Techniques of intraocular lens suspension in the absence of capsular/zonular support.

Implantation of intraocular lenses has become the standard of care in the aphakic state. Ideally, the lens is placed in the capsular bag, which affords stable fixation at a position closest to the nodal point of the eye. However, there will always be instances where this will not be possible. Congenital weakness of the lens zonules in various conditions, trauma, and surgical complications of cataract surgery are just some examples. In this article, we review the methods that have been devised to allow intraocular lens implantation in the absence of capsular or zonular support. These include anterior chamber angle and iris-fixated lenses, as well as posterior chamber iris- and scleral-sutured lenses. The various lenses are described, and the techniques involved, advantages and disadvantages, complications, and results of each method are discussed. It is hoped that this article will provide a comprehensive overview of ways to deal with a problem that can still result in a very good visual outcome for the patient. This is particularly relevant given the many recent developments and refinements of methods in implanting intraocular lenses.

An evaluation of the administration of sub-Tenon local anaesthesia by a nurse practitioner.

AIM: To evaluate the administration of sub-Tenon local anaesthesia (LA) by a nurse practitioner. METHODS: 106 consecutive patients listed for cataract surgery were given sub-Tenon's anaesthesia by a nurse practitioner. The surgical procedure was performed within 15 minutes of the administration of the LA. Pain, state and adequacy of anaesthesia, appearance of the eye, and patient anxiety were measured. Patients' experiences of this new nursing role were gained through interview. RESULTS: At the beginning of surgery, few patients showed eye movement in any of the four quadrants and the surgeons reported that akinesia was inadequate in only seven (7.1%) cases. Three patients (3.3%) gave a pain score of 3 out of 10 or above during surgery whereas the surgeons assessed the pain relief to be inadequate in eight (8.1%) cases. Five (5.3%) patients required a top up of anaesthesia and 51 (39.8%) patients developed conjunctival chemosis in two or more quadrants. Overall, patients' comments indicate that they were pleased with the new service. CONCLUSION: The results suggest that nurse practitioner delivered sub-Tenon LA is an effective and safe method of LA administration for cataract surgery.

Decompensation of a congenital retinal macrovessel with arteriovenous communications induced by repetitive rollercoaster rides.

PURPOSE: To describe a congenital retinal venous macrovessel that communicates with a cilioretinal artery and a retinal artery, and to report how this vascular anomaly decompensated as a result of repetitive rollercoaster rides. METHODS: Case report with serial fundus photography and fluorescein angiography. RESULTS: After a short period of intensive rollercoaster rides, a 19-year-old woman complained of reduced vision in one eye. Funduscopy and fluorescein angiography revealed a venous congenital retinal macrovessel with arteriovenous communications, and retinal exudation was visible at the termination of the anomalous vessel. Exudation resolved, and acuity recovered after a period of avoidance of rollercoaster rides. CONCLUSION: This case represents the first report of a retinal artery and a cilioretinal artery communicating with a congenital retinal macrovessel, and it suggests that such patients are at increased risk of retinal vascular decompensation if involved in activities associated with changes in g-forces, such as bungee jumping or rollercoaster rides.

Autogenous labial mucous membrane and banked scleral patch grafting for exposed retinal explants.

Following retinal detachment surgery, exposure of the scleral explant is uncommon and usually requires its removal. In patients with a history of multiple retinal detachment procedures or continuing vitreoretinal traction removal of an explant can lead to retinal redetachment. In such patients it is preferable to cover and retain an exposed explant rather than remove it. Various techniques have been described to cover exposed explants. If the exposed area is small a conjunctivoplasty or conjunctival graft is usually adequate. The use of banked scleral patch grafts has been described in the management of exposed orbital implants. We describe the use of this technique in combination with a labial mucous membrane graft in four patients with an exposed silicone retinal explant. With a minimum follow-up period of 11 months the explant remains covered in all patients.

Retinal detachment following excimer laser.

AIM: To report the clinical presentation, surgical management, and outcome of retinal detachment following excimer laser. METHODS: Retrospective analysis of retinal detachments observed in 11 eyes of 10 myopic patients who had previously undergone photorefractive keratectomy (PRK) or phototherapeutic keratectomy (PTK) by excimer laser. RESULTS: Symptoms of visual loss in two eyes were initially attributed to corneal haze. In 10 of 11 eyes visualisation of the retinal detachment and causative break was possible despite mild corneal haze and optical aberrations caused by the refractive laser procedure. Retinal reattachment was achieved in all 11 eyes though one eye required four surgical interventions. CONCLUSION: This is the first published report to describe an association between retinal detachment and previous excimer laser treatment. The association would appear to reflect the predisposition of myopes to retinal detachment. Clinicians should be aware of potential retinal pathology in patients undergoing PRK.

Multicenter clinical experience using an erbium:YAG laser for vitreoretinal surgery.

PURPOSE: To evaluate the advantages, disadvantages, safety, complications, and surgical applicability of an erbium:YAG laser system for maneuvers in vitreoretinal surgery. METHODS: A prospective, consecutive trial of 68 eyes in 66 patients undergoing vitreoretinal surgery in which an erbium:YAG laser with graduated output from 0.2 to 5.0 mJ per pulse, repetition rate of 2 to 30 Hz, and equipped with a flexible fiber optic and interchangeable 20-gauge intraocular fiber optic endoprobes was used to perform specific maneuvers, including transection, incision, and ablation of membranes, retinotomy, vessel coagulation, iridectomy, and lens tissue ablation. The patients were treated in five centers in contemporary vitreoretinal surgical settings for surgical indications, including proliferative diabetic retinopathy, proliferative vitreoretinopathy, epiretinal membrane, and retinopathy of prematurity. RESULTS: One hundred seventy-four maneuvers were performed with an overall surgical efficacy rating of excellent or good in 84% of maneuvers, ranging from a high of 100% for subretinal membrane transection to a low of 25% for coagulation of blood vessels. Complications included retinal break or photocoagulative injury in 5% of epiretinal membrane incisions, minor bleeding from transected retinal vessels during 29% of retinotomies, and intraocular lens damage during two posterior capsulotomies. The most significant limitation was the cautious pace used during maneuvers near the retinal surface. CONCLUSION: The erbium:YAG laser is capable of versatile new approaches offering precise tissue cutting and ablation in vitreoretinal surgical maneuvers with a high degree of safety. The main limitation encountered was the slow speed of certain critical maneuvers near the retina.

Implantation of foldable intraocular lenses in the presence of anterior capsular tears.

A consecutive series of patients who had undergone small-incision phacoemulsification cataract surgery with foldable lens implantation were reviewed. Seven patients had sustained anterior capsular tears during surgery. In all cases a three-piece foldable intraocular lens (IOL) was successfully inserted by careful positioning of the haptics. In all 6 patients available for long-term assessment the IOL remained stable and well centred, the tears having been sealed by fibrous tissue. We show that, if logical measures are taken to limit tear extension, the lack of an intact capsulorhexis need not result in conversion to extracapsular cataract extraction.

Combined peribulbar injection and blunt cannula infiltration for vitreoretinal surgery.

Seventy-six patients undergoing combined peribulbar and direct intraconal infiltration local anesthesia for vitreoretinal surgery were prospectively evaluated. Forty-six patients had local anesthesia with a combination of lidocaine 2% and bupivacaine 0.5%; in 30 patients, a combination of lidocaine 2% and prilocaine 1% was used. Patient evaluation of discomfort during the administration of the anesthetic and during the operation was assessed on a visual analog scale of 0 to 10. The mean pain score recorded was 2.73. There was no statistically significant difference between the mean pain scores of the two local anesthetic groups (P = .465).

Is surgery for proliferative vitreoretinopathy justifiable?

Surgery for proliferative vitreoretinopathy (PVR) may require prolonged procedures often with limited improvement in visual function. Forty-seven consecutive patients who had PVR surgery in one eye had a case note review to assess anatomical re-attachment rate and improvement in visual acuity. All patients had at least 3 clock-hours of grade C PVR membrane. Surgery comprised vitrectomy and membrane peel in all cases. There was a mean follow-up period of 9 months (range 3-23 months). Thirty-two eyes (68%) had an attached retina with the mean visual acuity being 0.089 (where 6/60 = 0.10). A mean of 2.15 PVR operations were performed per eye. Seventeen patients chosen at random were contacted by telephone and standardised questions were asked regarding their surgery. Eleven (65%) patients stated that, with the benefit of hindsight, they would still have had surgery and 8 (47%) patients stated that the peripheral vision gained was of benefit.

Suture needle drainage of subretinal fluid.

A simple technique is described for the transcleral drainage of subretinal fluid during retinal detachment repair. In a prospective study of 94 consecutive suture needle drainage procedures subretinal fluid was successfully drained in 91 cases. There were six 'significant' subretinal haemorrhages associated with the procedure, but none was subfoveal in location or directly compromised the surgical outcome. In no case was retinal incarceration or retinotomy observed.

Primary vitrectomy for rhegmatogenous retinal detachment.

One hundred and twenty-four eyes with a rhegmatogenous retinal detachment, considered to be at high risk of failure if treated conventionally, underwent vitrectomy and internal tamponade, with or without scleral buckling, as the primary procedure. The retina was reattached in 64.5% of eyes after one operation, 75.0% after two, and in 83% of eyes after more than two operations, with no difference in the success rate between those eyes which underwent vitrectomy alone, and those that received adjunctive scleral buckling; duration of surgery was significantly shorter, however, in the former group. Twenty percent of eyes redetached in association with proliferative vitreoretinopathy, and 20% of phakic eyes developed posterior subcapsular lens opacities after surgery. Vitrectomy is now an established method in the management of selected cases of rhegmatogenous retinal detachments.

Clinical risk factors for failure in glaucoma tube surgery. A comparison of three tube designs.

We studied a cohort of 165 eyes that had undergone tube implant surgery for glaucoma, with a minimum follow-up of 12 months (range, 12 to 72 months). Of the 57 cases (34.5%) in which surgery failed to control intraocular pressure (less than 22 mm Hg), 15 (26%) occurred by 3 months, 36 (63%) by 12 months, and 46 (80%) by 24 months. Cox regression modeling was used to evaluate independent risk factors in the absence of additional therapy. The use of a two-piece (anterior chamber-to-encircling band) tube system was associated with a 2.4 times higher risk of failure (P less than .001) compared with a one-piece system. Neovascular glaucoma was associated with a 2.1 times higher risk of failure (P less than .037) than other types of glaucoma. Late failure of tube implant surgery is common and there is a steady attrition rate over a 2-year follow-up period.

Mathematical modelling of retinal tear formation: implications for the use of heavy liquids.

When force is applied to detached retina it elevates, stretches, and becomes irreversibly deformed. Finally it tears, and the timing and location of tear formation are determined by the distribution of stress within the retina. This stress distribution is dependent upon the retinal contour. We have tested this using retinas of freshly enucleated bovine eyes. A suture was attached to isolated retinal tissue using butylacrylate (Histoacryl) glue and traction was applied to this suture so stretching the retina. We present a mathematical model of the in vitro data obtained, with predictions for local retinal internal tensions. We show that these are altered by the addition of hydrostatic forces due to the presence of heavy liquids. These findings have implications for epiretinal membrane dissection during surgery and for the use of heavy liquids during membrane peeling.

Symmetry of disciform scars in bilateral age-related macular degeneration.

The size of the final macular scar in subretinal neovascularisation (SRNV) is one of the most important determinants of final visual function in patients with subfoveal disease. We studied patients with bilateral macular scars from age-related subretinal neovascular membranes retrospectively in order to determine whether or not fellow eyes behave similarly. We found a significant correlation between eyes in terms of final scar size (r = 0.50, p less than 0.01). We found that 50% of fellow eyes with large macular scars (greater than 3 x 10(6) microns2) had similar sized lesions, while only 16% of fellow eyes with small macular scars (less than 0.5 x 10(6) microns2) had large scars (p less than 0.01). We discuss the significance of these findings in relation to the pathogenesis of subretinal neovascular membranes, and their implications for treatment.

The influence of prior therapy on the success of trabeculectomy.

The role of early surgery in the management of primary open angle glaucoma is under debate. To determine whether previous medical therapy influences the outcome of subsequent trabeculectomy, we retrospectively reviewed the results of surgery in two groups of patients. The first group underwent primary trabeculectomy, having had an average of 2 weeks of preoperative medical therapy, and this group was compared with a group of patients who had received at least 1 year of topical glaucoma therapy before undergoing trabeculectomy (the multiple-treatment group). The two groups were similar in terms of a number of variables, including race, age, sex, presenting intraocular pressures, and presenting visual fields, and they differed only in the known duration of their disease. The success rate of trabeculectomy was significantly higher in the primary trabeculectomy group as compared with that in the multiple-treatment group (P less than .001). We discuss the possible reasons for this difference and its implications for the future management of primary open angle glaucoma.