OBJECTIVES: Retrospective review of 41 patients who underwent simultaneous bilateral phacoemulsification to establish (1) perceived low complication rate, (2) early binocular visual rehabilitation, (3) lower financial costs in terms of nursing care, bed occupation, short stay and fewer out-patient visits needed postoperatively. MAIN OUTCOME MEASURES: (1) Incidence of intruoperative and postoperative complications, (2) final visual acuity and refraction as compared with initial state, (3) time from operation to final refraction. RESULTS: There were no cases of conversion from phacoemulsification. Ninety-two per cent of patients had a final corrected visual acuity of 6/12 or better with minimal anisometropia. Surgical induced astigmatism was 1.4 D at 2 weeks and 0.97 D at final refraction. The mean final refraction was at 9 weeks postoperation. CONCLUSION: Simultaneous bilateral phacoemulsification is a safe, efficient procedure. There are benefits to the patient, surgeon and administration in terms of time and resources. The patient is saved from double preoperative stress, 2 general anaesthetics, time in hospital is shortened and binocular visual rehabilitation is achieved early. Administrative authorities welcome the economy in operative time, anaesthetic time, nursing care and bed occupation.
Removal of the cataractous lens is now a much more complex process than in the days of intracapsular surgery, and indeed more complex than the techniques employed during the early development of phacoemulsification. Understanding how the phacoemulsification machine can be adjusted to maximize safety and effectiveness during the different stages of the modern operation should enable the surgeon and the patient to enjoy a more effective procedure. Some understanding of the basic principles ofphaco machines has been given elsewhere [1], and here the author intends to indicate how these principles can be put into practice.
OBJECTIVE: To compare the degradation properties of nylon and polyester (Mersilene) sutures using scanning electron microscopy (SEM). STUDY DESIGN: Sutures which were removed on clinical grounds for the correction of astigmatism at 6 and 12 months postoperatively following routine extracapsular cataract extraction were studied under SEM. RESULTS: Progressive disintegration of nylon sutures over the study period. Mersilene appeared to maintain its structural integrity. CONCLUSIONS: SEM confirms clinical studies that Mersilene sutures remain intact and so are less likely to cause late complications when left in situ.
This article is the seventh in a series which describes the role of computerized videokeratoscopy and highlights its value in different clinical settings. It illustrates and describes the variety of topographic patterns seen with corneal disease. Essentially, there are 3 basic mechanisms by which pathological processes can disrupt the surface topography of the cornea. These include abnormalities of the epithelium, degradation of the stroma and external compression from lid or orbital masses. With the advent of computerized videokeratoscopy, we can now easily detect and quantify such abnormalities. The mechanisms by which corneal disease effects changes in the corneal topography are illustrated and discussed. The possible clinical applications of videokeratoscopy in the management of corneal disease are reviewed.
Techniques for assessing corneal topography have been developed and improved over the last four centuries in response to changing demand. In recent years, there has been an escalation in the number, type and complexity of the systems available, following a trend which may continue into the future. Most widely-available topography systems are based on the principle of reflection (videokeratoscopy), although there is now an increasing number of systems based on the principle of projection (rasterstereography, moiré interference and laser interferometry). Each technique has its own inherent advantages and limitations. For example, those based on projection can directly measure true corneal height and be used in the individualized treatment of irregular corneal astigmatism. Most systems rely upon computer algorithms to convert recorded images into topographic information. New algorithms incorporating fewer estimates and assumptions are being developed, in order to improve the accuracy with which the corneal surface can be reconstructed. The topographic data of individual patients can be displayed visually in the form of maps, but the need to analyse grouped data has lead to the development of quantitative descriptors of corneal shape, and indices predicting visual function. Classifications of normal and abnormal topography based on pattern recognition have been described, but await improvements in artificial neural networks before they can be automated. Advanced computing is also needed before data analysis is sufficiently rapid for real-time topography to become a reality. Future developments in corneal topography need to target the differing requirements of research and clinical practice.
Videokeratoscopy has proved an invaluable clinical tool in allowing a better understanding of corneal topography and how this varies in the general population. Its value is significant in the area of refractive surgery and in the diagnosis and monitoring of some corneal disorders. A further potential application of videokeratoscopy is in the area of contact lens fitting and after care, and some systems already include a contact lens module in their software. The software can show the contact lens to cornea fitting relationship in a number of ways and can store and present both clinical information and contact lens data which is helpful to the practitioner. This article reviews the means by which the systems may help the clinician working in the area of contact lens fitting and follow-up care.
This article is the sixth in a series which describes the role of corneal topography and highlights its value in different clinical settings. It illustrates and describes the variety of topographical patterns seen in keratoconus. The importance of screening for sub-clinical cases prior to refractive keratoplasty and the development of software and statistical indices designed to detect, diagnose and monitor the progression of the disease are discussed. The article illustrates the limitations of placido-disc based systems in obtaining accurate information in severely affected eyes with surface irregularities. The possible clinical applications of videokeratoscopy in the management of keratoconus are reviewed.
OBJECTIVE: The objective of the study was to compare the inflammatory reaction following cataract surgery in patients with diabetes and/or glaucoma implanted with heparin surface modified (HSM) or PMMA intraocular lenses (IOLs). Specular microphotography and slit lamp evaluation were used to determine the presence of foreign body giant cells and cellular deposits on the IOL surface. The presence of capsular fibrosis, pigment and fibrin or fibrinlike deposits determined by slit lamp were secondary efficacy variables. STUDY DESIGN: The study was performed as a prospective, randomized, double-blind, multi-independent clinical trial with 1 year follow-up. PATIENTS: The study comprised 239 patients with diabetes and/or glaucoma. Of these patients, 122 had diabetes, 103 patients had glaucoma, and 14 patients had both diabetes and glaucoma. The mean age of the patients was 73 (± 9.8) years. RESULTS: At all visits, including the 1 year visit, there was a statistically significant difference in favour of HSM with a lower percentage of patients having giant cells on the IOL surface in the HSM group. Cellular deposits, seen with the slit lamp, were also found in significantly fewer patients in the HSM group at all follow-up visits except at 1 week. Visual acuity, at 1 year, was ≥ 0.5 (20/40) in 72% of the HSM group and in 84% of the PMMA group. The reason for a visual acuity below 0.5 was in most cases related to preoperative pathologies, especially in the diabetic patients in the HSM group. CONCLUSION: The results of this study indicate that heparin surface modification increases the biocompatibility of PMMA IOLs by significantly reducing the postoperative foreign body reaction for at least 1 year following cataract surgery in patients with diabetes and/or glaucoma.
A case of acute onset calcific band keratopathy in a patient with severe dry eyes is described. Calcific bands appeared on 2 different occasions within 72 h of commencement of steroid eye drops. The possible aetiological role of phosphate-containing steroid drops in this condition is discussed. Usage of acetate rather than phosphate-containing steroid eye drops is suggested in patients with the predisposing factors for band keratopathy.
Objective: To assess postoperatively the position of the haptics of the scleral fixated posterior chamber intraocular lenses (IOLs), in order to improve precision in scleral fixation. Study Design: A number of 12 patients (16 IOLs) were studied postoperatively by ultrasound biomicroscopy (UBM). The STC-6 straight needle was used for scleral fixation, with different techniques. In addition, 8 aphakic eyes selected for secondary implantation were studied. Setting: University Eye Clinic, Verona, Italy. Main Outcome Measures: The position of the loops in the suture of the scleral fixation was determined. This position was related to the surgical technique and to the distance between the emergence of the sutures and the limbus. The status of the posterior chamber was studied in aphakic eyes. Results: Out of the 32 loops, 24 were located in the pars plana, 6 were located in the ciliary sulcus, and 2 were located in the iris root. After ab interno fixation (9 eyes), with a suture to limbus distance of 2–3 mm, all but 2 loops were posterior to the ciliary sulcus. After ab externo fixation (7 eyes), with a suture to limbus distance of 1.5–2 mm, 6 loops were in the pars plana, 6 were in the ciliary sulcus and 2 loops were against the iris root. Most aphakic eyes showed some anatomical impairment of the posterior chamber. One eye showed ciliary body detachment. Conclusions: Suture to limbus distances of about 1 mm should be adopted for scleral fixation. Reversed fornix based scleral flaps could improve precision. However, we must emphasize that posterior synechiae or ciliary processes may obstruct the access to ciliary sulcus in aphakic eyes. The UBM study is very useful in eyes selected for secondary implantation.
Spontaneous dislocation of the lens results from intraocular disease giving rise to mechanical stretching, inflammatory destruction or degeneration of the zonule. Degeneration of the zonule occurs particularly with hypermature cataract, high myopia or retinal detachment, but it is also a well-recognized condition associated with pseudoexfoliation syndrome (PES). Lens dislocation during cataract surgery in PES and spontaneous subluxation of the lens associated with PES have been previously reported. We describe a case of spontaneous complete dislocation of the lens in PES.
Objective: To compare the space maintaining capacity of Healon® and Healon® GV in the anterior chamber and capsular bag during implantation of a soft intraocular lens (IOL). Study Design and Patients: Fifteen patients undergoing phacoemulsification and soft IOL implantation were randomized to have either Healon® or Healon® GV during surgery. All patients were operated with scleral tunnel incision, capsulorhexis, posterior chamber phacoemulsification, widening of the incision to 4.0 mm and implantation of a folded silicone IOL with 6.0 mm optic (SI18NB), using a prodigy inserter. Setting: S:t Erik's Eye Hospital, Stockholm, Sweden. Main Outcome Measures: Qualitative evaluation of space maintaining capacity of the anterior chamber and ability to widen the capsular bag during soft IOL implantation. Intraocular pressure (IOP). Results: The space maintaining capacity was significantly better with Healon® GV than with Healon® both in the anterior chamber (P = 0.03) and in the capsular bag (P = 0.02). There was no significant difference in postoperative IOP Conclusions: The use of Healon® GV leads to better maintenance of space within the eye and potentially increased safety during soft IOL implantation.
OBJECTIVES: To evaluate prospectively the effect of a modified capsulorhexis technique on the degree of intraocular lens (IOL) centration in patients undergoing extracapsular cataract extraction (ECCE). Patients were randomized to have envelope capsulotomy (EC) in group 1 or a continuous circular capsulorhexis (CCC) with 1 relieving anterior capsule incision at 11 o'clock in group 2. STUDY DESIGN: Prospective study. SETTING: Liverpool, District general hospital. MAIN OUTCOME MEASURES: Observed mean optic decentration and maintenance of capsular fixation in both groups after a mean of 12.7 months follow-up. RESULTS: Mean optic decentration was 0.51 mm in group 1(26 eyes) as compared to 0.19 mm in group 2 (28 eyes). This was statistically significant (2-sample t-test, t = 3.045, 38 d.f., P = 0.0042). Loss of capsular fixation was observed in 5 eyes (20%) in group 1 where a haptic migrated superiorly out of the capsular bag. CONCLUSIONS: Excellent IOL centration is achieved by using this modified CCC technique. A relieving incision prevents inadvertent intracapsular delivery of the lens and the superior location of the incision facilitates ‘in-the-bag’ placement of the IOL with the haptics orientated to the 3 and 9 o'clock positions. This safe modified CCC technique is well suited for routine ECCE.
Aim: To describe a new device, the Maastricht topographer (MT), which uses the principle of moire interference, to measure corneal shape. Methods: The Maastricht Topographer (MT) projects two sinewave gratings onto the tearfilm in quick succession, and by local analysis of grating intensity in the image so formed, reconstructs the true corneal shape in terms of height from a reference plane. A total of 262 144 data points are measured in an area 21.5 × 14.5 mm. During a one year period, patients referred for topography had measurements made by the MT and a videokeratoscope. Three cases were selected to demonstrate the advantages of the MT. Results: Image acquisition by the MT was straightforward, with alignment and focusing being of less importance than in videokeratoscopes. It provided detailed topographic information from the whole corneal area, and from irregular or non-reflective surfaces. The initial reconstruction of the true corneal shape was expressed in terms of height, from which measurements of slope, curvature and power were derived directly. Conclusions: Height reconstructions made by the MT are particularly useful in certain corneal pathologies and in evaluating the corneal profile after photorefractive keratectomy. Measurement of the ablation surface immediately postoperatively is essential in the study of ablation profiles and postoperative wound healing.
