- Eye Health
|Welcome to the second edition of IMAGE for 2011. This issue we review melanocytoma (magnocellular naevus) and share how one of our most regular referrers, Hanna Kim from Strathfield, has integrated CFEH services into her own practice.|
Over the past 18 months CFEH has proudly delivered free advanced imaging and early detection services for people in NSW and the ACT. In most cases, our patients are initially screened by their optometrist and deemed to be at-risk or suspected of having an early-stage eye disease. In some instances we also work with optometrists or ophthalmologists to monitor known conditions.
|This partnership approach has been wholeheartedly embraced by our top referrers, who are leading the way in advancing the profession of optometry.|
With the introduction of mandatory CPD last year, we have already noticed improvements with more optometrists using routine eye examinations to identify at-risk patients, refining differential diagnoses, or starting to co-manage known eye diseases in conjunction with other specialists.
Striving to become a Centre of Excellence in service delivery is about more than acquiring the latest and greatest technology instruments, or hiring the best and brightest clinicians. It is also about forging symbiotic relationships to achieve mutually beneficial outcomes for our community. The blending of the ophthalmic, academic and not-for-profit community sectors at CFEH is what makes this service so unique and valuable.
Prof. Michael Kalloniatis
Black masses on the optic nerve head and retinal periphery
|Genevieve, a 28-year-old female, presented to her optometrist for a general eye examination to correct myopia. Her optometrist noted a small dark lesion on the left optic nerve and pigmentation in the temporal periphery of the right eye. She had LASIK four years earlier.|
Issues to consider
1. What imaging can provide the optometrist with more information about the lesion?
2. Is visual function affected?
3. Are the black masses in the two eyes somehow related?
Figure 1A: Optomap image of the pigmented lesions in the right eye (circled).
Figure 1B: Red-separation image of pigmented lesions in the right eye (circled).
Genevieve was referred to CFEH for further investigation of pigmented lesions in both eyes. With the exception of LAS IK she had no significant ocular history, nor a family history of eye disease. Visual acuity was 6/7.5 in both eyes.
Documentation of the pigmented areas, to assess morphological characteristics and any potential visual dysfunction, took place at CFEH. Tests included posterior pole photography, wide-field fundus photography (Optomap), an evaluation of the optic nerve heads using Optical Coherent Tomography (OCT), Heidelberg Retina Tomography (HRT3) and visual field assessment using the Matrix perimeter.
The two very small pigmented lesions in the right temporal retina were approximately 10 disc diameters from the optic nerve head without any associated changes (Figure 1A). The dark image, obtained with red separation imaging (Figure 1B), confirmed that it is ocular pigment, located in the choroid.
Optic nerve cup/disc ratio was approximately 0.4 with peripapillary atrophy in both eyes. The left optic nerve had a small black mass on the superior aspect of the disc with indistinct edges (fluffy appearance) at the nerve fibre layer (Figure 2B).
Cirrus OCT imaging through the left optic nerve lesion showed a collection of hyper-reflective material with posterior shadowing (Figure 3). Such a finding is similar to those previously reported by Shields et al2 in their description of optic disc melanocytoma. Retinal nerve fiber layer analysis showed it to be within the normal range in both eyes and the Moorfields Regression Analysis of the HRT3, gave a borderline result for the left eye.
Visual dysfunction suggested by the nerve fiber layer drop-out (Figure 4) was confirmed through a deficit in the inferior arcuate region (Figure 5).
The nerve fibre layer drop-out, and the beginning of an arcuate visual field defect, is not typical of expected changes due to optic nerve melanocytoma (see later). Consultation with a CFEH ophthalmologist resulted in a recommendation that the patient be reviewed by a retinal specialist to fully elucidate the reason for the visual field loss and confirm that the melanocytoma was benign.
The very small pigmented lesions in the right eye may reflect choroidal melanocytomas, but this cannot be confirmed with imaging alone.
The two lesions are small and any change can be tracked through photo-documentation.
Melanocytoma (magnocellular naevus) is a rare condition that can be localised on the optic nerve head, choroid, iris, ciliary body, and diffusely localised in the uvea (also referred to as ocular melanocytosis)(1,2) or on the conjunctiva and sclera(3).
Melanocytomas on the optic nerve are comprised of melanocytes and myelin, and are normally benign. They arise from dendritic uveal melanocytes in the lamina cribrosa of the optic nerve head and can extend into the retinal nerve fibre layer. They rarely produce symptoms, but if large, may produce a relative pupillary defect or visual field loss (enlarged blind spot).
While usually benign, a few cases of malignancy have been reported in optic nerve melanocytomas (a 2% malignancy rate has been reported)(4), so cautious management is required. This would include a stereoscopic view to detect any subretinal fluid, detailed photography in order to monitor any changes over time, and a visual field test to determine if it has any effect on vision, in addition to providing accurate measurements in order to detect any progression. OCT is also useful to further characterise optic disc melanocytomas.
Shields et al(5) reported that optic disc melanocytomas have a gradually sloped nodular elevation with a hyper-reflective anterior surface and abrupt, dense posterior shadowing portraying an optically empty mass. Due to the hyper-reflective nature of this tumour, internal characteristics are not possible using OCT. If this is the first time it has been observed, a short follow-up time of 3-6 months may be warranted, tapering as the stability of the mass is confirmed to clinical photography once a year. If there is any suspicion of malignancy, referral to an ophthalmological oncologist is required.
Melanocytomas in the optic nerve or elsewhere in the uveal track can undergo necrosis with associated ischaemic optic neuropathy, secondary glaucoma and associated vision loss(4). Gonioscopy, intraocular pressure tracking and baseline visual fields are essential.
Malignant melanoma, invading the optic nerve head, may be primary or metastatic and should be considered in the differential diagnosis. It typically has a more varied presentation, with patches of more lightly pigmented areas. It tends to distort blood vessels, and in aggressive cases feeder vessels may be visible. There may be surface deposits. It can cause retinal or disc oedema, haemorrhages, and retinal detachment as it increases in size. This has to rank highly in the differential list, as it is important to rule it out due to its potential high morbidity and mortality(1). Other, less likely conditions that may be included as differentials include; reactive retinal pigmented epithelium hyperplasia or retinal pigmented epithelium adenoma and choroiditis.
Choroidal melanocytomas are thought to be dormant lesions that remain stable although subretinal fluid and visual field defects have been reported(2). Clinically, these lesions have identical features to other choroidal naevi or small melanomas with histological results required for differentiation(2).
This edition prepared by Michael Kalloniatis, Centre Director, and Agnes Choi, Staff Optometrist.
Names and details of patients have been changed to protect privacy.
Hanna Kim runs a busy optometry practice in the centre of Strathfield, and has already referred more than 100 patients for advanced imaging at CFEH.
“I keep pinching myself” says Hanna. “Having access to CFEH really helps my practice. My patients have such a positive experience when going there, they are so thankful, and are just wowed by all of the equipment.”
Hanna’s approach to integrating CFEH services as a part of her own practice is a good example of how to make the partnership model work.
“I set up six years ago, and at first had minimal equipment. I was worried about keeping up with the technology, but wanted to provide these tests to my patients. Now, with CFEH, it’s kind of like having it all here. Not right in my practice, but near enough!
“One of the things I value most is the free translation service. Many of my patients come from Korean backgrounds and do not speak English. I often have to find Korean speaking eye doctors for them. My patients are often quite hesitant about going, especially if it’s not even certain that there is a problem, and want to take a family member with them. When I tell them that we can get an interpreter for them, and the tests are completely free, they are so relieved and happy.
“I initially hesitated because I thought that Kensington was a bit of a trek, but honestly my patients are very happy to travel when they know it means accessing the best at no cost.”
Carol, a 60-year-old female with a nine year history of Type 2 diabetes, was referred to CFEH and diagnosed with mild to moderate non-proliferative diabetic retinopathy. At the four month follow-up with her optometrist, Carol said that her blood glucose control had deteriorated due to stress. During a dilated eye examination, her optometrist noticed an increased number of intraretinal haemorrhages and a small decrease in best corrected visual acuity to 6/7.6 in each eye. As a result, Carol was referred back to CFEH for further evaluation.
Disclaimer: This newsletter is not intended to provide or substitute advice through the appropriate health service providers. Although every care is taken by CFEH to ensure that this newsletter is free from any error or inaccuracy, CFEH does not make any representation or warranty regarding the currency, accuracy or completeness of this newsletter.
Copyright: © 2011, Centre for Eye Health Limited. All images and content in this letter are the property of Centre for Eye Health Limited and cannot be reproduced without prior written permission of the Director, Centre for Eye Health Limited.