|Year : 1958 | Volume
| Issue : 3 | Page : 41-48
Iontotherapy in ophthalmology
K. B. Haji Bachooali Free Ophthalmic Hospital, Parel, Bombay, India
|Date of Web Publication||8-May-2008|
B D Telang
K. B. Haji Bachooali Free Ophthalmic Hospital, Parel, Bombay
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Telang B D. Iontotherapy in ophthalmology. Indian J Ophthalmol 1958;6:41-8
Iontotherapy in Ophthalmology is far from being a new form of treatment. It has been employed in general medicine for over a hundred years and in the treatment of ocular diseases for more than fifty years. The old methods were laborious and results not encouraging, because of too strong a current, too strong solutions and too long applications.
Iontotherapy accelerates treatment by ions electrically administered. Iontophoresis also increases penetration of ionised drugs by (I) driving the ions of the same charge as the electrode into the eye and (2) by increasing the permeability of the corneal epithelium regardless of which electrode is placed on the cornea.
The pharmaco-dynamic effect of the current plus the electrolyte consists in a sudden alteration as in the permeability of the tissues and with it also the surface tension. The electrolytes are fixed somewhat longer to the cells. We are able to stimulate sympathetic and para-sympathetic nerves with this method in a better way and we may influence the circulation in a sense which is favourable to the restoration of normal or nearly normal functions. With this method, we can direct the desired substances in sufficient quantity to the site of the lesion.
The treatment of ocular diseases by Iontophoresis has assumed increased importance with the advent of chemotherapy and the antibiotics. The usefulness of Iontophoresis is based on the fact that like charges repel one another, and that electrolytes administered by this method may reach higher tissue concentrations than by any other method. The method is especially useful in ophthalmic use because of the small area to be treated.
When using Iontophoresis the pole applied to the eye is of utmost importance. When the active principle of the drug is present in the cation, iontophoresis should be from the anode. Reversal of the polarity results in levels similar to those obtained by corneal bath.
| Apparatus Required|| |
The essential apparatus necessary for ocular Iontophoresis includes a source of galvanic current and some type of active electrode which will keep the therapeutic solution in contact with the cornea. I have been using the apparatus prepared by Hamblin. The apparatus with the dry batteries is contained in a case measuring 8 x 6 x 3½ in. the sloping front panel of which carries a dual purpose meter and the controls. The meter is calibrated to record on the lower scale the voltage of the battery and this can be readily checked by pressing a test button which connects the meter as a volt-meter. Situated centrally below the meter, is an out-put control rheostat combined into an on/off switch. Switching on by a clock-wise movement brings into operation the meter as a 5-10 milliamperes out-put meter. The instrument is so constructed that positive ions, such as calcium and zinc are normally introduced into the eye and is provided with a reversing switch for introducing negative ions such as salicylates. The hand and treatment electrodes with their flexible leads and plug connections complete the apparatus. The hand electrode has advantage over the usual flat leadfoil electrodes applied to the nape of the neck and other parts of the body in that there is no burning sensation at the place of contact with the skin. It avoids electrical stimulation of brain, sometimes evidenced by headache and vertigo, which may follow iontophoresis when one electrode is applied to the eye and the other to the nape of the neck. The rod-type hand electrode is held by both hands of the patient and serves as the indifferent electrode. The active electrode consists of straight metal rod with serrations at the tip to hold the cotton swab moistened in the required drug solution. Two types of active electrodes made of "Lucite" are also described. One of these has a contact lens base with a narrow chimney extending from its centre which serves as a reservoir for the solution. Inside is a platinum loop which acts as an active. electrode and is in contact with the solution as well as to the source of the current. The other applicator consists of an eye-cup made of plastic. Eye applicators made of glass have beer described also. (Fleming 1953).
Identical results were obtained when the eye electrode was buried in cotton placed over the eye and soaked with the test solution with those obtained by means of the plastic eye-cup electrode.
| Theory of Iontophoresis|| |
Some of the molecules of salts, acids and bases, when dissolved in water undergo dissociation into positively charged ions and negatively charged ions. The less concentrated the solution the more molecules become dissociated into ions. An electric current can be made to pass through this solution by introducing into it the positive poles and the negative poles of the battery. A flow of current between these two poles occurs by virtue of the ionised substances which themselves serve as the conductors of the electrons. [Figure - 2]
The electro-positive ions are called 'cations' because they are directed to the negative pole or cathode during electrolysis and similarly the electronegative ions, called 'anions' are directed to the positive pole or anode. It is thus seen that the two kinds of ions are designated by the poles to which they are attracted rather than by the electric charge which they carry. When the electric current of a battery is turned on, one electrode receives a positive charge the other receives negative charge. The direction of the flow of the current is from the positive (anode) towards the negative pole - (cathode). If the current passes through an electrolyte (i.e. through an aqueous solution of substances that conduct electricity) the electro-positive ions or cations travel towards the negative poles or cathode. The anions or electro-negative ions are attracted towards the positive poles or anode. Hence like charges repel and unlike charges attract. - Selinger, (1947).
Since the human body is a good conductor of electricity these same principles may be applied to accomplish therapeutic ion transfer. In order to drive the proper ion into the tissues, one should know whether one wants to carry the ions with positive or with the negative electric charge into the tissues. The electrodes are then arranged in such a way that the flow of the current is through the tissues of the eye towards the indifferent electrode held in the hand. This means that the eye electrode is connected to the positive or to the negative pole depending on the substances used for iontophoresis, - Smith, (1951). Thus when atropine sulphate is used for iontophoresis, the purpose is to have electro positive atropine ions go through the cornea towards the indifferent hand electrode. The active electrode is positively charged, the positively charged atropine ions will then be repelled from the eye electrode (anode) and attracted towards the negative indifferent electrode. Thus the atropine ions pass through the cornea into the aqueous.
If sodium penicillin solution is used, the electrodes, must be reversed in charge since here it is the negatively charged ions (Penicillin) which is of therapeutic value and can only be introduced into the eye by assigning to the active electrode a like charge. The active electrode must then be the negative (Cathode) while the indifferent electrode is positive (anode). In other words, in order to cause electro-positive ions to enter the eye, the eye electrode must be connected with the positive pole. For electro-negative ion transfer, the eye electrode is connected with the negative pole. This arrangement of the electrode permits the proper ions to pass through the eye towards the opposite (hand) electrode to which they are attracted.
| Technique of Iontophoresis|| |
It is satisfactory to have the patient lying supine on the table. Some authors suggest that no local anaesthetic is necessary, but it has been shown that their use increases the permeability of the cornea as well as adds to the comforts of the patient. Anethaine 0.5% solution is satisfactory.
The source of current is made ready but is not turned on until all the preparations have been made. The hand electrode is grasped firmly into both hands by the patient. The patient's face is directed towards the ceiling keeping both eyes open. The lids are separated and the applicator is inserted between the lids. The lids are then released. The patient is instructed to keep both eyes open and to look straight up, throughout the treatment. In some cases, it may be helpful to insert a lid speculum before introducing the contact electrode.
Having previously selected the proper charge to be used at the active electrode, the ampmeter is set at '0' and the switch turned on. No current will flow until the rheostat knob is turned slowly until a current of 1.5 to 2.00 ma. is registered on the ampmeter. One should not go beyond 2 ma. If the battery should be low, the current can be stepped up by placing a piece of cotton moistened in salt solution or in tap water (distilled water is a non-conductor), over the hand electrode. At the conclusion of the treatment, the current is reduced slowly till the ampmeter is returned to '0' and the switch turned off before any break is made in the circuit. This eliminates any current shock which might alarm the patient. The period of treatment should not exceed 2 to 5 minutes. The treatment may be repeated daily or every second day for four to ten applications.
Occasionally, a slight clouding of the cornea may develop after ionotophoresis. This normally clears up within a few hours. No bandage or medication is necessary after treatment unless indicated by the underlying pathologic process.
After application, the corneal applicator should be sterilised in aqueous merthiolate solution by immersion for twenty minutes.
| Solutions for Iontophoresis|| |
Drugs have been classified so as to indicate the polarity of active electrode. (See Table below).
| Iontophoresis in Ophthalmic Therapy|| |
Iontotherapy may be applied directly to the cornea or to the bulbar conjunctiva, to the closed or everted lids, according to indications. Palpebral iontophoresis gives much less concentration than does corneal iontophoresis. This form of treatment offers a unique assistance to all sorts of ophthalmic conditions.
It must be clearly mentioned that iontotherapy is recommended as an addition to our armamentorium and in no way replaces the crux of the satisfactory treatment of all secondary inflammations. Iontophoresis increases the penetration of penicillin and streptomycin but does not materially increase the penetration of aureomycin.. The anti-biotics are used in the same concentration as is recommended for topical administrations. It is generally agreed that the systemic administration of penicillin results in very low intraocular concentrations. The superiority of penicillin Iontophoresis over its application by corneal baths or sub-conjunctival injections has been demonstrated by von Salmann (1945). He also showed that iontophoresis can produce concentration of penicillin in human eves that are found to be twenty times that produced by corneal baths.
Very satisfactory intra-ocular concentration of streptomycin, dihydrostreptomycin and neomycin have been obtained by iontophoresis. In conical ulcers and uveitis encouraging results are obtained after streptomycin iontophoresis using concentrations of 50 to 100 mg. per c.c. applied over the partially closed lids by a pad saturated with the solution. - Locke, (1949). This comparatively high concentration is necessary because of the dilution by the tears.
Iontophoresis has no advantage over other methods with the anti-biotics which do not ionize in solution (tetracyclines, chloromycetin and bacitracin) or which do not penetrate by other methods (polymyxin)--Witzel, (1956).
As regards Sulfonamides, Boyd, (1942) has shown that administration of sodium sulfathiazole by iontophoresis caused 3 to 10 times greater concentration into the cornea, aqueous and vitreous than did the conical baths. A further advantage of iontophoresis over the systemic administration of sulfathiazole is the absence of toxic reaction often seen following oral use of sulfonamide. This therapy causes rapid healing in trachoma.
Sulfacetamide combined with Penicillin can be administered effectively by iontophoresis without diminishing the potency of either. Thus those organisms susceptible to only one of the agents would be immediately brought under control and much time saved.
In Chronic Conjunctivitis. Where no cause can be found iontophoresis brings about considerable betterment.
Calcium adrenaline solution gives good relief of photophobia and other subjective symptoms in patients with spring catarrah .
In asthenopia with irritability, photo phobia and blepharospasm, where routine measures have disappointing results, iontotherapy with zinc sulphate causes amelioration of symptoms.
The chances for successful treatment by iontophoresis of infected cornea are definitely better to-day since the advent of anti-biotics and sulfonamides.
In active stage of many conical ulcers and serpiginous ulcers, iontophoretic treatment with Penicillin is a definitely superior method. Penicillin in a concentration of 1000 to 2,000 units is applied to the eye for 3 to 5 minutes period once or twice daily. During the recovery from an ulcer, iontotherapy will expedite resolution and reduce residual scarring. It may even prevent it altogether. Infiltrations can be reduced. Pain is alleviated; the filling up of a crater is assisted and expedited, vascularisation is reduced, friable scars may be made strong. This form of treatment is of special value after perforation of the cornea.
Adrenaline in combination with zinc sulphate and calcium chloride has been used by Erlanger (1954) in the treatment of acute infections of the cornea. He advises beginning treatment with zinc adrenaline iontophoresis for 2 or 3 treatments and then using calcium with a adrenaline solution.
II cases of hypopyon ulcers - 8 pneumococcal and 3 streptococcal, were treated with Penicillin iontophoresis daily for 4 minutes. 7 were cured after 5 daily sittings and 4 showed improvement.
Two cases of pyogenic ulcer were cured with 6 sittings of streptomycin for 3 minutes daily.
32 cases of superficial corneal infiltrations were cured with 5 sittings of 3 minutes each of Sodium Sulfacetamide 5% and Cortisone given on alternate days.
Two cases of interstitial keratitis showed marked improvement after 7 sittings of four minutes duration of Cortisone iontophoresis on alternate days.
The analgesic and decongestive effect of iontotherapy are well seen in the treatment of Herpes Ophthalmicus.
In corneal transplantation not successfully performed an attempt should be made with Iontophoretic treatment of the Cornea with Choline chloride 1% from the positive pole. Hydrocortisone instillation should be done after iontophoresis.
The treatment of corneal opacities is very unpromising but it is of interest to note that the treatment by Ionic medication with quinine chloride and cortisone acetate brings about surprising improvement in many cases. Usually the more recent the case the greater the improvement.
58 cases were treated with quinine and cortisone iontophoresis for ten to fifteen sittings of four minutes each on alternate days. Of these 16 had opacity in the deeper layers. In those having moving body to finger counting vision at 1 foot showed no improvement in vision. Those having vision of counting fingers at 4 to 6 feet showed improvement upto counting fingers at 10 to 16 feet. 42 cases having affections in a superficial layer of the cornea showed a more satisfactory improvement.
The treatment of Iritis and Iridocyclitis by Iontophoresis have been satisfactory. In iritis one endeavours to treat the cause and the local congestion with its consequences. The cause is all important but both before and after that has been dealt with, iontotherapy with calcium-adrenaline will help to relieve pain, reduce congestion and avoid complications. For residual, chronic and recurrent iritis, this ionic medication is of greater value. The eye opens up, congestion is relieved and posterior synechiae may be broken clown. Epinephrine can be applied to the cornea at different sectors round the limbus. Its iontophoretic attachment to the cells of the iris makes the instillation of atropine and Cortisone more effective than the mere instillation of the drugs. Calcium adrenaline iontophoresis is the strongest remedy causing the dilatation of the pupil of the eye and disruption of posterior synechia of the pupil. Similarly, atropine iontophoresis may often break the posterior Eynechia when all other methods have failed. There are few conditions more distressing to the patient and an ophthalmic surgeon than iridocyclitis but a greater reward awaits those who give to iontotherapy its due place in the treatment.
Eleven cases of iritis of unknown origin were treated. Two early cases were cured by two sittings of atropine and Cortisone ionisation. Out of the remaining 9 chronic cases , in 7 synechiae were broken and the eyes became uiet after seven sittings of three minutes duration, of atropine, adrenaline and cortisone on alternate days. In the remaining 2 cases, there was slight improvement.
From experience with treatment of iritis and iridocyclitis we feel that secondary glaucoma after uveitis should respond to calcium-epinephrine iontophoresis. This treatment permits removal of the inflammatory products by a combined treatment, first by introduction of calcium and epinephrine by local iontophoresis around the limbus and then by iontophoresis with calcium epinephrine for 10 minutes at 1 ma. strength over the closed lids.
As an aid to the treatment of primary glaucoma and chronic glaucoma iontophoretic introduction of methacholine into the anterior chamber has been recommended by Swan (1953).
In episcleritis and scleritis, where success is more difficult, iontotherapy produces marked and more immediate improvement. Persistence or a recurrence points to an underlying cause which needs treatment.
In post-herpetic neuralgia iontophoresis with novocaine. hydrochloride 2% solution applied over the affected skin by a pad saturated with the solution for 3 to 4 minutes on alternate days has given good relief.
Paresis of Extraocular Muscles
Iontophoresis has been used with success in paralysis of external muscles and also in oculomotor paralysis. Function of the muscle is restored in a relatively short period of 2 weeks. Acetylcholine 1 : 300 is introduced into the paralysed muscles directly for 1 minute at 1 ma. strength. Eserine is used over the closed eyes for 15 minutes at 1 ma. strength.
In five cases of external rectus palsy, one case improved after six sittings of three minutes duration of acetyl-choline on alternate days. Four cases showed marked improvement after 9 sittings.
In two cases of III nerve palsy, no improvement was noticed after 10 sittings on alternate days.
Strabismus cases have been treated by introducing acetyl-choline and choline into the weaker muscle of the eye. Choline serves as an adjuvant to increase the effect of acetyl-choline on the muscle because it probably has an effect on the permeability of the thin am] delicate muscle fibres. (Adler, 1953).
The question of treatment of the posterior part of the eye ball is likely to be more controversial than that of the anterior but it has been shown that these parts are also readily influenced by ionic medications.
The posterior parts of the eye-ball are influenced by ionic medications with vasodilators. These improvements are due to a temporary improvement in circulation.
In many cases of amblyopic eyes with convergent squint, good and lasting results have been achieved, with iontophoresis of Eserine Salicylate (0.015 : 500), applied for as long as 15 to 20 minutes from the positive pole at I ma. Afterwards acetyl-choline is introduced into the weaker muscle of the eye for one minute at 1 ma. strength. It was found that this combined treatment led to quick improvement of the central vision. Best results were achieved by giving this treatment twice a day for several days in succession. Exercises on the amblyoscope may be tried after several treatments.
In retrobulbar neuritis of long standing the disappearance of central scotoma is a further evidence of the 'efficacy of iontophoretic stimulation with vasodilators. The effect of iontophoresis can be enhanced if some of the vasodilator drugs are given orally or by injection at the same time .- Bietti (1952).
Iontophoresis as a Diagnostic and Prognostic Appliance in Ophthalmology
By applying a combined solution of calcium chloride (1.5 : 500) and Eserine Salicylate (0.015 : 500) at a strength of 1 ma. for 15 minutes from the positive pole (eye cup electrode) a clearing of clouded vitreous can be obtained so that a diagnosis can be ma de which before iontophoresis was impossible. The dense opacity consisting of cells, cholesterine crystals and hemorrhages in the vitreous disperses. Thus cases of detachment of retina and choroiditis can be diagnosed within an hour.
This can be explained when we think of the possible charging of these cells in the applied electric field so that they propel each other, separate and let optical beams go through.
Besides, after the 15 minutes procedure, a prognosis concerning the improvement of the vision can be made. Improvement permits a prognosis as to further improvement with the therapeutic process in certain diseases of the posterior part of the eye. In changes, and diseases not responding with an improvement of vision, therapeutic treatment is of doubtful value.
An explanation of many of the striking phenomena occurring through the meticulously applied method of iontophoresis either to a localised pathological process in the cornea or sclera or to the whole organ is rather complicated. But the study of highly interesting work in bio-chemistry, like electrophoresis of proteins, should contribute to our understanding of iontophoretic problems. Experience with amblyopic eyes where visual function improves after many years of disuse, leads to the idea that dining the electric stimulation of the retina an electro-phoretic process is going on in the retina itself which causes the visual purple, a protein, to migrate into the rods and cones to a greater extent than before stimulation and causing corresponding changes in the size of rods and cones. There may be real ion transfer between the elements of the retina. Furthermore, the mere application of the electric galvanic current to the eye causes a release of acetyl choline in some tissues of the eye, presumably in the retina too. If we use the galvanic current to carry vasodilator drugs into the eye so that they are anchored for a long time to the eve tissues they are probably absorbed by vessels and brought into the inner eye or they come after absorption in the systemic circulation back into the already sensitized retina. Eserine is used as a vasodilator and with the intention of prolonging the action of acetyl-choline by destroying some of the choline esterase. All factors combined, electric current plus vasodilators contribute to a better circulation in the tissues of the eye particularly in the retina and the optic nerve. Thus the oxygen supply for these sensitive structures is increased in normal as well as in pathologically affected tissues. The increased oxygen supply means improver.7 visual function in a temporary way when iontophoresis is applied as a diagnostic measure. When iontophoresis is applied for a longer time, it is a therapeutic measure with visual improvement of a more lasting nature.
| Summary|| |
The theory and advantages of introducing drugs into the eye by iontophoresis are described. Methods of iontophoresis are described and the strengths of the various solutions used for the purpose are listed.
Experiences in affections of the different parts of the eye, inflammatory, vascular and degenerative, are stated.
An attempt has been made to familiarise Ophthalmologists with the practical application of iontophoresis, and to impress the growing importance of this form of therapy, which can also be used for diagnostic and prognostic purposes in cases of an opaque vitreous due to haemorrhage or opacities
| References|| |
Adler, F. H., (1953), Physiology of the Eye, P. 338, C. V. Mosby Co. St. Louis.
Boyd, J. L., (1942), A. M. A. Arcli. of Ophth. 28, 205.
Erlanger, G. (1954),
Fleming, N., (1943), Brit. J. Ophth.27 ;
Klein, M., (1940), Ch. 47 in Modern Trends in Ophthalmology by F. Ridley and A. Sorsby, Butterworth & Co., London, p. 508-514.
C., (1949), Amer. J. Ophth. 32, 135.
Salmann, von. L.(1945)Arch of ,Ophth. 34, 195.
Swan, K. C. (1953), Arch. of Ophtti.,49,419.
Selinger, E.,(1947) ,
A. M. A., Arch. of 'Ophth. 38, 645.
Smith, V. L., (1951), Amer. J. Ophth. 34. 698.
Witzel, S. H., Fielding, I. Z., and Ormsby, H. L., (1956), Amer. J. Ophth. 42, 89
[Figure - 1], [Figure - 2]
[Table - 1]