Focusing on the contributing factors in the differentiation of diagnosed and undiagnosed primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG), researchers in Japan recently found that PACG was more likely to have been previously diagnosed than POAG during a screening exam. Further, they noted that examination of the anterior segment and visual field may play a larger role in the detection of PACG, and that disc examination may contribute more to POAG detection.
This population-based survey evaluated a cohort of residents 40 years old and older in Kumejima, Japan. PACG and POAG were diagnosed according to the criteria of the International Society of Geographical and Epidemiological Ophthalmology. Significant factors in the differentiation of diagnosed and undiagnosed PACG and POAG were selected from various systemic, ocular, visual functional and fundus planimetric parameters and compared between the two diseases.
The prevalence rates of PACG and POAG were 2.2% and 4.0%, respectively. A greater proportion of PACG cases (34.1%) were previously diagnosed than POAG cases (17.2%). Worse mean deviation on visual field testing (odds ratio (OR) 0.869) and the presence of signs suggestive of previous acute angle closure (OR 4.35) contributed to an established diagnosis of PACG at the time of screening. On the other hand, a greater vertical cup/disc ratio (OR 3.74) contributed with marginal significance to an established diagnosis of POAG at the time of screening.
The study authors concluded that certain assessments are more beneficial in the diagnosis of PACG and of POAG than others, encouraging eye care providers to use this information to their advantage when screening for both diseases.
Iwase A, Sawaguchi S, Araie M. Differentiating diagnosed and undiagnosed primary angle-closure glaucoma and open-angle glaucoma: a population-based study. Ophthalmology. July 30, 2021. [Epub ahead of print].