Alexander C Day

The prevalence of primary angle closure glaucoma in European derived populations: a systematic review

Aim To estimate the prevalence of primary angle closure glaucoma (PACG) in European derived populations. Method Systematic review and modelling of PACG prevalence data from population studies. PACG was defined according to the ISGEO definition requiring structural and/or functional evidence of glaucomatous optic neuropathy. Prevalence estimates were applied to the 2010 United Nations projected population figures to estimate case numbers. Results The prevalence of PACG in those 40 years or more is 0.4% (95% CI 0.3% to 0.5%). Age-specific prevalence values are 0.02% (CI 0.00 to 0.08) for those 40–49 years, 0.60% (0.27 to 1.00) for those 50–59 years, 0.20% (0.06 to 0.42) for those 60–69 years and 0.94% (0.63 to 1.35) for those 70 years and older. Three-quarters of all cases occur in female subjects (3.25 female to 1 male; CI 1.76 to 5.94). Conclusion This analysis provides a current evidence-based estimate of PACG prevalence in European derived populations and suggests there are 130 000 people in the UK, 1.60 million people in Europe and 581 000 people in the USA with PACG today. Accounting for ageing population structures, cases are predicted to increase by 19% in the UK, 9% in Europe and 18% in the USA within the next decade. PACG is more common than previously thought, and all primary glaucoma cases should be considered to be PACG until the anterior chamber angle is shown to be open on gonioscopy.

The Royal College of Ophthalmologists’ National Ophthalmology Database study of cataract surgery: report 1, visual outcomes and complications

AimsTo describe the outcomes of cataract surgery in the United Kingdom.MethodsAnonymised data on 180 114 eyes from 127 685 patients undergoing cataract surgery between August 2006 and November 2010 were collected prospectively from 28 sites. Outcome measures included intraoperative and postoperative complication rates, and preoperative and postoperative visual acuities.ResultsMedian age at first eye surgery was 77.1 years, 36.9% cases had ocular co-pathology and 41.0% patients underwent cataract surgery on both eyes. Preoperative visual acuity was 0.30 logMAR or better in 32.0% first eyes and 47.7% second eyes. Postoperative best-measured visual acuity was 0.00 and 0.30 logMAR or better in 50.8 and 94.6% eyes without ocular co-pathology, and 32.5 and 79.9% in eyes with co-pathology. For eyes without co-pathology, postoperative uncorrected distance visual acuity was 0.00 and 0.30 logMAR or better in 27.3 and 80.9% eyes. Posterior capsule rupture or vitreous loss or both occurred in 1.95% cases, and was associated with a 42 times higher risk of retinal detachment surgery within 3 months and an eight times higher risk of endophthalmitis.ConclusionThese results provide updated data for the benchmarking of cataract surgery. Visual outcomes, and the rate of posterior capsule rupture or vitreous loss or both appear stable over the past decade.

Outcomes of phacoemulsification and intraocular lens implantation in microphthalmos and nanophthalmos

Purpose To evaluate the outcomes of phacoemulsification and intraocular lens (IOL) implantation in microphthalmos and nanophthalmos. Setting Moorfields Eye Hospital, London, United Kingdom. Design Retrospective case series. Methods Eyes with an axial length (AL) less than 21.0 mm had elective phacoemulsification and IOL implantation. Results One hundred three eyes (63 patients) were enrolled. The median AL was 20.65 mm (interquartile range [IQR], 20.26 to 20.86) and the median follow‐up, 6.3 months. Complications occurred in 16 cases (15.5%). Zonular dehiscence, severe uveitis, and aqueous misdirection accounted for the majority of complications. Complication rates were 6 (7.3%) of 82 cases with an AL from 20.0 to 21.00 mm and 10 (47.6%) of 21 cases with an AL less than 20.0 mm (P=.0001). Only AL (odds ratio [OR], 0.52 per mm; P≤.0005) and abnormal intraocular pressure (IOP) of 22 mm Hg or more or on topical IOP control (OR, 10.1; P=.001) were significant independent risk factors for complications. For the cohort after adjusting for abnormal IOP, an AL less than 20.5 mm was associated with a 4 times higher odds of any complication (P=.028), an AL less than 20.0 mm was associated with a 15 times higher odds of any complication (P≤.0005), and an AL less than 19.00 mm was associated with a 21 times higher odds of any complication (P≤.0005). Conclusions Phacoemulsification and IOL implantation in microphthalmos/nanophthalmos was challenging but appears safer than previously reported. A shorter AL and abnormal IOP were significant risk factors for complications. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Spectral domain optical coherence tomography imaging of the aqueous outflow structures in normal participants of the EPIC-Norfolk Eye Study.

Purpose To measure the dimensions of aqueous outflow structures and to investigate associations with intraocular pressure (IOP) and ocular biometry parameters in an older British population. Method Fifty-two participants from the European Prospective Investigation of Cancer-Norfolk eye study underwent imaging using the Heidelberg Spectralis optical coherence tomographer with an anterior segment module. Pseudophakic participants and those known or suspected to have glaucoma were excluded, leaving 46 participants for analysis. Schwalbes line (SL), scleral spur (SS), Schlemms canal (SC) diameter and the trabecular meshwork cross-sectional area (TM cross-sectional area (CSA)) were identified and traced using ImageJ software. IOP was measured using the Ocular Response Analyser. Ocular biometry was measured by partial coherence interferometry. Results The mean (SD) subject age was 65.7 years (5.6). The SL and SS were identifiable in all nasal and temporal scans. The mean SL–SS distance was 800 μm (104) nasally and 808 μm (102) temporally. Repeatability of SS–SL, SS–SC, SC and TM CSA was good to excellent, and reproducibility fair to good. Nasal SL–SS distance was inversely associated with anterior chamber depth (ACD) (p=0.007, −116 μm per mm ACD, R2=0.18). Multiple linear regression showed nasal TM CSA was significantly associated with age and IOP (age: p=0.025, 0.007 mm2 per decade of age; IOP: p=0.029, −0.0012 mm2 per mm Hg, R2=0.23). Conclusions Aqueous outflow structures can be measured by optical coherence tomography, and their dimensions vary significantly with ocular biometric characteristics and IOP. Further investigation is required to determine associations between outflow structure sizes in different populations and pathologies, including ocular hypertension and glaucoma.

Genotype-phenotype analysis of SNPs associated with primary angle closure glaucoma (rs1015213, rs3753841 and rs11024102) and ocular biometry in the EPIC-Norfolk Eye Study.

Aims To investigate if the single nucleotide polymorphisms rs3753841, rs1015213 and rs11024102, recently implicated in the development of acute primary angle closure or primary angle closure glaucoma, are associated with ocular biometric characteristics of British adults in the European Prospective Investigation of Cancer-Norfolk eye study. Methods Genotyping data on rs1015213 (between PCMTD1 and ST18), rs11024102 (at PLEKHA7) and rs3753841 (at COL11A1) were available on 3268 participants. Direct genotypic data was available for rs1015213 and rs3753841. Data was imputed for rs11024102. Ocular biometric data was available on 1137 participants who attended the third European Prospective Investigation of Cancer health examination and 988 (87%) of these participants had no previous cataract surgery either eye. Axial length (AL), anterior chamber depth (ACD) and corneal keratometry were measured by using the Zeiss IOLMaster. Results Presence of at least one A allele (AG or AA genotype) for rs1015213 was associated with a shallower ACD (−0.07 mm, 95% CI −0.01 to −0.14 mm, p=0.028) after adjusting for age and sex (both p≤0.001). There was no association with AL or corneal keratometry for rs1015213 genotypes. AL, ACD and keratometry were not associated with rs3753841 or rs11024102 genotypes including after adjusting for age and sex. Conclusions This study suggests that primary angle closure glaucoma susceptibility at the PCMTD1-ST18 locus may be partly explained by an association between rs1015213 and ACD in European populations. This effect is equivalent to almost 20% of the SD of the mean ACD of phakic individuals in this cohort. We were not able to identify any association between rs3753841 or rs11024102 and ocular biometry.

Nonpenetrating femtosecond laser intrastromal astigmatic keratotomy in eyes having cataract surgery

Purpose To describe the effect of femtosecond laser intrastromal astigmatic keratotomy (AK) performed during cataract surgery. Setting Moorfields Eye Hospital, London, United Kingdom. Design Prospective case series. Methods This study comprised patients having laser cataract surgery with concurrent astigmatism management by intrastromal AK. All eyes had greater than 0.7 corneal diopter (D) cylinder. An intrastromal AK nomogram with 8.0 mm diameter paired symmetric limbal centered arcs was used. Corneal keratometry was measured preoperatively and 1 month postoperatively using a KR8100PA topographer–autorefractor. Astigmatic analyses were performed using the Alpins method considering 3 vectors—target induced astigmatism (TIA), surgically induced astigmatism (SIA) and difference vector (DV)—and calculation of coupling measures. Results In all, 196 eyes of 133 patients were analyzed. The mean TIA (equivalent to preoperative corneal cylinder) was 1.21 D ± 0.42 (SD) (range 0.75 to 2.64 D) and the mean SIA was 0.74 DC ± 0.40 (range 0.00 to 2.86). The mean difference vector was 0.74 ± 0.38 D (range 0.00 to 2.25 D). The mean correction index was 0.63 ± 0.32 (range 0.00 to 1.93), indicating that the mean astigmatism correction was 63%. Fourteen eyes (7.1%) and 7 eyes (3.6%) had an astigmatism correction of greater than 100% and greater than 120%, respectively. Overall 0%, 48.5%, and 51.5% of eyes had 0.50 D or less, 1.0 D or less, or greater than 1.0 D, respectively, preoperatively compared with 32.1%, 85.7%, and 14.3%, postoperatively. There were no cases of corneal endothelial perforation or inadvertent placement within the visual axis. Conclusions The intrastromal AKs were easily programmed as an integral part of laser‐assisted cataract surgery without additional cost, significantly reduced corneal cylinder, and appeared to be safe through 1 month of follow‐up. Financial Disclosure Dr. Day was supported by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology. Dr. Stevens has been a consultant to Optimedica Inc., now part of Abbott Medical Optics.

Accuracy of intraocular lens power calculations in eyes with axial length <22.00 mm.

Background:  To assess the accuracy of Haigis, Holladay 1, Hoffer Q and SRK/T formulae in eyes with axial length of <22.00 mm.

Central Corneal Thickness and Glaucoma in East Asian People

PURPOSE To examine the association between central corneal thickness (CCT) and glaucoma. METHODS This was a nested case-control study using 1090 subjects from an eye disease population survey in Singapore and 243 participants from a hospital glaucoma surgery clinical trial in Singapore. RESULTS Mean CCT in 938 community subjects was 539 μm ± 32 μm, and in 12 community subjects with primary open angle glaucoma (POAG) the mean CCT was 545 μm ± 38 μm. In the hospital cohort, mean CCT was 552 μm ± 38 μm in 138 patients with POAG and 551 μm ± 33 μm in 105 patients with primary angle closure glaucoma (PACG). No individuals had undergone previous intraocular surgery or had other significant ocular pathology. Regression models showed POAG diagnosis was not associated with CCT (P = 0.42) or age (P = 0.062) in community subjects but was associated with IOP (P = 0.005). Similar analyses for hospital cases showed CCT to be significantly higher in both POAG and PACG (both P = 0.001), but this became nonsignificant after controlling for IOP and age (P = 0.26, POAG; P = 0.08, PACG). Both age (P = 0.043) and IOP (P = 0.001) were highly associated with hospital POAG; only IOP (P = 0.001) was associated with hospital PACG. Further regression analyses for community subjects showed diabetic status and pseudophakia had no significant effect on CCT (P = 0.33 and P = 0.11, respectively). CONCLUSIONS The authors found no evidence to support the previous observation that thinner corneas may be independently associated with POAG or PACG. Age and IOP are significantly associated with CCT, and this should be taken into account by future studies investigating CCT as an independent risk factor for glaucoma diagnosis.

Randomised trial of sequential pretreatment for Nd:YAG laser iridotomy in dark irides

Aims To compare iridotomy outcomes in dark irides by 1064 nm pulsed Nd:YAG laser with and without 532 nm continuous-wave Nd:YAG (frequency-doubled) green laser pretreatment. Methods 30 patients with occludable anterior chamber angles underwent bilateral standard pulsed 1064 nm Nd:YAG laser iridotomy with one eye randomly assigned to sequential pretreatment with 532 nm continuous-wave Nd:YAG laser. Outcome measures were iridotomy patency and complications including haemorrhage and elevated intraocular pressure (IOP). Results Median pulsed YAG power in the standard treatment group was 37.5 mJ (IQR 25–77) and 22.5 mJ (IQR 14–32) in the sequential treatment group (p=0.0079). Iris haemorrhage occurred in 43% of the standard treatment group and 13% of the sequential treatment group (p=0.0126). All iridotomies were patent at the end of the procedure in the sequential treatment group, while 2/30 in the standard treatment group were abandoned due to significant haemorrhage. Mean IOP at 1 h was significantly lower than pre-laser values in both groups (with magnitude of reduction significantly more in the sequential treatment group). There was no significant change in IOP at 1 week. All iridotomies were patent at last follow-up of median 38.5 months (IQR 32.0–42.3). Conclusions This study provides evidence that iridotomy with pretreatment using a continuous-wave Nd:YAG laser is safer and more effective than pulsed Nd:YAG-only laser iridotomy for dark irides and should be considered as the preferred technique.

Increases in rates of both laser peripheral iridotomy and phacoemulsification have accompanied a fall in acute angle closure rates in the UK.

Acute angle closure (AAC) is fortunately uncommon with reported incidences of —three to four cases per year per 100 000 population in European populations.1 2 Previous data from the UK Department of Healths Hospital Episode Statistics (HES) internet site up to 2004 had suggested that primary angle closure glaucoma (PACG) cases were …