Automated static perimetry: the influence of myopia and its method of correction

Aging-associated changes of optical coherence tomography-measured ganglion cell-related retinal layer thickness and visual sensitivity in normal Japanese

PURPOSE

To report aging-associated change rates in circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and macular ganglion cell-inner plexiform layer and complex thickness (MGCIPLT, MGCCT) in normal Japanese eyes and to compare the data in linear scaled visual field (VF) sensitivity of central 4 points of Humphrey Field Analyzer (HFA) 24-2 test (VF4TestPoints) to that in MGCIPLT in four 0.6-mm-diameter circles corresponding to the four central points of HFA 24-2 adjusted for retinal ganglion cell displacement (GCIPLT4TestPoints).

STUDY DESIGN

Prospective observational study METHODS: HFA 24-2 tests and spectral-domain optical coherence tomography (SD-OCT) measurements of cpRNFLT, MGCIPLT, MGCCT and GCIPLT4TestPoints were performed every 3 months for 3 years in 73 eyes of 37 healthy Japanese with mean age of 50.4 years. The time changes of SD-OCT-measured parameters and VF4TestPoints were analyzed using a linear mixed model.

RESULTS

The aging-associated change rates were -0.064 μm/year for MGCIPLT and and -0.095 for MGCCT (P=0.020 and 0.017), but could not be detected for cpRNFLT. They accelerated with aging at -0.009μm/year/year of age for MGCIPLT (P<0.001), at 0.011 for MGCCT (P<0.001) and at 0.013 for cpRNFLT(0.031). The aging-associated decline of -82.1 [1/Lambert]/year of VF4TestPoints corresponded to -0.095 μm/year of GCIPLT4TestPoints.

CONCLUSION

We report that aging-associated change rates of cpRNFLT, MGCIPLT and MGCCT in normal Japanese eyes were found to be significantly accelerated along with aging. Relationship between VF sensitivity decline rates and SD-OCT measured GCIPLT decline rates during physiological aging in the corresponding parafoveal retinal areas are also documented.

Optic neuropathy in high myopia: Glaucoma or high myopia or both?

Due to the increasing prevalence of high myopia around the world, structural and functional damages to the optic nerve in high myopia has recently attracted much attention. Evidence has shown that high myopia is related to the development of glaucomatous or glaucoma-like optic neuropathy, and that both have many common features. These similarities often pose a diagnostic challenge that will affect the future management of glaucoma suspects in high myopia. In this review, we summarize similarities and differences in optic neuropathy arising from non-pathologic high myopia and glaucoma by considering their respective structural and functional characteristics on fundus photography, optical coherence tomography scanning, and visual field tests. These features may also help to distinguish the underlying mechanisms of the optic neuropathies and to determine management strategies for patients with high myopia and glaucoma.

Importance of Pattern Standard Deviation of Humphrey 10-2 Visual Field to Evaluate Central Visual Function in Patients with Early-Stage Glaucoma

To explore various parameters that can evaluate the central visual impairment in patients with early-stage glaucoma, we included patients into a study with central visual impairments with an MD value greater than -6.0 dB on the 24-2 VF test. A possible association between structural parameters acquired by OCT and functional parameters of VF and PERG was determined. A total of 70 eyes of patients with suspected glaucoma or NTG underwent VF, OCT, and PERG examinations. The patients were classified into two groups according to the MD of the 24-2 VF test. We used Pearson correlation analysis to evaluate the relationships between GCIPL thickness/RNFL thickness and visual functional parameters, such as PERG and perimetry. Linear regression analyses were conducted to evaluate the significant factors affecting the PSD of VF 10-2. In the low MD group, the P50 amplitude presented significant correlations (r = 0.346, p = 0.048) with GCIPL thickness. In the correlation analysis of the high MD group, it was found that only the PSD of 10-2 uniquely presented borderline significant correlations with GCIPL thickness (r = -0.327, p = 0.055), and no other functional parameter showed significant correlation. Univariate and multivariate analyses revealed that GCIPL thickness was significantly associated with a PSD of 10-2 VF (p < 0.001 and 0.013, respectively). Among various parameters, the P50 amplitude and 10-2 PSD demonstrated statistically borderline significant structure-function relationships with GCIPL thickness in early-stage glaucoma.

Update on the diagnosis and treatment of normotensive glaucoma

The increased Knowledge of the multifactorial origin of glaucoma, and especially the vascular involvement in normotensive glaucoma, can be seen in the high number of publications on this subject in recent years, which obliges us to review its diagnosis and treatment.

Myopic tilted disc: Mechanism, clinical significance, and public health implication

Myopic tilted disc is a common structural change of myopic eyes. With advancing ocular imaging technology, the associated structural changes of the eye, particularly the optic nerve head, have been extensively studied. These structural changes may increase patients' susceptibility to axonal damage and the risk of developing serious optic neuropathies including glaucoma. They also lead to diagnostic difficulties of disease suspects and treatment dilemmas of patients, which implicate clinical practice and subsequently the health care system. In the context of the mounting prevalence of myopia worldwide and its implications to irreversible visual impairment and blindness, it is essential to gain a thorough understanding of the structural changes of myopia. Myopic tilted disc has been extensively investigated by different study groups. However, generalizing the knowledge could be difficult because of the variable definitions of myopic tilted disc utilized in these studies and the complexities of the changes. The current review aimed to clarify the concepts and discuss various aspects of myopic tilted disc, including the definitions, association with other myopia-related changes, mechanism of tilted disc development, structural and functional changes, and clinical implications.

Classification of Visual Field Abnormalities in Highly Myopic Eyes without Pathologic Change

PURPOSE

To develop a classification system of visual field (VF) abnormalities in highly myopic eyes with and without glaucoma.

DESIGN

Secondary analysis of VF data from a longitudinal cohort study.

PARTICIPANTS

One thousand eight hundred ninety-three VF tests from 1302 eyes (825 individuals).

METHODS

All participants underwent VF testing (Humphrey 24-2 Swedish interactive threshold algorithm standard program; Carl Zeiss Meditec) and detailed ophthalmic examination. A comprehensive set of VF defect patterns was defined via observation of the 1893 VF reports, literature review, and consensus meetings. The classification system comprised 4 major types of VF patterns, including normal type, glaucoma-like defects (paracentral defect, nasal step, partial arcuate defect, arcuate defect), high myopia-related defects (enlarged blind spot, vertical step, partial peripheral rim, nonspecific defect), and combined defects (nasal step with enlarged blind spot). A subset (n = 1000) of the VFs was used to evaluate the interobserver and intraobserver agreement and weighted κ values of the classification system by 2 trained readers. The prevalence of various VF patterns and their associated factors were determined.

MAIN OUTCOME MEASURES

The classification of VF in highly myopic eyes and its associated risk factors.

RESULTS

We found that normal type, glaucoma-like defects, high myopia-related defects, and combined defects accounted for 74.1%, 10.8%, 15.0%, and 0.1% of all unique VF tests, respectively. The interobserver and intraobserver agreements were > 89%, and the corresponding κ values were 0.86 or more between readers. Both glaucoma-like and high myopia-related VF defects were associated with older age (odds ratios [ORs], 1.07 [95% confidence interval (CI), 1.04-1.10; P < 0.001] and 1.06 [95% CI, 1.04-1.10; P < 0.001]) and longer axial length (ORs, 1.65 [95% CI, 1.32-2.07; P < 0.001] and 1.37 [95% CI, 1.11-1.68; P = 0.003]). Longer axial length showed a stronger effect on the prevalence of glaucoma-like VF defects than on the prevalence of high myopia-related VF defects (P = 0.036).

CONCLUSIONS

We propose a new and reproducible classification system of VF abnormalities for nonpathologic high myopia. Applying a comprehensive classification system will facilitate communication and comparison of findings among studies.

Comparison of the structure-function relationship between compass microperimetry and Humphrey field analyser in myopic open-angle glaucoma eyes

BACKGROUND/AIMS

To compare the structure-function relationship between compass microperimetry (CMP; CenterVue, Padova, Italy) and Humphrey field analyser (HFA; Carl Zeiss Meditec, Dublin, California, USA) in open-angle glaucoma (OAG) eyes with myopia.

METHODS

Circumpapillary retinal nerve fibre layer thickness (cpRNFLT) and visual field (VF) mean sensitivity (MS) were obtained in 90 OAG subjects using the optical coherence tomography, CMP and HFA in a random order. The global and sectoral structure-function relationships between the cpRNFLT and VFMS were assessed with different VF devices (CMP vs HHA) in OAG eyes with and without myopia.

RESULTS

Overall, the global and regional structure-function relationships between the two devices did not show significant differences except for the superotemporal sector. In the myopic subgroup, the global association between the average cpRNFLT and VFMS_CMP was significantly stronger than that between the average cpRNFLT and VFMS_HFA (r=0.806 vs. 0.720, p=0.035). The presence of myopia and higher global cpRNFLT were significantly associated with the greater global VFMS differences between the two devices (p<0.05).

CONCLUSION

In general, structure-function relationship is similar between CMP and HFA in OAG eyes. However, the global structure-function relationship is significantly stronger with CMP than with HFA in OAG eyes with myopia.

Effects of Physiologic Myopia and Aging on Visual Fields in Normal Eyes

PURPOSE

The purpose of this study was to investigate how mild-to-moderate myopia and aging affect visual field sensitivity (VF-S) in normal eyes, correcting for effects of each.

DESIGN

Combined cross-sectional and cohort study.

METHODS

Two normal groups, a cross-sectional group (n = 703; 1,051 eyes; mean age, 52.6 years) and a longitudinal group (n = 44; 83 eyes; mean age, 52.3 years; follow-up, 4.2 years; VF tests, 12) were included. In the cross-sectional group, the mean VF-S of the entire field and 3 disc portion-oriented subfields of the Humphrey Field Analyzer 24-2 program were correlated with subjects' age, axial length (AL), disc, rim and β-peripapillary area, and disc ovality and torsion, using linear mixed-regression models. Their time changes in the longitudinal group were correlated with time, subjects' ages, and AL using linear mixed-regression models.

RESULTS

In the cross-sectional group, the VF-S correlated negatively with age (-0.081 decibel [dB]/year; P < .001), which was more negative (P = .020) in the midperipheral than the central subfield, and with AL (P = .049) without intersubfield differences. In the longitudinal group, no changes in the ocular media were significant, and the VF-S declined by 0.074 dB/year (P = .007), which accelerated with higher age (P < .002) and baseline VF-S (P < .001) without intersubfield differences. The AL showed little effects on the VF-S longitudinal changes.

CONCLUSIONS

In normal eyes with mild-to-moderate myopia, the VF-S was lower subfield-independently with longer AL, whereas the AL had little effect on the aging-associated VF-S reduction. The VF-S decreased with aging with intersubfield differences. The aging-associated VF-S reduction accelerated with higher age, to which the ocular media changes were unrelated.

Applications of the isolated-check visual evoked potential in primary open angle glaucoma with or without high myopia

AIM

To explore the diagnostic performance of isolated-check visual evoked potential (icVEP) for primary open angle glaucoma (POAG) in both highly myopic and non-highly myopic populations and compare it with those of optical coherence tomography (OCT) and Heidelberg retinal tomography (HRT) parameters.

METHODS

A total of 126 participants were recruited, including 31 highly myopic participants with POAG (HM-POAG), 36 non-highly myopic participants with POAG (NHM-POAG), 25 highly myopic participants without POAG (HM) and 34 controls without high myopia (Normal). All the participants underwent a complete ophthalmic examination. The signal-to-noise ratio (SNR) was used to assess the icVEP. Both qualitative and quantitative diagnostic performances of OCT, HRT and the icVEP were analyzed and compared.

RESULTS

Based on the criterion of SNR≤1, the diagnostic performance of the icVEP in highly myopic subjects [area under the receiver operating characteristic curve (AUC)=0.862] was better than that in non-highly myopic subjects (AUC=0.789), and the SNR had fairly good specificity. In distinguishing the HM-POAG and HM groups, the AUC of the SNR was not different from those of the OCT and HRT parameters (P>0.05) in either the qualitative or quantitative comparison. In the qualitative analysis, the icVEP showed good consistency with damage to the central 10° of the visual field (kappa=0.695-0.747, P<0.001).

CONCLUSION

The icVEP has the potential to discriminate individuals with and without POAG, especially in populations with high myopia.

Visual field defects and myopic macular degeneration in Singapore adults with high myopia

AIMS

To characterise the association between visual field (VF) defects and myopic macular degeneration (MMD) in highly myopic adults without glaucoma.

METHODS

Participants (n=106; 181 eyes) with high myopia (HM; spherical equivalent ≤-5.0 D or axial length (AL) ≥26 mm), after excluding glaucoma and glaucoma suspects, from the Singapore Epidemiology of Eye Diseases-HM study were included in this cross-sectional study. Humphrey VF (central 24-2 threshold), cup-disc ratio (CDR) and intraocular pressure (IOP) measurements were performed. Mean deviation (MD) and pattern SD (PSD), VF defects (normal or abnormal; p<0.05 in ≥3 non-edge contiguous locations) and pattern (eg, generalised sensitivity loss) were analysed. MMD presence was diagnosed from fundus photographs. Generalised estimating equations were used for analysing factors (MD, PSD, VF defects, CDR and IOP) associated with MMD.

RESULTS

Mean age was 55.4±9.9 years and 51.9% were women (AL=26.7±1.1 mm). MMD eyes had lower MD (-3.8±2.9 dB vs -1.1±1.4 dB) and higher PSD (2.8±1.7 dB vs 1.7±0.6 dB). A higher percentage of MMD eyes (n=48) had abnormal VF (62.5% vs 28.6%; p<0.001) compared with no MMD (n=133 eyes). VF pattern in MMD eyes was significantly different from eyes without MMD (p=0.001) with greater generalised sensitivity loss (53.3% vs 10.5%) and arcuate defects (16.7% vs 10.5%). In multivariate analyses, MD (OR=1.52) and PSD (OR=1.67) were significantly (p=0.003) associated with MMD, but VF defects were not associated with MMD.

CONCLUSION

Highly myopic adults with MMD may have VF loss when compared with highly myopic patients without MMD even in adults without glaucoma.

Comparing Structure-Function Relationships Based on Drasdo's and Sjöstrand's Retinal Ganglion Cell Displacement Models

Purpose

To compare structure-function relationships based on the Drasdo and Sjöstrand retinal ganglion cell displacement models.

Methods

Single eyes from 305 patients with glaucoma and 55 heathy participants were included in this multicenter, cross-sectional study. The ganglion cell and inner plexiform layer (GCIPL) thickness was measured using spectral domain optical coherence tomography. Visual field measurements were performed using the Humphrey 10-2 test. All A-scan pixels (128 × 512 pixels) were allocated to the closest 10-2 location with both displacement models using degree and millimeter scales. Structure-function relationships were investigated between GCIPL thickness and corresponding visual sensitivity in nonlong (160 eyes) and long (200 eyes) axial length (AL) groups.

Results

In both the nonlong and long AL groups, compared with the no-displacement model, both the Drasdo and the Sjöstrand models showed that the structure-function relationship around the fovea improved (P < 0.05). The magnitude of improvement in the area was either comparable between the model or was larger for the Drasdo model than the Sjöstrand model (P < 0.05). Meanwhile, structure-function relationships outside the innermost retinal region that were based on the Drasdo and Sjöstrand models were comparable to or were even worse than (in the case of the Drasdo model) those obtained using the no-displacement model.

Conclusions

Structure-function relationships evaluated based on both the Drasdo and Sjöstrand models significantly improved around the fovea, particularly when using the Drasdo model. This was not the case in other areas.

Thinner retinal nerve fibre layer in healthy myopic eyes with thinner central corneal thickness

PURPOSE

Thinner central corneal thickness (CCT) is a risk factor for conversion from ocular hypertension to glaucoma and for disease progression. However, little is known about the relationship between CCT and characteristics of the optic nerve and the retinal nerve fibre layer (RNFL) in non-glaucomatous eyes. Because myopic eyes may pose diagnostic challenges when assessed for glaucoma, characterising the relationship between CCT and RNFL in these eyes is clinically relevant. Our aim was to investigate the relationship between CCT and RNFL thickness in non-glaucomatous eyes with small/moderate myopia.

METHODS

This was a single-centre, observational, prospective, assessor-masked study. Consecutive eligible patients (myopia ≤ - 6.0 dioptres, astigmatism ≤ 2.0 dioptres) without other ocular or neurodegenerative diseases were included. Based on their CCT, the participants were allocated to group 1 (CCT > 555 μm) or group 2 (CCT < 555 μm). Peripapillary RNFL measurements were performed by a masked observer using the Spectralis OCT platform.

RESULTS

Sixty eyes were included in group 1 and 63 in group 2. The CCT in the two groups was significantly different (584.27 ± 22.8 μm vs 522.23 ± 20.03 μm, p = 0.0001). There were no other significant differences in the groups in terms of age, refraction, or intraocular pressure. The peripapillary RNFL thickness was higher (all p < 0.005) in group 1 at several sectors: superior-temporal, inferior-temporal, inferior-nasal, and average. A significant positive correlation between CCT and average RNFL thickness was found for the whole population (r = 0.31, p = 0.0001).

CONCLUSION

Otherwise, healthy myopes with thinner CCT have thinner RNFL compared with participants of similar age and refraction with thicker CCT.

Impact of myopia on the association of long-term intraocular pressure fluctuation with the rate of progression in normal-tension glaucoma

BACKGROUND/AIMS

To investigate whether the association of long-term intraocular pressure (IOP) fluctuation with the rate of progression of normal-tension glaucoma (NTG) differs between myopia and non-myopia.

METHODS

The medical records of 65 myopic NTG (axial length (AL) > 24.0 mm) and 64 non-myopic NTG eyes (AL < 24.0 mm), who had been treated with topical medications for more than 5 years, were reviewed. Multiple linear regression models were fitted to analyse the relationships of the slope of mean deviation (MD) or visual field index (VFI) with the clinical factors, including the interactions with myopia.

RESULTS

The average follow-up period was 8.3 years. Twenty-two (22) non-myopic eyes (34.4%) and 27 myopic eyes (41.5%) showed NTG progression (p=0.511). The interaction of myopia with IOP fluctuation was a significant factor regarding both MD and VFI slope (p=0.002, 0.024, respectively); stratified analyses suggested that the risk effect of IOP fluctuation was significant only in myopic NTG in terms of both MD (β= -1.27, p=0.003) and VFI slope (β=-2.32, p=0.011).

CONCLUSION

Long-term IOP fluctuation was significantly related to faster visual field progression in myopic NTG eyes, compared with non-myopic NTG eyes.

Different Disc Characteristics Associated With High Myopia and the Location of Glaucomatous Damage in Primary Open-Angle Glaucoma and Normal-Tension Glaucoma

PRéCIS:: Disc tilt is a characteristic of high myopia and related to lower wedge-shaped retinal nerve fiber layer (RNFL) defects in normal-tension glaucoma (NTG). In primary open-angle glaucoma (POAG), the direction of disc torsion corresponds to the location of wedge-shaped RNFL defects.

PURPOSE

To evaluate the disc characteristics in high myopia and the relationships between disc tilt and torsion and the location of wedge-shaped RNFL defects in primary POAG and NTG.

MATERIALS AND METHODS

The differences in disc properties and clinical characteristics between POAG (n=53) and NTG (n=82), and between high myopic (<-6 D, n=77) and non-high myopic (≥-6 D, n=58) glaucoma, were investigated. The association between disc tilt and torsion and the location of wedge-shaped RNFL defects in POAG and NTG were assessed by univariate and multivariate logistic regression analyses.

RESULTS

In NTG, but not in POAG, high myopia eyes had significantly smaller discs, a lower tilt ratio (0.73±0.09), and more disc tilt (56.5%) than did non-high myopia eyes (0.80±0.09, 33.3%). In POAG, eyes with lower wedge-shaped RNFL defects had a significantly smaller torsion angle (-5.44±19.62 degrees, inferior disc torsion) than did eyes with upper defects (9.70±23.62 degrees, superior disc torsion; P=0.014). In NTG, a significantly decreased tilt ratio (0.74±0.93; P=0.001) and more disc tilt (55.9%, P=0.005) were found in eyes with lower wedge-shaped RNFL defects than in eyes with upper defects (0.81±0.09; 21.7%). The torsion degree and tilt ratio were the only factors associated with the location of wedge-shaped RNFL defects in POAG and NTG, respectively.

CONCLUSIONS

In NTG, smaller and tilted discs were the characteristics of high myopia. Disc tilt was associated with lower wedge-shaped RNFL defects. In POAG, the direction of disc torsion corresponded to the location of the wedge-shaped RNFL defects.

Posterior scleral deformation and autonomic dysfunction in normal tension glaucoma

In meta-analyses, it has been reported that myopia is a risk factor for glaucoma and there is increasing evidence that autonomic dysfunction causing vascular dysregulation or perfusion dysfunction is considered an important factor in the progression of glaucoma. There have been experimental studies to find out the association between autonomic nervous system and ocular growth, but no clinical study yet has evaluated the relationship between them. Therefore, we enrolled 208 open angle glaucoma patients and measured heart-rate-variability(HRV). We used the standard deviation value of the qualified normal to normal intervals (SDNN) parameter of HRV, which is considered an autonomic influence index and characterized the total effect of the regulation of autonomic blood circulation. Patients were classified into the two groups according to SDNN: those with low possibility of autonomic dysfunction (LoAD group) and those with high possibility of autonomic dysfunction (HiAD group). We evaluated myopic features employing a 'posterior scleral profile' identified by the disc tilt ratio, disc torsion, fovea-BMO center (FoBMO) angle and peripapapillary area(PPA) to disc ratio. HiAD group showed higher values than LoAD group in posterior scleral deformation profile such like axial length, disc tilt, torsion degree. We suggest the possibility of association between myopic deformation and autonomic dysfunction.

Machine learning classifiers-based prediction of normal-tension glaucoma progression in young myopic patients

PURPOSE

To assess the performance of machine learning classifiers for prediction of progression of normal-tension glaucoma (NTG) in young myopic patients.

STUDY DESIGN

Cross-sectional study.

METHODS

One hundred and fifty-five eyes of 155 myopic NTG patients (axial length [AL] ≥ 24.00 mm and refractive error ≤ - 3.0 D) between the ages of 20 and 40 were enrolled and divided into training (110) and test (45) sets. Sixty-five eyes showed glaucoma progression as defined by standard automated perimetry, while 91 eyes (nonprogressors) had been stable over the course of a follow-up period of at least 3 years. Two machine learning classifiers were built using the random forest and extremely randomized trees (extra-trees) models. Baseline clinical measurements obtained only at the initial visit were used as input features. The area under the receiver operating characteristic curve (AUC) was calculated to evaluate the accuracy of prediction.

RESULTS

Mean age and AL did not significantly differ between the 2 groups on either the training or the test set. The extra-trees model achieved an AUC of 0.881 [95% CI 0.814-0.945], higher than that of the random forest model (0.811 [0.731-0.888]; P = 0.010). The extra-trees model also outperformed all the clinical measurements for prediction of NTG progression, including average macular ganglion cell-inner plexiform layer thickness (0.735 [0.639-0.831]) and average circumpapillary retinal nerve fiber layer thickness (0.691 [0.590-0.792]; both P < 0.001).

CONCLUSIONS

In young myopic patients, the machine learning classifier with the extra-trees model can predict glaucomatous progression more effectively than clinical diagnostic parameters.

Neutralizing Peripheral Refraction Eliminates Refractive Scotomata in Tilted Disc Syndrome

SIGNIFICANCE

We demonstrate that the visual field defects in patients with tilted disc syndrome can be reduced or eliminated by neutralizing the peripheral scotoma in the area of posterior retinal bowing, which may allow differentiation between a congenital anomaly and acquired pathology.

PURPOSE

Tilted disc syndrome is a congenital and unchanging condition that may present with visual field defects mimicking loss seen in neurological diseases, such as transsynaptic retrograde degeneration. Our purpose was to systematically investigate the ability of a neutralized peripheral refraction to eliminate refractive visual field defects seen in tilted disc syndrome. This was compared with the same technique performed on patients with neurological deficits.

METHODS

The Humphrey Field Analyzer was used to measure sensitivities across the 30-2 test grid in 14 patients with tilted disc syndrome using four refractive corrections: habitual near correction and with an additional -1.00, -2.00 or -3.00 D negative lens added as correction lenses. Peripheral refractive errors along the horizontal meridian were determined using peripheral retinoscopy and thus allowed calculation of residual peripheral refraction with different levels of refractive correction. Visual field defects were assessed qualitatively and quantitatively using sensitivities and probability scores in both patient groups.

RESULTS

A smaller residual refractive error after the application of negative addition lenses correlated with improvement in visual field defects in terms of sensitivity and probability scores in patients with tilted disc syndrome. Patients with established neurological deficits (retrograde degeneration) showed improvement in sensitivities but not in probability scores.

CONCLUSIONS

Neutralizing the refractive error at the region of posterior retinal bowing due to tilted disc syndrome reduces the apparent visual field defect. This may be a useful and rapid test to help differentiate between tilted disc syndrome and other pathological causes of visual field defects such as neurological deficits.

Glaucoma in myopia: diagnostic dilemmas

Myopic eyes have an increased risk of glaucoma. However, glaucomatous changes in a myopic eye are often difficult to detect. Classic structural and functional investigations to diagnose glaucoma may be confounded by myopia. Here, we identify some of the common pitfalls in interpreting these structural parameters, and the possible solutions that could be taken to overcome them. For instance, in myopic eyes, we discuss the limitations and potential sources of error when using neuroretinal rim parameters, and retinal nerve fibre layer and ganglion cell-inner plexiform layer thickness measurements. In addition, we also review new developments and potential adjuncts in structural imaging such as the assessment of the retinal nerve fibre layer texture, and the examination of the microcirculation of the optic nerve head using optical coherence tomography angiography. For the functional assessment of glaucoma, we discuss perimetric strategies that may aid in detecting characteristic visual field defects in myopic glaucoma. Ultimately, the evaluation of glaucoma in myopia requires a multimodal approach, to allow correlation between structural and functional assessments. This review provides overview on how to navigate this diagnostic dilemma.

Early diagnostic parameters of glaucoma in high myopes

PURPOSE

The goal of this study was to assess changes in OCT parameters occurring in high myopic glaucoma patients, so as to enable early diagnosis and prevention of progressive glaucomatous damage. It was performed at the department of ophthalmology, Kasr Alainy Hospital, Cairo University, over a twenty-month period.

METHODS

This study was a cross-sectional randomized single blinded study. It included 62 eyes of highly myopic individuals. Patients were divided into 2 groups: Group A included myopic non-glaucomatous individuals, and Group B included the myopic glaucoma patients. All patients had a full ophthalmological examination, as well as OCT assessment of the RNFL, GCC and ONH parameters. The VF was tested as well as AXL and CCT. Correlation of the data was performed.

RESULTS

Regarding the GLV, its mean in group A was 11.88±6.71% versus 19.69±9.69% in group B; the difference between both groups was statistically significant (P=0.001). Regarding the cup area, the mean in group A was 0.51±0.41mm², while that in group B was 1.25±0.72mm²; the difference between both groups was statistically significant (P<0.001).

CONCLUSION

The ONH parameter, cup area, and the GCC parameter, GLV, are key parameters in supporting the diagnosis of glaucoma in myopic patients. Other parameters measured by OCT, such as inferior RNFL thickness, FLV, and C/D ratio, could aid in diagnosis as well.

The Longitudinal Danish High Myopia Study, Cohort 1948: at age 66 years visual ability is only occasionally affected by visual field defects

PURPOSE

A descriptive study on visual fields, as part of a 50-year follow-up of high myopia in an unselected cohort-based Danish sample, now aged 66 years.

METHODS

In a Copenhagen 1948 birth cohort (n = 9243), 39 individuals aged 14 years were identified with myopia of at least -6 D, and with regular clinical follow-ups since then. In 2002 (n = 34, age 54 years) and 2008 (n = 32, age 60), the individual ambulatory visual field was outlined by kinetic Goldmann large object perimetry (IV or V,4e). At age 66 years, 28 attended for the 2014-2015 follow-up, at which smaller Goldmann objects (II and I,4e) were added, further to identify relative defects.

RESULTS

Repeated large object perimetry disclosed statistically significant general peripheral narrowing over the 12-13-year test period, though slight and without practical implications. Two new cases showing absolute defects were however added to the three already known. The addition of small Goldmann objects disclosed relative defects in another eight participants, in some to suggest a refraction-related pattern (fundus ectasia; uncorrected high myopia). However, comparing eyes with and without defects, statistical importance could not be attached to the degree of myopia, fundus ectasia or optic disc morphology (χ² , n.s.).

CONCLUSION

(i) Serial large object Goldmann isopters over the 'senior' decade up to age 66 demonstrated a slight general peripheral narrowing by age of visual fields in high myopia. (ii) Overall 42% of the participants had absolute or relative defects (in 5 and 8, respectively), however, without socio-visual consequences when binocular. (iii) Visual field loss by age still appears a minor issue in clinically unselected high myopia.

Properties of pattern standard deviation in open-angle glaucoma patients with hemi-optic neuropathy and bi-optic neuropathy

Purpose

To evaluate the properties of pattern standard deviation (PSD) according to localization of the glaucomatous optic neuropathy.

Methods

We enrolled 242 eyes of 242 patients with primary open-angle glaucoma, with a best-corrected visual acuity ≥ 20/25, and no media opacity. Patients were examined via dilated fundus photography, spectral-domain optical coherence tomography, and Humphrey visual field examination, and divided into those with hemi-optic neuropathy (superior or inferior) and bi-optic neuropathy (both superior and inferior). We assessed the relationship between mean deviation (MD) and PSD. Using broken stick regression analysis, the tipping point was identified, i.e., the point at which MD became significantly associated with a paradoxical reversal of PSD.

Results

In 91 patients with hemi-optic neuropathy, PSD showed a strong correlation with MD (r = −0.973, β = −0.965, p < 0.001). The difference between MD and PSD (“−MD−PSD”) was constant (mean, −0.32 dB; 95% confidence interval, −2.48~1.84 dB) regardless of visual field defect severity. However, in 151 patients with bi-optic neuropathy, a negative correlation was evident between “−MD−PSD” and MD (r² = 0.907, p < 0.001). Overall, the MD tipping point was −14.0 dB, which was close to approximately 50% damage of the entire visual field (p < 0.001).

Conclusions

Although a false decrease of PSD usually begins at approximately 50% visual field damage, in patients with hemi-optic neuropathy, the PSD shows no paradoxical decrease and shows a linear correlation with MD.

Visual field assessment in high myopia with and without tilted optic disc

BACKGROUND

The aim was to evaluate the effect of the tilted optic disc on the visual field in highly myopic eyes.

METHODS

A total of 58 eyes from 58 highly myopic individuals underwent detailed ophthalmic examination and were categorised into two groups according to the presence of a tilted optic disc. The visual field of 20 eyes (mean age of 28.95 ± 7.22 years) with tilted optic discs were compared with 38 eyes (mean age of 27.87 ± 6.08 years) of control subjects without tilted optic discs using the 30-2 SITA standard protocol with a Humphrey Field Analyzer - HFA II-i. Optic disc tilt was assessed from retinal photographs exported to Adobe Photoshop software. Disc ovality was assessed using the ratio of minimum to maximum disc diameter. A ratio of up to 0.80 was considered a tilted optic disc.

RESULTS

Foveal threshold sensitivity showed no statistically significant difference between tilted and non-tilted groups (35.16 ± 2.71 dB versus 35.37 ± 2.35 dB, p = 0.76). The mean deviation was -3.29 ± 2.03 dB in the tilted group and -3.49 ± 2.56 dB in the non-tilted group (p = 0.77). Additionally, there were no significant differences in the average deviation between the two groups in four quadrants and four hemifields; however, the lowest average deviation was observed in the superotemporal quadrant in the tilted group (-4.54 ± 3.16 dB). In the non-tilted group, 29 per cent had no visual field defect, 24 per cent had an arcuate scotoma and 20 per cent had generalised depression. In the tilted group, 30 per cent had an arcuate scotoma, 30 per cent had generalised depression and 13 per cent had no visual field defect. Other visual field defects occurred at frequencies less than 15 per cent in both groups.

CONCLUSIONS

The investigation of visual field patterns may be more appropriate than quantitative indices (for example, total mean deviation, foveal threshold sensitivity, average deviation) to assess the visual field in highly myopic patients with tilted optic discs.

The Relationship between Visual Field Global Indices and Retinal Nerve Fiber Layer Thickness in Healthy Myopes

The aim of the current study was to investigate the association between the thickness of the retinal nerve fiber layer (RNFL) and central visual field indices in otherwise healthy myopes. In total, 57 otherwise healthy subjects were cross-sectionally studied. General ophthalmic examinations, refractive measurements, RNFL thickness by spectral domain optical coherence tomography (OCT), and central visual fields were examined. Linear models were used to assess the associations. In this young and mid-aged population, the mean spherical equivalent was −4.79 (SD 1.66) and −4.59 (SD 1.88) diopters in the right and left eyes, respectively. Approximately 7% to 14% of the eyes showed the average RNFL thickness out of the normal range. The temporal RNFL was remarkably thicker, whereas the nasal RNFL was thinner. The higher the refractive error, the thinner the RNFL thickness. A thicker overall RNFL was significantly associated with decreased mean sensitivity and increased mean defect, and further adjustments for age, sex, refractive error, optic disk area, or ocular magnification did not change the association. Although nonpathologic myopia does not significantly affect central visual field global indices, its effects on the RNFL may be linked with performance on the central visual field test.

Effect of Optical Defocus on the Kinetic Perimetry in Young Myopic Participants

PURPOSE

The prospective study evaluated the effects of optical defocus on kinetic sensitivity using automated kinetic perimetry.

MATERIALS AND METHODS

The 17 eyes of 17 healthy young participants were evaluated. All of the participants had myopia (≥ -5.00 D) and mild to no astigmatism (<1.00 D). Automated kinetic perimetry was performed using the Octopus 900 perimeter with Goldmann stimuli III4e, I4e, I3e, I2e, and I1e, with stimuli presented at 14 predetermined meridians, and a velocity of 3°/s. Optical defocus was induced with soft contact lenses, and varied in 1 D increments between 0 and +7 D. Kinetic sensitivity at each defocus was evaluated and compared to sensitivity with no defocus.

RESULTS

Although kinetic sensitivity with the III4e and I4e stimuli decreased slightly at the inferior nasal, total kinetic sensitivity measured with the III4e and I4e stimuli was unaffected by optical defocus. Conversely, kinetic sensitivity measured with the I3e, I2e, and I1e stimuli decreased at defocus greater than +6 D (p < 0.05), + 3 D (p < 0.01), and at a defocus greater than +1 D (p < 0.01), respectively.

CONCLUSIONS

Kinetic sensitivity was unaffected by defocus when measured with III4e and I4e stimuli. However, measurements with I3e, I2e, and I1e stimuli were affected, in particular measurements with I2e and I1e stimuli. Therefore, we conclude that optimal refractive correction with a contact lens or a spectacle lens is required in order to obtain accurate kinetic perimetry results, particularly for lower intensity stimuli.

Blur-resistant perimetric stimuli

PURPOSE

To develop perimetric stimuli that are resistant to the effects of peripheral defocus.

METHODS

One eye each was tested on subjects free of eye disease. Experiment 1 assessed spatial frequency, testing 12 subjects at eccentricities from 2 to 7 degrees using blur levels from 0 to 3 diopters (D) for two (Gabor) stimuli (spatial SD, 0.5 degrees; spatial frequencies, 0.5 and 1.0 cycles per degree [cpd]). Experiment 2 assessed stimulus size, testing 12 subjects at eccentricities from 4 to 7 degrees using blur levels 0 to 6 D for two Gaussians with SD of 0.5 and 0.25 degrees and a 0.5-cpd Gabor with SD of 0.5 degrees. Experiment 3 tested 13 subjects at eccentricities from fixation to 27 degrees using blur levels 0 to 6 D for Gabor stimuli at 56 locations; the spatial frequency ranged from 0.14 to 0.50 cpd with location, and SD was scaled accordingly.

RESULTS

In experiment 1, blur by 3 D caused a small decline in log contrast sensitivity for the 0.5-cpd stimulus (mean ± SE, 0.09 ± 0.08 log units) and a larger (t = 7.7, p < 0.0001) decline for the 1.0-cpd stimulus (0.37 ± 0.13 log units). In experiment 2, blur by 6 D caused minimal decline for the larger Gaussian, by 0.17 ± 0.16 log units, and larger (t > 4.5, p < 0.001) declines for the smaller Gaussian (0.33 ± 0.16 log units) and the Gabor (0.36 ± 0.18 log units). In experiment 3, blur by 6 D caused declines by 0.27 ± 0.05 log units for eccentricities from 0 to 10 degrees, by 0.20 ± 0.04 log units for eccentricities from 10 to 20 degrees, and 0.13 ± 0.03 log units for eccentricities from 20 to 27 degrees.

CONCLUSIONS

Experiments 1 and 2 allowed us to design stimuli for experiment 3 that were resistant to effects of peripheral defocus.

Myopia and glaucoma: diagnostic and therapeutic challenges

PURPOSE OF REVIEW

There is strong epidemiologic evidence linking myopia with glaucomatous disease, but a myopic optic nerve can pose significant challenges with regard to making the correct diagnosis of glaucoma. This review provides an overview of these diagnostic and therapeutic challenges with a particular focus on how the growing prevalence of myopia among specific populations may impact such therapy.

RECENT FINDINGS

For a given individual, the link between myopia and glaucoma remains murky in many circumstances, largely because of the fact that it is difficult to separate out myopia-related structural and functional abnormalities from 'true' glaucomatous changes. Using optical coherence tomography (OCT) imaging, myopia has been found to be associated with temporal displacement and thinning of the superior and inferior nerve fiber layer bundles. In particular, sequential generations of 'Asian' ethnicities have been noted to demonstrate increasing rates of high myopia at earlier ages, sometimes with associated visual field defects at normal intraocular pressures. As is the case with any progressive condition, it is often not possible to distinguish glaucomatous from nonglaucomatous disease based on a single examination, and thus follow-up with OCT or perimetry from an established baseline is useful.

SUMMARY

Although myopia is a known risk factor for glaucoma, it may also result in structural and functional defects that cannot be distinguished from those caused by glaucoma based solely on cross-sectional information. Longitudinal observation may be necessary to distinguish among the multiple effects of myopia on the optic nerve and the natural history of glaucoma, which may vary substantially amongst those who are affected.

Choroidal thickness and visual acuity in highly myopic eyes

PURPOSE

To examine predictive factors for visual acuity in highly myopic eyes.

METHODS

Consecutive patients with high myopia (≥6 diopters [D]) with no other pathology such as lacquer cracks in the fovea, choroidal neovascularization, or myopic macular schisis, were evaluated. The study was performed in 2 retina centers, one in the United States and the other in Japan. Enhanced depth imaging optical coherence tomography was obtained, and the central foveal, outer retinal hyporeflective layer and inner segment to retinal pigment epithelium aggregate, and the subfoveal choroidal thicknesses were measured. Correlations were calculated among the measured variables and visual acuity. Generalized estimating equation models were used to identify predictors of visual acuity.

RESULTS

The New York cohort was composed of 35 eyes of 25 patients who had a mean age of 57 years (standard deviation, ±18.1 years) and a mean refractive error of -10.9 D (±3.6 D). The Japanese cohort was composed of 110 eyes of 61 patients who had a mean age of 46.8 years (±14.7 years) and a mean refractive error of -9.2 D (±3.1 D) and a mean axial length of 27 mm (±1.4 mm). The mean subfoveal choroidal thickness was 113.3 μm (±53.9 μm) in the New York group and 172.9 μm (±72.8 μm) in the Japanese group. In each group, the subfoveal choroidal thickness showed a significant inverse correlation with age and myopic refractive spherical equivalent. The subfoveal choroidal thickness was inversely correlated with logarithm of the minimum angle of resolution visual acuity (P = 0.041, New York group; P = 0.001, Japan group). The only significant predictor in the pooled data for logarithm of the minimum angle of resolution visual acuity was subfoveal choroidal thickness (P ≤ 0.001). Clinic location was not a significant predictor.

CONCLUSION

Choroidal thickness in high myopia is inversely correlated with increasing age and myopic refractive error and is an important predictor of visual acuity. Given that myopia is increasing worldwide, these findings may have epidemiologic significance.

Risk factors for primary open-angle glaucoma in Japanese subjects attending community health screenings

Background/aims

To describe risk factors associated with primary open-angle glaucoma (POAG) in Japanese subjects who participated in community health screenings.

Methods

Residents of Akita, Japan, participating in a community health checkup were selected to undergo a comprehensive ophthalmic examination. Glaucoma was diagnosed based on optic disk appearance, perimetric results, and other ocular findings. Systemic blood pressure and intraocular pressure were measured and ocular perfusion pressure was calculated. Logistic regression analysis was performed to determine risk factors for POAG patients.

Results and conclusion

Of the 710 subjects examined, 26 had POAG. The estimated prevalence of POAG was 3.7%. After adjusting for age, the prevalence of POAG was similar to that found in the Tajimi Study of Japanese subjects. Multivariate logistic regression analysis demonstrated that older age (≥60 years, odds ratio [OR]: 3.49), lower diastolic blood pressure (≤58 mmHg, OR: 2.11), higher intraocular pressure (≥19 mmHg, OR: 4.12), and lower ocular perfusion pressure (≤34 mmHg, OR: 5.78) were associated with increased risk of having POAG. These findings may be relevant for identifying high risk groups.

Long-term development of significant visual field defects in highly myopic eyes

PURPOSE

To identify the characteristics that are associated significantly with visual field (VF) defects in highly myopic eyes.

DESIGN

Retrospective, observational series.

METHODS

The medical records of 492 eyes of 308 patients with high myopia (myopic refractive error > 8 diopters or axial length ≥ 26.5 mm) with a follow-up of 5 years or more were reviewed. The VFs were determined by Goldmann kinetic perimetry, and the VFs were quantified in 100 sectors within the V4 isopter. Eyes with loss of 10% or more of the sectors were classified as having significant VF defects, and a further loss of 10% or more during the follow-up period was classified as a significant progression. To avoid the influence of the posterior fundus changes resulting from the high myopia, eyes with any type of myopic macular or peripheral lesions that could cause visual field defects were excluded.

RESULTS

Significant VF defects were newly developed in 13.2% of these selected highly myopic eyes during a mean follow-up ± standard deviation of 11.6 ± 5.5 years. The incidence of significant VF defects in myopic eyes was significantly higher in eyes with an oval optic disc than that in eyes with a round optic disc. An oval optic disc was present significantly more frequently in the myopic eyes with VF defects. Temporal and nasal VF defects were present in the same eye. Among the eyes with significant VF defect, the temporal VF defects were observed in 61.5% of the eyes with round discs, in 75.0% of the eyes with vertically oval discs, and in 68.2% of the eyes with obliquely oval discs. During a mean follow-up ± standard deviation of 10.2 ± 3.4 years, 73.8% of the eyes showed a significant progression of the VF defects. An abrupt change of the scleral curvature (types VII and IX staphyloma by Curtin) was the only factor significantly associated with a progression of the VF defects.

CONCLUSIONS

Because the VF defects are progressive, we suggest that high myopia is a high risk factor for VF defects and that these eyes be examined at least once yearly. The combination of stretching and distortion of the optic nerve fibers resulting from an abrupt change of scleral curvature may be the factors that lead to the damage of the optic nerve fibers in highly myopic eyes.

Axial length does not correlate with degree of visual field loss in myopic Chinese individuals with glaucomatous appearing optic nerves

PURPOSE

We previously described a group of patients of Chinese ancestry who presented with optic nerve appearance and visual field loss suggestive of glaucoma but did not show progression characteristic of this disease for up to 7 years. The purpose of this study was to assess whether axial length is a risk factor for visual field loss in patients presenting with this cluster of findings.

PATIENTS AND METHODS

Twenty patients of Chinese ancestry with characteristics of this previously described condition including myopia, tilted discs, and glaucomatous visual field abnormalities who also had asymmetric visual field loss were enrolled in this study. Patients underwent axial length measurement of both eyes and a fellow eye analysis was performed to determine the relationship between axial length and visual field loss.

RESULTS

Tilted discs were found in 30 out of 40 eyes, with cup/disc ratios ranging from 0.5 to 0.9. Myopia >6.00 diopters was also found in 30 out of 40 eyes. In these subjects with disease that was discordant between the 2 eyes, longer axial length was not found to be associated with greater visual field loss (P>0.99, Freeman-Halton extension of the Fisher exact test). No correlation was found between axial length and mean deviation on visual field testing (r=-0.06).

CONCLUSIONS

We did not find axial length to be a risk factor for visual field loss in eyes with asymmetric disease in this patient population. These findings suggest that factors other than progressive lengthening of the eye play an important role in the etiology of glaucomatous appearing optic nerve damage and visual field loss in this specific subset of patients.

Tilted optic disks

Tilted optic disks are a common finding in the general population. An expression of anomalous human development, the tilted disk appears rotated and tilted along its axes. Visual sequelae described with tilted optic disks include myopia, astigmatism, visual field loss, deficient color vision, and retinal abnormalities. Although the natural course of tilted optic disks is nonprogressive, the anomaly can be mistaken for tumors of the anterior visual pathway, edema of the optic nerve head, or glaucoma. A thorough examination of patients with tilted disk includes refraction, dilated fundus examination, and visual field testing. At times, neuroimaging may be necessary to arrive at the correct diagnosis. Until normative data are validated for tilted disks, the role of new imaging technologies for the optic nerve head is limited. Familiarity with the spectrum of ophthalmoscopic appearance and the clinical manifestations of tilted disks may be the most critical factors in avoiding misdiagnosis.

Effect of higher order aberrations on contrast sensitivity function in myopic eyes

PURPOSE

To evaluate the relation between higher order aberrations (HOAs) and contrast sensitivity function (CSF) in a population with myopia.

METHODS

In this case series, HOAs were measured in 70 myopic eyes over a 6-mm pupil. Contrast sensitivity was also measured. From the contrast sensitivity data, the area under the log contrast sensitivity function (AULCSF) was calculated. Pupil diameter was measured under photopic conditions.

RESULTS

Seventy right eyes of 70 myopic subjects with a mean age of 26.6 +/- 5.7 years were studied. The mean spherical equivalent and refractive astigmatism were -4.97 +/- 1.6 D and 0.93 +/- 0.5 D, respectively. AULCSF was significantly but negatively correlated with the cycloplegic spherical equivalent (r (2) = 0.57, P = 0.02), the root mean square (RMS) of total HOAs (r (2) = 0.065, P = 0.03), the RMS of fourth-order aberrations (r (2) = 0.089, P = 0.015), and the RMS of the spherical aberration (r (2) = 0.037, P = 0.004). AULCSF did not have any significant association with age, photopic pupil diameter, refractive astigmatism, or the RMS of the coma aberration.

CONCLUSION

Spherical and fourth-order aberrations significantly affect CSF in myopic eyes. However, the effect of myopia on CSF cannot be attributed only to HOAs. Other factors such as neural elements in the visual pathway should be taken into account.

Nonprogressive glaucomatous cupping and visual field abnormalities in young Chinese males

OBJECTIVE

To describe a series of young to middle-aged men of Chinese origin who presented with a constellation of ocular findings suggestive of glaucoma, that were found to be stable over a 7-year period.

DESIGN

Retrospective case series.

PARTICIPANTS

Sixteen 25- to 66-year-old male patients.

METHODS

Medical records of the participants, of Chinese origin and referred for glaucoma evaluation over a 7-year period, were reviewed. All patients underwent complete ophthalmic examinations, stereo imaging of the optic nerves, and automated perimetry. Fewer than 5% of all patients seen in this practice were of Chinese origin. The patients were observed for the duration of the study in a single glaucoma clinic.

MAIN OUTCOME MEASURES

Visual field (VF) changes or progressive optic nerve cupping suggestive of glaucoma.

RESULTS

The patients had an average age of 38.9 years. Tilted discs were present in 75.0% (24/32) and peripapillary atrophy in 81.3% (26/32) of nerves. Cup-to-disc ratios ranged from 0.20 to 0.95 and averaged 0.56. The lowest intraocular pressure (IOP) in any patient at any time was 8 mmHg, whereas the highest was 29 (average range, 13.5-17.9). Intraocular pressure-lowering therapy had been used in 56.3% (9/16). There was a family history of presumed glaucoma in 25.0% (4/16) of patients. High myopia (>-6.00-diopter spherical equivalent [SE]) was present in 43.8% of eyes (14/32), and SEs ranged from -11.25 to +0.25. The most common VF defect was an arcuate defect, found in 31.3% (10/32) of patients. There were no females of Chinese origin with similar findings identified during this period. Neither optic nerve nor significant VF progression was found during the follow-up period, regardless of the use of IOP-lowering therapy.

CONCLUSIONS

These young Chinese patients previously diagnosed with glaucoma or considered glaucoma suspects had stable ocular findings for up to 7 years, irrespective of IOP-lowering therapy. Their condition was associated with myopia and tilted discs. Many were being treated with IOP-lowering therapy for glaucoma, a condition they may not have had. Further prospective epidemiologic study is needed to determine whether such a constellation of nonprogressive findings is more common in young Chinese males than in the general population.

Defining myopia using refractive error and uncorrected logMAR visual acuity >0.3 from 1334 Singapore school children ages 7-9 years

AIM

To determine the association of spherical equivalent (SE) with low uncorrected visual acuity (VA) along with a proposed definition for myopia using logMAR VA >0.3 as the criteria.

METHODS

1334 Chinese schoolchildren (mean age 7.8; range 7-9 years) were enrolled in the study after those who had hyperopia > or =+2.00 dioptres (D) and astigmatism > = -2.00 D were excluded. Uncorrected logMAR VA was measured for both eyes. Cycloplegia autorefraction was achieved by the instillation of three drops of 1% cyclopentolate 5 minutes apart. The average of five successful consecutive refraction and keratometry readings were obtained with calibrated Canon RK5 autokeratorefractometers by well trained optometry students, at least 30 minutes after the instillation of the third drop of cyclopentolate. SE cut-off points (-0.25 D, -0.5D, -0.75 D, -1.0 D) were evaluated.

RESULTS

Using different SE cut-off points, the myopia prevalence rates of this sample of schoolchildren varied from 45.8% (SE at least -0.25 D) to 30.7% (SE at least -1.0 D). The cut-off point of > or =-0.75 D had a sensitivity and specificity of 91.8% (95% CI, 89.2 to 94.4) and 93.7% (95% CI, 92.1 to 95.3), respectively, to predict low vision defined as uncorrected logMAR VA > 0.3 (either eye). The next best cut-off point of -0.5D had a higher sensitivity (93.3%), but lower specificity (87.9%).

CONCLUSIONS

The cut-off points of -0.75D and -0.5D in SE refraction are appropriate for the prediction of uncorrected logMAR VA worse than 0.3, which is the criterion for the US common state adult driver licensing standard.

Predictive Value of Frequency Doubling Technology Perimetry for Detecting Glaucoma in a Developing Country

PURPOSE

To determine the feasibility and diagnostic precision of Frequency Doubling Technology (FDT) perimetry as a method to detect glaucoma in rural villages of a developing country.

DESIGN

Cross-sectional study.

METHODS

Testing included FDT perimetry (C-20-5 screening protocol), tonometry, anterior segment biomicroscopy, and dilated ophthalmoscopy in 296 rural, non-English speaking residents of Southern India over 35 years old. Participants repeated the FDT if they had a location with reduced sensitivity or an unreliable result. We defined an abnormal FDT as one location of reduced sensitivity present on both the initial and repeat examination. We determined the diagnostic precision of FDT separately for a glaucomatous optic disc, a cup to disc ratio (C/D) > or = 0.7, and a C/D > or = 0.8.

RESULTS

Ninety-three percent of subjects were able to complete the test satisfactorily. With repeat FDT testing, 37% of eyes with abnormal FDT results subsequently converted to normal and 67% of eyes with unreliable results subsequently became reliable. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for a glaucomatous optic disc were 7%, 87%, 13%, 76%, and 69%, respectively; for a C/D > or = 0.7, they were 0%, 87%, 0%, 91%, and 81%, respectively; and for a C/D > or = 0.8, they were 0%, 87%, 0%, 99%, and 87%, respectively.

CONCLUSION

Clinicians can use FDT perimetry to rapidly screen for glaucoma in rural villages of a developing country. FDT testing had high specificity and negative predictive value, but low sensitivity and positive predictive value. The low sensitivity suggests that FDT has limited applicability as the sole test for glaucoma screening in this population. Repeat testing of FDT results that are unreliable or suspected of being abnormal is beneficial for this screening procedure.

Optic disk ovality as an index of tilt and its relationship to myopia and perimetry

PURPOSE

To examine the association of optic disk ovality with myopic refractive error, axial length, and the visual field.

DESIGN

Prospective observational case series.

METHODS

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 < or = 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.

RESULTS

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).

CONCLUSIONS

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.

Traitement actuel des glaucomes aigus par fermeture de l’angle

Treatment of acute angle-closure glaucoma is now better adapted for each stage of the disease. The urgent necessity to lower intraocular pressure is normally achieved using medical therapy followed by laser peripheral iridotomy and sometimes by filtration surgery. Early argon laser peripheral iridoplasty is effective and safe in some cases, allowing a very early peripheral iridotomy to be performed and avoiding systemic treatment. When surgery is required, lens extraction must be considered. In all cases, IOP control and regular gonioscopic examination the 1st Year are essential to detect peripheral anterior synechiae.

Refractive errors, intraocular pressure, and glaucoma in a white population

OBJECTIVE

To examine the relation of refractive errors to glaucoma and intraocular pressure (IOP) in a defined white population.

DESIGN

Population-based cross-sectional and follow-up study.

PARTICIPANTS

Persons aged 43 to 86 years living in Beaver Dam, Wisconsin (n = 4926).

METHODS

All participants received a standardized assessment of refraction, IOP, and glaucoma at baseline (1988-1990), with IOP remeasured 5 years later (1993-1995). Refraction was defined at baseline as follows: myopia as spherical equivalent of -1.00 diopters (D) or less, emmetropia as -0.75 to +0.75 D, and hyperopia as +1.00 D or more.

MAIN OUTCOME MEASURES

Relation of baseline refraction to prevalent glaucoma (defined from IOP, optic disc, and visual field criteria) and incident ocular hypertension (defined as IOP more than 21 mmHg at the 5-year examination in eyes with IOP of 21 mmHg or less at baseline).

RESULTS

A myopic refraction was correlated with increasing IOP at baseline (P < 0.001). After controlling for age and gender, persons with myopia were 60% more likely to have prevalent glaucoma than those with emmetropia (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1, 2.3). In contrast, controlling for age, gender, and baseline IOP, persons with hyperopia were 40% more likely to have incident ocular hypertension than those who were emmetropic at baseline (OR, 1.4; 95% CI, 1.0, 2.0). Myopia was not related to incident ocular hypertension.

CONCLUSIONS

In these population-based data, there was a cross-sectional association of myopia with higher IOP and prevalent glaucoma. Similar associations have been found in previous studies. Hyperopia may be associated with 5-year risk of ocular hypertension, a finding that needs further investigation.