|Year : 1982 | Volume
| Issue : 5 | Page : 457-459
Iris claw type intraocular lenses
Dept of ophthalmology Medical College, Amritsar, India
Dept of ophthalmology Medical College, Amritsar
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Singh D. Iris claw type intraocular lenses. Indian J Ophthalmol 1982;30:457-9
| The working of the claw|| |
The ring like haptic portion of the implant has a cut in it that gives it the property of a claw. This claw can hold the iris tissue by pinching [Figure - 1]. The principle was first used by Jan Worst.
The present study records the iesults of 138 intraocular lens implantations with a follow up of 2 months to 18 months. The following lens designs have been used [Figure - 2].
Type I : It has "Copeland type" projections at 6 and 12 0' clock and is designed to be temporarily fixed and centred by the pupil, prior to claw fixation, after which the lens is freed from the pupil (59 cases).
Type II: It has no projections and has to be almost free floated in front of the iris, before the iris is led into the claw for fixation (65 cases).
Type III: It has only one claw. The finger like projection goes under the pupillary margin opposite to the claw (14 cases).
| Procedures for cataract extraction intracapsular extraction|| |
All intracapsular extractions were done by Amritsar method, with or without a-chymotrypsin.
| Extracapsular extraction|| |
Planned extracapsular extraction is done with a 10-2 opening into the anterior chamber. The fluid used for irrigation is lactated ringer solution. The posterior capsule is polished with a Kritz scratcher.
| How the iris tissue is pinched into the claws|| |
All the three types of implants illustrated show unequal size of claws. The fixation of the implant is done after its optical part has been centred on the pupil. The implant is steadied by a delicate utility forceps that holds the smaller claw of the implant. While the ens is kept steady, another delicate forceps lifts a small pinch of the claw thus carrying iris tissue with it. As the iris tissue passes through the claw, it gets pinched. The forceps are withdrawn.
| Closure of the incision|| |
The incision is closed with 8 to 12 stainless steel sutures. Before the last suture is applied, the air in the anterior chamber is replaced by fluid. Dexamethasone 2 mgm is injected under the conjunctiva. Post operatively oral steroids used in tapering doses for about a week.
| Observations|| |
Total of 138 cases were operated whose age vat ied from below 10 years to over 60 years. There were 89 males and 49 females. Types of cataract were : Presenile or senile 120; Traumatic : 12 and Zonular 1. Intracapsular lens extraction was done in 31 and extracapsular in 102. In 5 cases secondary lens implantation was carried out.
Vitreous prolapse occurred in one case of intracapsular extraction and 5 cases of extracapsular extraction, three of them being cases of traumatic cataract. Vitrectomy or aspiration of central vitreous was done as required.
| Postoperative complications|| |
Striate keratitis; l t (7.9%); small hyphaema : 3 (2.1%); Uveitis . Severe 3 (2.1%) and mild 5 (3.6%); Choroidal detachment 1 (0.7%) Aphakic glaucoma 1 (0.7%0); tilted lens due to vitreous tag 1 (0.7%)
Visual results : 6/5 : 9 cases 6/6 : 34 cases 6/9 : 38 cases 6/12 : 29 cases 6/18 : 15 cases 6/24 : 4 cases 6/36:4 cases 6/60: 3 cases Less than 6/60 : 2 cases.
The final average visual acuity in this series was 0.66. The average visual acuity in traumatic cases was 0.59. Out of the patients who had vision less than 6/12, there were explainable ocular disorder unrelated to the implanted lens.
| Discussion|| |
The intraocular lenses employing claw principle for fixation are suitable for primacy implantation after intracapsular or extracapsular surgery. They are suitable for secondary implantation after both intra-and extracapsular surgery. They are also suitable for traumatic cataracts. These lenses have therefore, the widest field of indication than any other design of lens. This quality makes them attractive for the countries, where intraocular lens implantation has yet to take roots.
The surgical technique for insertion of iris claw lenses in the various clinical situations is very demanding and exacting. There is a need to familiarize oneself with every small detail of the surgical technique. According to Jan Worst, "This is a lens for all purposes, but not for all surgeons".
| Acknowledgement|| |
I am indebted to Jan Worst, Edwin Olmos (Bolivia) and Hampton Roy (USA) for their help and guidance.
| References|| |
Worst, J.G.F., 1980 Personal communications. 2. Singh, D., Nirankari, M.S. and Singh, M., 1977, Proceedings of All India Ophthalmological Society, Vol. 33, pp. 23-29.
[Figure - 1], [Figure - 2]