Detecting glaucoma with only OCT: Implications for the clinic, research, screening, and AI development.

A method for detecting glaucoma based only on optical coherence tomography (OCT) is of potential value for routine clinical decisions, for inclusion criteria for research studies and trials, for large-scale clinical screening, as well as for the development of artificial intelligence (AI) decision models. Recent work suggests that the OCT probability (p-) maps, also known as deviation maps, can play a key role in an OCT-based method. However, artifacts seen on the p-maps of healthy control eyes can resemble patterns of damage due to glaucoma.

Relationship between optic disc hemorrhage and corneal hysteresis.

Objective: To determine the relationship between optic disc hemorrhage (DH) and corneal hysteresis (CH).

Methods: Consecutive patients with prior or current photographic evidence of unilateral DH who had undergone CH measurement with the Ocular Response Analyzer (ORA; Reichert, Buffalo, NY) were enrolled. Eyes with a history of corneal disease, refractive surgery, or bilateral DH were excluded.

Qualitative evaluation of neuroretinal rim and retinal nerve fibre layer on optical coherence tomography to detect glaucomatous damage.

Purpose: To understand the added value of Bruch's membrane opening-minimum rim width (BMO-MRW) measurements to conventional circumpapillary retinal nerve fibre layer (cpRNFL) thickness measurements on optical coherence tomography (OCT) imaging for discriminating between perimetric glaucoma and healthy eyes, evaluated through a qualitative evaluation.

Methods: 384 healthy eyes and 188 glaucoma eyes were evaluated, and glaucoma eyes were categorised as perimetric (n=107) based on a history of ≥3 consecutive abnormal 24-2 visual field tests or suspected glaucoma if they did not (n=81). OCT-derived BMO-MRW and cpRNFL reports were qualitatively evaluated by two experienced graders in isolation at first, and then by using both reports combined.

Improving glaucoma detection using spatially correspondent clusters of damage and by combining standard automated perimetry and optical coherence tomography.

Purpose: To improve the detection of glaucoma, techniques for assessing local patterns of damage and for combining structure and function were developed.

Methods: Standard automated perimetry (SAP) and frequency-domain optical coherence tomography (fdOCT) data, consisting of macular retinal ganglion cell plus inner plexiform layer (mRGCPL) as well as macular and optic disc retinal nerve fiber layer (mRNFL and dRNFL) thicknesses, were collected from 52 eyes of 52 healthy controls and 156 eyes of 96 glaucoma suspects and patients. In addition to generating simple global metrics, SAP and fdOCT data were searched for contiguous clusters of abnormal points and converted to a continuous metric (pcc).

The Nature of Macular Damage in Glaucoma as Revealed by Averaging Optical Coherence Tomography Data.

Purpose: To better understand the nature of glaucomatous damage, especially to the macula, the inner retinal thickness maps obtained with frequency domain optical coherence tomography (fdOCT) were averaged.

Methods: Frequency domain optical coherence tomography macular and optic disc cube scans were obtained from 54 healthy eyes and 156 eyes with glaucomatous optic neuropathy. A manually corrected algorithm was used for layer segmentation.

Is preoperative ciliary body and iris anatomical configuration a predictor of malignant glaucoma development?

Background: To investigate anatomical configuration of ciliary body and iris using ultrasound biomicroscopy as a predictor of malignant glaucoma development.

Design: Retrospective study in a tertiary care hospital.

Participants: Cohort of 31 consecutive patients diagnosed with post-surgical malignant glaucoma.

Glaucomatous damage of the macula.

There is a growing body of evidence that early glaucomatous damage involves the macula. The anatomical basis of this damage can be studied using frequency domain optical coherence tomography (fdOCT), by which the local thickness of the retinal nerve fiber layer (RNFL) and local retinal ganglion cell plus inner plexiform (RGC+) layer can be measured. Based upon averaged fdOCT results from healthy controls and patients, we show that: 1.

Understanding disparities among diagnostic technologies in glaucoma.

Objective: To investigate causes of disagreement among 3 glaucoma diagnostic techniques: standard automated achromatic perimetry (SAP), the multifocal visual evoked potential technique (mfVEP), and optical coherence tomography (OCT).

Methods: In a prospective cross-sectional study, 138 eyes of 69 patients with glaucomatous optic neuropathy were tested using SAP, the mfVEP, and OCT. Eyes with the worse and better mean deviations (MDs) were analyzed separately.

Retinal ganglion cell layer thickness and local visual field sensitivity in glaucoma.

Objective: To compare loss in sensitivity measured using standard automated perimetry (SAP) with local retinal ganglion cell layer (RGC) thickness measured using frequency-domain optical coherence tomography in the macula of patients with glaucoma.

Methods: To compare corresponding locations of RGC thickness with total deviation (TD) of 10-2 SAP for 14 patients with glaucoma and 19 controls, an experienced operator hand-corrected automatic segmentation of the combined RGC and inner plexiform layer (RGC+IPL) of 128 horizontal B-scans. To account for displacement of the RGC bodies around the fovea, the location of the SAP test points was adjusted to correspond to the location of the RGC bodies rather than to the photoreceptors, based on published histological findings.

The rate of visual field change in the ocular hypertension treatment study.

Purpose: To assess the rate of change of visual field (VF) mean deviation (MD) in the Ocular Hypertension Treatment Study (OHTS).

Methods: OHTS data were filtered to exclude eyes that had fewer than 10 reliable VFs or less than 5 years of follow-up or that reached a nonglaucomatous endpoint. The rate of change of MD (MDR) was calculated for each eye.

Enhanced depth imaging optical coherence tomography of deep optic nerve complex structures in glaucoma.

Objective: To assess the usefulness of enhanced depth imaging (EDI) optical coherence tomography (OCT) for evaluating deep structures of the optic nerve complex (ONC; optic nerve head and peripapillary structures) in glaucoma.

Design: Prospective, observational study.

Participants: Seventy-three established glaucoma patients (139 eyes) with a range of glaucomatous damage.

Short-duration transient visual evoked potential for objective measurement of refractive errors.

This study examined effects of uncorrected refractive errors (RE) in a short-duration transient visual evoked potential (SD t-VEP) system and investigated their role for objective measurement of RE. Refractive errors were induced by means of trial lenses in 35 emmetropic subjects. A synchronized single-channel EEG was recorded for emmetropia, and each simulated refractive state to generate 21 VEP responses for each subject.

Hypodense regions (holes) in the retinal nerve fiber layer in frequency-domain OCT scans of glaucoma patients and suspects.

Purpose: To better understand hypodense regions (holes) that appear in the retinal nerve fiber layer (RNFL) of frequency-domain optical coherence tomography (fdOCT) scans of patients with glaucoma and glaucoma suspects.

Methods: Peripapillary circle (1.7-mm radius) and cube optic disc fdOCT scans were obtained on 208 eyes from 110 patients (57.

Short duration transient visual evoked potentials in glaucomatous eyes.

Purpose: To investigate the correlation between structural and functional damage in patients with asymmetric glaucoma using a newly developed short duration transient visual evoked potential (SD-tVEP) device.

Methods: Twenty-five patients with visual acuity ≥20/30 and asymmetric visual field (VF) loss [inter-eye difference in mean deviation index (MD) of at least 3 dB] were enrolled. Patients underwent optical coherence tomography (OCT) for macular thickness measurement, scanning laser polarimetry with variable corneal compensation for retinal nerve fiber layer measurement, and SD-tVEP (10% and 85% Michelson contrast, acquisition time of 20 s) in both eyes within 2 months.

Risk factors for visual field progression in treated glaucoma.

Objective: To determine intraocular pressure (IOP)-dependent and IOP-independent variables associated with visual field (VF) progression in treated glaucoma.

Design: Retrospective cohort of the Glaucoma Progression Study.

Methods: Consecutive, treated glaucoma patients with repeatable VF loss who had 8 or more VF examinations of either eye, using the Swedish Interactive Threshold Algorithm (24-2 SITA-Standard, Humphrey Field Analyzer II; Carl Zeiss Meditec, Inc, Dublin, California), during the period between January 1999 and September 2009 were included.

Initial arcuate defects within the central 10 degrees in glaucoma.

Purpose: To better understand the relationship between the spatial patterns of functional (visual field [VF] loss) and structural (axon loss) abnormalities in patients with glaucomatous arcuate defects largely confined to the central 10° on achromatic perimetry.

Methods: Eleven eyes (9 patients) with arcuate glaucomatous VF defects largely confined to the macula were selected from a larger group of patients with both 10-2 and 24-2 VF tests. Eyes were included if their 10-2 VF had an arcuate defect and if the 24-2 test was normal outside the central 10° (i.

Posture-induced intraocular pressure changes: considerations regarding body position in glaucoma patients.

Although glaucoma is a multifactorial disease, elevated intraocular pressure (IOP) remains the most important known risk factor. Different systemic and local factors are thought to influence an individual's IOP. There can be a clinically significant rise in IOP when going from upright to horizontal or inverted body positions.

In-vivo microstructural anatomy of beta-zone parapapillary atrophy in glaucoma.

Purpose: To assess the microstructural anatomy of clinical β-zone parapapillary atrophy (βPPA) by using Fourier-domain optical coherence tomography (FD-OCT).

Methods: Color photographs and horizontal cross-sectional FD-OCT images of the optic disc and parapapillary retina were obtained in 24 eyes (24 patients with glaucoma or suspected glaucoma) with βPPA. The distances between the temporal disc margin and parapapillary landmarks (clinical βPPA margin and the edges of the retinal pigment epithelium [RPE], Bruch's membrane [BM], and the photoreceptor inner/outer segment [IS/OS] junction) were measured in 5 equally spaced horizontal meridians (total, 120 meridians).

Corneal hysteresis and visual field asymmetry in open angle glaucoma.

Purpose: To investigate the association between corneal biomechanical parameters and asymmetric primary open angle glaucoma (POAG) using the Ocular Response Analyzer (ORA).

Methods: In a prospective cross-sectional study, ORA parameters were measured in 117 POAG patients with asymmetric visual fields (VF). The asymmetry in VF was defined as a five point difference between the eyes using the Advanced Glaucoma Intervention Study (AGIS) scoring system.

Modified visual field trend analysis.

Purpose: Visual field trend analysis can be influenced by outlying values that may disproportionately affect estimation of the rate of change. We tested a modified approach to visual field trend analysis to minimize this problem.

Methods: Automated pointwise linear regression (PLR) was used in glaucoma patients with ≥13 SITA-Standard 24-2 VF tests in either eye.

Recurrent disc hemorrhage does not increase the rate of visual field progression.

Aims: To determine whether recurrent disc hemorrhage (DH) accelerates glaucomatous visual field (VF) loss compared to an isolated, single, detected DH.

Methods: We evaluated the disc photographs of consecutive patients with >/=5 SITA-Standard fields for DH. Group A had patients with a single DH in one eye, and group B had at least one recurrence in the same eye.

Beta-Zone parapapillary atrophy and the velocity of glaucoma progression.

Purpose: Beta-Zone parapapillary atrophy (PPA) occurs more commonly in eyes with glaucoma. Rates of glaucomatous visual field (VF) progression in eyes with and without beta-zone PPA at the time of baseline assessment were compared.

Design: Retrospective, comparative study.