Tear nanoDSF Denaturation Profile Is Predictive of Glaucoma

Primary open-angle glaucoma (POAG) is a frequent blindness-causing neurodegenerative disorder characterized by optic nerve and retinal ganglion cell damage most commonly due to a chronic increase in intraocular pressure. The preservation of visual function in patients critically depends on the timeliness of detection and treatment of the disease, which is challenging due to its asymptomatic course at early stages and lack of objective diagnostic approaches. Recent studies revealed that the pathophysiology of glaucoma includes complex metabolomic and proteomic alterations in the eye liquids, including tear fluid (TF). Although TF can be collected by a non-invasive procedure and may serve as a source of the appropriate biomarkers, its multi-omics analysis is technically sophisticated and unsuitable for clinical practice. In this study, we tested a novel concept of glaucoma diagnostics based on the rapid high-performance analysis of the TF proteome by differential scanning fluorimetry (nanoDSF). An examination of the thermal denaturation of TF proteins in a cohort of 311 ophthalmic patients revealed typical profiles, with two peaks exhibiting characteristic shifts in POAG. Clustering of the profiles according to peaks maxima allowed us to identify glaucoma in 70% of cases, while the employment of artificial intelligence (machine learning) algorithms reduced the amount of false-positive diagnoses to 13.5%. The POAG-associated alterations in the core TF proteins included an increase in the concentration of serum albumin, accompanied by a decrease in lysozyme C, lipocalin-1, and lactotransferrin contents. Unexpectedly, these changes were not the only factor affecting the observed denaturation profile shifts, which considerably depended on the presence of low-molecular-weight ligands of tear proteins, such as fatty acids and iron. Overall, we recognized the TF denaturation profile as a novel biomarker of glaucoma, which integrates proteomic, lipidomic, and metallomic alterations in tears, and monitoring of which could be adapted for rapid non-invasive screening of the disease in a clinical setting.

[Experimental simulation for determining optimal design parameters of a transpalpebral tonometry sensor]

PURPOSE

To determine optimal design parameters of a transpalpebral tonometry sensor (the weight and diameter of the rod) based on experimental simulation.

MATERIAL AND METHODS

The study has been conducted in situ at the forensic analysis department with 12 eyes of 5 men and one woman aged 49 to 71 years. Comparison between the tonometric pressure and the true pressure measured with direct manometric technique ensured the accuracy of transpalpebral tonometry data and helped select optimal sensor parameters. For this purpose, an experimental assembly was designed and produced, comprised of a testing stand with a system of tubes filled with distilled water, an indicating pressure gauge calibrated by the height of the water column, a millimeter scale on a holder, as well as a needle with connecting tubes and two valves.

RESULTS

No statistically significant differences between the tonometric and manometric level of pressure in the eye were observed when using a sensor weighing 16 g with rod diameter of 1.5 or 3 mm. Only an insignificant dependence of the tonometry data on the thickness of the eyelid was noted at high levels of intraocular pressure (IOP).

CONCLUSION

The experimental study conducted on the developed assembly has allowed us to substantiate the choice of optimal design parameter for a transpalpebral IOP measurement sensor. A transpalpebral tonometer with such sensor characteristics can be recommended for comparative clinical study, as well as for determination of its effectiveness in dynamical monitoring of the IOP levels.

[Evaluation of various methods effectiveness for aphakia correction in patients with myopic refraction and glaucoma]

The efficiency of various methods for correcting postoperative aphakia was evaluated in 113 patients (118 eyes) with medium and high myopia and glaucoma. In group 1 (44 eyes) extraocular correction of aphakia was planned after cataract extraction, in group 2 (33 eyes) intraocular lenses were implanted, in group 3 (21 eyes) combined interventions were performed (cataract extraction with antiglaucoma component), and in group 4 (20 eyes) cataract extraction was performed simultaneously with sinusotrabeculectomy and intraocular correction of aphakia. The number of patients with visual acuity higher than 0.1 was significantly more in groups 2 and 4 after implantation of intraocular lenses than in groups 1 and 3, who needed extraocular correction of aphakia: 59.1% in group 1, 42.9% in group 3, 78.8% in group 2, and 60% in group 4. Intraocular correction of aphakia in patients with glaucoma and myopia helps attain the maximum possible visual acuity even in patients with far-advanced stages of the disease with residual visual field. Individual approach to estimation of optic force of implanted intraocular lens helps reduce the myopic refraction of the operated eye.

[Therapy of patients with primary open-angle glaucoma with proxofelin, a combined form of proxodolol]

Effects of an original Russian combined preparation proxofelin consisting of 1% proxodolol and 0.25% clofelin solutions on intraocular pressure, ocular hemodynamics, pupil size, depth of the anterior chamber, ocular functions, arterial pressure, and heart rate were studied in 59 patients (80 eyes) with primary open-angle glaucoma. The studies were carried out on day 1 after a single instillation of the drug and after 4-8 weeks of its regular use. Obvious hypotensive effect on intraocular pressure is due to a significant increase of the discharge efficacy coefficient (by 0.06 +/- 0.008) and a 40% suppression of aqueous humor production. Comparison of the efficacies of proxofelin and proxodolol in primary open-angle glaucoma showed the advantages of the combined drug. Unlike cloefelin, the drug was well tolerated.

[Use of Naclof in combined intervention for cataract and glaucoma]

Two aspects of using eye drops of a nonsteroid antiinflammatory drug Naclof (sodium diclofenac) are analyzed: maintenance of mydriasis during an intervention (extracapsular cataract extraction with implantation of an intraocular lens and trabeculectomy and arrest of postoperative inflammation. The study was carried out in 40 patients, 20 of which were controls. In the naclof group the diameter of the pupil during the intervention was reliably larger, exudative inflammatory reactions were rarer, and the postoperative vision acuity higher. Hence, naclof is effective in combined interventions for cataract and glaucoma.