ZHENG Feihui Freya
- MPhil, Ophthalmology, The University of Hong Kong
- BMed, Medicine, Sun Yat-sen University
- OCT rim width measurement in glaucoma and myopic eyes
- Anterior chamber angle measurement with a new swept-source OCT
(1) OCT rim width measurement in glaucoma and myopic eyes
Narrowing of the neuroretinal rim and thinning of the retinal nerve fiber layer (RNFL) are two key features of glaucoma. Measurement of these parameters, however, can be challenging in eyes with myopia. In this study, we compared the diagnostic performance of the minimum rim width (MRW) and topographical RNFL thickness measurements obtained with the spectral-domain optical coherence tomography for detection of glaucoma in high myopic eyes (spherical error <-6.0D). We hypothesize that topographical analysis of the RNFL would outperform MRW measurements as the presence of parapapillary atrophy (gamma and beta) may compound the measurement of MRW.
Figure 1. The Bruch’s membrane opening (BMO), identified with optical coherence tomogrpahy, has been shown to be a reliable anatomical landmark of the disc margin. The minimum rim width (MRW) is measured from the BMO to the nearest point at the internal limiting membrane (ILM).
(2) Angle measurement with a new swept-source OCT
Anterior chamber angle measurement is important for the detection of angle closure. Using a new swept-source anterior segment OCT (AS-OCT) (CASIA2, Tomey, Nagoya, Japan), the anterior segment can be imaged for 360O three dimensionally. We have developed a new algorithm (STAR – Scleral spur Tracking for Angle analysis and Registration) for anterior chamber angle measurements and demonstrated high reliability of angle measurements with STAR.