Optic nerve head hemoglobin measurements help in early diagnosis of primary open angle glaucoma: Study

In a new study published in Glaucoma, it was seen that using measurements of optic nerve head (ONH) hemoglobin concentrations, the Laguna ONhE program may offer a reliable and affordable method of identifying early primary open angle glaucoma (POAG).

The Laguna ONhE, a program that analyses fundus photos to determine the hemoglobin (Hb) content of the optic nerve head, showed high accuracy in differentiating between healthy and eyes with moderate glaucoma. In order to differentiate between healthy eyes and eyes with moderate glaucoma, Livia Studart de Meneses and colleagues conducted this investigation with the goal of measuring the Hb content of the optic nerve.

For this study, both healthy volunteers (n=64) and patients with mild primary open angle glaucoma (MD > 6 dB) had their eyes chosen. All eyes' retinal nerve fiber layer thicknesses were measured using optical coherence tomography. Additionally, optic disc pictures were acquired, and the images were examined using the Laguna ONhE program, which calculates the quantity of Hb in 24 ONH sectors. The Glaucoma Discriminant Function (GDF), an index that quantifies the likelihood that the ONH is consistent with glaucoma, is also computed by the program. Each Laguna ONhE parameter's areas under the receiver operating characteristic curve and sensitivities at preset specificities of 90% and 95% were computed.

The key findings of this study were as follows:

1. The mean nerve fiber of retinal layer thickness and vertical cup/disc ratio of the two given groups, control and glaucoma were 90.0±10.6 m and 66.28±9.85 m, respectively, and 0.5±0.09 vs 0.65±0.09.

2. Total Hb was considerably greater in the control group (67.9±4.45 vs. 62.89±4.89, P0.001), as was GDF (11.57±15.34 vs. 27.67±20.94, P0.001).

3. The Hb concentration in the control group was likewise substantially greater in 21 of the 24 sectors compared to the glaucoma group (P0.05).

4. The GDF exhibited the greatest area under the receiver operating characteristic curve (0.93), with 79.3% sensitivity and 95% fixed specificity.

In conclusion, analyses of optic nerve Hb content using a colorimetry photographic instrument indicated strong discrimination between healthy and moderate glaucoma eyes. More research is needed to understand the vascular variables involved in the development of glaucoma.

Reference: 

Meneses, L. S. de, Ciarlini, L. R., Ayub, G., Vasconcellos, J. P. C., & Costa, V. P. (2022). Discrimination Between Healthy Eyes and Those With Mild Glaucoma Damage Using Hemoglobin Measurements of the Optic Nerve Head. In Journal of Glaucoma (Vol. 31, Issue 7, pp. 567–573). Ovid Technologies (Wolters Kluwer Health). https://doi.org/10.1097/ijg.0000000000002026