The disc damage likelihood scale (DDLS): interobserver agreement of a new grading system to assess glaucomatous optic disc damage

Inflammation and Neurodegeneration in Glaucoma: Isolated Eye Disease or a Part of a Systemic Disorder? - Serum Proteomic Analysis

Introduction

Glaucoma is the most common optic neuropathy and the leading cause of irreversible blindness worldwide, which affects 3.54% of the population aged 40-80 years. Despite numerous published studies, some aspects of glaucoma pathogenesis, serum biomarkers, and their potential link with other diseases remain unclear. Recent articles have proposed that autoimmune, oxidative stress and inflammation may be involved in the pathogenesis of glaucoma.

Methods

We investigated the serum expression of 92 inflammatory and neurotrophic factors in glaucoma patients. The study group consisted of 26 glaucoma patients and 192 healthy subjects based on digital fundography.

Results

Patients with glaucoma had significantly lower serum expression of IL-2Rβ, TWEAK, CX3CL1, CD6, CD5, LAP TGF-beta1, LIF-R, TRAIL, NT-3, and CCL23 and significantly higher expression of IL-22Rα1.

Conclusion

Our results indicate that patients with glaucoma tend to have lower levels of neuroprotective proteins and higher levels of neuroinflammatory proteins, similar to those observed in psychiatric, neurodegenerative and autoimmune diseases, indicating a potential link between these conditions and glaucoma pathogenesis.

Spotlight on the Disc-Damage Likelihood Scale (DDLS)

The disc damage likelihood scale (DDLS) is a tool for classifying glaucomatous structural changes to the optic disc based on the radial width of the neuroretinal rim at its thinnest location, or if no rim is present, the extent of absence of the rim. Unlike cup disc ratio (CDR), the DDLS also considers disc size. Twenty years after its first description, the aim of this review was to critically appraise evidence for the DDLS and evaluate its role in current practice. A literature search by two independent authors identified 33 relevant articles for inclusion. Five studies evaluated reproducibility, 5 diagnostic performance, and 2 studies examined ability to detect progression. Eleven studies evaluated correlation between DDLS and other markers of glaucoma. Despite the widespread availability of imaging devices such as optical coherence tomography (OCT), clinical examination of the optic disc remains an essential component of glaucoma diagnosis and monitoring. The DDLS provides a reliable method for semi-quantitative clinical grading of the optic disc in glaucoma, with higher reproducibility than methods such as CDR.

The role of the disc damage likelihood scale in glaucoma detection by community optometrists

PURPOSE

Recent guidelines recommend disc damage likelihood scale (DDLS) is recorded for all referrals of suspected glaucoma from community optometrists to hospital eye services (HES) in Scotland. This study aimed to determine whether lower DDLS grades were associated with higher rates of discharge at the first visit to HES.

METHODS

A retrospective analysis of 618 consecutive new referrals from community optometrists to a university hospital glaucoma service. 65 (10.5%) included DDLS graded by the community optometrist. A comprehensive eye examination and optical coherence tomography (OCT) was performed in the hospital glaucoma clinic and first visit discharge rate (FVDR) for different grades of DDLS compared. The relationship between DDLS and retinal nerve fibre layer (RNFL) thickness on OCT was also examined.

RESULTS

The FVDR for patients with DDLS recorded in the referral was 27.7% (18 of 65) compared to 25% (138 of 553) in those without DDLS (p = 0.631). The FVDR was 50% for those with a DDLS of 3 in the worse eye, decreasing to 32% and 21% for DDLS grades of 4 and 5 respectively. No patient with a DDLS ≥ 6 was discharged at the first visit and none with a DDLS < 4 (the cut off for consideration of referral in Scottish guidelines) were found to have glaucoma. There was a significant but weak inverse relationship between DDLS and RNFL thickness. The strongest relationship was with average RNFL thickness (r = -0.378, p < 0.01) followed by superotemporal (r = -0.359, p < 0.01) and inferotemporal (r = -0.353, p < 0.01) RNFL thickness.

CONCLUSIONS

In patients referred to HES with DDLS information included, lower DDLS grading was associated with higher odds of being discharged at the first visit. DDLS grading by community optometrists had a poor correlation with RNFL thickness measured using OCT.

The disc damage likelihood scale: Diagnostic accuracy and correlations with cup-to-disc ratio, structural tests and standard automated perimetry

Our objective was to compare the diagnostic accuracies of and to determine the correlations between the disc damage likelihood scale (DDLS) and anatomical and functional tests used for glaucoma detection. A total of 54 healthy subjects (54 eyes) and 47 primary open-angle glaucoma patients (47 eyes) were included in this cross-sectional observational study. DDLS scores and cup-to-disc (C/D) ratios were evaluated. Subjects underwent standard automated perimetry (SAP), optic disc and retinal nerve fiber layer (RNFL) imaging with time and spectral-domain optical coherence tomography (TD and SD-OCT), Heidelberg Retina Tomograph (HRT II), and scanning laser polarimetry (GDx-VCC). Areas under the receiver operating characteristic curves (AROCs) for DDLS and diagnostic tests parameters were calculated. DDLS correlations (Spearman's rank) among these parameters were analyzed. Fifty-four eyes were healthy and 47 had glaucoma, including 16 preperimetric glaucoma. DDLS, vertical and horizontal C/D ratios had the largest AROCs (0.92, 0.94 and 0.91, respectively). DDLS diagnostic accuracy was better than the accuracies of HRT II parameters, TD and SD-OCT RNFL thicknesses, and SAP mean deviation (MD) index. There were no significant differences between the accuracies of the DDLS and the C/D ratios, TD-OCT vertical (0.89) and horizontal (0.86) C/D ratios, TD-OCT C/D area ratio (0.89), and GDx-VCC NFI (0.81). DDLS showed significant strong correlations with vertical (r = 0.79) and horizontal (0.74) C/D ratios, and with the parameters vertical C/D ratio and C/D area ratio from HRT II (both 0.77) and TD-OCT (0.75 and 0.72, respectively). DDLS had significant moderate correlations with most of the other structural measurements and SAP MD. The optic disc clinical evaluation with DDLS system and C/D ratio demonstrated excellent accuracy in distinguishing glaucomatous from healthy eyes. DDLS had moderate to strong correlations with most structural and functional parameters. These findings stress the importance of optic disc clinical examination to detect glaucoma in a clinical scenario.

Evaluating objective and subjective quantitative parameters at the initial visit to predict future glaucomatous visual field progression

BACKGROUND AND OBJECTIVE

To evaluate the ability of structural assessment to predict glaucomatous visual field progression.

PATIENTS AND METHODS

A total of 119 healthy eyes with suspected glaucoma and glaucomatous eyes with 5 or more optic nerve stereophotographs, optical coherence tomography (OCT), and confocal scanning laser ophthalmoscopy (CSLO) all acquired within 6 months of each other were enrolled. Odds ratios to predict progression were determined by generalized estimating equation models.

RESULTS

Median follow-up was 4.0 years (range: 1.5 to 5.7 years). Fifteen eyes progressed by glaucoma progression analysis, 20 by visual field index, and 10 by both. Baseline parameters from stereophotographs (vertical cup-to-disc ratio and Disc Damage Likelihood Scale), OCT (global, superior quadrant, and inferior quadrant retinal nerve fiber layer thickness), and CSLO (cup shape measure and mean cup depth) were significant predictors of progression. Comparing the single best parameter from all models, only the OCT superior quadrant RNFL predicted progression.

CONCLUSION

Baseline stereophotographs, OCT, and CSLO measurements may be clinically useful to predict glaucomatous visual field progression.