Gene variant isolated in glaucoma progression

FORT LAUDERDALE, Fla. — The progression of glaucoma may be influenced by the presence of the myocilin TIGR/MYOC mt.1 variant, according to a study presented here at the annual meeting of the Association for Research in Vision and Ophthalmology.

George Spaeth, MD, and colleagues wanted to evaluate the applications of the quantitative disc and field grading approaches for monitoring the course of glaucoma and to examine if information from genotyping for the myocilin TIGR/MYOC mt.1 variant influences the data.

The study looked at 149 patients who were identified as having primary open-angle glaucoma based on characteristic criteria. Patients with end-stage glaucoma were excluded. The amount of disc and field damage was measured upon entry into the study and every 5 years for an average of 15 years. Researchers used 8-point scales to quantify the amount of damage, known as Disc Damage Likelihood Scales and Field Damage Likelihood Scales. Genotyping was performed separately in a masked fashion.

The study found that the progression of glaucoma appeared to be influenced by the presence or absence of the mt.1(+) variant, which was present in about 15% of the patients. Throughout 6 to 10 years, patients with the variant showed a 20% progression in their glaucomatous symptoms vs. a 10% progression in those without the variant. Throughout 16 to 20 years, those with the variant showed a 63% progression, while those without showed a 30% progression.

Progressive damage was most clearly demonstrated using the combined disc/field system, Dr. Spaeth said.