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Sanjeewa S Wickremasinghe

Publications and source records attributed to Sanjeewa S Wickremasinghe.

7 recordsLinked to original sources
PubMed2005

Accuracy of intraocular pressure measurements in new zealand white rabbits.

PURPOSE: Rabbits are commonly used for the evaluation of drugs and surgery to lower intraocular pressure (IOP). The accuracy of intraocular pressure measurement is therefore critical in the analysis of data and subsequent extrapolation to humans. The purpose of this study was to establish the most reliable technique, from several currently available methods, of measuring IOP in New Zealand White rabbits. METHODS: The IOPs of 11 healthy New Zealand White rabbits were measured with a fluid-filled pressure transducer system that was connected to the anterior chamber of each animal so that the IOP could be varied by altering the height of a bottle of balanced salt solution. Intraocular pressures were recorded over a range of 50 to 0 mm Hg by the transducer system, and comparative measurements at the same pressures were performed with the Tonopen XL (Mentor, Norwell, MA), the Perkins handheld applanation tonometer (Clement Clarke, Harlow, UK), and the Ocular Blood Flow (OBF) pneumatonometer (OBF Laboratories, Wiltshire, UK). RESULTS: All three tonometers underestimated the true IOP, especially at higher pressures. Although the mean difference in actual and tonometric IOP was least in the Tonopen XL, there was a high degree of variability through the entire range of IOPs measured. The Perkins tonometer, although slightly less accurate than the Tonopen XL, was more consistent in measurement. The OBF pneumatonometer was the least-reliable estimate of IOP. CONCLUSIONS: All tonometers underestimate IOP, with increasing inaccuracy at higher pressures. The Perkins applanation tonometer was the most reliable for measuring IOP in the range of 0 to 50 mm Hg in New Zealand White rabbits.

Animals↗
PubMed2003

Same-day versus first-day review of intraocular pressure after uneventful phacoemulsification.

PURPOSE: To compare the incidence and the spectrum of postoperative complications detected when the intraocular pressure (IOP) is reviewed 4 to 6 hours or the day after uneventful phacoemulsification cataract extraction and intraocular lens (IOL) implantation. SETTING: Royal Free Hospital, London, United Kingdom. METHODS: The study cohort consisted of 141 patients who had uneventful phacoemulsification and IOL implantation under regional (peribulbar/topical) or general anesthesia. Postoperative evaluation of the patients was performed by an ophthalmologist using a standard form at 4 to 6 hours or 24 hours. RESULTS: The mean IOP at 4 to 6 hours and 24 hours was 22.85 mm Hg +/- 9.56 (SD) and 19.44 +/- 7.04 mm Hg, respectively. The IOP was more likely to be greater than 30 mm Hg when measured on the same day, resulting in a significantly higher intervention rate than on the first day (P =.037). The best corrected visual acuity was significantly better at 24 hours than at the same-day review (P <.001). There was no significant difference in the extent of anterior chamber activity, patient comfort, or state of the wound between the same- or next-day follow-up. All patients attended a follow-up appointment 3 weeks after surgery, had an IOP of 21 mm Hg or less, and were subsequently discharged. CONCLUSIONS: The results indicate that moderate IOP spikes (<40 mm Hg) can be left untreated if they are not associated with corneal edema or patient discomfort as they decline spontaneously. Before they are discharged, patients with compromised optic discs or predisposed to retinal or optic nerve pathology should be carefully evaluated the day after surgery to treat IOP elevations.

Adolescent↗
PubMed2003

Efficacy of anterior chamber decompression in controlling early intraocular pressure spikes after uneventful phacoemulsification.

PURPOSE: To determine the efficacy of anterior chamber decompression in the management of intraocular pressure (IOP) spikes in the early period after uneventful phacoemulsification. SETTING: Royal Free Hospital, Department of Ophthalmology, Royal Free and University College London Medical School, London, United Kingdom. METHODS: This prospective case series comprised 11 consecutive patients with otherwise healthy eyes who an IOP of at least 40 mm Hg 4 to 6 hours after phacoemulsification. After anterior chamber decompression, the IOP was measured at 0, 15, 30, 45, and 60 minutes or until it exceeded 40 mm Hg. RESULTS: The mean IOP 4 to 6 hours postoperatively was 47.09 mm Hg +/- 7.92 (SD) (range 40 to 68 mm Hg). After decompression, the IOP dropped significantly to a mean of 4.73 +/- 3.00 mm Hg at 0 minutes (P<.001) and then increased progressively to 23.36 +/- 10.80 mm Hg at 15 minutes (P<.001), 33.82 +/- 11.74 mm Hg at 30 minutes (P=.005), 35.00 +/- 6.53 mm Hg at 45 minutes (P=.015), and 38.50 +/- 2.51 mm Hg at 60 minutes (P=.041). CONCLUSIONS: Marked IOP spikes developed in eyes without glaucoma or ocular hypertension after uneventful phacoemulsification. Anterior chamber decompression immediately lowered IOP, but the effect was transient.

Aged↗
PubMed2003

Visual perception during phacoemulsification cataract surgery under topical and regional anaesthesia.

PURPOSE: To compare the subjective visual experiences of patients during phacoemulsification and intraocular lens (IOL) implantation using regional and topical anaesthesia. DESIGN: A prospective, cohort, questionnaire-based study. METHODS: The study cohort consisted of 247 patients without pre-existing ocular pathology who underwent routine phacoemulsification and IOL implantation. The mean age of the subjects was 75.4 +/- 9.4 years and 34.5% of them had a history of cataract surgery. Three different methods of local anaesthesia were used: 66 (26.7%) of the patients were given topical anaesthesia (TA); 74 (30.0%) were given sub-Tenon's anaesthesia (SA), and 107(43.3%) were given peribulbar anaesthesia (PA). The patients were interviewed immediately after surgery by theatre staff using a standardized questionnaire that investigated their intraoperative visual experiences. RESULTS: There was no significant difference between the three methods of anaesthesia regarding light perception during the surgery. However, patients undergoing surgery under TA experienced brighter light intensity levels (78.3%) than those given SA (50.0%) and PA (55.7%) (p = 0.02). A total of 69.6% of subjects who received TA reported visual perception of colours during surgery, as opposed to 56.8% of SA recipients and 49.0% of PA recipients (p = 0.02). In addition, patients under TA were more aware of surgical instruments (26.1%) than those under SA (10.8%) and PA (15.9%) (p = 0.08). The vast majority of patients in all three groups found the visual experience to be non-frightening. There were no associations between intraoperative visual impression and age or sex. Although not statistically significant (p = 0.06), prior cataract surgery appeared to alleviate some of the anxiety associated with the visual experience. CONCLUSION: Patients undergoing regional and topical anaesthesia experience a wide variety of visual sensations during surgery. The differences in visual impressions between the groups may reflect the varying degrees of optic nerve blockade that result from the different anaesthetics.

Aged↗
PubMedDate not supplied

Macular edema.

Macular edema is the final common pathway of many intraocular and systemic insults. It may develop in a diffuse pattern where the macula appears generally thickened or it may acquire the characteristic petaloid appearance referred to as cystoid macular edema. Although macular edema may be associated with protean underlying conditions, it is most commonly seen following intraocular surgery, venous occlusive disease, diabetic retinopathy, and posterior segment inflammatory disease. As well as clinical suspicion, a wide range of investigations may lead to the diagnosis of macular edema. Fluorescein angiography and optical coherence tomography provide enhanced visualization of the geometry and distribution of macular edema. A variety of approaches to the treatment of macular edema have been attempted, with a variable degree of success. These options have included topical and systemic steroids, topical and oral non-steroidal anti-inflammatory agents and laser photocoagulation treatment. More recently other therapeutic modalities, including immunomodulators, intravitreal injection of triamcinolone, and pars plana vitrectomy have also been employed. Clinical trials are currently looking into the use of a steroid slow-release intravitreal device for the management of macular edema secondary to uveitis and diabetes. This article reviews the clinical entity of macular edema focusing on the current therapeutic strategies for its management.

Humans↗