RU2326582C1 - Method of age-specific cataract diagnostics - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: crystalline lens is laser emitted with wave length within the range 320-350 nm, crystalline lens fluorescence strength is registered by spectrometer in three points at wave length 400, 440, 500 nm. Diagnosis is subject to lenticular opacity index calculated by formula:

where α is lenticular opacity index, I₁ is fluorescence strength at wave length 400 nm, I₂ is fluorescence strength at wave length 440 nm, I₃ is fluorescence strength at wave length 500 nm,

is averaged values of fluorescence strength applicable for transparent crystalline lens at related wave length,

is averaged values of fluorescence strength applicable for cataract crystalline lens at related wave length, and value α - 0.20-0.40 indicates non-altered crystalline lens behavior, value α - 0.41-0.60 indicates phacosclerosis, and values α - 0.61-0.80 indicates initial age-specific cataract, value α - 0.81-0.90 indicates immature age-specific cataract, and value α - 0.91-1.0 indicates mature age-specific cataract.

EFFECT: rapid and high accuracy diagnostics of cataract of various developmental stages that in turn enables to start well-timed medicinal treatment and to provide differential approach to treatment of age-specific cataract of various developmental stages.

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Description

The invention relates to medicine, in particular to ophthalmology, and in particular to methods for diagnosing age-related cataracts.

A known method for diagnosing the development of age-related cataracts (RU 2273024 C2, G01N 33/48, 03/27/2006), including microscopic examination of the lacrimal fluid, which is previously incubated for 10-15 minutes at a temperature of 35-37 ° C, is applied to a defatted glass slide in in the form of a drop, they are dehydrated for 45-60 minutes, and when spotted foreign isotropic inclusions are detected in the marginal zone of the lacrimal fluid sample, the development of age-related cataract is diagnosed.

This method does not allow to diagnose individual stages of cataract development, is not accurate enough, time-consuming.

One of the main methods of studying the lens in Russia at present is slit lamp biomicroscopy, which is based on the phenomenon of light scattering by media with pronounced optical inhomogeneities (Urmacher L.S., Aizenshtat L.I. Ophthalmic devices: Textbook. - M. : Medicine, 1988 .-- 288 p.).

The disadvantage of a method for diagnosing cataracts using a slit lamp is its lack of accuracy - the examined eye area illuminated by a slit lamp is observed under a microscope by a doctor, so a subjective assessment of the state of the lens is not ruled out.

The closest in technical essence to the claimed is a method for measuring the transparency of the lens using a device containing a xenon lamp, an optical system for focusing the radiation of the lamp on the lens and collecting the fluorescence of the lens, a spectrophotometer for recording fluorescence spectra (US Patent No. 4852987, Aug. 1.1989, Int. C1. A61B 3/10, A61B 5/00). According to this invention, it is proposed to record the fluorescence spectra of the lens in the wavelength range from 380 to 600 nm with an excitation wavelength of 350 to 500 nm.

The method (using a known device) is intended only for the diagnosis of nuclear cataracts, it is not applicable for the diagnosis of other cataracts due to the technical characteristics of the device, since with the help of a complex optical guidance system for lighting, the excitation beam is projected only on the central part of the lens without capturing it peripheral areas. In addition, the claimed wavelength parameters for exciting fluorescence of the lens have a fairly wide range. The wavelengths of the claimed range are absorbed not only by the lens, but partially by the cornea and moisture of the eye, which distorts the fluorescence pattern and, as a result, the fluorescence is removed not only from the lens, but also from other tissues of the eye, which reduces the accuracy of the study. The disadvantages of the known solutions include the relative duration of the diagnosis due to registration of the intensity of the fluorescence of the crystalline lens at a significant number of exciting wavelengths. Finally, it is unsafe due to the fact that the filters used in the diagnostic device do not cut off the B-band, that is, there is a radiation load on the eye being examined.

The task of the invention is to increase the degree of accuracy in diagnosing stages of age-related cataract and the exclusion of subjective assessment.

The problem is solved by the fact that the lens is affected by a laser emitter in a wavelength range of 320-350 nm, the fluorescence intensity of the lens is recorded on a spectrometer at three points at wavelengths of 400, 440, 500 nm, the diagnosis is made depending on the turbidity index, which is calculated by the formula:

where a is the lens opacity index,

I ₁ - the fluorescence intensity at a wavelength of 400 nm,

I ₂ - the fluorescence intensity at a wavelength of 440 nm,

I ₃ - the fluorescence intensity at a wavelength of 500 nm,

- усредненные значения интенсивности флуоресценции для людей с прозрачным хрусталиком, на соответствующих длинах волн,

- averaged fluorescence intensities for people with a clear crystalline lens, at appropriate wavelengths,

- усредненные значения интенсивности флуоресценции для людей с катарактальным хрусталиком, на соответствующих длинах волн, и при значениях α - 0,20-0,40 диагностируют отсутствие изменений хрусталика, при α - 0,41-0,60 - факосклероз, при α - 0,61-0,80 - начальную возрастную катаракту, при α - 0,81-0,90 - незрелую возрастную катаракту, при α - 0,91-1,0 - зрелую возрастную катаракту.

- the average values of fluorescence intensity for people with a cataract lens, at the appropriate wavelengths, and for values of α - 0.20-0.40, diagnose the absence of changes in the lens, with α - 0.41-0.60 - phacosclerosis, with α - 0 , 61-0.80 - initial age-related cataract, with α - 0.81-0.90 - immature age-related cataract, with α - 0.91-1.0 - mature age-related cataract.

Distinctive features of the invention are:

- exposure to the lens with a laser emitter of a wavelength range of 320-350 nm, which ensures maximum excitation of the fluorescence of the lens and does not affect other environments of the eye;

- registration of fluorescence intensity at three points at wavelengths of 400, 440, 500 nm and determination of the stage of development of age-related cataracts by the lens opacity index, calculated by us, by the formula:

- allows you to quickly and with a high degree of accuracy to diagnose cataracts and determine the stages of its development.

Diagnosis of age-related cataract is as follows. The lens of the patient’s eye is affected by exciting radiation with a wavelength range of 320-350 nm. The use of ultraviolet radiation with a wavelength range of 320-350 nm is justified by the fact that it is the radiation of this range that is absorbed by the lens as much as possible and not absorbed by other environments of the eye, such as the cornea and eye moisture, and does not cause damage to eye tissues. The native fluorescence of the lens is recorded at three empirically calculated points with wavelengths of 400, 440 and 500 nm, two of which 400 and 500 nm are isobestic, and 440 nm is the wavelength at which the fluorescence spectra of the lens of healthy and cataract patients, have a maximum deviation amplitude. The diagnosis is made depending on the value of the turbidity index, which is calculated by the formula (I):

where α is the lens opacity index,

I ₁ - the fluorescence intensity at a wavelength of 400 nm,

I ₂ - the fluorescence intensity at a wavelength of 440 nm,

I ₃ - the fluorescence intensity at a wavelength of 500 nm,

- усредненные значения интенсивности флюоресценции для людей с прозрачным хрусталиком, на соответствующих длинах волн,

- averaged fluorescence intensities for people with a clear crystalline lens, at appropriate wavelengths,

- усредненные значения интенсивности флюоресценции для людей с катарактальным хрусталиком, на соответствующих длинах волн. Полученное значение индекса помутнения хрусталика α сопоставляют с интервалами значений степени помутнения хрусталика на разных стадиях развития катаракты: при значениях α - 0,20-0,40 диагностируют отсутствие изменений хрусталика, при α - 0,41-0,60 - факосклероз, при α - 0,61-0,80 - начальную возрастную катаракту, при α - 0,81-0,90 - незрелую возрастную катаракту, при α - 0,91-1,0 - зрелую возрастную катаракту.

- average values of fluorescence intensity for people with a cataract lens, at the corresponding wavelengths. The obtained value of the lens opacity index α is compared with the intervals of the degree of opacification of the lens at different stages of cataract development: at values of α - 0.20-0.40, the absence of lens changes is diagnosed, at α - 0.41-0.60 - phacosclerosis, at α - 0.61-0.80 - initial age-related cataract, with α - 0.81-0.90 - immature age-related cataract, with α - 0.91-1.0 - mature age-related cataract.

Three groups of people were examined: the first group (38 people) included healthy people, without visual impairment up to 25 years old, the second group (27 people) included healthy people, without visual impairment after 25 years (with a formed nucleus lens - phacosclerosis), in the 3rd group (69 people) - patients with age-related cataracts of varying degrees of maturity. All people were examined on a slit lamp in an ophthalmic clinic, and a diagnosis was made. After that, the diagnosis of both eyes was additionally carried out by the claimed method. The lens of the patient’s eye was exposed to exciting radiation with a wavelength range of 320-350 nm. The intrinsic lens fluorescence was recorded on a spectrometer at three points with wavelengths of 400, 440 and 500 nm. For each eye, the lens opacity index α was calculated using formula (1). The obtained value of the lens opacity index α was compared with the previously diagnosed: at values of α - 0.20-0.40, the absence of changes in the lens is diagnosed, at α - 0.41-0.60 - phacosclerosis, at α - 0.61-0, 80 - initial age-related cataract, with α - 0.81-0.90 - phacosclerosis, with α - 0.61-0.80 - initial age-related cataract, with α - 0.81-0.90 - immature age-related cataract, with α - 0.91-1.0 - mature age-related cataract. Of greatest interest was the third group of people. We made a comparative description of the diagnoses made by two different eye examinations: slit lamp biomicroscopy and diagnostics of the claimed method.

The table shows a comparative characteristic of two eye examinations: biomicroscopy on a slit lamp and diagnosis of the claimed method.

The diagnosis made by a doctor with biomicroscopy on a slit lamp without additional diagnostic methods (69 people - 138 eyes) Diagnostics of the claimed method Initial age-related cataract - 45 eyes Of the 45 eyes examined on a slit lamp, 29 eyes had an initial age-related cataract; 16 - immature age-related cataract. Immature age-related cataract - 52 eyes Of the 52 eyes examined on a slit lamp, 13 eyes had an initial age-related cataract; 32 - immature age-related cataract; 7 - mature age-related cataract. Mature age-related cataract - 41 eyes Of the 41 eyes examined on a slit lamp, 32 eyes had a mature age-related cataract; 9 - immature age-related cataract

Then, the subjects underwent a more complete ophthalmological examination, which confirmed the diagnosis made by our claimed method.

A method for diagnosing stages of age-related cataract is illustrated by the following examples.

Example 1

Patient V., 59 years old, complaints of decreased vision in both eyes, more than the right eye. Somatically healthy, no hereditary diseases. With biomicroscopy on a slit lamp, the doctor diagnosed: initial age-related cataracts of both eyes. Diagnosis of the cataract stage of both eyes by the claimed method showed the following results: right eye — turbidity index (α) - 0.82; left eye - turbidity index (α) - 0.68, i.e. diagnosis; immature age-related cataract of the right eye, initial age-related cataract of the left eye.

In the above example, a diagnostic examination of the patient’s eye lens using the proposed method, allowed to detect the presence of an immature age-related cataract of the right eye, and confirmed the presence of an initial age-related cataract of the left eye, while with biomicroscopy on a slit lamp, the doctor diagnosed an initial age-related cataract of both eyes, but this assessment subjective. Diagnosis of the cataract stage by the claimed method completely eliminates the subjective assessment factor, accurately establishes the diagnosis by the lens opacity index.

Example 2

Patient V., 63 years old. As a result of a professional examination with a standard ophthalmological examination: Vis OD = 0.8 (-) 0.5D = 1.0; OS = 1.0. Otherwise, no pathology was detected. Diagnosis of the cataract stage of both eyes by the claimed method showed the following results OD - α = 0.62; OS - α = 0.55. That is, as a result of examining the lens of the eye with a fluorescent method, the initial age-related cataract of the right eye and the stage of phacosclerosis of the left eye were revealed, which was not diagnosed by previous ophthalmological studies.

Thus, the proposed method for the diagnosis of age-related cataracts allows you to quickly and with a high degree of accuracy to diagnose cataracts at different stages of development, which in turn will allow you to start timely medication and provide a differentiated approach to the treatment of patients with age-related cataracts at different stages of development.

Claims (1)

A method for diagnosing age-related cataracts, including exposure to the lens with exciting radiation and diagnostics to determine the fluorescence intensity, characterized in that the lens is affected by a laser emitter with a wavelength of 320-350 nm, the lens fluorescence intensity is recorded on a spectrometer at three points at wavelengths 400, 440 , 500 nm, the diagnosis is made depending on the value of the turbidity index, which is calculated by the formula

where α is the lens opacity index; I ₁ - fluorescence intensity at a wavelength of 400 nm; I ₂ - the fluorescence intensity at a wavelength of 440 nm; I ₃ - fluorescence intensity at a wavelength of 500 nm;

- averaged fluorescence intensities for people with a clear crystalline lens, at appropriate wavelengths,

- the average values of fluorescence intensity for people with a cataract lens, at the appropriate wavelengths, and for values of α - 0.20-0.40, diagnose the absence of changes in the lens, with α - 0.41-0.60 - phacosclerosis, with α - 0 , 61-0.80 - initial age-related cataract, with α - 0.81-0.90 - immature age-related cataract, with α - 0.91-1.0 - mature age-related cataract.