Retinal function in diabetic macular edema after focal laser photocoagulation

PURPOSE: To assess the effects of focal photocoagulation on retinal function in the macular and perimacular areas in patients with diabetes who have clinically significant macular edema. METHODS: Eleven patients were assessed after focal laser treatment. Multifocal electroretinogram (ERG) and full-field ERG techniques were used to evaluate the effects of treatment on macular, paramacular, and peripheral retinal function. A modified visual field technique was used to obtain local threshold fields. The posttreatment results were compared with pretreatment results. Changes in local ERG response amplitudes and implicit times were calculated for each patient and presented as difference fields. The changes in local ERG responses were compared with the changes in local field sensitivity. RESULTS: After treatment, the results of the psychophysical tests suggested little or no change in visual function, but changes in retinal function were observed with the multifocal ERG technique. Local ERG responses showed increases in implicit time and decreases in amplitude, compared with pretreatment values. Timing was affected more than amplitude. CONCLUSIONS: The results suggest that focal treatment produces changes in retinal function, and these changes are not restricted to the treated macular area.     

Perifoveal function in patients with North Carolina macular dystrophy: the importance of accounting for fixation locus

PURPOSE: To quantify the extent of visual function losses in patients with North Carolina Macular Dystrophy (NCMD) and to demonstrate the importance of accounting for eccentric fixation when making comparisons with normal data. METHODS: Five patients with NCMD who were from a single family were examined. Multifocal electroretinograms (mfERGs) and psychophysical assessments of acuity and luminance visual field sensitivities were measured throughout the central retina. Comparisons of responses from equivalent retinal areas were accomplished by shifting normal templates to be centered at the locus of fixation for each patient. RESULTS: Losses of psychophysically measured visual function in patients with NCMD extend to areas adjacent to the locations of visible lesions. The multifocal ERG amplitude was reduced only within the area of visible lesion. Multifocal ERG implicit times were delayed throughout the entire central retinal area assessed. CONCLUSIONS: ERG timing is a sensitive assay of retinal function, and our results indicate that NCMD has a widespread effect at the level of the mid and outer retina. The findings also demonstrated that it is necessary to account for fixation locus and to ensure that equivalent retinal areas are compared when testing patients with macular disease who have eccentric fixation.     

Photopic temporal processing in retinitis pigmentosa.

PURPOSE: The relation between early changes in the photopic flicker electroretinogram (ERG) and photopic psychophysical changes in retinitis pigmentosa (RP) is poorly understood. Here, abnormalities in foveal and extrafoveal temporal contrast sensitivity functions (TCSFs) were studied in a group of carefully selected patients with RP who had relatively preserved macular function. The psychophysical results were compared with changes in the timing of the multifocal ERG. METHODS: Subjects were patients with RP who had acuity > or =20/32 and no visual field defects within 6 degrees from the fovea. Maxwellian-view and direct-view optical systems were used to obtain foveal and extrafoveal TCSFs under a range of test conditions, including high retinal illuminances that yielded temporal contrast sensitivity independent of mean retinal illuminance. TCSFs were described using log sensitivity and corner frequency parameters. RESULTS: Foveal TCSFs in these patients showed overall reductions in sensitivity but no frequency-dependent defects. Also, no macular defects were found in the timing of the multifocal ERG. TCSFs from extrafoveal locations in moderate field defects, obtained at retinal illuminances that were sufficient to render flicker sensitivity independent of effective mean luminance, showed reductions in overall sensitivity as well as changes in temporal tuning. The multifocal ERGs from these extrafoveal locations showed signs of temporal slowing. CONCLUSIONS: Changes in temporal tuning (both psychophysical and electroretinographic) were found only within visual field scotomas, whereas changes of the log sensitivity parameter were found also in the relatively preserved foveas of this group of patients with early stage RP.     

Diabetic macular edema: correlation between microperimetry and optical coherence tomography findings

PURPOSE: To compare the changes in macular sensitivity (microperimetry) and macular thickness with different degrees of diabetic macular edema. METHODS: Sixty-one eyes of 32 consecutive diabetic patients were included in this cross-sectional study. All included eyes underwent functional and morphologic examination of the macular area. Best corrected visual acuity (ETDRS charts), macular sensitivity, and macular thickness were quantified. Lesion-related macular sensitivity and retinal fixation were investigated with an advanced, automatic microperimeter. Optical coherence tomography (OCT) was used to quantify macular thickness. RESULTS: The 61 included eyes were graded, by two retinal specialists, for diabetic macular edema as follows: 16 were graded as no macular edema (NE), 30 as non-clinically significant macular edema (NCSME), and 15 as clinically significant macular edema (CSME). Macular thickness significantly increased from the NE to the CSME group (P<0.0001), whereas macular sensitivity significantly decreased from the NE to the CSME group (P<0.0021). A significant correlation coefficient was noted between retinal sensitivity and normalized macular thickness (r=-0.37, P<0.0001). Linear regression analysis showed a decrease of 0.83 dB (P<0.0001) for every 10% of deviation of retinal thickness from normal values. Visual acuity and central macular sensitivity correlated significantly in the NCSME group (r=-0.6, P=0.0008), but not in the NE (r=-0.144, P=0.6) or in the CSME (r=-0.46, P=0.11) groups. CONCLUSIONS: Macular edema may be better documented by adding macular sensitivity mapping by microperimetry to macular thickness measurement by OCT and visual acuity determination because macular sensitivity seems to be a relevant explanatory variable of visual function, independent of macular thickness data. Moreover, microperimetry may be of value in predicting the outcome of diabetic macular edema, because it incorporates a functional measure that may supplement the predictive value of OCT and visual acuity.     

Binocular fixation topography in patients with diabetic macular oedema

BACKGROUND: During retinal photocoagulation for diabetic maculopathy, there is a potential risk of foveal burns, and laser scars may later enlarge to be sight-threatening when involving retinal areas previously used during fixation. Since the retinal area used during binocular steady fixation has been found to vary considerably in the normal test person and central fixation may be even further compromised in patients with diabetic maculopathy, the sight-threatening side effects could possibly be reduced by taking into account the fixation area individually. However, no study has described and quantified the retinal area of fixation binocularly in patients with clinically significant macular oedema (CSME). METHODS: Sixteen diabetic patients with CSME in one or both eyes were examined. Each examination included visual acuity testing (ETDRS charts), a standard eye examination, central retinal thickness assessment by optical coherent tomography, fluorescein angiography and binocular quantification of fixational eye movements using an infrared recording technique. RESULTS: A negative correlation was found between visual acuity and mean microsaccadic amplitude (R=0.48, p=0.009). The maximal retinal extension of the fixation area ranged between 1.0 degrees and 3.0 degrees , and in two eyes with CSME, this area was estimated to exceed 800 mum on the retinal plane. No correlation was found between retinal thickness and visual acuity, retinal area of fixation, maximal extension of the fixation area or mean microsaccadic amplitude. CONCLUSION: Large interindividual differences in quantitative measures of binocular fixational eye movements were found. The mean amplitude of fixational eye movements was not correlated to central retinal thickness, and fixation area could only partly be predicted by visual acuity. Two eyes with CSME had an estimated maximal extension of the fixation area exceeding the central 800 mum on the retinal plane; thus, the possible benefit of individualising central photocoagulation according to precise measures of fixation area needs to be investigated on a larger population.     

Comprehensive functional vision assessment of patients with North Carolina macular dystrophy (MCDR1)

PURPOSE: Previous studies indicated abnormal development of fixation toward the optic nerve head in patients with the inherited retinal disease North Carolina macular dystrophy (NCMD). The implication of this development on functional vision and structural characteristics has not been described. METHODS: The anatomical characteristics of five NCMD-affected individuals were assessed by measuring the retinal thickness of the macula using optical coherence tomography. The underlying physiologic health of the retina was assessed using the multifocal ERG. Psychophysical assessment of remaining vision in the affected areas was done with a new microperimetry system that measures functional visual acuity at 27 discrete locations and the Humphrey visual field analyzer. RESULTS: All patients had better areas of visual sensitivity toward the nasal macula. Follow-up examination showed no changes in the clinical appearance of the retina. Visual acuities ranged from -0.10 logMAR (Snellen equivalent, approximately 20/16) to 0.50 logMAR (Snellen equivalent, approximately 20/63) in the better eye. No significant changes in visual acuity were found over time. Local multifocal electroretinogram deficits were found in all patients. Patients with grade 2 or 3 disease had large patches of decreased amplitudes and delayed implicit times. Results of the anatomical, electrophysiological, and psychophysical tests were consistent. CONCLUSION: The electrophysiological and psychophysical deficits found in patients with more severe disease were consistent with an abnormal development of fixation from the anatomical fovea toward the optic nerve head with the placement of the lesion temporal to fixation (into the nasal visual field).     

Retinal thickness study with optical coherence tomography in patients with diabetes

PURPOSE: To quantitatively assess retinal thickness by optical coherence tomography (OCT) in normal subjects and patients with diabetes. This study was intended to determine which retinal thickness value measured with OCT best discriminates between diabetic eyes, with and without macular edema. METHODS: OCT retinal thickness was measured by a manual technique in a total of 26 healthy volunteers (44 control eyes) and 85 patients with diabetes (148 eyes) with the clinical diagnosis of no diabetic retinopathy (45 eyes), nonproliferative diabetic retinopathy without clinically significant macular edema (CSME; 54 eyes), proliferative diabetic retinopathy without CSME (21 eyes), and 28 eyes with diabetic retinopathy with CSME. Independent predictors of the presence of CSME were quantified by using univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curves were generated to evaluate and compare the predictor variables. The correlation of retinal thickness measurements and visual acuity was calculated. RESULTS: There were statistically significant differences in foveal thickness between control eyes and all the other eye groups (P = 0.001). Diabetic eyes with CSME had a statistically significant greater thickness in each of the areas compared with the other groups. In a multivariate logistic regression model, foveal thickness was a strong and independent predictor of CSME (odds ratio [OR], 1.037; 95% confidence interval [CI] 1.02-1.05). The area under the ROC curve of this predictor variable was 0.94 (P = 0.001). For a cutoff point of 180 microm, the sensitivity was 93%, and specificity was 75%. Foveal thickness correlated with visual acuity in a log minimum angle of resolution (logMAR) scale (Spearman's rho = 0.9, P = 0.001). CONCLUSIONS: These results suggest that foveal thickening over 180 microm measured by OCT may be useful for the early detection of macular thickening and may be an indicator for a closer follow-up of the patient with diabetes.     

Multifocal electroretinogram in occult macular dystrophy

PURPOSE: Occult macular dystrophy (OMD) is an unusual macular dystrophy presenting with an essentially normal fundus and fluorescein angiography but with progressive central visual loss. The authors studied the function of local retinal areas in the posterior pole of patients with OMD using multifocal electroretinograms (ERGs). METHODS: Multifocal ERGs were recorded using the Visual Evoked Response Imaging System with 61 hexagonal elements within a visual field of 30 degrees radius from 8 OMD patients and 20 age-matched, normal subjects. The amplitudes and implicit times of the patients and normal control subjects were compared at the various retinal eccentricities. RESULTs. The amplitudes of the multifocal ERGs in the OMD patients were markedly reduced in the central 7 degrees of the fovea. The difference of the ERG amplitudes between OMD and normal subjects became smaller toward the peripheral retina. Most OMD patients had slight but significantly delayed implicit times across the whole testing field, and the differences between the OMD and the normal subjects did not change with retinal eccentricity. CONCLUSIONS. Our results for multifocal ERG amplitudes support the idea that OMD patients have localized retinal dysfunction distal to the ganglion cells in the central retina. The delayed implicit times across the whole test field suggest that the retinal dysfunction has a broader boundary than expected by ERG amplitudes and psychophysical perimetric results.     

Evaluation of typical and atypical retinal pigmentary dystrophy by three dimensional analysis (XY plane and time) of averaged electroretinograms

Retinal functional imaging of patients with typical and atypical retinal pigmentary dystrophies was investigated by three dimensional (XY plane and time) analysis of ERG topography by comparing visual field and fluorescein angiographic findings. The three dimensional analysis revealed that the area of maximal amplitude deviated to the skin area closest to the dominant location of the retinal pigmentary dystrophy (the so-called paradoxical localization). In patients with temporoinferior sectorial retinal pigmentary dystrophy, for example, the maximal amplitude of the a-, b-waves and retinal oscillatory potentials deviated toward the temporoinferior side on the surface topography. These characteristic phenomena of a- and b-waves were found in 60.8% of all patients. Flicker topography with a stimulus frequency of 30 Hz was especially successful in showing the existence and location of paramacular involvement of retinal dystrophy within the area surrounding temporal vascular arcades. The detectability of macular asymmetric involvement was 65.2%. No significant topographic changes were detected in cases in the early stage with no remarkable visual field defects, or in the end stage with remarkable concentric field defects and complicated glaucomatous visual field defects. A comparative study of topographic changes, visual field changes and fluorescein angiographic findings showed that topographic changes in the a-, b-waves, retinal oscillatory potentials and 30Hz flicker components coincided more closely with visual field changes than fluorescein angiographic findings. We proposed that retinal pigmentary dystrophy is not a homogeneous lesion in its progression and believe that the ERG topography method can, by the imaging of dominant locations, detect this disease as well as visual field testing.     

Ethambutol neuroretinopathy

OBJECTIVE: To describe the clinical features of ethambutol neuroretinopathy. DESIGN: Case report and meta-analysis of the literature. PARTICIPANTS: A patient with clinical and electrophysiological findings suggestive of ethambutol neuroretinopathy. TESTING: Electroretinogram, electro-oculogram and visual fields. MAIN OUTCOME MEASURE: Clinical and electrophysiological findings. RESULTS: 101 cases were reviewed, retinal findings include retinal pigment epithelial changes, macular edema, flame-shaped hemorrhages. Electroretinogram findings include decreased amplitude and abnormal wave pattern in full field ERG, multifocal or pattern ERG and electro-oculogram findings include abnormal Arden ratio. CONCLUSIONS: Clinical, electrophysiological and in vitro studies support the toxic effect of ethambutol on the retina. Therefore ethambutol ocular toxicity may be a neuroretinopathy.     

Quantitative assessment of retinal thickness in diabetic patients with and without clinically significant macular edema using optical coherence tomography

PURPOSE: To assess patients with diabetic macular edema quantitatively using optical coherence tomography (OCT). METHODS: OCT was performed in 14 eyes with diabetic retinopathy and ophthalmoscopic evidence of clinically significant macular edema (CSME) and in 19 diabetic eyes without CSME. Retinal thickness was computed from the tomograms at fovea and other 36 locations throughout the macula. RESULTS: The mean +/- standard deviation foveal thickness was 255.6 +/- 138.9 microm in eyes with CSME, and 174.6 +/- 38.2 microm in eyes without CSME (p = 0.051). Within 2000 microm of the center of the macula, eyes with CSME had significantly thicker retina in the inferior quadrant than those without CSME (p < 0.01). The foveal thickness was correlated with logMAR visual acuity (gamma = 0.68, p < 0.01). OCT identified sponge-like retinal swelling and/or cystoid macular edema in 11 (58%) eyes without CSME, and in 12 (86%) eyes with CSME. CONCLUSIONS: Criteria of CSME seem to be insufficient in really identifying macular edema. OCT may be more sensitive than a clinical examination in assessing diabetic macular edema and is a quantitative tool for documenting changes in macular thickening.     

Symptomatic abnormalities of dark adaptation in patients with EFEMP1 retinal dystrophy (Malattia Leventinese/Doyne honeycomb retinal dystrophy)

PURPOSE: To investigate the nature of symptomatic visual disturbance in patients with EFEMP1 retinal dystrophy in the absence of geographic atrophy or choroidal neovascularization. METHODS: Patients presenting to a tertiary referral centre underwent clinical evaluation, fluorescein angiography, colour contrast sensitivity, focal, pattern, and standard electroretinography, electrooculography, scotopic threshold perimetry and dark adaptometry. RESULTS: Clinical features included reduced central vision, difficulty passing from light to dark, and diffuse submacular and peripapillary deposits, which were hyperfluorescent by fluorescein angiography. Colour contrast thresholds were abnormal in all six patients studied and both pattern and focal electroretinograms were abnormal in five of six patients. The scotopic and mixed rod-cone single flash ERG was normal but two patients demonstrated reduced oscillatory potentials and one had borderline delayed 30 Hz responses. Scotopic thresholds were elevated and rod-mediated dark adaptation kinetics were markedly prolonged in all six patients when measured over the central visible confluent deposits. CONCLUSIONS: In patients with EFEMP1 retinal dystrophy with confluent macular deposits, scotopic sensitivity is reduced and dark adaptation kinetics are prolonged over the macular deposits but are normal elsewhere. These results emphasize the localised nature of functional deficits in some patients with EFEMP1 retinal dystrophy and correlate well with the patient's visual symptoms. Symptomatic visual dysfunction may precede the development of clinically evident geographic atrophy or choroidal neovascularization in this disorder.     

A Korean family with an early-onset autosomal dominant macular dystrophy resembling North Carolina macular dystrophy

PURPOSE: To characterize and report the phenotype of a Korean family with an early-onset autosomal dominant macular dystrophy resembling North Carolina macular dystrophy (NCMD). METHODS: Five members of a Korean family were examined clinically and underwent fundus photography, fluorescein angiography, indocyanine green angiography, optical coherence tomography, full field electroretinogram (ERG), multifocal ERG, electro-oculography (EOG), a color vision test, and a visual field test. RESULTS: Visual acuity ranged from 20/200 to 20/20. Fundus findings demonstrated varying degrees of involvement ranging from drusen only to chorioretinal involvement. Central scotoma corresponded to retinal lesions in two patients. Full field ERG was normal but multifocal ERG showed decreased amplitude and delayed implicit time in the macular area. EOG was normal except in one patient. Color vision tests were also normal. CONCLUSIONS: The phenotype of this Korean family is consistent with NCMD. Linkage analysis is required to confirm the diagnosis.     

Acute macular neuroretinopathy--case report

PURPOSE: The aim of this study is to present rare retinal disease of unknown origin. MATERIAL AND METHODS: 27-years-old man was diagnosed because of poor vision in the left eye, which lasted 4-5 weeks. Following examinations were performed: Visual acuity, contrast sensitivity, color perception, visual field, fluorescein angiography (AF), visual evoked potentials (VEP), full-field flash electroretinography (flash ERG), focal-foveal electroretinography (focal ERG), multifocal electroretinography (multifocal ERG). Follow-up 1.5 year. RESULTS: Visual acuity of right eye was 1.25 (-0.1 log MAR) and left eye 1.0 (0.0 log MAR). In left eye between optic disc and macula irregular lesion with dots of retinal pigment epithelium atrophy and little edema was seen. AF revealed small "window" defects. In visual field of the left eye paracentral relative scotoma occurred and in stereokampimetry central relative scotoma was found about 5 degrees from the fixation point. In VEP latency of P100 was delayed and amplitude was reduced in both eyes. In flash as well as focal ERG small reduction of cone function and delayed implicit time of b-wave were found in left eye. In general examination no focal inflammation and no abnormalities in laboratory tests were found. The patient was treated with steroids for 3 weeks. After ten days of general steroid treatment visual acuity improved to 1.25 and subjective improvement of vision occurred. Control examination after 1.5 year revealed no patient's complains, visual acuity 1.25, no change in visual field, VEP improvement. In left eye flat irregular area with pigment epithelium atrophy was seen. CONCLUSIONS: Acute macular neuroretinopathy may be diagnosed after detail examination. Prognosis is generally good, recovery is slow, but despite of local retinal atrophy subjective complains disappear completely.     

Detection using the multifocal electroretinogram of mosaic retinal dysfunction in carriers of X-linked retinitis pigmentosa

PURPOSE: To examine whether a mosaic pattern of retinal dysfunction in obligate carriers of X-linked retinitis pigmentosa (XLRP) could be observed in local electroretinographic responses obtained with the multifocal electroretinogram (mfERG). DESIGN: Prospective observational case series. PARTICIPANTS: Five obligate carriers of XLRP (mean age, 53.2 years) were recruited into the study. METHODS: Examination of each subject included a complete ocular examination, Humphrey visual field, standard full-field electroretinogram (ERG), and mfERG testing. For the mfERG, we used a 103-scaled hexagonal stimulus array that subtended a retinal area of approximately 40 in diameter. The amplitudes and implicit times in each location for the mfERG was compared with the corresponding value determined for a group of normally sighted, age-corrected control subjects. MAIN OUTCOME MEASURES: Mapping of 103 local electroretinographic response amplitudes and implicit times within the central 40 with the multifocal electroretinogram. RESULTS: Localized regions of reduced mfERG amplitudes and/or delayed implicit times were found in four of five carriers. In one of these four carriers, a mosaic pattern of mfERG dysfunction was present even in the absence of any clinically apparent retinal changes, retinal sensitivity losses on Humphrey field testing, or abnormal full-field cone ERG responses. However, one carrier with a typical tapetal-like reflex demonstrated no deficit on any functional tests. CONCLUSIONS: The mfERG demonstrated patchy areas of retinal dysfunction in some carriers of XLRP. This mosaic pattern of dysfunction may be observed in some patients with a normal-appearing fundus, normal psychophysical thresholds, and normal amplitude and implicit time full-field ERG cone responses.     

RDH12-associated retinal degeneration caused by a homozygous pathogenic variant of 146C>T and literature review

AIM: To describe the clinical, electrophysiological, and genetic features of an unusual case with an RDH12 homozygous pathogenic variant and reviewed the characteristics of the patients reported with the same variant. METHODS: The patient underwent a complete ophthalmologic examination including best-corrected visual acuity, anterior segment and dilated fundus, visual field, spectral-domain optical coherence tomography (OCT) and electroretinogram (ERG). The retinal disease panel genes were sequenced through chip capture high-throughput sequencing and Sanger sequencing was used to confirm the result. Then we reviewed the characteristics of the patients reported with the same variant. RESULTS: A 30-year male presented with severe early retinal degeneration who complained night blindness, decreased visual acuity, vitreous floaters and amaurosis fugax. The best corrected vision was 0.04 OD and 0.12 OS, respectively. The fundus photo and OCT showed bilateral macular atrophy but larger areas of macular atrophy in the left eye. Autofluorescence shows bilateral symmetrical hypo-autofluorescence. ERG revealed that the amplitudes of a- and b-wave were severely decreased. Multifocal ERG showed decreased amplitudes in the local macular area. A homozygous missense variant c.146C>T (chr14:68191267) was found. The clinical characteristics of a total of 13 patients reported with the same pathologic variant varied. CONCLUSION: An unusual patient with a homozygous pathogenic variant in the c.146C>T of RDH12 which causes late-onset and asymmetric retinal degeneration are reported. The clinical manifestations of the patient with multimodal retinal imaging and functional examinations have enriched our understanding of this disease.     

The effects of retinal abnormalities on the multifocal visual evoked potential

PURPOSE: To examine the effects on the amplitude and latency of the multifocal visual evoked potential (mfVEP) in retinal diseases associated with depressed multifocal electroretinograms (mfERG). METHODS: Static automated perimetry (SAP), mfERGs, and mfVEPs were obtained from 15 individuals seen by neuro-ophthalmologists and diagnosed with retinal disease based on funduscopic examination, visual field, and mfERG. Optic neuropathy was ruled out in all cases. Diagnoses included autoimmune retinopathy (n = 3), branch retinal arterial occlusion (n = 3), branch retinal vein occlusion (n = 1), vitamin A deficiency (n = 1), digoxin/age-related macular degeneration (n = 1), multiple evanescent white dot syndrome (n = 1), and nonspecific retinal disease (n = 5). Patients were selected from a larger group based on abnormal mfERG amplitudes covering a diameter of 20 degrees or greater. RESULTS: Fourteen (93%) of 15 patients showed significant mfVEP delays, as determined by either mean latency or the probability of a cluster of delayed local responses. Thirteen of 15 patients had normal mfVEP amplitudes in regions corresponding to markedly reduced or nonrecordable mfERG responses. These findings can be mimicked in normal individuals by viewing the display through a neutral-density filter. CONCLUSIONS: Retinal diseases can result in mfVEPs of relatively normal amplitudes, often with delays, in regions showing decreased mfERG responses and visual field sensitivity loss. Consequently, a retinal problem can be missed, or dismissed as functional, if a diagnosis is based on an mfVEP of normal or near-normal amplitude. Further, in patients with marked mfVEP delays, a retinal problem could be confused with optic neuritis, especially in a patient with a normal appearing fundus.     

高度近视眼视功能状态与屈光度相关性的临床研究

目的:观察不同近视屈光度下,高度近视眼视功能状态的改变,寻找不同近视屈光度对高度近视眼功能、形态损害的相关早期客观敏感指征。方法:采用视野的中心低视力程序(LVC)和黄斑程序(M2,C08,TG2),以及视觉电生理系统中反映眼视功能状态的指标进行定性定量观察,包括单次视锥-视网膜电图(ERG)、30Hz闪烁ERG、P-VEP,多焦视网膜电图中一阶反应1、2环。结果:随近视屈光度的增加,视野的光敏感度(MS)下降;视觉电生理中PVEP、单次视锥细胞和30Hz闪烁b波、1环和2环振幅密度、1环b波振幅和2环a、b波振幅和潜时延长有下降(P<0.05);多元逐步回归分析提示,近视屈光度的数值与眼轴呈负相关关系,并与PVEP振幅呈正相关关系、与单次视锥b波潜时呈负相关关系。结论:视野、视觉电生理振幅可以较早检测到不同近视屈光度对视网膜功能的影响。     

Diurnal variation in clinically significant diabetic macular edema measured by the Stratus OCT

PURPOSE: To investigate diurnal variation in clinically significant macular edema (CSME) using the Stratus OCT (Carl Zeiss Meditec). METHODS: Fifteen eyes of 15 diabetic patients with CSME and 10 healthy subjects (controls) underwent four optical coherence tomography (OCT) measurements of macular thickness with the fast macular thickness mapping protocol of the Stratus OCT at 9 am, 12 pm, 3 pm, and 6 pm. Early Treatment Diabetic Retinopathy Study visual acuity and refraction data were also collected at each time. Retinal thickness measurements from each of the nine macular Early Treatment Diabetic Retinopathy Study areas of the retina map, visual acuity, and refraction were plotted over time. RESULTS: Mean retinal thickness remained unchanged in all retinal sectors over the course of the day for the controls and the 6 diabetic patients with a baseline foveal thickness of <300 mum, and it significantly decreased in 7 of the 9 retinal sectors for the 9 diabetic patients with a baseline foveal thickness of > or =300 microm (ANOVA model for repeated measures). In these patients, the mean initial foveal thickening +/- SD of 211 +/- 104 microm was reduced by an average of 6.1%, 15.2%, and 21.2% at 12 pm, 3 pm, and 6 pm, respectively. Two of these nine patients also had an increase in visual acuity without change in refraction. There were no changes in refractive errors over the course of the study in the two groups. A positive correlation between initial central thickening and decrease in thickness was found (r = 0.732; P = 0.002). CONCLUSION: This study suggests that macular thickening, as measured by the Stratus OCT, may spontaneously decrease in some patients with more severe CSME over the course of the day, and it confirms previous findings. However, in our study, the entity of this decline was relatively small and not relevant from a clinical standpoint.     

Macular electroretinograms and contrast sensitivity as sensitive detectors of early maculopathy

Eighteen patients with early maculopathies of various etiologies were tested with pattern and focal electroretinograms (macular ERGs), with high (400 cd/M²) and moderate (40 cd/M²) stimulus intensities and a four-alternative forced choice (4AFC) contrast sensitivity test in addition to intensive clinical examinations.High spatial frequency contrast sensitivity loss on the 4AFC test was the most striking and consistent feature of all cases. The only eyes not outside normal contrast sensitivity limits were three in which diagnosis was uncertain and the patients had not recognized any problem, including two marginal solar burns. Maculopathy also substantially reduced macular ERG amplitides. Criterion scores on these tests separated patients from normals more effectively than other noninvasive procedures and only missed one eye detected by contrast sensitivity. Latencies were affected but the delays were of no clinical significance in the individual case. Stimulus intensity was not critical.The results indicate that contrast sensitivity testing and macular ERGs are very reliable indices of central visual dysfunction at a stage when visible macular changes are too subtle for confident diagnosis. Contrast sensitivity has appeal because of its reliability, objectivity, simplicity, and noninvasive nature. It is equally applicable to children and adults. Pattern and focal ERGs can establish that the visual deficit has a retinal origin and can provide the most reliable objective confirmation.