B-mode sonographic evaluation of optic nerve sheath diameter and lens thickness in Nigerian adults with glaucoma

OBJECTIVE: This study was done to investigate the effect(s) of glaucoma on the ocular optic nerve sheath diameter and lens thickness using B-mode ultrasonography. MATERIALS AND METHODS: One hundred and twenty study participants were recruited; 60 subjects with glaucoma and 60 age- and sex-matched controls without glaucoma. The optic nerve sheath diameter and lens thickness of both eyes were measured using a linear high frequency transducer with frequency of 6.5–12MHz. RESULTS: The mean optic nerve sheath diameter of the glaucomatous eyes (3.57 ± 0.19mm and 3.59 ± 0.33mm on the right and left, respectively) were significantly thinner than that of controls (4.23 ± 0.34 mm and 4.26 ± 0.30 mm on the right and left, respectively; p < 0.001). There is increased mean lens thickness in the glaucomatous eyes (4.15 ± 0.43mm and 4.18 ± 0.46mm on the right and left, respectively) than in the controls (4.01 ± 0.56mm and 3.99 ± 0.45mm on the right and left, respectively) with a statistically significant difference seen in the left eye (p = 0.024). CONCLUSION: B-mode ultrasound is a reliable tool of assessing the nerve sheath diameter and lens thickness in glaucoma. Optic nerve sheath diameter is reduced in glaucoma