Sensitivity of Swedish interactive threshold algorithm compared with standard full threshold algorithm in Humphrey visual field testing

doi:10.1016/S0161-6420(00)00140-8

Ophthalmology

Volume 107, Issue 7, July 2000, Pages 1303-1308

Presented in part at the American Academy of Ophthalmology annual meeting, New Orleans, Louisiana, November 1998.

https://doi.org/10.1016/S0161-6420(00)00140-8 Get rights and content

Abstract

Objective

To compare the sensitivity of Swedish interactive threshold algorithm (SITA) strategies with the standard full threshold algorithm in the Humphrey Field Analyzer.

Design

Observational case series.

Participants

Forty-eight glaucoma patients who were experienced in automated perimetry.

Testing

Central field testing was performed with the 30-2 program using standard full threshold (SFT), SITA standard (SS), and SITA fast (SF) strategies. All three tests were carried out on each of four different days in a span of 4 weeks.

Main outcome measures

Sensitivity, repeatability, time saved, and the extent of defect in the SITA strategies were compared with those of the SFT.

Results

The sensitivity of SS and SF were 95.12% and 92.68%, respectively. The time saved in SS and SF was 53.12 ± 9.51% and 70.69 ± 8.81%, respectively. The repeatability as assessed by intraclass correlation showed excellent repeatability for the SFT and SS strategies and excellent to poor repeatability with the SF strategy. With increasing mean deviation, the defects (significant at P < 0.5%) in the pattern deviation plots tended to be more in the SITA strategies as compared with SFT.

Conclusions

Swedish interactive threshold algorithm strategies have good sensitivity and are significantly faster as compared with the standard threshold algorithm. The repeatability of the SFT and SS strategies are excellent, whereas that of the SF strategy is variable.

Section snippets

Patients and methods

A total of 48 glaucoma patients who were experienced in automated perimetry were enrolled into the study. One eye of each patient was included in the study. Each patient underwent visual field evaluations on four different days within a span of 4 weeks. On each visit, the 30-2 program with standard full thresholding (SFT) using Humphrey Field Analyzer I (HFA; Model 640, Humphrey Systems, Dublin, CA), and SITA standard (SS) and SITA fast (SF) with HFA II (Model 750) were performed. The sequence

Results

The sensitivity of SFT, SS, and SF as compared with the gold standard derived from the three visits of the SFT is shown in Table 1, Table 2, Table 3. The sensitivity of SFT and SS is 95.12%, and that of SF is 92.68%.

The repeatability of the tests as assessed by the intraclass correlation is shown in Table 4. The correlation between the visits was excellent for the number of points deviating at P < 1% in all the strategies in the MD, and in the PSD for the SFT and the SS strategies. The PSD in

Discussion

Computerized threshold perimetry is currently the best way of estimating the hill of vision. The time consumed in plotting the central 30° field with the present 4–2 algorithm in the Humphrey perimeter could be 15 to 20 minutes, depending on the severity of the field defect. Alternative strategies for visual field testing that took less time, such as the FASTPAC, resulted in saving time, but the results were found to be less reliable.6, 7 The SITA family of thresholding algorithms have been

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To determine the effect of transitioning from Swedish Interactive Thresholding Algorithm (SITA) Standard to SITA Faster on visual field (VF) performance in glaucomatous eyes with a broad spectrum of disease severity undergoing longitudinal VF testing in a real-world clinical setting.
Retrospective, longitudinal study.
A total of 421 patients (766 eyes) with manifest or suspect glaucoma followed at a single institution.
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The difference in ΔMD between Standard-Standard and Standard-Faster sequence by mild, moderate, and advanced disease severity.
In eyes with mild or suspect glaucoma, there was no significant difference in ΔMD between Standard-Faster and Standard-Standard sequences (−0.23 decibels [dB]; 95% confidence interval [CI], −0.60 to 0.15 dB). However, the Standard-Faster sequence was associated with a 0.87 dB (95% CI, 0.18–1.57 dB) improvement in ΔMD compared with the Standard-Standard sequence in eyes with moderate glaucoma and a 1.49 dB (95% CI, 0.79–2.19 dB) improvement in ΔMD in eyes with advanced glaucoma.
Converting to SITA Faster in eyes that were previously followed with SITA Standard led to similar VF performance in mild glaucoma but resulted in higher MD values in moderate and advanced glaucoma. For patients with moderate or severe glaucoma, this may conceal disease progression when transitioning testing strategies.
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For the 16 604 eyes with 2 initial ONL results, the prevalence of a subsequent WNL result increased from 0.1% for MD < −12 dB to 13.8% for MD ≥−3 dB. Compared with models with VF global indices, the AUC of predictive models increased from 0.669 (MD ≥−3 dB) and 0.697 (−6 dB ≤ MD < −3 dB) to 0.770 and 0.820, respectively, by adding VF mismatch features and computationally derived VF archetypes (P < 0.001 for both). The GHT results reversal was associated with a large mismatch between baseline VFs. Moreover, the GHT results reversal was associated more with VF archetypes of nonglaucomatous loss, severe widespread loss, and lens rim artifacts. For a subset of 97 eyes, using our model to predict absence of glaucoma based on clinical evidence after 2 ONL results yielded significantly better prediction accuracy (87.7%; P < 0.001) than predicting GHT results reversal (68.8%) with a prescribed specificity 67.7%.
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Citation Excerpt :
One limitation of this study may be that, several years into the study, a change from the full-threshold strategy to SITA standard in SAP was made to save test time. We think this change did not alter the results significantly because both tests have been shown to yield similar outcomes.18,19 Importantly, the full-threshold strategy was repeated to confirm any abnormal SITA standard fields.
Short-wavelength automated perimetry (SWAP) has been claimed to predict conversion to glaucoma 3 to 4 years before standard automated perimetry (SAP) defects occur. This study compared the moment of glaucomatous conversion between SWAP and SAP.
Prospective, longitudinal follow-up study.
Four hundred sixteen subjects with ocular hypertension (intraocular pressure ≥22 and ≤32 mmHg and normal visual fields).
A Humphrey Field Analyzer (24-2 program; Carl Zeiss Meditec, Dublin, CA) was used to perform both SWAP and SAP. All participants were tested once every half year during 7 to 10 years or until the onset of conversion (study end point). The conversion to glaucoma was defined as a reproducible glaucomatous visual field defect in SAP.
The moment of onset of a reproducible defect in SAP was compared with that in SWAP.
Of the 416 initial participants, 24 eyes of 21 subjects showed conversion in SAP. Of these eyes, 22 did not show earlier conversion in SWAP than in SAP. Standard automated perimetry even showed earlier conversion than SWAP in 15 cases. In only 2 eyes did SWAP show earlier conversion by up to 18 months.
These results do not support the notion that SWAP generally predicts conversion to glaucoma in SAP. Instead, SAP appears to be at least as sensitive to conversion as SWAP in a large majority of eyes.
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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^☆: The authors have no proprietary interest in any instrument or equipment discussed in the manuscript.

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Sensitivity of Swedish interactive threshold algorithm compared with standard full threshold algorithm in Humphrey visual field testing☆

Abstract

Objective

Design

Participants

Testing

Main outcome measures

Results

Conclusions

Section snippets

Patients and methods

Results

Discussion

Am J Ophthalmol

Ophthalmology

Ophthalmology

Ophthalmology