Page 164 - Demo

Chapter 5162Another common finding in 22q11.2DS was posterior embryotoxon (22-50%), that also has a higher prevalence compared to the general population (7%).46 As proposed by others, posterior embryotoxon and other anterior segment abnormalities may be a result of defects in migration, proliferation and differentiation of neural crest cells in an early embryologic stage in 22q11.2DS.7, 9, 47 Anterior segment dysgenesis may increase the risk of glaucoma, which was reported only once in the included review studies9and in not a single patient in our cohort. Other findings supporting a role of a 22q11.2 deletion in anterior segment dysgenesis were scarce, including Peter’s anomaly, iris remnants and lens opacities.7, 9With advances in clinical genetic testing, ophthalmic screening is no longer important for diagnosing 22q11.2DS. Another reason for screening after birth could be an increased prevalence of congenital cataract because of its impact on the development of the visual system. However, based on our results, we cannot conclude that congenital cataract has a higher prevalence in 22q11.2DS compared to the general population.Table 4. Recommendations for ophthalmic and orthoptic screening in 22q11.2DS.Assessment At diagnosis At three years old At adulthoodStrabismus √ √Amblyopia √ √Refractive errors √ √ Low-threshold Visual acuity √ √ Low-thresholdEach √ refers to a single assessment with follow-up as needed. Ophthalmic screening should bedone at least once by an ophthalmologist.We would recommend that children with 22q11.2DS receive screening by an ophthalmologist and orthoptist at the age of three years in order to detect and treat strabismus, amblyopia and refractive errors, which have high prevalence rates in 22q11.2DS. From the age of three years a reliable monocular VA measurement should be possible. Also, detection of amblyopia is important at an early age because of reduced plasticity of the visual cortex after the age of 7 years. Patients diagnosed with 22q11.2DS after the age of three years should receive ophthalmic and orthoptic screening at diagnosis with follow-up as needed.