Retinal findings in melanoma-associated retinopathy

Non-vasogenic cystoid maculopathies

Besides cystoid macular edema due to a blood-retinal barrier breakdown, another type of macular cystoid spaces referred to as non-vasogenic cystoid maculopathies (NVCM) may be detected on optical coherence tomography but not on fluorescein angiography. Various causes may disrupt retinal cell cohesion or impair retinal pigment epithelium (RPE) and Müller cell functions in the maintenance of retinal dehydration, resulting in cystoid spaces formation. Tractional causes include vitreomacular traction, epiretinal membranes and myopic foveoschisis. Surgical treatment does not always allow cystoid space resorption. In inherited retinal dystrophies, cystoid spaces may be part of the disease as in X-linked retinoschisis or enhanced S-cone syndrome, or occur occasionally as in bestrophinopathies, retinitis pigmentosa and allied diseases, congenital microphthalmia, choroideremia, gyrate atrophy and Bietti crystalline dystrophy. In macular telangiectasia type 2, cystoid spaces and cavitations do not depend on the fluid leakage from telangiectasia. Various causes affecting RPE function may result in NVCM such as chronic central serous chorioretinopathy and paraneoplastic syndromes. Non-exudative age macular degeneration may also be complicated by intraretinal cystoid spaces in the absence of fluorescein leakage. In these diseases, cystoid spaces occur in a context of retinal cell loss. Various causes of optic atrophy, including open-angle glaucoma, result in microcystoid spaces in the inner nuclear layer due to a retrograde transsynaptic degeneration. Lastly, drug toxicity may also induce cystoid maculopathy. Identifying NVCM on multimodal imaging, including fluorescein angiography if needed, allows guiding the diagnosis of the causative disease and choosing adequate treatment when available.

Autoimmune retinopathy with associated anti-retinal antibodies as a potential immune-related adverse event associated with immunotherapy in patients with advanced cutaneous melanoma: case series and systematic review

OBJECTIVE

To demonstrate the spectrum of autoimmune retinopathy (AIR) associated with immunotherapy for advanced cutaneous melanoma.

METHODS AND ANALYSIS

Retrospective chart review on patients with advanced cutaneous melanoma who developed AIR after initiating immunotherapy. Complete ophthalmic examination and relevant ancillary testing were performed on each patient. The presence of AIR-associated anti-retinal antibodies was confirmed by western blot and/or immunohistochemical staining. Ophthalmic and systemic outcomes after treatment for AIR were followed over time. A systematic review of AIR associated with immunotherapy for cutaneous or non-ocular mucosal melanoma was carried out in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Case 1 developed photopsia and nyctalopia with electroretinographic findings characteristic for melanoma-associated retinopathy 1 week after initiating ipilimumab/nivolumab immunotherapy. Case 2 experienced new severe bilateral visual field loss associated with anti-retinal and anti-optic nerve antibodies while on maintenance nivolumab immunotherapy. Case 3 developed decreased visual acuity due to acute exudative polymorphous vitelliform maculopathy within 2 weeks of initiating ipilimumab/nivolumab immunotherapy. All patients had concurrent extraocular immune-related adverse events in addition to the presence of anti-retinal antibodies on serological testing. 14 published cases of AIR associated with immunotherapy for cutaneous or non-ocular mucosal melanoma were identified and reviewed.

CONCLUSIONS

Immune checkpoint inhibition can trigger the development of AIR with varied clinical manifestations in patients with advanced cutaneous melanoma. This study highlights the need for close monitoring in cutaneous melanoma patients receiving immunotherapy who develop new visual symptoms with or without funduscopic changes, as well as the potential role for screening of patients prior to initiating immunotherapy.

[Melanoma-associated vitelliform retinopathy (a clinical case study)]

Melanoma-associated vitelliform retinopathy is a manifestation of paraneoplastic syndrome in skin melanoma. Paraneoplastic syndrome, while not being a tumor or a metastatic disease, is regarded as a tumor-associated disease related to extraocular localization of neoplasm. In this clinical case, the diagnosis of melanoma-associated vitelliform retinopathy was based on a combination of clinical, angiographic, autofluorescence and morphometric signs of bilateral lesion. Analysis of the case showed that in common oncological diseases and complaints of visual impairment, examination of eye fundus is mandatory in order to timely diagnose the changes associated with tumor lesion. Detection of bilateral lesions with oval grey-yellow multiple foci at the level of retinal pigment epithelium may indicate melanoma-associated vitelliform retinopathy that requires diagnostic search for skin melanoma. A complex of instrumental studies including fluorescent angiography, optical coherence tomography and autofluorescence with feature identification allowed establishing the correct diagnosis in the particular case.

Are Anti-Retinal Autoantibodies a Cause or a Consequence of Retinal Degeneration in Autoimmune Retinopathies?

Autoantibodies (AAbs) against various retinal proteins have been associated with vision loss in paraneoplastic and non-paraneoplastic autoimmune retinopathies (AR). There are two major paraneoplastic syndromes associated anti-retinal AAbs, cancer-associated retinopathy (CAR), and melanoma-associated retinopathy. Some people without a cancer diagnosis may present symptoms of CAR and have anti-retinal AAbs. The etiology and pathogenesis of those entities are not fully understood. In this review, we provide evidence for the role of AAbs in retinal death and degeneration. Studies of epitope mapping for anti-recoverin, anti-enolase, and anti-carbonic anhydrase II revealed that although patients' AAbs may recognize the same retinal protein as normal individuals they bind to different molecular domains, which allows distinguishing between normal and diseased AAbs. Given the great diversity of anti-retinal AAbs, it is likely some antibodies have greater pathogenic potential than others. Pathogenic, but not normal antibodies penetrate the target cell, reach their specific antigen, induce apoptosis, and impact retinal pathophysiology. Photoreceptors, dying by apoptosis, induced by other than immunologic mechanisms produce substantial amounts of metabolic debris, which consequently leads to autoimmunization and enhanced permeability of the blood-retinal barrier. AAbs that were made as a part of anti-cancer response are likely to be the cause of retinal degeneration, whereas others, generated against released antigens from damaged retina, contribute to the progression of retinopathy. Altogether, AAbs may trigger retinal degeneration and may also exacerbate the degenerative process in response to the release of sequestered antigens and influence disease progression.

Nonantibestrophin Anti-RPE Antibodies in Paraneoplastic Exudative Polymorphous Vitelliform Maculopathy

PURPOSE

A previous report demonstrated antibodies to bestrophin in paraneoplastic exudative polymorphous vitelliform maculopathy (PEPVM). Other cases demonstrated antibodies to different proteins in the retinal pigment epithelium (RPE). In this report, serum was analyzed to determine whether a patient with PEPVM and a reduced Arden ratio had developed autoantibodies to human Bestrophin-1 (Best1).

METHODS

Human embryonic kidney 293 cells (HEK293) were transfected with Best1 and stained with an antibody specific to Best1 (E6-6), or patient serum. Staining patterns were compared with those of untransfected cells stained with E6-6, patient serum, control serum, or secondary antibody alone. Western blots were performed using lysed RPE and stained with E6-6, patient serum, control serum, or secondary antibody alone.

RESULTS

Immunofluorescence staining of HEK-293 cells or HEK-293 cells expressing Best1 did not differ between patient and control sera or show a staining pattern consistent with recognition of Best1. Immunoblotting of human RPE lysate with patient serum did not identify Best1 (68 kDa) but did recognize a band at approximately 48 kDa that was absent in blots using control serum.

CONCLUSIONS

To our knowledge, this is the first report of PEPVM with an autoantibody to an approximately 48-kDa RPE protein, but previous reports have demonstrated autoantibodies to other RPE proteins, suggesting that autoantibody formation is an important component of PEPVM.

TRANSLATIONAL RELEVANCE

This research emphasizes the role that autoantibodies play in PEPVM. The fact that different autoantibodies appear to cause similar patterns demonstrates the heterogeneity of causes of vitelliform lesions.

Paraneoplastic retinopathy associated with systemic follicular cell lymphoma

The authors describe two rare cases of autoimmune retinopathy associated with follicular cell lymphoma, including a 54-year-old man who experienced nyctalopia for 1 year (patient 1) and a 59-year-old man who had bilateral loss of central vision for 6 months (patient 2). Visual field testing of patient 1 revealed nonspecific defects, and multifocal electroretinogram (ERG) testing showed mildly subnormal amplitudes more pronounced in the left than the right eye. Serologic testing detected antibodies against a 47-kD protein, presumed to be alpha-enolase. Goldmann perimetry of patient 2 showed dense central scotomas, and a full-field ERG revealed reduced amplitudes of bright scotopic responses. Serological testing yielded anti-bipolar cell antibodies. A variable presentation of autoimmune retinopathy can occur in the setting of follicular cell lymphoma. Disparate serum autoantibodies may have mediated the pathogenesis of retinal degeneration in these two patients and could explain the difference in course and severity of retinopathy.

Localized retinal manifestations of paraneoplastic autoimmune retinopathy

PURPOSE

Systemic neoplastic processes can affect the retina through autoimmune retinopathy. This process may present in a variety of patterns. A novel pattern of paraneoplastic autoimmune retinopathy has been described.

METHODS

Two patients presented with paraneoplastic vision changes. Optical coherence tomography and multifocal electroretinography were performed, which showed a unique focal retinal change in both patients. Case 1 is a 20-year-old woman with history of cutaneous melanoma. Case 2 is 67-year-old woman with history of breast cancer.

RESULTS

Both patients showed a localized area of foveal thinning that corresponded with areas of depression on multifocal electroretinography. Each tested positive for antiretinal antibodies.

CONCLUSION

This is a novel manifestation of paraneoplastic autoimmune retinopathy. Previously described cases have all affected the retina diffusely. These cases highlight the need to consider distant neoplastic processes when evaluating patient with similar presentations to those depicted here.

Paraneoplastic vitelliform retinopathy in a patient with treated choroidal melanoma

PURPOSE

To describe a peculiar case of paraneoplastic vitelliform maculopathy/retinopathy in a patient with treated choroidal melanoma.

METHODS

A case report of a 58-year-old woman with a history of treated choroidal melanoma 16 years before developing visual changes in the setting of metastatic choroidal melanoma.

RESULTS

We demonstrate bilateral, multifocal vitelliform subretinal lesions and focal, neurosensory retinal detachment associated with metastatic melanoma.

CONCLUSION

Paraneoplastic vitelliform maculopathy/retinopathy should be considered in patients with or without a history of melanoma, who have unexplained serous, vitelliform retinal detachments, especially with atypical or absence of leakage on fluorescein angiography.

Paraneoplastic vitelliform retinopathy: clinicopathologic correlation and review of the literature

Traditionally, the paraneoplastic retinopathies have been classified into two groups: melanoma-associated retinopathy (MAR) and cancer-associated retinopathy. MAR occurs in individuals with metastatic cutaneous or uveal melanoma and is characterized by nyctalopia, photopsias, and variable vision loss. In most cases, the fundus is essentially normal in appearance. More recently, there have been multiple reports of a MAR-like retinopathy with associated detachments of the retinal pigment epithelium and neurosensory retina. Such a clinical presentation has been termed paraneoplastic vitelliform retinopathy. We describe an 80-year-old man with metastatic cutaneous melanoma who developed paraneoplastic vitelliform retinopathy. For the first time, histopathology from enucleation specimens provides a clinicopathologic disease correlation with focal abnormalities in the inner nuclear and outer plexiform layers.

Acute exudative paraneoplastic polymorphous vitelliform maculopathy in five cases

BACKGROUND AND OBJECTIVE

To evaluate clinical features, course, and outcome of patients with acute exudative paraneoplastic polymorphous vitelliform maculopathy (AEPPVM).

PATIENTS AND METHODS

Retrospective case series of 5 patients.

RESULTS

There were 3 males and 2 females, with a median age of 74 years. The primary neoplasms were cutaneous melanoma (n = 2), choroidal melanoma (n = 1), lung adenocarcinoma (n = 1), and lung plus breast adenocarcinoma (n = 1). The mean interval between the diagnosis of the primary neoplasm and the diagnosis of AEPPVM was 42 months. The presenting symptom was blurred vision in all cases. Ophthalmoscopy disclosed multifocal localized shallow serous detachments of the post-equatorial neurosensory retina with yellow-white subretinal debris confirmed by optical coherence tomography (OCT). There was a mean of 21 individual sites of detachment per eye, each measuring a mean of approximately 0.8 millimeter in diameter. Fundus autofluorescence depicted hyperautofluorescence corresponding to the detachments. After mean follow-up of 5 months, three patients had died of metastases. Of the two survivors, one showed resolution of lesions and the other was unchanged.

CONCLUSION

AEPPVM is a paraneoplastic retinopathy found in patients with metastatic melanoma or carcinoma. The most salient feature is reduced visual acuity from multifocal shallow retinal detachments less than 1-mm diameter, best depicted on OCT.

Optical coherence tomography findings in paraneoplastic pseudovitelliform lesions in melanoma-associated retinopathy

Purpose

To report an unusual case of paraneoplastic pseudovitelliform lesions associated with melanoma-associated retinopathy (MAR).

Design

Observational case report.

Methods

Retrospective review of the ophthalmic examination, fundus photography, fluorescein angiography, electroretinogram (ERG), and optical coherence tomography (OCT) of a patient with MAR.

Results

A 65-year-old Caucasian man with a two-year history of metastatic melanoma was referred for evaluation of a six-month history of nyctalopia. Funduscopic examination in both eyes revealed multiple, creamy, yellow, pseudovitelliform lesions in the posterior pole, varying in size from 100–500 μm, at the level of the outer retinal/retinal pigment epithelium (RPE) junction, coalescing along the inferior portion, with overlying macular neurosensory detachments. OCT showed bilateral macular neurosensory detachments with multiple small areas of high reflectivity at the level of the outer retinal/RPE junction. ERG demonstrated a selective loss of the b-wave and a normal a-wave under dark adapted, scotopic conditions.

Conclusion

Clinicians should be aware of this atypical presentation of MAR that may include pseudovitelliform retinal findings.

Paraneoplastic vitelliform retinopathy in metastatic cutaneous melanoma

PURPOSE

To report the clinical picture and investigative findings of unusual paraneoplastic retinopathy lesions in a patient with metastatic skin melanoma.

METHODS

A middle-aged man presented with mild blurring of vision in one eye. He had metastatic skin melanoma to the axillary lymph nodes, which was treated by interferon. Fundus photographs showed bilateral unusual multiple vitelliform lesions. Retinal and serologic investigations were performed.

RESULTS

These vitelliform lesions involved the outer retinal layers and retinal pigment epithelium (RPE) as demonstrated by optical coherence tomography and have completely blocked choroidal fluorescence without late staining in angiography. There was only minimal reduction of Arden ratio in electro-oculography, although electroretinography was essentially normal. Antibipolar cells autoantibodies were not detected in this case.

CONCLUSION

This melanoma-related paraneoplastic retinopathy may represent a separate entity from the classic findings in melanoma-associated retinopathy (MAR) syndrome. Optical coherence tomography is helpful to differentiate it from simulating lesions. Recognition of this presentation can help to diagnose the presence of an occult metastaticmelanoma in some cases.

Vitiligo and melanoma-associated hypopigmentation (MAH): shared and discriminative features

BACKGROUND

It is unclear if differences between melanoma-associated hypopigmentation (MAH) and classical vitiligo exist.

PATIENTS AND METHODS

Hypopigmented areas and associated lesions (halo nevi, hypopigmented scars) in 15 melanoma patients and 31 patients with classical vitiligo were analyzed by digital photography. The activity of the respective lesions was assessed by the vitiligo disease activity (VIDA) score. Associated diseases were recorded by history and serological tests;genotyping of HLA class I antigens as well as histology/immunohistology were performed.

RESULTS

MAH were diagnosed in 12 of 15 melanoma patients; mean onset was 4.8 years after the primary diagnosis of the melanoma. Three melanoma patients reported hypopigmentation more than 15 years before diagnosis of melanoma. In the history and family history of vitiligo patients, autoimmune diseases were much more frequent and haplotype HLA-A2 was twice as common compared to MAH patients. MAH lesions were most often distributed in a bilateral symmetrical pattern, corresponding to vitiligo. MAH was less progressive compared to classical vitiligo; however, it was more often associated with other acquired leukodermas. In both groups hypopigmentation spread centripetally to the trunk. Histological and immunohistological differences were not found.

CONCLUSIONS

Whereas differences exist concerning associated autoimmune diseases, MAH and vitiligo shared many common clinical and histological features. Further studies are needed to assess the clinical relevance of vitiligo-like alterations in melanoma patients.

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.

Paraneoplastic syndromes in patients with primary head and neck cancer

Paraneoplastic syndromes represent the clinical manifestations of the indirect and remote effects produced by tumor metabolites or other products. The clinical spectrum of the various paraneoplastic syndromes related to primary malignancies of the head and neck region is presented. A review of the literature on paraneoplastic syndromes in patients with primary head and neck cancer was carried out. Paraneoplastic syndromes related to primary malignancies of the head and neck region can be categorized as: endocrine, cutaneous or dermatologic, hematologic, neurologic, osteoarticular or rheumatologic, ocular syndromes. Sometimes, paraneoplastic syndromes can be more serious than the consequences of the primary tumor itself and can precede, follow or be concurrent to the diagnosis of a malignancy; moreover, they can dominate the clinical picture and thus lead to errors with respect to the origin and type of the primary tumor. Physicians who deal with cancer-associated syndromes should be able to differentiate the paraneoplastic syndromes from the benign disorders that mimic them. Patients with a suspected paraneoplastic disorder should undergo a complete panel of laboratory studies, in addition to imaging studies and endoscopy. Identification of paraneoplastic syndromes allow the clinician to make an early diagnosis and to provide adequate treatment of tumors, with a favorable oncologic outcome and improved life expectancy for the patient. These syndromes can follow the clinical course of the tumor and thus be useful for monitoring its evolution.

Recoverin as a cancer-retina antigen

In photoreceptor cells the Ca(2+) -binding protein recoverin controls phosphorylation of the visual receptor rhodopsin by inhibiting rhodopsin kinase (GRK-1). It can also serve as a paraneoplastic antigen in the development of retinal degeneration in some patients with cancer. The aberrant expression of recoverin in cancer cells and the presence of autoantibodies against recoverin are essential for the occurrence of cancer-associated retinopathy, which finally results in the apoptosis of photoreceptor cells. Noteworthy in cancer patients, the aberrant recoverin expression and the appearance of autoantibodies against recoverin are more frequent than paraneoplastic syndromes. We suggest the term "cancer-retina antigens" for this kind of proteins like recoverin that are solely expressed in retina and tumor tissues and evoke antibodies and/or T cells in patients with cancer. The rare development of a paraneoplastic syndrome is possibly caused by this immune response and probably depends on further events allowing to overcome the blood-retina barrier and the immune privileged status of the retina. It is still unknown whether aberrantly expressed recoverin could have a specific function in cancer cells, though it is suggested that it can be functionally associated with G-protein-coupled receptor kinases. This paper reviews the present knowledge on paraneoplastic syndromes associated with the aberrant expression of recoverin. A possible application of recoverin as a potential target for immunotherapy of cancer is discussed.

Vitiligo as a paraneoplastic syndrome preceding pituitary adenoma and subsequent acute lymphoblastic leukemia

We present an unusual case of rapid onset of vitiligo heralding blindness due to pituitary apoplexy secondary to a non-secreting pituitary adenoma in a 49-year-old man. Deterioration in vision and skin condition coincided with tumor progression over 3 years. He subsequently died of acute lymphoblastic leukemia after pituitary radiation. The possible pathological associations between the 2 malignancies and vitiligo are discussed.

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.

Ocular melanoma

This article reviews the current pathogenesis, molecular changes, diagnosis, and treatment of ocular melanomas. Ocular melanomas can involve the eyelid, conjunctiva, intraocular structures, and the orbit. The most common eye melanoma involves the uveal tract and is responsible for approximately 13% of melanoma deaths. Uveal melanomas account for 10% of all melanomas.

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.