Ian Breadon, Clifton Hill VIC
Product: Cirrus HD-OCT 400
Supplier: Carl Zeiss Australia
Our inner-suburban optometry practice was established in 1985 in an upstairs room and migrated downstairs to a shop front in 1996. We are part of a B-grade shopping strip, with a predominantly local patient base, perhaps seeing fewer pensioners than is usual because of our proximity to the Australian College of Optometry, which provides low-cost eye care to Melbourne’s pensioner community.
Our practice emphasises personal care. Most appointments last about 45 minutes, allowing us enough time to dilate on indication, take retinal photographs and talk to the patient.
Introducing an OCT to a practice of just over one equivalent full-time optometrist means we will struggle to make the instrument pay for itself, but this was not a prerequisite for purchase. We felt that an OCT, much like retinal photography 10 years ago, was a major step in our ability to detect and diagnose retinal conditions with more certainty, and it would help us make better decisions about when to refer for specialist care.
Cirrus HD-OCT 400
The choice of machine was difficult because OCT scans are unfamiliar images to optometrists. We were unfamiliar with assessing retinal architecture in cross section, and although the diagrammatic results are impressive and largely self-explanatory, at first the numerical analysis was confusing.
This means that while the operation of the machine is relatively straightforward, the interpretation of results takes some time to master. We made the decision not to charge for scans for most of the first six months of operation.
We found the Cirrus 400 appealing because of its compact footprint, its logical displays and its price (a Southern Regional Congress special). Size was important because, like the retinal camera, it is installed in the primary consulting room and is operated by the optometrist who also presents the results. This is not done by an assistant.
We had heard that after-sales support from Carl Zeiss was reliable and timely, although most other local suppliers also appear to perform well on this measure.
So far, we have required two service calls—the first to correct a calibration error and the second because of an interaction with the Windows operating system which hung the machine temporarily. In both cases, we were operating again within four hours.
We financed the $80,000 purchase by lease, with monthly payments of $1,844 over a five-year term with no significant residual. Initially, we had set patient fees of $90 for macular/ONH scans, but have reduced this to $75. This means that to recover machine costs alone, we would need to perform one to two scans per day.
There are other costs associated with an OCT. For example, it may be necessary to bring a patient back for a scan if there is insufficient time available. No Medicare fee is available for the second visit and no revenue is generated from appliance sales, so it displaces a fee-paying consultation or part consultation.
Regardless, the introduction of the OCT is comparable to the introduction of previously new technologies such as computerised perimetry 30 years ago and retinal photography 10 years ago. These technologies may not be applied to every patient, but they enable a practice to provide a higher level of patient care for the entire patient base.
Patients almost always show a genuine interest in the OCT when its function is demonstrated. Recent public education campaigns about glaucoma and macular degeneration have heightened patient awareness and interest in these conditions. It must be noticeable to all clinicians that patients are much more actively interested in their ocular health.
Like retinal photography, OCT is an excellent education aid that makes patients partners in their eye health care.
Ganglion cell analysis reveals cell loss
A 66-year-old female patient with significant optic nerve head cupping, which had been stable over several years, presented for a routine eye examination.
The patient had normal blood pressure and took no medications, and there was no family history of eye disease. Intra-ocular pressures were 15/14 mmHg.
Visual fields were normal two years ago, and were measured again after the recent visit, with no significant defect.
OCT scans revealed left temporal thinning of the retinal nerve fibre layer (ONH and RFNL OU Analysis). A ganglion cell analysis of the macular cube showed significant cell loss in all segments in the left eye, particularly superiorly. On this basis the patient was referred.
The ophthalmologist measured IOP as 16/16 mmHg, and noted left inferior and superior disc neural rim thinning, also possible right inferior rim thinning.
After a further field test showed an early arcuate left inferonasal arcuate scotoma, (IOP 13/13 mmHg at this visit) treatment with Xalatan drops was commenced.
An OCT device is also useful in detecting macular lesions, especially subtle macular oedema. We have been able to monitor a patient with recurrent macular oedema secondary to a branch retinal vein occlusion, and when macular scans show significant fluid in the area, the patient is referred for prompt treatment.
Fig. 1 RNFL Analysis
Fig. 2 Ganglion Analysis
- Ian Breadon