A prospective study on effectiveness of elevated intraocular pressure as a criterion for glaucoma referrals by optometric practitioners in Sweden

Comparison of disease severity in glaucoma patients identified by screening in the 1990s and in routine clinical care in the 2010s in Sweden

BACKGROUND AND PURPOSE

In a previous study comparing the amount of visual field damage at presentation in patients having open-angle glaucoma (OAG) identified through screening and in patients diagnosed in routine clinical practice in the 1990s, the damage was considerably worse in the clinically diagnosed patients. In the present study we compare visual field damage at presentation in the same 402 screened patients with that seen in 281 newly detected previously untreated patients clinically diagnosed in the 2010s.

METHODS

The perimetric visual field index mean deviation (MD) was compared in the two groups of patients.

RESULTS

In the clinical patients diagnosed with bilateral visual field damage the median MD was -5.1 dB in the better eye and -13.0 dB in the worse eye. In the screened patients the median MD in the better eye was -6.5 dB and -11.5 dB in the worse eye. The differences between the clinical and screened patients were non-significant, p = 0.28 and p = 0.67 respectively. More clinical patients had severe visual field loss, defined as MD less than -20 dB, in the worse eye than in the screened patients, 18.5% versus 12.7% respectively, p = 0.037.

CONCLUSION

The visual field damage at presentation in clinically diagnosed OAG patients has improved in the past 20 years, but the proportion of patients with severe visual field loss in at least one eye, almost 20%, is still unacceptably high considering that severe visual field damage at presentation is the most important risk factor for later development of glaucoma blindness.

Outcomes of newly referred patients with suspected angle closure: do we need to redefine the clinical pathways?

BACKGROUND/OBJECTIVES

To investigate outcomes of referrals for suspected angle closure and explore whether anterior segment optical coherence tomography (AS-OCT) can be used to tighten triaging criteria in a glaucoma virtual clinic.

SUBJECTS/METHODS

Retrospectively collected data. The first audit (04/2018-03/2019) identified referrals for suspected angle closure without other glaucoma-related findings (primary angle closure suspect (PACS) referrals). All patients underwent gonioscopy. The second audit (04-08/2019) identified patients with suspected angle closure in a virtual clinic. Management outcomes were assessed, using gonioscopy as reference standard. The outcomes of the second audit were re-audited after changing the triaging criterion from angle width <10° to iridotrabecular contact (ITC) in ≥1 quadrants on AS-OCT.

RESULTS

Out of 1754 glaucoma referrals (first audit), 24.6% (431/1754) were PACS referrals. Of these, only 10.7% (42/393) had an occludable angle on gonioscopy, with 97.6% (41/42) being PACS. Of these, 78% (32/41) underwent laser peripheral iridotomy. Out of 137 referrals in the virtual clinic (second audit), 66.4% (91/137) were triaged to the face-to-face clinic. Of these, 31.9% (29/91) were discharged. AS-OCT had positive and negative predictive value of 74.3% (95% confidence intervals (CI) 57.8-86.0) and 82.1% (95% CI 70.0-90.2%), respectively, in detecting ITC in ≥1 quadrants. In the re-audit 45.9% (45/98) of those with suspected angle closure were triaged for gonioscopy, with 24.4% (11/45) of them being discharged.

CONCLUSION

PACS referrals represent a substantial burden to hospital-based services and their accuracy is low. ITC in ≥1 quadrants on AS-OCT can be useful in triaging those who need further evaluation with gonioscopy.

Effectiveness of Elevated Intraocular Pressure as a Criterion for Glaucoma Referral After 6 Years of Follow-Up

Purpose

To evaluate the long-term predictive value of the need to treat patients referred by optometric practitioners, regarding glaucoma, in Malmö, Sweden, using intraocular pressure (IOP) as the primary referral criterion.

Patients and Methods

This retrospective study included 94 of 108 (87%) individuals referred to the Skåne University Hospital in Malmö, Sweden, for elevated IOP during 2012–2013. Data were extracted from patient records by the end of 2019. Positive outcome was defined as glaucoma, treated suspected glaucoma or treated ocular hypertension (OH) at referral or during the follow-up period. Positive predictive values (PPV) were calculated using different hypothetical thresholds for age and IOP-levels. Long-term follow-up was used to evaluate whether the first visit diagnoses would change over time, and if this would affect the effectiveness of the referrals.

Results

Elevated IOP was the only referral criterion in 84% (n=79). In 28 patients (35%) among the IOP-only referrals, no ocular disease was found, and 26 patients (33%) had a positive outcome at the first visit. Median follow-up time was 6.4 years. PPV according to diagnosis after follow-up was 42% (95% CI: 32–54%) for IOP-only referrals. Including thresholds of ≥45 years of age in combination with an IOP of ≥25 mmHg in the referral criteria would have reduced the number of IOP-only referrals by 27% (21 of 79), and increased the PPV to 57% (95% CI: 45–71%) at the last visit. No positive outcome would have been missed, among those that were followed-up after the first visit, when applying these thresholds for referral, over a follow-up period of six years.

Conclusion

Using only elevated IOP as referral criterion showed a poor accuracy for predicting those that require IOP lowering treatment. The long-term follow-up allowed us to verify the applicability of higher hypothetical threshold requirements on age and IOP for glaucoma referrals from optometric practices.