Multiple Rings or Arcs of Hyperautoflourescence in Different Retinitis Pigmentosa Phenotypes

Abstract

 

Purpose

 

To characterize retinal structure and function in retinitis pigmentosa (RP) phenotype patients with multiple rings or arcs of hyperautofluorescence.

 

Methods

 

Fifty-nine patients were divided into three groups according to peripheral patterns seen on 55° fundus autofluorescence (FAF) and optical coherence tomography (OCT) imaging (Heidelberg Engineering Spectralis, Germany), in addition to central FAF ring or patch. Group A presented with additional peripheral rings, group B with arcs and group C with no peripheral hyperautofluorescence. Full-field ERG was performed in 35 patients according to ISCEV standard. Rod and cone response amplitudes were averaged between both eyes and expressed as percentages of lower normal limit (5th percentile). Targeted manual microperimetry (MP1, Nidek, Italy; n=5) were performed across fovea and peripheral hyperautofluorescent border.

 

Results

 

Peripheral rings were observed in 12% (7/59) and arcs in 20% (12/59) of RP phenotype patients with various types of inheritance (Fig. 1). Average age of patients in groups A-C was 45, 51 and 43 years and was not significantly different. Average disease duration (years since onset of nyctalopia) in groups A and B was significantly lower than in group C (5 and 7 years vs. 22 years, respectively; p<0.05). Average rod response amplitudes were 49%, 20% and 2%, and average cone response amplitudes were 54%, 25% and 16% of lower normal, respectively (p<0.05 except for cone response between B and C). Microperimetry revealed on average of 8 dB increase of retinal sensitivity outside of peripheral hyperautofluorescent borders and OCT in that area showed preserved photoreceptor layer. In one patient with dominant RP expansion of hyperautofluorescent ring was observed in duration of one year (Fig. 2).

 

Conclusions

 

Peripheral rings or arcs of hyperautofluorescence were seen in 32% of patients with RP phenotype with various types of inheritance. Peripheral rings were associated with peripherally preserved retina and could represent early stage of disease or specific pattern of progression.

 

 

Figure 1. Types of inheritance in RP phenotype patients with peripheral rings or arcs of hyperautofluorescence. Below are examples of FAF images.

 

 

Figure 2. MP and OCT revealed preserved function and structure outside of peripheral hyperautofluorescent borders.

 

Keywords: 696 retinal degenerations: hereditary • 648 photoreceptors • 550 imaging/image analysis: clinical