Electrophysiologic evaluation of retinal function in patients with psoriasis and vitiligo

Purpose

To investigate the relation between psoriasis and vitiligo with the electrophysiologic function of the retinal photoreceptors.

Methods

Patients with psoriasis or vitiligo referred for PUVA therapy were enrolled. Complete eye examination was performed. Patients with any drug or familial history or abnormal eye examination that might affect the retinal function were excluded. Standardized full-field electroretinogram (ERG) elicited with Ganzfeld stimuli using the commercial ERG system (Retiport32; Roland Consult) according to International Society for Clinical Electrophysiology of Vision guidelines was performed. The outcome measures were the difference between the mean rod response, standard combined response, single-flash cone response and 30-Hz flicker wave amplitudes of the patients and normal population.

Results

Seventy-six eyes of 38 patients (vitiligo: 21; psoriasis: 17) and 40 eyes of 20 normal subjects were enrolled in this study. The mean age of patients was 31.3 ± 11.3 years (range 16–54 years). Twenty-two patients (58 %) were female. The mean rod response b-wave, standard combined a- and b-waves, single-flash cone response b-wave and the 30-Hz flicker (N1-P1) amplitudes were significantly lower than the normal population in the same range of age as the study group. There was no significant difference between the patients with vitiligo and those with psoriasis in all wave amplitudes (P = 0.094).

Conclusion

This study showed that overall retinal electrophysiologic function in patients with vitiligo or psoriasis is significantly impaired compared with normal population, independent of age and sex.     

Full-field electroretinography under general anesthesia in retinoblastoma

Purpose

To investigate the electrical responses of the retina in retinoblastoma (RB), by recording full-field electroretinography (ERG) under general anesthesia.

Methods

The ERG was recorded using Ephios hand-held portable ERG system, according to International Standards for Clinical Electrophysiology of Vision. Forty-eight eyes of 43 cases and 33 eyes of 33 controls were enrolled. The cases were classified based on international intraocular retinoblastoma classification (IIRC). Forty-eight eyes of cases were divided into 30 cases with active RB and 18 cases with regressed RB.

Results

The amplitudes of a- and b-waves were decreased as compared to controls in all subgroups. The implicit times of all RB patients from group A to C differed statistically from controls (p value < 0.05) except for single-flash rod response. The ERG waveforms in group E eyes were non-recordable. The comparison of ERG parameters between active and regressed groups (IIRC groups A and B) was statistically insignificant. Single case follow-up of unilateral RB after systemic chemotherapy showed improvement in amplitudes compared to baseline parameters.

Conclusions

Reduced amplitudes and delayed implicit times were noted in advanced disease. The ERG of RB cases did not follow any specific pattern of waveform. ERG appears to be a dynamic parameter to observe changes following treatment for RB. Although ERG is not a diagnostic test for RB, it can be used as a complementary test to assess the residual retinal function in RB eyes.     

Contribution of N-methyl-dl-aspartic acid (NMDA)-sensitive neurons to generating oscillatory potentials in Royal College of Surgeons rats

Purpose

We investigated how the N-methyl-dl-aspartic acid (NMDA) receptor contributes to generating oscillatory potentials (OPs) of the electroretinogram (ERG) in the Royal College of Surgeons (RCS) rat.

Methods

Scotopic ERGs were recorded from dystrophic and wild-type congenic (WT) RCS rats (n = 20 of each) at 25, 30, 35, and 40 days of age. The stimulus intensity was increased from ?2.82 to 0.71 log cd-s/m² to obtain intensity-response function. NMDA was injected into the vitreous cavity of the right eyes. The left eyes were injected with saline as controls. The P3 obtained by a-wave fitting was digitally subtracted from the scotopic ERG to isolate the P2. For the OPs, the P2 was digitally filtered between 65 and 500 Hz. The amplitudes of OP1, OP2, OP3, and OP4 were then measured and summed and designated as ΣOPs. The implicit times of OP1, OP2, and OP3 were also measured. The frequency spectra of the OPs were analyzed using fast Fourier transform (FFT).

Results

The maximum ERG a- and b-waves as well as ΣOPs amplitudes reduced with age in dystrophic rats. Compared with intravitreal saline injection, administration of NMDA decreased ΣOPs amplitudes from 30 days of age in dystrophic rats, while it did not attenuate ΣOPs amplitudes in WT rats. The implicit times of the OPs of the maximum ERG were prolonged by NMDA injections in WT and dystrophic rats. NMDA/saline ratios of ΣOPs amplitudes area under the FFT curves were significantly lower in dystrophic rats from 30 days of age than that in WT rats.

Conclusion

In the early stage of photoreceptor degeneration, intravitreal NMDA injection attenuated OPs amplitudes in dystrophic rats. This indicates that NMDA receptors play a significant role in generating OPs amplitudes with advancing photoreceptor degeneration.     

Spectral domain optical coherence tomography findings in bilateral peripheral cone dystrophy

Introduction

To report spectral domain optical coherence (OCT) tomography findings in a case of bilateral peripheral cone dystrophy.

Case Report

A 21-year-old man complained of blurred visual fields on the lateral sides of both eyes. The patient’s best-corrected visual acuity was 20/20 in both eyes. Fundus examination revealed mild temporal pallor, while fluorescein angiography did not show any abnormalities. Humphrey’s visual field revealed a C-shaped scotoma. Photopic electroretinogram (ERG) and 30-Hz flicker revealed decreased cone function; however, scotopic ERG noted a normal response. Multifocal ERG revealed a relatively well-preserved macular area but with reduced amplitude in the peripheral areas of both eyes. On OCT, the photoreceptor inner and outer segment junction and retinal pigment epithelium (RPE) layers were well preserved in both eyes, except for a slight decrease in outer layer thickness. Moreover, on the macular thickness map obtained from Cirrus HD-OCT, a reduction in internal limiting membrane-RPE thickness that correlated well with visual field defects was revealed in both eyes. On the retinal nerve fiber layer (RNFL) thickness map obtained from Cirrus HD-OCT, the superior quadrant showed decreased RNFL thickness; however, thickness in the temporal quadrant corresponded with thickness in the macular area and was normal in both eyes.

Discussion

The OCT of a patient with peripheral cone dystrophy revealed decreased thickness of the macula with well-preserved retinal structures, which may be one of the distinctive features of this condition.     

Klinik und Diagnostik der Zapfen-Dystrophien

Background

Cone dystrophies present with highly variable clinical findings and often limited retinal changes, which may lead to misdiagnosis. The purpose of the present review of the clinical presentation and diagnosis of cone dystrophies is to provide guidelines for improved patient care.

Methods

A literature search and evaluation of the clinical findings were carried out in 450 patients with cone dystrophy examined between 1986 and 2008.

Results

Characteristic signs are loss of visual acuity, photophobia and central scotoma. The diagnosis of cone dystrophy is determined by a full-field electroretinogram (ERG). Fundus and near-infrared autofluorescence as well as optical coherence tomography allow detection of retinal structural abnormalities even when findings from ophthalmoscopy are normal.

Conclusion

The diagnosis of cone dystrophy is difficult due to unspecific subjective symptoms and absence of characteristic ophthalmoscopic findings. The differential diagnosis of unexplained visual loss should include cone dystrophy and requires either a full-field or multifocal ERG.     

Possible implications of acid-sensing ion channels in ischemia-induced retinal injury in rats

Background

Retinal ischemia in eyes with diabetic retinopathy and retinal vein occlusion leads to local tissue acidosis. Acid-sensing ion channels (ASICs) are expressed in photoreceptors and other neurons in the retina, and may play a role in acid-induced cell injury. The purpose of this study was to investigate the neuroprotective effects of amiloride, an ASIC blocker, on induced retinal ischemia in rats.

Methods

Transient retinal ischemia was induced in male Long–Evans rats by the temporary ligation of the optic nerve. Just before the induction of ischemia, the experimental eyes underwent intravitreal injection of amiloride. On day 7, the retinal damage in eyes that underwent amiloride treatment (and in those that did not undergo the treatment) was evaluated by histology and electroretinogram (ERG).

Results

Transient retinal ischemia caused retinal degeneration with thinning of the inner layer of the retina. The blockage of ASICs with amiloride significantly prevented retinal degeneration. ERG demonstrated that the reduction in a- and b-wave amplitudes induced by the transient retinal ischemia was significantly prevented by the application of amiloride.

Conclusions

The present study suggests that ASICs might, at least in part, play a pathophysiological role in ischemia-induced neurodegeneration. Blockage of ASICs may have a potential neuroprotective effect in ocular ischemic diseases.     

Contribution of retinal ganglion cells to the mouse electroretinogram

Purpose

To quantify the direct contribution of retinal ganglion cells (RGCs) on individual components of the mouse electroretinogram (ERG).

Methods

Dark- and light-adapted ERGs from mice 8 to 12 weeks after optic nerve transection (ONTx, n = 14) were analyzed through stimulus response curves for a- and b-waves, oscillatory potentials (OPs), positive and negative scotopic threshold response (p/n STR), and the photopic negative response (PhNR) and compared with unoperated and sham-operated controls, as well as to eyes treated with 6-cyano-7-nitroquinoxaline-2,3-dion (CNQX).

Results

We confirmed in mice that CNQX intravitreal injection reduced the scotopic a-wave amplitude at high flash strength, confirming a post-receptoral contribution to the a-wave. We found that ONTx, which is more specific to RGCs, did not affect the a-wave amplitude and implicit time in either photopic or scotopic conditions while the b-wave was reduced. Both the pSTR and nSTR components were reduced in amplitude, with the balance between the two components resulting in a shortening of the nSTR peak implicit time. On the other hand, amplitude of the PhNR was increased while the OPs were minimally affected.

Conclusion

With an intact a-wave demonstrated following ONTx, we find that the most robust indicators of RGC function in the mouse full-field ERG were the STR components.     

Retinal dysfunction in a presymptomatic patient with Huntington’s disease

Purpose

Huntington’s disease (HD) is an autosomal dominant, neurodegenerative disorder characterized by progressive motor dysfunction, cognitive decline, and psychiatric disturbances. Studies have shown retinal abnormalities in patients and mouse models with HD; however, to our knowledge, no prior research papers evaluated retinal structure and function in a presymptomatic patient with HD. The aim of this report is to present a case of retinal dysfunction in a presymptomatic patient with HD.

Methods

We investigated retinal structure and function in a 25-year-old male who tested positive for the gene that causes HD, but did not have any symptoms normally associated with HD. Vision and ocular testing included a comprehensive dilated ophthalmic examination, 24-2 full-threshold Humphrey visual field, spectral-domain optical coherence tomography (SD-OCT), fundus photography, full-field electroretinogram (ERG), and multifocal electroretinogram (mfERG).

Results

Visual electrophysiology testing showed rod and cone functional anomalies in both eyes. Full-field ERG amplitudes were subnormal in both eyes for the dark-adapted (DA) 0.01 ERG, DA 3 ERG, DA 3 oscillatory potentials (OPs), DA 10 ERG, light-adapted (LA) 3 ERG, and LA 30 Hz flicker, but peak times for the six standard ERG responses were not significantly different from normals. mfERGs revealed functional anomalies of the central retina with attenuated P1 amplitudes for five of the six concentric rings in the right eye and all six rings in the left eye. mfERG P1 peak times were normal at all eccentricities. Dilated fundus examination, SD-OCT, and fundus photography were unremarkable in both eyes. The visual field was normal in the right eye, but there was a mild paracentral field defect in the left eye.

Conclusions

Our results illustrate that the ERG and mfERG detected early retinal dysfunction in a presymptomatic patient with HD consistent with electroretinogram findings in animal models of HD. However, our report was limited to one patient and additional studies are needed to verify whether the ERG and/or mfERG can uncover neural dysfunction before motor, behavioral, and cognitive abnormalities are discernible in patients with HD.

     

The 52nd ISCEV International Symposium Abstract Issue

Purpose

We have monitored retinal function in patients treated for retinoblastoma (primarily, but not exclusively by intra-arterial chemotherapy infusion) by electroretinography (ERG) recordings for the past 7 years. We here present data from 599 ERG studies of 108 patients, in which a complete ERG protocol including both photopic and scotopic recordings was performed, in justification of our frequent practice of reporting primarily 30-Hz photopic flicker amplitude data.

Methods

Patients referred for treatment of retinoblastoma underwent ERG recordings during examination under anesthesia whenever possible: at baseline and following most treatment sessions. Correlations were calculated for the complete datasets between the four primary amplitude response parameters: photopic single flash b-wave, photopic 30-Hz flicker peak-to-trough, scotopic rod-isolating b-wave, and scotopic maximal flash b-wave.

Results

Using our adaptation of the International Society for Clinical Electrophysiology of Vision-recommended standard ERG protocol, ERG responses of eyes of patients with untreated retinoblastoma or following traditional or intra-arterial treatment for retinoblastoma show very high correlations between 30-Hz flicker amplitude responses and three other standard photopic and scotopic ERG response amplitudes. Reductions in ERG amplitudes seen in these eyes following treatment show no significant difference between retinal dysfunction estimated using rod- or cone-dominated responses.

Conclusion

These observations support the use of photopic response amplitudes (especially in response to 30-Hz flicker) as the primary ERG outcome measure in studies of treated and untreated eyes with retinoblastoma when more complete ERG protocols may be impractical.     

Full-field electroretinogram response to increment and decrement stimuli

Purpose

The d-wave is typically elicited after the termination of an increment flash, but a decrement flash provides an alternative, and perhaps more appropriate, stimulus to elicit the d-wave. Here, we investigated the affects of stimulus polarity on the electroretinogram (ERG) response.

Methods

ERG responses elicited to increment and decrement flashes of varying intensity and duration from different background levels were measured from human participants to assess the b-wave and d-wave responses as a function of adaptation level and flash polarity. Response amplitudes were measured using standard metrics for waveform analysis.

Results

The amplitude of the b-wave is larger than the d-wave regardless of flash polarity when using different background levels which maximized the dynamic range of the two waveforms. However, when response amplitudes are measured from a common background, the d-wave elicited with decrement flash was larger than the b-wave elicited by an increment flash. This trend was evident across a range of background levels. The b-wave and d-wave become separate entities when flash duration reaches approximately 50 ms. Rapid-on and rapid-off sawtooth stimuli were also tested against increment and decrement step stimuli that were matched in mean luminance. These two stimulus types produced different amplitude b-wave and d-wave responses, suggesting asymmetric effects of the two stimulus types on the retinal response.

Conclusions

We conclude that the response properties of the b-wave and d-wave are influenced by the duration, polarity and waveform of the stimulus, as well as the background from which the stimuli arise.     

Evaluation of light- and dark-adapted ERGs using a mydriasis-free,portable system: clinical classifications and normative data

Purpose

The full-field electroretinogram (ff-ERG) is a widely used clinical tool to evaluate generalized retinal function by recording electrical potentials generated by the cells in the retina in response to flash stimuli and requires mydriasis. The purpose of this study was to determine the intra-visit reliability and diagnostic capability of a handheld, mydriasis-free ERG, RETeval (LKC Technologies, Gaithersburg, MD, USA), in comparison with the standard clinical ff-ERG by measuring responses recommended by the International Society for Clinical Electrophysiology of Vision (ISCEV).

Methods

This prospective, cross-sectional study included 35 patients recruited at the Hospital for Sick Children (median age?=?17, range 11 months–69 years) who had undergone a clinical ff-ERG according to ISCEV standards. For RETeval (n?=?35), pupils were undilated in most (n?=?29) and sensor strip electrodes were placed under the inferior orbital rim. Stimulus settings on RETeval were equivalent to those used in the clinical ERG. Fifty-seven control participants (median age?=?22, range 8–65 years) underwent undilated RETeval ERG to establish standard values for comparison. Patient waveform components with amplitudes?<?5th percentile, or implicit times?>?95th percentile of normal relative to control data were classified as abnormal for the RETeval system.

Results

The RETeval system demonstrated a high degree of within-visit reliability for amplitudes (ICC?=?0.82) and moderate reliability for implicit times (ICC?=?0.53). Cohen’s Kappa analysis revealed a substantial level of agreement between the diagnostic capability of RETeval in comparison with clinical ff-ERG (k?=?0.82), with a sensitivity and specificity of 1.00 and 0.82, respectively. Pearson’s correlations for clinical ERG versus RETeval demonstrated a positive correlation for amplitudes across the rod (r?=?0.65) and cone (r?=?0.74) ERG waveforms. Bland–Altman plots showed no bias between the mean differences across all amplitude and implicit time parameters of the two systems.

Conclusions

The present study demonstrated that RETeval is a reliable tool with reasonable accuracy in comparison with the clinical ERG. The portable nature of RETeval system enables its incorporation at resource-limited centers where the ff-ERG is not readily available. The avoidance of sedation and pupillary dilation are added advantages of RETeval ERG.

     

Electroretinograms and level of aqueous vascular endothelial growth factor in eyes with hemicentral retinal vein occlusion or branch retinal vein occlusion

Purpose

Hemicentral retinal vein occlusion (hCRVO) is a disease related to CRVO but not to branch retinal vein occlusion (BRVO). We reported a significant correlation between aqueous vascular endothelial growth factor (VEGF) levels and the implicit time of 30-Hz flicker electroretinogram (ERG) in CRVO eyes. The purpose of this study was to compare aqueous VEGF levels and ERG components between hCRVO and BRVO eyes.

Methods

The medical records of patients with macular edema secondary to hCRVO (12 eyes) or BRVO (16 eyes) and received an intravitreal injection of bevacizumab (IVB) at the Nagoya University Hospital from July 2009 to May 2013 were reviewed. Full-field ERGs were recorded before the IVB. Aqueous humor was collected just before the IVB to measure VEGF concentration. Differences in aqueous VEGF level and ERG components between hCRVO and BRVO eyes were determined.

Results

Mean aqueous VEGF concentration in hCRVO eyes was significantly higher than that in BRVO eyes (504 vs. 148 pg/ml, P < 0.05). The implicit time of 30-Hz flicker ERG was significantly longer in hCRVO than in BRVO eyes (33.5 vs. 29.8 ms, P < 0.01).

Conclusion

The significant difference in VEGF levels in aqueous and implicit times of 30-Hz flicker ERG suggest that retinal ischemia is more manifest in hCRVO than in BRVO eyes.     

Changes of Oscillatory Potentials and Photopic Negative Response in Patients with Early Diabetic Retinopathy

Purpose

To investigate the clinical significance of the oscillatory potentials (OPs) and photopic negative response (PhNR) of the electroretinogram (ERG) in patients with early diabetic retinopathy.

Methods

One hundred two diabetic patients with diabetic retinopathy at different stages were examined. Thirty-two age-matched normal controls were also studied. Full-field maximal and photopic cone ERGs were recorded. The amplitudes and implicit times of the OPs, cone b wave, and PhNR were compared at the different stages of diabetic retinopathy.

Results

The a and b wave amplitudes of the maximal scotopic ERGs remained unchanged despite advancing stages of retinopathy, but the OP amplitudes were significantly attenuated even at an early stage of diabetic retinopathy. The amplitudes of both the PhNR and cone b wave were reduced at an early stage of diabetic retinopathy. Analysis of the receiver operating characteristic curves demonstrated that the amplitudes and implicit times of the OPs were more sensitive and specific than those of the PhNR in detecting changes of retinal function in the early stages of diabetic retinopathy.

Conclusions

The amplitudes of the OPs and PhNR progressively decrease with the progression of diabetic retinopathy. The PhNR amplitudes were reduced along with the cone b wave, indicating that earlier change of the PhNR in diabetic patients reflects reduced input to the retinal ganglion cell from the distal retina. The amplitudes and implicit times of the OPs are better indicators than those of the PhNR in detecting functional decreases in patients with early diabetic retinopathy.?Jpn J Ophthalmol 2006;50:367–373 © Japanese Ophthalmological Society 2006     

Functional and high resolution retinal imaging assessment in a case of ocular siderosis

Purpose

To report new findings in a case of ocular siderosis explored by high resolution angiography and adaptive optics (AO).

Methods

We report data on a 40-year-old man with an intraocular foreign body (IOFB) embedded in the sclera after hammering.

Results

Nine months after this accident, the patient presented with full-field electroretinogram (FF-ERG) abnormalities. Subsequent IOFB extraction was performed. One month after the surgery, high resolution angiography showed for the first time small iron particles all over the inner retinal surface. Spreading of these deposits was followed by inflammatory prepapillary new vessels and venous retinal vasculatis, which spontaneously resolved within a few months. ERG responses became slightly electronegative at this time. Clearance of the iron particles was followed over a year with AO and ERG recording. AO revealed an arterial tropism with a decrease in the amount of particles overtime, which may be consistent with macrophagic activity.

Conclusion

High resolution angiography and AO are new tools, combined with electrophysiology, to better understand ocular siderosis pathophysiology.     

Corneal biomechanical properties in eyes with no previous surgery, with previous penetrating keratoplasty and with deep anterior lamellar keratoplasty

Purpose

To compare the biomechanical properties of the cornea in eyes with no previous surgery, with keratoconus with previous penetrating keratoplasty (PK) and with keratoconus with previous deep anterior lamellar keratoplasty (DALK) using the Reichert Ocular Response Analyzer (ORA).

Methods

One hundred twenty eyes of 120 patients were included in this prospective comparative study. Forty eyes were with no previous ocular surgery (group 1), 40 eyes were with previous PK for keratoconus (group 2), and 40 eyes were with previous DALK for keratoconus (group 3). Corneal hysteresis (CH) and the corneal resistance factor (CRF) were measured with ORA.

Results

The CH and CRF values in group 2 were significantly lower than in group 1 and group 3 (p = 0.001). The CH and CRF values were similar in group 1 and group 3. There was no statistically significant difference between group 1 and 3.

Conclusion

Although the post-PK keratoconus cornea has weaker biomechanical properties, post-DALK keratoconus cornea is similar to normal cornea. A cornea weakened by keratoconus can be strengthened with lamellar keratoplasty.     

Retinal function and PKC alpha expression after focal laser photocoagulation

Purpose

To examine the effects of focal laser photocoagulation on general and local retinal function and to relate electrophysiological findings with changes in protein kinase C (PKC) alpha expression.

Methods

Twelve rabbits were treated with 70 spots of laser photocoagulation in the central cone-rich retina. The operated eyes were investigated with electroretinography (full-field ERG and multifocal electroretinography, mfERG) preoperatively and at 1, 3, and 5 weeks after surgery. The expression of PKC alpha was examined at all three time points using immunohistochemistry, and PKC alpha mRNA levels were quantified using real-time polymerase chain reaction (PCR). Immunohistochemistry for glial fibrillary acidic protein (GFAP) and hematoxylin and eosin staining was employed to monitor the extent and dynamics of the morphological response.

Results

The full-field ERG revealed a significant increase in b-wave amplitudes derived from the isolated rod response (blue light) at all three time points after surgery (p?Conclusions Focal laser treatment in the rabbit eye induces local and wide-spread alterations in both rod- and cone-mediated retinal function in the form of supernormal b-wave amplitudes in the full-field ERG and increased latency in the mfERG. The electrophysiological abnormalities are accompanied by a progressive down-regulation of the PKC alpha isoenzyme in rod bipolar cells, reaching far beyond the treated area. PKC alpha is down-regulated directly by impaired protein synthesis, and also possibly indirectly by protein consumption related to GFAP up-regulation. The results indicate that focal laser photocoagulation interferes with PKC-alpha-mediated inhibitory regulation of inner retinal signal transmission.     

Bestimmung viskoelastischer Hornhauteigenschaften (korneale Hysterese) bei Patienten mit primärem Offenwinkelglaukom

Background

The ocular response analyzer (ORA) uses an air-pressure-triggered, dynamic, bi-directional corneal applanation method to measure biomechanical parameters of the cornea. Corneal hysteresis (CH) is defined as the difference in intraocular pressure recorded during inward and outward applanation. CH is therefore an indicator for the viscoelastic properties of the cornea.

Patients and methods

CH was recorded in non-glaucoma patients (80 eyes) as well as in patients with primary open angle glaucoma (POAG, 82 eyes). The correlation between CH and central corneal thickness (CCT) was analyzed.

Results

Mean CH was 10.6±2.2 mmHg in the non-glaucoma group and 9.3±2.2 mmHg in patients with POAG (p<0.01). CH and CCT showed a positive correlation in non-POAG patients, however no such correlation was found in the POAG group.

Conclusion

Patients with POAG show an alteration of biomechanical corneal parameters with a significant decrease in corneal hysteresis. A positive correlation between CH and CCT, which was seen in the non-glaucoma group could not be detected in the POAG group.     

Evaluating retinal toxicity of a new heavy intraocular dye, using a model of perfused and isolated retinal cultures of bovine and human origin

Background

Dyes such as brilliant blue (BBG) are used during vitreoretinal surgery to visualize anatomical structures. By adding deuterium oxide (D2O), surgeons have tried to create a dye mixture heavier than water to facilitate staining of the inner limiting membrane (ILM) without prior fluid–air exchange. This study investigated the effect of 0.4?ml BBG (Fluoron, Ulm, Germany) mixed with 0.13?ml/ml D2O and D2O on retinal function of a pseudo in vivo model using bovine and human whole mount cultures.

Methods

Bovine and human retinas were superfused, and the electroretinogram (ERG) was recorded. BBG with 0.13?ml/ml D2O and D2O were applied epiretinally, different staining periods (10, 30, 60 and 120?s) were tested, and ERG recovery was monitored. 1?mM aspartate was added to the nutrient solution to examine the photoreceptor reaction.

Results

Reductions of the a- and b-wave amplitudes were found directly after exposure with BBG with 0.13?ml/ml D2O and with D2O in all test series. These effects on the electroretinogram were rapidly and completely reversible within the recovery time for all exposure times. ERG amplitudes measured after dye application at the end of the washout did not differ significantly from those recorded before staining.

Conclusions

The clinically used mixture of BBG/D2O seems to be safe for clinical use. Staining periods of more than 120?seconds were not tested.     

Comparison of corneal sensitivity between FS-LASIK and femtosecond lenticule extraction (ReLEx flex) or small-incision lenticule extraction (ReLEx smile) for myopic eyes

Background

To compare the effect on corneal sensitivity between femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and femtosecond lenticule extraction (ReLEx flex) or FS-LASIK and small-incision lenticule extraction (ReLEx smile) surgery.

Methods

Twenty-seven subjects (54 eyes) underwent FS-LASIK, 22 subjects (40 eyes) underwent ReLEx flex, and 32 subjects (61 eyes) underwent ReLEx smile surgery. Cochet-Bonnet esthesiometry (Luneau Ophthalmologie Chartres, Cedex, France) was used to evaluate corneal sensitivity preoperatively as well as at 1 week and 1 and 3 months after surgery.

Results

At 1 week, central, superior, nasal, and temporal corneal sensitivity in the ReLEx flex group was significantly higher than in the FS-LASIK group (P?=?0.007, 0.004, 0.020, 0.004 respectively) and in the central and inferior areas at 3 months (P?=?0.002, 0.009 respectively). A higher corneal sensitivity after ReLEx smile surgery was observed in every quadrant at 1 week and 1 and 3 months compared with FS-LASIK surgery (P?<?0.01). Furthermore, in the ReLEx smile group, there were no statistical differences in the superior and temporal quadrants at 1 month postoperatively compared with preoperatively (5.19?±?0.61 cm, P?=?0.198 and 5.64?±?0.48 cm, P?=?0.330 respectively) and no significant differences in any quadrant at 3 months.

Conclusions

Postoperative corneal sensitivity was not remarkably changed after ReLEx smile surgery compared with FS-LASIK. This might be because ReLEx is a flapless procedure.     

Pattern electroretinogram in neuromyelitis optica and multiple sclerosis with or without optic neuritis and its correlation with FD-OCT and perimetry

Purpose

To evaluate the ability of transient pattern electroretinogram (PERG) parameters to differentiate between eyes of patients with neuromyelitis optica (NMO), longitudinally extensive transverse myelitis (LETM), multiple sclerosis with optic neuritis (MS + ON), multiple sclerosis without optic neuritis (MS ? ON), and controls, to compare PERG and OCT with regard to discrimination ability, and to assess the correlation between PERG, FD-OCT, and visual field measurements (VFs).

Methods

Visual field measurements and full-field stimulation PERGs based on both 48- and 14-min checks were obtained from patients with MS (n = 28), NMO (n = 20), LETM (n = 18), and controls (n = 26). In addition, FD-OCT peripapillary retinal nerve fiber layer (RNFL) and segmented macular layer measurements were obtained and their correlation coefficients were determined.

Results

Compared to controls, PERG amplitude measurements were significantly reduced in eyes with NMO and MS + ON, but not in eyes with LETM and MS ? ON. PERG amplitudes were significantly smaller in NMO and MS + ON eyes than in MS ? ON eyes. PERG and OCT performance was similar except in NMO eyes where macular thickness parameters were more efficient at detecting abnormalities. A significant correlation was found between N95 amplitude values and OCT-measured macular ganglion cell layer thickness, total retinal thickness, and temporal peripapillary RNFL thickness. PERG amplitude was also significantly associated with VF sensitivity loss. No statistically significant difference was observed with regard to the best-performing parameters of the two methods.

Conclusions

Pattern electroretinogram measurements were able to detect RNFL loss in MS + ON and NMO eyes, with a performance comparable to OCT. PERG amplitude measurements were reasonably well correlated with OCT-measured parameters.