Explantation of a foldable silicone intraocular lens

PURPOSE: We used a novel technique for explanting an improperly oriented silicone intraocular lens. METHODS: The elastomeric property of silicone was used to deform the optic and remove the intraocular lens in one piece. RESULTS: We explanted a flexible intraocular lens without compromising the integrity of the original wound, posterior lens capsule, or corneal endothelium. CONCLUSIONS: The technique offers a superior means of intraocular lens explantation while retaining the benefits of small-incision cataract surgery.     

Effect of intraocular lens design on neodymium:YAG laser capsulotomy rates

The activity of alkaline phosphatase (AP) was studied in adults of highly active (HA) and low active (LA) Drosophila melanogaster strains and their F1 hybrids, both under normal conditions and after a heat shock (38 degrees C). Under normal conditions, the HA strain expressed a higher AP activity compared to that in the wild-type strain Canton-S and dominated in respect to this character. The AP activity showed a sexual dimorphism, as it was higher in females of both strains. Heat shock (38 degrees C) induced no alterations in the AP activity of D. melanogaster.     

Secondary intraocular lens implantation

Mere aphakia is not an indication for secondary intraocular lens implantation. However, many patients with positive indications may be benefited most strikingly by this procedure. These indications are illustrated and results of the author's first 65 secondary implantations are analyzed.     

Silicone versus polymethylmethacrylate intraocular lenses with regard to capsular opacification

Between May 1996 and May 1997, a total of 398 patients (321 males, 77 females) were registered at our institute for trans-telephonic electro-cardiographic monitoring (TTEM). Their age ranged from one month to 95 years. Almost two-third (67%) of patients were from Delhi and one-third (33%) from other places in India and neighbouring countries. Clinical profile of these patients was post-bypass surgery, post-myocardial infarction, chest pain for evaluation, post-percutaneous transluminal coronary angioplasty, chronic stable angina, evaluation of palpitations, arrhythmias, and pace-maker follow-up. Out of 664 symptomatic transmissions, 568 (86%) were received for cardiac symptoms and 96 (14%) for non-cardiac symptoms. Seventy-nine percent patients had chest pain or palpitations at the time of transmission, whereas 21 percent had other symptoms like chest discomfort, breathlessness or dizziness. The electro-cardiograms were transmitted within one hour of the onset of chest pain in 84 percent, palpitations in 78 percent and dizziness in 75 percent. Of patients with symptomatic transmissions, 628 (95%) required either reassurance or drug-dose adjustment and outpatient department review. Only 36 (5%) patients were hospitalised as an emergency, and out of these only 19 (3%) needed acute management. In conclusion, trans-telephonic electro-cardiographic monitoring is a very convenient and an 'all-time-available' monitoring facility for establishing patient-physician contact in the shortest time. It is useful in rendering instant advice for hospitalisation in emergency situations while avoiding unnecessary visits to the hospital.     

Placement of a secondary foldable intraocular lens over a capsule remnant

A bilaterally aphakic patient received a silicone intraocular lens (IOL) over an intact capsular bag. The fellow eye had a large capsule rupture. Implantation of a 3-piece silicone IOL was attempted over the capsule remnant and achieved without complication. One year postoperatively, the IOL remained stable.     

Endothelial physiology and intraocular lens implantation

The endothelium is the cellular monolayer which lines the posterior surface of the cornea. This layer is important in clinical ophthalmology because it is vital to maintenance of the transparency of the cornea and vision through its pump and barrier functions which limit the ingress of fluid into the cornea from the aqueous. When the function of the corneal endothelium becomes compromised, the corneal stroma swells as it hydrates. Subsequently, epithelial bullae form with painful recurring epithelial erosions, and finally corneal scarring and blindness result. The relatively vulnerable position of the corneal endothelium renders it susceptible to iatrogenic injury during intraocular procedures, especially IOL implantation: the poor regenerative (mitotic) capacity of the human corneal endothelium limits its ability to recover normal function once it is injured.     

Endothelial damage from intraocular lens insertion

Previous studies have shown that approximately 40 per cent of the corneal endothelial cells can be lost at the time of intraocular lens insertion. Momentary contact between the methacrylate surface and the endothelial cells causes an adhesion between these surfaces and results in extensive cell damage upon separation of the surfaces. This type of damage appears to be due to a biophysical interaction between these surfaces and may be avoidable by altering the surface of the lens.     

Secondary intraocular lens implantation in children

OBJECTIVE: The study was designed to determine the visual outcome and indication of secondary posterior chamber intraocular lens (IOL) implantation. METHODS: The operation was performed on 34 eyes with aphakia in children after separation of posterior iris synechia from posterior capsule and formation of a posterior chamber space large enough to insert an intraocular lens. Based on whether the integrity of the posterior capsule was complete or not, various techniques of secondary IOL implantation were adopted. RESULTS: The follow-up periods ranged from 6 to 24 months. The results showed that 29 of the eyes (85.29%) achieved a post-operative corrected visual acuity equal to or better than that of the best corrected visual acuity before the surgery; the postoperative uncorrected visual acuities in 16 eyes (47.06%) and corrected visual acuities in 28 eyes (82.35%) reached 0.5 or better. CONCLUSION: Secondary posterior chamber IOL implantation is a safe and effective method in children who have a complete or partial posterior capsule.     

Spontaneous extrusion of an intraocular lens implant

A 51-year-old man with ankylosing spondylitis had intracapsular cataract extraction and anterior chamber lens implantation in the left eye in 1985. He had localized sclerokeratitis around the corneal section and a protracted anterior uveitis in the immediate postoperative period. He developed a spontaneous extrusion of the implant in 1991 (six years later). The extrusion was through a site 1.5 mm posterior to the previous surgical section. There was no corneal decompensation or corneal melt and no history of trauma. Signs of localized scleritis were present. It is suggested that anterior chamber lens implantation should be avoided under these circumstances.     

Theoretical and practical performance of a concentric bifocal intraocular implant lens

Some results from a survey of 43 patients who had a monofocal intra-ocular-lens (IOL) in one eye and a concentric bifocal intra-ocular-lens in the fellow eye are reported. Twenty patients with 6/9 or better post-operative visual acuity in both eyes, participated in the main part of the study. Optical transfer functions for the bifocal lens showed that, compared to an optimal single-vision correction, there is a 50% contrast degradation of the distance retinal image across all spatial frequencies above around 3 c/deg. For the patients in the main study, there was a close correspondence between practical measurement of contrast sensitivity and the theoretical predictions of the modulation transfer functions. Measuring contrast sensitivity proved an effective means of assessing misalignment of the bifocal IOLs.     

Capsular bag distension after optic capture of a sulcus-fixated intraocular lens

The aim of the present study was to determine the effect of chronic intracerebroventricular infusion of angiotensin II (ANG II) on the expression of brain AT1 receptors in young (3-4 weeks) rats. One week of icv ANG II infusion produced a significant increase in brain AT1 receptor protein (Western blot) and mRNA (relative RT-PCR) expression. These data raise the possibility that ANG II may play a role in postnatal expression of brain AT1 receptors.     

Reduced intraocular pressure after phacoemulsification and posterior chamber intraocular lens implantation

PURPOSE: To ascertain whether phacoemulsification with posterior chamber intraocular lens (IOL) implantation causes long-term reduction in intraocular pressure (IOP). SETTING: Private practice, Kempten, Germany. METHODS: Intraocular pressure was measured in both eyes of 120 consecutive patients who were unilaterally phakic after phacoemulsification a mean of 17 months +/- 17 (SD) previously. Mean age of the 36 men and 84 women was 76 +/- 10 years. Data were analyzed using binomial distribution and the Wilcoxon signed-rank test. RESULTS: The median ratio of IOP in the pseudophakic eye to IOP in the phakic eye was 0.83. The IOP was lower in the pseudophakic eye in 96 patients (80%). The median IOP was 12 mm Hg in the pseudophakic eyes and 14 mm Hg in the phakic eyes (P < .001). As measured by the interquartile range, IOP distribution was more centered in the pseudophakic than in the phakic eyes (3 versus 4). The IOP in the pseudophakic eyes remained lower to the last measurement, 5 years postoperatively, and appeared to be independent of patient age. Lower IOP in the pseudophakic eye was consistently present in patients with higher IOP in the phakic eye (16 to 22 mm Hg). CONCLUSION: Phacoemulsification with posterior chamber IOL implantation reduced IOP in most but not all patients with a preoperative IOP of 22 mm Hg or less. This reduction was maintained over several years, with the cause yet to be established. Lower IOP may decrease the risk of subsequent glaucomatous nerve damage in these patients.     

A prospective evaluation of a diffractive versus a refractive designed multifocal intraocular lens

OBJECTIVE: To evaluate prospectively a diffractive (811E, Pharmacia; power add +4.0 D) versus a refractive (PA154N, Allergan; power add +3.5 D) designed multifocal lens. PARTICIPANTS: Eighty patients planned for cataract surgery without additional ocular pathologies were randomized into the diffractive or refractive group, respectively. INTERVENTION: A standardized no-stitch phacoemulsification with implantation of one of the two multifocal lenses was performed in each patient. MAIN OUTCOME MEASURES: Distance and near-visual acuity, contrast sensitivity, low contrast visual acuity, glare visual acuity, and depth of focus were measured after surgery. RESULTS: All treated patients had best-corrected visual acuities of 20/30 or better. Near-uncorrected vision was significantly better (P < 0.0001) with the diffractive lens (mean, J1) than with the refractive lens (mean, J4). Low contrast visual acuity (61 +/- 12% versus 59 +/- 9%), glare visual acuity (39 +/- 19% versus 38 +/- 14%), and contrast sensitivity (1.48 +/- 0.08 versus 1.50 +/- 0.12) were not significantly different between the groups. CONCLUSIONS: Both lens designs showed satisfactory functional results with advantages for the diffractive lens design.     

Posterior chamber intraocular lens use in children

PURPOSE: The authors report on the efficacy of intraocular lens implantation during pediatric cataract surgery and the results of a consecutive series of intraocular lens implantation in children. METHODS: Twenty-one children underwent implantation of intraocular lenses in 23 eyes. Twenty-one surgeries were primary implantation immediately following anterior lensectomy. Two surgeries were secondary implantations. Primary posterior capsulectomy was performed in 18 of 21 primary implantations. All but two eyes underwent a primary anterior vitrectomy. Topical prednisolone acetate was administered in all cases. Oral prednisone was administered in 17 of 23 cases. Pre- and postoperative visual acuity, cycloplegic refraction, and postoperative complications related to inflammation such as intraocular lens (IOL) capture, IOL decentration, and posterior capsule opacification were examined. RESULTS: Eighteen of 23 eyes have achieved a visual acuity of 20/40 or better. None of the cases in which oral prednisone was used developed complications related to postoperative inflammation. One of the six cases (17%) in which oral prednisone was not used developed such complications. CONCLUSION: Intracular lens implantation accompanied by primary posterior capsulectomy, anterior vitrectomy, and management of postoperative inflammation appears to provide appropriate and safe optical rehabilitation in children.