[Optical coherence tomography and optical coherence tomography angiography for detecting glaucoma progression. Part 2. Clinical and functional correlations, monitoring of advanced glaucoma and limitations of the method]

The purpose of this study is to analyze the literature on the role of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in the diagnosis of glaucoma. This review considers the structural and functional correlations observed during the progression of glaucomatous optic neuropathy, as well as the capabilities of the method in late glaucoma, describes the strengths and weaknesses of OCT and OCTA, and pays particular attention to the role of OCT in assessing the effectiveness of treatment. Optical coherence tomography is the main method for determining the progression of glaucoma, which plays a key role in the choice of treatment algorithm. However, the use of OCT in far advanced glaucoma has certain particularities and limitations. OCTA can be helpful in overcoming this problem.

The “Topography” of Glaucomatous Defect Using OCT and Visual Field Examination

Aim

To describe the modifications in the superior and inferior retinal nerve fiber layer (RNFL) thickness regarding the distribution of the VF defects for the horizontal meridians in glaucomatous patients and the differences in the RNFL thickness topography between glaucomatous and healthy subjects.

Methods

One hundred twenty eyes of 91 patients affected by glaucoma and 94 eyes of 51 normal patients were retrospectively reviewed. Computerized 30°VF (Octopus G1 Dynamic strategy) and optical coherence tomography (OCT) ONH and 3D disk analysis were performed in all cases. The RNFL thickness measures analyzed in both groups were superior-nasal (SN), superior-temporal (ST), inferior-nasal (IN), and inferior temporal (IT) sectors. The VFs were classified according to the distribution of the VF defect as for the horizontal meridian in the pattern deviation plot as superior, inferior, predominantly superior, or predominantly inferior.

Result

In the glaucomatous group, 78 eyes (65%) showed a predominantly superior VF defect, while 38 eyes (32%) showed a predominantly inferior VF defect. Fifty-six eyes (46.7%) presented an exclusively superior, and 27/120 eyes (22.5%) presented an exclusively inferior VF defect. In the control group, the thickest RNFL sector was IT. The ST sector showed the thickest RNFL in presence of an exclusive superior VF defect. In case of an exclusive inferior VF defect, the thickest RNFL was the IT sector. VF showing superior defect presented a more altered MD than the VF with an inferior defect.

Conclusion

Glaucomatous damage affects both the superior and inferior neural rim almost simultaneously. However, the neural rim loss seems to be asymmetric, involving the inferior or superior rim depending on the predominant involvement of the superior or inferior hemifield at the VF test. Particularly, the IT sector appears to be the most compromised in glaucomatous eyes. Therefore, the asymmetry between superior and inferior RNFL could support the diagnosis of glaucoma.

How to cite this article

de Paula A, Perdicchi A, Pocobelli A, et al. The “Topography” of Glaucomatous Defect Using OCT and Visual Field Examination. J Curr Glaucoma Pract 2022;16(1):31-35.

The different structure-function correlation as measured by OCT and octopus perimetry cluster analysis in intracranial tumor and glaucoma patients

BACKGROUND

To explore the correlation between visual field (VF) defect values and retinal nerve fiber layer (RNFL) thickness for intracranial tumor and glaucoma patients.

METHODS

Retrospective analysis is performed for the intracranial and glaucoma patients, whose VF defect values were measured with Octopus perimeter cluster analysis, RNFL thickness, ganglion cell layer (GCL) thickness, and optic disk parameters measured with swept-source OCT. The differences between VF and RNFL (including the data of optic disc) are calculated. The correlation between VF defect values and RNFL and GCL thickness are explored.

RESULTS

In total 43 eyes of 29 patients with intracranial tumor and 31 eyes of 19 patients with glaucoma were enrolled. The thickness of RNFL not only for the whole (360°), but also for the four quadrants was thinner in the glaucoma group than those of the intracranial tumor group (p<0.05), and similar to the thickness of GCL without significance (p>). There is no significant difference in VF for those two groups except glaucoma having lower sLV (p<0.05). A stronger correlation for mean deviations (MD)s of VF ten clusters and RNFL thickness of OCT twelve sectors is found in the glaucoma patients, but few in the intracranial tumor patients. Logistic regression also shows the loss of RNFL or increasing of vertical CDR and cup volume tending to the diagnosis of glaucoma and the irregular VF damage is inclined to the diagnosis of intracranial tumor.

CONCLUSIONS

Intracranial tumor has a weak correlation between the RNFL thickness and Octopus VF MD, compared with that of glaucoma. OCT and Octopus VF might provide more helpful information for the differential diagnosis of intracranial tumor and glaucoma.

Effect of intraocular pressure lowering on the capillary density of optic nerve head and retinal nerve fiber layer in patients with glaucoma

Purpose:

To evaluate the effect of IOP lowering on the capillary density of optic nerve head and retinal nerve fiber layer in patients with primary open angle glaucoma.

Methods:

Twenty eyes of 14 glaucomatous patients and 15 eyes of nine normal patients were enrolled. The most appropriate hypotonic treatment was applied to every patient. A HD Angio Disc 4.5 scan (Avanti-AngioVue) was performed at baseline and after a month in the glaucomatous eyes. The following parameters were analyzed: Radial Papillary Capillaries (RPC) density, inside disc, peripapillary, superior-hemi, inferior-hemi, quadrants, and peripapillary, hemi-superior, hemi-inferior, and quadrants RNFL thickness. Optic nerve head analysis was also evaluated. In addition, the RPC density and the RNFL were assessed in the eight sectors provided by the software.

Results:

The RPC density did not significantly change after IOP reduction ( p > 0.05). The inferior-temporal ( p = 0.005) and inferior-nasal sectors ( p < 0.001) showed a greater capillary density than the respective superior sectors in healthy eyes. In contrast in the glaucomatous eyes, the superior-nasal exhibited greater capillary density with respect to the inferior-nasal sectors. The aggregate RPC density of the inferior sectors was greater than the superior ones in the control group ( p < 0.001). An improvement of the average disc area ( p = 0.01) and the average cup volume ( p = 0.059) were also observed along with increased RNFL thickness at different locations (all, p < 0.05) after IOP lowering therapy was initiated.

Conclusion:

The glaucomatous eyes presented rarefaction of the radial papillary capillaries density in the inferior sectors, but no significant changes in the density after IOP-lowering medications.

Ocular manifestations in phakomatosis pigmentovascularis: Current concepts on pathogenesis, diagnosis, and management

Phakomatosis pigmentovascularis is a rare congenital multisystemic disease with variable manifestations where a vascular malformation of the skin is associated with a pigmentary nevus. Ocular involvement includes glaucoma, choroidal hemangioma, and pigmentary alterations that predispose to uveal melanoma. Diagnosis is made on clinical grounds, although recent advances in molecular genetics have better clarified the etiopathogenesis of the condition. The advent of improved imaging techniques such as enhanced depth imaging spectral domain optical coherence tomography has provided new insight into the ocular alterations, enabling better follow-up of patients. We review the ophthalmic manifestations of the disease with an update on etiopathogenesis and current management strategies.

An Iconic Case of Pigmentary Glaucoma: Brief Review of the Literature

Pigment dispersion syndrome and pigmentary glaucoma are two conditions characterized by pigment dispersion originating from the posterior part of the iris and its accumulation on the trabecular meshwork, corneal endothelium, and anterior surface of the lens. The pigment on the trabecular meshwork can cause chronic inflammation with a secondary reduction of its function and an increase in intraocular pressure. The case presented represents a typical example of pigmentary glaucoma in a myopic patient in which all the signs, symptoms, and complications typical of these pathologies were present. We report and describe an 8-year-long follow-up period with clinical and instrumental examinations.

Ganglion Cell Complex Analysis in Glaucoma Patients: What Can It Tell Us?

Glaucoma is a group of optic neuropathies characterized by a progressive degeneration of retina ganglion cells (RGCs) and their axons that precedes functional changes detected on the visual field. The macular ganglion cell complex (GCC), available in commercial Fourier-domain optical coherence tomography, allows the quantification of the innermost retinal layers that are potentially involved in the glaucomatous damage, including the retinal nerve fiber (RNFL), ganglion cell and inner plexiform layers. The average GCC thickness and its related parameters represent a reliable biomarker in detecting preperimetric glaucomatous damage. The most accurate GCC parameters are represented by average and inferior GCC thicknesses, and they can be associated with progressive visual field loss. Although the diagnostic accuracy increases with more severe glaucomatous damage and higher signal strength values, it is not affected by increasing axial length, resulting in a more accurate discrimination of glaucomatous damage in myopic eyes with respect to the traditional RNFL thickness. The analysis of the structure-function relationship revealed a good agreement between the loss in retinal sensitivity and GCC thickness. The use of a 10-2° visual field grid, adjusted for the anatomical RGCs displacement, describes more accurately the relationship between RGCs thickness and visual field sensitivity loss.