 high myopes with confirmed glaucoma (HMG), recruited at the Singapore National Eye Center. Monocular PLRs were evaluated using a custom-built handheld pupillometer that recorded changes in horizontal pupil radius in response to 9 s of exponentially increasing blue (469.1 nm) and red (640.1 nm) lights. Fifteen pupillometric features were compared between groups. A logistic regression model (LRM) was used to distinguish HMG eyes from non-glaucomatous eyes (EM and HM).

RESULTS

All pupillometric features were similar between EM and HM groups. Phasic constriction to blue (p<0.001) and red (p=0.006) lights, and maximum constriction to blue light (p<0.001) were reduced in HMG compared with EM and HM. Pupillometric features of melanopsin function (postillumination pupillary response, PIPR area under the curve (AUC) 0-12 s (p<0.001) and PIPR 6 s (p=0.01) to blue light) were reduced in HMG. Using only three pupillometric features, the LRM could classify glaucomatous from non-glaucomatous eyes with an AUC of 0.89 (95% CI 0.77 to 1.00), sensitivity 94.1% (95% CI 82.4% to 100.0%) and specificity 78.8% (95% CI 67.3% to 90.4%).

CONCLUSION

PLRs to ramping-up light stimuli are unaltered in highly myopic eyes without other diagnosed ocular conditions. Conversely, HCP can distinguish glaucomatous functional loss in eyes with HM and can be a useful tool to detect/confirm the presence of glaucoma in patients with HM.

One-field, two-field and five-field handheld retinal imaging compared with standard seven-field Early Treatment Diabetic Retinopathy Study photography for diabetic retinopathy screening

BACKGROUND/AIMS

To determine agreement of one-field (1F, macula-centred), two-field (2F, disc-macula) and five-field (5F, macula, disc, superior, inferior and nasal) mydriatic handheld retinal imaging protocols for the assessment of diabetic retinopathy (DR) as compared with standard seven-field Early Treatment Diabetic Retinopathy Study (ETDRS) photography.

METHODS

Prospective, comparative instrument validation study. Mydriatic retinal images were taken using three handheld retinal cameras: Aurora (AU; 50° field of view (FOV), 5F), Smartscope (SS; 40° FOV, 5F), and RetinaVue (RV; 60° FOV, 2F) followed by ETDRS photography. Images were evaluated at a centralised reading centre using the international DR classification. Each field protocol (1F, 2F and 5F) was graded independently by masked graders. Weighted kappa (Kw) statistics assessed agreement for DR. Sensitivity (SN) and specificity (SP) for referable diabetic retinopathy (refDR; moderate non-proliferative diabetic retinopathy (NPDR) or worse, or ungradable images) were calculated.

RESULTS

Images from 225 eyes of 116 patients with diabetes were evaluated. Severity by ETDRS photography: no DR, 33.3%; mild NPDR, 20.4%; moderate, 14.2%; severe, 11.6%; proliferative, 20.4%. Ungradable rate for DR: ETDRS, 0%; AU: 1F 2.23%, 2F 1.79%, 5F 0%; SS: 1F 7.6%, 2F 4.0%, 5F 3.6%; RV: 1F 6.7%, 2F 5.8%. Agreement rates of DR grading between handheld retinal imaging and ETDRS photography were (Kw, SN/SP refDR) AU: 1F 0.54, 0.72/0.92; 2F 0.59, 0.74/0.92; 5F 0.75, 0.86/0.97; SS: 1F 0.51, 0.72/0.92; 2F 0.60, 0.75/0.92; 5F 0.73, 0.88/0.92; RV: 1F 0.77, 0.91/0.95; 2F 0.75, 0.87/0.95.

CONCLUSION

When using handheld devices, the addition of peripheral fields decreased the ungradable rate and increased SN and SP for refDR. These data suggest the benefit of additional peripheral fields in DR screening programmes that use handheld retinal imaging.

New disposable esthesiometer (KeraSenseⓇ) to improve diagnosis and management of neurotrophic keratitis

PURPOSE

To validate the use, repeatability, and reproducibility of a new, cost-effective, disposable, sterile device (KeraSenseⓇ, Dompè farmaceutici SpA, Milan Italy) compared to Cochet-Bonnet (CB) esthesiometer. Secondly, to identify a simple, safe, rapid, and low-cost test to diagnose neurotrophic keratitis (NK).

METHODS

16 patients with diagnosis of NK stage I, 25 patients with diabetes mellitus (DM), and 26 healthy subjects were included in the study. Corneal sensitivity (CS) was assessed by CB and KeraSenseⓇ. Repeatability, accuracy, and reproducibility of the novel disposable aesthesiometer were assessed. Specificity, sensitivity, and cut-off value for NK diagnosis were calculated by ROC curve analysis.

RESULTS

All NK patients showed a CS ≤ 40 mm, while none of the healthy patients showed a CS value < 50 mm. Significant agreement was found between CB measurements and the single use esthesiometer evaluations of CS (p < 0.001). Repeatability evaluations of the single use esthesiometer showed 100% agreement between different measurements (p < 0.001). Reproducibility evaluations showed 99.6% concordance between different operators (p < 0.001). A 55 mm value of the single use esthesiometer was adequate to exclude an NK diagnosis, while all NK patients showed a value ≤ 35 mm.

CONCLUSIONS

Corneal hypo/anaesthesia is considered the hallmark of NK. The use of the novel single-use esthesiometer will allow for a diagnostic improvement in NK, sparing time and guaranteeing patients' safety. Diabetic patients despite normal corneal findings may show impairment of CS, suggesting a preclinical stage of NK, requiring a close follow-up.

Bulbar Redness and Dry Eye Disease: Comparison of a Validated Subjective Grading Scale and an Objective Automated Method

SIGNIFICANCE

In this study, assessments of conjunctival redness were performed to evaluate whether patients with or without dry eye disease (DED) could be discriminated based on this measure. Our findings suggest that subjectively grading redness by quadrant, as opposed to automated en face measurements, may be more suitable for this purpose.

PURPOSE

This study aimed to quantify bulbar redness using the validated bulbar redness (VBR) grading scale and an automated objective method (Oculus Keratograph 5M; K5M) in participants with DED and non-DED controls.

METHODS

Participants with DED (Ocular Surface Disease Index score ≥20 and Oxford scale corneal staining ≥2) and controls (Ocular Surface Disease Index score ≤10 and corneal staining ≤1) attended two study visits. In part 1A of visit 1, baseline bulbar redness was graded with the VBR scale in each conjunctival quadrant of both eyes, followed by automated measurements of temporal and nasal redness with the K5M. This was immediately followed by part 1B, during which a topical vasoconstrictor was instilled into both eyes. Redness assessments were repeated 5 and 30 minutes after instillation with both instruments. Participants returned 14 days later for visit 2, where the same assessments as for visit 1A were repeated.

RESULTS

Seventy-four participants (50 DED and 24 controls) completed the study. There were statistically significant differences in redness between the DED and control groups when assessed with the VBR scale (14/16 comparisons; all, P < .05), whereas no significant differences in K5M-derived redness between the DED and non-DED groups were found at any location or time point. Both subjective and objective instruments detected statistically significant reductions in redness 5 and 30 minutes after instillation of the vasoconstrictor (all, P < .01).

CONCLUSIONS

Although both subjective and objective instruments were sensitive to detecting changes in redness induced by vasoconstriction, statistically significant differences in redness between DED and control groups were only found using the VBR scale.

Image quality and diagnostic accuracy of a handheld nonmydriatic fundus camera: Feasibility of a telemedical approach in screening retinal diseases

BACKGROUND

A suitable fundus camera for telemedicine screening can expand the scale of eye care service. The purpose of this study was to compare a handheld nonmydriatic digital fundus camera and a conventional mydriatic fundus camera according to the image quality of their photographs and usability of those photographs to accurately diagnose various retinal diseases.

METHODS

A handheld nonmydriatic fundus camera and conventional fundus camera were used to take fundus photographs of outpatients at an ophthalmic clinic before and after pupillary dilation. Image quality and diagnostic agreement of the photos were graded by two masked and experienced retinal specialists.

RESULTS

A total of 867 photographs of 393 eyes of 200 patients were collected. Approximately 80% of photos taken under nonmydriasis status using the handheld nonmydriatic fundus camera had good (55.7%) or excellent (22.7%) image quality. The overall agreement of diagnoses between the doctors was more than 90%. When the handheld nonmydriatic fundus camera was used after mydriasis, the proportion of images with good (45%) or excellent (49.7%) quality reached 94.7% and diagnostic agreement was 93.4%. Lens opacity was associated with the quality of images obtained using the handheld camera (p = 0.041), and diagnosis disagreement for handheld camera images was associated with preexisting diabetes diagnosis (p = 0.009). Approximately 40% of patients expressed preference for use of the handheld nonmydriatic camera.

CONCLUSION

This study demonstrated the effectiveness of the handheld nonmydriatic fundus camera in clinical practice and its feasibility for telemedicine screening of retinal diseases.

Smartphone-Based Fundus Imaging-Where Are We Now?

With the advent of smartphone-based fundus imaging (SBFI), a low-cost alternative to conventional digital fundus photography has become available. SBFI allows for a mobile fundus examination, is applicable both with and without pupil dilation, comes with built-in connectivity and post-processing capabilities, and is relatively easy to master. Furthermore, it is delegable to paramedical staff/technicians and, hence, suitable for telemedicine. Against this background a variety of SBFI applications have become available including screening for diabetic retinopathy, glaucoma, and retinopathy of prematurity and its applications in emergency medicine and pediatrics. In addition, SBFI is convenient for teaching purposes and might serve as a surrogate for direct ophthalmoscopy. First wide-field montage techniques are available and the combination of SBFI with machine learning algorithms for image analyses is promising. In conclusion, SBFI has the potential to make fundus examinations and screenings for patients particularly in low- and middle-income settings more accessible and, therefore, aid tackling the burden of diabetic retinopathy, glaucoma, and retinopathy of prematurity screening. However, image quality for SBFI varies substantially and a reference standard for grading appears prudent. In addition, there is a strong need for comparison of different SBFI approaches in terms of applicability to disease screening and cost-effectiveness.

Optical coherence tomography (OCT) in unconscious and systemically unwell patients using a mobile OCT device: a pilot study

OBJECTIVE

This study aims to evaluate the feasibility of retinal imaging in critical care using a novel mobile optical coherence tomography (OCT) device. The Heidelberg SPECTRALIS FLEX module (Heidelberg Engineering, Heidelberg, Germany) is an OCT unit with a boom arm, enabling ocular OCT assessment in less mobile patients.

DESIGN

We undertook an evaluation of the feasibility of using the SPECTRALIS FLEX for undertaking ocular OCT images in unconscious and critically ill patients.

SETTING

This study was conducted in the critical care unit of a large tertiary referral unit in the United Kingdom.

PARTICIPANTS

13 systemically unwell patients admitted to the critical care unit were purposively sampled to enable evaluation in patients with a range of clinical states.

OUTCOME MEASURES

The primary outcome was the feasibility of acquiring clinically interpretable OCT scans on a consecutive series of patients. The standardised scanning protocol included macula-focused OCT, OCT optic nerve head (ONH), OCT angiography (OCTA) of the macula and ONH OCTA.

RESULTS

OCT images from 13 patients were attempted. The success rates of each scan type are 84% for OCT macula, 76% for OCT ONH, 56% for OCTA macula and 36% for OCTA ONH. The overall mean success rate of scans per patient was 64% (95% CI 46% to 81%). Clinicians reported clinical value in 100% scans which were successfully obtained, including both ruling in and ruling out relevant ocular complications such as corneal thinning, macular oedema and optic disc swelling. The most common causes of failure to achieve clinically interpretable scans were inadequately sustained OCT alignment in delirious patients and a compromised ocular surface due to corneal exposure.

CONCLUSIONS

This prospective evaluation indicates the feasibility and potential clinical value of the SPECTRALIS FLEX OCT system on the critical care unit. Portable OCT systems have the potential to bring instrument-based ophthalmic assessment to critically ill patients, enabling detection and micron-level monitoring of ocular complications.

Agreement between Pentacam and handheld Auto-Refractor/Keratometer for keratometry measurement

OBJECTIVE

This study was conducted to evaluate the level of agreement in keratometry measurements between a rotating Scheimpflug imaging-based system (Pentacam) and a handheld auto-refractokeratometer (handheld NIDEK ARK-30).

METHOD

This analytical cross-sectional study was conducted in the right eyes of 579 subjects. Keratometry measurements were conducted with the Pentacam and the handheld NIDEK ARK-30 systems. The SPSS Software version 22 and MedCalc V3 were applied to estimate descriptive statistics using paired t-test, Pearson correlation coefficient, 95% limits of agreement (LoA), and Bland-Altman plot.

RESULTS

In the total sample, the inter-device difference in the mean flat and steep keratometry values was -0.266 diopter (D) (P-value<0.001) and 0.052D (P-value=0.093), respectively. There was a significant difference in mean flat keratometry between the two devices in all groups of refractive errors (paired difference <0.5D and P-value<0.001). The difference in mean steep keratometry was significant only in myopic subjects (P-value=0.046). The 95% LoA between the two devices measurements was 2.51D, 3.98D, and 6.37D for flat keratometry and 2.6D, 3.2D, and 3.9D for steep keratometry in emmetropic, myopic, and hyperopic subjects, respectively.

CONCLUSION

Our study showed relatively wide limits of agreement between handheld NIDEK ARK-30 and Pentacam; therefore, these devices cannot be used interchangeably for measuring corneal curvature.

Keratometry in children: Comparison between auto-refractokeratometer, rotating scheimpflug imaging, and biograph

PURPOSE

To determine the agreement and validity of keratometric measurements in children with the Nidek ARK-510A auto-refractokeratometer compared to rotating Scheimpflug imaging with Pentacam and biograph with Lenstar LS 900.

METHODS

This study was conducted on 5620 schoolchildren aged 6-12 years in Shahroud, Iran. Minimum and maximum keratometry values and corneal astigmatism magnitude were compared by calculation of Paired difference, interclass correlation coefficient, and 95% limits of agreement (LoA) between devices.

RESULTS

After applying the exclusion criteria, 4215 right eyes were enrolled into the study. Mean minimum keratometry with Nidek ARK-510A, Pentacam, and Lenstar was 43.13±1.51, 43.14±1.48, and 42.87±1.46 diopters (D), respectively, and mean maximum keratometry was 43.97±1.59, 44.00±1.56, and 43.75±1.54D, respectively. Nidek ARK-510A overestimated minimum and maximum keratometry by 0.25±0.37 and 0.22±0.41, respectively, compared to Penatcam. The LoA between Nidek ARK-510A and Pentacam for minimum and maximum keratometry measurements were -0.98 to 0.47D and -1.02 to 0.57D, respectively. The LoA between Nidek ARK-510A and Lenstar for minimum and maximum keratometry measurements were -0.70 to 0.72D and -0.79 to 0.85D, respectively. The agreement between devices was best in emmetropes, worst in hyperopes. For astigmatic vector components, the agreements between devices were poor but best agreement was between Nidek ARK-510A and Pentacam.

CONCLUSIONS

Keratometry measurement with Nidek ARK-510A was not significantly different from Pentacam and Lenstar, and this device can be used in screening programs in emmetropes.

An Approach to Automatic Hard Exudate Detection in Retina Color Images by a Telemedicine System Based on the d-Eye Sensor and Image Processing Algorithms

Hard exudates are one of the most characteristic and dangerous signs of diabetic retinopathy. They can be marked during the routine ophthalmological examination and seen in color fundus photographs (i.e., using a fundus camera). The purpose of this paper is to introduce an algorithm that can extract pathological changes (i.e., hard exudates) in diabetic retinopathy. This was a retrospective, nonrandomized study. A total of 100 photos were included in the analysis—50 sick and 50 normal eyes. Small lesions in diabetic retinopathy could be automatically diagnosed by the system with an accuracy of 98%. During the experiments, the authors used classical image processing methods such as binarization or median filtration, and data was read from the d-Eye sensor. Sixty-seven patients (39 females and 28 males with ages ranging between 50 and 64) were examined. The results have shown that the proposed solution accuracy level equals 98%. Moreover, the algorithm returns correct classification decisions for high quality images and low quality samples. Furthermore, we consider taking retina photos using mobile phones rather than fundus cameras, which is more practical. The paper presents an innovative approach. The results are introduced and the algorithm is described.

Evaluating changes of blood flow in retina, choroid, and outer choroid in rats in response to elevated intraocular pressure by 1300 nm swept-source OCT

We report the development of a 1300 nm swept-source optical coherence tomography (SS-OCT) system specifically designed to perform OCT imaging and optical microangiography (OMAG) in rat eyes in vivo and its use in evaluating the effects of intraocular pressure (IOP) elevation on ocular circulation. The swept laser is operated in single longitude mode with a 90 nm bandwidth centered at 1300 nm and 200 kHz A-line rate, providing remarkable sensitivity fall-off performance along the imaging depth, a larger field of view of 2.5 × 2.5 mm2 (approximately 35°), and more time-efficient imaging acquisition. The advantage of the SS-OCT/OMAG is highlighted by an increased imaging depth of the entire posterior thickness of optic nerve head (ONH) and its surrounding vascular anatomy, to include, for the first time in vivo, the vasculature at the scleral opening, allowing visualization of the circle of Zinn-Haller and posterior ciliary arteries (PCAs). Furthermore, the capillary-level resolution angiograms achieved at the retinal and choroidal layers over a larger field of view enable a significantly improved quantification of the response of vascular area density (VAD) to elevated IOP. The results indicate that reduction in perfusion of the choroid in response to elevated IOP is delayed compared to that seen in the retina; while choroidal VAD doesn't reach 50% of baseline until ~70 mmHg, the same effect is seen for the retinal VAD at ~60 mmHg. The superior image quality offered by SS-OCT may allow more comprehensive investigation of IOP-related ocular perfusion changes and their pathological roles in glaucomatous optic nerve damage.

Agreement of post-LASIK corneal power and corneal thickness measurements by pentacam and GALILEI corneal tomography systems

BACKGROUND

Post-LASIK corneal conditions cannot be accurately measured by traditional optometric approaches. Therefore, we aimed to analyze the agreement of two rotating Scheimpflug cameras in corneal assessment.

METHODS

Fifty otherwise healthy volunteers who had undergone LASIK were recruited in this study. The values of mean and central total corneal power (TCP), including TCP1, TCP2, and TCP-IOL, were measured by GALILEI Scheimpflug camera. The values of total corneal refractive power (TCRP) readings at both 2 mm ring and 3 and 4 mm zones were detected by Pentacam Scheimpflug camera. Central corneal thickness (CCT) and thinnest corneal thickness (TCT) were quantified by GALILEI and Pentacam respectively. Paired t-tests and Bland-Altman analyses were used to evaluate statistical differences between measurement results obtained by GALILEI and by Pentacam.

RESULTS

Among these 50 subjects, the mean and central TCP1 values (37.31 ± 2.61 and 37.27 ± 2.64) derived from GALILEI measurements were consistent with the TCRP values (37.08 ± 2.76, 37.11 ± 2.74, and 37.19 ± 2.68; p > 0.05) determined by Pentacam at the 2 mm ring apex, 3 mm zone apex, and 4 mm zone apex. There were no statistically significant differences in central corneal thickness (CCT) values measured by the two cameras (463.64 ± 55.67 μm for GALILEI and 470.69 ± 44.04 μm for Pentacam, respectively; p > 0.05). However, the limits of agreement were wide when comparing mean TCP1 (-1.4 to 1.8 D, -1.4 to 1.8 D, and -1.3 to 1.6 D), central TCP1 (-1.2 to 1.6 D, -1.2 to 1.6 D, and -1.2 to 1.4 D) and CCT (-77.2-63.0 μm).

CONCLUSION

Corneal power and corneal thickness are disparate post-LASIK evaluation parameters when comparing the utility of GALILEI with that of Pentacam.

Corneal biomechanical properties in patients with Hashimoto's thyroiditis

BACKGROUND

Hashimoto's thyroiditis (HT) is an autoimmune endocrine disorder that results from a dysregulation of the immune system leading to an immune attack on the thyroid gland. It has potential effects on different organs and tissues.

OBJECTIVES

The aim of the study was to investigate the effect of HT on corneal biomechanical properties using the ocular response analyzer (ORA).

MATERIAL AND METHODS

A total of 48 patients with HT and 49 healthy subjects were enrolled in the study. The mean age of the patients and healthy subjects was 42.33 ±11.96 and 40.20 ±12.60 years, respectively (p = 0.39). All of the subjects underwent a full ophthalmological examination, including visual acuity, corneal pachymetry with topography, biomicroscopy, and funduscopy. Corneal biomechanical properties, including corneal hysteresis (CH) and corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg) and corneal compensated IOP (IOPcc) were measured with the ORA.

RESULTS

Central corneal thickness (CCT) in the patient group and the control group were not significantly different (p = 0.65). Corneal hysteresis of the HT patients was significantly lower than that of the control group (p = 0.005). There were no statistically significant differences in CRF between the 2 groups (p = 0.53). Goldmann-correlated IOP and IOPcc were higher in the HT patients, but only IOPcc showed a statistically significant difference (p = 0.001).

CONCLUSIONS

In conclusion, our data shows that HT affects corneal biomechanical properties by decreasing CH. Thus, IOPcc measured with the ORA should be taken into account when determining accurate IOP values in patients with HT.

Intraocular pressure remote photonic biomonitoring based on temporally encoded external sound wave stimulation

Continuous noninvasive measurement of intraocular pressure (IOP) is an important tool in the evaluation process for glaucoma. We present a methodology enabling high-precision, noncontact, reproducible, and continuous monitoring of IOP based on the value of the damping factor of transitional oscillations obtained at the surface of the eye after terminating its stimulation by a sound wave. The proposed configuration includes projection of a laser beam and usage of a fast camera for analyzing the temporal-spatial variations of the speckle patterns backscattered from the iris or the sclera following the above-mentioned sound waves external stimulation. The methodology was tested on an artificial eye and a carp fish eye under varying pressure as well as on human eyes.

Validity and Reliability of a Novel Handheld Osmolarity System for Measurement of a National Institute of Standards Traceable Solution

PURPOSE

To evaluate the validity and reliability of a novel handheld osmolarity system (I-PEN Osmolarity System; I-MED Pharma Inc, Dollard-des-Ormeaux, Quebec, Canada) for measurement of the osmolarity of a National Institute of Standards and Technology (NIST) traceable solution at a variety of ambient temperatures.

METHODS

A total of 65 measurements of an NIST solution with a verified osmolarity of 290 ± 2 mOsmol/L were taken using 3 separate handheld osmolarity systems, 65 unique single-use sensors (SUSs) from 3 different lots, and 2 adaptors. Mean values were calculated using the device, SUS, and adaptor. Measurements were taken using a handheld osmolarity system, an adaptor, and 56 individual SUSs at 6 different ambient temperatures ranging from 17.7 to 26.5°C.

RESULTS

Overall, the mean osmolarity measured was 294.06 mOsmol/L (SD ±2.29; percent coefficient of variation 0.78), ranging from 286.60 to 298.18 mOsmol/L. This fell within a prespecified acceptable variability of ±4 mOsmol/L (SD ±7). Mean values did not vary across devices, adaptors, or single-use sensors used. Mean osmolarity measurements increased with rising ambient temperatures, with an R = 0.88. The temperature correction factor was calculated to be 2.01 mOsmol/L per °C.

CONCLUSIONS

The osmolarity system reliably and accurately measured the osmolarity of an NIST solution in a laboratory setting, using an adaptor to correct for differences in resistance between a laboratory NIST solution measurement and direct measurements on the palpebral conjunctiva of the eyelid. The handheld osmolarity system represents a rapid and accurate instrument for measurement of tear osmolarity in a simulated testing setting.

Preoperative Prediction of the Optimal Toric Intraocular Lens Alignment Meridian

PURPOSE

To determine whether any of three keratometry devices is superior to the others in predicting the ideal toric intraocular lens (IOL) alignment meridian.

METHODS

A retrospective review was performed to identify patients who underwent cataract phacoemulsification with toric IOL implantation from November 2014 to November 2016 at a single academic institution. For each patient, corneal measurements were performed with an optical low-coherence reflectometer/autokeratometer (OLCR), a dual Scheimpflug/Placido analyzer, and a color light-emitting diode (LED) topographer. Postoperatively, the ideal toric IOL alignment meridian that would have resulted in the least amount of residual astigmatism was determined using the online Berdhal & Hardten Toric Results Analyzer (BHTRA). To determine the prediction error, this ideal alignment meridian was compared to the corneal meridian with the highest refractive power, as provided by the three devices.

RESULTS

Fifty-six eyes of 56 patients were included in the study. The mean absolute errors in the toric IOL alignment meridians of the color LED topographer, dual Scheimpflug/Placido analyzer, and OLCR were 5.2° ± 5.2°, 7.6° ± 5.7°, and 5.4° ± 5.1°, respectively. There was no significant difference in the ability of each device to predict the ideal alignment meridian as determined by the BHTRA.

CONCLUSIONS

The color LED topographer, dual Scheimpflug/Placido analyzer, and OLCR may all be used to preoperatively determine the best alignment meridian for toric IOL placement. Surgeons should use their best judgment in determining which device to use in preoperative planning for individual patients. [J Refract Surg. 2018;34(8):515-520.].

Corneal Biomechanics After Accelerated Cross-linking: Comparison Between 18 and 9 mW/cm2 Protocols

PURPOSE

To determine 1-year corneal biomechanical changes after accelerated corneal cross-linking in patients with progressive keratoconus and compare them between 5-minute (18 mW/cm²) and 10-minute (9 mW/cm²) protocols.

METHODS

In this non-randomized clinical trial, cases in both groups were examined with the Corneal Visualization Scheimpflug Technology (Corvis ST; Oculus Optikgeräte GmbH, Wetzlar, Germany) at baseline and at 6 and 12 months after treatment. Extracted indices included intraocular pressure (IOP), central corneal thickness (CCT), first and second applanation times, lengths, and velocities (T1, T2, L1, L2, V1, and V2), highest concavity time (HCT), deformation amplitude (DA), peak distance between bending points, and radius of curvature.

RESULTS

Mean patient age, baseline maximum keratometry, CCT, and IOP were similar between groups. After adjusting for CCT and baseline values with repeated measures analysis of covariance, at 1 year after the procedure, IOP (13.14 ± 1.41 vs 12.12 ± 1.49 mm Hg, P = .034) and T1 (6.84 ± 0.20 vs 6.67 ± 0.23 ms, P = .036) were higher in the 5-minute group, but T2 (21.31 ± 0.27 vs 21.58 ± 0.28 ms, P = .007), HCT (16.06 ± 0.51 vs 16.31 ± 0.48 ms, P = .017), and DA (1.03 ± 0.09 vs 1.10 ± 0.08 mm, P = .028) were lower. Other inter-group differences were not statistically significant (all P > .050). All 1-year changes were independent of cone position (all P > .050).

CONCLUSIONS

At 1 year after cross-linking in cases of mild and moderate keratoconus, corneal biomechanics appeared stable or stronger than baseline with both 5- and 10-minute protocols. However, mild cases who had the 5-minute protocol showed better improvement based on Corvis ST indices. [J Refract Surg. 2017;33(8):558-562.].

Agreement between total corneal astigmatism calculated by vector summation and total corneal astigmatism measured by ray tracing using Galilei double Scheimpflug analyzer

PURPOSE

To evaluate the agreement between total corneal astigmatism calculated by vector summation of anterior and posterior corneal astigmatism (TCA_Vec) and total corneal astigmatism measured by ray tracing (TCA_Ray).

METHODS

This study enrolled a total of 204 right eyes of 204 normal subjects. The eyes were measured using a Galilei double Scheimpflug analyzer. The measured parameters included simulated keratometric astigmatism using the keratometric index, anterior corneal astigmatism using the corneal refractive index, posterior corneal astigmatism, and TCA_Ray. TCA_Vec was derived by vector summation of the astigmatism on the anterior and posterior corneal surfaces. The magnitudes and axes of TCA_Vec and TCA_Ray were compared. The Pearson correlation coefficient and Bland-Altman plots were used to assess the relationship and agreement between TCA_Vec and TCA_Ray, respectively.

RESULTS

The mean TCA_Vec and TCA_Ray magnitudes were 0.76±0.57D and 1.00±0.78D, respectively (P<0.001). The mean axis orientations were 85.12±30.26° and 89.67±36.76°, respectively (P=0.02). Strong correlations were found between the TCA_Vec and TCA_Ray magnitudes (r=0.96, P<0.001). Moderate associations were observed between the TCA_Vec and TCA_Ray axes (r=0.75, P<0.001). Bland-Altman plots produced the 95% limits of agreement for the TCA_Vec and TCA_Ray magnitudes from -0.33 to 0.82D. The 95% limits of agreement between the TCA_Vec and TCA_Ray axes was -43.0 to 52.1°.

CONCLUSION

The magnitudes and axes of astigmatisms measured by the vector summation and ray tracing methods cannot be used interchangeably. There was a systematic error between the TCA_Vec and TCA_Ray magnitudes.

Precision (repeatability and reproducibility) of ocular parameters obtained by the Tomey OA-2000 biometer compared to the IOLMaster in healthy eyes

Purpose

To assess the precision (repeatability and reproducibility) of ocular parameters measured by the Tomey OA-2000 biometer, and to compare them with those measured by the IOLMaster.

Methods

In this prospective study, the right eyes of 108 healthy subjects were included. Three consecutive scans were obtained by 2 observers using the Tomey OA-2000, and in the same session one observer used the IOLMaster (version 5.4.4.0006) for the measurements. About 1 week later, 3 scans were obtained by one observer using the Tomey OA-2000. The axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), keratometer readings, pupil diameter (PD) and corneal diameter (CD) values measured by the Tomey OA-2000 and IOLMaster were analyzed. The coefficient of variation (CoV), intraclass correlation coefficient (ICC), within subject standard deviation (Sw) and 2.77Sw were calculated to assess the repeatability and reproducibility. The paired t test and Bland-Altman plots were used to analyze the differences and agreements of parameters measured by the two devices, respectively.

Results

Intraobserver repeatability, and interobserver and intersession reproducibility of the AL, CCT, ACD, LT, Kf, Ks, Km, PD and CD values measured by the Tomey OA-2000 biometer showed a CoV of less than 1% except that for PD, and an ICC of more than 0.97 except that for PD and CD. The AL, Kf, Ks, Km and CD values measured by the Tomey OA-2000 were 0.058 ± 0.094 mm, 0.088± 0.150 diopters (D), 0.163 ± 0.170 D, 0.127 ± 0.117 D and 0.171 ± 0.217 mm lower than those measured by the IOLMaster, respectively (all Ps < 0.05). However, the ACD values from the two devices were comparable (P = 0.169). The 95% linite of agreement (LoA) of the AL, ACD, CD and all keratometer readings were no more than 0.24 mm, 0.14 mm 0.60 mm and 0.5 D, respectively.

Conclusion

Except for the PD and CD, the ocular parameters measured by the Tomey OA-2000 were highly repeatable and reproducible. Except for the CD value, there was good agreement of ocular parameters measured by the Tomey OA-2000 and the IOLMaster in healthy eyes.

"The influence of orbital vector on involutional entropion and ectropion"

PURPOSE

This study aimed to evaluate the effect of orbital vector and other biometric parameters (i.e. axial globe length, axial globe projection) on the development of involutional entropion or ectropion.

METHODS

In this cross-sectional study, 167 eyes from 132 patients were included. Of these eyes, 128 had involutional entropion and 39 had involutional ectropion, all of lower lids. The axial globe projection was measured using Hertel exophthalmometry; axial globe length was assessed by A-mode ultrasound; and orbital vector was determined clinically. Patient-specific categorical variables and continuous variables were compared using the chi-square test and the two-sided t test, respectively. Correlations were derived using the Pearson correlation.

RESULTS

The percentage of females was 59% and 33.3% in the entropion group and in the ectropion group, respectively. A significant association was found between the gender and type of eyelid malposition (p = 0.015). Exophthalmometry reading was greater in the ectropion group than in the entropion group (17.7 ± 2.5 versus 10.8 ± 3.7 mm, respectively; p < 0.001). There was no significant correlation between axial globe length and exophthalmometry reading. Positive orbital vectors were observed in 87.5% of eyelids with involutional entropion. Negative orbital vectors were observed in 92.3% of eyelids with involutional ectropion (p < 0.001). Patients with negative orbital vectors showed greater axial globe projection than patients with positive orbital vectors (18.0 ± 2.1 versus 10.6 ± 3.5 mm, respectively; p < 0.001).

CONCLUSIONS

There is an association between orbital vector measurement and involutional entropion and ectropion. Measuring the orbital vector may help predict the development of these lid malpositions.

Pseudoexfoliation signs in the anterior segment assessed by optical coherence tomography and Scheimpflug device

OBJECTIVE

To evaluate different anterior segment parameters in eyes with pseudoexfoliation (PSX), fellow eyes, and controls using optical coherence tomography and a Scheimpflug imaging system.

METHODS

Three groups were studied: 44 eyes of 44 patients with PSX, 30 clinically unaffected fellow eyes, and 148 eyes of 148 healthy controls. The anterior chamber depth and volume, corneal volume and thickness, pupil diameter and corneal densitometry were measured using a Scheimpflug imaging system (Pentacam, Oculus Inc.; Wetzlar, Germany). The angle width, the length and area of the trabecular meshwork, and the iris thickness were measured using an optical coherence tomography RTVue 100 device (Optovue, Fremont, CA, USA). The presence of PSX deposits was also assessed by OCT.

RESULTS

There were no differences in the anterior chamber volume or depth in the corneal volume or central thickness (P≥.228). The corneal densitometry was similar between PSX and fellow eyes; however it was greater than in the control group (P<.001). As regards the parameters measured by OCT, there were no differences in the angle width or in the trabecular meshwork size between the 3 groups; however, the iris was thinner in controls (P=.005). In all patients the PSX deposits were correctly visualised by OCT after the identification by biomicroscopy.

CONCLUSIONS

There were no differences in the anterior segment biometric measurements between patients with PSX and controls, although the corneal densitometry and iris thickness were greater in the PSX and fellow eyes groups.

Relationship of the Van Herick Grading System with Peripheral Iris Configuration and Level of Iris Insertion

OBJECTIVE

To determine the relationship of the van Herick angle grading system with the level of iris insertion and peripheral iris configuration.

STUDY DESIGN

Observational study.

PLACE AND DURATION OF STUDY

Eye department, Combined Military Hospital, Malir Cantt., Karachi, from May to October 2015.

METHODOLOGY

Sixty-five eyes of 65 patients were recruited. Anterior chamber depth at the temporal limbus was measured as a fraction of corneal section thickness using van Herick technique and graded on the standard 4-point scale of the van Herick grading system. Gonioscopy of the temporal quadrant was performed with a Posner 4 mirror goniolens and both the true level of iris insertion and peripheral iris configuration were recorded on a 4-point scale so as to equate with the van Herick 4-point grading system. Spearman's rho test was applied to determine the relationship of the van Herick grading system with level of iris root insertion and peripheral iris configuration.

RESULTS

Amoderate positive correlation between van Herick grade and peripheral iris configuration was found which was statistically significant (rs=0.42, p < 0.001). Astatistically significant and moderate positive correlation was also detected between van Herick grade and the level of iris insertion (rs=0.45, p < 0.001).

CONCLUSION

The van Herick grade has a moderately positive relationship with the peripheral iris configuration and true level of iris insertion.

Corneal Sensitivity as a Potential Marker of Diabetic Neuropathy

Diabetes mellitus (DM) is a complex and chronic metabolic disorder leading to many complications. One of the most common complications of DM is diabetic neuropathy. There are many studies exploring corneal sensitivity as a potential marker of diabetic neuropathy. This review aims to explore association between corneal sensitivity and diabetic neuropathy. In diabetic neuropathy, corneal sensitivity is impaired due to low level of corneal nerve trophic factors, impaired sensory nerve fibers, and lost communication of dendtritic cell. In diabetic patients, this condition can be assessed by several techniques, such as Cochet Bonnet aesthesiometry, non-contact corneal aesthesiometry, and confocal microscopy. Few promising therapeutic targets for impaired corneal sensitivity include stem cell and growth factor therapy that can be used to prevent complication in patient with diabetic neurotrophic keratopathy. Impaired corneal sensitivity serve as a potential marker of diabetic neuropathy. Doctors, opthalmologists and internists, should anticipate the possibility of observing the following changes in diabetic patients with neuropathy by using corneal sensitivity assessment test.

Optical coherence tomography with a 2.8-mm beam diameter and sensorless defocus and astigmatism correction

An optical coherence tomography (OCT) system with a 2.8-mm beam diameter is presented. Sensorless defocus correction can be performed with a Badal optometer and astigmatism correction with a liquid crystal device. OCT B-scans were used in an image-based optimization algorithm for aberration correction. Defocus can be corrected from ? 4.3 ?? D to + 4.3 ?? D and vertical and oblique astigmatism from ? 2.5 ?? D to + 2.5 ?? D . A contrast gain of 6.9 times was measured after aberration correction. In comparison with a 1.3-mm beam diameter OCT system, this concept achieved a 3.7-dB gain in dynamic range on a model retina. Both systems were used to image the retina of a human subject. As the correction of the liquid crystal device can take more than 60 s, the subject’s spectacle prescription was adopted instead. This resulted in a 2.5 times smaller speckle size compared with the standard OCT system. The liquid crystal device for astigmatism correction does not need a high-voltage amplifier and can be operated at 5 V. The correction device is small ( 9 ?? mm × 30 ?? mm × 38 ?? mm ) and can easily be implemented in existing designs for OCT.

Applanation optical coherence elastography: noncontact measurement of intraocular pressure, corneal biomechanical properties, and corneal geometry with a single instrument

Current clinical tools provide critical information about ocular health such as intraocular pressure (IOP). However, they lack the ability to quantify tissue material properties, which are potent markers for ocular tissue health and integrity. We describe a single instrument to measure the eye-globe IOP, quantify corneal biomechanical properties, and measure corneal geometry with a technique termed applanation optical coherence elastography (Appl-OCE). An ultrafast OCT system enabled visualization of corneal dynamics during noncontact applanation tonometry and direct measurement of micro air-pulse induced elastic wave propagation. Our preliminary results show that the proposed Appl-OCE system can be used to quantify IOP, corneal biomechanical properties, and corneal geometry, which builds a solid foundation for a unique device that can provide a more complete picture of ocular health.

Evaluating Silent Reading Performance with an Eye Tracking System in Patients with Glaucoma

Objective

To investigate the relationship between silent reading performance and visual field defects in patients with glaucoma using an eye tracking system.

Methods

Fifty glaucoma patients (Group G; mean age, 52.2 years, standard deviation: 11.4 years) and 20 normal controls (Group N; mean age, 46.9 years; standard deviation: 17.2 years) were included in the study. All participants in Group G had early to advanced glaucomatous visual field defects but better than 20/20 visual acuity in both eyes. Participants silently read Japanese articles written horizontally while the eye tracking system monitored and calculated reading duration per 100 characters, number of fixations per 100 characters, and mean fixation duration, which were compared with mean deviation and visual field index values from Humphrey visual field testing (24–2 and 10–2 Swedish interactive threshold algorithm standard) of the right versus left eye and the better versus worse eye.

Results

There was a statistically significant difference between Groups G and N in mean fixation duration (G, 233.4 msec; N, 215.7 msec; P = 0.010). Within Group G, significant correlations were observed between reading duration and 24–2 right mean deviation (r_s = -0.280, P = 0.049), 24–2 right visual field index (r_s = -0.306, P = 0.030), 24–2 worse visual field index (r_s = -0.304, P = 0.032), and 10–2 worse mean deviation (r_s = -0.326, P = 0.025). Significant correlations were observed between mean fixation duration and 10–2 left mean deviation (r_s = -0.294, P = 0.045) and 10–2 worse mean deviation (r_s = -0.306, P = 0.037), respectively.

Conclusions

The severity of visual field defects may influence some aspects of reading performance. At least concerning silent reading, the visual field of the worse eye is an essential element of smoothness of reading.

[Interobserver and intraobserver reliability of corneal surface temperature measurements with the TG-1000 thermograph in normal eyes]

PURPOSE

The aim of this study was to analyze the reliability of temperature measurements with the ocular TG-1000 thermograph in a setup of sequential measurements performed by one observer (intraobserver) and a sequence of measurements performed by different observers (interobserver) in normal subjects without pathologies of the anterior segment of the eye.

PATIENTS AND METHODS

A total of 50 right eyes from 50 individuals (mean age 29.1 ± 7.9 years) without ocular pathologies or history of ocular surgery were enrolled in this prospective monocentric clinical case series. Eyes with signs of dry eye syndrome (based on a positive McMonnies questionnaire) were excluded from the study. Corneal surface temperature measurements were performed by three examiners to assess interobserver reliability. In addition, in a subgroup of 22 individuals, a sequence of 3 measurements were performed by 1 of the examiners to examine intraobserver reliability. Corneal surface temperature was measured within an interval of 10 s (11 frames) on a region of interest of 16 ± 12 mm (320 ± 240 pixels). Central and mid-peripheral local temperatures at 3 mm (3, 6, 9 and 12 o'clock) were extracted and analyzed from the raw data.

RESULTS

The ocular TG-1000 thermograph yielded consistent results for the interobserver as well as intraobserver conditions in measuring corneal surface temperature in the center as well as mid-periphery of the cornea. Cronbach's alpha was 0.9 or higher at all corneal locations, which proves a high consistency of results for the interobserver and intraobserver measurements. The average corneal surface temperature ranged between 34.0 °C and 34.7 °C with a slight decrease from the upper temporal (9 and 12 o'clock) to the lower nasal (3 and 6 o'clock) quadrants.

CONCLUSION

The TG-1000 thermograph yielded consistent results of corneal surface temperature in individuals without anterior segment pathologies or history of ocular surgery. With the option of raw data export (11 frames within 10 s with a lateral resolution of 320 × 240 pixels) the thermograph offers a wide range of new diagnostic options for a spatiotemporal analysis of corneal surface temperature.

Comparison of Central Corneal Thickness Between Fourier-Domain OCT, Very High-Frequency Digital Ultrasound, and Scheimpflug Imaging Systems

PURPOSE

To compare corneal thickness measurements between three imaging systems.

METHODS

In this retrospective study of 81 virgin and 58 post-laser refractive surgery corneas, central and minimum corneal thickness were measured using optical coherence tomography (OCT), very high-frequency digital ultrasound (VHF digital ultrasound), and a Scheimpflug imaging system. Agreement between methods was analyzed using mean differences (bias) (OCT - VHF digital ultrasound, OCT - Scheimpflug, VHF digital ultrasound - Scheimpflug) and Bland-Altman analysis with 95% limits of agreement (LoA).

RESULTS

Virgin cornea mean central corneal thickness was 508.3 ± 33.2 µm (range: 434 to 588 µm) for OCT, 512.7 ± 32.2 µm (range: 440 to 587 µm) for VHF digital ultrasound, and 530.2 ± 32.6 µm (range: 463 to 612 µm) for Scheimpflug imaging. OCT and VHF digital ultrasound showed the closest agreement with a bias of -4.37 µm, 95% LoA ±12.6 µm. Least agreement was between OCT and Scheimpflug imaging with a bias of -21.9 µm, 95% LoA ±20.7 µm. Bias between VHF digital ultrasound and Scheimpflug imaging was -17.5 µm, 95% LoA ±19.0 µm. In post-laser refractive surgery corneas, mean central corneal thickness was 417.9 ± 47.1 µm (range: 342 to 557 µm) for OCT, 426.3 ± 47.1 µm (range: 363 to 563 µm) for VHF digital ultrasound, and 437.0 ± 48.5 µm (range: 359 to 571 µm) for Scheimpflug imaging. Closest agreement was between OCT and VHF digital ultrasound with a bias of -8.45 µm, 95% LoA ±13.2 µm. Least agreement was between OCT and Scheimpflug imaging with a bias of -19.2 µm, 95% LoA ±19.2 µm. Bias between VHF digital ultrasound and Scheimpflug imaging was -10.7 µm, 95% LoA ±20.0 µm. No relationship was observed between difference in central corneal thickness measurements and mean central corneal thickness. Results were similar for minimum corneal thickness.

CONCLUSIONS

Central and minimum corneal thickness was measured thinnest by OCT and thickest by Scheimpflug imaging in both groups. A clinically significant bias existed between Scheimpflug imaging and the other two modalities.

Difference of refraction values between standard autorefractometry and Plusoptix

Aim: Comparison between the objective refraction measurement results determined with Topcon KR-8900 standard autorefractometer and Plusoptix A09 photo-refractometer in children. Material and methods: A prospective transversal study was performed in the Department of Ophthalmology of "Sf. Spiridon" Hospital in Iași on 90 eyes of 45 pediatric patients, with a mean age of 8,82 ± 3,52 years, examined with noncycloplegic measurements provided by Plusoptix A09 and cycloplegic and noncycloplegic measurements provided by Topcon KR-8900 standard autorefractometer. The clinical parameters compared were the following: spherical equivalent (SE), spherical and cylindrical values, and cylinder axis. Astigmatism was recorded and evaluated with the cylindrical value on minus after transposition. The statistical calculation was performed with paired t-tests and Pearson's correlation analysis. All the data were analyzed with SPSS statistical package 19 (SPSS for Windows, Chicago, IL). Results: Plusoptix A09 noncycloplegic values were relatively equal between the eyes, with slightly lower values compared to noncycloplegic auto refractometry. Mean (± SD) measurements provided by Plusoptix AO9 were the following: spherical power 1.11 ± 1.52, cylindrical power 0.80 ± 0.80, and spherical equivalent 0.71 ± 1.39. The noncycloplegic auto refractometer mean (± SD) measurements were spherical power 1.12 ± 1.63, cylindrical power 0.79 ± 0,77 and spherical equivalent 0.71 ± 1.58. The cycloplegic auto refractometer mean (± SD) measurements were spherical power 2.08 ± 1.95, cylindrical power 0,82 ± 0.85 and spherical equivalent 1.68 ± 1.87. 32% of the eyes were hyperopic, 2.67% were myopic, 65.33% had astigmatism, and 30% eyes had amblyopia. Conclusions: Noncycloplegic objective refraction values were similar with those determined by autorefractometry. Plusoptix had an important role in the ophthalmological screening, but did not detect higher refractive errors, justifying the cycloplegic autorefractometry.

Cross-sectional pupillographic evaluation of relative afferent pupillary defect in age-related macular degeneration

To evaluate, using pupillography, the difference between eyes affected by age-related macular degeneration and their contralateral normal eyes with regard to the mean relative afferent pupillary defect (RAPD) score. Also, to ascertain any correlations between this difference in RAPD score and differences in visual acuity or age-related macular degeneration (AMD) dimensions. Measurements were made using the RAPDx pupillographer (Konan Medical, Nishinomiya, Japan), which analyzes pupil response to light stimulation. Both best corrected visual acuity (converted to logMAR) and greatest linear dimension (GLD; calculated on the basis of fluorescence angiography images) were measured. The correlations between RAPD difference and logMAR difference, and GLD difference were then analyzed. The study included 32 patients (18 men, 14 women; mean age = 74.8 ± 9.7 years) who had AMD in 1 eye and a normal fundus in the contralateral eye. Mean resting pupil diameter, mean latency onset of constriction, mean velocity of constriction, and recovery were not significantly different in AMD eyes compared with normal eyes. The mean amplitude of constriction was smaller (P = 0.028), and the mean latency of maximum constriction was shorter (P = 0.0013) in AMD eyes than in normal eyes. Regarding RAPD scores, there was a significant correlation between visual acuity difference and RAPD score differences of both amplitude (P < 0.001, r = 0.53) and latency (P = 0.034, r = 0.33). GLD difference was also significantly correlated with differences in both amplitude (P = 0.021, r = 0.36) and latency (P = 0.033, r = 0.33) scores. RAPD outcomes were correlated with visual acuity and AMD dimension. Automated pupillography may be a useful tool in monitoring the progression of AMD and assessing changes in retinal function that result from novel interventions.

Measurement variability of the TearLab Osmolarity System

PURPOSE

To independently assess the measurement variability of TearLab System in a clinical setting of one visit and to estimate the minimum number of measurements required for reliable readings of tear osmolarity.

METHODS

Ten consecutive osmolarity measurements were taken from both eyes by the same examiner at one visit for fourteen subjects. The ocular surface disease index symptoms questionnaire and tear film break up time were also performed. Group average cumulative mean and cumulative coefficient of variation were calculated to assess the TearLab measurement variation. Repeated application of Thompson's tau method was performed to identify the outliers in tear osmolarity readings for each eye. Results from both eyes were analysed separately.

RESULTS

Up to two randomly occurring outlying values in 10 consecutive measurements were found in 19 out of 28 measured eyes. No statistically significant differences between the left and right eye were found for the group mean and group standard deviation (paired t-test, p=0.099 and p=0.068, respectively), however the cumulative coefficient of variation indicated higher measurement group variability on one eye. Estimated cumulative coefficient of variation indicated the minimum of three consecutive acquisitions required for the measurement to be reliable.

CONCLUSIONS

TearLab Osmolarity System required at least three consecutive measurements to be taken in order to provide clinically reliable tear osmolarity readings. Also, taking the maximum osmolarity value for detecting dry eye disease should be viewed with caution since outlying readings of tear osmolarity frequently occur.

Comparison of Anterior Segment Parameters Obtained by Dual-Scheimpflug Analyzer Before and After Cycloplegia in Children

PURPOSE

To assess the changes of anterior segment parameters with cycloplegia.

METHODS

A cross-sectional study of healthy pediatric patients was performed. Anterior segment parameters were obtained by the Galilei Dual-Scheimpflug analyzer (Ziemer Group, Port, Switzerland) before and 40 minutes after the instillation of cyclopentolate. The effect of gender was evaluated.

RESULTS

There were 43 boys and 50 girls with a mean age of 7.76 ± 2.7 years. There was a significant increase in anterior chamber depth, anterior chamber volume, and pupil diameter after the cycloplegia (P < .05). The anterior chamber angle increased after cycloplegia in the nasal, temporal, and inferior quadrants (P < .05), but not in the superior quadrant (P > .05). The mean values of anterior segment parameters were similar in both genders.

CONCLUSIONS

The values of anterior chamber depth, anterior chamber volume, anterior chamber angle, and pupil diameter measured with the Galilei Dual-Scheimpflug analyzer increased significantly after cycloplegia. Gender did not have an effect on anterior segment parameters. [J Pediatr Ophthalmol Strabismus. 2016;53(4):234-237.].

Trans-palpebral illumination: an approach for wide-angle fundus photography without the need for pupil dilation

It is technically difficult to construct wide-angle fundus imaging devices due to the complexity of conventional transpupillary illumination and imaging mechanisms. We report here a new method, i.e., trans-palpebral illumination, for wide-angle fundus photography without the need for pupil dilation. By constructing a smartphone-based prototype imaging device, we demonstrated a 152° view in a single-shot image. The unique combination of low-cost smartphone design and automatic illumination optimization promises an affordable solution to conduct telemedicine assessment of eye diseases, which will improve access to eye care for patients in rural and underserved areas.

Validation of the facial assessment by computer evaluation (FACE) program for software-aided eyelid measurements

The aim of this article is to validate the accuracy of Facial Assessment by Computer Evaluation (FACE) program in eyelid measurements. Sixteen subjects between the ages of 27 and 65 were included with IRB approval. Clinical measurements of upper eyelid margin reflex distance (MRD1) and inter-palpebral fissure (IPF) were obtained. Photographs were then taken with a digital single lens reflex camera with built-in pop-up flash (dSLR-pop) and a dSLR with lens-mounted ring flash (dSLR-ring) with the cameras upright, rotated 90, 180, and 270 degrees. The images were analyzed using both the FACE and ImageJ software to measure MRD1 and IPF.Thirty-two eyes of sixteen subjects were included. Comparison of clinical measurement of MRD1 and IPF with FACE measurements of photos in upright position showed no statistically significant differences for dSLR-pop (MRD1: p = 0.0912, IPF: p = 0.334) and for dSLR-ring (MRD1: p = 0.105, IPF: p = 0.538). One-to-one comparison of MRD1 and IPF measurements in four positions obtained with FACE versus ImageJ for dSLR-pop showed moderate to substantial agreement for MRD1 (intraclass correlation coefficient = 0.534 upright, 0.731 in 90 degree rotation, 0.627 in 180 degree rotation, 0.477 in 270 degree rotation) and substantial to excellent agreement in IPF (ICC = 0.740, 0.859, 0.849, 0.805). In photos taken with dSLR-ring, there was excellent agreement of all MRD1 (ICC = 0.916, 0.932, 0.845, 0.812) and IPF (ICC = 0.937, 0.938, 0.917, 0.888) values. The FACE program is a valid method for measuring margin reflex distance and inter-palpebral fissure.

Medical Devices; Ophthalmic Devices; Classification of the Diurnal Pattern Recorder System. Final order

The Food and Drug Administration (FDA) is classifying the diurnal pattern recorder system into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the diurnal pattern recorder system's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

A novel device for accurate and efficient testing for vision-threatening diabetic retinopathy

AIMS

To evaluate the performance of the RETeval device, a handheld instrument using flicker electroretinography (ERG) and pupillography on undilated subjects with diabetes, to detect vision-threatening diabetic retinopathy (VTDR).

METHODS

Performance was measured using a cross-sectional, single armed, non-interventional, multi-site study with Early Treatment Diabetic Retinopathy Study 7-standard field, stereo, color fundus photography as the gold standard. The 468 subjects were randomized to a calibration phase (80%), whose ERG and pupillary waveforms were used to formulate an equation correlating with the presence of VTDR, and a validation phase (20%), used to independently validate that equation. The primary outcome was the prevalence-corrected area under the receiver operating characteristic (ROC) curve for the detection of VTDR.

RESULTS

The area under the ROC curve was 0.86 for VTDR. With a sensitivity of 83%, the specificity was 78% and the negative predictive value was 99%. The average testing time was 2.3 min.

CONCLUSIONS

With a VTDR prevalence similar to that in the U.S., the RETeval device will identify about 75% of the population as not having VTDR with 99% accuracy. The device is simple to use, does not require pupil dilation, and has a short testing time.

Current and Next Generation Portable Screening Devices for Diabetic Retinopathy

Diabetic retinopathy (DR) is the leading cause of legal blindness in the United States, and with the growing epidemic of diabetes, a global increase in the incidence of DR is inevitable, so it is of utmost importance to identify the most cost-effective tools for DR screening. Emerging technology may provide advancements to offset the burden of care, simplify the process, and provide financially responsible methods to safely and effectively optimize care for patients with diabetes mellitus (DM). We review here currently available technology, both in production and under development, for DR screening. Preliminary results of smartphone-based devices, "all-in-one" devices, and alternative technologies are encouraging, but are largely pending verification of utility when used by nonophthalmic personnel. Further research comparing these devices to current nonportable telemedicine strategies and clinical fundus examination is necessary to validate these techniques and to potentially overcome the poor compliance around the globe of current strategies for DR screening.

SmartEye: Developing a Novel Eye Tracking System for Quantitative Assessment of Oculomotor Abnormalities

Eye movements are a continuous and ubiquitous part of sensory perception. To properly generate highly accurate and co-ordinate ocular movements, a vast network of brain areas are engaged, from low-level visual processing to motor control of gaze orientation. This renders oculomotor system vulnerable to various neurological disorders with unique clinical patterns. Therefore, oculomotor examination can serve as an early and sensitive indicator for various neurological conditions. A simple-to-use, clinically valid system for objectively assessing the oculomotor function can thus bring a paradigm shift in diagnosis and treatment of brain disorders. In principal accordance, this paper presents a gaze assessment tool, called SmartEye, which is based on eye fixation, smooth pursuit, and blinking in response to both static and dynamic visual stimuli. The gaze related indices were evaluated in real-time by SmartEye and these were mapped to the reported pathological state in chronic ( > 3 months) patients with stroke. Our preliminary feasibility study with eight pairs of chronic ( > 3 months) stroke survivors and healthy individuals revealed that gaze related indices in response to both static and dynamic visual stimuli may serve as potential quantitative biomarkers for stroke assessment.

Feasibility of Spectral Domain Optical Coherence Tomography Acquisition Using a Handheld Versus Conventional Tabletop Unit

PURPOSE

Patients afflicted with ocular complications of diabetes represent a diverse demographic who often cannot undergo spectral-domain optical coherence tomography (SD-OCT) imaging of the retina due to postural restraints. Our pilot study compared imaging acquisition methods using SD-OCT in the handheld (HH) mode versus the conventional tabletop (TT) method.

METHODS

Our study included 22 undilated eyes of 22 subjects (mean ± SD age, 35.8 ± 16.8 years) imaged using HH and TT iVue SD-OCT (Optovue, Fremont, CA). Statistical analysis was performed using Microsoft Excel 12.2.7 (Microsoft Corporation, Redmond, WA) software with an accepted significance of P < .05.

RESULTS

Strong intraclass correlation coefficient was observed for (1) overall (.97), superior (.93), and inferior (.94) ganglion cell complex thickness, and (2) central (.98), inferior (.90), superior (.92), nasal (.94), and temporal (.93) macular retinal thickness. Mean scan quality index was adequate but lower in HH versus TT SD-OCT (62.8 vs 68.1, respectively; P < .0001). Multiple attempts for adequate imaging were required more frequently in HH versus TT SD-OCT (34% vs 5%, respectively; P < .001).

CONCLUSION

HH SD-OCT may be a feasible alternative to TT SD-OCT in select situations, especially in patients suffering from diabetic complications with limited mobility.

ROPtool analysis of images acquired using a noncontact handheld fundus camera (Pictor)--a pilot study

The presence of plus disease is the primary indication for treatment of retinopathy of prematurity (ROP), but its diagnosis is subjective and prone to error. ROPtool is a semiautomated computer program that quantifies vascular tortuosity and dilation. Pictor is an FDA-approved, noncontact, handheld digital fundus camera. This pilot study evaluated ROPtool's ability to analyze high-quality Pictor images of premature infants and its accuracy in diagnosing plus disease compared to clinical examination. In our small sample of images, ROPtool could trace and identify the presence of plus disease with high accuracy.

The Diabetic Retinopathy Screening Workflow: Potential for Smartphone Imaging

Complications of diabetes mellitus, namely diabetic retinopathy and diabetic maculopathy, are the leading cause of blindness in working aged people. Sufferers can avoid blindness if identified early via retinal imaging. Systematic screening of the diabetic population has been shown to greatly reduce the prevalence and incidence of blindness within the population. Many national screening programs have digital fundus photography as their basis. In the past 5 years several techniques and adapters have been developed that allow digital fundus photography to be performed using smartphones. We review recent progress in smartphone-based fundus imaging and discuss its potential for integration into national systematic diabetic retinopathy screening programs. Some systems have produced promising initial results with respect to their agreement with reference standards. However further multisite trialling of such systems' use within implementable screening workflows is required if an evidence base strong enough to affect policy change is to be established. If this were to occur national diabetic retinopathy screening would, for the first time, become possible in low- and middle-income settings where cost and availability of trained eye care personnel are currently key barriers to implementation. As diabetes prevalence and incidence is increasing sharply in these settings, the impact on global blindness could be profound.