BOptom (Hons) CertOcTher
Menai Eye Care, NSW
Zeiss Cirrus 5000 OCT
Zeiss Visucam retinal camera
Zeiss Humphrey Field Analyzer
Zeiss Forum: Glaucoma Workplace
Menai Eye Care is an independent full-scope practice focused on high-quality ocular health assessment and management, contact lens fittings and providing precise optical solutions for every individual patient.
We mainly prescribe Zeiss spectacle lenses due to their exceptional quality and functionality, so it made sense to source our equipment from Zeiss as well. Our team of optometrists appreciates the in-depth information the Zeiss products provide, allowing us to quantify eye structures in three dimensions with robust progression analysis over time. Our patients are very happy with our extended clinical services and as a result our team has increased job satisfaction.
The following case illustrates how the equipment is integrated into our examinations.
Pseudoexfoliation syndrome progressing to pseudoexfoliative glaucoma
A long-term patient presented for annual review, to have her driving licence form completed. A binocular Esterman field analysis on our Humphrey Field Analyzer (HFA) was undertaken, which she passed. She had nuclear sclerotic cataract affecting both eyes but reasonable vision at 6/7.5. Fundoscopy revealed a disc haemorrhage in the right eye. Tonometry showed symmetrical intraocular pressure (IOP) of 17 mmHg in both eyes. As disc haemorrhage is a risk factor for developing glaucoma, this patient was reviewed regularly until the haemorrhage resolved. Each subsequent appointment involved IOP measurement, fundoscopy and further glaucoma assessments. These included:
• retinal photographs with the Zeiss Visucam (stereoscopic photos), the gold standard for disc assessment, can be taken with this machine
• disc cube OCT scans with the Zeiss Cirrus 5000
• macula cube OCT scans with the Zeiss Cirrus 5000
• 24-2 threshold visual field analysis with the Humphrey Visual Field Analyzer
Pseudoexfoliative material was found on the anterior capsule of the right crystalline lens and in the anterior chamber angle on gonioscopy. These investigations were done four-monthly as per the NHMRC Glaucoma Guidelines.
Regular review over the next 18 months revealed fluctuating IOP in the right eye, from 17 mmHg up to 25 mmHg, characteristic of pseudoexfoliation syndrome. The IOP of the left eye has remained around 17 mmHg.
Figure 1A. RE: Photo reveals thinning of the superior and inferior neuro-retinal rim (Visucam)
Figure 1B. LE: Photo reveals thinning of the superior and inferior neuro-retinal rim (Visucam)
Disc photos with the Visucam (Figures 1A and 1B) documented that there was thinning of the superior and inferior neuro-retinal rim. An OCT scan was taken at each consultation. The disc cube scan (Figure 2) gives information about disc area and neuroretinal rim thickness as well as retinal nerve fibre layer (RNFL) thickness compared to patients of the same age and gender. It also quantifies disc size and symmetry of the RNFL and neural rim thickness.
Figure 2. Disc cube scan (Cirrus 5000)
In this case, the report identified borderline thinning of the neuro-retinal rim as well as the supero-temporal and inferior retinal nerve fibre layer, more progressed in the right eye.
The Cirrus 5000 progression analysis software uses two baselines for each subsequent comparison, which reduces the effect of measurement discrepancies. Once three scans have been taken, the glaucoma progression analysis (GPA) software can be utilised. The analysis is done on both the RNFL and the neuro-retinal rim and is very easy to interpret; it’s colour-coded to indicate likely or probable progression.
In this case, the GPA indicated likely progressive thinning of the superior and inferior (superior more substantially) RNFL in the right eye (Figure 3). The cup-to-disc ratio remained almost unchanged.
Figure 3. Guided Progression Analysis indicates likely progressive thinning of the superior and inferior retinal nerve fibre layer in the right eye (Cirrus 5000)
A macula cube scan is always performed as the Cirrus 5000 also measures the ganglion cell layer, which can be looked at in conjunction with the RNFL data in early glaucoma (Figure 4).
Figure 4. Macula cube scan (Cirrus 5000)
This patient’s OCT scans, digital photographs and visual field results are all exported to Zeiss Forum, a sophisticated imaging program which manages the data from these scans as well as creating reports and analyses. Each consulting room in my practice has Forum running on the computer, so the optometrist can view and discuss the scans and reports with the patient, freeing the OCT for use on other patients.
Zeiss Glaucoma Workplace collates the data from the visual field analyses and creates a progression analysis report over time. It also provides an invaluable feature aptly named a Structure-Function Report (Figure 5), which records the data from the disc cube scan (quantifying the structure of the nerve) with the overlying visual field results (indicating the function of the nerve). This report is simple to interpret; it’s colour-coded and enables us to see whether the two sets of data correlate as expected, making it easier to differentiate glaucomatous neuropathy from other pathology.
Figure 5. Structure-function report (Glaucoma Workplace)
Based on the right optic disc appearance, progressive RNFL thinning, visual field changes and raised IOP, our patient was referred to a local ophthalmologist and was comanaged by our practice and the ophthalmologist for 12 months before treatment was commenced. Arrangements were made for cataract extraction surgery to both eyes, as the cataracts had progressed and the patient’s best corrected vision was reduced to 6/12-. Cataract extraction would also aid in treating the pseudoexfoliation syndrome, reducing the IOP in the right eye. Topical anti-hypertensive medications were prescribed for the right eye in the interim.
Glaucoma Workplace has a new feature which means that these treatments can be included in the visual field progression report on Forum. The date of the cataract surgery and date of the topical anti-hypertensive drops can be added on the graph, as they will impact the data in the future.
The case illustrates the benefits of having complementary equipment in a primary health-care setting. The patient was able to have her eye examinations and glaucoma investigations performed locally, and she was referred in a timely manner for treatment.
This equipment from Zeiss works together to support accurate and complete assessment and management. The reports and analyses are easy to read and interpret, even when different practitioners are involved in the patient’s care. This is essential for a condition like glaucoma, in which a diagnosis is reached following a significant period of review and treatment is needed in a timely manner to avoid irreversible vision loss.