Optic nerve head parameters of high‑definition optical coherence tomography and Heidelberg retina tomogram in perimetric and preperimetric glaucoma.

Background: Heidelberg retina tomogram (HRT) and optical coherence tomography (OCT) are two widely used imaging modalities to evaluate the optic nerve head (ONH) in glaucoma. Purpose: To compare the ONH parameters of HRT3 and high‑definition OCT (HD‑OCT) and evaluate their diagnostic abilities in perimetric and preperimetric glaucoma. Design: Cross‑sectional analysis. Methods: 35 control eyes (24 subjects), 21 preperimetric glaucoma eyes (15 patients), and 64 perimetric glaucoma eyes (44 patients) from the Longitudinal Glaucoma Evaluation Study underwent HRT3 and HD‑OCT examinations. Statistical Analysis: Agreement between the ONH parameters of HRT and HD‑OCT were assessed using Bland–Altman plots. Diagnostic abilities of ONH parameters were evaluated using area under the receiver operating characteristic curves (AUCs), sensitivity at fixed specificity, and likelihood ratios (LR). Results: Optic disc area, vertical cup to disc ratio, and cup volume with HD‑OCT were larger than with HRT, while the rim area was smaller with HD‑OCT (P < 0.001 for all comparisons). AUCs of all HD‑OCT ONH parameters (0.90–0.97 in perimetric and 0.62–0.71 in preperimetric glaucoma) were comparable (P > 0.10) to the corresponding HRT ONH parameters (0.81–0.95 in perimetric and 0.55–0.72 in preperimetric glaucoma). LRs associated with diagnostic categorization of ONH parameters of both HD‑OCT and HRT were associated with larger effects on posttest probability of perimetric compared to preperimetric glaucoma. Conclusions: ONH measurements of HD‑OCT and HRT3 cannot be used interchangeably. Though the diagnostic abilities of ONH parameters of HD‑OCT and HRT in glaucoma were comparable, the same were significantly lower in preperimetric compared to perimetric glaucoma.

Evidence-based approach to glaucoma management.

Evidence-based medicine is an evolving new paradigm. With the advent of numerous new diagnostic techniques and therapeutic interventions, one needs to critically evaluate and validate them by appropriate methods before adopting them into day-to-day patient care. The concepts involved in the evaluation of diagnostic tests and therapy are discussed. For delivering the highest level of clinical care, evidence alone is not sufficient. Integrating individual clinical experience and patients’ perspectives with the best available external evidence is essential.