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Category : Nethrachikitsa (Ophthalmology)
Timira is one of the grave diseases posing challenge to the eyesight. It disturbes the physiology of visual perception and even terminates in blindness. Many of the clinical features described for timira are having similarities with the refractive errors; hence an attempt has been made to understand the etiopathology of timira in this context.
Curvature Ametropia - Abnormal curvature of the refractive surfaces.
Index Ametropia - Abnormal refractive indices.
Abnormal position of the lens.
In great majority of cases certainly in the higher degrees myopia is axial i.e. due to an increase in the antero-posterior diameter of the eyeball
May be associated with increase in curvature of cornea or one of both surfaces of lens. An increased curvature of the cornea not infrequently occurs but it is usually evident as an astigmatic rather than a spherical error.
INDEX MYOPIA As far as the index myopia is concerned, a change of refractive index of aqueous or vitreous can never be so great as to exercise any appreciable effect. On the other hand, the change in the refractive index of lens can certainly induce myopia.
2. In other cases and in high myopia there is often, in addition, discomfort after near work, due largely to disproportion between the efforts of accommodation and convergence.
3. The eye may be sensitive to light.
1. Black spots may be seen floating before them and some tome flashes of light are noticed; the later may occur irrespective of any tendency to detachment of retina.
2. In very high myopia the eyes are prominent, the pupils are large, the anterior chamber appears deeper than normal, probably only owing to the dilation of the pupil.
3. Vision may be very poor, even with optical correction.
4. There may be an apparent convergent squint.
5. Scotoma may be present, both central and peripheral.
6. In the smaller degrees of error especially, symptoms of eyestrain are evident, although generally, not so obviously as in the cases of hypermetropia.
There is no universally accepted method of preventing myopia. However, some clinicians identify near point vision stress as a possible contributor to the development of simple myopia. When presented with signs of near point vision stress, such as distance blur, poor accommodative facility and refraction at about plano, some clinicians recommend regimens such as the following.
Plus power lenses in simple vision or bifocal form for reading and near work, as indicated by phoria, relative accommodation or other findings. Vision therapy or orthoptics to eliminate deficiencies in accommodation and vergence function.
The treatment of the timira depends upon the stage and dominance of particular dosha. Iin early stage of timira, when the symptoms of the vitiated doshas have just manifested but have not involved the whole eye, these should be treated by snuffs, collyriums and other purification measures should be undertaken .
Patola, karkotaka, karavellaka, brinjal, tarkari, karira fruits, shigru and artagala; all these vegetables cooked with ghrita also promote eyesight.
2. SYSTEMIC MEASURES.
LOCAL MEASURES - These include Tarpana, Putapaka, Seka, Ashchyotana and Anjana 133. However great emphasis has been given to Anjana in the management of diseases afflicting vision as Anjana expells the localised doshas from the eye 134. Anjana is categorised into lekhana, ropana, and prasadana according to their therapeutic efficacy. Various types of anjanas with their processing and particular use are indicated in Sushruta.
Lekhana Anjana is useful when the doshs are situated in siras, srotas, and netra kosha and shringataka region. Ropana Anjana provides varna and Bala to drishti. Prasadana Anjana reduces dryness by supplementing oleation.
Vagbhata has included 4th category called snehana Anjana in which sarpavasa etc. are used to relieve timira.
Later scholars have advocated the use of swarasa and arkas for local use in timira. Lekhana ashchyotana is more useful in eradicating the localised doshas in the netrapatalas.
SYSTEMIC MEASURES - The systemic treatment of timira begins with venepuncture to allay rakta dushti (blood letting) 138. It should be followed by virechana with old ghrita. Virechana is ideal for Anulomana of doshas for which Eranda taila (in vataja timira); Triphala ghrita (in pittaja timira) and Trivrita ghrita (in kaphaja timira) are indicated. Sushruta and others indicate numbers of nasyas in the management of timira.
Triphala is said to be the drug of choice in case of timira with various anupanas (vehicles) according to the involvement of doshas. This drug is said to be chakshushya, rasayana along with deepana, pachana properties. Other chakshushya rasayana compounds came into Ayurvedic literature after 16th century viz. Saptamrit Lauha etc. many mineral and animal drugs e.g. Yashada etc. is termed as chaksushya.
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TIMIRA
Timira is one of the grave diseases posing challenge to the eyesight. It disturbes the physiology of visual perception and even terminates in blindness. Many of the clinical features described for timira are having similarities with the refractive errors; hence an attempt has been made to understand the etiopathology of timira in this context.MYOPIA
Eye is an integrated system of the body, which requires the image of an object to form on the nervous layer or retina. When this condition is there, the refractive state of the eye is said to be emmetropia. In other words, eye is having no refractive error. The condition, in which incident parallel rays of light from an object donot come to a focus upon the light sensitive layer of the retina, is known as ametropia. This may be due to one or more of the following conditions - Axial Ametropia - Abnormal length of the globe.Curvature Ametropia - Abnormal curvature of the refractive surfaces.
Index Ametropia - Abnormal refractive indices.
Abnormal position of the lens.
DEFINITION
“Myopia is that form of refractive error wherein parallel rays of light come to a focus in front of the sentient layer of the retina when the eye is at rest”. The first satisfactory definition of the condition was stated by Kepler in 1611 AD and Plempius in 1672 AD, examined the myopic eye anatomically and attributed the condition to a lengthening of it’s posterior part. Donder (1866 AD) established it’s pathological basis and detailed it’s clinical manifestations.AETIOLOGY
Axial MyopiaIn great majority of cases certainly in the higher degrees myopia is axial i.e. due to an increase in the antero-posterior diameter of the eyeball
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May be associated with increase in curvature of cornea or one of both surfaces of lens. An increased curvature of the cornea not infrequently occurs but it is usually evident as an astigmatic rather than a spherical error.
INDEX MYOPIA As far as the index myopia is concerned, a change of refractive index of aqueous or vitreous can never be so great as to exercise any appreciable effect. On the other hand, the change in the refractive index of lens can certainly induce myopia.
ADJUVANT FACTORS
Certain allied factors may have some influence in its progress. The most important of which is physical debility; even an emmetropic young adult may develop several diopters of myopia after long exhausting illness. It is difficult to evaluate the importance of near work in the etiology but it seems reasonably certain that the influence of close work is secondary and incidental in the etiology of a condition which is essentially predetermined and constitutional and not environmental effect if at all only in so far as it is associated with bad ocular and general hygiene and lack of adequate facilities for normal and healthy development.CLINICAL FEATURES
1. The only symptom in low myopia may be indistinct distant vision.2. In other cases and in high myopia there is often, in addition, discomfort after near work, due largely to disproportion between the efforts of accommodation and convergence.
3. The eye may be sensitive to light.
1. Black spots may be seen floating before them and some tome flashes of light are noticed; the later may occur irrespective of any tendency to detachment of retina.
2. In very high myopia the eyes are prominent, the pupils are large, the anterior chamber appears deeper than normal, probably only owing to the dilation of the pupil.
3. Vision may be very poor, even with optical correction.
4. There may be an apparent convergent squint.
5. Scotoma may be present, both central and peripheral.
6. In the smaller degrees of error especially, symptoms of eyestrain are evident, although generally, not so obviously as in the cases of hypermetropia.
EARLY DETECTION AND PREVENTION
Reduced unaided visual acuity is a possible indication of myopia, particularly when unaided near visual acuity is normal or better than unaided distance acuity. Myopia can be detected by visual acuity testing, retinoscopy, autorefraction or photorefraction during vision screening or clinical examination. The modified clinical technique, one of the most common vision screening test batteries includes visual acuity, ophthalmoscopy, retinoscopy and a cover test. Some screening programs include autorefraction or photorefraction rather than retinoscopy. Patients or their parents should be cautioned that screenings do not substitute for a comprehensive eye and vision examination, visual acuity testing retinoscopy, autorefraction, or photorefraction alone can not distinguish among the types of myopia.There is no universally accepted method of preventing myopia. However, some clinicians identify near point vision stress as a possible contributor to the development of simple myopia. When presented with signs of near point vision stress, such as distance blur, poor accommodative facility and refraction at about plano, some clinicians recommend regimens such as the following.
Plus power lenses in simple vision or bifocal form for reading and near work, as indicated by phoria, relative accommodation or other findings. Vision therapy or orthoptics to eliminate deficiencies in accommodation and vergence function.
MANAGEMENT OF TIMIRA
In brief, the management essentially consists of the avoidancce of aetiological factors; and specifically, in detail, it implies counteracting the increased vata and other doshas.The treatment of the timira depends upon the stage and dominance of particular dosha. Iin early stage of timira, when the symptoms of the vitiated doshas have just manifested but have not involved the whole eye, these should be treated by snuffs, collyriums and other purification measures should be undertaken .
PREVENTIVE MEASURES
The person who is regularly in habit of taking old preserved ghrita, triphala, shatavari, patola, mudga, Amalaki, and yava (barley) has no reason to fear from even the severest form of timira .PROPHYLACTIC MEASURES
Payasa prepared from shatavari or that prepared similarly from Amalaki or else barley meal cooked with sufficient quantity of ghrita and the decoction of triphala are the prophylactic measures to prevent timira .DIETS TO IMPROVE EYESIGHT
The cooked vegetables of Jivanti, Sunishannaka, Tanduliya, good quantity of Vastuka, chilli and madhuka and also the flesh of birds and of wild animals are beneficial for eyesight.Patola, karkotaka, karavellaka, brinjal, tarkari, karira fruits, shigru and artagala; all these vegetables cooked with ghrita also promote eyesight.
CURATIVE MEASURES
1. LOCAL MEASURES.2. SYSTEMIC MEASURES.
LOCAL MEASURES - These include Tarpana, Putapaka, Seka, Ashchyotana and Anjana 133. However great emphasis has been given to Anjana in the management of diseases afflicting vision as Anjana expells the localised doshas from the eye 134. Anjana is categorised into lekhana, ropana, and prasadana according to their therapeutic efficacy. Various types of anjanas with their processing and particular use are indicated in Sushruta.
Lekhana Anjana is useful when the doshs are situated in siras, srotas, and netra kosha and shringataka region. Ropana Anjana provides varna and Bala to drishti. Prasadana Anjana reduces dryness by supplementing oleation.
Vagbhata has included 4th category called snehana Anjana in which sarpavasa etc. are used to relieve timira.
Later scholars have advocated the use of swarasa and arkas for local use in timira. Lekhana ashchyotana is more useful in eradicating the localised doshas in the netrapatalas.
SYSTEMIC MEASURES - The systemic treatment of timira begins with venepuncture to allay rakta dushti (blood letting) 138. It should be followed by virechana with old ghrita. Virechana is ideal for Anulomana of doshas for which Eranda taila (in vataja timira); Triphala ghrita (in pittaja timira) and Trivrita ghrita (in kaphaja timira) are indicated. Sushruta and others indicate numbers of nasyas in the management of timira.
Triphala is said to be the drug of choice in case of timira with various anupanas (vehicles) according to the involvement of doshas. This drug is said to be chakshushya, rasayana along with deepana, pachana properties. Other chakshushya rasayana compounds came into Ayurvedic literature after 16th century viz. Saptamrit Lauha etc. many mineral and animal drugs e.g. Yashada etc. is termed as chaksushya.
PROGNOSIS OF TIMIRA
Timira, which is situated in the first patala and has not produced discolouration, is curable whereas one situated in the second layer and which has become coloured is curable with difficulty. Timira of 3rd patala is said to be reliable only.Newer Articles:
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