A prospective study on effectiveness of elevated intraocular pressure as a criterion for glaucoma referrals by...

To evaluate the outcome of referrals for suspected glaucoma based on elevated intraocular pressure (IOP) made by optometric practitioners in Sweden.

This prospective study included 95 individuals referred to the Skåne University Hospital Malmö, Sweden, during 2019, by optometric practitioners, based on elevated IOP. Positive outcome was defined as a diagnosis of glaucoma, or a diagnosis of suspected glaucoma. Referral accuracy was analysed. Positive predictive values (PPV) of different hypothetical IOP and age thresholds were calculated.

In 34% (95% CI: 24-43%) of the referrals, no eye disease was found. Intraocular pressure (IOP) was the only referral criterion in 77% (73/95). The PPV was 35% (95% CI: 25-45%) for all referrals, 27% (95% CI: 16-38%) for IOP-only referrals and 59% (95% CI: 36-82%) for referrals including additional findings. In IOP-only referrals, no definite diagnosis of glaucoma was made in any patients <45 years of age. Applying a theoretical age limit of ≥45 years with a hypothetical IOP limit of ≥25 mmHg in patients 45-69 years and of ≥22 mmHg in patients ≥70 years increased the PPV to 42% (95% CI: 27-57%). IOP-only referrals would have been reduced by 27% without missing any glaucoma cases.

The overall predictive value of the referrals was poor. Glaucoma resources would have been used more effectively by increasing the required age for IOP-only referrals to ≥45 years in combination with different IOP thresholds for certain age groups.