European Journal of Implant and Refractive Surgery最新文献

OBJECTIVES: To demonstrate that cataracts with small pupils should be operated on by phacoemulsification. Thirty-five eyes with a pupil diameter of less than 3 mm at the beginning of the procedure were reviewed. They were compared with 48 eyes with small pupils, operated by extracapsular cataract extraction (ECCE) with iridoplasty during the period 1990–1992. SETTING: Eye Clinic, University of Verona, Italy. MAIN OUTCOME MEASURES: Clear corneal incisions were adopted. Viscoelastic (Healone®) was used to enlarge the pupil. Intraoperative and postoperative complications were analysed. RESULTS: In 5 eyes (14%) a rupture of the capsulorhexis developed. In one eye the tear extended to the posterior capsule. In 4 eyes (11%) the iris was caught by the phaco-tip, which was connected to a diaphragmatic pump. Damage to the iris from the sleeve of the phaco-tip was observed in 20 eyes. Postoperatively, a fibrinous reaction developed in 11 eyes, lasting 7–10 days. CONCLUSIONS: Eyes with small pupils are most frequently eyes treated by miotics for glaucoma. For these eyes, clear corneal incision and phacoemulsification seems preferable to ECCE with iridoplasty.

OBJECTIVE: To establish an unambiguous method to assign A-constants and similar constants required by the various formulas in use for the calculation of intraocular lens (IOL) implant power, without recourse to clinical investigations. METHOD: Retrospective analysis of clinical data involving widely different IOL designs and several surgeons was performed to find the position of the lens haptic plane (LHP). The clinical data had been generated previously for entirely different purposes. Inclusion criteria were visual acuity of 0.5 (20/40) or better and availability of a postoperatively (3-12 months) measured ACD (distance from anterior cornea to anterior IOL). Ray-tracing calculations were performed to find the ACD compatible with the optical data (preoperative L and K, and IOL power). The exact design (front and back radii, and central thickness) of the IOL was used in these calculations. The calculated ACD was verified against the postoperatively measured ACD. Lens haptic plane was calculated from ACD using the geometry of each particular design. RESULTS: Data from 688 cases, 8 different clinics and 4 IOL models were analysed. On average the calculated ACD coincided with the postoperatively measured ACD when applying paraxial ray-tracing and thick lens theory (Gaussian optics). An average eye with K = 43.63 D, L = 23.24 mm and LHP = 4.02 mm was established. For any new IOL design, the power to make this average eye emmetropic can be determined by applying paraxial ray-tracing. Subsequently the A-constant or any other formula constant can be determined. LEMMA: There is no need to utilize constants inherent to various formulas. The calculation model used to find the constants could just as well be used directly to find the exact implant power, provided that the position of the LHP is known and that the manufacturer supplies the necessary design information. Because the LHP concept is independent of IOL model, the advantage would be that the surgeon could concentrate on refining his technique to estimate LHP preoperatively, rather than personalizing constants for every new IOL model.

OBJECTIVE: While 3.5 mm clear corneal incisions for the implantation of foldable silicone lenses are commonly accepted, longer incisions for PMMA-IOL implantation are associated with a possibly higher risk of infection and less self-sealing properties. DESIGN: It was intended to reinforce the 5 mm clear corneal tunnel incision after phacoemulsification and IOL-implantation with fibrin adhesive. SETTING: Department of Ophthalmology, University of Giessen, Germany. METHODS: Upon simultaneous mixing of fibrinogen complex and thrombin, the final stages of the coagulation cascade are mimicked after application of fibrin glue, resulting in formation of a fibrin clot. MAIN OUTCOME: The sealant consolidated and adhered to the site of corneal application. The present case demonstrated that fibrin glue is efficacious in watertight wound closure of 5 mm clear corneal incision and provides good support for corneal healing. Only minimal surgically-induced with-the-rule astigmatism was observed. CONCLUSION: In the future, this technique of corneal wound closure might develop as an alternative to singlesuture wound closure after small incision cataract extraction.

OBJECTIVE: Quantitative assessments of in vivo endothelial cell density, size and shape after cataract surgery provide an important tool for control of surgical quality. To investigate reproducibility, quality and advantages or disadvantages of individual specular micrographs obtained with a non-contact microscope, endothelial cell parameters were compared with micrographs obtained with a contact specular microscope. STUDY DESIGN: Five photographs of the central cornea of 24 eyes (17 patients) 6 months after clear-corneal cataract surgery were assessed by non-contact, using the zoom mode, and contact specular microscopy, respectively. After qualitative morphological and quantitative morphometric analysis of the 240 photographs, data of both methods were compared. SETTING: Department of Ophthalmology, Giessen, Germany. MAIN OUTCOME: Image analysis of different cell parameters showed a few significant differences in both methods: Intraphotographic analysis showed no significant coefficient variation of mean cell parameters, while interphotographic analysis detected a significantly higher spread of many values, such as cell density and area in non-contact specular microscopy. The rate of obtaining endothelial images was very successful. CONCLUSIONS: The clinical advantages of the non-contact instrument are the high successful rate of taking images with safety and useful reproducibility. The smaller field obtained with the noncontact system allows estimation of endothelial morphological and quantitative parameters. More detailed information and precision of the posterior endothelial surface was provided by the contact specular microscope.

OBJECTIVE: To determine whether lateral no-stitch cataract incision can reduce pre-existing against-the-rule astigmatism. STUDY DESIGN: Prospective study of change in keratometric astigmatism after standardized lateral 6 mm no-stitch scleral frown incision technique. One week and 3 months postoperatively, visual acuity, refraction (Canon RK II) and keratometry (Zeiss Ophthalmometer) were evaluated. SETTING: University Eye Hospital of Homburg, Saar, Germany. PATIENTS: Twenty-two eyes and patients were included in the study. RESULTS: The magnitude of the keratometric astigmatism was significantly (P < 0.01) less after 1 week and 3 months. There was no great shift of induced astigmatism between 1 week and 3 months. CONCLUSIONS: The results demonstrate that pre-existing against-the-rule astigmatism can be significantly reduced by placing the no-stitch cataract incision temporally at the steep astigmatism meridian.

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.

OBJECTIVE: To undertake a comparative study of endothelial cell loss after 3.5 mm temporal clear corneal incisions (tCCI) and 3.5 mm superior scleral tunnel incisions (sSTI). STUDY DESIGN: Besides the site and preparation of the incision all 59 eyes were operated with the same surgical technique and implantation of a flexible silicone intraocular lens (IOL) through a 3.5 mm incision. In group 1 a temporal clear corneal incision and in group 2 a superior scleral tunnel incision were prepared. Endothelial cell density was measured preoperatively and 6 months after surgery with a contact specular microscope (Konan®). The results were compared and statistically analysed. RESULTS: Mean endothelial cell loss was 8.1% in group 1 and 3.0% in group 2. Even though relevant differences were found between the 2 groups, in statistical analysis the significance was ‘borderline’ (P < 0.0964). CONCLUSIONS: Even though CCI is a promising surgical technique with high beneficial influence on surgery and postoperative outcome, an increased central endothelial cell loss may be expected after surgery. Because of this fact, in the opinion of the authors, this technique should be avoided in cases with very hard cataracts and/or in cases with low preoperative endothelial cell density. As shown in the literature, when performing a CCI it is advisable to create the incision at the temporal site and not at the superior site which is close to the central corneal region.

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.