Clinicians often need to decide between 10-2 or 24-2 visual field (VF) tests when evaluating patients with glaucoma who present with optic disc features as varied as notching of the neuroretinal rim, disc hemorrhages, and atrophic halo.
An American Journal of Ophthalmology study demonstrates unique patterns and degrees of central VF loss based on 4 glaucomatous optic disc phenotypes; focal ischemic (FI), generalized cup enlargement (GE), myopic glaucomatous (MY), and senile sclerotic (SS). The cross-sectional analysis was comprised of 448 eyes of 309 patients; 94 of whom were glaucoma suspects and 354 diagnosed with early to moderate glaucoma. No significant differences existed between phenotypes in regard to intraocular pressure, sex, or spherical equivalent.
“The present study demonstrated that 65% of eyes with mild glaucoma had abnormal 10-2 VF test results and central VF was more affected in the FI group compared to other glaucomatous optic disc phenotypes,” the researchers explained. “Although the foveal sensitivities were similar among the phenotypes, FI, MY and SS groups had proportionately more eyes with abnormal points in most central 4 and 16 points of 10-2 VF compared to GE group.”
Previous studies examining VF defect patterns among optic disc phenotypes used 24-2 VF and did not fully evaluate the central region. In this analysis, investigators directed attention to 10-2 VF with its additional points of measure in the central 10° of view. In the glaucoma suspect and mild glaucoma categories, they found defects in 10-2 VFs more commonly for subjects with FI and MY phenotypes even though no significant differences were found with 24-2 VF.
For subjects with mild glaucoma, abnormal 10-2 VF results were lowest for the GE phenotype (44.4%), and highest in the FI phenotype (79.2%), P =.013. “Notably, patients in the FI group of the current study were more likely to have central VF abnormalities especially in early stages of the disease, which underscores the importance of clinically evaluating the optic disc phenotypes,” the study authors wrote.
Researchers also analyzed VF defect patterns. In subjects with suspected or mild glaucoma, the arcuate-like pattern was the most common shape of visual field loss shown in the 10-2 VF, regardless of phenotype. Also, more losses were generally found in the superior hemifield.
Investigators suggest that patients with FI or MY optic disc phenotypes can benefit from being tested with both 10-2 and 24-2 VF, especially in the early stages of glaucoma.
Subjects for this analysis were recruited from 2 other studies. The first is Diagnostic Innovations in Glaucoma Study (DIGS) based at University of California, San Diego (UCSD). The second subject pool arose from the African Descent and Glaucoma Evaluation Study (ADAGES), a collaborative project of UCSD Hamilton Glaucoma Center, Columbia University Irving Medical Center Edward S. Harkness Eye Institute in New York, and the University of Alabama at Birmingham Department of Ophthalmology.
Disclosure: Several study authors declared affiliations with medical equipment and device manufacturers, and pharmaceutical companies. Please see the original reference for a full list of authors’ disclosures.
Ekici E, Moghimi S, Hou H, et al., Central visual field defects in patients with distinct glaucomatous optic disc phenotypes. Am J Ophthalmol. 2020; Published online October 28, 2020. doi: 10.1016/j.ajo.2020.10.015.