Chromatic Full-Field Stimulus Thresholds in Patients with Treatment-Naive Age-Related Macular Degeneration

Abstract

Purpose To evaluate retinal sensitivity using chromatic full-field stimulus thresholds (FST) in patients with treatment naive exudative age-related macular degeneration (e-ARMD) before and during the first intravitreal anti-vascular endothelial growth factor (anti-VEGF) treatment. Patients and Methods After general ophthalmological examinations to diagnose patients with e-ARMD the FST, the central foveal thickness (FCt) and the visual acuity were assessed in 20 eyes of 20 patients during this prospective study. Examinations were performed before and during the first treatment series with three intravitreal anti-VEGF injections. Normal values for FST were assessed in 19 eyes of 19 healthy subjects. Results were analyzed using Student’s two-tailed t -test and Pearson’s correlation coefficients between all functional parameters. Results At baseline and before the 1st intravitreal anti-VEGF treatment, a moderately significant negative correlation between VA and FCt was found in the e-ARMD group (p = 0.02, r = −0.45 and p = 0.03, r = −0.45), respectively. After the 2nd intravitreal anti-VEGF injection, no significant correlation between VA and FCt was found (p = 0.12). However, a significant correlation between FCt and blue FST was evident (p = 0.04, r = 0.4). After the 3rd intravitreal anti-VEGF treatment, there was no correlation evident between VA and FCt (p = 0.31) but a high significant correlation between FCt and FST using red (p = 0.01, r = 0.53), green (p = 0.002, r = 0.6) and blue light (p = 0.007, r = 0.66). Conclusion During anti-VEGF treatment in patients with e-ARMD, the FST test showed higher significant correlations with the morphology measured by FCt, as it is the case for VA. These findings support that the FST test might serve as a valuable diagnostic tool for monitoring patients with e-ARMD and enhance functional assessment of retinal function under treatment with anti-VEGF.

Full-field stimulus threshold testing: a scoping review of current practice

“…This is consistent with the FST having been initially developed expressly for this low vision patient population [ 1 ]. Non-IRD populations in which FST has been performed includes diabetic retinopathy [ 41 , 44 ], age-related macular degeneration [ 1 , 45 ] and one study in only visually healthy controls [ 46 ].…”

ISCEV and IPS guideline for the full-field stimulus test (FST)

“…A white stimulus is produced by using a broadband white light with a colour temperature of 6500 K [ 29 , 31 , 36 ]. Short wavelength (blue) and long wavelength (including red) stimuli can be produced using a range of LEDs [ 1 , 2 , 5 , 27 , 30 , 34 , 35 , 50 ]. Short wavelength LEDs with wavelengths between 444 and 470 nm and longer wavelength LEDs with wavelengths between 538 and 670 nm have been used.…”

“…The strategies chosen for FST balance speed and accessibility. A majority of studies report a 4–2 staircase thresholding [ 1 , 2 , 24 , 29 , 31 , 35 , 42 , 43 ], though the number of reversals or steps to final thresholding vary in the literature. Those that report the methodology in the literature may be unaware of commercial proprietary implementation of the thresholding algorithm and may be reporting the previously published method of a 4–2 staircase which may not the method implemented in proprietary software.…”

“…The algorithm for sequential presentation of stimuli should be specified [ 1 , 2 , 24 , 29 , 31 , 35 , 42 , 43 ]. The observer or patient should be instructed clearly to optimise compliance and reliability of measurements.…”

Comparison of Full-Field Stimulus Threshold Measurements in Patients With Retinitis Pigmentosa and Healthy Subjects With Dilated and Nondilated Pupil

“… 11 Additionally, in cases other than IRD, attempts have been made to use FST as a diagnostic tool. 12 A survey of RP patients with RPE-65 mutations showed that FST is used to evaluate these patients in 36% of centers in Europe. 13 …”