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Home , Epiretinal membrane, Myopia, Retinal haemorrhage

mivision • ISSUE 130 • DEC 17 miophthalmology 35 THE

The Myopic : ISSUE Taming the Beast

WRITER Dr. Abhishek Sharma and Dr. Christolyn Raj

“People live in different sized houses, from small cottages to spacious mansions. But imagine if we all received the same Dr. Abhishek Sharma amount of wallpaper to line the walls of “Myopic have a our home. Those living in larger houses would need to stretch out their wallpaper, higher risk of retinal making it very thin to ensure it fits their walls. That wallpaper will be weaker, be complications, such prone to tearing, may not 'stick' to the wall as well and will have a tendency to as curl over or tear in its weakest areas. As a myopic person, you could imagine your as a mansion, and the wallpaper when compared with as the retina.” emmetropic eyes” As retinal specialists, we frequently use this explanation to begin the discussion about the many retinal issues a patient with myopia needs to be aware of and how we may manage their associated risks. anatomy of the eye. In this article, we will Dr. Christolyn Raj briefly look at some of our knowledge on Generation X and are the the myopic retina. group with the highest prevalence of The risks of complications myopia. Once suspected to be a ‘looming MYOPIC epidemic’, this ocular condition is now a Myopic maculopathy is becoming the associated with myopia real threat that exists only too commonly, leading cause of irreversible visual 1,2 particularly in many Asian countries. impairment in some Asian populations. increase with age, making In the , it is the fourth Unfortunately, the retinal complications commonest cause of severe visual co-ordinated care of of myopia are the most vision threatening. impairment, ahead of !3 In Ireland Optometrists are in the perfect position and Israel it is already the third leading myopic patients essential to examine these patients, perform the cause of blindness in the working age necessary investigations and refer those population.4,5 Myopic macular changes to prevent loss of sight. ‘at risk’ in a timely manner to a include myopic foveoschisis; myopic retinal specialist. macular holes, with or without localised This co-ordinated care is paramount to retinal detachment; posterior , achieving successful outcomes in the and myopic . The management of myopia, particularly as this extent of the pathology can often be myopic generation ages and their risk of difficult to assess due to the tessellated and complications increases with age. atrophic myopic , and regular ocular coherence tomography (OCT) hold the key The main retinal issues that high myopes to check for progression. face as they age include: MYOPIC FOVEOSCHISIS • Macular pathology AND MACULAR HOLE Foveoschisis involves a split in multiple • Peripheral retinal pathology retinal layers, often with a ‘bridge’ •  and refractive surgical between the layers, giving a characteristic considerations appearance on OCT. Often these patients notice distortion or loss of central vision, •  and the challenges in but many retain surprisingly good vision monitoring progression in a myopic eye even if the macula looks horrendous There is ongoing research into the on OCT. Over time though, their vision mechanisms by which the above problems gradually deteriorates. A long-term study occur, including the link to increased axial found that over a three-year period, lengths, choroidal and retinal thinning. approximately 66 per cent of these patients We have yet to figure out how our will have a significant decline in their treatment methods for myopia, such as vision, and 33 per cent will develop an or , will affect the associated macular hole.6 36 miophthalmology mivision • ISSUE 130 • DEC 17

Figure 1 MYOPIA ISSUE THE

The image demonstrates a myopic suggesting a macular hole are noted to choroidal, Bruch’s membrane (lacquer foveoschisis in a thirty-five-year-old female, clinically, or more likely on OCT imaging. cracks) and RPE layer thinning, splitting who still maintained of 6/9! and rupture. The significance of structural MYOPIC MACULAR DEGENERATION Through experience, most retinal surgeons changes in the development of macular Myopic macular degeneration is a avoid a membrane peel on these degeneration is still being studied. Age progressive disorder in pathologic myopia is a significant contributor to these patients unless there is a demonstrated associated with chorioretinal atrophic biomechanical factors, for example, a decline in central vision. If this occurs, changes and myopic choroidal neo- posterior staphyloma is rarely seen in high surgical intervention is strongly considered vascularisation membranes (CNVMs). myopes younger than age 40.9 as the visual outcome is much more We know high myopia has a familial favourable at this stage before a macular link and thus far, several genes have been Myopic CNVMs occurs in approximately hole develops. However, we make sure the identified in the pathogenesis. However, 10 per cent of high myopes and 30 per cent patient understands that while it is possible their overall influence on the development of the patients who have CNVM in one eye to achieve excellent anatomical closure of macular degeneration is unknown. will develop CNVM in their fellow eye.10 through surgery, the visual outcome will be Along with genetic factors, other factors This alarming incidence rate re-iterates affected by post-operative swelling. It may include the long axial lengths and the need for careful surveillance of myopic take months for swelling to resolve fully, and posterior . These contribute patients who have had a previous CNVM. the re-apposition of the fragile underlying photoreceptors and Muller cell processes will ultimately dictate their final vision. Figure 2 Macular holes can develop in conjunction with foveoschisis or separately. Once a hole has formed in a myopic fundus, there is an increased risk of progression to a macular- hole detachment, where vitreous fluid gradually creeps into the subretinal space at the site of macular hole. The poorly functioning retinal cells, the foveoschisis, and often the presence of a posterior staphyloma, all complicate the final visual outcome. These cases make for challenging , and again it’s common for subretinal fluid to take months to resolve completely. Myopic macular holes without schisis have a high closure rate similar to non-myopic holes, approaching 90 per cent, however for those with significant schisis or macular hole detachment, the closure rate is approximately 50 per cent.7,8 These statistics highlight the need for early referral of these patients if subtle changes mivision • ISSUE 130 • DEC 17 miophthalmology 37 THE

This is perhaps best done clinically with Figure 3 ISSUE MYOPIA a high magnification to examine the macula for sub- and regular follow-up with OCT imaging, looking particularly for subtle subretinal fluid. Should there be any doubt, even in the absence of macular pathology, an urgent referral to a retinal specialist should be considered. Such patients may often have foveoschisis and may require a fluorescein angiogram to ensure there is no active CNVM present.

“Following recovery from retinal detachment surgery, a patient gets to myopic patient is susceptible to inherent with rhegmatogenous retinal detachment know their optometrist weakness from peripheral stretching. following a PVD were myopic. It is important to closely monitor any patient Peripheral retinal degeneration is not with symptoms and clinical signs of a PVD well, as they make uncommon even in non-myopic eyes. as the risk of a tear secondary to PVD is These may include: lattice and snailtrack adjustments to maximise degeneration (figure 2); white without highest in the first few months following pressure (WWP); RPE pigmentary changes PVD. In those patients with an intact their vision” (Pavingstone, cobblestone); as well as vitreous, cautious follow-up is still essential retinal tears. A greater frequency of lattice since the incidence of PVD in patients with retinal degeneration is found when the high myopia increases with age. axial length is 25-27mm and 29-30mm, The primary goal in treating peripheral which corresponds respectively to myopia retinal breaks in a myopic fundus is to Untreated, these CNVMs gradually between 3-10 D. The relationship between prevent progression to retinal detachment progress to scar formation, initially covered the occurrence of peripheral chorioretinal requiring emergency surgery. Retinal by retinal pigment epithelial (RPE) cells to changes also increases with axial myopia. detachment surgery in myopic patients can form a dark pigmented spot (Fuchs spot) and then to chorioretinal atrophy resulting Myopia up to –3 D has been seen to be quite challenging, because the vitreous is in permanent visual loss. While there is no increase the risk of retinal detachment, often still partially attached. Additionally, treatment for chorioretinal atrophy, there while myopia greater than –3 D increases patients are younger in age and therefore is excellent treatment for CNVMs in the the risk of retinal detachment tenfold. phakic with the risk of developing a form of anti-vascular endothelial growth Given these figures, a diligent examination post-operatively. factor (anti-VEGF) injections, similar to of the peripheral fundus in our myopic RETINAL DETACHMENT age-related macular degeneration (AMD) patients could avoid devastating A retinal detachment in a high myope patients. A recent five-year outcome study complications of retinal detachment. provides a few challenges. Often the demonstrated that while the injections The presence of macular changes such as patients tend to be younger, or have work at stopping active CNVMs, myopic a foveal schisis or can undergone recent intraocular surgery CNVM patients require fewer injections signal potential peripheral degeneration and have multiple retinal tears or areas than AMD patients. Similar to AMD such as the existence of a retinal break or of retinal thinning. Once their retina patients, in managing patients with other pathology that may be contributing is detached in one area, it can progress myopic CNVM, there needs to be sound to the macular pucker. There are many quickly in other areas, including the collaboration between optometrists and types of retinal breaks that may be found inferior retina. With their extensive lattice, the retinal specialist. These patients require in the retinal periphery. The common they can quickly form a Giant Retinal Tear, frequent follow-up with OCT imaging in ones include atrophic retinal holes with which involves a tear greater than three- both eyes to monitor the treatment and or without an operculum; atrophic single clock-hours of the retina (figure 3). detect new changes, with timely referral or multiple holes within an area of lattice; A variety of factors decide the surgical minimising delay in treatment.11 or a horseshoe or giant retinal tear. It may steps, including the patient’s age, Patients receiving anti-VEGF injections be reasonable to conservatively manage presence of cataract, location of tears for myopic CNVM should also be advised an atrophic hole or operculated hole in a and detachment, other eye and that they are at higher risk of developing non-myopic patient, but a myopic patient status. If the macula is involved, especially a retinal detachment, and any symptoms with increased risk of progression to if there is a schisis, then there is greater of photopsia, or changes in vision retinal detachment may well benefit from likelihood of developing an associated should be reported early. prophylactic laser retinopexy. macular hole detachment, which complicates the management further. PERIPHERAL RETINAL CHANGES Myopia also leads to earlier vitreous IN MYOPIA liquefaction, resulting in a posterior vitreous A is performed in the majority If we use our wallpaper analogy we can detachment (PVD). In various cohort of cases, often supplemented with oil appreciate that the peripheral retina in a studies, around 50 per cent of all patients and/or , depending on 38 miophthalmology

the detachment. In a high myope, a peribulbar anaesthesia at the time of cataract features, they should be referred urgently thinner and more elastic provides surgery. Knowing this will allow the surgeon for a full indented examination. A macula- a further challenge for buckling. From to consider alternative methods of measuring on detachment has much better visual the detachment, but also due to the axial length as well as plan for an alternative, outcome than a macula-off detachment. vitrectomy surgery and the use of a gas safer mode of anaesthesia administration at For those being referred for cataract or oil tamponade, patients can develop the time of surgery. surgery, the fundus should be reviewed early cataracts. This makes it important thoroughly and the patient should be Myopic patients who have undergone to we counsel our young detachment counselled about the limitations that may cataract surgery tend to be among the patients that they will lose remain due to their myopic maculopathy. most grateful. Not only do they have following cataract surgery, and may need better vision after having had their Our advice to patients – especially rural earlier surgery in their other eye due to cataract removed, they have also had ones – who notice new vision symptoms, anisometropic symptoms. their high myopia significantly reduced. is to urgently visit their local optometrists Following recovery from retinal However, it is important to always rather than the emergency department or detachment surgery, a patient gets to remember that while patients can be their GP. know their optometrist well, as they make functionally emmetropic post-surgery, adjustments to maximise their vision with the myopic retinal changes remain. As MYOPIA ISSUE their developing early cataracts, loss of a result, they will still require frequent Dr. Abhishek Sharma is a retinal specialist at Queensland Eye Institute in Brisbane. His specialties accommodation, or ! follow-up at least on a four to six monthly include retinal surgery for macular holes, epiretinal basis for the first year following cataract membranes and retinal detachments, as well

THE CATARACT SURGERY IN surgery and yearly thereafter. MYOPIC PATIENTS as treatment for macular degeneration and severe diabetes. He is the author of Mindmaps in Performing cataract surgery in myopic published through CRC Press. patients can be extremely challenging. Dr. Christolyn Raj is a retinal specialist with Sunbury A step-wise approach to surgical co- Eye Surgeons and Vision Eye Institute at Camberwell management is therefore very important, and Coburg, Victoria. SHe specializes in medical in order to educate patients on why retina, cataract/ and paediatric their surgical pathway may differ from “Our advice to patients retinal . She is an Honorary Senior non-myopic patients. It can also help Lecturer at The University of Melbourne. us, as clinicians, to pre-empt potential – especially rural ones complications and address risk factors References before they have a chance to develop into – who notice new 1. Iwase A et al. 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Isr Med Assoc J 2006; 8:880-881. The most commonly discussed cataract department or their GP” 5. Kelliher C, Kenny D and O'Brien C. Trends in blind surgery risk for highly myopic patients registration in the adult population of the Republic of is retinal detachment. This makes a Ireland 1996-2003. Br J Ophthalmol 2006; 90:367-371. peripheral retinal examination mandatory 6. Gaucher D et al. Long-term follow-up of high myopic for these patients. Peripheral retinal foveoschisis: natural course and surgical outcome. Am J weakness can increase the risk of a CONCLUSION Ophthalmol 2007; 143:455-462. postoperative retinal detachment. Some The retina is where the maximum damage 7. Ikuno Y and Tano Y. Vitrectomy for macular holes studies have shown that the risk of retinal from high myopia occurs. As vision associated with myopic foveoschisis. Am J Ophthalmol 2006; 141:774-776. detachment increases with increasing axial specialists, we need to recognise the myopic 8. Jo Y, Ikuno Y and Nishida K. : a predictive length. In one study, an axial length > patients at risk of retinal pathology, and factor in vitrectomy for macular holes without retinal 26.0mm was associated with a 0.9-3.8 per warn them frequently about peripheral and detachment in highly myopic eyes. Br J Ophthalmol 2012; cent risk of retinal detachment while axial central retinal symptoms. These patients 96:197-200. lengths of > 27.0mm and > 29.0mm were can require more frequent follow-up, with 9. Hsiang HW et al. Clinical characteristics of posterior associated with risks of 0.5-6.5 per cent, a higher need for OCT scans and a greater staphyloma in eyes with pathologic myopia. Am J Ophthalmol 2008; 146:102-110. and1.3-8.0 per cent.12,13 Any retinal tears chance of requiring urgent retinal treatment 10. Ohno-Matsui K et al. Patchy atrophy and lacquer in the superior retina, or associated with or surgery. cracks predispose to the development of choroidal lattice, may well benefit from prophylactic In patients with suspected myopic neovascularisation in pathological myopia. Br J Ophthalmol laser retinopexy pre-operatively. 2003; 87:570-573. maculopathy, an OCT has become an 11. Chhablani J et al. Intravitreal monotherapy All myopic eyes with any retinal breaks essential tool, and serial OCTs over months in myopic choroidal neovascularisation: 5-year outcomes should be followed up after surgery with or years are especially helpful. If there has for the PAN-American Collaborative Retina Study Group. Br a dilated fundus examination. The other been a decline in central vision in these J Ophthalmol 2017. important pathology to look for is a patients, they should be referred onto a 12. Bernheim D et al. Comparative prospective study posterior staphyloma, often associated with retinal specialist urgently within a week or of rhegmatogenous retinal detachments in phakic or the . This can often complicate earlier depending on findings. Similarly, in pseudophakic patients with high myopia. Retina 2013; 33:2039-2048. the measurement of the true axial length. high-myope patients with peripheral retinal 13. Zuberbuhler B, Seyedian M and Tuft S. Additionally, an eye with a staphyloma is symptoms, a thorough fundus check should Phacoemulsification in eyes with extreme axial myopia. J at increased risk of perforation from be done. If there is any concern or unusual Cataract Refract Surg 2009; 35:335-340.