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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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Abstract Details

Purpose:

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.

Setting:

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.

Methods:

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.

Results:

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.

Conclusions:

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.

Financial Disclosure:

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