Eric Troeger

Correlation between macular morphology and sensitivity in patients with retinitis pigmentosa and hyperautofluorescent ring.

PURPOSE To assess the correlation between retinal morphology and function in patients with retinitis pigmentosa (RP) using spectral domain optical coherence tomography (SD-OCT), fundus autofluorescence imaging (FAF), and fundus-related perimetry and to use coregistration of data sets to achieve high-resolution structure-function correlation of human macula. METHODS Twelve patients with RP and hyperautofluorescent parafoveal ring in FAF imaging were tested. Ophthalmological examination, static and kinetic fundus-related perimetry, and SD-OCT were performed. Custom software allowed coregistration of fundus-related perimetry, SD-OCT, and FAF data sets. RESULTS A high correlation between retinal sensitivity and outer retinal thickness was observed (ρ = 0.72, P < 0.0001). The median retinal sensitivity over the central circular area of normal autofluorescence was significantly higher when compared with the area over the surrounding hyperautofluorescent ring and to the area outside the ring (H = 34.2, P < 0.0001). The outer retina at the site where kinetic stimuli were perceived was better preserved and had higher retinal thickness, corresponding to higher sensitivity (H = 289, P < 0.0001). The site of the hyperautofluorescent ring correlated in SD-OCT scans with a zone of impaired integrity of the photoreceptor layer (ρ = 0.67, P = 0.0003). CONCLUSIONS Retinal sensitivity to static and kinetic stimuli correlates better with outer than with overall retinal thickness. The hyperautofluorescent ring in FAF represents a transition zone from relatively well-preserved to abnormal retinal morphology and function, rendering FAF imaging a clinically significant tool for assessing the severity and progression of dysfunction in RP patients. Accurate coregistration of different modalities drastically increases the power of structure-function correlation studies and allows consistent associations to be drawn.

Early Visual Symptom Patterns in Inherited Retinal Dystrophies

The present retrospective study compared initial visual symptom patterns in inherited retinal dystrophies (IRD) on the basis of records of 544 patients diagnosed with a wide variety of IRD at the Tuebingen University Eye Hospital from 2005 to 2008. Age at first onset of symptoms was noted, and the following clinical data were analyzed: visual acuity (VA), night vision disturbances, photophobia, onset of visual field defects, best corrected VA, and types of visual field defects. Median age at visual symptom onset was defined with 25th and 75th percentiles and compared in 15 IRD types. The main trends in VA changes in retinitis pigmentosa and cone-rod dystrophies were identified. This study was the first to combine disease history and clinical data analysis in such a wide variety of IRD. It showed that patterns of initial symptoms in IRD can provide extra clues for early differential diagnosis and inclusion of IRD patients in clinical trials.

Visual acuity changes in cone and cone-rod dystrophies

Citation information: Prokofyeva E, Troeger E, Bernd A & Zrenner E. Visual acuity changes in cone and cone‐rod dystrophies. Ophthalmic Physiol Opt 2011. doi: 10.1111/j.1475‐1313.2011.00883.x

Correlation Between Spectral Domain OCT Retinal Nerve Fibre Layer Thickness and Multifocal Pattern Electroretinogram in Advanced Retinitis Pigmentosa

Our aim is to assess the correlation between retinal nerve fibre layer thickness and ganglion cell function by electrophysiological means in advanced retinitis pigmentosa (RP) patients. A prospective observational case–control study enrolled 12 RP patients (age average 44 ± 14 years) with concentric visual field loss (≤10o) and 12 healthy age-matched control for testing. The peripapillary retinal nerve fibre layer (RNFL) thickness was assessed by spectral domain optical coherence tomography. The VERIS system was used to record multifocal pattern electroretinograms (mfPERG), a measure of inner retinal functional output. Amplitudes of P1N2 component were 42 ± 14, 53 ± 25 and 42 ± 17 nV within temporal superior, temporal, and temporal inferior region in RP, and 174 ± 52, 171 ± 46 and 144 ± 15 nV respectively in the control group (p 0.05). The diminution of photoreceptors sensory inputs in advanced RP patients corresponds with reduced amplitudes in mulitifocal pattern electroretinogram, although RNFL measurements indicate no detectable loss of RGC.

An integrated software solution for multi-modal mapping of morphological and functional ocular data

Various morphological and functional techniques for retina examination have been established in the recent years. Although many examination results are spatially resolved and can be mapped onto data originating from other modalities, usually only data from one modality is analyzed by a clinician at a time. This is mainly because there is no software available to the public that enables the registration of structure and function in the clinical setting. Therefore we developed an integrated mapping application that allows the registration and analysis of morphological data (fundus photography, optical coherence tomography, scanning laser ophthalmoscopy images, and GDx thickness profiles) and functional data (multifocal electroretinography, multifocal pattern electroretinography, perimetry, and microperimetry). To obtain quantitative data that can be used for clinical trials and statistical analyses, extraction routines for morphological parameters — such as retinal layer thicknesses and measures of the vascular network — have been integrated. Global, regional and point-specific data from registered modalities can be extracted and exported for statistical analyses. In this article we present the implementation and examples of use of the developed software.

The Special Electrophysiological Signs of Inherited Retinal Dystrophies

The study aim was to analyze the electrophysiological signs of inherited retinal dystrophies (IRD). Full-field and multifocal (mf) electroretinography (ERG) was analysed in three groups: 21 normal subjects, 21 randomly selected IRD patients, and 21 patients randomly selected from each of eleven IRD groups. As a result, median, 5-95 and 25-75 interquantile intervals of each full-field and mfERG parameter were estimated for each of the above mentioned groups and compared using a Kruskal-Wallis test. Quantitative and qualitative criteria defined in this study will improve the precision of differential diagnosis, the detection of IRD severity, and the efficacy of treatment. The quantitative and qualitative characteristics of ERG values, established in this study, can be further applied to the creation of software that will allow the automatic classification of the recording into a specific disease and degree of severity.

Multimodal multidimensional imaging for visual system status assessment

Non-invasive optical methods that enable in vivo or in situ visualization of tissue components are of particular relevance in ophthalmology, as they can provide key information about the relationship between the structure and function of the visual system. In this paper we present a semiautomated multimodal imaging tool for co-registration of images of retinal structure and its function, based on point correspondence. Decision support analysis was applied to define significant features for the multimodal mapping system, using a set of 1500 subjects who were affected by blindness associated hereditary retinal dystrophies. Additionally, the developed software was tested by two experienced observers using data from 25 subjects. Inter-observer and intra-observer reliability was determined. We conclude that semi-automated multimodal mapping could be a promising new tool for an individualized visual system status assessment that can be applied for the early diagnosis of blindness associated diseases. Moreover, this mapping approach should prove particularly appropriate for studying pathophysiology in inherited blindness associated diseases.