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Correction of induced corneal topographic changes in patients after bleb-dependent fistulizing surgery

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First Author: N.Volkova RUSSIA

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To study the types (progressive, regressive, stable) of induced optical aberrations after fistulizing surgeries and the efficacy of their correction by phacoemulsification with implantation of toric IOL.


Irreversible induced changes in corneal topography after fistulizing operations, despite their positive hypotensive effect, occur in 12.8% and reduce both uncorrected and corrected visual acuity and quality of life.


163 people (175 eyes) aged 54.2±5.3 years with open-angle glaucoma were examined before, on the 5th day, 1, 3, 6 and 12 months after trabeculectomy. The optical corneal properties were studied using optical biometry, keratotomography (Pentacam, Oculus) using the programs Refractive, Holladay ECR Detail Report, and Fourier-Analysis. An OCT study of meniscusmetry and epithelium map (OCT RTV 100/CA, Optovie) was conducted. When planning phacoemulsification with toric IOL implantation (n = 9), IOL-Master was used to calculate the spherical component, the degree and axis of astigmatism were calculated in an on-line calculator.


Dispersion of aberrations of the highest order: spherical (p = 0.053), coma vertical (p=0.0017), coma horizontal (p=0.0014), trefoil (p=0.00026) were reversible. Lower-order aberrations - irregular astigmatism (spherical component (+) 1.75±3.5 D, cylindrical (-) 4.5±2.61 D) cause persistent decrease in visual acuity (p=0.001). In these cases, patients underwent phacoemulsification with toric IOL implantation, which allowed them to achieve stable refractive effect. Residual astigmatism was 0.69±0.17 D with achieving maximum possible "visual axis clarity" (p=0.001). The instability of the tear film and the height of the tear meniscus also had clinically significant changes (p=0.001) and required the appointment of tear lubricants.


Fistulizing operations induce changes in cornea topography and the pre-corneal tear film. In the presence of persistent irregular astigmatism, the presented approach (phacoemulsification with toric IOL implantation) to the choice of correction of induced changes is a highly effective and safe way to restore the clarity of the visual axis and preserve the hypotensive effect of the fistulizing operation.

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