Dichoptic multifocal visual evoked potentials identify local retinal dysfunction in age-related macular degeneration

Purpose

To evaluate the ability of multifocal visual evoked potentials (mfVEPs) to identify functional loss in patients with early and exudative age-related macular degeneration (AMD). A dichoptic multifocal stimulus presentation was employed to investigate the regional effects of AMD and the potential diagnostic utility in macular disease.

Methods

MfVEP responses were recorded from 19 unilateral exudative AMD patients with non-exudative (n = 15) or normal (n = 4) presentations in the fellow eye and 28 age-matched controls. Root mean square (RMS) waveforms were pooled across selected EEG channels to produce global field RMS (gfRMS) waveforms. GfRMS amplitudes and response delays were analysed by multivariate linear models, and diagnostic capacity was measured using areas under the curve (AUC) of receiver operator characteristic plots.

Results

The mean gfRMS amplitude of the exudative eye of AMD patients was significantly reduced compared with the controls (?2.03 ± 0.08 dB, t = ?12.9). Fellow non-exudative AMD eyes were less effected but still significantly reduced (?0.84 ± 0.07 dB, t = ?11.5). No significant difference in mean gfRMS delay of AMD eyes across the central 46° was observed. AUC values of 100 ± 0.0 % (mean ± SE) for exudative and 79.7 ± 6.5 % for non-exudative eyes were obtained for response amplitudes.

Conclusion

The study demonstrated that mfVEP identified retinal dysfunction in both exudative AMD and fellow non-exudative AMD eyes, but mostly affecting the macular field. The reduced testing duration and good diagnostic accuracy suggest that dichoptic mfVEPs may be a sensitive tool for monitoring progression in AMD.     

Response to anti-VEGF therapy in patients with subretinal fluid and pigment epithelial detachment on spectral-domain optical coherence tomography

Purpose

To analyse the long-term functional and morphological response of a specific choroidal neovascular membrane (CNV) phenotype to anti-vascular endothelial growth factor (VEGF) therapy.

Methods

Data from 30 eyes of 30 consecutive patients with subretinal fluid (SRF) and fibrovascular pigment epithelial detachment (PED) due to CNV on spectral-domain optical coherence tomography (SDOCT) with a follow-up of at least 20 months were retrospectively collected. Main outcome measures included change in visual acuity, quantitative and qualitative parameters on SDOCT [photoreceptor layer, outer nuclear layer (ONL), choroid, PED, SRF] and on fluorescein angiography (CNV activity). Subjects were divided into responders and non-responders based on morphological and functional aspects.

Results

An average number of 20.23?±?9.9 anti-VEGF injections were administered during a mean follow-up of 40.25?±?13.5 months. Fourteen eyes were categorized as morphological non-responders, 12 as functional non-responders and eight as complete non-responders. Complete non-responders were significantly younger than complete responders (68.5?±?4.5 vs 74.3?±?6.8 years; p?<?0.05) and presented thinner baseline ONL values (68.43?±?15.2 vs103.5?±?32.8 μm; p?<?0.05). Intermediate or large drusen as typical features for age-related macular degeneration (AMD) were less frequently present in complete non-responders; however, this was not statistically significant (62.5 % vs 91.7 %; p?=?0.25).

Conclusions

Our preliminary findings indicate that eyes with the specific SDOCT phenotype with isolated fibrovascular PED and SRF frequently demonstrate non-response to anti-VEGF therapy, and the underlying disease mechanism may be different from AMD. Larger prospective trials are required to validate those results, and to develop strategies to improve the morphological as well as functional outcome.     

Bimonthly injections of ranibizumab for age-related macular degeneration

Purpose

To evaluate the efficacy of bimonthly intravitreal injections of ranibizumab for age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) in a pilot study.

Methods

This study was a prospective, interventional case series. Thirty eyes of 30 patients received prospectively at least three bimonthly intravitreal injections of ranibizumab (0.5 mg/0.05 ml) without loading doses. The best-corrected visual acuity (BCVA) and the central retinal subfield thickness (CRST) were measured before and monthly after the injections.

Results

Twenty-eight patients received the three planned injections; one patient refused the third injection, one patient did not receive the third injection because blood pressure was raised, and one patient received a rescue injection at month 5 because of increased retinal thickness. The mean logarithm of the minimum angle of resolution (logMAR) BCVA was 0.44?±?0.37 before treatment and significantly improved to 0.25?±?0.34 at month 6 (p?p?p?=?0.005). The mean CRST was 360?±?110.8 μm before treatment and decreased significantly to 249?±?57.0 μm at month 12 (p?=?0.025).

Conclusions

Bimonthly injections of ranibizumab may be effective for treating AMD and PCV.     

Factors influencing the exudation recurrence after cataract surgery in patients previously treated with anti-vascular endothelial growth factor for exudative age-related macular degeneration

Purpose

To investigate factors influencing exudation recurrence following cataract surgery in patients already treated with anti-vascular endothelial growth factor (VEGF) agents for exudative age-related macular degeneration (AMD).

Methods

A retrospective review of medical records was performed for patients who underwent cataract surgery and had been previously treated with anti-VEGF for exudative AMD. Visual acuity was examined before surgery and 1 and 6 months after surgery. The time between diagnosis and surgery, and the exudation-free period before surgery were examined and compared between patients who had exudation recurrence and those that did not.

Results

Thirty-nine eyes of 39 patients were included in analyses. The logarithm of the minimum angle of resolution visual acuity was 1.02?±?0.58 and had significantly improved 1 month (0.81?±?0.62, P?P?=?0.001) following surgery. Both the diagnosis-to-surgery period (P?=?0.001) and the preoperative exudation-free period (P?Conclusions Cataract surgery was beneficial in patients previously treated with anti-VEGF for exudative AMD. Our data suggests that cataract surgery should be performed after a sufficiently long exudation-free period to minimize exudation recurrence. But larger prospective studies are required to draw definitive clinical guidelines.     

Comparison of subfoveal choroidal structures in typical neovascular age-related macular degeneration and polypoidal choroidal vasculopathy

Purpose

To evaluate and compare the intrachoroidal structures of eyes with typical neovascular age-related macular degeneration (AMD) with those of eyes with polypoidal choroidal vasculopathy (PCV).

Study design

Retrospective and comparative case series.

Methods

Eighty-four treatment-naïve eyes of 84 patients (22 women and 62 men) with typical neovascular AMD or PCV located in the subfoveal region were studied. Cross-sectional images of the retina and choroid were obtained by swept-source optical coherence tomography (SS-OCT). The horizontal SS-OCT images were analyzed by a manual delineation technique and by a binarization method.

Results

Thirty-nine eyes with typical neovascular AMD and 45 eyes with PCV were studied. Although the subfoveal choroidal thickness (SCT) did not differ significantly between the 2 subtypes (255.1?±?86.7 µm in typical neovascular AMD and 289.2?±?116.5 µm in PCV, P?=?0.29), the ratio of the large choroidal vessel layer (LCVL) thickness to the SCT was significantly larger in the eyes with PCV than in the eyes with typical neovascular AMD (0.863?±?0.084 vs 0.803?±?0.125, P?=?0.023). The binarization method did not find significant differences in the choroidal structure between the 2 subtypes. Multivariate logistic regression analyses found the ratio of the LCVL thickness to the SCT to be the only significantly different factor between typical neovascular AMD and PCV (P?=?0.035).

Conclusion

The intrachoroidal structures of typical neovascular AMD and PCV eyes differ significantly. In eyes with PCV, there seemed to be a greater dilation of the large choroidal vessels.

     

Multifocal electroretinography in type 2 idiopathic macular telangiectasia

Background

To characterize the electroretinographic response of the macula by multifocal electroretinography (mfERG) in patients with type 2 idiopathic macular telangiectasia (MacTel).

Methods

A prospective study of mfERG in patients with type 2 MacTel was conducted from April 2009 to November 2009. mfERGs were recorded using a visual evoked response imaging system (MonElec2, Metrovision, Perenchies, France). The International Society for Clinical Electrophysiology of Vision (ISCEV) guidelines were followed. Patients with type 2 MacTel confirmed by fundus fluorescein angiography without subretinal neovascularisation were included. For recording purposes, 61 stimulus hexagonal elements were used. The first-order kernel mfERG responses were analyzed. Individual mfERG responses for the hexagons were grouped into concentric rings centered on the fovea for analysis (< 2, 5–10, 10–15 and >15°). Student’s t-test and Mann–Whitney U test and linear regression analysis was performed with STATA ver 11.1 (StataCorp, College Station , TX, USA).

Results

Twenty eight eyes of 14 patients and 20 eyes of ten normal controls were included in the study. The mean logMAR visual acuity of the patients was 0.51 (Snellen equivalent 20/63). The mean N1 amplitude (nv/deg²) of patients were significantly reduced compared to controls and were as follows: 8.91?±?14.00 vs 43.44?±?9.55 (p?<?0.0001) in less than 2°, 9.24?±?10.47 vs 22.00?±?3.87 (p?<?0.0001) in 5–10°, 8.57?±?10.02 vs 15.24?±?1.89 (p?<?0.0001) in 10–15°, and 7.03?±?6.52 vs 12.47?±?2.62 in?>?15° (p?<?0.001). The mean P1 amplitude (nv/deg²) was also significantly reduced in patients compared to controls and was as follows: 27.66?±?37.44 vs 96.20?±?12.41 (p?<?0.0001) in less than 2°, 22.61?±?19.38 vs 53.78?±?9.79 (p?<?0.0001) in 5–10°, 18.75?±?20.21 vs 35.22?±?4.16 (p?<?0.001) in 10–15°, and 17.10?±?12.54 vs 25.71?±?3.93 (p?<?0.001). The implicit time of N1 and P1 were also delayed significantly in all the rings. The mean central foveal thickness assessed by optical coherence tomography (OCT) scan was 84.78?±?45.12 μm. There was poor correlation between mfERG amplitudes or implicit times with either the visual acuity or OCT central thickness.

Conclusion

mfERG showed significant reduction in amplitudes and implicit times of the waveforms in patients with type 2 MacTel in all the rings, suggesting a more generalized affection of the macula. The maximum reductions were seen in the <2^o rings. Although there was poor correlation between the visual acuity and the amplitudes a of the waveforms, mfERG is a useful investigative modality for functional assessment of macula in type 2 MacTel patients.     

Clinical results of selective laser trabeculoplasty in silicone oil-induced secondary glaucoma

Background

To analyze the efficacy of selective laser trabeculoplasty (SLT) on silicone oil-induced secondary glaucoma in terms of intraocular pressure (IOP).

Patients and Methods

42 patients (42 eyes) with silicone oil-induced secondary glaucoma were selected, and SLT was performed with 360° of the trabecular meshwork. During the 12-month follow-up, the complications, IOP, and antiglaucoma medication usage were observed.

Results

The mean IOP decreased from 23.1?±?1.9 mmHg before treatment to 18.4?±?3.7 mmHg after treatment (p?<?0.05). Mean number of antiglaucoma medications used for IOP control also decreased from 2.17?±?1.21 to 1.25?±?0.89 (p?<?0.05). The 12-month success rate in the total sample was 59.5 %. The success rate was 60.7 % (17 eyes) and 57.1 % (eight eyes) for phakic and aphakic eyes, respectively (p?>?0.05)

Conclusions

SLT is a safe and effective option for the treatment of patients with silicone oil-induced secondary glaucoma.     

A retrospective evaluation of the effect of hydroxyquinine on RPE thickness

Background

To investigate a possible structural difference in the retina of hydroxychloroquine (Plaquenil)-treated patients as an explanation for the protective effect of this medication against age-related macular degeneration (AMD).

Methods

In this retrospective study, we compared the mean thickness of the retinal outer band (consisting of the Bruch’s membrane and retinal pigment epithelium layer), as measured by optical coherence tomography (OCT), of 54 eyes of 27 hydroxychloroquine-treated rheumatoid arthritis patients (study group), 40 eyes of 20 healthy similar aged individuals (control group I), and 22 eyes of 11 non-hydroxychloroquine-treated rheumatoid arthritis patients (control group II).

Results

The mean thicknesses of the outer band of the retinal pigment epithelium layer was 60.4?±?7.4, 43.3?±?2.7, and 39.7?±?3.6 μm for the study group, control group I, and control group II, respectively. P values for differences in mean thicknesses were < 0.0001 between the study group and each of the control groups, and 0.086 between the two control groups.

Conclusion

Treatment with hydroxychloroquine was associated with increased thickness of the outer band of the retinal pigment epithelium layer. This finding may explain the protective effect of hydroxychloroquine against age-related macular degeneration (AMD).     

Impact of injection techniques on intraocular pressure (IOP) increase after intravitreal ranibizumab application

Purpose

To examine the influence of different intravitreous injection techniques on the short-term intraocular pressure (IOP) in patients with exudative age-related macular degeneration (AMD) receiving 0.05 ml ranibizumab (Lucentis®) in the supine position.

Methods

Forty-five eyes (45 patients, 16 male, 29 female, mean age: 78 years) received intravitreal ranibizumab injections for treatment of exudative AMD (0.05 ml?=?0.5 mg). A total of 31 patients received a standard straight scleral incision, and 14 were injected using the tunneled sclera technique. IOP was measured by Schiøtz tonometry immediately pre-and postoperatively, and the amount of subconjunctival reflux was documented using a semi-quantitative scale. Twenty-three eyes were phakic, and the remaining 22 were pseudophakic. No history of glaucoma was present. The Wilcoxon matched-pairs test was used for comparisons.

Results

The mean preoperative IOP was 22.4?±?5.5 mmHg in the supine position. Immediately after the injection, the IOP increased to 47.9?±?15.1 (range 23–82). The mean difference between preoperative IOP and immediately after the injection was 25.5?±?13.6 mmHg. The mean IOP increase in eyes receiving a standard straight scleral incision was 21.9?±?14.2 mmHg (median 22.3) versus 33.5?±?7.2 mmHg (median 34.7) in the tunneled scleral incision group (p?=?0.001).

Conclusions

IOP increased significantly in a considerable number of patients after receiving 0.05-ml intravitreal ranibizumab injections. This increase was dependent on the intravitreal injection technique and was significantly higher if a tunneled scleral injection was performed.     

Photoreceptor inner and outer segment layer thickness in multiple evanescent white dot syndrome

Purpose

To evaluate the photoreceptor inner and outer segment layer thickness in eyes with MEWDS.

Design

Prospective, non-comparative, observational case series. The follow-up duration was 4 months.

Methods

Four women were diagnosed with unilateral MEWDS. The ages of the patients were 25, 24, 35, and 40 years. The retinal microstructure was assessed by spectral-domain optical coherence tomography (SD-OCT). The thickness of the photoreceptor inner (IS) and outer (OS) segments and sum of them (IS + OS) at the fovea were analyzed.

Results

The visual acuity was reduced in three of four eyes at the acute phase. SD-OCT showed that the border of IS and OS (IS/OS) line and the cone outer segment tips (COST) line in the macula area were not detected in all four eyes. The IS + OS thickness was 50.3?±?5.6 μm and that of the healthy fellow eyes was 73.5?±?7.0 μm (n?=?4 eyes). The thickness of the IS was 27.8?±?2.6 μm and that of the OS was 45.8?±?7.3 μm. In all eyes, there was a spontaneous improvement of the visual acuity. SD-OCT showed a recovery of only the IS/OS line in the macular area, but the COST line was not visible in three cases. The mean IS + OS thickness increased to 56.0?±?7.9 μm (n?=?4), IS?=?26.0?±?2.0 μm (n?=?3), and OS?=?30.1?±?8.7 μm (n?=?3) in the early recovery phase, and to 64.8?±?9.3 μm (n?=?4), IS?=?28.5?±?1.7 μm (n?=?4), and OS?=?36.3?±?7.9 μm (n?=?4) in the late recovery phase. The mean inner and outer segment thickness remained unchanged in the fellow eyes.

Conclusion

Eyes with MEWDS have changes in the photoreceptor microstructures. The change in the IS + OS thickness during the natural recovery course might be due to an increase in the OS length.     

Genetic and clinical factors associated with reticular pseudodrusen in exudative age-related macular degeneration

Backgrounds

Reticular pseudodrusen (RPD) is considered to be a distinct entity from soft drusen and a risk factor for age-related macular degeneration (AMD). In the present study, we investigate the genetic and clinical factors associated with reticular pseudodrusen (RPD) in patients with exudative AMD, including polypoidal choroidal vasculopathy (PCV), typical neovascular AMD, and retinal angiomatous proliferation (RAP).

Methods

The presence or absence of RPD was studied among 408 patients with exudative AMD in at least one eye, and the clinical characteristics of those with RPD were investigated as well as genetic polymorphisms of ARMS2 A69S (rs10490924) and CFH I62V (rs800292). Subfoveal choroidal thickness was also evaluated in a limited number of subjects using the EDI mode of spectral-domain optical coherence tomography.

Results

The prevalence of RPD was significantly higher in RAP eyes than in typical neovascular AMD or in PCV eyes (38.2 % of 26 eyes, 13.6 % of 132 eyes and 0 % of 250 eyes respectively, P?P?P?P?ARMS2 A69S was significantly higher in eyes with RPD than in those without RPD (85.7 % vs 63.8 %, P?=?0.0009), although the frequency of CFH I62V was not significantly different between those with and without RPD. Logistic regression analysis revealed that age (odds ratio [OR]:1.10; 95 % confidence interval [CI]: 1.04–1.18; p?=?0.002), female gender (OR:4.26; 95%CI: 1.72–10.4; p?=?0.002), T-allele at ARMS2 A69S (OR: 3.23; 95%CI: 1.36–7.68; p?=?0.008) and RAP (OR: 4.25; 95%CI:1.49–12.1; p?=?0.007) were risk factors for RPD.

Conclusions

Among eyes with exudative AMD, RPD is more common in eyes with RAP having a thin choroid at the fovea, especially in old, female patients with the risk variant of ARMS2 A69S.     

In diabetic eyes, multifocal ERG reflects differences in function between the nasal part and the temporal part of the macula

Purpose

The purpose of the present study was to compare retinal function between the perifoveal nasal and perifoveal temporal areas of diabetic eyes using multifocalERG (mfERG).

Methods

We included 36 eyes from 27 patients with diabetes (age 58?±?14?years; duration of diabetes 13?±?9?years; HbA_1c 7.1?±?1.8%) and a control group with 18 eyes from 18 healthy subjects (age 57?±?11?years). Retinal thickness was assessed with optical coherence tomography (OCT) in the perifoveal areas corresponding to the summed nasal and temporal inner and outer areas. MfERG amplitude and implicit time were recorded from corresponding areas.

Results

Diabetic eyes showed lower mfERG amplitude in the nasal area than in the temporal area (14?±?6 vs 17?±?7?nV/deg²; p?p?=?0.005). In the control group, there were no significant differences between the two areas.

Conclusion

Diabetic eyes showed lower amplitude and longer implicit time in the nasal area than in the temporal, which might indicate that the nasal area is more vulnerable. These findings may be of importance for evaluation of diabetic maculopathy and outcome after laser treatment.     

Vitrectomy and internal limiting membrane peeling without gas tamponade for myopic foveoschisis

Purpose

To evaluate the efficacy of vitrectomy including internal limiting membrane (ILM) peeling without gas tamponade for myopic foveoschisis (MF).

Method

In this retrospective study, 15 eyes of 13 consecutive patients with MF underwent pars plana vitrectomy and ILM peeling without gas tamponade. The main outcomes were measured using best-corrected visual acuity (BCVA) and central macular thickness (CMT) on optical coherence tomography (OCT).

Result

The mean refractive error was ?11.0?±?8.2 diopters and mean axial length was 30.8?±?2.6?mm. The mean BCVA increased from 0.78?±?0.53 to 0.61?±?0.75 logMAR unit (p?=?0.05), and the mean CMT decreased from 405?±?143?μm to 255?±?47?μm (p?=?0.002) during a follow-up of 11.8?months. OCT showed a complete resolution of the MF, with foveal reattachment in all eyes. Full-thickness macular hole developed in two eyes during follow-up.

Conclusion

ILM peeling without gas tamponade results in favorable anatomical and visual outcomes.     

The influence of axial length on confocal scanning laser ophthalmoscopy and spectral-domain optical coherence tomography size measurements: a pilot study

Purpose

To investigate the influence of axial length on SD-OCT and cSLO size measurements from the Heidelberg Spectralis.

Methods

In this pilot study, eight emmetropic pseudophakic eyes with subretinal visual implant were selected. The axial length was measured in three short (<22.5 mm), three medium (22.51–25.50 mm) and two long (>25.52 mm) eyes. The known size of subretinal implant sensor field (2800?×?2800 μm) was measured on 15 images per eye with cSLO and SD-OCT.

Results

The mean axial length was 20.8?±?0.8 mm in short eyes, 23.3?±?0.4 mm in medium eyes, and 26.3?±?0.5 mm in long eyes respectively. We found in short eyes, in medium eyes and in long eyes a mean value of sensor field size measurements from cSLO of 3327?±?9 μm, 2800?±?9 μm and 2589?±?12 μm and from SD-OCT of 3328?±?9 μm, 2800?±?12 μm and 2585?±?19 μm respectively. The size measurements decreased in SD-OCT and cSLO measurements with longer axial lengths significantly (p?<?0.0001).

Conclusion

The present findings demonstrate accuracy of the scaling in cSLO and SD-OCT measurements of the Heidelberg Spectralis for emmetropic medium eyes. The size measurements from SD-OCT to those from cSLO were approximately equal. Caution is recommended when comparing the measured values of short and long eyes with the normative database of the instrument. Further studies with larger sample sizes are needed to confirm findings.     

Retinal vessel diameter in normal-tension glaucoma patients with asymmetric progression

Purpose

To investigate the longitudinal changes in the central retinal vessel diameter in asymmetric progressive normal-tension glaucoma (NTG) patients.

Methods

This study included 27 patients with bilateral NTG without any systemic vascular disease who showed glaucomatous progression in one eye at the mean follow-up of 24.3 months (range, 18–29 months). Progression was determined by the development of new retinal nerve fiber layer (RNFL) defects or widening of pre-existing defects on red-free RNFL photographs. The central retinal arteriolar equivalent (CRAE) and the central retinal venular equivalent (CRVE) were measured at baseline and at the mean follow-up of 24.3 months. We classified the eyes of each patient as either progressed or stable eyes, and compared the differences and changes in the CRAE and CRVE.

Results

No significant inter-eye difference was observed at baseline in the mean CRAE (167.5?±?22.2 μm vs. 168.2?±?15.5 μm, p?=?0.809) and in the mean CRVE (276.3?±?18.2 μm vs. 281.6?±?21.9 μm, p?=?0.267) between the progressed and stable eyes. There were significant changes in CRAE in the progressed eyes between baseline and 2 years after baseline (from 167.5?±?22.2 μm to 146.9?±?18.0 μm, p?p?=?0.084).

Conclusions

In our series of NTG patients with asymmetric progression, central retinal artery diameter decreased over time in the progressed eyes, whereas no significant decrease in the central retinal artery diameter was seen in the stable eyes.     

Electroretinographic assessment of retinal function during acute exposure to normobaric hypoxia

Background

The current study aimed to investigate retinal function during exposure to normobaric hypoxia.

Methods

Standard Ganzfeld ERG equipment (Diagnosys LLC, Cambridge, UK) using an extended ISCEV protocol was applied to explore intensity–response relationship in dark- and light- adapted conditions in 13 healthy volunteers (mean age 25?±?3 years). Baseline examinations were performed under atmospheric air conditions at 341 meters above sea level (F_IO₂ of 21 %), and were compared to hypoxia (F_IO₂ of 13.2 %) by breathing a nitrogen-enriched gas mixture for 45 min. All subjects were monitored using infrared oximetry and blood gas analysis.

Results

The levels of PaCO₂ changed from 38.4?±?2.7 mmHg to 36.4?±?3.0 mmHg, PaO₂ from 95.5?±?1.9 mmHg to 83.7?±?4.6 mmHg, and SpO₂ from 100?±?0 % to 87?±?4 %, from baseline to hypoxia respectively. A significant decrease (p?<?0.05) was found for saturation amplitude of the dark-adapted b-wave intensity–response function (Vmax), dark-adapted a- and b-wave amplitudes of combined rod and cone responses (3 and 10 cd.s/m²), light-adapted b-wave amplitudes of single flash (3 and 10 cd.s/m²), and flicker responses (5–45 Hz) during hypoxia compared to baseline, without changes in implicit times. The a-wave slope of combined rod and cone responses (3 and 10 cd.s/m²) and the oscillatory potentials were significantly lower during hypoxia (p?<?0.05). A isolated light-adapted ON response (250 ms flash) showed a reduction of amplitudes at hypoxia (p?<?0.05), but no changes were observed for the OFF response.

Conclusions

The results show significant impairment of retinal function during simulated normobaric short-term hypoxia affecting specific retinal cells of rod and cone pathways.     

Inverse pattern of photoreceptor abnormalities in retinitis pigmentosa and cone–rod dystrophy

Purpose

To determine the characteristics of the photoreceptor abnormalities in retinitis pigmentosa (RP) and cone?Crod dystrophy (CRD).

Methods

We evaluated the photoreceptor abnormalities using spectral-domain optical coherence tomography (SD-OCT) in 28 patients with RP and 17 patients with CRD. The OCT images and full-field electroretinograms were obtained from 21 eyes in normal subjects who were age-matched to patients with RP and CRD and served as controls.

Results

Eyes with RP and CRD had markedly decreased rod responses (6.5 and 57.5?% of normal value), maximal responses (9.6 and 51.6?%), cone (16.5 and 25.8?%), and 30-Hz flicker responses (17.8 and 30.1?% of normal value), and their P values were smaller than 0.0003. On comparison of ERG data between RP and CRD, they had statistically significant differences in rod responses (P?<?0.0003) and maximal responses (P?<?0.0003). However, there were no statistical differences in cone response and a weak difference in 30-Hz flicker responses (P?<?0.017). The best-corrected visual acuity was ?0.03?±?0.09 (logMAR, mean?±?standard deviation [SD]) in eyes with RP, but 0.57?±?0.54 in eyes with CRD. SD-OCT showed that eyes with RP had an intact reflective line at the junction between the photoreceptor inner and outer segment (IS/OS) at the fovea, while eyes with CRD had no IS/OS. The extent of the central visual field was correlated with the IS/OS length at the macula in eyes with RP.

Conclusion

The distribution patterns of the IS/OS line help to differentiate between RP and CRD.     

Retinal venous pressure in the non-affected eye of patients with retinal vein occlusions

Background

To measure the retinal venous pressure (RVP) in both eyes of patients with unilateral central retinal vein occlusions and to compare these values to controls.

Methods

The study included 31 patients with unilateral central retinal vein occlusions (CRVO) and 31 controls who were matched by age, sex, and systemic disease. RVP was measured in all patients bilaterally by means of contact lens ophthalmodynamometry, and the RVP measurements of the affected and unaffected eyes of patients were compared to the RVPs of controls. Ophthalmodynamometry is done by applying an increasing pressure on the eye via a contact lens. The minimum force required to induce a venous pulsation is called ophthalmodynamometric force (ODF). The RVP is defined and calculated as the sum of ODF and intraocular pressure (IOP) [RVP = ODF + IOP].

Results

The RVP group means ± SD were as follows: patient’s affected eyes (45.0?±?11.6 mmHg), patient’s unaffected eyes (38.0?±?11.1 mmHg) ,and (17.7?±?6.7 mmHg) in the eyes of controls. The values of RVP, even in the patients unaffected eyes, were significantly higher than in the eyes of controls (P?< 0.001).

Conclusions

In patients with CRVO, the RVP is increased in both the affected as well as in the unaffected contralateral eye.     

Ranibizumab for exudative AMD in a clinical setting: differences between 2007 and 2010

Background/purpose

Visual results of ranibizumab given pro re nata in clinical settings depend greatly from the achievement of the monthly follow-up. In 2007, a previous study performed in our tertiary care showed a mean visual gain of only?+?0.7 ETDRS chart letters, probably because of insufficient number of follow-up visits and injections. We report a second retrospective study of patients whose eyes were treated in the same setting, and whose first injection was performed after April 1 2010. The aim was to check if the changes in the management of AMD patients between 2010 and 2007 achieved better visual results.

Method

One hundred and twenty-two patients (125 eyes) with exudative age-related macular degeneration (AMD) were included. Age, gender, side, type of CNV, VA measured on an ETDRS chart at baseline and at 52 ± 6 weeks, the number of IVT performed, and follow-up visits were recorded. The series was compared to our former series of the year 2007. Results are expressed as means?±?standard deviation. Mann–Whitney’s non-parametric test was used to compare the statistical distribution of the parameters measured. Fisher’s exact test was used for 2?×?2 categorical variables, and the chi-square test for others.

Results

In the 2010 series, the mean visual gain was +6.0?±?11.0 l (?35 to?+?34). During this period, the eyes had 5.0?±?1.8 IVT and 7.8?±?1.4 follow-up visits. No correlation was found between the change in VA and gender, type of CNV, age, or the numbers of IVT and visits. There was a reverse correlation between baseline VA and VA changes (r?=??0.413, p?<?0.0001): i.e., the higher the VA at presentation, the smaller the gain. Comparison between 2010 and 2007 showed that in 2010, patients were older (82.2?±?7.0 vs 78.3?±?7.0 y, p?<?0.0001), had a better baseline VA (60.6?±?12.7 vs 56.1?±?14.6 l, p?=?0.0191) and, despite the reverse correlation between change in VA and VA at presentation, visual results were better: +6.0?±?11.0 vs +0.7?±?11.99 l, p?=?0.0003. In 2010, eyes received more injections: 5.0?±?1.8 vs 3.8?±?1.4 in 2007, p?<?0.0001. However, the series did not differ for the number of visits, gender, side or type of CNV.

Conclusions

In 2010, monotherapy with ranibizumab for exudative AMD achieved better visual results than in 2007 in our clinical setting, despite the treatment of older patients with better baseline VA. This is probably due to the greater number of IVT performed. Alternate strategies, such as “inject and extend” or maintenance therapy, may also account for the better visual results.