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   Table of Contents      
ARTICLES
Year : 1975  |  Volume : 23  |  Issue : 1  |  Page : 27-31

Therapeutic applications of hydrophilic soft contact lenses


Municipal Eye Hospital, Grant Road, Bombay, India

Correspondence Address:
K R Mehta
Sea Side, 147, Colaba Road, Bombay-5
India
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Source of Support: None, Conflict of Interest: None


PMID: 1158420

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How to cite this article:
Mehta K R, Sathe S N, Karyekar S D, Dave S. Therapeutic applications of hydrophilic soft contact lenses. Indian J Ophthalmol 1975;23:27-31

How to cite this URL:
Mehta K R, Sathe S N, Karyekar S D, Dave S. Therapeutic applications of hydrophilic soft contact lenses. Indian J Ophthalmol [serial online] 1975 [cited 2020 Aug 4];23:27-31. Available from: http://www.ijo.in/text.asp?1975/23/1/27/31334

Hydrophilic soft lenses were discovered by Wichterle and Lim at Czechoslovakia in 1960 and are based on a plastic material, Poly HEMA (Poly 2-hydroxyethylmethacrylate). The property of hydration in a soft lens is the most important factor in therapeusis. High hydration lenses, hydrating 6G%,-7G;o in saline, are best suited for therapeutic use as they are more soft and pliable, with a better "bandage" effect and - better transmission factors for oxygen, electrolytes and drugs. Low hydration lenses (20-30%) are firmer, give better vision and hence are preferred for cosmetic and optical applications.

Sterilization : Despite never techniques, the most reliable and cheap method is to boil the lens in a water bath for 20 minutes or in a pasteurizer. [3] The other alternatives are : a) Usage of hydrogen peroxide and bicarbonate of soda, effective, but with the disadvantage that occasionally all peroxide is not removed to the detriment of the cornea. b) Cleaning solutions: Flexol 4 (Burton Parsons) and Hexaphene. (Barnas Hind). These are the most convenient but the solutions are costly. The life of the lens is immeasurably increased by minimal handling.

Selection and fitting technique : Ideally selection is based on matching the corneal curvature readings (by a keratometer) to the inside curve of the soft contact lens. The alter­native of `Trial and Error' for fitting works equally well [10] The criteria of the 'best-fit' lens is taken as good stability of the lens with vertical movements on a full blink of less than 2min, with no movement on lateral gaze, and no air bubble under the lens after 15 minutes. (In explanation, a flat or loose fit has no lens stability, while a steep tight fit has an air bubble.)

Supplementary eye drops : The danger of absorption by the lenses of various preserva­tives in standard eye drops has been exag­gerated. As a rule, fresh solution without pre­servative is preferred, for short time use routine drops can be used over the soft lens safely.

Therapeutic application : Soft lenses have been used with good results by us in 1) corneal ulcers. 2) recurrent epithelial erosions. 3) simple keratitis sicca and Stevens Johnson syndrome. 4) neurotropic keratitis 5) bullous keratopathy 6) splint following keratoplasty and superficial corneal keratectomies. 7) alkali and thermal burns of the cornea. 8) penetrating corneal injuries 9) corneal fistulae and 10) as ocuserts with supplementary drugs.


  I. Corneal Ulcers Top


Indolent non-healing corneal ulcers, with negative smear and culture, are common prob­lems in hospital out-patients. The cases were selected for the clinical trial after conventional techniques including scraping and cauterization were ineffective. As concomitant iritis was invariably present in all cases, the pupils were dilated prior to insertion of the lenses. A trial fit on the normal eye is a useful adjunct for a good fit. In our series of 15 cases, we had significant success mall cases. Ulcers of about 3mm diameter healed in a week while larger ulcers took longer, upto 15 days for a 7mm ulcer. Therapeutic success was based on complete healing of the ulcer with restoration of epithelial continuity and comfort. The lenses were tolerated very well and no complication was encountered. A daily follow up is essential. The use of fluorescein is not possible as soft lenses permanently absorb the dye. Under the biomicroscope the evaluation of re-epitheliali­sation is possible in most cases with the lens in place.

Apparently the lens acts as a very efficient protective bandage shielding the ulcer from the repetitive irritative influence of the eyelids during blinking and from other noxious stimuli [6],[13] . In addition the lens provides a structural framework upon which the regenerating epithelium may grow [18] as the epithelium bridges the ulcer and covers its surface rather than grow into its depths. On removing the lens regenerating membrane remains intact and initially looks like a flaccid bullae. In time it sinks down into the ulcer crater and adheres to its surface. This membrane is extremely delicate and easily comes off. To prevent recurrences the lens is not removed for three days after the ulcer has healed fully.


  II. Recurrent Epithelial Erosions Top


We have fitted soft lenses on a small series of six cases. If the epithelium has to have a chance to reattach firmly, the lens has to be worn over a protracted period of time. Early discontinuation of lens wear precipitates a recurrence. With minimal thickness soft lenses worn day and night for 10 weeks continuously, results are good. A bland ointment is inserted every night after discontinuing lenses.


  III. Drying Syndromes Top


(a) Simple keratitis sicca: These in reality are ideal cases for soft lens therapy [7] . High hydration lenses with supplementary instillation of half strength (0.45%) normal saline at four hourly intervals suffice adequately. Some patients produce a stringy mucous which adheres to the lenses and necessitates frequent cleaning. This problem can be kept at bay by using methylcellulose 0.5% drops thrice a day. Since the lid movements of these eyes are normal the lenses can be removed at night prior to sleep and reinserted in the morning. The lenses must be worn for a protracted period of time and hence individually powered soft lenses can be useful. This simple procedure deserved a trial before resorting to lengthy surgical procedures like parotid duct trans­plants.

(b) Steven Johnson syndrome : In no con­dition is the result of soft lens therapy so dramatic than in these cases. Stevens Johnson syndrome has its most serious chronic ocular sequelae [6] . The skin lesion usually disappears, and secondary bacterial infection is rare with antibiotics. The only residual defect, after an acute phase of erythema multiforme exudivatum is conjunctival scarring, immobilization of the globe with opacification of the cornea and blindness. The two cases of Stevens Johnson Syndrome that u e have handled were both secondary to sulphonomides. In the first case, a 22 year male from Belgaum, referred to us early with xerosis and a small corneal ulcer, responded to soft lens therapy rapidly. The lenses v ere worn daily for four months and are discontinued now though, since his eye is still a little dry, he instills - ,ethylcellulose drops daily. The second case, a 16 Near male, reached us late. His right eye was lost due to a necrotising corneal ulcer. The left eye had developed extensive symblepharon which was surgically released, and the patient was put on soft lenses. Though only a modicum of vision was maintained, the patient was comfortable and wears the lenses daily. We realize that two cases are a small number to comment upon but we feel that soft lenses could save a large number of eyes lost by delay and indecision. Rarely is there a more innocuous treatment so effective and with such far reaching consequ­ences [7].


  IV. Neurotrophic Keratitis Top


The efficacy of soft lenses in this condition is well established. Most often it tends to occur following alcohol injections or surgery for trigeminal neuralgia or following herpes zoster ophthalmicus. The classical treatment of tarsorrhaphy, with its disfiguring cosmetic appearance was followed by flush fitting plastic shell' 6 which tended to abrade the cornea readily and required expert maintainence. Soft lenses protect the cornea with excellent cos­metic appearance with good visual acuity. The results are excellent. Our longest follow up is of 8 months.


  V. Bullous Keratopathy Top


We have managed a small series of 7 cases with aetiology varying from glaucoma 3 cases; long standing uveitis 2 cases; aphakic bullous keratopathy 2 cases and Fuchs dystrophy 1 case. The soft lens in bullous keratopathy must be fitted as flat as possible with maximum stability. The pain, photophobia, tearing and blepharospasm tend to be relieved rapidly and make the patient ambulant again. These constitute the most important advantage and in addition, the improved vision and possi­bility of hypertonic osmotherapy (instillation of 5% saline at three hourly intervals) are a great help. Visual acuity improves by render­ing the anterior corneal surface optically smooth and eliminating much of the anterior astigmatism. Further improvement is due to the concomitant osmotherapy reducing the stromal swelling caused by the descemets folds (Leibowitz [11] ). Though the bullae are flatter and lesser in number, observed by a biomicroscope with the lens in situ, after two days, it requires two to three weeks of wear before the bullae disappear. Bullae are due to some secondary pathology which must be taken into account" (EKP). Unlike EKP soft lenses do not provide an impermeable anterior membrane which pro­motes stromal swelling as fluid leaks through the endothelium. On the contrary soft lenses enormously augment the osmotically active agents. The difficulty in procuring the cyanoacrylate glue, and its potential toxic in acceptance, make it a poor second to hydro­philic soft lenses.


  VI. Splinting following Keratoplasty Top


Soft lenses are ideal for splinting and retaining lamellar grafts with three virgin silk stay sutures. The lens is kept in situ for 15 days. Typically the quantum of mucous formed around the sutures is absent and the eye is quiet, and tends to clear up rapidly. The patient is comfortable right from the beginning and bandaging can be stopped after four days as the lens is an effective barrier. The post graft visual results of penetrating keratoplasty are much better if soft lenses are used. Exces­sive astigmatism can be controlled by additional spectacles. A lens inserted after superficial corneal keratectomies gives immediate relief, and rapid healing, again bandaging is not essential.


  VII. Alkali and Thermal burns of Cornea Top


In the treatment of alkali burns of the cornea, soft lenses reduce the chemosis and relieve the need for continuous patching. Re­peated epithelial erosions leading to stromal ulcers are common with a generally reduced tear secretion. The soft lens, by protecting the cornea and augmenting the bathing tear fluid, assists in permitting the cornea to heal. The lens must be worn for at least six weeks after full healing has ensued as the chances of re­currence are there. Though the integrity of the eye is saved the invariable dense corneal scar­ring precludes a good visual result. We have handled two cases so far, in one we did a penetrating keratoplasty under cortisone cover with the return of useful vision. In the other, dense scarring after healing with vascularization led to an opaque graft. The results of other authors have also been, at best, equivocal [1] .


  VIII. Penetrating Corneal Injuries Top


It has been recommended that the corneal wounds should be linear, clean cut, of small size and good edges before they would respond to soft lenses and heal [12] . We have fitted the lenses on a variety of injuries, blunt and sharp, of a fairly large size, and of irregu­lar edges with excellent results as long as good apposition is present before inserting the lenses. The lens, as usual 'best-fit' is inserted after hydrating in distilled water, instead of saline, as it has, for a short time, extremely good adhesion [5] . Chloramphenicol drops instilled four hourly with the lens in situ, with appropriate systemic antibiotics. Lenses are removed after the wound has healed on slit lamp examination. The advantages of usage of soft lenses in penetrating injuries are:- a) Good healing and excellent coaptation with minimal astigmatism and a thin hairline scar. (b) No instrumentation required. Not all centres are provided with excellent corneal sutures or microneedles. (c) Immediate sealing of the wound with no delay. Chamber reforms rapi­dly. Chances of secondary infection are less. (d) Needs no level of technical competence to insert the lens. e) As the eye can be kept open soon after the lens insertion, the wound and the eye can be followed up more frequently with­out risk of reinfection.


  IX. Corneal Fistulae Top


We have handled a wide range of fistulae from penetrating corneal ulcers to leaking wounds following suturing. The technique is identical in all. Siedola fluorescein test is first done to ascertain the leaking site, and the lens is inserted after flushing off the excess of fluorescein. As most fistulae heal in 3-5 days, the lens is removed after a week. The lens may be reapplied if the leakage has not stopped, but it is a rare occurrence.


  X. Gradual release with Supplementary Drugs Top


Soft lenses by their property of hydrating in, and subsequent releasing the supplementary drug in graduated quantities, acts as an ocusert, which by definition are tampons for conjunc­tival sac. Various drugs can thus be released eg. drosyn, pilocarpine, cortisone, IDU etc". Our trials with Drosyn 5% indicate a far superior prolonged response in the treated soft lens eye as to the eye with only the drop and no lens. A similar response was obtained with pilocarpine, with she additional benefit that patients not responding to Pilocarpine 4°o drops, respond to a soft lens Pilocarpine combination. It would be false however to assume that soft lens therapy is the answer to the vexing problem offered by glau­coma but it is a useful adjunct, and is safer and simpler to use a soft lens with a simple medication rather than utilizing the longer acting drugs with more side effects.


  Summary Top


The clinical success reported here supports the observations and enthusiasm of others. We are well aware that with all new therapeutic approaches, the initial clinical experience is tem­pered with caution as cases proceed. Perhaps this work will help to spark the necessary enthus­iasm for a long overdue investigation into the therapeutic opportunities offered by the hydro­philic soft lens.

 
  References Top

1.
Brown S. J.; Tragakis M.A., Pearse D. B. 1972., p. 224 C. V. Mosby.  Back to cited text no. 1
    
2.
Buxton Jorge, Lockc Clyde, 1971, Amer. J. Oph­thal. 72, 532 1972.  Back to cited text no. 2
    
3.
Dallos J. & Hughes W. H., Sterilisation of Soft Lenses 1972. Brit. J. Ophthal. 50/2, 114.  Back to cited text no. 3
    
4.
Duggan J. W. & Gaines S. R. 1951 Amer. J. Ophthal. 34, 189.  Back to cited text no. 4
    
5.
Farnik S. 19.,6. Optician 152, 299.  Back to cited text no. 5
    
6.
Gasset A. R. & Kaufman H. E. Therapeutic uses of hydrophilic lenses, 1970. Amer. J. Oph­thal. 69, 252.  Back to cited text no. 6
    
7.
Gasset A. R. & Kaufman H. E. 1971. Amer. J. Ophthal. 71, 1185.  Back to cited text no. 7
    
8.
Gasset & R. & Kaufman H. E. 1971. Amer. J. Ophthal. 72, 376.  Back to cited text no. 8
    
9.
Gould H. L. 1973. Transaction of the New Orleans Academy of Ophthalmology. C. V. Mosby.  Back to cited text no. 9
    
10.
Kaufman H. E. & Gasset A. R., 1969. High­lights Ophthal. 12 (3), 177,  Back to cited text no. 10
    
11.
Kaufman H. E. & Gasset A. R. 1969. Amer. J. Ophthal. 67, 38.  Back to cited text no. 11
    
12.
Leibowitz H. M. Penetrating Corneal wounds 1972. Arch. Ophthal. 88, 602.  Back to cited text no. 12
    
13.
Leibowitz H. M. & Rosenthal P., 1971. Ophthal. 85, 160.  Back to cited text no. 13
    
14.
Leibowitz H: M. & Rosenthal P., (1971) Arch. Ophthal. 85, 283.  Back to cited text no. 14
    
15.
Podos S. M. Becker B. Ascheff C. Hartestein J. 1972. Amer. J. Ophthal. 73, 336.  Back to cited text no. 15
    
16.
Ridley F. 1973. Arch. Opthal. 70, 740.  Back to cited text no. 16
    
17.
Takahashi G. M. Leibowitz H. M. 1971. Kera­topathy. Arch. Ophthal. 86, 133.  Back to cited text no. 17
    
18.
Westerhout David, Therapeutic uses of the soft lens and combination lens. The Contact Lens Vol. 4 Nos 5, 1. (1973).  Back to cited text no. 18
    




 

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  In this article
Summary
I. Corneal Ulcers
II. Recurrent Ep...
III. Drying Synd...
IV. Neurotrophic...
V. Bullous Kerat...
VI. Splinting fo...
VII. Alkali and ...
VIII. Penetratin...
IX. Corneal Fistulae
X. Gradual relea...
References

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