IoLunder2 study phenotypes, outcome definitions and the potential predictors of outcome considered in statistical analysis
| Phenotypes | |
|---|---|
| Microphthalmos | Ocular axial length 15.5 mm at any age, or <17.5 mm if aged 1 month or older, <18 mm if aged 3 months or older, <19 mm if aged 6 months or older, or <20 mm if aged 2 years or older |
| Significant microphthalmos | Axial length <16 mm |
| Microcornea | Horizontal corneal diameter (HCD) <9.5 mm at any age, <10 mm if aged over 1 month old, or <10.5 mm in children over 6 months old |
| Persistent fetal vasculature | Any persistence of fetal intraocular vasculature detected preoperatively or peroperatively10 |
| Significant coexistent ocular abnormality | HCD<9.5 mm or axial length <16 mm or persistent ocular fetal vasculature (PFV) involving the anterior segment of the eye, or complex PFV, or other anterior segment or posterior segment abnormality |
| Outcomes | |
| Visual outcome | Level 3: Acuity within normal range for age*Level 2: Acuity worse than lower limit of normal range*Level 1: Unable to fix AND follow* |
| Potential predictors of visual outcome | Intraocular lens (IoL) implantation, age at diagnosis, time from diagnosis of cataract to surgery, socioeconomic status, (gestational) age at surgery, age at visual assessment, axial length, HCD, compliance with occlusion and correction, surgeon, surgical technique; and the presence of microphthalmos, an interocular axial length difference, a significant ocular anomaly, preoperative nystagmus or strabismus, medical disorder or impairment, peroperative complication, postoperative visual axis opacity (VAO), glaucoma or other complication or secondary intraocular procedure. In bilateral cases, asymmetry of opacity was also considered as a potential predictor of visual outcome |
| Secondary glaucoma | Presence of a combination of signs consistent with IOP ≥21 mm Hg, eg, optic disc cupping ≥0.3/asymmetry ≥0.2/progression, corneal changes, progressive myopia (British Infantile and Childhood Glaucoma (BIG) Eye Study definition) |
| Potential predictors of incidence of glaucoma | Age (gestational) at surgery, cataract morphology, axial length, significant interocular axial length difference, HCD, surgeon, surgical technique, the presence of persistent fetal vasculature, peroperative iris trauma, peroperative IoL explantation, postoperative inflammation, postoperative inflammation or postoperative intraocular surgery, the use of posterior capsulotomy, oculoviscous devices, IoL implantation, postoperative intensive steroid drops, and postoperative systemic steroid |
| VAO | Lens proliferation into axis or inflammatory/pupillary membrane across axis or capsular phimosis |
| Potential predictors of incidence of VAO | Age (gestational) at surgery, axial length, HCD, surgeon, the presence of persistent fetal vasculature, peroperative iris trauma, peroperative IoL explantation, postoperative inflammation, anterior/posterior capsulotomy technique, IoL implantation, IoL power, single piece IoLs, IoL fixation position, peroperative heparin, postoperative intensive steroid regimen, and postoperative systemic steroid |
*Lower limit of normal range for age: Worse than 0.8 logMAR for those aged under 18 months, 0.7 aged 18–24 m, 0.6 aged 24–30 months, 0.5 aged over 30 m on Teller grating card preferential looking, and worse than 0.6 logMAR for those aged under 18 months, 0.4 aged 18–24 m, 0.3 aged 24–36 m on Cardiff card acuity testing.
IOP, intraocular pressure.