Restricted Access

You must be logged in to view this content.

Art meets science

$currentPage/@nodeName

Mark Koszek
BOptom MOptom GradCertOcTher
Founding partner EyeQ Optometrists

Product
Nidek RS-330 RetinaScan DUO

Supplier
Designs For Vision

 

When I began practising in 1995, optometry was a very different profession. The first practice I worked in had a refractor head, keratometer, slitlamp and trial set. There was no BIO, no visual field analyser, no OCT, no Optos, no corneal topographer, no internet, no computer.

I was by myself in a new practice without a mentor; I didn’t even have a receptionist. If I saw something strange, I had to look up Kanski and hope there was a photo of the condition.

In those early days, diagnosis felt like it was more art than science, and if I had to describe my early optometric life as an art movement, it was definitely minimalism. Glaucoma was always a real challenge. I had to rely on disc appearance and pressures; I didn’t have a visual field analyser and my first OCT was still 18 years away.

Looking back, it was positively mediaeval but it did help me develop an acute eye for detail. After 22 years, I estimate that I’ve seen more than 150,000 discs. I’ve become an expert on C/D ratios, and I regularly challenge my expertise by comparing my vertical C/D ratios to the OCT’s vertical C/D ratios. It’s uncanny how close I can get.

 

CASE REPORT

Kay, a 70-year-old woman, entered for a test in 2011. Kay was healthy, with normal acuities and IOPs R 13

L 15 mmHg. Hardly anything to inspire fear but it was the appearance of her left disc that troubled me. The vertical C/D ratios were R 0.6 L 0.7. The left inferior neuro-retinal rim appeared attenuated. Her discs prompted me to do a visual fields test, which revealed a left superior arcuate scotoma. I subsequently referred Kay as a normal tension glaucoma suspect. The local ophthalmologist confirmed my diagnosis and prescribed Xalatan. She had significant side-effects, as she did too with Timoptol. Eventually, the ophthalmologist performed selective laser trabeculoplasty (SLT).

Kay returned recently for a review after not seeing the ophthalmologist for 18 months. IOPs were R 10 mmHg L 14 mmHg. Again, the left disc appeared more damaged than the right. I put my C/D ratios skills to the test and estimated the vertical ratios at R 0.75 L 0.85.

Glaucoma patients can often throw you red herrings; during visual fields tests, they often try so hard that they in fact become completely unreliable. Kay was no different; her fixation losses and false positives were high and her visual field indexes R 99 per cent L 93 per cent were masking a more serious defect.

Thankfully, it’s 2017 and we have an OCT. At our practice at Ramsgate Beach we have the Nidek RS-330 Retina Scan Duo from Designs For Vision.

The RS-330 allows me to quantify glaucoma damage and chart progression. Previously, we had to depend on the highly unreliable visual fields test and IOPs, which are nearly irrelevant when it comes to normal tension glaucoma. The Nidek provides an enormous amount of useful information: disc size, cup size, ganglion cell complex thickness maps, inter-eye symmetry and of course C/D ratios. The RS-330 estimated Kay’s vertical C/D ratio at R 0.76 L 0.85, which was uncannily close to my own estimate.

 

EQ-226-Figure -1 - Online

Figure 1. Optic nerve head and retinal nerve fibre layer analysis

 

The ganglion cell complex scan is an invaluable detector of early glaucomatous damage. Looking at Kay’s right TSNIT alone (Figure 1) would suggest that her discs and nerve fibre layer are healthy, yet look at her ganglion cell complex scan and she has advanced glaucomatous damage, especially in the right superior retina (Figure 2).

 

EQ-226-Figure -2 - Online

Figure 2. Ganglion cell complex scan

 

The glaucoma progression analysis suggested that Kay’s left ganglion cell complex thickness had decreased compared to her previous two tests. In days past, there would have been no way I could have detected such deterioration, considering her unreliable fields tests. The left superior nasal sector had decreased 10 microns in thickness since her original scan two years previously (Figure 3).

 

EQ-226-Figure -3 - Online

Figure 3. Glaucoma progressions analysis reveals thickness decrease

 

I subsequently referred Kay back to the ophthalmologist, who repeated SLT.

I reflect back on my career in astonishment. While I’m thankful for my ‘minimalistic’ beginnings, where I honed my eye for detail, I marvel at the technological changes which have greatly improved our ability to diagnose and manage eye disease.



Like us on Facebook




Subscribe to our News RSS Feed

Latest Tweets




Recent Comments