A cohort study of participants with ocular hypertension who participated in the Ocular Hypertension Treatment Study (OHTS) shows that the 20-year cumulative incidence of primary open-angle glaucoma (POAG) was 46% in 1 or both eyes, and the cumulative incidence of visual field loss was 25%, according to researchers. This information may help clinicians — and patients — make more informed decisions about the management of ocular hypertension.

Ocular hypertension is a key risk factor for developing POAG. OHTS was designed to address the debate regarding how best to manage patients with it.

To determine the cumulative incidence and severity of POAG, participants in the OHTS were followed up from February 1994 to December 2008 in 22 clinics. Data were collected after 20 years of follow up (from January 2016 to April 2019) or within 2 years of death. Analyses were performed from July 2019 to December 2020.


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From February 28, 1994, to June 2, 2002 (phase 1), participants were randomized to receive either topical ocular hypotensive medication (medication group) or close observation (observation group). From June 3, 2002, to December 30, 2008 (phase 2), both randomization groups received medication. Beginning in 2009, treatment was no longer determined by study protocol. From January 7, 2016, to April 15, 2019 (phase 3), participants received ophthalmic examinations and visual function assessments.

A total of 1636 individuals 55.4±9.6 years; 931 women [56.9%]; 1138 White participants [69.6%]; 407 Black participants [24.9%]) were randomized in phase 1 of the clinical trial. Of those, 483 participants (29.5%) developed POAG in 1 or both eyes (unadjusted incidence).

After adjusting for exposure time, the 20-year cumulative incidence of POAG in 1 or both eyes was:

  • 45.6% (95%CI, 42.3% to 48.8%) among all participants.
  • 49.3% (95%CI, 44.5% to 53.8%) among participants in the observation group.
  • 41.9% (95%CI, 37.2% to 46.3%) among participants in the medication group.
  • 55.2% (95%CI, 47.9% to 61.5%) among Black participants.
  • 42.7% (95%CI, 38.9% to 46.3%) among participants of other races.

The 20-year cumulative incidence for visual field loss was 25.2% (95%CI, 22.5% to 27.8%). Using a 5-factor baseline model, the cumulative incidence of POAG among participants in the low-, medium-, and high-risk tertiles was 31.7% (95%CI, 26.4% to 36.6%), 47.6% (95%CI, 41.6% to 53.0%), and 59.8% (95%CI, 53.1% to 65.5%), respectively.

However, investigators advise caution in generalizing the incidence of POAG reported in the OHTS cohort to patients seen in standard clinical settings.

Researchers note several limitations of their study, including a limited baseline intraocular pressure range of 21 to 32mmHg, collection of medical history and family history of glaucoma only by self-report, loss to follow-up over the 20-year study period, missing data on participants, non-randomized treatment after phase 2, and lack of optical coherence tomography measurements until phase 3.

The study’s authors did note a few limitations, including its small sample size and selection bias. However, they contend that their findings are consistent with previous studies investigating the relationship between dry eye and aromatase inhibitor therapy. 

Disclosure: Some study authors declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.  

Reference

Kass MA, Heuer DK, Higginbotham EJ, et al. Assessment of cumulative incidence and severity of primary open-angle glaucoma among participants in the ocular hypertension treatment study after 20 years of follow-up. JAMA Ophthalmol. Published online April 15, 2021. doi:10.1001/jamaophthalmol.2021.0341