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Progression of Retinitis Pigmentosa as Measured on Microperimetry: The PREP-1 Study
Mustafa Iftikhar1, Saleema Kherani1, Ramandeep Kaur1
1The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Purpose:
To evaluate yearly progression of retinitis pigmentosa (RP) using microperimetry (MP) performed on Nidek MP1 (NAVIS Software v1.7; Nidek Technologies, Padova, Italy).
Design:
Retrospective longitudinal study.
Participants:
RP patients with consecutive MP tests (using the same test settings).
Methods:
Data were collected as part of the Photoreceptor Cell Death in Retinitis Pigmentosa Retrospective (PREP-1) study. Visual acuity, fixation stability, mean sensitivity, and regional sensitivity were assessed at baseline and at yearly follow-up appointments. Regional sensitivity was calculated based on 2 methods. Method 1 involved topographical division into central macula (CM) and paracentral macula (PM). Method 2 involved functional division into the edge of scotoma (ES) and the seeing retina (SR). Linear mixed-effects models were used to assess the annual rate of change for each parameter, adjusted for disease duration.
Main Outcome Measures:
Annual rate of change of visual acuity, fixation stability, and retinal sensitivities (mean sensitivity and regional sensitivities using methods 1 and 2).
Results:
In total, 75 eyes of 39 patients (median age, 56 y; males, 57%) with a follow-up period ranging from 1 to 4 years were reviewed. Visual acuity at baseline was positively correlated with all retinal sensitivity parameters, most strongly with CM sensitivity (r = 0.545, P < 0.001). There was no change in visual acuity (P = 0.075) or fixation stability (P = 0.371) per year. All retinal sensitivity parameters had a significant decline per year (P < 0.001), with a decline of 0.4 decibel (dB) for mean sensitivity, 0.6 dB for CM, 0.3 dB for PM, 1.3 dB for ES, and 1.1 dB for SR. Method 2 identified the greatest number of cases, with a significant decline in regional sensitivity.
Conclusion:
MP can detect significant changes in regional sensitivity over a 1-year period in patients with RP, even as visual acuity and fixation remain stable. An individualized approach to analyzing retinal sensitivity derived from MP may offer a useful outcome measure for future clinical trials.
Insights
Microperimetry (MP) reveals significant yearly declines in retinal sensitivity for retinitis pigmentosa (RP) patients, despite stable visual acuity and fixation. This highlights MP
Area of Science:
- Ophthalmology and Vision Science
- Retinal Degeneration Research
- Diagnostic Imaging Technologies
Background:
- Retinitis pigmentosa (RP) is a group of inherited retinal diseases that cause progressive vision loss.
- Accurate monitoring of RP progression is crucial for understanding disease trajectory and evaluating potential therapies.
- Microperimetry (MP) is a functional visual field test that assesses retinal sensitivity.
Purpose of the Study:
- To evaluate the yearly progression of retinitis pigmentosa (RP) using microperimetry (MP).
- To assess changes in visual acuity, fixation stability, and retinal sensitivity over time in RP patients.
- To determine the utility of MP in detecting functional changes in RP.
Main Methods:
- A retrospective longitudinal study analyzed data from 75 eyes of 39 RP patients.
- Consecutive MP tests were performed using consistent settings, with data collected from the PREP-1 study.
- Linear mixed-effects models assessed annual changes in visual acuity, fixation stability, and regional retinal sensitivities (mean, central macula, paracentral macula, edge of scotoma, seeing retina).
Main Results:
- While visual acuity and fixation stability remained stable year-over-year, all retinal sensitivity parameters showed significant annual decline (P < 0.001).
- Specific declines per year included: 0.4 dB for mean sensitivity, 0.6 dB for central macula, 0.3 dB for paracentral macula, 1.3 dB for edge of scotoma, and 1.1 dB for seeing retina.
- Functional division of regional sensitivity (edge of scotoma and seeing retina) identified the most significant declines.
Conclusions:
- Microperimetry can detect significant yearly changes in regional retinal sensitivity in RP patients, even when visual acuity and fixation are stable.
- MP demonstrates potential as a sensitive outcome measure for tracking RP progression.
- An individualized analysis of MP-derived retinal sensitivity may be valuable for future clinical trials in RP.
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