Description

Two children with bilateral congenital cataracts were operated for cataract surgery of one eye each. The first was a 6 months old (preterm delivery at 7 months gestation) with no other apparent ocular pathology (figure 1A–C); the second was a 10 months old case of Peter’s anomaly with buphthalmos (figure 2A,B). The second case had 360° of posterior synechiae, a poorly dilating pupil, iris bombe, 360° of anterior synechiae in mid-periphery with peripheral iris totally plastered to cornea (figure 2B). Lensectomy was done through a sub iris route in this case. After lens aspiration/lensectomy and anterior vitrectomy in both cases, posterior segment evaluation was done as a part of routine surgery.1 The illuminator was tilted, and the pattern of iris was visualised against the glow of fundus. In the first case, the entire iris was transilluminating, and ciliary processes were visualised (figure 1C). Deficiency of pigments in iris allowed significant transillumination indicating it being an immature iris. In the second case, the iris peripheral to anterior synechiae was atrophic showing transillumination defect, allowing the pattern of iris muscle fibres to be visualised (figure 2C,D).

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Figure 1

(A) Left eye of a 6-month-old child with congenital cataract; (B) ultrasound biomicroscopy of the same eye showing peripheral iris thinning (white arrow); (C) intraoperative transillumination done with endoilluminator after lens aspiration and anterior vitrectomy showing thin iris with ciliary processes (stars).

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Figure 2

(A) Right eye of 10-month-old child with Peter’s anomaly with bupthalmos with cataract; (B) ultrasound biomicroscopy of the same eye showing iris bombe with 360° anterior synechiae; (C),(D) transillumination as in case 1 with endoilluminator showing thin atrophic see through iris with iris fibre patterns seen.

Transillumination is an examination method in which on slit lamp examination, a co-axial illumination is used through the pupil to illuminate the eye. Transillumination of iris is thus made possible against the glow of the fundus.2 This can be used to detect patency of peripheral iridotomies, localised iris thinning, mid-peripheral defects in pigment dispersion syndrome, diagnosing entities like bilateral acute iris transillumination. Transillumination has only been described on slit lamp examination in the literature. This is not possible in paediatric cases where examination on slit lamp is not possible and also in patients with cataracts that obstruct illumination of fundus. We normally use an endoilluminator in all our paediatric cataract surgery cases for intraoperative posterior segment evaluation using wide angle viewing lenses.1 While manoeuvring the illuminator, we found that this method can also be used to detect transillumination defects in iris as depicted in our images. In the first case, we could even depict ciliary processes (figure 1C) and in the second case, we could depict iris muscle fibre arrangement (figure 2C,D) as shown. Our method is as good as slit lamp method if not better and can prove really helpful in opportunistically detecting thin/atrophic iris or iris defects in paediatric/adult cases intraoperatively during cataract surgeries.