Macular conditions. by Louise Stainer BSc(Hons)

Size: px

Start display at page:

Download "Macular conditions. by Louise Stainer BSc(Hons)"

Delilah Cole
5 years ago
Views:

4 dispensingoptics December 2013 Macular conditions by Louise Stainer BSc(Hons) CompetencIes covered: Dispensing opticians: Ocular Examination, Ocular Abnormalities, Low Vision Optometrists: Ocular

conditions. This article discusses some of these disorders in more detail. Macular hole A macular hole most commonly presents in women in their fifties.

1 4 dispensingoptics December 2013 Macular conditions by Louise Stainer BSc(Hons) CompetencIes covered: Dispensing opticians: Ocular Examination, Ocular Abnormalities, Low Vision Optometrists: Ocular Disease A variety of macular conditions may be encountered in our patients whilst performing eye examinations or individuals may attend high-street practice with symptoms or questions about these conditions. This article discusses some of these disorders in more detail. Macular hole A macular hole most commonly presents in women in their fifties. One theory of macular hole development is based on vitreous traction. The vitreous gel in the centre of the eyeball is attached to the retina at various points including blood vessels, the macula and the optic disc. Changes in the vitreous structure occur with aging. These include liquefaction and shrinkage and may result in vitreous traction involving the various retinal connections. If these connections all detach a full posterior vitreous detachment (PVD) results and a Weiss ring may be visible in the vitreous during slit lamp examination. If the macular attachment remains, continued vitreomacular traction can initially result in cystic changes in intraretinal layers and/or a foveal detachment. There is a high chance of selfresolution if a full PVD occurs during these early stages. Otherwise continued macular traction can cause progression until more retinal layers are involved culminating in the rupture of the retinal roof of the cyst. This may be visible on an OCT scan (Figures 1a and 1b). This leads to the formation of a small full thickness a b Figure 1a and 1b: OCT scans showing macular hole formation 1 This article has been approved for 1 CET point by the GOC. It is open to all FBDO members, including associate member optometrists. The multiple-choice questions (MCQs) for this month's CET are available on page 9 and online. Insert your answers to the six MCQs on the inserted sheet or online at After log-in, go to 'CET Online'. Please ensure that your address and GOC number are up-to-date. The pass mark is 60 per cent. The answers will appear in the February 2014 issue of Dispensing Optics. The closing date is 16 January C-34270

Continuing Education and Training Figure 2: Full thickness macular hole with cystic changes 1 Figure 3: Opaque epiretinal membrane 1 macular hole (FTMH) that then increases in size if traction

The patient may be given an Amsler chart and advised to carry out monocular monitoring regularly.

2 Continuing Education and Training Figure 2: Full thickness macular hole with cystic changes 1 Figure 3: Opaque epiretinal membrane 1 macular hole (FTMH) that then increases in size if traction continues. At the early stages of macular hole development the patient may be unaware of any symptoms particularly if the other eye is normal. The patient may be given an Amsler chart and advised to carry out monocular monitoring regularly. They should return for re-evaluation if any symptoms, such as distortion of the grid or a drop in visual acuity develop or worsen. They should also check each eye as there is also a risk of macular hole development in the other eye. This has been found to occur within five years in between 10 and 20% of patients with a FTMH in the other eye although this figure reduces dramatically to under 1% if a full PVD has already occurred 2. As the macular hole develops individuals may also experience micropsia (the perceived image appears smaller than in reality). Distortion is often of a pincushion type in that the middle of the image appears larger than the edges. This is caused by retinal disruption with the outward displacement of foveal photoreceptors during hole development. Individuals with a macular hole may not be able to see the centre of people s faces making recognition of others difficult. Retinal changes are usually visible on a macular scan performed using Ocular Coherence Tomography (OCT). OCT is a non-invasive diagnostic tool that can produce cross-sectional images of various parts of the eye including the retina based on the varying reflectance properties of different tissue layers. If this is not available slit lamp examination with a 90D Volk lens reveals an unusual macular reflex. Use of a red-free filter may highlight cystic changes. A full thickness macular hole has the appearance of a single red lesion usually with well-demarcated edges. Its edges may be made up of a grey cuff of retinal detachment (Figure 2 1 ). The Watzke-Allen slit beam test may also be a useful tool in the diagnosis of macular hole. During slit lamp examination of the fundus with a Volk lens a narrow slit beam of light is briefly placed at the fovea. The patient is asked if the rectangular light looks regular or if there are any parts missing. If the fovea is intact the beam will appear normal but if a full thickness macular hole is present the beam will seem distorted (narrowing or bending) or there may be a gap present in the centre 2. The beam will be also be perceived as normal in individuals with a pseudohole as changes correspond to the absence of retinal tissue 3. Treatment involves a vitrectomy (removal of the vitreous gel) to relieve macular traction and insertion of a heavy gas or oil to provide a temporary seal to enable and promote healing. The likelihood of cataract development following this type of surgery is high (seen in more than 80% of cases) so it is often performed in combination with phacoemulsification and intraocular lens replacement 4. Pseudohole and epiretinal membrane A pseudohole has a similar appearance to a full thickness macular hole but is not a true hole. It is normally characterised by macular thickening with a steepening of the foveal contour and lack of a full thickness defect. Usually it is formed by the presence of an epiretinal membrane that contracts around the macula. Glial cells migrate through minute breaks on the surface of the retina (internal limiting membrane), proliferate and collectively form a transparent membrane. The epiretinal membrane may continue to progress and become thickened and more opaque in nature. Its contractile activity often results in retinal striae that are best viewed by slit lamp using retro-illumination. Contraction can also cause the retinal blood vessels to appear to be more tortuous and may result in macular oedema. Epiretinal membranes are not always seen in conjunction with a pseudohole (Figure 3). Patients with early stage epiretinal membrane may be asymptomatic particularly if the macular area is not yet affected. Those with a significant epiretinal membrane may experience distortion (metamorphopsia), blurring of their central vision and a reduction in their visual acuity. Less common symptoms include variation in image size (macropsia or micropsia) or monocular diplopia due to disruption of the photoreceptor layer. Surgery is usually only performed if deemed necessary such as individuals with debilitating symptoms. This involves a vitrectomy and membrane peel and is usually performed as a day case under local anaesthetic. Risks associated with this procedure Continued overleaf

6 dispensingoptics December 2013 Figure 4: OCT image of CSR 1 include deterioration in visual quality compared with prior to surgery, subsequent recurrence of the epiretinal membrane and development

3 6 dispensingoptics December 2013 Figure 4: OCT image of CSR 1 include deterioration in visual quality compared with prior to surgery, subsequent recurrence of the epiretinal membrane and development of a retinal detachment. Lamellar hole A lamellar hole is thought to be an early macular hole that did not develop into a full thickness macular hole. It is not certain why this occurs in some people and not others. It also has a similar appearance to a FTMH and a pseudohole so without OCT differential diagnosis may be difficult. However individuals with lamellar holes are likely to have near to normal visual acuity with little or no distortion experienced in contrast to those with FTMHs. Central Serous Retinopathy (CSR) This condition is significantly more common in men and may be triggered by situations of extreme stress. People with Type A personality have been shown to be more at risk. There is also an increased risk of CSR in people who have been prescribed corticosteroid treatments including topical steroids for unrelated conditions 5. Repeated episodes occur in between a third and half of all individuals with CSR 6. Acute CSR is the most common form. This is thought to be due to the leakage of serum from an impaired choroidal blood circulation (choriocapillaris) through dysfunctional tight junctions situated between RPE cells. This results in the separation of the RPE from the photoreceptor outer segments at the macula (localised neurosensory retinal detachment) due to the fluid collecting between the two layers 7 (Figure 4). On slit lamp examination the fovea usually appears elevated with a loss of foveal reflex. The patient may experience metamorphopsia. Symptoms of micropsia may also be confirmed using an Amsler grid This is because fluid accumulation causes separation of foveal photoreceptors and the brain receives fewer signals for a given area 8. These individuals may also notice a reduction in their visual acuity (normally to between 6/9 and 6/12) corresponding to a small hyperopic prescription found using retinoscopy or an autorefractor 9. They may also report previous short-term episodes of blurred vision and be conscious of a defect in their central visual field (central scotoma) 7. Fortunately no treatment is needed in the majority of CSR cases as they selfresolve. This usually occurs over a period of two to three months. Therefore on confirmation of diagnosis the patient is usually monitored for several months without treatment 10. If the sub-retinal fluid remains over a period of more than six months the CSR is defined as chronic and also characterised by various changes to the retinal pigment epithelium. Chronic cases are thought to make up 5% of the total number 6. These individuals may be treated with Argon laser (photo coagulation) to resolve the leakage if it is at a specific location and situated extrafoveally as retinal scarring results 7, 11. If the leakage site is foveal or diffuse in nature a treatment called Photo Dynamic Therapy (PDT) may be considered 5. This reduces choroidal blood flow in the target area, alleviating leakage but can result in the development of new blood vessels that are themselves prone to leakage (choroidal neovascularisarion) 5. Cystoid Macular Oedema (CMO) CMO is linked with numerous conditions such as diabetic retinopathy, central and retinal vein occlusion and ocular inflammation (uveitis). However it most commonly occurs following cataract surgery (usually three to twelve weeks after the original procedure) 12. It is thought that trauma to the iris and lens epithelial cells during surgery causes these tissues to synthesise and release inflammatory mediators including prostaglandins. These are hormone-like compounds that bind to specific receptors culminating in a number of various effects depending on receptor location. After cataract surgery their presence stimulates the proliferation of various inflammatory mediators as well as vascular endothelial growth factor (VEGF) production 13. These chemicals diffuse through the vitreous to the retina and cause the blood retinal barrier (tight junctions between RPE cells and endothelial cells forming retinal capillaries) to become more permeable. Serum leaks from perifoveal capillaries, displacing retinal cells to form fluid filled cysts situated between the inner nuclear and outer plexiform retinal layers 13. As the condition progresses the cysts increase in size and coalesce across the retinal layers. Occasionally this may result in the development of a lamellar macular hole if there is breakdown of the inner retinal wall of the cystic space 14. Individuals with CMO often experience blurred vision and distortion (metamorphopsia) although they may be asymptomatic. Fortunately CMO resolves in over 90% of cases that develop following phacoemulsification 15. However leakage persists in a small number of patients and may have a significant and irreversible impact on their visual acuity if not treated successfully 15. There are several possible treatment options for CMO. Non-steroidal antiflammatories (N-SAIDs) inhibit enzymes involved in prostaglandin production and are more effective against CMO when prescribed in combination with a corticosteroid 16,17. Corticosteroids have various effects including normalising the permeability of the blood retinal barrier and Continued overleaf

4 8 dispensingoptics December 2013 preventing the synthesis of inflammatory mediators. Topical eyedrops may be the first option but if required a higher dose may be administered by subtenon injection (into the space between the eyeball and orbital fat). More severe cases of CMO may be treated with an intravitreal injection of triamcinolone acetate (kenalog), a synthetic corticosteroid. This achieves drug delivery directly to the required site but is a more invasive method. It has an increased risk of complications such as intraocular pressure elevation postoperatively. Less common postoperative complications include retinal detachment and endophthalmitis 17. Myopic maculopathy High myopia is defined as shortsightedness with a spherical equivalent of over 6 dioptres or an eyeball with an axial length of greater than 26.5mm 18. In pathological myopia various degenerative changes are also present. This condition is becoming more common particularly in Asian populations and is a significant cause of blindness globally. The exact pathogenesis is unknown but genetic and environmental factors have been shown to play a role 19. Myopic maculopathy is characterised by a number of clinical signs that may include lacquer cracks, posterior staphyloma, choroidal neovascularisation (CNV) and geographic atrophy 18. Lacquer cracks are breaks in Bruch s membrane, the layer situated between the choroid and the retinal pigment epithelium (RPE). One theory is that retinal stretching results in the release of vascular endothelial growth factor (VEGF) which binds to specific receptors on blood vessel walls, stimulating the development of abnormal new vessels from choroidal blood vessels (neovascularisation) 20. It only occurs in a small number of patients with pathological myopia. However pathological myopia is still the most common cause of CNV in individuals under 50 years of age (causing 62% of CNV in this age group) 21, 22. This type of CNV can undergo spontaneous regression or remain stable without treatment. However development and chorioretinal atrophy zone expansion at CNV borders during the chronic phase of the condition causes a progressive decline in the patient s vision. Treatment of the CNV prior to the development of atrophy has been shown to sustain or even improve the patient s initial level of visual acuity 21. Currently PDT is the only procedure authorized by the National Institute of Clinical Excellence (NICE) for the treatment of CNV associated with pathological myopia. Clinical trials of anti-vegf therapies administered by intravitreal injection are currently in progress. These drugs bind to and block VEGF receptors, inhibiting its action. One of these compounds Lucentis (ranibizumab) has recently been approved by the European Commission for use in the treatment of this condition in the European Union 23. This article has illustrated that there are numerous macular conditions that look similar in appearance. The availability of OCT in certain high street practices can make detection, differential diagnosis and management of such diseases easier. References 1. Chen J. Personal communication. ( 2. Sharkey JA, Williams MA. Macular Holes: A treatable Cause of Central Visual Deterioration. Optometry in Practice [online]. (2006); 7: Available at practice.org/filemanager/root/site_ass ets/7-4/macular_holes_a_treatable_ cause_of_central_visual_deterioration- 1_ _1.pdf. 3. Khandhadia S, Newsom R. Diagnosis and Management of red fundus lesions. Optician. 2008; Available at net/assets/getasset.aspx?itemid=3153. (accessed 21 October 2013) 4. Yuan A. Update on Surgery For Macular Hole and Pucker. New advances and continuing controversies. Retinal Physician [online] Available from physician.com/articleviewer.aspx?artic leid= September 2013) 5. Colucciello M. Central Serous Retinopathy [online] Available from com/articleviewer.aspx?articleid= (accessed on Liew G, Quin G, Gillies M and Fraser-Bell S. Central Serous Retinopathy: a review of epidemiology and pathophysiology. Clinical & Experimental Opthalmology. 2013; 41: Garg A. Chapter 39. Central Serous Retinopathy. In: Garg A, Alio JL. Surgical Techniques of Ophthalmology. Retina and Vitreous Surgery. 1 st Ed. Jaypee Highlights Medical Publishers 2010; p O Toole L. Management of Retinal Conditions. Optometry Today [online] 2010: Available from articles/cet% _1.pdf. (accessed Dabasia P. Assessment of macular function in practice. Optician [online] 2005: Available from getasset.aspx?itemid=1196. (accessed 4 October 2013) 10. Benson M. Distortion from exams/articles/cet_25_nov_2011_bens on.pdf. (accessed Colucciello M. Update on Central Serous Chorioretinopathy. Among other findings, reduce-fluence and lost-dose PDT look promising. Retinal Physician [online] Available from eviewer.aspx?articleid= (accessed 19 October 2013) 12. Rotsos TG, Moschos MM. Cystoid Macular Oedema. Clin Ophthalmol. 2008; 2(4): Wielders LHP, Schouten JSAG, Van Den Biggelaar FJHM, Winkens B, Nuijts RMMA. Prevention of CMO after Cataract Surgery. Investigators of the ESCRS PREMED study hope to establish evidence-based clinical guidelines [online] Available from /08/article.asp?f=prevention-ofcme-after-cataract-surgery. (accessed Walker N, Pal B. Macular Oedema, Aetiology, differential diagnosis and management. Optician [online] 2011: Available from opticianonline.net/assets/getasset.asp x?itemid=5732. (accessed Lobo C. Pathogenesis of Cystoid Macular Oedema. European Ophthalmic Review. Touch Briefings 2012; Singer MA. Management of

5 Continuing Education and Training Cystoid Macula Oedema. Refractive Eyecare [online] Available from 12/10/management-of-cystoidmacular-edema/. 17. Ober MD, Klias CM, Cunningham ET. Management Options for Macular Oedema. Many strategies have been used to manage macular oedema, with varying degrees of success [online] Available from etinal_insider/i/1310/c/25220/. (accessed Chen S-J, Cheng C-Yu, Li A-F, Peng K-L, Chou P, Chiou S-H, Hsu W-M. Prevalence and Associated Risk Factors of Myopic Maculopathy in Elderly Chinese: The Shihpai Eye Study. Investigative Ophthalmology and Visual Science [online]. 2012; 53(8): Available from 8.long. 19. Mitry D, Zambarakji H. Recent trends in the management of maculopathy secondary to pathological myopia. Graefes Arch Clin Exp Opthalmol. 2012; 250: Silva R. Myopic maculopathy: A Review. Ophthalmologica 2012;228: Ohno-Matsui K. Global perspectives: Advances in Diagnosis and Treatment of Pathologic Myopia. OCT imaging and novel therapies have improved outcomes in eyes with myopic CNV and myopic macular retinoschisis. Retina Today [online] Available from net/retinatoday/2011/08/article.asp?f= global-perspectives-advances-indiagnosis-and-treatment-ofpathologic-myopia. 22. Ikuno Y. Global perspectives: Choroidal Neovascularization Due to Pathologic Myopia. The pathogenesis of this condition is unknown, but anti- VEGF treatment has shown promising therapeutic results. Retina Today [online] Available from /09/article.asp?f=global-perspectiveschoroidal-neovascularization-due-topathologic-myopia media-releases/en/2013/ shtml Louise Stainer is a hospital optometrist at Optegra Eye Hospital, Birmingham. She is involved in the pre and postoperative care of cataract and refractive surgery patients and assists in the macular, glaucoma and retinal clinics. She has previously lectured on the ocular component of the Guide dogs for the Blind guide dog mobility instructors (GDMI) Bachelors and Masters degree courses. Louise has also worked in the Paediatrics department at Kidderminister Hospital, in private practice and has written numerous articles for various optometric and dispensing optician journals. n Multiple choice questions (MCQs): Macular conditions 1. Which statement is not true? a. Treatment for CMO can include non-steroidal antiinflammatories b. 90% of CMOs require treatment c. CMO most commonly occurs following cataract surgery d. CMO occurs as a result of a leakage of serum from perifoveal capillaries 2. Patients with macular changes most commonly experience... a. Distortion when viewing an Amsler grid b. Halos around light sources c. Contracted visual field d. Photophobia 3. Which is not a possible treatment pathway for CSR? a. Regular monitoring for 3 months or longer b. Intravitreal corticosteroid injections c. Photo-coagulation with argon laser d. Photo Dynamic Therapy 4. What is not a clinical sign of myopic maculopathy? a. Choroidal neovascularisation b. Lacquer cracks in Bruchs membrane c. Raised intraocular pressure d. Atrophy at the macular region 5. Which statement is incorrect? a. Macular holes are thought to develop as a result of vitreous changes and traction with the retina b. Macular holes are more prevalent in males over 50 years old c. Treatment of macular holes can involve vitrectomy d. Within five years 10-20% of patients with a full thickness macular hole will develop a macular hole in the other eye 6. Which statement is true? a. Epiretinal membranes occur as a result of ocular trauma b. A migration and proliferation of glial cells give rise to an epiretinal membrane c. All epiretinal membranes require surgical removal d. Contraction of the epiretinal membrane usually causes retinal haemorrhage The deadline for posted or faxed response is 16 January The module code is C Online completion after member log-in go to CET online After the closing date, the answers can be viewed on the 'CET Online' page of To download, print or save your results letter, go to 'View your CET record'. If you would prefer to receive a posted results letter, contact the CET Office or cet@abdocet.infoman.org.uk Occasionally, printing errors are spotted after the journal has gone to print. Notifications can be viewed at on the CET Online page

EPIRETINAL MEMBRANE & VITREOMACULAR TRACTION

EPIRETINAL MEMBRANE & VITREOMACULAR TRACTION Management of ERM and VMT K.V.Chalam,MD,PhD,MBA,FACS Professor and Director of Retina Loma Linda Eye Institute Los Angeles, USA REVIEW ANATOMY The vitreous