Tin Aung

Subjective visual experience during phacoemulsification and intraocular lens implantation under topical anesthesia.

OBJECTIVEnThe aim of this study was to investigate the subjective visual experience of patients during phacoemulsification and intraocular lens (IOL) implantation under topical anesthesia.nnnDESIGNnPostoperative questionnaire survey.nnnPARTICIPANTSnThe study cohort consisted of 52 patients with cataracts. There were 18 male (34.6%) and 34 female (65.4%) patients. Their mean (+/- SD) age was 67.5 (+/-10.8) years.nnnINTERVENTIONnThe patients underwent routine phacoemulsification and IOL implantation under topical anesthesia.nnnMAIN OUTCOME MEASURESnThe patients were interviewed on the same day after their operation regarding their visual experience in the operated eye during surgery.nnnRESULTSnAll patients (100%) reported that they could see at least some light during the surgery. Some patients reported they could also see one or more colors (50 patients, 96.2%), movements (32 patients, 61.5%), flashes (24 patients, 46.2%), the surgeons fingers/hands (13 patients, 25%), instruments (12 patients, 23.1%), and/or the surgeon (4 patients, 7.7%). The colors seen included red (24 patients, 46.2%), yellow (23 patients, 44.2%), blue (12 patients, 23.1%), green (7 patients, 13.5%), and orange (6 patients, 11.5%). Eight patients (15.4%) saw the spectrum of colors similar to that of the rainbow. Twenty-four patients (46.2%) reported that the brightness of light changed during the course of the operation. Eight patients (15.4%) found their visual experience frightening. There was no statistically significant association between those who found the visual experience frightening and the sex or age of the patient, a history of cataract operation in the fellow eye, the type of visual sensation experienced, or the presence of coexisting ocular pathology.nnnCONCLUSIONnAll patients undergoing phacoemulsification under topical anesthesia experience a variety of visual sensations that may be frightening in a small proportion of patients.

Trabeculectomy for acute primary angle closure.

OBJECTIVEnTo analyze the results of trabeculectomy performed for all cases of acute primary angle closure (APAC).nnnDESIGNnRetrospective, noncomparative case seriesnnnPARTICIPANTSnFifty-six consecutive patients who underwent trabeculectomy for APAC at two Singapore centers from 1993 through 1995.nnnMETHODSnThe conventional treatment for APAC is to lower intraocular pressure (IOP) medically, after which laser peripheral iridotomy (PI) is performed. However, in Asian eyes, the acute attack is often refractory to standard treatment. Trabeculectomy is occasionally performed on eyes that do not respond to medical therapy, as well as eyes with APAC that respond to medical therapy but are assessed as having underlying chronic angle-closure glaucoma. In such cases, laser PI is not performed before trabeculectomy.nnnMAIN OUTCOME MEASURESnThe surgical outcome was assessed in terms of final IOP and the incidence of complications. Success was defined as final IOP less than 21 mmHg without medication, and qualified success was defined as final IOP less than 21 mmHg with medication. Patients whose IOP was more than 21 mmHg, required further glaucoma surgery, lost light perception, or whose eye became phthisical were classified as failures.nnnRESULTSnThe mean follow up was 22 months (range, 6-42 months). In group A, the medical failure group (n = 32), success in IOP control was obtained in 18 patients (56.2%), qualified success was achieved in 3 patients (9.4%), and failure resulted in 11 patients (34.4%). Ten patients (31.3%) encountered early postoperative complications such as shallow anterior chamber. In group B, the medical success group (n = 24), success in IOP control was achieved in 21 patients (87.5%), qualified success was achieved in 3 patients (12.5%), and there were no cases of failure. The incidence of postoperative complications was low (4 eyes [16.7%]). In terms of IOP outcome, trabeculectomy outcome was significantly worse in group A (P<0.001, Fishers exact test).nnnCONCLUSIONSnBecause there is a high risk of surgical failure and complications, trabeculectomy may not be the procedure of choice in medically unresponsive cases of APAC.

Comparison of the intraocular pressure-lowering effect of latanoprost and timolol in patients with chronic angle closure glaucoma: A preliminary study

OBJECTIVEnTo compare the intraocular pressure (IOP)-reducing effect and side effects of 0.005% latanoprost once daily to 0.5% timolol twice daily in patients with primary chronic angle closure glaucoma (CACG).nnnDESIGNnRandomized, double-masked two-center clinical trial.nnnPARTICIPANTSnThirty-two Asian patients with CACG, defined as glaucomatous optic neuropathy with a compatible visual field defect and at least 6 clock hours of synechial angle closure on gonioscopy were recruited. All patients had previous peripheral iridotomy (PI) with IOP >21 mmHg after PI and were thereafter controlled (IOP <22 mmHg) with one or two pressure-reducing drugs.nnnINTERVENTIONnAfter a washout period, the patients were randomized to a 2-week treatment period with either placebo in the morning and 0.005% latanoprost in the evening or 0.5% timolol twice daily.nnnMAIN OUTCOME MEASURESnThe short-term IOP reduction of latanoprost and timolol in patients with CACG. IOP was measured at baseline, and after 2, 7, and 14 days of treatment. In addition, the short-term ocular and systemic adverse events of the two drugs were evaluated.nnnRESULTSnThirty patients completed the study. Two patients in the timolol group were withdrawn because of inadequate IOP control. Compared with baseline, the IOP after 2 weeks of treatment was statistically significantly reduced by 8.8 +/- 1.1 mmHg (mean +/- SEM, P < 0.001) in the latanoprost group, and by 5.7 +/- 0.9 mmHg (P < 0.001) in the timolol group. The difference in IOP reduction between the two treatment groups was 3.1 +/- 1.5 mm Hg in favor of latanoprost (P = 0.04). The main ocular adverse events reported in both treatment groups were conjunctival hyperemia and discomfort.nnnCONCLUSIONSnIn this preliminary study, a significantly greater IOP reduction was achieved with 0.005% latanoprost once daily compared with 0.5% timolol twice daily in patients with CACG. The results suggest that latanoprost may be a therapeutic choice for the medical treatment of primary CACG.

Glaucoma drainage implants in Asian eyes

OBJECTIVEnPrevious studies have suggested that there are racial differences in the outcome of conventional filtration surgery. This study aims to evaluate the outcome of glaucoma drainage implants in Asian eyes with complicated glaucoma and to determine whether there are racial differences in the results of such implant surgery compared to previous reports in non-Asian patients.nnnDESIGNnThe study design was a retrospective review of all patients with more than 6-months follow-up after glaucoma implant surgery at the Singapore National Eye Centre between January 1993 and August 1996.nnnPARTICIPANTSnA total of 83 Asian patients with uncontrolled complicated glaucoma participated.nnnINTERVENTIONnA total of 29 patients received Molteno implants and 54 received Baerveldt implants.nnnMAIN OUTCOME MEASURESnThe surgical outcome was assessed in terms of final intraocular pressure (IOP), visual acuity outcome, and incidence of complications. Success was defined as final IOP less than 22 mmHg with no medications and qualified success as an IOP less than 22 mmHg with medication.nnnRESULTSnWith mean follow-up of 13.41 months, success in IOP control was achieved in 73.5% of patients and qualified success in 12%. Visual acuity remained stable or improved in 85.5%. There were no patients who encountered intraoperative complications, and the incidence of serious postoperative complications was low. The most frequently observed short- and long-term postoperative complication was hyphema in 14 eyes (16.9%) and bullous keratopathy in 7 eyes (8.4%), respectively.nnnCONCLUSIONSnGlaucoma drainage implants have good outcome and visual stabilization in Asian eyes with success rates for IOP control comparable to those reported in previous studies in non-Asian eyes.

Indirect gonioscopy system for imaging iridocorneal angle of eye

Current clinical optical imaging systems do not provide sufficient structural information of trabecular meshwork (TM) in the iridocorneal angle (ICA) of the eye due to their low resolution. Increase in the intraocular pressure (IOP) can occur due to the abnormalities in TM, which could subsequently lead to glaucoma. Here, we present an indirect gonioscopy based imaging probe with significantly improved visualization of structures in the ICA including TM region, compared to the currently available tools. Imaging quality of the developed system was tested in porcine samples. Improved direct high quality visualization of the TM region through this system can be used for Laser trabeculoplasty, which is a primary treatment of glaucoma. This system is expected to be used complementary to angle photography and gonioscopy.