Measurement of biological parameters of nanophthalmos and its correlation with axial length

Abstract

Objective To quantitatively measure biological parameters of nanophthalmos and analyze the correlation between axial length (AL) and the other biological parameters. Methods The clinical data of 71 eyes of 43 patients identified with nanophthalmos (AL≤20 mm) from September 2012 to August 2018 in Zhongshan Ophthalmic Center were retrospectively analyzed.All enrolled patients underwent ophthalmological examinations including best-corrected visual acuity, refraction, slit-lamp biomicroscopy, fundus examination, Goldmann applanation tonometry, A-scan ultrasound examinations, ultrasound biomicroscopy, spectral domain optical coherence tomography (SD-OCT) and nonmydriatic fundus photography.Pearson correlation analysis was used to analyze the relationship between AL and all biological parameters.This study followed the Declaration of Helsinki and was approved by the Ethics Committee of Zhongshan Ophthalmic Center (NO.2017KYPJ092). All patients signed informed consent. Results Of the 43 patients, the average age was (46.00±12.75) years, the mean intraocular pressure was (24.97±14.87)mmHg (1 mmHg=0.133 kPa). The mean best corrected visual acuity was 1.14±0.79, the mean refraction was (11.61±4.09)D.The mean AL, central corneal thickness (CCT), central anterior chamber depth(ACD), anterior chamber width (ACW), len thickness(LT) and vitreous cavity length(VCL) was (17.13±1.57)mm, (550±60)μm, (1.64±0.37)mm, (11.17±0.61)mm, (5.01±0.51)mm and (10.10±1.80)mm, respectively.The average retinal nerve fiber layer thickness (mRNFLT), macular foveal retinal thickness (FRT) and subfoveal choroidal thickness (SFCT) was (98.51±40.93), (294.46±116.83) and (488.72±133.06)μm, respectively.The ratio of ACD to AL, LT to AL, and VCL to AL was 9.6%, 29.4% and 59.3%, respectively.The ACW and VCL were positively correlated with AL(r=0.432, 0.978; both at P 0.05). Conclusions Nanophthalmos has the characteristics of narrow anterior and posterior segment structure.The ratio of LT to AL is increased and the ratio of VCL to AL is decreased.The AL is positively correlated with ACW and VCL, negatively correlated with LT and FRT. Key words: Nanophthalmos; Axial length; Biological parameters; Len thickness; Retinal thickness