Abstract
Purpose: :
To study the biomechanical parameters of the corneoscleral tunic and biomechanical/biochemical parameters of connective tissue (CT) in children with progressive myopia.
Methods: :
The study included 155 children aged 9-17: 18 had emmetropia or hyperopia; 20 - mild myopia; 32 - moderate myopia; 85 - high myopia. 32 children had pathological myopia (PM) due to peripheral retinal degeneration (PRD). We measured corneal hysteresis (CH) (ORA, Reichert), scleral acoustic density (SAD) (Voluson 730Pro), vertebral X-ray, plantography, arthral mobility, serum cortisol (SC), vegetative balance (Kerdo index).
Results: :
CH (mmHg) and SAD (U) (Mean±St.Err) decreased with higher myopia: in mild myopia, CH was 13.0±0.3, in moderate myopia, 12.2±0.3*, in high myopia, 11.0±0.3*; SAD was resp. 218.0±7.1, 202.0±6.9* and 188.9±5.6* (*: p<0.05 as compared to mild myopia). In congenital myopia, CH was 11.4±0.3 and SAD - 199.0±6.3, which was greater than in acquired myopia: CH - 10.7±0.3, SAD - 188.2±8.4 (p<0.05 for both parameters). The lowest CH (10.4±0.4) and SAD (174.5±9.6) were found in acquired PM; in myopia without PRD, CH was 10.9±0.5 and SAD 195.0±10.0. Congenital PM showed CH of 11.8±0.7 and SAD of 206.0±9.9, which was greater than in acquired PM (p0.05). CT dysplasia progressed with higher myopia: it was found in 57% of children with mild, 82% with moderate, 88.1% with high and 100% with congenital myopia. Biomechanical defects of CT and hormonal imbalance were associated with vegetative nervous system (VNS) disorders: in moderate and high myopia only 17.5% children were eutonic, 27.5% vagotonic and 55% sympatotonic.
Conclusions: :
Children with progressive myopia showed biomechanical anomalies of corneosclera along with CT dysplasia, a decreased SC level and imbalanced VNS. These characteristics of congenital and pathologic myopia need to be taken into account in the prognosis of their progression and eye fundus complications.
Keywords: myopia • sclera • extracellular matrix