Severe course of cutaneous melanoma associated paraneoplastic retinopathy

Melanoma-associated retinopathy

Melanoma-associated retinopathy (MAR) is a rare paraneoplastic autoimmune manifestation of cutaneous malignant melanoma. Patients classically present with acute onset night blindness, positive visual phenomena and visual field defects, and typically have significantly reduced quality of life as a result. Early recognition of MAR is of prognostic significance as it can precede the diagnosis of primary or metastatic malignant melanoma, and early treatment can lower the risk of irreversible immunological damage to the retinal cells with improved visual outcomes. The focus of our review article is therefore to raise awareness of MAR and present the latest evidence relating to the investigation and management of this condition.

ISCEV extended protocol for the photopic On-Off ERG

The International Society for Clinical Electrophysiology of Vision (ISCEV) standard for full-field electroretinography (ERG) describes a minimum procedure, but encourages more extensive testing. This ISCEV extended protocol describes an extension to the ERG standard, namely the photopic On-Off ERG, and outlines common clinical applications. A light stimulus duration of 150-200 ms is used in the presence of a rod-suppressing background to elicit cone-driven On- and Off-system ERG components. The On-response occurs after the stimulus onset and has a negative a-wave and positive b-wave. The Off d-wave is a positive component evoked by stimulus offset. Common diagnoses that may benefit from additional photopic On-Off ERG testing include retinal dystrophies and retinal disorders that cause dysfunction at a level that is post-phototransduction or post-receptoral. On-Off ERGs assess the relative involvement of On- and Off-systems and may be of use in the diagnosis of disorders such as complete and incomplete congenital stationary night blindness (complete and incomplete CSNB), melanoma-associated retinopathy, and some forms of autoimmune retinopathy. The photopic On-Off ERGs may also be useful in X-linked retinoschisis, Batten disease, Duchenne muscular dystrophy, spinocerebellar degeneration, quinine toxicity, and other retinal disorders.

The diagnostic usefulness of the negative electroretinogram

The definition of the negative response of the full field electroretinogram is the presence of a b-wave with less amplitude than the a-wave (b/a ratio<1) in the combined response of cones and rods. The presence of this pattern reflects an alteration in the bipolar cells, the Müller cells, or in the transmission of the stimulus from the photoreceptors to the bipolar cells, with preserved photoreceptor function. This finding can be seen bilaterally and symmetrically in different hereditary conditions, such as congenital stationary night blindness, juvenile X-linked retinoschisis, and Duchenne and Becker muscular dystrophies. On the other hand, it can also be found unilaterally (or asymmetrically) in acquired pathologies, such as some types of immuno-mediated retinitis (Birdshot retinochoroiditis), autoimmune retinopathies, cancer/melanoma associated retinopathy, or retinal toxicity. The objective of this review is to summarise the characteristics of the pathologies in which this finding can be observed, in order to highlight its usefulness in the differential diagnosis of retinal conditions.

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.

Autoantibodies in melanoma-associated retinopathy target TRPM1 cation channels of retinal ON bipolar cells

Melanoma-associated retinopathy (MAR) is characterized by night blindness, photopsias, and a selective reduction of the electroretinogram b-wave. In certain cases, the serum contains autoantibodies that react with ON bipolar cells, but the target of these autoantibodies has not been identified. Here we show that the primary target of autoantibodies produced in MAR patients with reduced b-wave is the TRPM1 cation channel, the newly identified transduction channel in ON bipolar cells. Sera from two well characterized MAR patients, but not from a control subject, stained human embryonic kidney cells transfected with the TRPM1 gene, and Western blots probed with these MAR sera showed the expected band size (∼180 kDa). Staining of mouse and primate retina with MAR sera revealed immunoreactivity in all types of ON bipolar cells. Similar to staining for TRPM1, staining with the MAR sera was strong in dendritic tips and somas and was weak or absent in axon terminals. This staining colocalized with GFP in Grm6-GFP transgenic mice, where GFP is expressed in all and only ON bipolar cells, and also colocalized with Gα(o), a marker for all types of ON bipolar cells. The staining in ON bipolar cells was confirmed to be specific to TRPM1 because MAR serum did not stain these cells in a Trpm1(-/-) mouse. Evidence suggests that the recognized epitope is likely intracellular, and the sera can be internalized by retinal cells. We conclude that the vision of at least some patients with MAR is compromised due to autoantibody-mediated inactivation of the TRPM1 channel.

Cancer-Induced, Immune-Mediated Ocular Degenerations

The means whereby vision can be lost from a disease located distant from the eye include autoimmunity, with sensitization resulting from extraocular stimuli, a process illustrated here by the immunologic confusion caused by cancers. The uncontrolled proliferation of malignancies commonly involves the expression of components of the central nervous system, but a damaging loss of tolerance is rare. When autoimmunity does develop, organ-specific antigens are more often involved than the more generalized and widely disseminated common neuronal components. A focus upon a single antigen is typical of the immune-mediated paraneoplasia, a collection of syndromes identified by unusual antibody reactions. This review provides an outline of the immunologic trail that led to the recognition of autoimmunity in paraneoplastic ocular degenerations, how specific antibody reactions aid in diagnosis, and the possibility of including antibodies in modes for sight-saving intervention. 'Those who do not know history are destined to repeat it'.

Phenotypic variability and long-term follow-up of patients with known and novel PRPH2/RDS gene mutations

PURPOSE

To describe the phenotypic variability in 22 patients with PRPH2 gene mutations and to report six novel mutations.

DESIGN

Retrospective study.

METHODS

Clinical examinations included color vision testing, perimetry, fundus autofluorescence (FAF), fluorescein angiography, optical coherence tomography (OCT), and full-field and multifocal electroretinography (International Society for Clinical Electrophysiology of Vision standards). Blood samples were taken for deoxyribonucleic acid (DNA) extraction and mutation screening was performed by direct sequencing of polymerase chain reaction amplicons.

RESULTS

Eleven unrelated patients and four unrelated families each with two affected members as well as one family with three affected members were examined. Diagnoses included central areolar choroidal dystrophy (CACD; n = 9), autosomal dominant retinitis pigmentosa (adRP; n = 7), adult vitelliform macular dystrophy (n = 3), and cone-rod dystrophy (CRD; n = 3). FAF was abnormal in all patients and showed various retinal pigment epithelial alterations, in CACD with a speckled FAF pattern. OCT revealed reduced retinal thickness, mostly in CACD, subretinal lesions, macula edema, or was normal. Follow-up (n = 12; range, 1.3 to 26 years) showed a slow progression of the retinal dystrophies. DNA testing revealed previously reported PRPH2 mutations in two families and eight individuals of whom two carried the same mutation but had different phenotypes. Novel PRPH2 mutations were detected in two families with adRP, in identical twins with CACD, and in each of an individual with CACD, CRD, and adRP.

CONCLUSIONS

This series describes the broad spectrum of phenotypes associated with PRPH2 mutations. FAF and OCT are helpful tools for diagnosis and evaluation of disease progression. We report novel PRPH2 mutations in patients with CACD, CRD, and adRP.

Central and Paracentral Visual Field Defects and Driving Abilities

The effect of central and paracentral visual field defects on driving abilities has until now received little attention. To date studies and surveys have concentrated on visual acuity and peripheral field loss. Here we summarise for the first time those diseases causing central visual field defects likely to be associated with binocular visual acuity adequate for driving.

Autoimmune retinopathy: a review and summary

Three main forms of autoimmune retinopathy (AIR) have been identified over the last 15 years: cancer-associated retinopathy (CAR), melanoma-associated retinopathy (MAR), and nonneoplastic autoimmune retinopathy (npAIR). In this chapter, the term AIR will be used to encompass all three disorders where there is commonality to their features. Complicating the issue is that AIR can be a secondary complication of other conditions such as retinitis pigmentosa, ocular trauma, birdshot retinopathy, acute zonal occult outer retinopathy (AZOOR), or multiple evanescent white dot syndrome (MEWDS). The many forms of AIR tend to have common clinical features despite the fact that there has been no uniform set of anti-retinal antibodies circulating in these patients. Patients tend to have a wide variance of anti-retinal antibody activity often with three to six different antibodies found on immunoblots. Patients typically present with a sudden onset of photopsia, rapid visual loss, and abnormal electroretinograms (ERGs). Most patients have a panretinal degeneration without pigment deposits.

The negative ERG: clinical phenotypes and disease mechanisms of inner retinal dysfunction

Inner retinal dysfunction is encountered in a number of retinal disorders, either inherited or acquired, as a primary or predominant defect. Fundus examination is rarely diagnostic in these disorders, although some show characteristic features, and careful electrophysiological assessment of retinal function is needed for accurate diagnosis. The ERG in inner retinal dysfunction typically shows a negative waveform with a preserved a-wave and a selectively reduced b-wave. Advances in retinal physiology and molecular genetics have led to a greater understanding of the pathogenesis of these disorders. This review summarizes current knowledge on normal retinal physiology, the investigative techniques used and the range of clinical disorders in which there is predominantly inner retinal dysfunction.

Eccentricity-dependent changes in local onset and offset responses in patients with progressive cone dystrophy

Shinoda and colleagues hypothesized that patients with cone dystrophy (CD) might suffer from a selective ON-system deficit, based on the local nature of the disease [Shinoda, K, Ohde, H, Inoue, R, Ishida, S, Mashima, Y, & Oguchi, Y (2002). ON-pathway disturbance in two siblings. Acta Ophthalmologica Scandinavica, 80, 219-223]. The purpose of the current study was to test this hypothesis by examining onset and offset responses as a function of eccentricity in a group of patients with CD using long-duration LED stimuli. Nine patients with CD participated in this study (mean age of 36.1 years and visual acuity 20/200). For this study, the following measures were obtained: Humphrey threshold visual fields, standard multifocal ERGs (mfERGs) as well as mfERGs to long duration stimuli recorded using the Retiscan stimulator (Roland Instruments). This display contained 61 scaled hexagons and the LEDs were on for 100ms (180cd/m(2)) and off for 100ms. In addition, standard full-field photopic and flicker ERGs using Ganzfeld stimulation were obtained. For the control subjects, the onset responses were larger than the offset responses at all eccentricities; whereas for the patients, there was overlap between the amplitudes of the onset and offset responses. For the patients, the amplitude ratios (relative to the control data) indicated that the difference between the onset and offset responses was greatest for the central-most ring and this difference decreased with increasing eccentricity. For the onset responses, Humphrey thresholds and mfERG amplitudes, performance was poorest for the center ring and best for the most peripheral ring; for the offset responses, the opposite pattern of results was obtained. The differences in the pattern of results in the long duration mfERG data are consistent with a selective loss of the onset responses in our patient population.

Surveillance of the eye and vision in clinical trials of CP-675,206 for metastatic melanoma

PURPOSE

To determine the ocular safety of CP-675,206 (Pfizer, New York, New York, USA), a fully human anti-cytotoxic T lymphocyte-associated antigen 4 monoclonal antibody in clinical trials of immunotherapy of metastatic melanoma.

DESIGN

Prospective, nonrandomized study of the eye and vision in phase I/II clinical trials of CP-675,206 in metastatic melanoma conducted at the University of California, Los Angeles.

METHODS

Patients with regional or distant metastatic melanoma were enrolled in phase I/II clinical trials evaluating the safety and antitumor efficacy of CP-675,206 alone or in combination with melanoma antigen peptide-pulsed dendritic cell vaccines. Ophthalmic evaluation was performed at the onset of CP-675,206 immunotherapy (baseline evaluation), two months or more after the onset of CP-675,206 immunotherapy (end-study evaluation), and at two- to three-month intervals thereafter in patients who continued to receive CP-675,206 immunotherapy (poststudy evaluation). Baseline and end-study evaluations included comprehensive ophthalmic examination, psychophysical and electrophysiologic visual function assessment, fundus photography, fluorescein angiography, and visual function assessment.

RESULTS

Twenty patients with metastatic melanoma arising from the skin, mucosa, eye, or unknown site were evaluated. Systemic toxicity attributed to CP-675,206 included dermatologic manifestations, diarrhea, and autoimmune hepatitis with panhypopituitarism. A subset of patients receiving CP-675,206 demonstrated antitumor efficacy with partial response or complete response of metastatic melanoma. Comparison of ophthalmic baseline with end-study evaluations in all 20 patients and limited-term poststudy evaluations showed no adverse effect of CP-675,206 immunotherapy on the eye or vision.

CONCLUSIONS

In this study, CP-675,206 immunotherapy for metastatic melanoma did not adversely affect the eye or vision.

Frequency of colour vision deficiencies in melanoma patients: results of a prospective comparative screening study with the Farnsworth panel D 15 test including 300 melanoma patients and 100 healthy controls

Patients with melanoma may experience a variety of different vision symptoms, in part associated with melanoma-associated retinopathy. For several melanoma patients with or without melanoma-associated retinopathy, colour vision deficiencies, especially involving the tritan system, have been reported. The frequency of colour vision deficiencies in a larger cohort of melanoma patients has not yet been investigated. The aim of this study was to investigate the frequency of colour vision deficiencies in melanoma patients subject to stage of disease, prognostic factors such as tumour thickness or Clark level, S100-beta and predisposing diseases that may have an impact on colour vision (hypertension, diabetes mellitus, glaucoma or cataract). Three hundred melanoma patients in different tumour stages and 100 healthy age-matched and sex-matched controls were examined with the saturated Farnsworth panel D 15 test. Seventy out of 300 (23.3%) melanoma patients and 12/100 (12%) controls showed pathologic results in colour testing. This discrepancy was significant (P < 0.016; odds ratio = 2.23, 95% confidence interval 1.15-4.32). Increasing age was identified as a highly significant (P = 0.0005) risk factor for blue vision deficiency. Adjusting for the age and predisposing diseases, we could show that melanoma was associated with the risk of blue vision deficiency. The frequency of blue vision deficiency in 52/260 melanoma patients without predisposing diseases (20%) compared with 4/78 controls without predisposing diseases (5.1%) differed significantly (odds ratio 4.441; confidence interval 1.54-12.62; P < 0.004). In 260 melanoma patients without predisposing diseases, blue vision deficiency, as graded on a 6-point scale, showed a weak positive correlation (Spearman) with tumour stage (r = 0.147; P < 0.01), tumour thickness (r = 0.10; P = 0.0035), Clark level (r = 0.12; P = 0.04) and a weak negative correlation with time since initial diagnosis (r = -0.11; P = 0.0455). Blue vision deficiency is associated with melanoma, but is only weakly related to stage of disease. Although we saw a positive correlation with well-known prognostic markers, such as tumour thickness and Clark level, blue vision deficiency as assessed by the Farnsworth panel D 15 test in general is inappropriate as a marker of tumour progression. For the use of blue vision deficiency in melanoma patients without predisposing diseases, a diligent test performance and interpretation is very important.

Clinical disorders affecting mesopic vision

Vision in the mesopic range is affected by a number of inherited and acquired clinical disorders. We review these conditions and summarize the historical background, describing the clinical characteristics alongside the genetic basis and molecular biological mechanisms giving rise to rod and cone dysfunction relevant to twilight vision. The current diagnostic gold standards for each disease are discussed and curative and symptomatic treatment strategies are summarized.

Choroideremia: variability of clinical and electrophysiological characteristics and first report of a negative electroretinogram

PURPOSE

To analyze the variability of clinical and electrophysiological characteristics in X-linked choroideremia and provide the first report of a negative electroretinogram in choroideremia.

DESIGN

Retrospective study.

PARTICIPANTS

The records of 18 male patients with choroideremia and 8 female carriers were evaluated.

METHODS

The data were reviewed regarding visual acuity (VA), color vision, perimetry, fundus autofluorescence, and full-field electroretinography (according to standards of the International Society for Clinical Electrophysiology of Vision).

MAIN OUTCOME MEASURES

Morphological and functional phenotype characteristics, fundus autofluorescence, electroretinography, and Rab escort protein 1 (REP-1) mutations.

RESULTS

Four unrelated families with choroideremia (9 affected males, 7 carriers) and 10 unrelated individuals (9 affected males, 1 carrier) were included. Mutational analysis, performed in 2 families and 3 individual males, revealed REP-1 mutations in all except 1 male. The age of the males ranged from 5.9 to 63.0 years (mean, 33.9), and VA ranged from hand movements to 1.0 (median, 0.7). Fundus autofluorescence (n = 7) showed defects in the retinal pigment epithelium in all males. Electroretinography (n = 13) was almost undetectable in 6 males and reduced in 6, indicating a rod-cone dystrophy. A further male showed a negative electroretinogram, with a b:a wave ratio of 0.5. Visual acuity of the 8 carriers (age, 4.8-56.8 years [mean, 24.0]) ranged from light perception to 1.2 (median, 1.0). Light perception was present in 1 carrier manifesting choroideremia with distinct chorioretinal atrophy. Pigmentary stippling, seen in the other carriers, was seen in fundus autofluorescence (n = 1) with a distinct speckled pattern. Electroretinograms were normal in 6 of 7 and reduced in the manifesting carrier. Defects in color vision and visual field were found in affected males and in the female carriers.

CONCLUSIONS

The phenotype of choroideremia presents with high variability. In addition to the previously reported findings, we observed a negative electroretinogram, indicating a postreceptoral retinal dysfunction, in 1 affected male; severe course of choroideremia with early blindness in 1 manifesting carrier; color vision deficits in the majority of affected males and carriers; and characteristic alterations in fundus autofluorescence.

ON- and OFF-response of the photopic electroretinogram in relation to stimulus characteristics

The aim of this study was to explore the effect of stimulus duration, stimulus intensity, stimulus wavelength and background luminance on the amplitude and waveform of the ON- (b-wave) and OFF- (d-wave) response of the photopic ERG. The following parameters were used in this study: stimulus duration from 5 to 200 ms, the flash intensities from 0.4 to 2.1 log cd s/m2, the background luminance from 20 to 50 cd/m2 and stimulus wavelengths 460, 508 and 667 nm. Prolonging the stimulus duration from 75 to 200 ms did not influence the amplitudes of a-, b- and d-waves significantly. Higher stimulus intensities (1.9 log cd s/m2) broadened the b-wave and increased variability of its implicit time. With a brighter background (50 cd/m2) the b-wave did not broaden and its optimal amplitude was preserved. Stimuli of longer wavelengths (667 nm) significantly reduced the d-wave amplitude. Our results suggest that high intensities and longer wavelengths (red) may not be suitable stimulus parameters in the routine clinical ON- and OFF-response recording.

Dysfunction of transmission in the inner retina: incidence and clinical causes of negative electroretinogram

BACKGROUND

Only limited data exist on the incidence of negative electroretinograms (ERG) in clinical practice. The purpose of this study is therefore to determine the incidence and clinical causes of a negative ERG in a tertiary care centre focused on inherited and acquired retinal degenerations.

METHODS

All ERGs recorded (in accordance with ISCEV standards) in our electrophysiological laboratory from 1992 to 2004 were retrospectively reviewed. The negative ERGs (criterion: ERG with b:a wave ratio<or=1 in the scotopic standard combined response in at least one eye) were analysed in the context of further clinical results. The photopic ON- and OFF-responses were recorded with long duration (200 ms) stimuli.

RESULTS

A total of 1999 ERGs from 1644 patients were performed during the study period. 47/1644 patients (2.9%) presented with a negative ERG and were included in the study. Clinical diagnoses included inherited retinal dystrophies [X-linked congenital retinoschisis (XRS) (n=17), congenital stationary night blindness (CSNB) (n=6), retinitis pigmentosa (RP) (n=6), cone (-rod) dystrophy (n=5), choroideremia (n=1), Müller cell sheen dystrophy (MCSD) (n=1)] and acquired retinopathies (melanoma-associated retinopathy (MAR) (n=1), vigabatrin retinotoxicity (n=1)). In nine patients a definitive diagnosis could not be established. Unilateral negative ERGs were seen in 10/37 patients where ERG was bilaterally recorded. The fellow eye presented with a b:a wave ratio >1 (8 eyes) or ERG responses were not detectable (2 eyes). Photopic ON- and OFF-responses were recorded in 38 eyes of 29 patients and 32/38 eyes presented with a negative ERG. The ON-response was reduced in 25/32 eyes, whereas the OFF-response was reduced in only 11/32 eyes.

CONCLUSIONS

The incidence of a negative ERG can differ between the laboratories depending on the causes for ERG recording and was in our laboratory 2.9% in a consecutive series of patients with inherited or acquired retinal degenerations. A disorder characteristically associated with negative ERG (e.g. XRS, CSNB, MAR) was diagnosed in 53% of these patients, whereas in 47% the negative ERG indicated an unexpected post-receptoral dysfunction, e.g. in cone (-rod) dystrophy or RP. The ON-bipolar pathway was affected in most cases.

Recording of both VEP and multifocal ERG for evaluation of unexplained visual loss electrophysiology in unexplained visual loss

The purpose of this retrospective study was to determine the relevance of both visual-evoked potentials (VEP) and multifocal electroretinography (mfERG) to evaluate unexplained visual loss. Seventy-two consecutive patients (1996-2002) with visual disturbances of unknown origin underwent both VEP and mfERG (ISCEV standard). The mean age was 42.4 years (11.8-74.5) and median visual acuity 0.5 (no light perception - 1.0). Symptoms reported included visual acuity loss (n=69), visual field defects (n=11), disturbances of colour vision, light or dark adaptation (n=10). VEP and mfERG were normal in 43% (n=31). Both VEP and mfERG were pathological in 24% (n=17). In a further 18% (n=13) only the mfERG was pathological and in 15% (n=11) only the VEP was pathological. Macular dysfunction as detected with mfERG was present in 73% of 41 patients with at least one pathological test. Neuroimaging (MRI, CCT) and/or neurological examination was performed in 27/72 patients (38%), to account for unexplained visual loss, prior to the electrophysiological tests; these were normal in all patients. Electrophysiological tests revealed disturbances of the post-retinal visual pathway in only 3/27 patients. In 12/27 patients, mfERG revealed a macular disorder; in a further 12/27 patients VEP and mfERG were normal. The combined evaluation of VEP and mfERG is useful both to establish the area of dysfunction and the normality of the visual system. Electrophysiological testing prior to neuroimaging is recommended for patients where clear clinical signs of cerebral disorders are not evident. This reduces the frequency of unnecessary neuroimaging and associated radiation exposure.

SEREX identification of new tumor antigens linked to melanoma-associated retinopathy

Metastatic melanoma still has a very poor prognosis since it withstands conventional therapies like surgery or chemotherapy. A paraneoplastic autoimmune manifestation of this disease is melanoma-associated retinopathy (MAR). MAR has been associated with prolonged survival and may be an early marker of tumor progression. By screening a retina and a melanoma cDNA phage library by SEREX using sera of patients suffering from melanoma and, in some cases, clinical symptoms of MAR, we identified 20 new antigens (HD-MM-28-47), of which 14 clones had high homology to well-known genes. Six of these genes had previously been associated with retina: rhodopsin, visual arrestin, MEK1, SRPX, BBS1 and galectin-3. Individual clones were recognized by up to 43% of patients' sera, while sera of healthy volunteers were negative except in 2 cases. The expression profile of the antigens identified on the basis of homologous EST database entries in healthy tissues was ubiquitous to differential. Using RT-PCR, we found frequent expression of preselected antigens in melanoma cell lines. For rhodopsin, this could be quantified by quantitative PCR. Retinal proteins were recognized by serum antibodies of melanoma patients but not healthy controls. The role of these antigens in MAR awaits further investigation. (Supplementary material for this article can be found on the International Journal of Cancer website at http://www.interscience.wiley.com/jpages/0020-7136/suppmat/index.html.)

MORPHOLOGY AND FUNCTIONAL CHARACTERISTICS IN ADULT VITELLIFORM MACULAR DYSTROPHY

PURPOSE

Detailed morphologic and functional evaluation of adult vitelliform macular dystrophy (AVMD).

METHODS

The records of 61 consecutive AVMD patients (inclusion criterion: vitelliform lesion smaller than one disk diameter at least in one eye) were evaluated retrospectively regarding visual acuity, color vision, perimetry, retinal pigment epithelium (RPE) autofluorescence, fluorescein angiography, electro-oculography, full-field and multifocal electroretinography, and molecular genetic evaluation of the VMD2 and RDS/peripherin genes.

RESULTS

The mean age of subjects was 54.6 years. Visual loss was variable (median, 0.6; range, 1.25-0.05). Color vision and visual field were normal in about half of the patients but presented defects with high variability in the remaining patients. Autofluorescence findings showed increased fluorescence within the foveal yellow lesion in 76%. In the majority of eyes, the amplitude of the 30 Hz flicker response of the full-field electroretinogram (72%) and the central P1 amplitude of the multifocal electroretinogram (63%) were reduced. Mutational analyses revealed a potentially disease-associated mutation in the RDS/peripherin gene in one patient.

CONCLUSION

AVMD is characterized by late onset, slow progression, good prognosis, and high variability of morphologic and functional abnormalities resulting frequently in misdiagnosis. Autofluorescence findings indicate lipofuscin accumulation in the yellow lesion. Electroretinography revealed a generalized cone system dysfunction with increasing severity toward the fovea.

Surveillance of the eye and vision in a clinical trial of MART1-transformed dendritic cells for metastatic melanoma

PURPOSE

To report the protocol for surveillance of the eye and vision in a clinical trial of MART1-transduced dendritic cells for metastatic melanoma.

METHODS

In a phase I/II clinical trial of dendritic cell-based genetic immunotherapy for metastatic cutaneous melanoma, ophthalmic evaluation is performed prior to immunization (Baseline Evaluation), 56+/-7 days after first vaccination (mid-study evaluation), when dendritic cell injections are complete 112+/-7 days after first vaccination (end-study evaluation) and 168+/-7 days after first vaccination (post-study evaluation).

RESULTS

The protocol for baseline, mid-study and end-study evaluations of the eye and vision includes ophthalmic history, comprehensive ophthalmic examination, psychophysical and electrophysiological visual function assessment, fundus photography and fluorescein angiography. Post-study evaluation consists of the 25-item visual functioning questionnaire augmented to elicit autoimmune manifestation with complete ophthalmic evaluation if vision-related symptoms or abnormalities are noted during or after the vaccination.

CONCLUSION

Limited adverse effects on the eye and vision have been reported in melanoma immunotherapy trials, although this novel mode of therapy has the potential to induce melanoma paraneoplastic syndromes known to severely impair vision. Therefore, surveillance of the eye and vision should be considered in melanoma immunotherapy trials.

Paraneoplastic syndromes associated with visual loss

PURPOSE OF REVIEW

The recent literature was reviewed to analyze the developments in the diagnosis, pathogenesis, and immunology of this group of paraneoplastic syndromes. Clinical features and pathologic findings are summarized.

RECENT FINDINGS

The mechanism of cell death in cancer-associated retinopathy appears to occur through apoptotic pathways. Caspase inhibitors and a calcium antagonist have been used in animal models to block or suppress the effect of the antirecoverin antibodies on the retina with significant response. These agents are possible treatment options for cancer-associated retinopathy. Aberrant expression of recoverin by tumor cells does not necessarily induce antirecoverin antibodies and cancer-associated retinopathy. Many tumors, not just those producing the clinical picture of cancer-associated retinopathy, have been shown to express recoverin. Recoverin appears to play a functional role in tumor cells, and antirecoverin antibodies may have tumor-suppressing effects. Further research into this area may help design epitope-based immunotherapy for patients with recoverin-expressing tumors. Further evidence has emerged to support the initial observation that depolarizing bipolar cells are the likely retinal target in melanoma-associated retinopathy. Intravitreal injection of melanoma-associated retinopathy serum produced electroretinogram changes in animals very similar to the clinical findings in humans. Many new antibodies and antigens had been discovered to be linked to various paraneoplastic syndromes. Anti-collapsing response-mediating protein-5 is likely to be an important one; it was found to be the second most common autoantibody related to paraneoplastic neurologic syndromes.

SUMMARY

Further research into the functional role of recoverin in cancer cells may advance our understanding in cancer immunology. Immunotherapy may be possible if a specific epitope of recoverin can be found to contain the antigenic site for antitumor antibodies and not cross-react with retinal antigens. Research into the pathogenesis of the other paraneoplastic syndromes is required for a better understanding and treatment of these rare conditions. The missing link between primary cutaneous melanoma and uveal melanocytes still eludes investigators in bilateral diffuse uveal melanocytic proliferation. The discovery of the missing link may provide us with some understanding of the development of uveal melanoma.

Melanoma-associated retinopathy: high frequency of subclinical findings in patients with melanoma

BACKGROUND

Melanoma-associated retinopathy (MAR) is a paraneoplastic syndrome with symptoms of night blindness, light sensations, visual loss, defect in visual fields, and reduced b-waves in the electroretinogram. Patients with MAR often suffer from a sudden onset of ocular symptoms that are believed to result from antibody production against melanoma-associated antigens that cross-react with corresponding epitopes on retinal depolarizing bipolar cells.

OBJECTIVES

To correlate the frequency of subclinical symptoms suggestive of MAR in melanoma patients to different stages of disease, patient age, type and thickness of the primary tumour, form of therapy, S-100 level and tumour burden.

METHODS

We analysed 28 patients with melanoma in stages I-IV (according to the American Joint Committee on Cancer tumour classification) for the presence of subclinical MAR symptoms using scotopic electroretinography, static and kinetic perimetry and nyctometry.

RESULTS

Seven patients had clinical signs and symptoms consistent with MAR, 18 had some indications, while the remaining three had none. We found no correlation between clinical symptoms and stage of disease, tumour burden or S-100 level, but findings suggestive of MAR were observed more frequently in advanced stages of disease.

CONCLUSIONS

Subclinical retinal involvement characteristic of MAR appears to be more common than previously suspected in patients with cutaneous malignant melanoma. Our findings in this small cohort seem to indicate that the percentage of patients with symptoms suggestive of MAR is higher in advanced stages of disease. Further clinical studies are required to evaluate if the presence of subclinical symptoms suggestive of MAR is correlated with a worse prognosis and a shortened progression-free and overall survival.

Paraneoplastic retinopathies and optic neuropathies

Unusual neuro-ophthalmologic symptoms and signs that go unexplained should warrant a thorough investigation for paraneoplastic syndromes. Although these syndromes are rare, these clinical manifestations can herald an unsuspected, underlying malignancy that could be treated early and aggressively. This point underscores the importance of distinguishing and understanding the various, sometimes subtle, presentations of ocular paraneoplastic syndromes. Outlined in this review article are diagnostic features useful in differentiating cancer-associated retinopathy, melanoma-associated retinopathy, and paraneoplastic optic neuropathy. These must also be distinguished from non-cancer-related eye disorders that may clinically resemble cancer-associated retinopathy. The associated antibodies and histopathology of each syndrome are presented to help in the understanding of these autoimmune phenomena. Treatment outcomes from reported cases are summarized, and some potential novel immunotherapies are also discussed.

Non-cancerous ophthalmic clues to non-ocular cancer

This survey reviews selected medical disorders in which the ophthalmologist has a unique opportunity of anticipating the existence of asymptomatic, life-threatening disease simply by recognizing that certain benign conditions involving the eye or adnexa represent clues to occult non-ocular cancer and other neoplasias. Having knowledge that these clues are associated with specific types of neoplasia, the ophthalmologist can then initiate a goal-directed oncologic investigation designed to identify the underlying neoplasm with the hope of providing potentially life-saving therapy. The survey is organized to feature each clue separately. The clinical characteristics of the clue are described and illustrated with color photographs when possible. A discussion reviews associated malignancies and other important medical features. The survey begins with clues expressed anteriorly in the lids, progressively reviewing those clues located more posteriorly, concluding with clues involving the retinal pigment epithelium and choroid.

Clinical and immunologic characteristics of melanoma-associated retinopathy syndrome: eleven new cases and a review of 51 previously published cases

OBJECTIVE

To evaluate the signs, symptoms, and immune responses of patients with melanoma-associated retinopathy (MAR) syndrome.

MATERIALS AND METHODS

We reviewed the clinical and immunologic findings of 62 MAR syndrome patients. They include 25 patients from our institution (11 not previously reported) and 37 patients reported from other institutions.

RESULTS

There were 33 men and seven women (no gender information is available for the remaining 22 cases). Age at onset of the visual disturbance averaged 57.5 years (range, 30-78). Visual acuity of 20/60 or better was initially present in 82%. Fundus examination was normal in 44%, optic disc pallor was present in 23%, and retinal vessel attenuation was present in 30%. Vitreous cells were present in 30%. The latency from melanoma diagnosis to recognition of MAR syndrome averaged 3.6 years (range, 2 months to 19 years). Seven patients sustained visual improvement with various treatment regimens, especially with intravenous immunoglobulin and cytoreductive surgery (metastasectomy). Indirect immunohistochemical staining of the bipolar layer was typical, but several other retinal elements were also reactive. Tissue from a metastatic melanoma excised from one of the patients expressed antigens that reacted with antiretinal antibodies.

CONCLUSION

MAR syndrome demonstrates diverse clinical and immunologic features. Treatment, especially intravenous immunoglobulin and cytoreductive surgery (metastasectomy), improves vision in some cases.

Melanoma-associated retinopathy: does autoimmunity prolong survival?

PURPOSE

To discuss the autoimmune basis of melanoma-associated retinopathy (MAR) and its implications for management and prognosis.

METHODS

An unusual history of a woman with melanoma-associated retinopathy is presented in detail. A review of published reports and a summary of 19 reported cases of MAR provide a basis for discussion.

RESULTS

This case report and other published reports highlight a number of points regarding MAR including the male predominance, prolonged survival in several patients and lack of response to immunosuppression.

CONCLUSIONS

Melanoma-associated retinopathy may prolong the survival of patients with metastatic melanoma through the autoimmune response. Therefore, treatment of visual symptoms with immunosuppression needs to be considered carefully.

Pattern electroretinography (PERG) and an integrated approach to visual pathway diagnosis

The pattern electroretinogram (PERG) provides an objective measure of central retinal function, and has become an important element of the author's clinical visual electrophysiological practice. The PERG contains two main components, a positivity at approximately 50ms (P50) and a larger negativity at approximately 95ms (N95). The P50 component is affected by macular dysfunction with concomitant reduction in N95. The PERG therefore complements the Ganzfeld ERG in the assessment of patients with retinal disease. In contrast, the ganglion cell origins of the N95 component allow electrophysiological evaluation of ganglion cell function both in primary disease and in dysfunction secondary to optic nerve disease, where selective loss of N95 can be observed. Both macular dysfunction and optic nerve disease can give abnormalities in the visual evoked cortical potential (VEP), and the PERG thus facilitates more meaningful VEP interpretation. This review addresses the origins and recording of the PERG, and then draws on extensive clinical data from patients with genetically determined retinal and macular dystrophies, other retinal diseases and a variety of optic nerve disorders, to present an integrated approach to diagnosis.

The incidence of negative ERG in clinical practice

INTRODUCTION

A negative electroretinogram (ERG) is one in which there is a selective reduction in amplitude of the b-wave, such that it does not exceed that of the a-wave. The purpose of this study was to determine the incidence and clinical causes of negative ERGs at a tertiary referral centre. In addition, interesting and previously unreported aetiologies are described.

PATIENTS AND METHODS

Retrospective review of all ERGs done at Moorfields Eye Hospital from November 1995 to December 1998 under ISCEV standard conditions. Many patients had photopic ON- and OFF-response recording in addition to conventional ISCEV Standard ganzfeld ERG.

RESULTS

A total of 2,640 ERGs were performed during the study period. 128 cases (4.8%) showed a negative ERG. The causes, where a firm clinical diagnosis was possible, include X-linked juvenile retinoschisis, congenital stationary night blindness, central retinal artery occlusion, birdshot chorioretinopathy and melanoma-associated retinopathy (MAR). Unilateral negative ERG waveforms with normal fundal appearances were seen in 7 patients. Photopic ON- responses could be selectively affected.

CONCLUSIONS

The incidence of negative ERGs over a 34-month period presenting to a large tertiary centre was almost 5%. The presence of a negative ERG may be instrumental in demonstrating the site of visual dysfunction, with many cases showing minimal or no fundus abnormality. ON- and OFF-response recording yielded additional information regarding photopic post-receptoral/phototransduction function.

Electrophysiology in the investigation of acquired retinal disorders

Electrophysiological research on acquired retinal disorders, both common and rare, is reviewed. Age is a major factor influencing electroretinogram (ERG) and electro-oculogram (EOG) findings. Bipolar or Müller cell death in the aging retina could account for much of the amplitude decline that is observed with age. In diabetic retinopathy, the oscillatory potentials can monitor the progression of the disease and indicate neuronal alterations rather than diabetic angiopathy of the retina. Human ERG studies on glaucoma concentrated on ERG measures that are dominated by inner retinal contributions. It has been shown that the pattern ERG can serve as a predictor of ocular hypertension's progression to glaucoma. In retinal disorders caused by endogenous intoxication, such as hepatic retinopathy, or exogenous intoxication from chronic lead exposure, ERG changes give an objective measure of the damage and allow to study the pathophysiological mechanisms that are involved. Inflammations of the choroid and the retina affect the standard ERG when they are diffuse. In central serous chorioretinopathy, functional disturbances can be revealed not only in the photoreceptors but also in the middle and inner retinal layers with the use of focal stimuli. Choroidal melanoma leads to large reductions of the EOG light peak-to-dark trough ratio through its influence on the transepithelial potential of the retinal pigment epithelium (RPE). In cancer-associated retinopathy, both the rod and cone ERGs are reduced. However, selective cone dysfunction has been described. In melanoma-associated retinopathy, the long flash ERG may reveal a specific pathophysiological mechanism, namely the affection of the ON-pathway with preservation of the OFF-pathway. ERG measurements can reveal vitamin A deficiency and are altered in cases with a mutation in the gene for the retinol binding protein in which other organs are not affected. Photochemical damage to the retina from light emission by the operating microscope can be assessed by electrophysiological methods.

Ocular manifestations of systemic malignancies

Ocular manifestations of systemic malignancy are important for both the ophthalmologist and the internist to recognize because they may precede the diagnosis of cancer. This review of the current literature discusses the clinical manifestations, etiology, and potential therapeutic interventions for a group of visual paraneoplastic syndromes, including carcinoma-associated retinopathy and melanoma-associated retinopathy. These conditions are characterized by elevated serum levels of autoantibodies directed against tumor antigen that cross-react with retinal proteins, resulting in rod and cone dysfunction. The clinical presentation, site of origin, frequency, and intraocular distribution of tumors metastatic to the eye are also reviewed.

Clinical and immunocytochemical findings in a case of melanoma-associated retinopathy

OBJECTIVE

To describe an unusual case of melanoma-associated retinopathy (MAR).

DESIGN

Retrospective, observational case report and experimental study.

PARTICIPANTS

A 61-year-old man with a history of cutaneous melanoma, acquired bilateral central scotomas, and night blindness.

INTERVENTION

Serial full-field electroretinography (ERG) and Goldmann perimetry were performed. Serum was screened for cancer-associated retinopathy (CAR) antibodies by Western blotting. Sections of human and rat retina were examined by immunofluorescence microscopy to determine whether retinal cells were reactive with this patient's serum. A metastatic workup was performed.

MAIN OUTCOME MEASURES

Electroretinography, Goldmann visual field testing, and immunocytochemistry were performed.

RESULTS

The results were as follows: (1) The ERG showed a profound loss of the b-wave amplitude and a "negative" b-wave characteristic of congenital stationary night blindness; (2) a central scotoma and peripheral constriction were identified on Goldmann visual field tests; (3) as in other patients with MAR, bipolar cells in human and rat retinas were immunolabeled with this patient's serum; and (4) a previously unsuspected focus of metastatic melanoma was discovered.

CONCLUSIONS

Recognition of this condition may help to identify an occult focus of metastatic melanoma.

An electrophysiological follow-up study on acquired unilateral nyctalopia

PURPOSE

To describe the clinical picture and electrophysiological findings in acquired unilateral nyctalopia.

METHODS

A patient who had acquired unilateral visual loss with normal fundus was followed for a period of 2.5 years with basic ophthalmological examinations including standard electroretinogram and photopic on and off responses.

RESULTS

A 46-year-old woman suffered from acquired unilateral nyctalopia. She complained of photopsia and blurred vision in her left eye. The initial examination of the left eye showed 1+ cells in the anterior chamber and a granular appearance in the fovea. After 1 month of treatment she still complained of photopsia in her left eye. Ophthalmoscopy and fluorescein angiography revealed no abnormality in either eye. A bright flash electroretinogram (ERG) in the left eye was a negative shape. Photopic ERG elicited by a 150 ms stimulus showed a depressed b-wave and enhanced a- and d-waves in the left eye.

CONCLUSIONS

This ERG waveform suggested that the transmission between photoreceptor and on-bipolar cell might be affected by idiopathic retinal disease.

Cutaneous melanoma-associated paraneoplastic retinopathy: histopathologic observations

PURPOSE

To describe the retinal histopathology of paraneoplastic retinopathy associated with cutaneous melanoma.

METHODS

A 59-year-old man had visual loss attributable to paraneoplastic retinopathy and died of metastatic cutaneous melanoma. His eyes were studied by conventional histopathologic techniques.

RESULTS

Histopathologic examination of both eyes disclosed a marked reduction in the density of bipolar neurons in the inner nuclear layer; photoreceptor cell neurons in the outer nuclear layer were normal. Ganglion cells were present, although many showed evidence of transsynaptic atrophy.

CONCLUSION

The histopathologic changes observed are consistent with clinical, immunologic, and electrophysiologic data that implicate the bipolar cell as the major site of the paraneoplastic process in cutaneous melanoma-associated retinopathy.

Electrophysiological evaluation of visual loss in Müller cell sheen dystrophy

AIMS

To describe the clinical picture and electrophysiological findings in Müller cell sheen dystrophy, a recently reported retinal dystrophy.

METHOD

A basic ophthalmological evaluation as well as recording of standard electro-oculography and electroretinography were performed in one patient at the onset of visual loss and after 1 year of follow up.

RESULTS

A 61 year old woman presented with visual loss in the right eye. Multiple folds at the level of the internal limiting membrane were seen at the posterior pole in both eyes. Macular oedema was present in the right eye. The visual acuity of the right eye was 6/30 and of the left 6/9. A paracentral scotoma was found in the right eye. Electro-oculographic examination of both eyes gave normal results. Electroretinography (ERG) revealed reduced b-wave and flicker amplitudes in the right eye; these potentials were normal for the left eye. The ON response in the right eye was reduced and delayed; it was normal in the left eye. A further loss of visual function was noted 1 year later in the right eye, but the ophthalmoscopic findings were unchanged. The ERG of the right eye had a negative waveform when dark adapted. Light adapted responses showed an unusual delayed b-wave, broad and delayed ON and OFF responses and a missing flicker response, suggesting a Müller cell dysfunction. Light adapted responses were slightly reduced in the left eye.

CONCLUSIONS

Electrophysiological data indicate Müller cell dysfunction as a background of functional loss in Müller cell sheen dystrophy. This is in agreement with previously reported histological findings in this disorder.

Neurologic paraneoplastic syndromes

Several neurologic paraneoplastic disorders are believed to be caused by an autoimmune reaction against antigen(s) co-expressed by tumour cells and neurons. Of the paraneoplastic syndromes, the evidence for an autoimmune etiology is strongest for the Lambert-Eaton myasthenic syndrome, in which autoantibodies downregulate voltage-gated calcium channels at the presynaptic nerve terminal. For other syndromes, including cerebellar degeneration, multifocal encephalomyelitis, sensory neuronopathy, limbic encephalitis, opsoclonus-myoclonus, stiff person syndrome, and retinal degeneration, the autoimmune theory is supported by the presence of specific antineuronal antibodies. These antibodies serve as a useful diagnostic tool, but their actual role in causing neuronal injury and clinical disease remains unclear. Further understanding of immunopathogenesis awaits successful experimental models. Among different syndromes, a varied proportion of patients shows neurologic improvement with immunosuppressive treatments; it is likely that many patients have already suffered irreversible neuronal injury at the time of diagnosis.