title: Association of Axial Length With Risk of Uncorrectable Visual Impairment for Europeans With Myopia.
abstract: OBJECTIVE
  Myopia (ie, nearsightedness) is becoming the most common eye disorder to cause blindness in younger persons in many parts of the world. Visual impairment due to myopia is associated with structural changes of the retina and the globe because of elongation of the eye axis. How axial length-a sum of the anterior chamber depth, lens thickness, and vitreous chamber depth-and myopia relate to the development of visual impairment over time is unknown.
  
  
  OBJECTIVE
  To evaluate the association between axial length, spherical equivalent, and the risk of visual impairment and to make projections of visual impairment for regions with high prevalence rates.
  
  
  METHODS
  This cross-sectional study uses population-based data from the Rotterdam Study I (1990 to 1993), II (2000 to 2002), and III (2006 to 2008) and the Erasmus Rucphen Family Study (2002 to 2005) as well as case-control data from the Myopia Study (2010 to 2012) from the Netherlands. In total, 15 404 individuals with data on spherical equivalent and 9074 individuals with data on axial length were included in the study; right eyes were used for analyses. Data were analyzed from September 2014 to May 2016.
  
  
  METHODS
  Visual impairment and blindness (defined according to the World Health Organization criteria as a visual acuity less than 0.3) and predicted rates of visual impairment specifically for persons with myopia.
  
  
  RESULTS
  Of the 15 693 individuals included in this study, the mean (SD) age was 61.3 (11.4) years, and 8961 (57.1%) were female. Axial length ranged from 15.3 to 37.8 mm; 819 individuals had an axial length of 26 mm or greater. Spherical equivalent ranged from -25 to +14 diopters; 796 persons had high myopia (ie, a spherical equivalent of -6 diopters or less). The prevalence of visual impairment varied from 1.0% to 4.1% in the population-based studies, was 5.4% in the Myopia Study, and was 0.3% in controls. The prevalence of visual impairment rose with increasing axial length and spherical equivalent, with a cumulative incidence (SE) of visual impairment of 3.8% (1.3) for participants aged 75 years with an axial length of 24 to less than 26 mm and greater than 90% (8.1) with an axial length of 30 mm or greater. The cumulative risk (SE) of visual impairment was 5.7% (1.3) for participants aged 60 years and 39% (4.9) for those aged 75 years with a spherical equivalent of -6 diopters or less. Projections of these data suggest that visual impairment will increase 7- to 13-fold by 2055 in high-risk areas.
  
  
  CONCLUSIONS
  This study demonstrated that visual impairment is associated with axial length and spherical equivalent and may be unavoidable at the most extreme values in this population. Developing strategies to prevent the development of myopia and its complications could help to avoid an increase of visual impairment in the working-age population.
authors: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands2Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands.
authors: J Willem L
authors: JW
authors: Tideman
authors: Department of Ophthalmology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors: Margaretha C C
authors: MC
authors: Snabel
authors: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands2Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands.
authors: Milly S
authors: MS
authors: Tedja
authors: Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands.
authors: Gwyneth A
authors: GA
authors: van Rijn
authors: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands.
authors: King T
authors: KT
authors: Wong
authors: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands5Department of Ophthalmology, Albert Schweitzer Hospital, Dordrecht, the Netherlands.
authors: Robert W A M
authors: RW
authors: Kuijpers
authors: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands2Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands.
authors: Johannes R
authors: JR
authors: Vingerling
authors: Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands.
authors: Albert
authors: A
authors: Hofman
authors: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands2Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands.
authors: Gabriëlle H S
authors: GH
authors: Buitendijk
authors: Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands.
authors: Jan E E
authors: JE
authors: Keunen
authors: Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands.
authors: Camiel J F
authors: CJ
authors: Boon
authors: The Rotterdam Eye Hospital, Rotterdam, the Netherlands.
authors: Annette J M
authors: AJ
authors: Geerards
authors: Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands.
authors: Gregorius P M
authors: GP
authors: Luyten
authors: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands2Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands8Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, the Netherlands.
authors: Virginie J M
authors: VJ
authors: Verhoeven
authors: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands2Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands.
authors: Caroline C W
authors: CC
authors: Klaver
mesh_terms: D000368:Aged; D058452:Axial Length, Eye / Q000000981:diagnostic imaging*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D009426:Netherlands / Q000453:epidemiology; D012029:Refraction, Ocular / Q000502:physiology*; D012189:Retrospective Studies; D012307:Risk Factors; D014786:Vision Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D014792:Visual Acuity