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Abstract #13255 Published in IGR 8-1
Relationship between diurnal intraocular pressure variations and blood pressure in glaucoma patients with normal tension glaucoma
Endo YYokohama Medical Journal 2005; 56: 161-165
Normal tension glaucoma is seen in many cases of glaucoma in Japan. Although this type of glaucoma may cause blindness, the mechanism leading to vision loss has yet to be explained. This disease has no effective treatment or prevention. No evidence exists for other risk factors except for intraocular pressure (IOP). Higher IOP and larger variability of IOP are known to be involved in progression. This study investigated whether blood pressure might be a risk factor for progression of normal tension glaucoma. The subjects were 81 patients with untreated normal tension glaucoma, and diurnal variation of intraocular pressure (IOP) and blood pressure were monitored. As for IOP, the period of time to reach the peak and diurnal variation of IOP were identified. The patients were classified by blood pressure: hypertension group (systolic ≥ 140 mmHg or diastolic ≥ 90 mmHg), hypotension group (systolic ≤ 100 mmHg) and normotension group (not applicable for the above two groups), and the time of the day when peak IOP was reached and diurnal variation of IOP were compared among the three groups. The mean diurnal variation of IOP in the 81 patients was 4.9 mmHg. Ten patients (12%) were diagnosed with open-angle glaucoma, not normal tension glaucoma, because they had IOP of ≥ 21 mmHg. Of 51 patients with a peak IOP in the daytime, 35 patients (43.2%) were morning type (9 am-12 noon) and 16 patients (19.8%) were afternoon type (3 pm-6 pm). Twenty-six patients had their peak at night: 5 patients (6.2%) were night type (9 pm-0 am) and 21 patients (25.9%) were after-midnight to early morning type (3 am-6 am). The remaining 4 patients (5%) were regarded as flat type since their diurnal variations were 3 mmHg or lower. Comparing mean diurnal variations among the three blood pressure groups, the hypotension group (6.3 mmHg; n = 15) was significantly larger than the normotension group (4.6 mmHg; n = 10) and the hypertension group (4.4 mmHg; n = 56) (p < 0.05). In conclusion, these results suggest that some patients may be found to have open-angle glaucoma in re-examination even if their IOPs in an outpatient clinic are normal, and that hypotension is potentially a risk factor for progression of normal tension glaucoma because many patients with hypotension show large diurnal variations. LA: Japanese
Dr. Y. Endo, Department of Ophthalmology, Yokohama City University School of Medicine, Japan
Classification:
6.1 Intraocular pressure measurement; factors affecting IOP (Part of: 6 Clinical examination methods)
9.2.4 Normal pressure glaucoma (Part of: 9 Clinical forms of glaucomas > 9.2 Primary open angle glaucomas)
