Офтальмохирургия (Jul 2016)

Acoustic changes of sclera in case of primary open-angle glaucoma

  • E. V. Egorova,
  • D. G. Uzunyan,
  • A. V. Milingert

DOI
https://doi.org/10.25276/0235-4160-2016-2-22-27
Journal volume & issue
Vol. 0, no. 2
pp. 22 – 27

Abstract

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Purpose. To study the acoustic density (ADS) and the thickness of the sclera in patients with primary open-angle glaucoma (POAG) taking into account the stage the glaucoma process and refraction.Material and methods. The study involved in 273 eyes of 138 examined patients with the POAG of stage 1-3. The mean age was 66±4, the IOP – 21±4mmHg in the hypotensive mode, the axial length of the eye – 23.56±2.31. The comparative group included 90 eyes of 45 patients aged 65±6.5 years without the diagnosed glaucoma, the IOP was 20±3mmHg. All patients underwent the ultrasound bio-microscopy (UBM). Scanning the thickness of sclera was performed in the limbus area and 4mm from the scleral spur in 4 segments at the 3,6,9,12 o’clock positions. The ADS determination was carried out in dB by a reduction of the power of ultrasound to the disappearance of echoes from scleral capsule of the eye on the scr een.Results. The sclera of the eyes was not uniform in its thickness in different zones of measurement. The maximum thickness of the sclera was detected in the limbus area at the 9 o’clock position in the comparative group and was 0.63±0.02mm; the smallest thickness was detected in patients with myopia at the 12 o’clock position and was 0.51±0.04mm. Thinning of the sclera in the equatorial zone was significantly (p<0.05) more pronounced in glaucoma eyes and achieved 0.23±0.01mm in patients with emmetropia, 0.21±0.01mm – in myopia, 0.25±0.01mm – in hyperopia. Significant (p<0.001) ADS changes in all studied segments were determined in patients with the first and third stages of glaucoma and were 56±0.74 dB and 62dB±0.58 in patients with emmetropia; 56±0.67dB and 60±0.71dB – in myopia; 60±0.43dB and 63±0.57dB – in hyperopia, respectively. Conclusion. A gradual reduction of the thickness of sclera and an ADS increase reflects an involvement of the sclera into a pathologic glaucoma process what can indicate a change in its biomechanical properties. The most pronounced acoustic changes of sclera are detected in individuals with myopic type of refraction that is caused by morphologic changes of fibrous tunica of the eye at fir st.

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