To compare the 2-year efficacy of phacoemulsification and intraocular lens implant (phaco/IOL) with laser peripheral iridotomy (LPI) in the early management of acute primary angle closure (APAC) and ...coexisting cataract.
Randomized, controlled trial.
We included 37 subjects presenting with APAC who had responded to medical treatment such that intraocular pressure (IOP) was ≤30 mmHg within 24 hours, and had cataract with visual acuity of ≤6/15.
The primary outcome measure was failure of IOP control defined as IOP between 22 to 24 mmHg on 2 occasions (readings taken within 1 month of each other) or IOP ≥25 mmHg on 1 occasion, either occurring after week 3. Secondary outcome measures were complications, degree of angle opening, amount of peripheral anterior synechiae, visual acuity, and corneal endothelial cell count (CECC).
Subjects were randomized to receive either LPI or phaco/IOL in the affected eye within 1 week of presentation and were examined at fixed intervals over 24 months. Patients underwent a standardized examination that included Goldmann applanation tonometry, gonioscopy, and CECC measurements. Logistic regression was used to estimate the effect of treatment on failure of IOP control. Time to failure was evaluated using the Kaplan-Meier technique and Cox regression was used to estimate the relative risk of failure.
There were 18 patients randomized to LPI and 19 to phaco/IOL. The average age of subjects was 66.0±9.0 years and mean IOP after medical treatment was 14.5±6.9 mmHg. The 2-year cumulative survival was 61.1% and 89.5% for the LPI and phaco/IOL groups, respectively (P = 0.034). There was no change in CECC for either group from baseline to month 6. There was 1 postoperative complication in the phaco/IOL group compared with 4 in the LPI group (P = 0.180).
Performed within 1 week in patients with APAC and coexisting cataract, phaco/IOL resulted in lower rate of IOP failure at 2 years compared with LPI.
To investigate the variation in macular retinal thickness in otherwise normal young Asian myopic subjects by using optical coherence tomography (OCT).
One hundred thirty ophthalmically normal men 19 ...to 24 years of age with myopia (spherical equivalent, -0.25 to -14.25 D) underwent examination of one randomly selected eye. Visual acuity, refraction, slit lamp examination, applanation tonometry, gonioscopy, A-scan ultrasound, fundus examination, visual field testing, and optic disc photography were performed. Exclusion criteria were visual acuity worse than 20/30, previous intraocular surgery, intraocular pressure >21 mm Hg, or other ocular diseases. Three horizontal transfixation and three vertical transfixation OCT scans (ver.4.1; Carl Zeiss Meditec, Dublin, CA) of 6 mm each were conducted on each eye by a single operator. Neurosensory retinal thicknesses at 100 points along each scan were measured, and the overall average, maximum, and minimum retinal thicknesses were analyzed by simple linear regression and analysis of variance.
The average macular retinal thickness (overall) was 230.9 +/- 10.5 microm and was not significantly related to the degree of myopia. The mean maximum retinal thickness (at the parafovea) was 278.4 +/- 13.0 microm, and correlated negatively with axial length (P = 0.03). The mean minimum retinal thickness (at the foveola) was 141.1 +/- 19.1 microm, and this was positively correlated with axial length (P = 0.015) and spherical equivalent (P = 0.0002). The retina was thicker at the superior and nasal parafovea compared to the inferior or temporal parafovea.
Average retinal thickness of the macula does not vary with myopia. However, the parafovea was thinner and the fovea thicker with myopia.
To prospectively quantify changes in anterior segment morphology after laser iridotomy using gonioscopy and ultrasound biomicroscopy (UBM).
Prospective comparative observational case series.
...Fifty-five fellow eyes of patients presenting with acute primary angle closure (APAC).
The fellow eyes of patients presenting with APAC were examined with UBM, A-scan ultrasonography, and optical pachymetry at presentation and 2 weeks after sequential argon/neodymium yttrium–aluminum–garnet laser peripheral iridotomy (LPI). UBM images were analyzed using UBM Pro 2000 software. Baseline measurements were made both under standard lighting conditions and in darkness to look for changes in anterior segment findings.
The degree of angle opening was measured using the angle-opening distance (AOD) at 250 and 500 μm from the scleral spur (AOD250 and AOD500, respectively) and angle recess area (ARA).
Fifty-five Asian patients were examined; AOD250, AOD500, and ARA all significantly increased after sequential laser iridotomy (
P < 0.002). Gonioscopic grading of the angle opening significantly increased in all 4 quadrants (
P < 0.001). The Van Herick grade of limbal anterior chamber depth increased (
P < 0.001), whereas the number of eyes classified as occludable decreased (73%–33%,
P < 0.001). Anterior chamber depth did not change significantly (2.41 mm ± 0.28 mm vs. 2.42 mm ± 0.30 mm,
P = 0.43) as measured with optical pachymetry. Increased illumination increased the angle-opening measures, but induced a different alteration in peripheral iris morphology. Illumination-induced changes were greater after iridotomy than before laser treatment.
In Asian eyes at high risk of developing APAC, sequential LPI produced a significant widening of the anterior chamber angle without deepening the anterior chamber centrally. LPI produces changes in iris morphology that are different from those caused by an increase in illumination, indicating that different mechanisms account for angle opening under these 2 conditions.
To examine the association of optic disk ovality with myopic refractive error, axial length, and the visual field.
Prospective observational case series.
The study included 150 randomly recruited ...male subjects with myopia. In all cases, one eye was randomly selected, and subjective refraction, slit-lamp examination, applanation tonometry, gonioscopy, A-scan ultrasonography, funduscopy, and color optic disk stereo photography were performed. Disk ovality was assessed using the ratio of minimum to maximum disk diameter (index of tilt). A ratio of ≤ 0.8 was considered as significant disk tilt. Visual fields were tested using static automated threshold perimetry with two methods of optical correction: trial lenses and contact lenses.
Of the total sample, 137 subjects completed the study. Mean age was 21.2 ± 1.1 year, and mean spherical equivalent was -6.36 ± 3.56 diopters. Mean ovality ratio was 0.83 ± 0.09; 55 subjects (40.2%) had significant tilted optic disks. Greater optic disk ovality (tilt) correlated with greater myopia (
P = .009) and longer axial length (
P = .009); 95.6% of subjects had normal visual fields with both methods of optical correction. Using multiple linear regression analysis, greater tilt was independently related to a higher mean defect on testing with trial lenses (
P < .01).
Increased optic disk tilt was associated with higher myopia and reduced sensitivity on field testing. These factors are important in the assessment of glaucoma in patients with myopia.
To assess the screening effectiveness of 3 new noncontact devices, the scanning peripheral anterior chamber depth analyzer (SPAC) (Takagi, Nagano, Japan), which measures peripheral anterior chamber ...depth (ACD); IOLMaster (Carl Zeiss Meditec, Jena, Germany), which measures central ACD; and Visante anterior segment optical coherence tomography (AS-OCT) (Visante, Carl Zeiss Meditec, Dublin, CA), which images the angles, and to compare these instruments with gonioscopy in identifying people with narrow angles (NAs).
Cross-sectional, observational, community-based study.
Phakic subjects aged >or=50 years without ophthalmic symptoms who were recruited from a community polyclinic in Singapore.
All subjects underwent examination with SPAC, IOLMaster, and AS-OCT in the dark by a single operator. Gonioscopy was performed by an ophthalmologist masked to the instruments' findings. The area under the curve (AUC) receiver operating characteristic (ROC) was generated to assess the performance of these tests in detecting people with a NA in either eye.
Eyes were classified as having NAs by gonioscopy if the posterior pigmented trabecular meshwork could be seen for <or=2 quadrants of the angle circumference with or without peripheral anterior synechiae.
A total of 2052 subjects were examined and underwent all 3 tests. The prevalence of a NA in at least 1 eye diagnosed by gonioscopy was 20.4% (422 subjects). The AUC for the SPAC using a numeric grade <5 as a cutoff was 0.83 (95% confidence interval CI, 0.82-0.85), with a sensitivity of 90.0% (95% CI, 86.8-92.7) and a specificity of 76.6% (95% CI, 74.4-78.6). The AUC for the IOLMaster at an ACD cutoff of <2.87 mm was 0.83 (95% CI, 0.81-0.85), with a sensitivity of 87.7% (95% CI, 84.2-90.7) and a specificity of 77.7% (95% CI, 75.6-79.7). The AUC for the AS-OCT was 0.76 (95% CI, 0.74-0.78), with a sensitivity of 88.4% (95% CI, 84.9-91.3) and a specificity of 62.9% (95% CI, 60.5-65.2).
The low specificity found with the SPAC, IOLMaster, and AS-OCT may limit the usefulness of these devices in screening for NAs.
To assess the performance of peripheral and central anterior chamber depth (ACD) measurements, and autorefraction, in identifying Chinese people with occludable drainage angles or established primary ...angle closure.
Population-based cross-sectional analysis.
Subjects aged 40 years and older were drawn from a representative sample of Chinese Singaporean residents. Limbal chamber depth (LCD) was estimated and central ACD was measured using optical pachymetry and ultrasound. An autorefraction was taken for all subjects. Angle width and the presence of peripheral anterior synechiae were determined by gonioscopy. Receiver operating characteristic curves were generated to show the performance of these tests in detecting occludable angles.
A total of 1090 subjects were examined. The prevalence of occludable angles was 6.5%. LCD measurement performed best in detecting occludable angles (area under the curve AUC 0.904, 95% confidence interval CI 0.870, 0.937). Optical pachymetry and ultrasound measurement of ACD performed less well (AUC 0.859 and 0.810, respectively), and autorefraction performed poorly in detecting occludable angles (AUC 0.632). LCD also gave the best performance in detecting primary angle closure (AUC 0.782, 95% CI 0.727, 0.837).
Limbal LCD estimation outperforms other methods of measuring ACD as a screening tool for the detection of occludable drainage angles in the Chinese population of Singapore.
To report 3-year results of a randomized, controlled trial comparing the use of a single application of 5-fluorouracil (5-FU) with placebo in trabeculectomy surgery.
Prospective, randomized, ...double-blinded treatment trial.
Two hundred forty-three Asian patients with primary open-angle or primary angle-closure glaucoma undergoing primary trabeculectomy.
One eye of each patient was randomized to receive either intraoperative 5-FU or normal saline (placebo) during trabeculectomy.
Primary outcome measure was the level of intraocular pressure (IOP). Secondary outcomes were progression of visual field loss, rates of adverse events, and interventions after surgery.
Of the 288 eligible patients, 243 were enrolled and 228 completed 3 years follow-up; 120 patients received 5-FU and 123 received placebo. Trial failure, according to predefined IOP criteria, was lower in the 5-FU group compared with the placebo group, although the difference was only significant with a failure criterion of IOP >17 mmHg (P = 0.0154). There was no significant difference in progression of optic disc and/or visual field loss over 36 months between 5-FU and placebo (relative risk RR, 0.67; 95% confidence interval CI, 0.34-1.31; P = 0.239). Uveitis occurred more often in the 5-FU-treated group (14/115 12% vs 5/120 4%; P = 0.032).
This is the first masked, prospective, randomized trial reporting the effect of adjunctive 5-FU in trabeculectomy surgery in an East Asian population. The trial shows that an increased success rate can be achieved for several years after a single intraoperative treatment with 5-FU. We conclude that 5-FU is relatively safe and can be routinely used in low-risk East Asian patients.
The authors have no proprietary or commercial interest in any materials discussed in this article.
To investigate longitudinal changes in anterior chamber depth (ACD) and axial length (AXL) over 5 years after trabeculectomy surgery in Asian patients with primary glaucoma, and to identify factors ...associated with these changes.
In this prospective cohort study, phakic subjects with primary glaucoma who underwent trabeculectomy had ACD and AXL measured over 5 years. The effect of intraocular pressure (IOP) on ACD and AXL was determined. Subjects were divided into two groups (high or low fluctuation of ACD/AXL) and factors were compared to determine if there were factors associated with greater fluctuation.
122 subjects were analysed. The majority of subjects were male (75.4%) and Chinese (77%). ACD and AXL were shallower/shorter compared with baseline at all postoperative visits, with a mean decrease of 0.11 mm (95% CI 0.07 to 0.15 mm, p<0.01) and 0.16 mm (95%CI 0.11 to 0.20 mm, p<0.01), respectively. Patients with primary open angle glaucoma (POAG) had higher odds of fluctuations in longitudinal measurements of ACD (OR=8.74, p<0.01) and AXL (OR=5.60, p<0.01) compared with patients with primary angle closure glaucoma. For every 1 mm Hg decrease in IOP, ACD and AXL decreased by 0.02 mm (p<0.01) and 0.01 mm (p=0.03), respectively, for POAG patients with emmetropia or mild myopia.
Trabeculectomy resulted in a decrease in both ACD and AXL, and these changes were persistent over a period of 5 years.
To determine the long-term outcome of Asian eyes with an acute attack of primary angle closure (APAC) and to identify risk factors at presentation associated with the development of glaucomatous ...optic nerve damage.
Cross-sectional observational case series.
Ninety individuals who were initially seen with APAC 4 to 10 years previously at 2 Singapore hospitals.
All subjects underwent a complete eye examination, including visual acuity, visual field testing, dilated eye examination, and optic nerve head photography. The optic discs were judged clinically and photographically as to whether there was glaucomatous optic neuropathy present, and visual fields were assessed for corresponding visual field loss. All visual fields and optic nerve photographs underwent a second evaluation by an experienced, but masked, glaucoma specialist, who assessed whether the changes were compatible with glaucoma.
The main outcome measures were blindness (defined as best-corrected visual acuity worse than 6/60 and/or central visual field of less than 20° in the attack eye) and glaucomatous optic neuropathy (GON).
A total of 90 of 170 eligible subjects (65.2%) were examined. All subjects were Asian and were predominantly Chinese (78 subjects 86.7%). There were 61 females (67.8%), and the age of the subjects was 62.0±9.0 years (mean ± standard deviation) at the time of APAC, with a mean duration of 6.3±1.5 years from the time of the APAC episode to the study examination. Sixteen (17.8%) subjects were blind in the attack eye; half of the cases of blindness were caused by glaucoma. Forty-three subjects (47.8%) had GON, with 13 eyes (15.5%) having markedly cupped optic discs (cup-to-disc ratio >0.9). Thirty-eight eyes (58%) had best-corrected vision worse than 6/9, with cataract responsible for close to half the cases of poor vision. There were no identifiable risk factors related to the APAC episode that were significantly associated with the presence of GON.
Several years after being seen with APAC, 17.8% of subjects examined were blind in the attack eye, and almost half had glaucomatous optic nerve damage. Vision was also reduced in a large number of individuals, largely from unoperated cataract. Subjects with APAC would benefit from regular follow-up to monitor for visual field decline and glaucoma development.
To examine the relationship between intraocular pressure (IOP), anthropomorphic, demographic, socioeconomic, systemic, and ocular factors and glaucomatous optic neuropathy (GON) in Chinese people.
...Chinese people (n = 2000), aged 40 to 79 years, were selected from the Singapore electoral register. Of the 1717 considered eligible for examination, 1232 participated, representing a response rate of 71.8%. IOP was estimated with Goldmann applanation tonometry. The drainage angle was assessed with static and dynamic gonioscopy. The optic nerve was examined at high magnification through a dilated pupil with a fundus contact lens or a +78-D lens. Static automated visual field testing was performed on subjects with suspected glaucoma. GON was diagnosed on the basis of structural and functional abnormalities of the optic nerve.
The main independent determinants of higher IOP were higher systolic blood pressure (P < 0.001), quadrants of any peripheral anterior synechiae (PAS, P = 0.02) and width of the drainage angle (P = 0.049). A 100- micro m increase in corneal thickness was associated with an increase in mean IOP of 1.5 to 1.8 mm Hg (P < 0.001). Odds of GON increased 1.2 times per 1-mm Hg increase in screening IOP. A clear association between corneal thickness and GON was not identified.
Clinical IOP estimates are related to systolic blood pressure and corneal thickness. Variation in IOP with angle width may suggest that trabecular compaction significantly contributes to causes of the increase in IOP, independent of angle-closure. GON is an IOP-related phenomenon among Chinese Singaporeans.
