RU153022U1 - OPHTHALMODYNAMOMETER - Google Patents

Abstract

An ophthalmic dynamometer, which is a system of a manometer connected by a flexible tube to a pump and nozzle for compression and decompression of the eyeball, characterized in that an additional pneumatic damper is connected to the system through an air flow regulator.

Description

The proposed utility model relates to ophthalmology and is intended to create a metered pneumocompression and pneumocompression of the eyeball in order to conduct a variety of stress tests that require modeling changes in intraocular pressure.

Currently, all the devices for creating pneumatic compression and pneumatic decompression of the eyeball, used with various types of pressure sensors, have a common drawback: a high noise level feedback system. In this case, noise is understood as spurious pressure changes superimposed on the useful signal, as a rule, having high frequencies and comparable with the useful signal of amplitude.

An analysis of the causes of spurious pressure surges revealed that the vast majority of them are associated with direct mechanical effects on the nozzle for compression and decompression of the eyeball (lens, cylinder, etc.). Most often, regular and irregular parasitic changes in pressure are associated with movements of the researcher’s hand, saccades of the eye, maintaining the mobility of the patient’s head, and intraocular and retrobulbar pulse waves (if they are not the subject of study). An attempt to smooth out pressure surges during measurements exclusively by mathematical methods (a sliding window) leads to a strong distortion of the measured signal, due to the summation of spurious signals, often unidirectional statistically (Fig. 1, top line).

Disproportionately less (but not less intense) pressure surges occur in the measuring channel of the device. These throws are usually associated with the deformation of a flexible system of pneumatic conductors, or with vibration of the sensor or uneven operation of the pump.

(Fig. 1, bottom line) - Comparison of the signal filtering results before and after introducing the pneumatic damper into the ophthalmic dynamometer system The closest analogue of the proposed utility model is the device of the same purpose, which is an ophthalmic dynamometer containing a housing, an interchangeable tip for contacting with the eye, to create a metered dose vacuum-compression eye ophthalmic dynamometer contains a unit located in the housing to create a vacuum and a discharge level controller connected to it. The branch pipe of the rarefaction line is connected at one end to the vacuum generation unit, and two removable tips are mounted on the other end, each of which is made in the form of an eye suction cup connected to a branch pipe on which the clamp is mounted, two branch pipes are connected to the pipe through a connecting tee a rarefaction line, on which, on the one hand, a nozzle is connected through the connecting tee connected to the vacuum level indicator, and on the other, a nozzle with a clamp for quick discharge Niya. To conduct this study, the participation of two researchers is necessary (patent for utility model No. 83907 of June 27, 2009).

The purpose of creating the proposed utility model is to improve the signal quality during manometric pressure measurement in an ophthalmic dynamometer system. The technical result of the proposed device is the ability to more correctly and accurately conduct stress tests when modeling changes in intraocular pressure.

The technical result is achieved by connecting to the system of an ophthalmic dynamometer a pneumatic damper through an air flow regulator.

If parasitic noises in the system part associated with the nozzle for compression and decompression of the eyeball are eliminated, then the residual noise (sporadic irregular noise in the measuring part of the system) will be insignificant with respect to the useful signal. And in the case when the reconstruction of the pressure profile is important for the study, then due to the irregular nature, the residual noise can be filtered using probabilistic smoothing (Fig. 1).

Thanks to the proposed device, it is possible to determine the actual perfusion pressure in the optic nerve head to determine according to the previously proposed formula for calculating the individual norm of intraocular pressure in patients with primary open-angle glaucoma (Shmyreva V.F., Shmeleva O.A. Method for evaluating ocular perfusion in glaucoma. Ophthalmic Journal, 2000, No. 1, pp. 18-20). Using the proposed device allows to predict further stabilization or non-stabilization of glaucoma.

In FIG. 2 shows the design of an ophthalmic dynamometer with an adjustable damper, where

1 - pressure gauge;

2 - a flexible tube;

3 - pump;

4 - nozzle for compression and decompression of the eyeball;

5 - air flow regulator;

6 - pneumatic damper;

7 - eye of the patient.

The device operates as follows (Fig. 1).

The nozzle for compression and decompression of the eyeball (4), the researcher plans the patient's eye (7). By means of a flexible tube (2), a pressure is applied to the nozzle for compression and decompression of the eyeball (4) and to the manometer (1) by a pump (3). By adjusting the air flow regulator (5), the researcher achieves the required amount of pneumatic damper activation (6), opening it until the pressure gauge stops detecting spurious pressure surges. After that, the researcher can proceed with the necessary diagnostic procedures.

Example No. 1.

Patient B., 75 years old. The diagnosis of OI is primary open-angle glaucoma 2A.

Visual acuity: OD = 0.8sf + 1 = 1

OS = 0.9 n \ k.

On local antihypertensive therapy 4 years (B - blockers 2 times a day in both eyes).

Ophthalmotonus: IOP OD = 12 mm. Hg. St, OS = 12 mm. Hg. Art. IOP is compensated.

Optical media are transparent. When conducting additional studies (computer analysis of visual fields), fluctuation of data is necessary to clarify the dynamics of the glaucoma process and the likelihood of progression of glaucoma optical neuropathy (GON).

Under medical mydriasis, the patient underwent ophthalmodynamometry using an ophthalmodynamometer of the proposed design: after preliminary anesthesia, the optical part of the device is installed on the cornea. The researcher localized the area of the optic nerve head and the exit of the central retinal artery. Using vacuum suction, a vacuum was created to a level where the researcher marks the beginning of pulsation of the central retinal artery (CAS), which corresponds to the level of diastolic perfusion pressure. Due to the high risk of complications when fixing the level of systolic perfusion pressure (which corresponds to the beginning of the cessation of pulsation in the CAC), only diastolic perfusion pressure (the most prognostically significant) was recorded. He was mistaken for perfusion pressure (Pperf). At the time of creating a vacuum to the level of diastolic perfusion pressure, pressure surges were recorded in the system, leading to registration of overestimated indicators of diastolic perfusion pressure and complicating the correct assessment of the results. After that, the damper was turned on until the pressure gauge stopped registering pressure surges. The final adjusted values of diastolic perfusion pressure were slightly lower than the initial ones. The inclusion of a damper system allowed us to achieve more accurate operation of the device and to obtain more correct research results.

Earlier, we proposed the coefficient of perfusion pressure (COP), defined as Pperf. / IOP, where Pperf. - pressure measured by an ophthalmic dynamometer; IOP - level of intraocular pressure in a patient.

We also previously calculated the norm of the coefficient of perfusion pressure: with an efficiency equal to or greater than 1.83, a stable stabilization of the glaucoma process was observed, and, conversely, with a decrease in this indicator, the progression of glaucoma was revealed, which required correction of therapy.

Patient B. Pperf OD = 25 mm. Hg. Art., Pperf OS = 10 mm. Hg. Art. Therefore, the efficiency is OD = 25 mm. Hg. Art. / 12 mm. Hg. St = 2.08; OS efficiency = 10 mm. Hg. Art. / 12 mm. Hg. Art. = 0.83.

Conclusion: OD - compensation, stabilization; OS - compensation, not tabilization, which was subsequently confirmed in the process of dynamic observation and required additional conservative vasoactive therapy.

Example No. 2.

Patient I, 63 years old. Glaucoma is not diagnosed.

Visual acuity: OD = 1.0;

OS = 1.0.

Ophthalmotonus: OD = 19 mm. Hg. st

OS = 19 mm. Hg. Art (without antihypertensive regimen)

Optical media are transparent. She asked about clarifying the diagnosis of glaucoma (during the clinical examination, changes were found in the fundus, including in the area of the optic nerve head).

After drug mydriasis, an ophthalmodynamometry procedure was performed, with Pperf OD = 10 mm. Hg. st .; Pperf OS = 10 mm. Hg. Art .. Efficiency OD = 0.53; OS efficiency = 0.53. The survey results were regarded in favor of not compensating for individual ophthalmotonus (with an average statistical rate for the population of up to 21 mm Hg) and not stabilization of the process. With a further in-depth study, the patient was diagnosed with OI - primary open-angle glaucoma 2A. Prescribed treatment (local antihypertensive therapy).

Thus, the use of the proposed device allows you to more accurately assess the state of the glaucoma process.

Claims (1)

An ophthalmic dynamometer, which is a system of a manometer connected by a flexible tube to a pump and nozzle for compression and decompression of the eyeball, characterized in that an additional pneumatic damper is connected to the system through an air flow regulator.

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