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Background: We evaluated whether the best‐fit intraocular lens (IOL) power formula for the first operated eye (BF1) was also the most accurate formula for the second eye. Methods: This was a retrospective study of 152 patients who underwent uncomplicated delayed bilateral cataract surgery with a minimum delay of 3 weeks using only one 1‐piece IOL (HOYA, Vivinex) at the Medical University of Vienna, Austria. Seven different formulae (Barrett Universal II, Castrop, Haigis, Hoffer Q, Holladay 1, Kane, and SRK/T) were investigated to test the formula selection approach with regard to the calculated mean and median absolute prediction errors (MAE/MedAE). Results: The mean intraindividual difference in axial length was 0.2 mm (±0.3 mm). BF1 coincided with the best‐fit formula for the second eye (BF2) in 56% of patients (p < 0.05). Using BF1 for the second eye led to a lower MedAE (0.22 dioptre, D) than using a formula at random (0.33 D) and was less accurate than using the best‐fit formula for each eye separately (0.1 D). The MedAEs of all formulae were generally low, ranging from 0.28 to 0.35 D. Conclusion: Using BF1 for the second eye led to a lower MedAE than the random selection of a formula. Therefore, BF1 can be used for the second eye if the surgeon is unsure of the choice of formula. [ABSTRACT FROM AUTHOR]

Background: To report long‐term biometric and refractive outcomes in a group of Danish children after surgery for childhood cataract. Methods: Children between 7 and 18 years who had undergone uni‐ or bilateral cataract surgery at the Department of Ophthalmology, Rigshospitalet, Denmark, were examined in this cross‐sectional study. Swept source optical coherence tomography (OCT) based optical biometry (IOLmaster 700) and anterior tomography (Pentacam) was performed. Healthy fellow eyes from those with unilateral cataract were used as controls. Results: We included 56 children in the study with a median age at surgery of 43.8 months (1.6–137.6). The amount of higher order aberrations was significantly increased in operated eyes (median root mean square 0.461 μm [range 0.264–1.484]) compared with non‐operated eyes (median root mean square 0.337 μm [range 0.162–0.498], p < 0.001). Younger age at surgery was positively associated with more higher order aberrations at follow‐up (p < 0.001), but we found no significant associations between the amount of higher order aberrations and visual acuity or contrast vision. Longer axial length was associated to glaucoma while shorter axial length was associated to strabismus (p < 0.001). Conclusions: Eyes operated for childhood cataract have higher order aberrations compared with non‐operated eyes. Higher order aberrations are complex refractive errors that cannot be corrected by normal lenses and may contribute to poor visual outcomes for the children. We found an association between young age at surgery and higher order aberrations. [ABSTRACT FROM AUTHOR]

Uncorrected refractive astigmatism degrades visual acuity. Spherical intraocular lenses (IOLs) leave astigmatic errors resident in the cornea manifest in refractive astigmatism. Toric IOLs, correcting for this corneal astigmatism, contribute to spectacle‐free vision in the pseudophakic eye. This review provides information to assist surgeons in a rational choice of eyes suitable for toric IOL implantation, methods of IOL cylinder power calculation, surgical techniques for toric IOLs and management of complications. With appropriate application of this information, correction of visually detrimental astigmatism can be achieved routinely. [ABSTRACT FROM AUTHOR]

Importance Cataract and primary open‐angle glaucoma (POAG) commonly co‐exist, and cataract surgery is thought to reduce intraocular pressure (IOP), the major modifiable risk factor of POAG. Background: Previous studies exploring the effect of cataract surgery on IOP are limited by retrospective design, lack of a control group, medication use and washout and loss to follow up. Design Prospective, multicentre, matched case‐control Australian study. Participants: 171 eyes of 108 POAG patients who underwent cataract surgery, matched to 171 control eyes. Methods: Serial longitudinal IOP measurements were compared before and after cataract surgery, and relative to the controls. A mixed‐effect model was used for the longitudinal data. Main Outcome Measures: Change in IOP. Results: The mean follow‐up time was 4.8 (1.4) years. Cataract surgery reduced mean IOP by 2.22 mmHg (95% confidence interval: 1.93‐2.52 mmHg, P <.001) with 59 eyes (34%) achieving at least 3 mmHg reduction. Compared to matched controls, the mean reduction in IOP was 1.75 mmHg (95% confidence interval 1.15‐2.33 mmHg; P <.001). Higher preoperative IOP and being on fewer topical glaucoma medications preoperatively were strongly predictive of a larger IOP reduction in a multivariable model. Anterior chamber depth was not associated with IOP reduction. Eyes with preoperative IOP ≥24 mmHg had a mean IOP reduction of 4.03 mmHg with 81% experiencing at least 3 mmHg reduction. Sub‐analysis of medication naïve and pseudoexfoliation patients showed similar results. Conclusions and Relevance: Cataract surgery has a confirmed effect in reducing IOP in a "real world" setting of early glaucoma patients. [ABSTRACT FROM AUTHOR]

Background To assess the corneal diameter and its associations in children. Design Cross-sectional school-based study. Participants Six thousand twenty-six children aged 4-18 years were included in the Shandong Children Eye Study. Methods Horizontal corneal diameter was measured by laser interferometry-based ocular biometry. Main Outcome Measures Horizontal corneal diameter. Results Corneal diameter measurements were available for 5970 (99.1%) children. In multivariate analysis, larger horizontal corneal diameter (mean: 12.02 ± 0.38 mm; range: 10.1-15.0 mm) was associated with longer corneal curvature radius longer axial length, male gender, younger maternal age, rural region of habitation and lower intraocular pressure measurements. Higher prevalence of abnormally large corneas (macrocorneas; horizontal diameter ≥ 12.76 mm; mean value +2 × standard deviations; mean: 2.6%; 95% CI: 2.2, 3.0) was associated with longer corneal curvature radius, longer axial length, younger maternal age and male gender. Higher prevalence of abnormally small corneas (horizontal diameter ≤ 11.24mm; mean value −2 × standard deviations; mean: 2.4%; 95% CI: 2.0, 2.8) was correlated with shorter corneal curvature radius, shorter axial length and urban region of habitation. Neither abnormally large nor small corneas were correlated with time spent indoors/outdoors. Conclusions In 4 to 18-year-old children, larger corneal diameter was associated most strongly with flatter corneal curvature, followed by longer axial length and male gender. Corneal diameter was independent of age beyond an age of 4 years. Abnormally large and abnormally small corneas may be defined as being ≥12.76 and ≤11.24 mm in diameter, respectively. Corneal diameter was not correlated with time spent indoors/outdoors. [ABSTRACT FROM AUTHOR]

Background This study aimed to evaluate differences in iris gene expression profiles between primary angle closure glaucoma (PACG) and primary open angle glaucoma (POAG) and their interaction with biometric characteristics. Design Prospective study. Participants Thirty-five subjects with PACG and thirty-three subjects with POAG who required trabeculectomy were enrolled at the Singapore National Eye Centre, Singapore. Methods Iris specimens, obtained by iridectomy, were analysed by real-time polymerase chain reaction for expression of type I collagen, vascular endothelial growth factor (VEGF)-A, -B and -C, as well as VEGF receptors (VEGFRs) 1 and 2. Anterior segment optical coherence tomography (ASOCT) imaging for biometric parameters, including anterior chamber depth (ACD), anterior chamber volume (ACV) and lens vault (LV), was also performed pre-operatively. Main Outcome Measures Relative mRNA levels between PACG and POAG irises, biometric measurements, discriminant analyses using genes and biometric parameters. Results COL1A1, VEGFB, VEGFC and VEGFR2 mRNA expression was higher in PACG compared to POAG irises. LV, ACD and ACV were significantly different between the two subgroups. Discriminant analyses based on gene expression, biometric parameters or a combination of both gene expression and biometrics (LV and ACV), correctly classified 94.1%, 85.3% and 94.1% of the original PACG and POAG cases, respectively. The discriminant function combining genes and biometrics demonstrated the highest accuracy in cross-validated classification of the two glaucoma subtypes. Conclusions Distinct iris gene expression supports the pathophysiological differences that exist between PACG and POAG. Biometric parameters can combine with iris gene expression to more accurately define PACG from POAG. [ABSTRACT FROM AUTHOR]

Background To evaluate the biometric factors associated with the accuracy of intraocular lens power predictions for cataract surgery in primary angle-closure (PAC) or primary angle-closure glaucoma (PACG) eyes. Design Cross-sectional study Participants This study included 103 PAC or PACG patients who had undergone cataract surgery. Methods All participants underwent anterior-segment optical coherence tomography preoperatively. Two novel biometric factors - the relative lens vault (the ratio of lens vault to anterior vault) and the anterior vault (the sum of lens vault and anterior chamber depth) - were measured using customized software. The powers of the implanted intraocular lens and the actual postoperative refractive errors were compared. The mean refractive error and the median absolute error were calculated and compared using repeated measures ANOVA and Wilcoxon matched-pairs signed-rank test. The biometric factors associated with the postoperative refractive error were investigated by multivariate regression analysis. Main Outcome Measures Preoperative anterior-segment biometric factors, difference between predicted and actual postoperative refraction. Results The Haigis, Hoffer Q and SRK/T formulas all showed a slight tendency toward resultant hyperopia, respectively ( P < 0.001, P = 0.05, P = 0.003). The Hoffer Q formula had the least prediction error ( P < 0.001). In the multivariate regression analysis, the relative lens vault was the only independent factor predicting postoperative refractive error ( β = 0.392, P = 0.011). Conclusion Intraocular lens power predictions for cataract surgery in PAC or PACG patients can be inaccurate. Such results might be associated with anterior-segment biometric factors. Preoperative relative lens vault appears to be a significant factor predicting refractive outcome after cataract surgery in patients with PAC or PACG. [ABSTRACT FROM AUTHOR]

Background: The aim is to investigate ethnic variation, in presentation and biometric parameters, within the population undergoing cataract surgery in Auckland. Design: The design is a retrospective study. Participants: Four thousand nine hundred thirty-one eyes of 3524 consecutive patients undergoing cataract surgery in Auckland Public Hospital over 18 months were included in the study. Methods: Analysis of preoperative medical records was performed. Main Outcome Measures: Age, gender, self-reported ethnicity, keratometry, anterior chamber depth, axial length and intraocular lens (IOL) power data were collected. Results: Māori (4.7%) were under-represented compared with the proportion of Māori attending the eye clinic (5.5%) and in the major patient catchment area (8.2%). People of Māori, Pacific and Indian ethnicities presented at a significantly younger age (66.4, 65.9 and 67.9 years, respectively) than those of Caucasian and Asian ethnicities (76.4 and 71.3 years, respectively, P<0.001). Advanced cataract was more likely in Pacific peoples and Māori than Caucasians. The mean axial length was longest in Asian eyes (23.83 ± 1.52 mm). The mean anterior chamber depth in the eyes of Pacific peoples (3.20 ± 0.39mm) was significantly greater than that of Caucasians (3.09 ± 0.42mm, P = 0.001) and Asians (3.05 ± 0.49mm, P<0.001). The mean IOL power in Asian eyes was 19.45D. This was significantly lower than the IOL power required by Caucasian (20.72D, P<0.001) and Pacific ethnicities (20.61D, P = 0.001). With-the-rule astigmatism was highly prevalent in Māori and Pacific peoples, whereas in all other ethnicities, against-the-rule astigmatism was more common. Conclusions: This study identified significant ethnic variation in presentation for cataract surgery and ocular biometric parameters. These data may help identify potential biometric refinements and those at risk of developing ocular morbidities known to be associated with these parameters. [ABSTRACT FROM AUTHOR]

Background To evaluate the accuracy of predicted refraction using multifocal intraocular lenses ( IOLs) with power calculation based on two biometric devices and multiple IOL power calculation formulas. Design A retrospective study conducted in a private practice ophthalmology clinic. Participants Seventy-three eyes of 48 patients were evaluated. Methods Consecutive cases of eyes that had undergone successful cataract surgery with an implantation of a multifocal IOL ( SN6 AD1, Alcon Laboratories, Inc., Fort Worth, TX, USA) by a single surgeon were enrolled. Patients were meticulously screened for suitability for a multifocal IOL implantation according to our clinic guidelines. Two biometric measurement devices ( IOLMaster-500 [ Carl Zeiss Meditec AG, Jena, Germany] and Lenstar- LS900 [ Haag- Streit AG, Koeniz, Switzerland]) were used under strict validation criteria to evaluate the predicted refraction errors for the Holladay 1, SRK/ T, Hoffer Q, Haigis, Holladay 2, Barrett Universal II and Olsen formulas. Main Outcome Measures Predicted refractive sphere equivalent ( RSE) errors. Results The measurements obtained from the two biometric devices were highly correlated. The standard deviation of the error in predicted RSE and the median absolute error were similar for the IOLMaster and the Lenstar devices using all formulas, ranging from 0.27 dioptres ( D) to 0.31 D and from 0.15 D to 0.21 D, respectively. A high percentage of eyes had an error in predicted RSE within ±0.5 D from target refraction, ranging from 86.3% to 93.2%. Conclusions High accuracy can be achieved in multifocal IOL power calculations by appropriate patient selection, precise biometry and appropriate IOL calculation formulas. [ABSTRACT FROM AUTHOR]

Background To compare anterior segment biometric parameters between Caucasians and Chinese before and after laser peripheral iridotomy. Design Prospective clinical cohort study. Participants Caucasian and Chinese primary angle-closure suspects. Methods Anterior segment optical coherence tomography images captured before and after laser peripheral iridotomy were analysed to measure anterior segment biometric parameters. Paired Student's t-tests were used for within-ethnic group comparisons. Univariate and linear mixed-effect regression models were used for between-ethnic group comparisons. Main Outcome Measures Angle opening distance, angle recess area, iris thickness, iris curvature, anterior chamber area, anterior chamber volume and anterior chamber width. Results Caucasians had significantly greater preoperative angle recess area, anterior chamber width, and iris curvature and lower preoperative iris thickness compared to Chinese ( P < 0.05). Significant postoperative increases in angle opening distance, angle recess area, anterior chamber area, anterior chamber volume, and anterior chamber width along with significant postoperative decrease in iris curvature were observed within both ethnic groups ( P < 0.05). However, the amount of laser peripheral iridotomy-induced changes in angle opening distance, angle recess area, anterior chamber area, anterior chamber volume, anterior chamber width, and iris curvature did not differ between the two ethnic groups ( P < 0.05). Conclusion Both Caucasian and Chinese demonstrated opening of anterior chamber angle width, expansion of anterior chamber dimensions, and flattening of iris convexity after laser peripheral iridotomy. Although certain aspects of anterior segment anatomy differed between Caucasians and Chinese preoperatively, they did not translate into significant ethnic differences in the amount of laser peripheral iridotomy-induced changes in the anterior segment biometric parameters. [ABSTRACT FROM AUTHOR]

A bstract Background: To establish whether simulated keratometry values obtained by corneal mapping (videokeratography) would provide a superior refractive outcome to those obtained by Zeiss IOLMaster (partial coherence interferometry) in routine cataract surgery. Design: Prospective, non-randomized, single-surgeon study set at the The Royal United Hospital, Bath, UK, District General Hospital. Participants: Thirty-three patients undergoing routine cataract surgery in the absence of significant ocular comorbidity. Methods: Conventional biometry was recorded using the Zeiss IOLMaster. Postoperative refraction was calculated using the SRK/T formula and the most appropriate power of lens implanted. Preoperative keratometry values were also obtained using Humphrey Instruments Atlas Version A6 corneal mapping. Main Outcome Measures: Achieved refraction was compared with predicted refraction for the two methods of keratometry after the A-constants were optimized to obtain a mean arithmetic error of zero dioptres for each device. Results: The mean absolute prediction error was 0.39 dioptres (standard deviation 0.29) for IOLMaster and 0.48 dioptres (standard deviation 0.31) for corneal mapping ( P = 0.0015). Keratometry readings between the devices were highly correlated by Spearman correlation (0.97). The Bland-Altman plot demonstrated close agreement between keratometers, with a bias of 0.0079 dioptres and 95% limits of agreement of −0.48-0.49 dioptres. Conclusions: The IOLMaster was superior to Humphrey Atlas A6 corneal mapping in the prediction of postoperative refraction. This difference could not have been predicted from the keratometry readings alone. When comparing biometry devices, close agreement between readings should not be considered a substitute for actual postoperative refraction data. [ABSTRACT FROM AUTHOR]

A bstract Background: To assess the accuracy of Haigis, Holladay 1, Hoffer Q and SRK/T formulae in eyes with axial length of <22.00 mm. Design: Retrospective comparative analysis. Participants: 163 eyes of 97 patients undergoing phacoemulsification and intraocular lens (IOL) implantation. Methods: Ocular biometry was performed using IOLMaster laser interferometry. Predicted refractive outcomes before and after lens constant adjustment were compared to actual refractive outcomes. Main Outcome Measures: Mean prediction (ME) and mean absolute errors (MAE) with standard deviations (±SD). Results: Mean preoperative spherical equivalent was +5.44D ± 1.97D. Mean axial length was 21.20 mm ± 0.60 mm. Using standard IOL constants the MAE for Hoffer Q (0.62D, ±0.52D) and Holladay 1 (0.66D ± 0.52D) were significantly lower than SRK/T (MAE 0.91D ± 0.64D; P = <0.0005 and P = 0.001 respectively), but not Haigis (MAE 0.82D ± 0.83D, P = 0.071 and 0.22 respectively). MAEs for all formulae were significantly reduced by IOL constant adjustment (all P = <0.001). Following this there was no statistically significant difference in MAEs between formulae (range 0.50-0.57D, P = 0.57). Increasing MAE was significantly associated with reducing axial length and increasing IOL power for all formulae. For bilateral cases, prediction errors between eyes were significantly correlated across all formulae (all P = <0.0001) and explained 32-42% of the variance in prediction error between eyes. Conclusions: Prediction of postoperative refraction in patients with short axial lengths is challenging and at the limit of current, popular IOL formulae. There is now a clear need for prospective studies to assess latest generation IOL formulae such as Holladay 2 or Olsen in small eyes. [ABSTRACT FROM AUTHOR]

A bstract Background: To compare the anterior segment biometric parameters amongst adult American Caucasians, American Chinese and mainland Chinese, in order to determine parameters that may contribute to increased risk for angle closure in Chinese. Design: Cross-sectional clinic-based study Participants: Four gender- and age-matched cohorts included Caucasians, American Chinese, Southern and Northern mainland Chinese. Methods: Anterior segment optical coherence tomography was utilized to image the anterior chamber. Customized software was used to calculate the anterior segment parameters. Main Outcome Measures: Anterior chamber depth, anterior chamber width, lens vault and corneal arc depth. Results: Data from 121, 124, 121 and 120 subjects were available for American Caucasian, American Chinese, and Southern and Northern Mainland Chinese subjects, respectively. Caucasians had significantly greater anterior chamber depth, anterior chamber width and corneal arc depth than all Chinese groups even after adjustment for refractive status and axial length. In multiple regression analysis, predictors of greater lens vault were female gender, older age and more hyperopic/less myopic status for both racial groups. It was found only in Chinese that female and older subjects tended to have smaller anterior chamber depth, anterior chamber width and corneal arc depth. Conclusion: The shallower anterior chamber in Chinese than Caucasians is likely attributable to the shorter corneal arc depth in the former group. Moreover, the smaller anterior chamber width contributes to more crowded anterior chambers in Chinese than in Caucasians. The more anteriorly located lens under a less vaulted cornea in Chinese females compared with Chinese males may account for the higher risk of angle closure in this subpopulation. [ABSTRACT FROM AUTHOR]

bstract [ABSTRACT FROM AUTHOR]

Purpose: To report the value of dual biometry in the detection of biometry errors. Methods: Study 1: retrospective study of 224 consecutive cataract operations. The intraocular lens power calculation was based on immersion biometry. Study 2: immersion biometry was compared with optical coherence biometry (OCB) in terms of axial length, anterior chamber depth, keratometry readings and the recommended lens power to achieve emmetropia. Study 3: prospective study of 61 consecutive cataract operations. Both immersion and OCB were performed, but lens power calculation was based on the latter. Results: Study 1: 115 (86%), 101 (75.4%), 90 (67.2%) and 50 (37.3%) of postoperative spherical equivalents were within ±1.5 dioptres (D), ±1.25 D, ±1 D and ±0.5 D of the target, respectively. Study 2: excellent agreement between axial length readings, anterior chamber depth readings and keratometry readings by immersion biometry and OCB was observed (reflected in a mean bias of −0.065 mm, −0.048 mm and +0.1803 D, respectively, in association with OCB). Agreement between the lens power recommended by each technique to achieve emmetropia was poor (mean bias of +1.16 D in association with OCB), but improved following appropriate modification of lens constants in the Accutome A-scan software (mean bias with OCB = −0.4 D). Study 3: 37 (92.5%) and 23 (57.5%) of operated eyes achieved a postoperative refraction within ±1 D and ±0.5 D of target, respectively. Conclusion: Systematic errors in biometry can exist, in the presence of acceptable postoperative refractive results. Dual biometry allows each biometric parameter to be scrutinized in isolation, and identify sources of error that may otherwise go undetected. [ABSTRACT FROM AUTHOR]

Background: The IOLMaster determines axial length using partial coherence interferometry. This study was designed to compare the refractive outcomes of patients who had been measured preoperatively by both immersion ultrasound and IOLMaster biometry. Methods: Patients were recruited from those who had undergone cataract surgery during the preceding 12 months by one surgeon at The Queen Elizabeth Hospital (55 eyes from 55 patients). Each patient underwent measurement of axial length by immersion ultrasound and the IOLMaster. Target refraction was determined using an SRK-T formula and the amount that this differed postoperative refraction was calculated for immersion ultrasound and the IOLMaster. These results were then compared. Results: Eyes measured longer by the IOLMaster method compared with immersion ultrasound (23.37 ± 0.87 vs. 23.25 ± 0.90 mm, t = 4.83; P < 0.0001). However anterior chamber depth was the similar. Postoperatively, final refractive outcome was 0.01 ± 0.63 dioptres (D) more hypermetropic than the target refraction when using the IOLMaster compared with 0.25 ± 0.73 D more myopic when using immersion ultrasound ( t = 3.83; P < 0.0001). Seventy-five per cent of patients were within 0.5 D of target refraction and 93% were within 1.0 D when the IOLMaster was used, compared with 49% and 85% within 0.5 and 1.0 D respectively when using immersion ultrasound (χ2 = 8.34; P = 0.04). Conclusions: Biometry performed using the IOLMaster produces a more predictable refractive outcome than immersion ultrasound, with patients' spherical equivalent more likely to be closer to their target refraction. [ABSTRACT FROM AUTHOR]

Purpose: To study the association between adult stature and ocular biometric parameters and refraction. Methods: In a population-based cross-sectional ophthalmic survey of 2418 adults (≥40 years old) living in the rural villages in central Myanmar, height and weight were measured using a standardized protocol, and body mass index was calculated. Non-cycloplegic refraction and corneal curvature were determined by an autorefractor. Ultrasound pachymetry was performed and ocular biometry, including axial length, anterior chamber depth, lens thickness and vitreous chamber length were measured using A-mode ocular ultrasonography. Results: Height and weight were significantly correlated with age, gender and all the ocular biometric parameters, except lens thickness. After adjusting for age and gender, taller and heavier persons had eyes with longer axial length, deeper anterior and vitreous chambers, and flatter and thicker corneas than shorter persons. Height was not significantly correlated with refraction, and heavier persons tended to be less myopic ( P < 0.001). Multivariate linear regression models revealed consistent results with the findings for association between height, weight and ocular biometry and refractive error. Conclusions: Adult stature is independently associated with vitreous chamber length and corneal radius in this Burmese population. Heavier persons were slightly hyperopic. [ABSTRACT FROM AUTHOR]

Purpose: To determine the survival of patients with sighted eyes who had Molteno implants inserted for neovascular glaucoma. Methods: Patients who had Molteno implants inserted for neovascular glaucoma between October 1977 and March 2001 at Dunedin Hospital, New Zealand, were reviewed. Relative survival analysis was then used to compare survival in this group to survival of the New Zealand population of the same age. Results: A total of 114 patients had 131 Molteno implants inserted for neovascular glaucoma. Neovascular glaucoma was secondary to central retinal vein occlusion in 66 eyes (50%) and diabetes in 42 eyes (32%), and patients lost 52% or 6.53 years of their expected remaining life span. Age, sex and postoperative intraocular pressure control did not predict survival. The only predictor of improved survival was a preoperative visual acuity of 6/48 or better. These patients lost 21% (or 2.43 years) of expected remaining life compared to 62% (or 10.78 years) in those patients who had a presenting visual acuity of 6/60 or worse. Conclusions: Patients with neovascular glaucoma had a markedly reduced life expectancy, which has improved in recent years when compared to that of the normal sex and age-matched New Zealand population. Patients presenting with better vision (6/48 or better) survived significantly longer than those presenting with poorer vision. [ABSTRACT FROM AUTHOR]

The myopic eye is generally considered to be a vulnerable eye and, at levels greater than 6 D, one that is especially susceptible to a range of ocular pathologies. There is concern therefore that the prevalence of myopia in young adolescent eyes has increased substantially over recent decades and is now approaching 10−25% and 60−80%, respectively, in industrialized societies of the West and East. Whereas it is clear that the major structural correlate of myopia is longitudinal elongation of the posterior vitreous chamber, other potential correlates include profiles of lenticular and corneal power, the relationship between longitudinal and transverse vitreous chamber dimensions and ocular volume. The most potent predictors for juvenile-onset myopia continue to be a refractive error ≤+0.50 D at 5 years of age and family history. Significant and continuing progress is being made on the genetic characteristics of high myopia with at least four chromosomes currently identified. Twin studies and genetic modelling have computed a heritability index of at least 80% across the whole ametropic continuum. The high index does not, however, preclude an environmental precursor, sustained near work with high cognitive demand being the most likely. The significance of associations between accommodation, oculomotor dysfunction and human myopia is equivocal despite animal models that have demonstrated that sustained hyperopic defocus can induce vitreous chamber growth. Recent optical and pharmaceutical approaches to the reduction of myopia progression in children are likely precedents for future research, for example progressive addition spectacle lens trials and the use of the topical M1 muscarinic antagonist pirenzepine. [ABSTRACT FROM AUTHOR]

Abstract Purpose: A comparison of axial length estimates using applanation A-scan ultrasound and the Zeiss IOLMaster was conducted. The accuracy in predicting postoperative refraction determined by each method was also compared. Methods: A cross-sectional study was performed on 51 eyes in 46 patients presenting to clinical practice for cataract surgery assessment. Preoperative measurement of axial length was performed with applanation ultrasound and the IOLMaster. The IOLMaster measurements were used to determine the intraocular lens power based on the SRK/T formula. Postoperative refractive outcomes were obtained and spherical equivalent calculated and compared to the predicted refractive error with each biometric method. Results: On average the axial lengths measured by the IOLMaster were longer by 0.15 mm compared to ultrasound biometry (P < 0.01). Using the IOLMaster over applanation ultrasound biometry significantly improved the postoperative refractive outcome from 0.65 D to 0.42 D (P = 0.011). Conclusions: The IOLMaster provides an accurate axial length measurement and results in accurate intraocular lens power calculation based on the SRK/T formula. It is quick and easy to use and provides a non-contact technique with no risk of infection or corneal abrasion. [ABSTRACT FROM AUTHOR]

Background: The ability to perform biometry accurately on a dilated pupil can greatly facilitate the efficiency of a cataract service as it can be done on the day of surgery. The purpose of this study was to assess the repeatability of axial length (AL) calculations in undilated pupils and measure the difference in predicted and actual refractive outcomes in dilated pupils compared with undilated pupils. Methods: First, intraobserver repeatability was assessed by taking two consecutive recordings of AL using applanation A-scan ultrasonography in undilated pupils in 21 eyes. The mean AL for each eye was compared with a measurement made following pupil dilatation. Second, we audited the mean spherical equivalent refractive errors following routine cataract surgery in 38 patients with undilated pupils and 36 patients with dilated pupils. Results: The mean difference in intraobserver measurements was −0.05 mm (standard deviation [SD] 0.15) with pupils undilated. Following pupil dilatation, the mean dilated AL differed from the mean undilated AL reading by only 0.03 mm ( P > 0.05). The mean differences between planned and actual refractive error were 0.71D (SD 0.54) and 0.55D (SD 0.41) in dilated and undilated patients, respectively. This was not statistically significant ( P > 0.05). The range of differences between target and actual refraction was −1.45D to 2.70D for undilated patients and −1.88D to 1.18D in dilated patients. Conclusion: Although there was a greater spread of postoperative refractive errors in the dilated group, there were no statistically or clinically significant differences in postoperative refractive errors between the two categories of patients. Our study shows that applanation biometry may be safely performed for the purpose of cataract surgery after pupil dilatation. [ABSTRACT FROM AUTHOR]

The article examine the patient demographics, visual and surgical outcomes of a cohort undergoing Small Incision Cataract Surgery (SICS) at a Pacific regional ophthalmic training facility. It is mentioned that ophthalmic examination, including pachymetry and macular Optical Coherence Tomography (OCT). The article adds that refinements in biometric and surgical techniques may allow a greater proportion of patients to achieve good unaided vision.

The authors discuss the prevalence of angle closure disease in Asia, particularly in developing countries. They state that the biometric risk factors for the disease include axial length, anterior chamber depth, and lens thickness. Furthermore, they note that the changes in biometry will not lead to the differences in genetic or non-biomtric risk factors for the disease.

A letter to the editor is presented in response to the article regarding intraocular pressure (IOP) reduction and anterior segment biometric parameters by R. Y. Lee and colleagues that appeared in the previous issue of the journal.