Year : 1984 | Volume
: 32 | Issue : 6 | Page : 516--518
Extended wear contact lenses using high water contact lenses in aphakia
M Srinivasan, Gullapalli N Rao, James V Aquavella
The Department of Ophthalmology, University of Rochester Medical Centre, Rochester, New York, USA
Gullapalli N Rao
M.D. 919 Westfall Road Rochester, New York
|How to cite this article:|
Srinivasan M, Rao GN, Aquavella JV. Extended wear contact lenses using high water contact lenses in aphakia.Indian J Ophthalmol 1984;32:516-518
|How to cite this URL:|
Srinivasan M, Rao GN, Aquavella JV. Extended wear contact lenses using high water contact lenses in aphakia. Indian J Ophthalmol [serial online] 1984 [cited 2020 Sep 28 ];32:516-518
Available from: http://www.ijo.in/text.asp?1984/32/6/516/30857
Extended wear of contact lenses is one of the most commonly used modalities for the correction of aphakia at the present timer ,. Extended wear is a concept based on the premise that the normal metabolic requirements of the cornea are met with the presence of u contact lens in the eye. One of the basic prerequisites for the normal metabolism of the cornea is adequate oxygen transmission. Hydrophilic lenses have been developed which allow adequate oxygen transmission because of their higher water content. In this study, we have made a retrospective analysis of 420 patients who were fitted with two types of high water content hydrophilic lenses for the correction of aphakia and analyzed the results.
PATIENTS AND METHODS
A total of 420 patients who were fitted with high water content hydrophilic contact lenses on an extended wear basis were included in this study. 342 of these patients had intracapsular cataract extraction while the remainder (78) had extracapsular cataract extraction using standard microsurgical procedures. The follow-up period ranged from six months to four years. The age of these patients ranged from 52 to 85 with a mean of 69.4 years. All these patients were operated by two surgeons (JVA and GNR). The contact lenses were fitted according to the criteria established for the fitting of hydrophilic lenses.
Two kinds of contact lenses were employed, namely Permalens and Sauflon. Permalens is made up of Perfilcon A with a water content of around 70 per cent. Sauflon is Lidofilcon A with about 70 to 75 per cent, water content. 328 of these were fitted with Permalens while 92 were fitted with Sauflon.
The follow-up of these patients included evaluation at one hour, one day, one week, one month and three months following the lens insertion and every six months later on. None of these patients were treated with any routine medications other than for the routine post-operative care in the immediate postoperative period. A few of these are on artificial tear substitutes because of marginal keratoconjunctivitis sicca in these patients.
The overall visual results in these patients have been very encouraging [Table 1] with 301 (72%) of these patients achieving a final visual acuity of better than 20/40 (6/12). Of the remaining, 70 patients (17%) bad a visual acuity of better than 6/24. The visual acuities in all these eyes could be improved to the range of 6/9 to 6/6 with spectacle overcorrection. The main reason for poor visual acuity seems to be poor fitting characteristics and changing hydration with change in environment. Refitting with a different lens often eliminated the problem.
A number of complications were encountered in this group of patients and these are listed in [Table 2]. As is obvious from the table lens deposits constitute one of the most frustrating problems requiring frequent lens replacement. The average replacement rate was 1.8 lenses per patient per year in this series. No significant difference was found between the two lenses in terms of lens deposits.
Tight lens syndrome occurred in 41 of the patients at different times. This was much more common in patients fitted with Permalens (38 out of 328 eyes) compared to those with Sauflon lens (3 out of 92 eyes).
Corneal ulcers from where bacteria could be isolated occurred in 8 of the 420 eyes and all these eyes responded to prompt treatment with appropriate antibiotics. One of these eyes needed corneal transplantation for the resultant central scar. Non-infectious infiltrates occurred in 22 of the eyes which responded to cessation of lens usage and topical steroids and lubricants.
Vascularization was seen in 128 of the eyes. Deep stromal vascularization, however, occurred in only 8 of the eyes which resolved on discontinuing the lens. In one of these eyes where the patient did not comply with the follow up routine, lipid infiltration in the stroma led to corneal scarring.
Allergic conjunctivitis occurred in 49 of the eyes with 18 of these developing signs of giant papillary conjunctivitis. The rest of the eyes demonstrated manifestations of conjunctival chemosis.
Extended wear of contact lenses is a viable option for the correction of aphakia at the present time. The successful outcome of this modality is dependent on basic principles of proper patient selection, proper patient instruction and proper followup .
It is obvious from this series that the success rate in terms of visual improvement is quite high. Our results are quite comparable to results of other investigators ,. The basic problems of failure relate to poor fitting characteristics of these lenses alongwith possible fluctuations in the hydration of lenses .
A number of complications have been reported with the usage of hydrophilic lenses . Although the incidence of these complications has become less in recent years, the potential still exists. Early recognition and prompt treatment are paramount importance in the avoidance of a number of sight threatening sequelae that might otherwise occur.
|1||Binder P.S., 1979, JCE Ophthalmol 15 : 32,|
|2||Gasset AR, Lobo L, Houde W., 1977, Amer J Ophthalmol 113: 85.|
|3||Rao GN., Norton SY, 1980, Contact Lens & Intraocular Lens J. 6 : 258,|
|4||Binder PS, Worthen DM, 1977, Amer J Ophthalmol 83 : 549,|
|5||Rao GN : Contact Lenses, Ed.: Dabezies, 0., (in press).|