The age parameters of the corneal diameter in the patients with the different types of myopia and in the persons with emmetropia and hyperopia
E. B. Maliyeva, H. H. Bushuieva N.N.
SI «The Filatov Institute of Eye Diseases and Tissue Therapy NAMS of Ukraine»
In recent decades in developed countries appeared threatening trend progression of myopia. Given the variety of factors of myopia and the diversity of the existing classifications suggests that myopia is not a single disease. The aim of our research was the study of age parameters corneal diameter in patients with different types of myopia and in persons with hypermetropia and emmetropia.
Materials and methods. 264patients (502 eyes) with varying degrees of myopia allocated to the group by type of myopia: refractive — 133 eyes, axial — 217 eyes, mixed — 91 eyes, and combined — 61 eyes. The patients with different types of myopia were divided by age: group 1 — children 6—10 years; group 2 — adolescents aged 11—15years; group 3 — students of secondary and higher educational institutions of 16—25years; group 4 — older than 25years of age. The persons with hyperopia (81 eyes) and emmetropia (145 eyes) which were allocated in similar age groups was examined.
Methods: visometry for distance, refraktometry with cyclomed 1 %, horizontal corneal diameter (DR) (KR-8900 Topcon and HRK-7000 Huvitz).
Results. In the general group with axial myopia average value of the corneal diameter (12,01±0,33) mm was reliably higher in comparison with refractive (11,60+0,35) mm (p<0.01), combined (11,86+0,40) mm (p<0.01) and mixed myopia (11,71+0,28) mm (p<0.01). In the group of refractive myopia average values of the corneal diameter was substantially less (11,60+0,35) mm than in another groups with different types of myopia (p< 0.01). In the different age group the lowest average values of the corneal diameter were in patients with refractive myopia: 6—10years — (11,64+0,42) mm; 11—15years — (11,57+0,31) mm, 16—25 years — (11.61+0,28) mm, over 25 years — (11,58+0,37) mm in comparing with another different types of myopia (p<0.01; p<0.05). The highest average values of the corneal diameter were found in the group with axial myopia in all age groups: 6—10 years — (12,05+0,35) mm; 11—15 years — (12,00+0,38) mm; 16—25years — (12,10+0,33) mm, over 25years — (11,91+0,31) mm (p<0.01;p<0.05).
Conclusions. Significant differences of the average values of corneal diameter were revealed between the groups of patients with different types of myopia. The average values of the corneal diameter of the axial myopia exceed average values of the corneal diameter of the other kinds of myopia in the all age groups, the lowest average values of the diameter of a cornea marked in patients with refractive myopia comparing another types of myopia in all age groups (p<0.01;p<0.05).
Key words: myopia, emmetropia, hyperopia, corneal diameter
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