Christophe Valmaggia

Retinal vessel oxygen saturation and its correlation with structural changes in retinitis pigmentosa

To study the influence of retinal structural changes on oxygen saturation in retinitis pigmentosa (RP) patients.

Retinal vessel oxygen saturation in patients suffering from inherited diseases of the retina.

PURPOSEnThe aim of this study was to evaluate the oxygen saturation in patients with inherited diseases of the retina.nnnMETHODSnFundus oximetry images were taken using a retinal vessel analyser (IMEDOS Systems UG, Jena, Germany). Retinal vessel oximetry was performed in 53 eyes of 27 patients suffering from inherited retinal diseases and compared to 22 eyes of 11 healthy controls. The oxygen saturation in all four major retinal arterioles (A-SO2) and venules (V-SO2) were measured and their difference (A-V SO2) was calculated. The data were compared within groups and to controls.nnnRESULTSnBased on V-SO2 values, the rod-cone dystrophy group (66.46%; SD, ± 5.09) could well be differentiated from controls 54.02% (SD, ± 3.04), from cone-rod dystrophies 57.56% (SD, ± 5.66), as well as from inherited maculopathies 58.42% (SD, ± 4.74). The mean A-SO2 in the rod-cone dystrophy group was increased to 98.96% (SD, ± 6.06, p<0.014), while in the cone-rod group and in the maculopathy group it was 92.75% (SD, ± 3.75), respectively 94.44% (SD ± 4.85), closer to the normal values (92.68%; SD, ± 3.53, p>0.05). The A-V SO2 difference, as an indirect indicator for retinal oxygen use, was reduced in the rod-cone patients, however only when the controls were taken into account (p=0.01).nnnCONCLUSIONnThis is to our knowledge the first study which proposes the retinal vessel oximetry to be a sensitive measure for differentiating rod-cone dystrophy patients not only from controls, but also from patients with other inherited retinal dystrophies.

Metabolic and functional changes in retinitis pigmentosa: comparing retinal vessel oximetry to full-field electroretinography, electrooculogram and multifocal electroretinography

To determine a relationship between the retinal vessel saturation alterations and the residual retinal function measured by means of full‐field electroretinography (full‐field ERG), electrooculogram (EOG) and multifocal electroretinography (mfERG) in patients with retinitis pigmentosa (RP).

The price for reduced light toxicity: Do endoilluminator spectral filters decrease color contrast during Brilliant Blue G–assisted chromovitrectomy?

BackgroundVitreoretinal surgeons have been slow to adopt the use of spectral filters for endoillumination to reduce retinal light toxicity. This study shows that spectral filters can be used without a loss in color contrast during brilliant blue G chromovitrectomy.MethodsTo evaluate the influence of intra operative spectral light filters on perceivable contrast during Brilliant Blue G chromovitrectomy, a prospective, observational clinical study was carried out on 59 consecutive Brilliant Blue G chromovitrectomy interventions in 59 patients admitted for macular holes, macular pucker or vitreomacular traction syndromes. Subsequent to peeling of the internal limiting membrane, six different illumination modes were enabled consecutively: mercury vapor, mercury vapor/xenon, and xenon followed by xenon combined with an amber, green or yellow spectral filter. Main outcome measure was the chromaticity spread between stained internal limiting membrane and unstained retina as a measure for the color contrast perceived by the human eye.ResultsMean chromaticity scores were similar for all light sources: mercury vapor 7.97, mercury vapor/xenon 7.96 (pu2009=u20090.96), and xenon 7.41 (pu2009=u20090.55). Compared to xenon, the additional use of endoillumination spectral filters did not change contrast recognizability: Chromaticity scores were 9.38 for the amber filter (pu2009=u20090.13), 6.63 for the green and 7.02 for the yellow filter (pu2009=u20090.37 and 0.64, respectively). When comparing the different filters head-to-head, the amber filter was superior to the green filter (pu2009=u20090.03), while the yellow was intermediate and not significantly different from either the amber (pu2009=u20090.08) or the green filter (pu2009=u20090.51).ConclusionsColor contrast perceptibility during Brilliant Blue G assisted chromovitrectomy is similar with mercury vapor, mercury vapor/xenon or xenon light sources. Spectral filters do not decrease color contrast recognizability. Head-to-head comparison shows a significant advantage for the amber over the green filter with respect to contrast generation, the yellow filter is intermediate. As spectral filters are known to greatly reduce retinal light toxicity, we suggest donor eye studies to validate whether the amber filter should be generally recommended for Brilliant Blue G chromovitrectomy.

Reduced metabolic function and structural alterations in inherited retinal dystrophies: investigating the effect of peripapillary vessel oxygen saturation and vascular diameter on the retinal nerve fibre layer thickness

To evaluate the relationship between the peripapillary metabolic alterations [retinal vessel Oximetry (RO)] and the structural findings [retinal vessel diameter and retinal nerve fibre layer thickness (RNFL)] in patients with inherited retinal dystrophies (IRD).

Contrast recognizability during brilliant blue G - and heavier-than-water brilliant blue G-assisted chromovitrectomy: a quantitative analysis.

Purpose:u2002 To evaluate the potential of heavier‐than‐water brilliant blue G (BBG‐D20) to stain the internal limiting membrane (ILM) during chromovitrectomy.

Preserved functional and structural integrity of the papillomacular area correlates with better visual acuity in retinitis pigmentosa

PurposeLinking multifocal electroretinography (mfERG) and optical coherence tomography (OCT) findings with visual acuity in retinitis pigmentosa (RP) patients.DesignProspective, cross-sectional, nonintervention study.SubjectsPatients with typical RP and age-matched controls, who underwent SD-OCT (spectral domain OCT) and mfERG, were included.MethodsMfERG responses were averaged in three zones (zone 1 (0°–3°), zone 2 (3°–8°), and zone 3 (8°–15°)). Baseline-to-trough- (N1) and trough-to-peak amplitudes (N1P1) of the mfERG were compared with corresponding areas of the OCT. The papillomacular area (PMA) was analyzed separately. Correlations between best-corrected visual acuity (BCVA, logMAR) and each parameter were determined.Main outcome measuresComparing structural (OCT) and functional (mfERG) measures with the BCVA.ResultsIn RP patients, the N1 and N1P1 responses showed positive association with the central retinal thickness outside zone 1 (P≤0.002), while the central N1 and the N1P1 responses in zones 1, 2, and 3—with the BCVA (P≤0.007). The integrity of the IS/OS line on OCT showed also a positive association with the BCVA (P<0.001). Isolated analysis of the PMA strengthened further the structure–function association with the BCVA (P≤0.037). Interactions between the BCVA and the OCT, respectively, the mfERG parameters were more pronounced in the RP subgroup without macular edema (P≤0.020).ConclusionIn RP patients, preserved structure–function of PMA, measured by mfERG amplitude and OCT retinal thickness, correlated well with the remaining BCVA. The subgroup analyses revealed stronger links between the examined parameters, in the RP subgroup without appearance of macular edema.

Terson syndrome in aneurysmal subarachnoid hemorrhage—its relation to intracranial pressure, admission factors, and clinical outcome

BackgroundA large number of reports have not been able to clarify the pathophysiology of Terson syndrome (TS) in aneurysmal subarachnoid hemorrhage (aSAH).MethodsProspective single-center study on aSAH patients. Fundoscopic and radiological signs of TS were assessed. The opening intracranial pressure (ICP) in patients who required a ventriculostomy was recorded with a manometer.ResultsSix out of 36 included patients had TS (16.7xa0%), which was associated with unfavorable admission scores. Twenty-nine patients (80.5xa0%) required ventriculostomy; TS was associated with higher ICP (median, 40 vs. 15 cm cmH2O, pu2009=u2009.003); all patients with TS had pathological ICP values of >20xa0cmH2O. Patients with a ruptured aneurysm of the anterior cerebral artery complex were ten times as likely to suffer from TS (OR 10.0, 95xa0%xa0CI 1.03–97.50). Detection of TS on CT had a sensitivity of 50xa0%, a specificity of 98.4xa0%, a positive predictive value of 83.3xa0%, and a negative predictive value of 92.4xa0%. Mortality was 45 times as high in patients with TS (OR 45.0, 95xa0%xa0CI 3.86–524.7) and neurologic morbidity up until 3xa0months post-aSAH was significantly higher in patients with TS (mRS 4–6; 100 vs. 17xa0%; pu2009=u2009.001).ConclusionsOur findings demonstrate an association between raised ICP and the incidence of TS. TS should be ruled out in aSAH patients presenting comatose or with raised ICP to ensure upfront ophthalmological follow-up. In alert patients without visual complaints and a TS-negative CT scan, the likelihood for the presence of TS is very low.

Prominent Optic Disc Featured in Inherited Retinopathy

Background We investigated the relationship between prominent optic disc (POD) and inherited retinal dystrophy (IRD). Patients and Methods A cross-sectional consecutive study was performed in 10 children and 11 adults of 7 non-related families. We performed clinical phenotyping, including a detailed examination, fundus autofluorescence, and colour fundus and OCT imaging. Genetic testing was subsequently performed for all family members presenting retinal pathology. Results In 4 members of a 3-generation family, hyperfluorescent deposits on the surface of POD were related to a p.(L224M) heterozygous mutation in BEST1. In the second family, one member presented deposits located on the surface on hyperaemic OD and a compound p.(R141H);(A195V) mutation in BEST1. In the third family, POD was observed in father and child with early onset cone-rod dystrophy and a novel autosomal recessive p.(W31*) homozygous mutation in ABCA4. In the fourth family, POD with mulberry-like deposits and attenuated vessels were observed in a 7-year old girl, with a mutation in USH1A, and with early onset rod-cone dystrophy, associated with hearing loss. In the fifth family, blurry OD with tortuous vessels was observed in 4 consanguineous female carriers and a hemizygous boy with a p.(R200H) mutation in the X-linked retinoschisis RS1. In the sixth family, a mother and her son were both affected with POD and attenuated peripapillary vessels, and presented with a p.(Y836C) heterozygous mutation in TOPORS, thus confirming autosomal dominant RP. In the seventh family, in 3 family members with POD, compound p.(L541P;A1038u2009V);(G1961E) mutations in ABCA4 confirmed the diagnosis of Stargardt disease. Conclusions A variety of OD findings are found in a genetically heterogeneous group of IRDs. In the presence of POD, an inherited progressive photoreceptor disease should be ruled out.

Higher retinal vessel oxygen saturation: investigating its relationship with macular oedema in retinitis pigmentosa patients

PurposePrimary objective—to investigate the effect of retinal vessel oxygen saturation (SO2) on macular oedema (ME) in retinitis pigmentosa (RP) patients. Secondary objective—to link the presence of ME to metabolic (oxygen saturation of retinal vessels, SO2), functional (multifocal electroretinography, mfERG) and structural (Spectral Domain Optical Coherent Tomography, SD-OCT) alterations in RP.DesignProspective, cross-sectional, non-interventional study.SubjectsPatients with typical RP (Nu2009=u200937) and controls (Nu2009=u200919), who underwent retinal vessel Oximetry (RO), SD-OCT and mfERG, were included.MethodsA computer-based program of the retinal vessel analyser unit (IMEDOS Systems UG, Jena, Germany) was used to measure SO2. We evaluated the mean SO2, in all major retinal arterioles (oxygen saturation in retinal arterioles, A-SO2, %) and venules (oxygen saturation in retinal venules, V-SO2, %). MfERG responses were averaged in zones (zone 1 (0–3°), zone 2 (3–8°) and zone 3 (8–15°)) and compared to corresponding areas of the OCT. The effect of ME on SO2 was evaluated dividing the RP in two subgroups: with clinical appearance of ME (ME-RP) and without it (no-ME-RP).Main outcome measuresParallel recording and juxtaposition of metabolic (SO2) to structural (OCT) and functional-(mfERG) measures. Mean (u2009±u2009SD) A-SO2 and V-SO2 were higher in no-ME-RP (96.77% (±6.31) and 59.93% (±7.76)) and even higher in the ME-RP (99.82% (±6.21) and 65.63% (±7.63)), compared to controls (93.15% (±3.76) and 53.77% (±3.70), pu2009≤u20090.006).ResultsThe subgroup ME-RP differed significantly from the subgroup no-ME-RP by increased A-SO2 and V-SO2, pu2009≤u20090.026. The presence of ME confirmed a different relationship between the altered SO2 and the vessel diameters, against the functional and structural parameters.ConclusionBased on our results, the presence of macular oedema indicates a tendency toward greater alteration of the metabolic function in RP patients.