Iridocorneal Angle and Anterior Segment Structure in Eyes of Children With Cataract
Condition: Congenital Cataract
MeSH terms: Cataract
Study type: Observational [Patient Registry]

Summary: 
      The aim of this study is to evaluate the morphology of iridocorneal angle and anterior
      segment structure in children with cataract, and to explore potential preoperative structural
      clues for postoperative glaucoma. The investigators included children with cataract planning
      to have cataract surgery in our institute. For analysis, one eye was randomly selected in a
      case of bilateral cataract via a random table, forming the "bilateral cataract" group; the
      cataractous eyes in cases of unilateral cataract composed the "unilateral cataract" group and
      the fellow non-cataractous eyes made up the "control" group. Exclusion criteria were: a
      history of ocular trauma, a history of intraocular surgery, preoperative glaucoma, steroid
      use before surgery, a history of maternal rubella syndrome, chronic anterior uveitis,
      persistent fetal vasculature, ocular anomalies associated with an increased risk of glaucoma,
      unable to complete examinations. The investigators recorded age at surgery, gender and
      relevant ocular and systemic histories. All patients underwent slit lamp biomicroscopy,
      dilated fundus examination and cycloplegic retinoscopy. In patients with good cooperation,
      The investigators obtained the axial length (AL) using IOL-Master 500 and the intraocular
      pressure (IOP) with a non-contact tonometer. In young patients with poor cooperation, the
      investigators measured the AL with a contact A-scan, the central corneal thickness (CCD)
      value with a handheld pachymeter and the IOP using a handheld tonometer under sedation. With
      a contact A-scan, the AL measurement was repeated 10 times by the same examiner and the mean
      value was analyzed. Corneal diameter was measured with a caliper in the operating room before
      cataract surgery. Under general anesthesia, a pediatric surgeon (YEZ) evaluated the
      iridocorneal angle with an indirect goniolens under the operating microscope. A gentle
      tilting of the goniolens was allowed to obtain a better view of the angle. Another
      experienced pediatric ophthalmologist (DDW) double checked the video recordings and graded
      the details of iridocorneal angle according to the Shaffer and Spaeth classification system
      and standard methods reported. The angle width was defined as follows: grade 0, a closed
      angle without visible angle structures; grade 1, a very narrow angle with Schwalbe's line
      visible only; grade 2, a moderately narrow angle with Schwalbe's line and trabecular meshwork
      visible; grade 3, an open angle with trabecular meshwork and scleral spur visible; grade 4,
      the widest angle with ciliary body band (CBB) visible. The iris insertion and pigmentation of
      the posterior trabecular meshwork were classified according to the Spaeth classification
      system. The iris insertion was defined as follows: A, anterior to Schwalbe's line; B, between
      Schwalbe's line and scleral spur; C, scleral spur visible; D, deep with ciliary body visible;
      E, extremely deep with > 1 mm ciliary body band. The pigmentation of trabecular meshwork was
      defined as follows: 0, no pigment; 1, minimal pigment; 2, mild pigment; 3, moderate pigment;
      4, intense pigment. The number of iris process was defined as follows: 0, none; 1, minimal;
      2, moderate; 3, marked. The width of CBB was graded according to the classification proposed
      by Tawara et al and defined as follows: invisible, the CBB could not be seen at all; very
      narrow, the CBB was narrower than the scleral spur; normal, the CBB was wider than the
      scleral spur. The normality of variables was tested using Kolmogorov-Smirnov test. Continuous
      variables are presented as mean±standard deviation or median (interquartile range) based on
      the normality of variables, and categorical variables are presented as frequencies and
      percentages. One-way ANOVA or Kruskal-Wallis test was used for overall comparison, and
      Dunnett test or Kruskal-Wallis One-way ANOVA was used for paired-comparison of variables
      between groups where appropriate. Mann-Whitney test was used for further subgroup comparison.
      A P value less than 0.05 was considered statistically significant. All statistical analyses
      were performed using SPSS version 21.0 (SPSS Inc, Chicago, Illinois, USA).
    


Intervention name(s): gonioscopy
Intervention type(s): Procedure
Intervention description(s): gonioscopic observation and grading of iridocorneal angle
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Participants included eyes of children with unilateral or bilateral cataract.