I first came across the AOS software at Optrafair earlier this year. The Italian software designer was keen to show me the potential for his creation, then yet to be commercially released, and I was duly impressed. I am pleased to say the AOS package is now available to UK clinicians from Keeler UK.
Grading
All of us working in eye health regularly assess the anterior eye. It is now standard practice to record our findings, not just by image capture where a slit-lamp camera system is available, but by use of one of the recognised grading systems.
Grading offers some key benefits to practice:1
- Accuracy and consistency in clinical record keeping leading to more meaningful communication of clinical cases to fellow health professionals
- Increased focus on clinical records in cases of complaints and potential legal action means standardised and comprehensive record keeping has added relevance to today’s eye care practitioner
- Effective monitoring of the health of an eye, whether related to the wearing a contact lens or to any ongoing ocular surface anomaly either under treatment or for diagnostic or management decision purposes
- An accurate means of detecting change that can occur during contact lens use and provide the practitioner with the necessary information to intervene to minimise the risk of a chronic adverse reaction to the contact lens.
Once baseline data for a range of clinical variables is recorded using grading, these may then be monitored throughout the course of the patients wearing experience so offering a useful reflection of ocular surface and adnexal integrity.
Most clinicians are now familiar with grading scales, whether that be the CCLRU (figure 1, now rebranded as the Brien Holden Vision Institute or BHVI system), or the Efron grading scales. The former is based around photographs of six conditions, two of which are presented in multiple manifestations while the latter consists of a series of artist illustrated depictions of 16 different conditions.
The BHI photographic scales have been criticised for the lack of perfect homogeneity between images representing the same condition, either in terms of different illumination conditions or variable size of the area under display.
While Efron overcomes these difficulties by encouraging artistic clarity and licence so as to emphasise and isolate the condition that is being evaluated, it is considered by some a departure from the real life situation in as much as different conditions feed and depend on each other and, therefore, occur simultaneously and should appear as such in a single image.1
Christie has noted that the BHVI photographic scales have been criticised for the lack of perfect homogeneity between images representing the same condition, either in terms of different illumination conditions or variable size of the area under display.
One obvious concern with grading is its subjective nature and inter-practitioner variation is commonplace. Many studies have shown that the experience of the practitioner is an influence upon grading accuracy, and others have therefore instead recommended an objective approach to be more useful.2-5 The AOS software is just such an objective solution (figure 2).
Figure 2: AOS heat maps of the ocular surface
AOS
The AOS software allows images of the anterior eye to be analysed in a variety of ways that can then be more easily interpreted and recorded and reflect even the most subtle changes between imaging.
In so doing it removes the subjective error that might otherwise risk misinterpretation and mismanagement of any individual presentation. There are a number of different modes which readers will immediately see as useful.
Figure 3: Temporal bulbar hyperaemia in a soft lens wearer. What should be recorded?
Bulbar redness
Figure 3 shows temporal bulbar hyperaemia on the eye of a soft contact lens wearer. The image is being displayed within AOS and the tab for bulbar redness has been hit. A specific area of the bulbar conjunctiva can then be defined (figure 4) and the vessels are then displayed as black lines.
Figure 4: Vessel outline and grading
This allows the software to then calculate the percentage of vascular tissue, in this case 24%, and also to show a grade that may be displayed (1.5). As it is a photographic analysis, the best analogy is with the well-respected BHVI grading score. I is also possible to display the same area as a ‘redness map’, as in figure 5.
Figure 5: Redness map of the same area as in figure 4
This shows much more clearly hot areas of hyperaemic prominence against cooler less vascularised areas. The results are then saved but can also be printed out as a report, pre-specified with your own practice details (figure 6).
Figure 6: Report designated as from your own practice
Lid redness
The Lid Redness tool detects palpebral conjunctival redness, again using the zero to four scale. It presents results in the industry standard five-sector grid (figure 7). This allows automatic sectoral grading of hyperaemia on the everted palpebral conjunctival surface (figure 8).
Corneal staining
Perhaps vulnerable to the greatest levels of subjective variation, even with the hopefully now ubiquitous use of an orange absorption filter concurrent with the blue excitation filter, accurate evaluation of fluorescein staining is a key component of any anterior eye assessment.
Figure 8: Sectoral grading of hyperaemia on the everted palpebral conjunctival surface
Figure 9 shows a fluorescein image displayed within AOS. Any area of interest may then be outlined and individual points of stain or fluorescence are then displayed clearly as red (figure 9).
Figure 9: Fluorescein image displayed within AOS
Selection of the grid function allows the corneal surface to be split into distinct zones (figure 10) and the levels of staining within each zone to be quantified easily and accurately (figure 11.).
Figure 10: Corneal surface to be split into distinct zones
As before, you can then generate a staining report with your practitioner insignia prominently displayed (figure 12).
Figure 11: Levels of staining within each zone
Figure 12: Staining report
Road test
I have acquired the AOS software and am currently putting it through its paces. As shown here, my initial view is that it is very easy to use and offers accurate and repeatable quantitative values for a range of important anterior presentations essential for clinical management of our patients.
I will be publishing a further gallery of images from the system in a forthcoming issue once I have finished my trial. The software is available as a one-off purchase from Keeler UK or as a licensed program via monthly payments. Updates and developments are included in the price and I guess functionality is likely to increase in the coming years. I would not be surprised if something similar for retinal imaging was to appear soon too but, as yet, this has not been confirmed.
Further information from www.keeler.co.uk
References
1 Christie C. Anterior segment clinical grading in CLs practice. Optician, 03.07.2015.
2 Bailey et al (1991), Clinical Grading and the Effects of Scaling, Investigative Ophthalmology & Visual Science, Vol 32, No2, Pages 422-432
3 Wolffsohn et al (2009), Simplified recording of soft contact lens fit, Contact Lens & Anterior Eye 32, Pages 37-42
4 Cardona & Serés (2009), Grading Contact Lens Complications: The Effect of Knowledge on Grading Accuracy, Current Eye Research, No 34(12), Pages 1074-1081
5 Belda-Salmerón et al (2015), Objective analysis of contact lens fit, Contact Lens & Anterior Eye 38, Pages 163-167