Page 52 - Clinical variability in Noonan syndrome with emphasison ear and eye
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CHAPTER 3
ABC
Figure 1. External ocular manifestations of Noonan syndrome (NS).
A, left column: Examples of ptosis asymmetry; note the difference between the right eye and the left eye (Patients 2, 12, and 15). B, middle column: Examples of lower eyelid retraction; note inferior scleral show in the primary position of gaze (Patients 6, 9, and 13). C, right column: Examples of upward slanting palpebral fissures; note that abnormal slanting palpebral fissures in NS are not always downward (Patients 4, 16, and 18). Photographs were taken under standardized conditions, with permission for publication.
One patient (Patient 7), who showed normal ocular alignment at distance and near (30 cm), did not exhibit stereopsis with reading because of V-pattern esotropia with suppression in downgaze. Nystagmus was found in two patients (8%); one of them (Patient 19) had poor vision and infantile sensory nystagmus.
Anterior segment
Ophthalmologic examination with slit-lamp biomicroscopy (Table 2, category 4) showed two corneal features: prominent corneal nerves (Figure 3) in 18 patients (72%) and posterior embryotoxon (anteriorly displaced Schwalbe line at the corneal limbus) (Figure 4) in eight patients (32%). The number of clearly visible corneal nerves varied between only one pair to more than 20 visible nerves in both eyes. In two patients (Patient 6 and Patient 23, Table 1) an asymmetric number of visible nerves between the two eyes was found. The posterior embryotoxon was located temporally in four patients and both temporally and nasally in the other four patients. There were no other abnormalities discovered with slit-lamp examination.
Posterior segment
Ocular examinations in the categories 5 and 6 (Table 2), showed additional ocular features with a prevalence of less than 25%: non-glaucomatous optic disc excavation (cup-to-disc ratio of 0.5 or more) in five patients (20%) and bilateral optic nerve hypoplasia in one patient (4%) (Figure 5). Two patients (8%) showed tortuous retinal vessels. No other relevant ophthalmoscopic features were found.
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