Predicting future axial length in patients with paediatric cataract and primary intraocular lens implantation

Abstract

Objective: Creating a model to predict Axial Length (AL) growth in paediatric cataract and evaluating influence factors. Material and methods: Eyes with AL measured at surgery and at least one measurement after a 6-month period, from children with unilateral or bilateral cataract and primary IOL implantation, were evaluated. A “rate of axial length growth” (RALG) was calculated for every single eye using these AL measurements and log10 age. One average RALG was calculated for All Eyes and for the groups of Bilateral and Unilateral, Gender, Age at the Surgery, different Visual Acuity, Bilateral Excluded and Not-excluded eye, and Affected and Not-affected eye in unilateral, for comparisons. Results: Average age at surgery from 76 children was 2.83 ± 2.74 (0.11–12.21) years with follow up of 2.84 ± 1.84 (0.52–8.17) years, 29 (37.66%) had unilateral cataract. A total of 357 AL measurements were used, average of 4.70 ± 2.13 (2–10) measurements per eye. The average RALG for all eyes was 4.51 ± 3.06. There were no RALG significant differences comparing Unilateral and Bilateral eyes ( p = 0.51), Male and Female ( p = 0.26), Age at Surgery <0.5 and >0.5 years old ( p = 0.21), both eyes in Bilateral cases ( p = 0.70) and Unilateral Affected and Not-affected eyes ( p = 0.18). The equation Al = initial AL + slope × Log10 ((age + 0.6)⁄(initial age = 0.6)) estimates ALs in different ages. Conclusions: A model to predict AL growth in paediatric cataract was developed. Different studied factors did not significantly influence AL growth.

Intraocular lens power estimation for future emmetropia in pediatric cataract surgery

“…Only bilateral congenital/ developmental cataract eyes were selected in the present study, although most previous studies have included eyes with unilateral cataracts (5,7,(10)(11)(12)(13)(14)(15)(16)(17) . Children's eyes with unilateral cataracts are subjected to other abnormalities that might affect growth; they are frequently smaller than fellow normal eyes (10) and often associated with alterations including persistent fetal vasculature (18) .…”

“…In the literature, two approaches may be considered to evaluate eye growth: each eye being denoted by a point on the K and AL scatterplots as a function of the age, disregarding the particular dynamic growth of each eye (10)(11)(12)(13) , or considering the dynamic growth of each eye separately, using serial measurements taken during the patients' growth to create linear (6) or logarithmic regression (7,(14)(15)(16)(17) . The regressions allows to use eyes operated on at different ages, with different follow up, and diffe-rent number of measurements within the same sample (5) .…”

“…A new exam with at least three months after surgery was accepted as an inclusion criterion for patients operated on younger than six months old, whereas for patients operated on older than six months old, the required time interval for a new exam was at least six months. This is due to the fact that K flattens and Al grows quickly in the early ages, and using the log model a few months in the first year could represent a larger segment in the x-axis, which corresponds to the age, than the years in older ages (7) . Despite that, the shortest follow-up in the study was 4.8 months.…”

“…This could be positive, if the variable increases with age (AL), or negative if it decreases (K). Through the linearization process, the logarithmic regression can be transformed into a straight line, changing the scale of the axis-x from linear to logarithmic, making possible to obtain the regression using two (or more) points (i.e., two or more values of K and AL observed at different ages) (7) .…”

“…Estimations based on refraction have been used for the past 20 years, because the postoperative refraction is easily obtained, but it is an indirect way to estimate the eye grow. Recent publications shows the advantage of using serial measurement of AL to estimate the evolution of AL with the age to better verify the future myopization (6,7) .…”