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ARTICLE
Year : 1958  |  Volume : 6  |  Issue : 3  |  Page : 41-48

Iontotherapy in ophthalmology


K. B. Haji Bachooali Free Ophthalmic Hospital, Parel, Bombay, India

Date of Web Publication8-May-2008

Correspondence Address:
B D Telang
K. B. Haji Bachooali Free Ophthalmic Hospital, Parel, Bombay
India
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Source of Support: None, Conflict of Interest: None


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How to cite this article:
Telang B D. Iontotherapy in ophthalmology. Indian J Ophthalmol 1958;6:41-8

How to cite this URL:
Telang B D. Iontotherapy in ophthalmology. Indian J Ophthalmol [serial online] 1958 [cited 2019 Jun 26];6:41-8. Available from: http://www.ijo.in/text.asp?1958/6/3/41/40722

Table 1

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Table 1

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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 Top


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 Top


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 Top


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 Top


Drugs have been classified so as to indicate the polarity of active electrode. (See Table below).


  Iontophoresis in Ophthalmic Therapy Top


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.

Conjunctival Affections

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.

Corneal Affections

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.

Corneal Opacities

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.

Iridocyclitis

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.

Neuralgia

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 Top


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[11]

 
  References Top

1.
Adler, F. H., (1953), Physiology of the Eye, P. 338, C. V. Mosby Co. St. Louis.  Back to cited text no. 1
    
2.
Boyd, J. L., (1942), A. M. A. Arcli. of Ophth. 28, 205.  Back to cited text no. 2
    
3.
Erlanger, G. (1954), Ophthalmologica 128  Back to cited text no. 3
    
4.
Fleming, N., (1943), Brit. J. Ophth.27 ; 354.  Back to cited text no. 4
    
5.
Klein, M., (1940), Ch. 47 in Modern Trends in Ophthalmology by F. Ridley and A. Sorsby, Butterworth & Co., London, p. 508-514.  Back to cited text no. 5
    
6.
Locke, J. C., (1949), Amer. J. Ophth. 32, 135.  Back to cited text no. 6
    
7.
Salmann, von. L.(1945)Arch of ,Ophth. 34, 195.  Back to cited text no. 7
    
8.
Swan, K. C. (1953), Arch. of Ophtti.,49,419.  Back to cited text no. 8
    
9.
Selinger, E.,(1947) , A. M. A., Arch. of 'Ophth. 38, 645.  Back to cited text no. 9
    
10.
Smith, V. L., (1951), Amer. J. Ophth. 34. 698.  Back to cited text no. 10
    
11.
Witzel, S. H., Fielding, I. Z., and Ormsby, H. L., (1956), Amer. J. Ophth. 42, 89  Back to cited text no. 11
    


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