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Quality factor based correction for SD-OCT measurements in cataract patients.
Stanley Darma1, Thomas J T P van den Berg2, Pauline H B Kok1
1Department of Ophthalmology, Amsterdam UMC, Amsterdam, the Netherlands.
Acta Ophthalmologica
|June 19, 2019
Summary
Cataract significantly impacts peripapillary retinal nerve fibre layer (pRNFL) measurements using spectral domain optical coherence tomography (SD-OCT), leading to underestimation at lower image quality factors (QF). Corrected pRNFL measurements still showed differences post-surgery.
Area of Science:
- Ophthalmology
- Medical Imaging
- Retinal Diagnostics
Background:
- Cataracts can degrade image quality in optical coherence tomography (OCT) scans.
- Accurate peripapillary retinal nerve fibre layer (pRNFL) measurements are crucial for diagnosing glaucoma.
- Spectral domain optical coherence tomography (SD-OCT) is a standard tool for pRNFL assessment.
Purpose of the Study:
- To develop a correction method for pRNFL measurements affected by cataract-induced low image quality.
- To validate the correction using pre- and post-cataract surgery SD-OCT data.
- To quantify the impact of image quality factor (QF) on pRNFL thickness measurements.
Main Methods:
- Utilized SD-OCT volume scans of the optic disc from 13 cataract patients.
- Analyzed changes in pRNFL thickness and image QF before and after cataract surgery.
- Formulated a correction equation based on the correlation between pRNFL thickness and QF.
Main Results:
- pRNFL thickness measurements differed significantly before (96 microns) and after (99 microns) cataract surgery (p < 0.01).
- Preoperative and postoperative linear regression slopes for pRNFL thickness varied.
- Corrected pRNFL measurements from eyes with cataracts showed significant differences compared to post-surgery measurements.
Conclusions:
- Cataract presence significantly alters the relationship between image QF and pRNFL measurements.
- Lower image QF leads to underestimation of pRNFL thickness.
- Even corrected pRNFL measurements in the presence of cataracts remained significantly different from post-surgery measurements, indicating residual effects.
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