link   contact

Ocular Coherence Tomography (OCT) in ARMD
(Age Related Macular Degeneration)

Please click here for general information about Macular Degeneration

Matheson Optometrists now has invested the Zeiss Cirrus HD-OCT, Optical Coherence Tomography (OCT) available in Petersfield and Alresford practices. Andrew Matheson believes in using the best, most up-to-date technology to help detect eye conditions as early as possible. To make this happen we try and keep our charges for using this technology as low as reasonably possible. This is reflected in our private charge for providing an OCT scan of only £48.00. (See our fees)

Cirrus OCT image

The Zeiss Cirrus OCT

This is the newest, high-definition macula scanner on the market(see below).The Zeiss Cirrus HD-OCT, is a non-invasive technology used for imaging the retina - the multi-layered sensory tissue lining the back of the eye. The Optical Coherence Tomography (OCT) scanner was the first instrument to allow doctors to see cross-sectional images of the retina. This technology has been used in vitreo-retina care for some years. However, the latest much higher-definition scanning technology has revolutionized the way we image and diagnose macula conditions.

The Optical Coherence Tomography (OCT) scanner also is used to visualise the anterior chamber angle structures that can be affected in Narrow Angle Glaucoma, Plateau Iris Glaucoma and Pigment Dispersion Glaucoma, among other conditions.

The Optical Coherence Tomography (OCT) scanner is further used in assessing the thickness of the Retinal Nerve Fibre Layer adjacent to the Optic Disc (Optic Nerve Head). In Glaucoma and some other conditions, the nerve fibres leaving the eye via the optic nerve head die off and thus assessing the thickness of this nerve fibre layer can often show the early signs of glaucoma before the damage can be demonstrated by more convential metrhods such as Visual feild Testing.

Also used in Glaucoma assessment we utilise the Optical Coherence Tomography (OCT) scanner to measure the Centre Corneal Thickness, which gives us a measure of corneal rigidity or stiffness. Central corneal thickness can affect the readings optometrists and ophthalmologists obtain by tonometry (intra-ocular pressure (IOP) measurement), because a thicker and stiffer cornea will give an artificially elevated intra-ocular pressure (IOP) reading. Conversely, a thinner and less rigid cornea will produce a reading that is actually lower than the true pressure. Glaucoma may thus go undetected in people with thin a cornea or might be mis-diagnosed in people with a thicker cornea. In addition, having a thin cornea is an independant risk factor for Glaucoma as it may mean that the Optic Nerve Head is more vunerable to Glaucoma damage. 

With its advanced, next generation, precise algorithms, The Zeiss Cirrus provides Matheson Optometrists with highly detailed, high-definition maps and images of the macula and retinal structures. This allows us to make the most accurate diagnosis possible.

One of the most important benefits of this form of retinal scanning is that being able to scan the various layers of the retina not normally visible when an optometrist or ophthalmologist can let us detect the early signs of conditions such as Wet Macula Degeneration, Epiretinal Membrane and Macular Holes, often before it is visible by conventional methods. Because the more common Dry Macular Degeneration can change to the more agressive and nowadays, often treatable Wet Macular Degeneration, screening patients with dry macular degeneration with Optical Coherence Tomagraphy (OCT) can often pick up this change in type early enough for treatment to be started effectively

OCT showing a normal Macula Scan 

OCT showing an Epi-Retinal Membrane/Macular Pucker

Matheson Optometrists now has invested the Zeiss Cirrus HD-OCT, Optical Coherence Tomography (OCT) available in Petersfield and Alresford practices. It Utilises Spectral Doimain(also known as Fourier Domain or transform OCT), Optical Coherence Tomography (OCT) rather than the earlier more common Time Domain technology. Spectral Domain is 60-70 times faster and so is less affected by such thiungs as eye movement artifacts. It uses a broader band light source with improved depth resolution and aquisition speed. 

 

The Amsler grid

An Amsler grid is a useful tool for monitoring your central visual field. It is an important way to detect early and sometimes subtle visual changes in a variety of macular diseases such as ARMD (age-related macular degeneration) and diabetic macular oedema. It is also helpful in monitoring changes in vision once they have been detected. With the Amsler grid, each eye is tested separately by you. This helps you to recognize visual symptoms which are in one eye only

 

Please click this link for more information and a larger, printable version of this grid

Amsler Grid