Clinical imaging: OCT clinical indicators for functional testing – Case #8

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With a focus on diagnosis of eye disease, particularly glaucoma, the following clinical images demonstrate the importance of performing appropriate functional testing when it is clinically indicated in structural assessment.

Case #8

Case supplied by Simon Kelly, Specsavers Runaway Bay, QLD

Px: 79-year-old female
IOPs: 12mmHg both RE and LE

OCT widefield reports:

Consider the structural information provided in the OCT scans above:

  • What’s normal?
  • What’s abnormal?
  • Are there any clinical indications for functional testing?

This patient presented a year earlier with the following OCT scan in the RE. Note the change in average RNFL thickness (90 microns compared to 76 microns). OCT trend maps were also analysed with similar information being presented.

Discussion

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The OCT widefield reports contain the following clinical indicators for functional testing:

  • RNFL thickness outside normative limits over both visits for the RE
  • A reduction of average RNFL thickness over a year that is outside normal age-related thinning rates
  • Significant beta peripapillary atrophy visible on fundus photography as well as stereoscopic examination of the retina.

Visual field results:

The visual field results are of low test reliability, with pattern standard deviation appearing suspicious. However, repeat visual fields are required for this patient.

Repeat visual fields were of similar appearance. Using the RANZCO referral guidelines, this patient falls under a category C glaucoma suspect. However, the change in RNFL thickness could warrant a differential of pre-perimetric normal-tension glaucoma.

The patient was resistant to a referral and agreed to a 6-monthly review schedule with the optometrist. Initiation of treatment with a referral to an ophthalmologist within 4 months could be considered. However, in this case, the decision to monitor the patient rather than initiate treatment was made after taking into account discussions with the patient, as well as the relatively clear baseline visual fields and correlation to age and risk of progression to significant visual impact.

The case was later discussed during an Ophthalmologist Local Education and Engagement Program session. Given the structural and functional assessment results, the ophthalmologist agreed with the optometrist’s management plan of closely monitoring the patient as a normal-tension glaucoma suspect.

More in the ‘OCT clinical indicators for functional testing’ series
Case #1 and series introduction
Case #2
Case #3
Case #4
Case #5
Case #6
Case #7
Case #8

Specsavers optometrists can now access additional OCT training based on this series on iLearn using the following path: Available Courses > Optometrist > Optical coherence tomography (OCT) > 04: OCT Case Studies
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