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Monica Jong, Padmaja Sankaridurg, Thomas John Naduvilath, wayne li, Mingguang He; The change in AL/CR progression and spherical equivalent progression may predict the risk of high myopia. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5482.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the axial length and corneal radius of curvature (AL/CR) ratio in high versus low myopes and its relationship with myopia progression.
Baseline AL/CR ratio of the right eyes of 310 high myopes (aged 7 to 16; myopia ≤ -6.00D) from the ZOC-BHVI High Myopia Registry (2012- 2013, Guangzhou, China) and 733 low myopes (aged 6 to 16; myopia -0.50D to -3.50D) from Vision CRC studies (2010-2014, Guangzhou, China) were calculated. Exclusion criteria were ocular disease, surgery or previous treatment for myopia. All participants underwent measurement of axial lengths (AL), corneal radii of curvature (CR) and cycloplegic objective refraction. Low myopes were followed 6 monthly for 12 months. Parental myopia was documented. General linear model was used to test the relationship between AL/CR ratio and spherical equivalent (SE) after adjusting for parental myopia, gender, age, and high versus low myopia. The progression in AL/CR ratio with progression in SE was assessed in the slow (≤0.50D) and fast (>0.50D) progressing low myopes.
The mean age of the high myopia group was 12.8±2.3 years; 50% female. The mean SE was -8.5±2.0D (range -6.00 to -19.25D), mean AL was 26.8±1.1 mm (range 24.1–30.1 mm), mean CR was 7.7±0.3 mm (range 7.1–8.5 mm), mean AL/CR ratio was 3.5±0.1 (range 3.2–3.8). The mean age of the low myopia group was 10.0±1.9 years; 49% female. Mean AL was 24.5±0.8 mm (22.2 to 27.2 mm), mean CR was 7.8±0.2 mm (6.8– 8.6 mm), mean AL/CR ratio was 3.2±0.1 (3.0–3.4). Age, gender and parental myopia were associated with AL/CR ratio after adjusting for level of myopia. The AL/CR ratio was significantly higher in high myopes (p<0.001). The relationship of AL/CR ratio with SE at baseline showed that the rate of increase in SE per unit change in AL/CR ratio was 1.8 times higher in high myopes (SE= -11.9xAL/CR+32.7, R2=0.39) compared to low myopes (SE= -6.5xAL/CR+18.4, R2=0.38) (p<0.001). The relationship in the progression variables showed that the annual progression in SE per unit progression in AL/CR was 2.6 times higher in the fast progressing (SE progression= -7.5xAL/CR–0.63, R2=0.27) versus slow progressing low myopes (SE progression=-2.9xAL/CR–0.2, R2=0.13).
The slopes of the progression in AL/CR ratio versus progression in SE are different in fast progressing and slow progressing low myopes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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