ODs should take a measured approach to glaucoma management that considers the big picture, treat the disease carefully, assess all known risk factors, interpret results carefully, and more than anything else, use clinical evidence as a guide.
Visual field facts
ODs are well aware of visual fields’ varying results. However, false positives are a particular point of concern because they have a significant effect on visual field reliability. Patients may worry that they are underperforming visually. This could cause them to overcompensate and become trigger happy, leading to skewed test results.
This is just one contributing factor to another unfortunate glaucoma fact: determining progression through visual field tests is a challenge. Aside from reliability and variability concerns, rates of visual field change are often inconsistent.
As a result, available classification systems, event analyses, and trend analyses, are used to determine progression.
Clinicians must use their own judgement and apply evidenced-based approaches to their decisions, Dr. Hicks says.
Value of retinal fibers and ganglion cells
A patient’s retinal nerve fiber layer (RNFL) and ganglion cells can prevent data on glaucoma progression. For example, asymmetry in RNFL is common in glaucoma patients; however, increased age itself is not associated with increased RNFL asymmetry.
Furthermore, research indicates that ganglion cell analyses can detect glaucoma. Evidence shows that retinal ganglion cell counts are better than average RNFL thickness when detecting glaucoma with minimal visual field loss.3
And beyond that, the minimum ganglion cell inner plexiform layer (GCIPL) is th best parameter for early perimetric glaucoma detection,4 Dr. Hicks says.
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2. Chung SD, Hu CC, Ho JD, Keller JJ, Wang TJ, Lin HC. Open-angle glaucoma and the risk of erectile dysfunction: a
population-based case-control study. Ophthalmology. 2012 Feb;119(2):289-93.
3. Sihota R, Gupta S, Angmo D. Evaluation of macular ganglion cell analysis compared to retinal nerve fiber layer thickness for
pre-perimetric glaucoma diagnosis. Indian J Ophthalmol. 2018 Apr;66(4):491-493.
4. Xu XY, Lai KB, Xiao H, Lin YQ, Guo XX, Liu X. Comparisons of ganglion cell-inner plexiform layer loss patterns and its diagnostic performance between normal tension glaucoma and primary open angle glaucoma: a detailed, severity-based study. Int J Ophthalmol. 2020 Jan 18;13(1):71-78.