Myopia: Risk Factor for Ocular Morbidity and Permanent Visual Loss
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Myopia, or nearsightedness, is increasing globally and is a major risk factor for ocular morbidity and permanent vision loss. High myopia, defined as a refractive error of -5.00 diopters or worse, increases the risks of conditions like myopic macular degeneration, retinal detachment, glaucoma and cataracts which can cause irreversible vision impairment or blindness. Myopic macular degeneration, characterized by diffuse macular atrophy and tears in the retina, is the leading cause of permanent vision loss from high myopia. Preventing the progression of myopia through lifestyle factors like more time outdoors is important to reduce the growing burden of myopia-related blindness worldwide.
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Myopia: Risk Factor for Ocular Morbidity and Permanent Visual Loss
- 1. MYOPIA: RISK FACTOR FOR OCULAR MORBIDITY & PERMANENT VISUAL LOSS https://www.medicinatv.com ALVINA PAULINE DY SANTIAGO, MD AUGUST 30, 2019
- 2. Affiliations & Disclosures No financial interests
- 3. OBJECTIVES Define Myopia, High Myopia, Pathologic Myopia Identify causes of ocular morbidity due to myopia Enumerate the causes of permanent visual loss in myopia Discuss myopic macular degeneration and its sequelae
- 5. Definition: Myopia spherical equivalent objective refractive error is -0.50 or worse Joint report WHO-BHVI, 2017 https://img.webmd.com
- 6. MYOPIA AXIAL MYOPIA: Increased axial length CURVATURAL MYOPIA: Increased curvature of cornea or lens INDEX MYOPIA: increase in refractive index of lens seen in nuclear sclerosis MYOPIA DUE TO EXCESSIVE ACCOMMODATION: seen in patients with accommodative spasm https://www.slideshare.net/aryalmanu/myopia-37170766https://img.ledsmagazine.com
- 7. Definition: High Myopia High Myopia </= -5.00 ◦ Uncorrected acuity 6/172 ◦ Worse than blindness threshold of <3/60 (6/120) in better eye Joint report WHO-BHVI, 2017 spherical equivalent objective refractive error is -5.00 or worse ◦ </= -6.00 D ◦ </= -8.00 D ◦ Axial length > 26 mm
- 8. Definition: Pathologic Myopia (degenerative myopia, malignant myopia) Presence of vision threatening changes in retina Posterior staphyloma High myopia + myopia- related fundus abnormalities such as myopic macular degeneration or glaucoma Joint report WHO-BHVI, 2017 https://webeye.ophth.uiowa.edu
- 9. Causes of Myopia Optical: Peripheral Defocus Intense near work Not enough time spent outdoors Genetics https://www.ahaparenting.com http://www.pointsdevue.com https://s3-ap-southeast- 1.amazonaws.com https://ugc.futurelearn.com
- 10. MYOPIA OCULAR MORBIDITY AMBLYOPIA STRABISMUS HEAVY EYE SYNDROME https://m4.healio.com
- 11. Consequences of High Myopia MYOPIC MACULAR DEGENERATION MYOPIC CHOROIDAL NEOVASCULARIZATION RETINAL DETACHMENT GLAUCOMA CATARACTS https://www.researchgate.net https://imagebank.asrs.org https://www.thelancet.com https://journals.plos.org https://endmyopia.org/
- 12. Consequences of Myopic Macular Degeneration (MMD) SEED Study (Sg Epidemiology of Eye Diseases Study) 2018 ◦ >/= 40 years old (Mean 57 + 9.5) ◦ 8716 phakic patients ◦ Malays, Indians, Chinese (1:1:1) ◦ Myopia: 37.5%, High Myopia (<-5.0) 6.0% ◦ MMD Prevalence: 3.8% overall ◦ 7.7% low to moderate myopes ◦ 28.7% high myopes ◦ MMD increased with degree of myopia and age ◦ 1 in 26 phakic adults with MMD in Sg ◦ Wong et al 2018 https://www.researchgate.net https://imagebank.asrs.org
- 15. Myopic Maculopathy or Myopic Macular Degeneration Vision threatening Usually high myopia Diffuse patchy macular atrophy +/- lacquer cracks +/- choroidal neovascularization https://www.researchgate.net
- 16. Joint report WHO-BHVI, 2017 https://www.verywellhealt h.com NORMAL
- 17. Myopic Macular Degeneration Epidemiological surveys Rapid assessment of avoidable blindness (RAAB), WHO Protocol Consistent use of terminology Accurate data on prevalence of myopia and high myopia o vision not improved by pinhole and cannot be attributed to other causes o direct ophthalmoscopy worse or equal to -5.0D with retinal changes o or, worse or equal to -10.00 D Joint report WHO-BHVI, 2017
- 18. Joint report WHO-BHVI, 2017
- 19. Myopia & Glaucoma Population based studies: risk of glaucoma increases with increasing myopia ◦ Chen et al 2012 Population Study Relationship with glaucoma Blue Mountain Eye Study Odds ratio 2.3 in low myopia; 3.3 in moderate to high myopia (worse than -3.0 D) Barbados Eye Study (Blacks) Myopia one of several risk factors Beaver Dam Eye Study Myopics 60% more likely to have glaucoma than emmetropes Singapore Malays Eye Study 3x higher risk of POAG if -4.0D or worse Beijing Eye Study -6.0 D risk factor in glaucomatous optic neuropathy https://journals.plos.org
- 20. https://www.researchgate.net Myopia & Cataract Simple myopia does not appear to predispose to cataract Nuclear sclerosis leads to refractive myopic change High myopia associated with cataract ◦ Brown and Hill 1987
- 21. Myopia & Cataract High myopia (-6D or worse) associated with incident nuclear cataract (Odds ratio [OR] 3.3) Incident posterior subcapsular cataract and myopia ◦ any myopia (OR: 2.1), ◦ moderate to high myopia (worse than -3.5D: OR 4.4) Use of distance glasses before age 20 (OR 3.0) Incident cataract surgery and myopia ◦ any myopia (OR 2.1); ◦ moderate myopia (-3.5 to -6.0D: OR 2.0); ◦ high myopia (worse than -6.0, OR 3.4) ◦ Younan, Mitchell, Cumming et al, Blue Mountains Eye Study 2002 https://www.australia.com
- 22. Myopia & Cataract More difficult cataract surgery in myopes ◦ Less precise IOL calculations ◦ More complications: ◦ posterior wall collapse ◦ Hypotony ◦ Chong and Mehta 2016 https://eyeworld-websupport911.netdna-ssl.com
- 23. Key points There is a myopia epidemic, predicted to affect 50% of population by 2050. WHO prefers to define high myopia as -5.0D or worse (some studies use -6.0D or -8.0D as cutoff) Morbidity from myopia includes amblyopia, strabismus, heavy eye syndrome, myopic macular degeneration, choroidal neovascularization, retinal detachment, glaucoma and cataracts. Pathologic myopia can lead to myopic macular degeneration and choroidal neovascularization that can lead to permanent loss of central vision. High myopes are more prone to retinal detachments. High myopia is associated with glaucoma and cataracts.
- 24. References 1. The impact of myopia and high myopia: report of the Joint World Health Organization–Brien Holden Vision Institute Global Scientific Meeting on Myopia, University of New South Wales, Sydney, Australia, 16–18 March 2015. Geneva: World Health Organization; 2017. Licence: CC BY-NC-SA 3.0 IGO. © WHO 2017. https://www.who.int/blindness/causes/MyopiaReportforWeb.pdf. Accessed August 26, 2019 2. Holden BA, Fricke TR, Wilson DA et al. Global prevalence of myopia and high myopia and temporal trends from 2000 through 2050. Ophthalmology 2016; 123 (5), 1036-1042 Licence: CC By-NC-ND. https://www.aaojournal.org/article/S0161-6420(16)00025-7/pdf. Accessed August 26, 2019. 3. Aryal M, Myopia. https://www.slideshare.net/aryalmanu/myopia-37170766. Accessed August 26, 2019. 4. Tan RJ, Demer JL. Heavy eye syndrome vs sagging eye syndrome in high myopia. J AAPOS 2015; 19 (6): 500-506. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4688571/pdf/nihms733942.pdf. Accessed August 26, 2019. 5. Verhoeven VJ, et al. for the Consortium for refractive error and myopia (CREAM). Genome wide meta analyses of multi-ancestry cohorts,identify multiple new susceptibility loci for refractive error and myopia. Nature 2013; Nature Genetics 45: 314-318. 6. Mitchell P, Hourihan F., Sandbach J, et al. The relationship between glaucoma and myopia. The blue mountains eye study. Ophthalmology 1999; 106: 2010-2015. https://www.aaojournal.org/article/S0161-6420(99)90416-5/pdf. Accessed August 26, 2019 7. Chen SJ, Lu P, Zhang WF et al. High Myopia as a risk factor in primary open angle glaucoma. Int J Ophthalmol 2012; 5: 750-753. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3530820/pdf/ijo-05-06-750.pdf. Accessed August 26, 2019.
- 25. References 7. Brown NA, Hill AR. Cataract: the relation between myopia and cataract morphology. Br J Ophthalmol 1987; 71: 405-414. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1041188/pdf/brjopthal00616-0002.pdf. Accessed August 26, 2019 8. Kubo E, Kumamoto Y, Tsuzuki S, et al. Axial length, myopia, and the severity of lens opacity at the time of cataract surgery. Arch Ophthalmol 2006; 124: 1586-1590. https://scholar.google.com/scholar_url?url=https://jamanetwork.com/journals/jamaophthalmology/articlepdf/418690/ecs60043_1586_ 1590.pdf&hl=en&sa=T&oi=ucasa&ct=ufr&ei=JepjXeSCLMGeywTjvYmABA&scisig=AAGBfm3bYtjc_QXgTcnGRHJCo9Z0d9xSOw. Accessed August 26, 2019. 9. Deitz GA, Sweeney AR, Jung HC. Posterior wall collapse in high myopia following cataract surgery. Case Report Ophthalmol 2018; 9: 167-171. https://www.karger.com/Article/Pdf/487077. Accessed August 26, 2019. 10. Chong E, Mehta J. High myopia and cataract surgery. Current Opinion in Ophthalmology 2016; 27: 45-50. https://journals.lww.com/co- ophthalmology/Abstract/2016/01000/High_myopia_and_cataract_surgery.8.aspx. Accessed August 26, 2019. 11. Younan C, Mitchell P, Cumming RG, et al. Myopia and incident cataract and cataract surgery: The Blue Mountains Eye Study. Invest Ophthalmol Vis Sci 2002; 43: 3625-3632. https://iovs.arvojournals.org/article.aspx?articleid=2162247. Accessed August 26, 2019. 12. Wong YL, Sabanayagam C, Ding Y et al. Prevalence, risk factors and impact of myopic macular degeneration on visual impairment and functioning among adults in Singapore. Invest Ophthalmol Vis Sci 2018; 59: 4604-4613. https://iovs.arvojournals.org/article.aspx?articleid=2702940. Accessed August 27, 2019.
- 26. #myopia © AP Santiago 2019 August 30, 2019 Seeing the world through the eyes of a child, Is the purest joy that anyone can experience. -Constance Zimmer https://expertbeacon.com
Editor's Notes
- Good morning. From the Philippine Eye Research Instititute, this is Dr. Pauline Santiago. We are here to discuss myopia as a risk factor for ocular morbidity and permanent visual loss.
- These are my affiliations, but I have no financial interests to disclose.
- At the end of this session, we should be able to define myopia, high myopia, pathologic myopia; identify causes of ocular morbidity due to myopia; enumerate the causes of permanent visual loss in myopia; and discuss myopic macular degeneration in greater detail
- Why are we talking about Myopia today? Is this not just near sightedness and a matter of wearing the correct prescription? The reason is this. This is a slide from the Brien Holden Vision Institute. This is where we are now, [CLICK] where about 30% of the population or more than 2000M are myopic, 10% of whom or 2.8% are high myopes. If this trend continues, [CLICK] it is projected that 50% of the world population will be myopic by the year 20/50. More severe in Asia Pacific region Highest in East Asia: China, Japan, Korea, Singapore
- What is myopia. It is defined as an objective refraction with a sp
- Regardless of the cause for the myopia, parallel light rays falls in front of the retina and are not focused.
- Several cut-offs for high myopia are used in various studies, [CLICK] but the WHO-BHVI joint report recommends -5.00D. [CLICK] The reason being, that the uncorrected visual acuity of a patient with a -5.0D error is 6/172, is worse than the blindness threshold of 3/60 in the better eye.
- We also need to define pathologic myopia, which is synonymous with degenerative myopia or malignant myopia. There are changes in the retina that threatens vision; other authors equate pathologic myopia with posterior staphyloma, but the joint report of the WHO and the BHVI uses the definition high myopia with myopia-related fundus abnormalities as the definition of pathologic myopia.
- Some of the cause of myopia are peripheral defocus, intense near work, propensity to stay indoors, and maybe a genetic predisposition in some cases especially when both parents are myopic. The Consortium for refractive errors and myopia were also able to identify several genes for myopia.
- Uncorrected myopia can cause amblyopia and strabismus. In extreme cases of high myopia the patient can have what is clinically recognized as the heavy eye syndrome. Amblyopia due to myopia is treated by correction and patching, strabismus is treated by giving of glasses if there is significant refractive error, patching if the patient is amblyopic, and surgery for any residual deviation. The heavy eye syndrome will require strabismus surgical intervention aside from correction of the refractive error.
- More importantly, high myopia can lead to sequalae such as myopic macular degeneration, which in turn may lead to choroidal neovascularization especially in patients with lacquer cracks. High myopes are also more prone to develop retinal detachments, and have a higher incidence of glaucoma, as well as cataracts.
- In the past, the prevalence of myopic macular degeneration remained largely unknown. Until the SEED study of Singapore published in 2018. The SEED study followed WHO definitions of MMD and high myopia we discussed here. 37.5% of patients older than 40 were myopic, 6.5% were high myopes. MMD occurred in close to 8% in low to moderate myopia, but occurs 3x more often in high myopes.
- [CLICK] This is what a patient with normal vision sees, [CLICK x 2] a patient with retinal detachment will see a curtain obstructing field of vision, [CLICK X2] and a patient with myopic maculopathy will see a central scotoma in his field of vision.
- These are how the fundus appears in the normal patient, the eye with the retinal detachment--there is a hole with an inferior detachment, and finally an eye with myopic macular degeneration. This picture shows chorioretinal atrophy and choroidal neovascularization.
- What is myopic maculopathy or myopic macular degeneration? it is a vision threatening condition, usually of patients with high myopia, with diffuse macular atrophy, with or without lacquer cracks, and/or choroidal neovascularization.
- The normal fundus picture is placed here for comparison. These are pictures of MMD-- this is diffuse chorioretinal atrophy, patchy atrophy, lacquer cracks, choroidal neovascularization or CNV, and CNV with macular atrophy.
- We are belaboring MMD because it important to be recognized in epidemiological surveys, and should be included in RAAB consistent with the WHO protocol. Consistent use of terminology and definitions permit accurate data on prevalence of myopia and high myopia. On the field, vision that is not improved with pinhole, cannot be attributed to other causes, and with a direct ophthalmoscope dial at -5.0 or higher with retinal changes seen, OR when the dial is worse than or equal to -10D is considered MMD for RAAB purposes
- Pathologic myopia has a prevalence of 1-3% in the general adult population. The estimated prevalence of visual impairment estimated at 1-15 per 1000 population, and an annual incidence of blindness ranging for 1-10 per 100,000. [CLICK] Notice how these parameters are consistently worse in the asian population
- Briefly, population based studies have consistently documented the association of increasing myopia with glaucomatous optic neuropathy and glaucoma. ODDS RATIO: Odds ratio greater than 1 indicates condition more likely to occur Measure of association between exposure and outcome “odds outcome will occur given an exposure” Case control, cross sectional or cohort studies
- as for cataract associations, simple myopia (less than -5.0D to -6.0D) does not appear to predispose to cataracts. Sometimes it is the presence of nuclear sclerosis that leads to refractive myopic changes. High myopia however, is associated with cataracts.
- This is confirmed dn the Blue Mountain Eye Study which documented the association of cataracts with worsening myopia. Incident posterior nuclear cataracts, posterior subcapsular cataract, and incident cataract surgery were all associated myopia, especially with higher degrees of myopia.
- More challenging cataract surgery is experienced in myopic patients. Not only is IOL calculation less precise, the actual surgery is also more difficult. Reported complications include posterior wall collapse and hypotony, and in themselves potentially visually threatening.
- Summary of our key points in this discussion. 1. THere is a myopia epidemic that can affect more than 50% of the world by 2050. 2. WHO prefers to use -5.0D as a cut off for high myopia but earlier studies use -6.0D, and even -8.0D. 3. Morbidity from myopia includes amblyopia, strabismus and heavy eye syndrome. 4. Pathologic myopia leads to more permanent visual loss due to myopic macular degeneration, choroidal neovascularization, that can lead to central loss of vision. 5. High myopes are more prone to retinal detachments, which if left unrecognized can lead to permanant visual loss. 6. High myopia is associated with glaucoma and cataracts.
- This is my last slide… I am ready to turn over the microphone to Dr. ____