17, 18, 19, 20 In particular, for the HVF (total deviation plot), a hemifield was defined as abnormal if a cluster had two or more contiguous points at p<0.01, or three or more contiguous points at p<0.05 with at least one point at p<0.01. For the HVF and mfVEP tests, cluster criteria were used as previously defined. Procedures adhered to the tenets of the Declaration of Helsinki and the protocol was approved by the committee of the Institutional Board of Research Associates of Columbia University.Įach hemifield was classified as normal or abnormal based upon the following criteria. Informed consent was obtained from all subjects before their participation. The 25 individuals serving as controls had a mean age of 58.8 (SD 8.2) years and normal fundus examinations and normal 24‐2 HVF tests. When the patient's eyes were categorised as less or more affected based upon the MD, the average MDs were −3.85 (3.79) dB (less affected eyes) and −9.91 (5.73) dB (more affected eyes). Overall the average MD was −6.88 (5.71) dB. To be considered abnormal, the HVF had to have a glaucoma hemifield test (GHT) outside normal limits and/or a pattern standard deviation (PSD) or mean deviation (MD) with p<0.05.

All patients had at least one eye with a diagnosis of glaucoma (n = 38 patients) and/or optic nerve drusen (n = 2) and an abnormal 24‐2 Humphrey visual field (HVF). With the exception of two patients, all tests were performed within a 12‐month period (median 86 days). A preliminary report was presented at the 2006 meeting of the Association for Research in Vision and Ophthalmology.įorty patients, with a mean age of 61.4 (SD 12.2) years, were selected from a larger set of patients enrolled in a prospective clinical study to include those tested with OCT, mfVEP and SAP. The hemifields missed by the OCT were evaluated to see if the cause could be inferred. Thus, the accuracy of the OCT RNFL test was assessed for hemifields abnormal on two functional tests. In particular, for a hemifield to be classified as abnormal, it had to show an abnormal cluster of points on both the SAP and mfVEP tests. Here we use a similar approach to examine the OCT results for hemifields in which it was fairly certain that there was glaucomatous damage. Using this logic, they showed that the pattern electroretinogram was normal in over 25% of the eyes defined as abnormal on both SAP and mfVEP tests. The logic being that if these two very different functional tests were abnormal, then it is extremely likely that glaucomatous damage was present.

To minimise this problem, Hood et al 16 defined a glaucomatous eye as one in which both SAP and multifocal visual evoked potential (mfVEP) tests were abnormal. That is, there is no test for which a positive result necessarily means glaucomatous damage is present. In the case of glaucoma, this is easier said than done as we lack a “gold standard” for defining glaucomatous damage. To better understand the limits of a technique for detecting glaucomatous damage, it is useful to examine the conditions under which the technique misses glaucomatous damage. With the OCT, RNFL thickness is most often measured using peripapillary scanning around the optic disc.Ī number of studies have reported that optical coherence tomography (OCT) can detect glaucomatous damage with moderate to reasonably high sensitivity and specificity. 1 Optical coherence tomography (OCT) is an imaging technology developed to detect damage to the retina and retinal nerve fibre layer (RNFL). For example, it is said that significant retinal ganglion cell damage can take place before SAP reveals a deficit. Although standard automated perimetry (SAP) is an accepted clinical procedure for detecting glaucomatous damage, it is not without its problems.

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