Comparison of an objective method of measuring bulbar redness to the use of traditional grading scales

Comparing Intracanalicular and Topical Steroid Use in Patients Undergoing Pterygium Surgery

OBJECTIVE

The study received funding from Ocular Therapeutix, Inc., Bedford, MA.We undertook this study to compare the efficacy of intracanalicular dexamethasone 0.4 mg with topical prednisolone acetate (PA) 1% in controlling postoperative pain and inflammation in patients undergoing pterygium surgery.

METHODS

This was an open-label, prospective, interventional, nonrandomized comparative trial. Thirty patients were assigned to one of the following groups: Group A [intracanalicular insert of 0.4 mg dexamethasone placed into upper and lower puncta during the procedure, followed by at postoperative month 1 visit institution of topical PA 1% twice daily × 2 weeks then once daily × 2 weeks] or Group B [nonintervention group with institution on postoperative day 1 topical PA 1% every 2 hours × 2 weeks then four times per day × 2 weeks then twice daily × 2 weeks then once daily × 2 weeks].

RESULTS

Fifteen cases and 15 controls were enrolled. There was no statistical difference in patient-reported pain or satisfaction between the case and control groups at 1 day; 1 week; and 1, 3, and 6 months postoperatively. There was no significant difference in time to an ocular hyperemia score of 0 between the two groups. There was no difference in the rate of corneal reepithelialization and recurrence rate (two controls). Nine eyes had transient ocular hypertension (seven cases and two controls).

CONCLUSION

Intracanalicular dexamethasone 0.4 mg may reduce the medication burden for patients who need prolonged postoperative steroid therapy as is routine in the setting of pterygium surgery. It is a safe and effective alternative to PA 1% drops alone for postoperative control of pain and inflammation in pterygium surgery.

Impact of Plasma Rich in Growth Factors (PRGF) Eye Drops on Ocular Redness and Symptomatology in Patients with Dry Eye Disease

Background and Objectives: Dry eye disease (DED) is a common and very symptomatic pathology that affects normal daily activity. The aim of the study was to evaluate the efficacy of plasma rich in growth factors (PRGF) added to one routine treatment protocol for DED (artificial tears substitutes, lid hygiene, and anti-inflammatory therapy). Materials and Methods: Patients were divided into two groups of treatment: standard treatment group (n = 43 eyes) and PRGF group (n = 59). Patients' symptomatology (inferred from OSDI and SANDE questionnaires), ocular inflammation, tear stability, and ocular surface damage were analyzed at baseline and after 3 months of treatment. Results: OSDI test scores were significantly lower in both groups (p < 0.001). SANDE frequency test scores also improved statistically, with differences between groups (p = 0.0089 SANDE frequency and p < 0.0119 SANDE severity). There was a greater reduction in ocular redness (ocular inflammation) in the PRGF group (p < 0.0001) and fluorescein tear break-up time was significantly improved in the PRGF group (p = 0.0006). No significant changes were found in terms of ocular surface damage. No adverse events were obtained in either group. Conclusions: The addition of PRGF to the standard treatment of DED, according to the results obtained, proved to be safe and produced an improvement in ocular symptomatology and signs of inflammation, particularly in moderate and severe cases, when compared to standard treatment.

Developing a Deep Learning Model to Evaluate Bulbar Conjunctival Injection with Color Anterior Segment Photographs

The present research aims to evaluate the feasibility of a deep-learning model in identifying bulbar conjunctival injection grading. Methods: We collected 1401 color anterior segment photographs demonstrating the cornea and bulbar conjunctival. The ground truth was bulbar conjunctival injection scores labeled by human ophthalmologists. Two convolutional neural network-based models were constructed and trained. Accuracy, precision, recall, F1-score, Kappa, and the area under the curve (AUC) were calculated to evaluate the efficiency of the deep learning models. The micro-average and macro-average AUC values for model grading bulbar conjunctival injection were 0.98 and 0.98, respectively. The deep learning model achieved a high accuracy of 87.12%, a precision of 87.13%, a recall of 87.12%, an F1-score of 87.07%, and Cohen's Kappa of 0.8153. The deep learning model demonstrated excellent performance in evaluating the severity of bulbar conjunctival injection, and it has the potential to help evaluate ocular surface diseases and determine disease progression and recovery.

Ocular redness - I: Etiology, pathogenesis, and assessment of conjunctival hyperemia

The translucent appearance of the conjunctiva allows for immediate visualization of changes in the circulation of the conjunctival microvasculature consisting of extensive branching of superficial and deep arterial systems and corresponding drainage pathways, and the translucent appearance of the conjunctiva allows for immediate visualization of changes in the circulation. Conjunctival hyperemia is caused by a pathological vasodilatory response of the microvasculature in response to inflammation due to a myriad of infectious and non-infectious etiologies. It is one of the most common contributors of ocular complaints that prompts visits to medical centers. Our understanding of these neurogenic and immune-mediated pathways has progressed over time and has played a critical role in developing targeted novel therapies. Due to a multitude of underlying etiologies, patients must be accurately diagnosed for efficacious management of conjunctival hyperemia. The diagnostic techniques used for the grading of conjunctival hyperemia have also evolved from descriptive and subjective grading scales to more reliable computer-based objective grading scales.

Ocular redness - II: Progress in development of therapeutics for the management of conjunctival hyperemia

Conjunctival hyperemia is one of the most common causes for visits to primary care physicians, optometrists, ophthalmologists, and emergency rooms. Despite its high incidence, the treatment options for patients with conjunctival hyperemia are restricted to over-the-counter drugs that provide symptomatic relief due to short duration of action, tachyphylaxis and rebound redness. As our understanding of the immunopathological pathways causing conjunctival hyperemia expands, newer therapeutic targets are being discovered. These insights have also contributed to the development of animal models for mimicking the pathogenic changes in microvasculature causing hyperemia. Furthermore, this progress has catalyzed the development of novel therapeutics that provide efficacious, long-term relief from conjunctival hyperemia with minimal adverse effects.

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.

Conjunctival Vascular Adaptation Related to Ocular Comfort in Habitual Contact Lens Wearers

PURPOSE

We sought to investigate the bulbar conjunctival vascular responses in habitual contact lens (HCL) and non-contact lens (NCL) wearers after short-term lens wear and their relationships with ocular comfort.

DESIGN

A prospective, comparative before-and-after study.

METHODS

Twenty-seven subjects (13 HCL and 14 NCL wearers) were enrolled. Microvasculature and microcirculation on the temporal bulbar conjunctiva were imaged at baseline and 0.5 and 6 hours after wearing contact lenses (1-Day Acuvue TruEye; base curve, 8.5 mm; power, -0.50 diopters) on both eyes. The measurements included vessel diameter (D), axial (VA), and cross-sectional (VS) blood flow velocities, blood flow volume (Q), and vessel density (Dbox) and complexity (D0). A Contact Lens User Experience (CLUE) questionnaire was used to assess ocular comfort.

RESULTS

No significant change (P > .05) was observed in D, VA, VS, Q, Dbox, and D0 in the HCL wearers after contact lens wear. By contrast, VA, VS, Q, Dbox, and D0 increased significantly after lens wear (after 0.5 and 6 hours) in NCL wearers compared with baseline (P < .05). Moreover, the changes from the baseline to 0.5 hours (VA, VS, and Dbox) and 6 hours (VA, VS, Q, Dbox, and D0) after contact lens wear in NCL wearers were significantly greater than that in HCL wearers (P < .05). The CLUE score 6 hours after lens wear was higher in HCL wearers than in NCL wearers (P < .05). It was also significantly correlated with VA, VS, and D0 after 6-hour lens wear in HCL wearers (P < .05).

CONCLUSIONS

This is the first study to reveal the relationship between ocular comfort and conjunctival vascular responses in habitual contact lens wearers.

Identification of Leukocytes Associated With Midday Fogging in the Post-Lens Tear Film of Scleral Contact Lens Wearers

Purpose

Midday fogging is a frequent complaint among scleral contact lens (ScCL) wearers, and the mechanism and cause of this is unknown. The purpose of this investigation was to understand the relation between midday fogging, ocular surface leukocytes, and ScCL fitting characteristics.

Methods

Subjects arrived at a clinical exam having worn ScCLs for at least 4 hours. ScCL were removed, and 150 μL of phosphate-buffered saline (PBS) was used to wash the bowl of the ScCL. Eyes were washed post-ScCL removal with 5 mL PBS per eye. Wash solutions were collected and leukocytes were then isolated and counted, followed by assessment with flow cytometry. Samples from the post-lens tear fluid were stained with fluorescently labeled antibodies to detect leukocyte distributions.

Results

Thirty-nine eyes from 19 adapted, full-time, ScCL wearers were included, and 46% presented with midday fogging. ScCL corneal clearance was 246 ± 61 μm for nonfoggers, while it was 308 ± 98 μm for those with fogging (P < 0.05). On average, the number of leukocytes collected from the ScCL bowl (9551 ± 18,926) was greater than the number of leukocytes recovered from the eye wash (2195 ± 4384, P < 0.02). ScCL corneal clearance was associated with the presence of fogging, with an odds ratio of 2.24 (95% confidence interval = 1.48–3.38, P < 0.001).

Conclusions

Leukocytes, predominated by neutrophils, are present in the post-lens tear film of ScCL wearers, and in particular wearers with greater ScCL corneal clearance have greater odds of having midday fogging.

Inter-visit measurement variability of conjunctival vasculature and circulation in habitual contact lens wearers and non-lens wearers

Background

The inter-visit variation of measuring bulbar conjunctival microvasculature and microcirculation needs to be considered when the results from multiple visits are interpreted. This study examined the inter-visit variability of measuring conjunctival microvasculature and microcirculation in habitual contact lens (HCL) wearers and non-contact lens (NCL) wearers.

Methods

Twenty-eight subjects were recruited including 13 HCL wearers (10 females and 3 males; mean age ± standard deviation, 25.8 ± 4.6 years) who had worn contact lenses on a daily basis for at least 3 years and 15 NCL wearers (10 females and 5 males, age 25.5 ± 4.0 years) were recruited. The temporal bulbar conjunctiva was imaged using a functional slit-lamp bio-microscope (FSLB) imaging system. FSLB imaging was performed in the morning when the HCL wearers did not wear their lenses. The measurements included conjunctival vessel diameter, vessel density, blood flow velocity and flow volume. In addition, conjunctival microvasculature was analyzed using monofractal (Dbox, representing vessel density) and multifractal (D0 representing vessel complexity) analyses. The repeated measurement was conducted at least one week after the first visit and both eyes of each participant were imaged. The coefficient of variation (CV) was calculated as the standard deviation of the differences between test and re-test then divided by the mean of the measurements. The intra-class correlation coefficient (ICC) was also calculated.

Results

No significant differences of all vascular measurements in both the right and left eyes were found between two groups (P > 0.05). Between two measurements on two different visits, the CV was from 2.4% (vessel density D0) to 63.5% (blood flow volume Q) in HCL wearers and from 3.4% (D0) to 40.6% (blood flow volume) in NCL wearers. The ICC was from 0.60 (vessel diameter) to 0.81 (axial blood flow velocity VA) in HCL wearers and from 0.44 (Q) to 0.68 (cross-sectional blood flow velocity VS) in NCL wearers.

Conclusions

The measurement variability of the vessel density of the bulbar conjunctiva appeared to have the smallest inter-visit variation. The measurement variability of the vasculature and circulation in HCL wearers were similar to that in NCL wearers.

Comparison of different smartphone cameras to evaluate conjunctival hyperaemia in normal subjects

Despite the significant advantages that smartphones’ cameras can provide in teleophthalmology and artificial intelligence applications, their use as black-box systems for clinical data acquisition, without adequate information of the quality of photographs can compromise data accuracy. The aim of this study is to compare the objective and subjective quantification of conjunctival redness in images obtained with calibrated and non-calibrated cameras, in different lighting conditions and optical magnifications. One hundred ninety-two pictures of the eye were taken in 4 subjects using 3 smartphone cameras{Bq, Iphone, Nexus}, 2 lighting levels{high 815 lx, low 122 lx} and 2 magnification levels{high 10x, low 6x}. Images were duplicated: one set was white balanced and color corrected (calibrated) and the other was left as it was. Each image was subjective and objectively evaluated. There were no significant differences in subjective evaluation in any of the conditions whereas many statistically significant main effects and interaction effects were shown for all the objective metrics. The clinician’s evaluation was not affected by different cameras, lighting conditions or optical magnifications, demonstrating the effectiveness of the human eye’s color constancy properties. However, calibration of a smartphone’s camera is essential when extracting objective data from images.

A new scale for the assessment of conjunctival bulbar redness

PURPOSE

Current scales for assessment of bulbar conjunctival redness have limitations for evaluating digital images. We developed a scale suited for evaluating digital images and compared it to the Validated Bulbar Redness (VBR) scale.

METHODS

From a digital image database of 4889 color corrected bulbar conjunctival images, we identified 20 images with varied degrees of redness. These images, ten each of nasal and temporal views, constitute the Digital Bulbar Redness (DBR) scale. The chromaticity of these images was assessed with an established image processing algorithm. Using 100 unique, randomly selected images from the database, three trained, non-physician graders applied the DBR scale and printed VBR scale. Agreement was assessed with weighted Kappa statistics (K_w).

RESULTS

The DBR scale scores provide linear increments of 10 from 10-100 when redness is measured objectively with an established image processing algorithm. Exact agreement of all graders was 38% and agreement with no more than a difference of ten units between graders was 91%. K_w for agreement between any two graders ranged from 0.57 to 0.73 for the DBR scale and from 0.38 to 0.66 for the VBR scale. The DBR scale allowed direct comparison of digital to digital images, could be used in dim lighting, had both temporal and nasal conjunctival reference images, and permitted viewing reference and test images at the same magnification.

CONCLUSION

The novel DBR scale, with its objective linear chromatic steps, demonstrated improved reproducibility, fewer visualization artifacts and improved ease of use over the VBR scale for assessing conjunctival redness.

Daily versus monthly disposable contact lens: Which is better for ocular surface physiology and comfort?

PURPOSE

To investigate the effect of soft contact lenses (SCL) wearing modality and lens materials on the changes in conjunctival bulbar and limbal redness and conjunctival and corneal staining after two months of SCL wear. Comfort level was also analyzed.

METHODS

In this longitudinal clinical trial, forty-seven neophyte myopic subjects were fitted with a monthly disposable lens (lotrafilcon-B or comfilcon-A or balafilcon-A) in one eye and a daily disposable lens (nelfilcon-A or stenofilcon-A or nesofilcon-A) in the other eye, randomly selected. Conjunctival bulbar and limbal redness and conjunctival and corneal staining were evaluated before and after lens wear. Effect of lens wearing modality and lens materials on these changes was also determined. Level of comfort was evaluated subjectively twice per day. Comfort level and reduction in end-of-day comfort were compared between different lens wearing modalities and materials.

RESULTS

Bulbar and limbal redness and conjunctival and corneal staining were increased (p<0.001) after lens wear, and changes were similar with daily and monthly disposable lens wear (p>0.05). Limbal redness was associated with lens materials, and lotrafilcon-B induced the least among the studied lenses (p<0.05). There was no significant association between the wearing modality and the average comfort level and reduction of end-of-day comfort (p>0.05).

CONCLUSION

Two months of SCL wear increased conjunctival redness, conjunctival and corneal staining, which were not associated with the lens wearing modality. There was a reduction in end-of-day comfort, similar to daily and monthly lenses. The change in limbal redness and reduction in end-of-day comfort were associated with the characteristics of the lens material.

Evaluating Changes in Ocular Redness Using a Novel Automated Method

Purpose

To evaluate interobserver concordance in measured ocular redness among a group of raters using an objective computer-assisted method (ocular redness index [ORI]) and a group of clinicians using an ordinal comparative scale.

Methods

We conducted a prospective study to evaluate ocular redness in clinical photographs of 12 patients undergoing pterygium surgery. Photographs were acquired preoperatively, and at 1 week and 1 month postoperatively. One group of clinicians graded conjunctival redness in the photographs using an image-based comparative scale. A second group applied the ORI to measure redness in the same photographs. We evaluated redness change between time points, level of agreement among raters, and assessed redness score differences among observers within each group.

Results

Interobserver agreement using the image-based redness scale was 0.458 (P < 0.001). Interobserver agreement with the ORI was 0.997 (P < 0.001). We observed statistically significant differences among clinicians' measurements obtained with the image-based redness scale (P < 0.001). There were no significant differences among measurements obtained with the ORI (P = 0.27). We observed a significant change in redness between baseline and follow-up visits with all scoring methods. Detailed analysis of redness change was performed only in the ORI group due to availability of continuous scores.

Conclusion

Our findings suggest that the ORI scores provide higher consistency among raters than ordinal scales, and can discriminate redness changes that clinical observers often can miss.

Translational Relevance

The ORI may be a reliable alternative to measure ocular redness objectively in the clinic and in clinical trials.

Altered Bulbar Conjunctival Microcirculation in Response to Contact Lens Wear

PURPOSE

This study was conducted to determine blood flow velocities and corresponding vessel diameters to characterize the response of the bulbar conjunctival microvasculature to contact lens wear.

METHODS

A functional slit-lamp biomicroscope (FSLB), an adapted traditional slitlamp, was used to image the temporal bulbar conjunctiva of 22 healthy subjects before and after 6 hr of contact lens wear. All of the measurable venules on the conjunctiva were processed to yield vessel diameters and blood flow velocities.

RESULTS

The average blood flow velocity increased from 0.51±0.20 to 0.65±0.22 mm/sec (P<0.001) after 6 hr of lens wear. The blood flow velocity distribution showed a velocity increase that correlated with the vessel diameter increase from the baseline (r=0.826, P<0.05). This pattern maintained a similar trend after 6 hr of lens wear (r=0.925, P<0.05), and increased velocities were found across all of the vessel diameter ranges (P<0.001).

CONCLUSIONS

Blood flow velocity increases across all of the vessel diameter ranges in response to contact lens wear. Functional slitlamp biomicroscope is capable of characterizing the bulbar microvascular response to contact lens wear.

Objective Assessment of Ocular Surface Response to Contact Lens Wear in Presbyopic Contact Lens Wearers of Asian Descent

Introduction:

Contact lens wearers of Asian descent may be predisposed to experience microtrauma of the ocular surface as a result a thinner post-lens tear film and higher eyelid tension, and these effects would be anticipated to be most marked in an older population. The objective of this study was to quantify the mechanical effects of the study contact lenses on the ocular surface in a population of presbyopic contact lens wearers of Asian descent.

Methods:

Twenty established presbyopic contact lens wearers (hydrogel n=5, none habitual wearers of etafilcon A lenses; silicone hydrogel n=15) of Asian descent were refitted with etafilcon A multifocal daily disposable contact lenses (1-DAY ACUVUE MOIST MULTIFOCAL) for a period of 1 month of daily lens wear. The habitual modalities of wear were 45% daily disposable and 55% planned replacement. Digital photographs of the upper lid margins, nasal and temporal conjunctiva, and superior cornea were taken after 6 hr of wear of the participants' habitual contact lenses, after 1 day without contact lens wear, and after 6 hr of wear of the study contact lenses at the end of the 1-month period. The photographs were masked according to study visit and the staining extent measured using proprietary software.

Results:

Lid margin staining was significantly lower with the study contact lenses (2.0±1.0 mm²) than with the participants' own contact lenses (3.2±3.0 mm²) after 6 hr of wear, representing a mean staining decrease of 38% (P=0.010). Lid margin staining after 6 hr of wear of the study contact lenses was not different from that measured after 1 day without contact lenses (P=0.507). Limbal staining was also significantly less with the study contact lenses than with the participants' own contact lenses after 6 hr of wear (P=0.009). There was minimal upper corneal staining, and the degree was similar with the study and habitual lenses.

Conclusions:

Etafilcon A material, worn under a daily disposable modality, was shown to reduce upper lid margin and limbal staining in presbyopic contact lens wearers of Asian descent compared with the wearers' own contact lenses. Because of the high preponderance of dry eye amongst presbyopes, material selection is of importance and consideration should be given to the lens–ocular surface interaction.

Assessing ocular bulbar redness: a comparison of methods

PURPOSE

We consider whether quantification of ocular bulbar redness, using image processing of relative Red-channel activity (Red-value), can be applied to a clinical sample and how this approach compares to an automated bulbar redness grading technique (Oculus Keratograph 5M, R-scan).

METHODS

Red-values from dry eye patients (n = 25) were determined using image processing of digital photographs over the nasal bulbar conjunctiva. Red-values were compared with subjective grades from six clinicians who graded the images using the IER scale. We considered the level of agreement between the Red-value and automated bulbar redness scores from the commercial instrument (R-scan). Scoring variability for each technique was assessed using the geometric coefficient of variation (gCoV, %). Agreement between techniques was considered with Bland-Altman analyses.

RESULTS

Red-values showed a strong linear relationship (R(2) = 0.99) to the R-scan. The Red-value had least variability (gCoV = 0.97%, 95% CI: 0.76-1.35%). The IER grade showed a linear relationship with Red-value (R(2) = 0.99), bound by a floor effect; it did not discriminate changes in redness below a threshold of 1.75 units (Red-value = 33.0%), after which it paralleled the redness returned by the R-scan. Intra-method variability for the redness returned by the R-scan (gCoV = 9.84%, 95% CI: 7.60-13.94%) and IER grades (gCoV = 7.30%, 95% CI: 1.73-10.31%) was similar (p > 0.05). Bland-Altman analysis showed the R-scan was consistently biased towards lower absolute redness scores than the IER.

CONCLUSIONS

Digital imaging processing, using relative Red-channel activity, was the least variable of the three techniques. The R-scan and IER showed similar intra-observer variability. The linear relationship between R-scan and Red-value suggests that the R-scan could be derived using similar methods.

Assessment of Bulbar Redness with a Newly Developed Keratograph

PURPOSE

To determine the validity and reliability of the clinical assessment of bulbar redness (BR) using a newly developed corneal topographer.

METHODS

This is a cross-sectional diagnostic evaluation study. The BR scores [Oculus Index (OI)] from 30 eyes of 26 patients with different degrees of conjunctival hyperemia were assessed and scored automatically using a new method: a keratograph equipped with scanning and scoring software. The values obtained via this system were correlated with three image-based comparative subjective scales: the Institute for Eye Research (IER), the Efron, and the Validated Bulbar Redness (VBR) grading scales. The IER and Efron scores were interpolated to 0.1 unit, and the VBR scores were interpolated to 1 unit. We also evaluated the repeatability of each method and the level of agreement between the OI score and the scores achieved using the three other image-based methods.

RESULTS

There was a significant correlation between the OI score and the scores obtained with the IER (r = 0.921, p < 0.001), Efron (r = 0.958, p < 0.001), and VBR (r = 0.965, p < 0.001) scales. The intraobserver intraclass correlation coefficients were 0.947, 0.874, 0.810, and 0.920 for the OI, IER, Efron, and VBR, respectively, and the intraobserver coefficients of repeatability were 13.924, 16.111, 17.684, and 16.900, respectively. Furthermore, the interobserver intraclass correlation coefficients were 0.889, 0.880, 0.884, and 0.881 for the OI, IER, Efron, and VBR, respectively, and the interobserver coefficients of repeatability were 15.934, 16.366, 22.059, and 21.373, respectively.

CONCLUSIONS

The OI is an objective and reliable method for scoring BR. Its reproducibility was the highest of all the four modalities. The keratograph is recommended, therefore, as a suitable alternative for BR assessment.

The Measurement of Bulbar Hyperemia: Challenges and Pitfalls

Purpose

To review methods of assessing bulbar redness, particularly with respect to the practicality of comparing different rating systems.

Methods

The published literature was reviewed and discussed by a panel of experts and a narrative review prepared.

Results

Bulbar hyperemia is a common clinical sign and an important indicator of ocular disease. As bulbar hyperemia is a frequent side effect of topical glaucoma medications, accurate objective measurement is important to allow comparison of clinical studies. A number of different measurement systems have evolved to allow quantification of subjectively assessed redness to be rendered into a form that allows between-treatment comparisons and longitudinal changes in both clinical research and practice. Whereas widespread use of image-based rating scales has improved the assessment of bulbar redness in clinical practice and clinical research, these techniques are less than ideal. The scales are subject to an intrinsic subjectivity and are suboptimal in differentiating the physiologic phenomenon of bulbar hyperemia. There is also a degree of interobserver and intraobserver variation; in some studies, average variation in scores exceed half the extent of the whole scale. Moreover, a lack of interscale validation has led to confusion in comparing the results from clinical studies that use different scales. In a recent series of studies, cross-calibration between the various scales in use has been attempted.

Conclusions

Whereas naive comparisons between the results obtained in studies using different bulbar redness scales can lead to erroneous conclusions, the tools exist to permit meaningful comparisons between rating systems and scales.

Spectroscopic measurements in scleritis: bluish-red or deep red?

PURPOSE

To design a slit-lamp mountable spectrometer for the assessment of ophthalmic patients and to illustrate a potential clinical application by measuring the spectral characteristics of inflamed eyes of differing aetiologies.

METHODS

A slit lamp mountable instrument was designed and built, and methods for data analysis developed. Reflectance spectra were recorded from two patients with scleritis, three with non-scleritic red eyes and from two controls with non-inflamed eyes.

RESULTS

Measurements were reproducible and demonstrated statistically significant differences in the spectral characteristics between the three groups. Spectra from scleritic eyes revealed a relative increase in intensity of long wavelength red light, 650-740 nm, compared with non-scleritic red eyes. These longer wavelengths will be appreciated as dark red. There was no increase in relative intensity in the blue part of the spectrum in scleritic eyes.

CONCLUSIONS

Reproducible measurements of the eye were made using an innovative, slit-lamp mountable spectrometer and its functionality demonstrated by differentiating the spectra from eyes with differing pathologies. While intending only to illustrate one potential application; for the cases examined, our results indicate that inflamed scleritic eyes exhibit a longer wavelength red light with no increase in shorter wavelength blue light. Thus our measurements would seem to confirm that the perceived redness of scleritis differs from other red eyes. However, it is a deeper darker red and not a bluish one as traditionally described.

Development of automated conjunctival hyperemia analysis software

Conjunctival hyperemia is observed in a variety of ocular inflammatory conditions. The evaluation of hyperemia is indispensable for the treatment of patients with ocular inflammation. However, the major methods currently available for evaluation are based on nonquantitative and subjective methods. Therefore, we developed novel software to evaluate bulbar hyperemia quantitatively and objectively. First, we investigated whether the histamine-induced hyperemia of guinea pigs could be quantified by image analysis. Bulbar conjunctival images were taken by means of a digital camera, followed by the binarization of the images and the selection of regions of interest (ROIs) for evaluation. The ROIs were evaluated by counting the number of absolute pixel values. Pixel values peaked significantly 1 minute after histamine challenge was performed and were still increased after 5 minutes. Second, we applied the same method to antigen (ovalbumin)-induced hyperemia of sensitized guinea pigs, acquiring similar results except for the substantial upregulation in the first 5 minutes after challenge. Finally, we analyzed human bulbar hyperemia using the new software we developed especially for human usage. The new software allows the automatic calculation of pixel values once the ROIs have been selected. In our clinical trials, the percentage of blood vessel coverage of ROIs was significantly higher in the images of hyperemia caused by allergic conjunctival diseases and hyperemia induced by Bimatoprost, compared with those of healthy volunteers. We propose that this newly developed automated hyperemia analysis software will be an objective clinical tool for the evaluation of ocular hyperemia.

Evaluation of regional bulbar redness using an image-based objective method

AIM

To develop an image-based objective method to precisely evaluate regional ocular bulbar injection.

METHODS

Six healthy adult volunteers were photographed in four orientations (superior, inferior, nasal and temporal sides) with and without stimulating eye drops. Six line segments (covering 30°) were drawn 4mm away from the limbus on each image using ImageJ software. The graph peaks, which were derived from the areas under the line segments and corresponded to the cross-sectional grey-level of the vessels, were analyzed to obtain peak area, peak height/width (PH/PW), and peak numbers. Different-sized areas were selected to calculate the pixels based on the edge-detection algorithm. Also, conjunctival and superficial scleral vessels were analyzed separately.

RESULTS

This method had a smaller coefficient of variation, especially for PH/PW, in all four orientations. Hyperaemia parameters changed the least after challenging in the superior region. Moreover, 95% of the PH/PW ratios were greater than 0.87 in conjunctival vessels and less than 1.00 in superficial scleral vessels. PH/PW significantly increased in conjunctival vessels and changed less in superficial scleral vessels.

CONCLUSION

A new method of objectively assessing bulbar injection based on ocular surface images was developed. This method can be used to quantify ocular regional injection and to distinguish the superficial scleral and conjunctival vessels.

The Ocular Redness Index: a novel automated method for measuring ocular injection

PURPOSE

To develop and validate a novel automated system to assess ocular redness (OR) in clinical images.

METHODS

We developed a novel software that quantifies OR in digital images based on a mathematic algorithm using a centesimal continuous scoring scale. Subsequently, we conducted a study to validate the scores obtained with this system by correlating them with those obtained by two physicians using two image-based comparative subjective scales, the Efron and the Validated Bulbar Redness (VBR) grading scales. Additionally, we evaluated the level of clinical agreement between the Ocular Redness Index (ORI) score and the two image-based methods by means of the Bland-Altman analysis. Main outcome measures included correlation and level of agreement between the ORI score, Efron score, and the VBR score.

RESULTS

One hundred and two clinical photographs of eyes with OR were evaluated. The ORI scores significantly correlated with the scores obtained by the two clinicians using the Efron (Observer 1, R=0.925, P<0.001; Observer 2, R=0.857, P<0.001), and VBR (Observer 1, R=0.830, P<0.001; Observer 2, R=0.821, P<0.001) scales. The Bland-Altman analysis revealed levels of disagreement of up to 30 and 27 units for the ORI-Efron and ORI-VBR score comparisons, respectively.

CONCLUSIONS

The ORI provides an objective and continuous scale for evaluating ocular injection in an automated manner, and without need for a trained physician for scoring. The ORI may be used as a new alternative for objective OR evaluation in clinics and in clinical trials.

Influence of the blink interval on tear meniscus height in soft contact lens and nonlens wearers

PURPOSE

Tear meniscus height (TMH) is an indirect measurement of tear film volume. This study investigated the temporal changes in the TMH during the blink interval in the morning (8-9 am) and at the end of the day (5-6 pm) in both soft contact lens (CL) and nonlens wearers (NLW).

METHODS

Fifty participants (25 CL; 25 NLW) were evaluated for their subjective symptoms, TMH, noninvasive break up time, and bulbar hyperemia at the am and pm visits on the same day. The TMH was measured at set intervals between 2 and 15 sec during the blink interval, using an optical coherence tomographer.

RESULTS

The NLW group revealed no changes in a variety of symptoms during the day, whereas the CL group reported an increase in dryness (P=0.03) and grittiness (P=0.02) over the day. For both groups, the TMH and calculated tear meniscus volume revealed lower values immediately after the blink and increased progressively afterwards, mainly due to reflex tearing. The am tear meniscus volume values tended to be higher than the pm values for both groups, but this was not significant (NLW P=0.13; CL P=0.82). Noninvasive break up time deteriorated during the day for both groups but was only significant for the CL group (P=0.002), whereas bulbar hyperemia revealed no statistically significant change for either group.

CONCLUSIONS

Reflex tearing may play a substantial role in the TMH differences observed over the blink interval. Standardization of the time when a TMH measurement is performed will be valuable in comparing tear film clinical studies.

Image analyses of the kinetic changes of conjunctival hyperemia in histamine-induced conjunctivitis in Guinea pigs

BACKGROUND

Conjunctival hyperemia is the most common finding in patients with allergic conjunctivitis. Histamine is a typical chemical mediator involved in allergic conjunctivitis and induces hyperemia. Here, we investigated the kinetic changes in bulbar hyperemia induced by histamine in eyedrops.

METHODS

Male guinea pigs were challenged with histamine in eyedrops. Bulbar conjunctival images were taken every 10 seconds by a digital camera up to 8 minutes after histamine challenge, and the software program ImageJ was used to analyze the images. Images were binarized, and a region of interest unobscured by corneal and scleral vessels was selected as the evaluation area. Evaluations were carried out before and after histamine challenge by counting the numbers of absolute pixel values, percent changes in pixels, or the fractal dimension in acquired images.

RESULTS

After histamine challenge, the conjunctival vessel area continued to increase up to 5 minutes before stabilizing. The various parameters used to evaluate the images (numbers of absolute pixel values, percent change in pixels, or the fractal dimensions) markedly increased 1 minute after histamine challenge, gradually increased up to 5 minutes, and then gradually decreased before reaching a level that remained significantly higher than that before histamine challenge.

CONCLUSIONS

This is the first report to quantitatively evaluate bulbar hyperemia induced by histamine using image analysis. The development of software that can automatically yield meaningful values for hyperemia from hyperemia images will be a useful objective tool in clinical trials for evaluation of drug effects in animal models and in humans.