Related Experiment Videos
Pattern electroretinogram and spatial contrast sensitivity in primary congenital glaucoma
M S Roy1, M Barsoum-Homsy, N Hanna
1Department of Ophthalmology, Hôpital Ste-Justine, Montreal, Quebec, Canada.
Insights
Pattern electroretinogram (PERG) and contrast sensitivity (CS) show deficits in primary congenital glaucoma (PCG). PERG findings in PCG differ from primary open-angle glaucoma, suggesting distinct disease mechanisms.
Area of Science:
- Ophthalmology
- Neuroscience
Background:
- Primary congenital glaucoma (PCG) is a rare form of childhood glaucoma.
- Early diagnosis and monitoring are crucial for managing PCG and preventing vision loss.
- Pattern electroretinogram (PERG) and spatial contrast sensitivity (CS) are electrophysiological and psychophysical tests, respectively, used to assess visual function.
Purpose of the Study:
- To investigate the temporal and spatial characteristics of PERG and CS in patients with PCG.
- To determine the utility of PERG and CS as diagnostic tools for childhood glaucoma, specifically PCG.
- To compare the PERG findings in PCG with those in primary open-angle glaucoma (POAG).
Main Methods:
- PERGs were recorded in ten patients with PCG and nine age-matched healthy controls.
- PERGs were elicited using phase-alternating checkerboard patterns at various temporal frequencies (2, 4, 16 reversals per second) and spatial checks (30', 60').
- Ophthalmologic evaluations, including visual field testing, were performed on all participants.
Main Results:
- Patients with PCG demonstrated reduced CS compared to controls.
- Significant PERG deficits were observed in PCG patients, particularly at lower temporal frequencies.
- PERG amplitude in PCG patients approached control levels at high temporal frequencies, differing from POAG findings.
Conclusions:
- Reduced PERG amplitude in PCG correlates with decreased CS and visual field defects.
- The spatiotemporal characteristics of PERG deficits in PCG are distinct from those in POAG.
- These differences suggest potentially different underlying mechanisms of retinal ganglion cell dysfunction in PCG versus POAG.
Objective:
The authors investigated the temporal and spatial characteristics of pattern electroretinogram (PERG) and spatial contrast sensitivity (CS) in primary congenital glaucoma (PCG) to determine whether the PERG and CS could be useful tools in the diagnosis of childhood glaucoma, especially PCG.
Participants:
The PERGs were evaluated in eyes from ten patients with PCG and nine age-matched visually normal subjects.
Intervention:
All patients received complete ophthalmologic evaluations including visual field testing.
Main Outcome Measures:
The PERGs were recorded using phase-alternating (2, 4, and 16 reversals per second [rps]) checkerboard patterns (30' and 60' checks).
Results:
The patients with PCG exhibited decreased CS when compared with that of control subjects. Significant PERG deficits also were detected in these patients. However, PERG amplitude in patients with PCG almost reached control subject levels at high (16 rps) temporal frequency. This was true for both 30' and 60' checks. Taken together, these observations on PERG amplitude suggest a more important deficiency of the neural response of the retinal cells at lower temporal frequency (rps) in patients with PCG. This is unlike primary open-angle glaucoma (POAG) in which significant PERG deficits are observed at high temporal frequencies.
Conclusions:
The PERG amplitude is reduced in patients with PCG, and this is consistent with a loss of CS and visual field changes in these patients. However, the spatiotemporal characteristics of the PERG deficits in PCG differ from those of POAG. This could suggest a difference in the mechanisms mediating retinal ganglion cell dysfunction in the two types of glaucoma.