TORCH testing in non-familial paediatric cataract

Sir,

As TOxoplasmosis, Rubella, Cytomegalovirus and Herpes Simplex Virus are recognised as potential causative pathogens, it has become common practice to include TORCH serology in the investigation of non-familial paediatric cataracts. The paediatric subsection of the 2010 Royal College of Ophthalmology Cataract Surgery Guidelines endorses this practice.¹ These guidelines reference a 2004 paper by Raghu et al,² which reported four cases of Herpes Simplex Virus (HSV) 1-associated congenital cataract; however, none of the four patients required treatment for HSV. The guidelines do not provide further evidence to support routine TORCH testing.

Following institutional board approval from the Standards, Quality and Audit Department of the Belfast Health and Social Care Trust (BHSCT), the clinical and laboratory findings for paediatric patients (≤16 years old) who underwent cataract surgery between January 2006 and December 2013 were retrospectively analysed using the Northern Ireland Electronic Health Care Record system. Patients with a family history of paediatric cataracts or traumatic cataracts were excluded. TORCH titres had been performed on all 30 patients identified with non-familial paediatric cataract in this study. Five children had abnormal results; of these, one was an insufficient sample, one was a raised CMV on PCR and three further ‘positive’ results were considered insignificant on discussion with virology colleagues (Table 1). The characteristics of these 5 patients are given in Table 2. None of the five patients with abnormal results had raised IgM and none required treatment for any of the TORCH organisms.

Table 1 Results of TORCH serology in 30 patients with non-familial paediatric cataract

Table 2 Characteristics of the five patients with ‘abnormal’ TORCH serology

The UK vaccination programme includes MMR vaccine at 12–13 months of age. Children who have received the MMR vaccination will yield a positive IgG result on rubella testing. Two of the insignificant ‘abnormal’ results reported in our cohort were in children over one year-old who had raised Rubella IgG but normal IgM. Rubella testing in neonates whose mothers are rubella positive at initial antenatal booking will also yield false positives as IgG crosses the placenta.

As TORCH is generally thought of as a single serum test, it has been increasingly used inappropriately.³ The screen itself is made up of many elements and it may be more appropriate to consider targeted testing of components of the TORCH screen on a case by case basis following a detailed maternal antenatal history and taking into consideration the child’s co-morbidities and vaccination status.