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Evaluation of the Relationship between Corneal Diameter and Lens Diameter in Children

Original article

Abstrak

Kajian ini bertujuan untuk mengkaji hubung kait antara diameter kornea dan diameter kanta di kalangan kanak-kanak. Kajian ini melibatkan sejumlah empat puluh kanak-kanak (40 mata) yang kurang daripada 4 tahun yang menjalani pemeriksaan, prosedur atau pembedahan di Hospital Kuala Lumpur dari Januari 2010 sehingga September 2011. Pemeriksaan dijalankan dengan menggunakan bius am di dewan bedah. Diameter kornea diukur dengan ‘Holladay-Godwin cornea gauge’ sementara diameter kanta diukur dengan menggunakan mesin ultrasound yang mempunyai resolusi tinggi ‘ultrasound biomicroscope (UBM)’. Purata umur populasi kajian adalah 24.7 + 12.1 bulan. Purata diameter kornea melintang adalah 11.62 + 0.50 mm, lebih besar berbanding dengan purata diameter kornea menegak yang berukuran 11.20 + 0.58 mm. Purata diameter kanta adalah 7.94 + 0.47 mm. Diameter kornea didapati mempunyai korelasi positif yang sederhana dengan diameter kanta (r=0.479, p=0.002). Terdapat hubung kait yang kukuh di antara diameter kanta dengan umur pesakit (r=0.718, p<0.001). Diameter kanta boleh dikira dengan menggunakan formula: [Diameter kanta (mm) = 7.010 + 0.021 Diameter kornea (mm) + 0.028 Umur (bulan)] (r2=0.52). Kesimpulannya, terdapat hubungkait positif yang sederhana di antara diameter kornea dengan diameter kanta. Mesin UBM boleh digunakan untuk mengukur bag kanta mata secara langsung sebelum pembedahan. 

Abstract

Primary intraocular lens (IOL) implantation has gained acceptance for  management of infantile cataracts because of the advantage of reduced amblyopia risk. The aim of the study was to investigate the association between corneal diameter as measured from the white-to-white distance and natural lens diameter in children. This association may aid intraocular lens selection following cataract removal in infants and young children. A cross-sectional study was performed on forty eyes from 40 children less than 4 years, who needed to be examined, were planned for a procedure or operation under general anaesthesia. Subjects were recruited from Eye Clinic,Kuala Lumpur General Hospital from January 2010 to September 2011.  Corneal diameter was measured with Holladay-Godwin corneal gauge while lens diameter was measured with ultrasound biomicroscope (UBM) during surgery. For the results, mean age of subjects was 24.7 + 12.1 months. Mean corneal diameter was 11.62 + 0.50 mm horizontally and 11.20 + 0.58 mm vertically. Mean horizontal lens diameter was 7.94 + 0.47 mm. A medium positive correlation was found between mean horizontal corneal diameter and lens diameter (r=0.479, p=0.002). Lens diameter had a strong correlation with patient’s age (r=0.718, p<0.001). Lens diameter can be calculated by using this model of equation: [Lens diameter (mm) = 7.010 + 0.021 Corneal Diameter (mm) + 0.028 Age (months)] (r2=0.52). In conclusion, there was a moderate positive correlation between corneal and lens diameter. UBM can be used to measure lens capsular bag size directly preoperatively.