Pattern Electroretinogram in Glaucoma Suspects with Signs of Conversion: Diagnosis, Assessment, and Monitoring...

The purpose of this case report was to describe a case of a 61-year-old female glaucoma suspect with signs of conversion into early glaucoma. Treatment with prostaglandin analog drops was started.

A 61-year-old female presented with worsening vision in the left eye, elevated intraocular pressure (IOP) of 25 mm Hg in the right eye and 21 mm Hg in the left eye. Humphrey visual field tests showed borderline glaucomatous changes, but pattern electroretinogram (PERG) confirmed objective retinal ganglion cell (RGC) dysfunction in both eyes. Prostaglandin analog drops were offered to be used daily, but the patient preferred to use the drops 3 times per week. PERG was conducted during her next 3 follow-up visits, demonstrating reductions of the IOP lowering effects on PERG parameters when the drops were not instilled consistently. Estimated RGC count significantly increased after IOP lowering treatment.

The effects of the prostaglandin analog treatment have demonstrated improvements in PERG parameters, demonstrating a restoration of RGC function and an increase in the estimated RGC count, based on the combined structure-function index. However, when the treatment was not applied consistently as prescribed, and when longer periods of nontreatment occurred, PERG parameters transiently deteriorated, demonstrating the presence of a transient RGC dysfunction state. PERG demonstrates the potential in monitoring the effectiveness of IOP lowering treatment in newly diagnosed subjects for not only chronic IOP elevation, but for transient IOP elevation detections as well. This could be mostly due to either lack of adherence, skipping treatment, delayed access to prescription refills, or missing timely drop instillations due to forgetfulness or travel.