Up-to-Date Medical Care System for Glaucoma
I. Customized glaucoma treatment
1. Diurnal variations of intraocular pressure (IOP)
IOP levels vary throughout the day, and each individual has a definite pattern. The IOP value is thought to change with a sign curve over a 24-hour period. Even if the value is in the normal range when it is measured at a specific time point during a day, the value may exceed the normal limit at other times in a day. Therefore, consecutive measurement of the diurnal variations of IOP over 24 hours is important for a precise diagnosis is especially for normal tension glaucoma, which has been receiving a great deal of attention recently. At present only a few institutions in the world perform this examination routinely outside the boundaries of a research experiment due to the following 2 reasons. 1. Difficult to prepare beds for the purpose. 2. Difficult to keep staff member to perform a 24-hour consecutive measurement. Hara Eye Hospital can provide this examination. At present, the IOP value is measured with the patient in the sitting position, which is the same as the standard medical examination worldwide. However, in some patients the IOP may increase considerably when the patients is at supine position, as when taking a nap or sleeping at night, based on the position of the eye relative to the heart. To ascertain if this is the case in individual patients, physicians at the Hara Eye Hospital measure IOP values with the patients sitting and supine over a 24-hour period. And, although this examination is generally referred to as 24-hour diurnal variation measurement, in actuality the values are measured over 26 hours, because the IOP values should be measured twice at the same time, for example, at 10 o'clock on the first day and again at the same time the following day. With the results of this examination, precise medical treatment can be adjusted to the IOP variation with the goal of flattening the peak of the diurnal change. We consider this to be customized treatment of glaucoma, that is, treatment that fits the individual. The examination is initially performed with the patient not taking glaucoma medication, which will help further evaluate the efficacy of the medications by allowing the physicians to compare the IOP values with and without medication. For this reason, a patient may be asked to stop taking his or her drug in case the glaucoma is in the early stage of development. Measuring diurnal variations in IOP is also possible on weekends or national holidays. For example, a patient who starts the IOP measurement on Saturday afternoon can leave hospital on Sunday afternoon. This 2-day hospitalization (including all hospital expenses) is covered by Japanese health insurance if the patient join this system.
2. Methods of glaucoma examination
Patients can undergo various up-to-date examinations at Hara Eye Hospital.
(1) IOP examination (tonometry)
Goldmann applanation tonometry Tonometry by noncontact pneumatic tonometry, which prevents the development of in-hospital infections
(2) Visual field examination
Goldmann peripheral perimetry
Humphrey static campimetry
Aulhorn static cross-section campimetry
(3) Quantitative optic fundus analysis
It is possible to objectively evaluate long-term changes by quantitatively measuring the unhealthy pit condition of the optic disc, which is an important glaucomatous finding with the latest computer analyzing system (HRT, Heiderberg retinal tomography).
(4) Various measurements of the anterior chamber angle
(5) Tonography
Quantitative measurement of the volume of aqueous humor drainage, which moves in and out of the eye.