Prevalence of glaucoma and characteristics of ocular manifestations in patients with Naevus of Ota

Aims This cross-sectional study aimed to determine the prevalence of glaucoma and associated ocular characteristics in Thai patients with Naevus of Ota, comparing those with ocular melanocytosis or oculodermal melanocytosis to those exhibiting only skin hyperpigmentation. Methods Patients who were diagnosed with Naevus of Ota at Siriraj Hospital, Thailand, underwent a comprehensive ophthalmic assessment by a glaucoma specialist. Those unable to cooperate in an outpatient setting were examined under general anaesthesia. The assessments comprised visual acuity, intraocular pressure (IOP), anterior segment findings, gonioscopy, corneal diameter (in patients aged <3 years) and fundus examination. Visual field and optical coherence tomography tests were performed as indicated. Results A total of 163 patients (184 eyes) were examined, including 115 eyes with ocular melanocytosis or oculodermal melanocytosis. The mean age at examination was 15.0±15.6 years. Open-angle glaucoma was identified in 2 eyes (1.1%), ocular hypertension in 6 eyes (3.3%) and glaucoma suspicion in 16 eyes (8.7%). Among those with ocular melanocytosis or oculodermal melanocytosis, ocular hypertension and glaucoma suspicion were more common (4.3% and 12.2%, respectively) than in those with only skin hyperpigmentation (1.4% and 2.9%, respectively). Conclusion Although the prevalence of glaucoma in Naevus of Ota is low, patients with ocular melanocytosis or oculodermal melanocytosis are at greater risk of ocular hypertension and suspected glaucoma than are those with skin-only hyperpigmentation. Targeted screening, particularly in younger individuals and those requiring examination under general anaesthesia, should be considered. The main limitation of the study is its cross-sectional design, offering only a one-time view of a prolonged clinical progression. Moreover, the use of anaesthetic inhalation could have resulted in lower IOP readings during general anaesthesia. Trial registration number TCTR20210223004.