Age-related decline of disc rim area in visually normal subjects

Snail Track Lesion with Flat Keratometry in Anterior Segment Dysgenesis Caused by a Novel FOXC1 Variant

We report the phenotype of a 15-year-old female patient with anterior segment dysgenesis (ASD) caused by a novel heterozygous loss-of-function FOXC1 variant. The proband underwent an ophthalmic examination as well as a molecular genetic investigation comprising exome sequencing, a single nucleotide polymorphism array to access copy number and Sanger sequencing to exclude non-coding causal variants. There was bilateral mild iris hypoplasia with pupil deformation and iridocorneal adhesions. In addition to these features of ASD, the corneas were flat, with mean keratometry readings of 38.8 diopters in the right eye and 39.5 diopters in the left eye. There was a snail track lesion of the left cornea at the level of the Descemet membrane. The central corneal endothelial cell density was reduced bilaterally at 1964 and 1373 cells/mm² in the right and left eyes, respectively. Molecular genetic analysis revealed that the proband was a carrier of a novel heterozygous frameshifting variant in FOXC1, c.605del p.(Pro202Argfs*113). Neither parent had this change, suggesting a de novo origin which was supported by paternity testing. We found no possibly pathogenic variants in the other genes associated with posterior corneal dystrophies or ASD. Further studies are warranted to verify whether there is a true association between snail track lesions, corneal flattening, and pathogenic variants in FOXC1.

Accuracy of the ISNT rule and its variants for differentiating glaucomatous from normal eyes in a population-based study

AIMS

To evaluate the accuracy of the ISNT rule (I=inferior, S=superior, N=nasal, T=temporal) and its variants with neuroretinal rim width and retinal nerve fibre layer (RNFL) thickness measurements differentiating normal from glaucomatous eyes.

METHODS

The diagnosis accuracy of the ISNT rule and its variants was evaluated in a population-based study. Neuroretinal rim widths were measured on monoscopic optic disc photographs with an image-processing program. RNFL thickness measurements were obtained with spectral-domain optical coherence tomography (SD-OCT).

RESULTS

In this study including 940 normal subjects and 93 patients with glaucoma, the sensitivity of the ISNT rule with optic disc photographs was 94.1% (95% CI 90.2 to 98.1), whereas its specificity was 49.2% (46.9 to 51.6). When using the IST rule, the sensitivity decreased to 69.9% (62.1 to 77.6) with a higher specificity, 87.0% (85.3 to 88.6). All the diagnosis indicators were somewhat lower for the different rules using RNFL thickness: the sensitivity of the ISNT rule was 79.4% (72.6 to 86.2) and its specificity was 34.1% (31.9 to 36.4). With the IST rule, the sensitivity decreased to 50.0% (41.6 to 58.4) while the specificity increased to 64.9% (62.7 to 67.2).

CONCLUSIONS

The ISNT and IST rules applied to neuroretinal rim width measurement by optic disc photographs are useful and simple tools for differentiating normal from glaucomatous eyes. The translation of these rules to RNFL thickness by SD-OCT is of limited value.

Peripapillary microcirculation in Leber hereditary optic neuropathy

PURPOSE

In this prospective observational comparative case series, we aimed to study the peripapillary capillary network with spectral-domain optical coherence tomography angiography (OCT-A) in Leber hereditary optic neuropathy (LHON).

METHODS

Twelve eyes of six individuals, of these three males (five eyes) after clinical onset of visual impairment were imaged by OCT-A with scans centred on optic discs. Control group consisted of 6 eyes with no visual impairment.

RESULTS

The three affected individuals lost vision 6 years (at age 22 years), 2 years and 3 months (at age 26 years) and 1 year and 2 months (at age 30 years) prior to OCT-A examination. All five affected eyes had alterations in density of the radial peripapillary microvascular network at the level of retinal nerve fibre layer, including an eye of a patient treated with idebenone that underwent almost full recovery (best corrected visual acuity 0.87). Interestingly, the other eye showed normal ocular findings 14 months after onset. Results of OCT-A examination in this eye were unfortunately inconclusive due to a delineation error. At the level of the ganglion cell layer differences could be also noted, but only in two severely affected individuals. There were no differences between unaffected mutation carriers and control eyes.

CONCLUSION

Optical coherence tomography angiography scans confirmed that the peripapillary microvascular network is highly abnormal in eyes manifesting visual impairment due to LHON. These findings support the hypothesis that microangiopathy contributes to the development of vision loss in this mitochondrial disorder.

Optic Disc Measurements with the 78 Diopter Lens, Zeiss 4-Mirror Contact Lens and Computerized Image Analysing System

We evaluated the 78 diopter (D) lens and Zeiss 4-mirror lens for the measurement of vertical and horizontal optic disc diameters during slit-lamp biomicroscopy and compared the results with the measurements made with the computerized image analysing system (IMAGEnet 640, Topcon, Japan) in 30 eyes of 30 patients. The 78D lens and Zeiss 4-mirror lens measurements both correlated well with the computerized image analysis measurements (r=0.881 for vertical and r=0.895 for horizontal disc diameter measurements with the 78D lens and r=0.883 for vertical and r=0.891 for horizontal disc diameter measurements with the Zeiss 4-mirror lens). The 78D lens measurements overestimated vertical disc diameter by 5.3% and horizontal disc diameter by 4.4%. The Zeiss 4-mirror lens underestimated the vertical disc diameter by 2.4% and horizontal disc diameter by 2.2%. Thus either lens can be used for a quick estimation of the optic disc size, since the results correlate well with the computerized image analysis measurements.

Bruch's Membrane Opening Minimum Rim Width and Retinal Nerve Fiber Layer Thickness in a Normal White Population: A Multicenter Study

PURPOSE

Conventional optic disc margin-based neuroretinal rim measurements lack a solid anatomic and geometrical basis. An optical coherence tomography (OCT) index, Bruch's membrane opening minimum rim width (BMO-MRW), addresses these deficiencies and has higher diagnostic accuracy for glaucoma. We characterized BMO-MRW and peripapillary retinal nerve fiber layer thickness (RNFLT) in a normal population.

DESIGN

Multicenter cross-sectional study.

PARTICIPANTS

Normal white subjects.

METHODS

An approximately equal number of subjects in each decade group (20-90 years of age) was enrolled in 5 centers. Subjects had normal ocular and visual field examination results. We obtained OCT images of the optic nerve head (24 radial scans) and peripapillary retina (1 circular scan). The angle between the fovea and BMO center (FoBMO angle), relative to the horizontal axis of the image frame, was first determined and all scans were acquired and analyzed relative to this eye-specific FoBMO axis. Variation in BMO-MRW and RNFLT was analyzed with respect to age, sector, and BMO shape.

MAIN OUTCOME MEASURES

Age-related decline and between-subject variability in BMO-MRW and RNFLT.

RESULTS

There were 246 eyes of 246 subjects with a median age of 52.9 years (range, 19.8-87.3 years). The median FoBMO angle was -6.7° (range, 2.5° to -17.5°). The BMO was predominantly vertically oval with a median area of 1.74 mm(2) (range, 1.05-3.40 mm(2)). Neither FoBMO angle nor BMO area was associated with age or axial length. Both global mean BMO-MRW and RNFLT declined with age at a rate of -1.34 μm/year and -0.21 μm/year, equivalent to 4.0% and 2.1% loss per decade of life, respectively. Sectorially, the most rapid decrease occurred inferiorly and the least temporally; however, the age association was always stronger with BMO-MRW than with RNFLT. There was a modest relationship between mean global BMO-MRW and RNFLT (r = 0.35), whereas sectorially the relationship ranged from moderate (r = 0.45, inferotemporal) to nonexistent (r = 0.01, temporal).

CONCLUSIONS

There was significant age-related loss of BMO-MRW in healthy subjects and notable differences between BMO-MRW and RNFLT in their relationship with age and between each other. Adjusting BMO-MRW and RNFLT for age and sector is important in ensuring optimal diagnostics for glaucoma.

Glaucomatous progression in series of stereoscopic photographs and Heidelberg retina tomograph images

OBJECTIVE

To compare optic disc changes using automated analysis of Heidelberg retina tomograph (HRT) images with assessments, by glaucoma specialists, of change in stereoscopic photographs.

METHODS

Baseline and follow-up stereophotographs and corresponding HRT I series of 91 eyes from 56 patients were selected. The selection criteria were sufficiently long, good-quality HRT series (7 visits in > or =70 months of follow-up) and follow-up photographs contemporaneous with the final HRT image. Topographic change analysis (TCA), statistic image mapping (SIM), and linear regression of rim area (RALR) across time were applied to HRT series. Glaucomatous change determined from stereophotographs by expert observers was used as the reference standard.

RESULTS

Expert observers identified 33 eyes (36%) as exhibiting glaucomatous change. Altering HRT progression criteria such that 36% of eyes progressed according to each method resulted in concordance between HRT methods and stereophotograph assessment of 54% for TCA, 65% for SIM, and 67% for RALR (Cohen kappa = 0.05, 0.23, and 0.30, respectively). Receiver operating characteristic curves of the HRT analyses revealed poor precision of HRT analyses to predict stereophotograph-assessed change: areas under the curve were 0.61 for TCA, 0.62 for SIM, and 0.66 for RALR.

CONCLUSIONS

Statistical methods for detecting structural changes in HRT images exhibit only moderate agreement with each other and have poor agreement with expert-assessed change in optic disc stereophotographs.

Optic nerve heads in pediatric African Americans using retinal tomography

PURPOSE

To characterize optic nerve head (ONH) parameters including symmetry between the eyes in healthy African American children using the Heidelberg retinal tomograph II, and to determine if there are associations between these parameters and age, refractive error, or gender.

METHODS

The ONHs of 146 African American children aged 6 to 17 years without ocular disease were imaged with the Heidelberg retinal tomograph II. Mean values for 11 ONH parameters were determined as was their relationship to age, gender, and refractive error. Interocular symmetry of the parameters was determined.

RESULTS

The mean (+/-standard deviation) disc area, rim area, and cup area were 2.18 +/- 0.57 mm2, 1.63 +/- 0.40 mm2, and 0.52 +/- 0.37 mm2, respectively. The mean linear cup-to-disc (C/D) ratio was 0.45 +/- 0.15, and mean cup depth was 0.22 +/- 0.10 mm. The mean retinal nerve fiber layer thickness was 0.26 +/- 0.07 mm. The ONH parameters were not related to age or refractive error. With the exception of the C/D area ratio and linear C/D ratio, which were greater in boys than in girls, ONH parameters were not related to gender. Most parameters were strongly correlated between the right and left eyes. The average interocular differences in disc area, cup area, rim area, linear C/D ratio, and mean retinal nerve fiber layer thickness were 0.09 +/- 0.31 mm2, 0.04 +/- 0.22 mm2, 0.06 +/- 0.40 mm2, 0.02 +/- 0.11, and 0.00 +/- 0.06 mm2, respectively.

CONCLUSIONS

ONH parameters were not related to age and refractive error, and only C/D area ratio and linear C/D ratio were greater in boys than girls in a clinical sample of African American children. These measures of normative ONH parameters and range of interocular differences may be helpful in clinical pediatric eye care to facilitate identification of African American children with abnormal optic discs.

Rates of neuroretinal rim and peripapillary atrophy area change: a comparative study of glaucoma patients and normal controls

OBJECTIVE

To compare the rates of global and sectoral neuroretinal rim area (NRA) and peripapillary atrophy area (PPAA) change in open-angle glaucoma patients and normal control subjects and to determine the relationship between rates of NRA and PPAA change.

DESIGN

Prospective, longitudinal cohort study of cases and controls.

PARTICIPANTS AND CONTROLS

Ninety-four patients with open-angle glaucoma and 54 control subjects.

METHODS

Patients and controls were imaged with confocal scanning laser tomography every 6 months. The NRA and PPAA in 1 eye were analyzed to determine the rate of change globally and in 12 30 degrees sectors by regression analysis. Rates of global NRA and PPAA change were correlated. Sectors were ranked from 1 to 12 each according to the magnitude of NRA and PPAA change and were compared between patients and controls using rank-order correlation. Spatial concordance between rates of NRA and PPAA change was calculated as sector rank distance between correspondingly ranked sectors.

MAIN OUTCOME MEASURES

Rates of global and sectoral NRA and PPAA change.

RESULTS

The mean (+/-standard deviation) follow-up was 8.6+/-2.9 years for patients and 7.1+/-3.6 years for controls. Globally, NRA declined more rapidly in patients compared with controls, expressed either in absolute units (medians, -5.33x10(-3) mm(2)/year and -1.25x10(-3) mm(2)/year, respectively; P = 0.006) or percentage of baseline NRA (medians, -0.42%/year and -0.07%/year, respectively; P = 0.001). The global rate of PPAA change was not significantly higher in patients compared with controls (12.66x10(-3) mm(2)/year and 9.43x10(-3) mm(2)/year, respectively; P = 0.173). Rates of global and sectoral NRA and PPAA change were correlated poorly in either group. There was a high correlation between ranked sectors of NRA change in patients and controls (P</=0.001), indicating similar patterns of NRA decline in patients and controls; however, this was not the case for rates of PPAA change.

CONCLUSIONS

These findings indicate an age-related regional susceptibility of the optic disc that may be accelerated in glaucoma. The poor relationship between rates of NRA and PPAA change suggests their temporal dynamics are uncoupled.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Laser scanning tomography of optic discs of the normal Japanese population in a population-based setting

OBJECTIVE

To evaluate the optic disc characteristics using the Heidelberg retina tomograph (HRT) II in a large sample of normal Japanese subjects.

DESIGN

Cross-sectional study.

PARTICIPANTS

A total of 3576 eyes of 2036 normal subjects, with good-quality HRT II images, of 6042 eyes of 3021 subjects aged 40 years or more who participated in the Tajimi Study, a population-based eye study in Japan.

METHODS

Optic disc parameters were obtained using HRT II, and the association of gender, age, height, weight, blood pressure, ocular perfusion pressure, refraction, intraocular pressure (IOP), central corneal thickness (CCT), and disc size on HRT parameters was assessed using simple and multiple regression analyses.

MAIN OUTCOME MEASURES

HRT parameters, including disc area, cup area, rim area, cup-to-disc area ratio, cup volume, rim volume, mean cup depth, maximum cup depth, height variation contour, cup shape measure, mean retinal nerve fiber layer (RNFL) thickness, and RNFL cross-sectional area, and the crude and partial correlations of the potential confounders with the HRT parameters.

RESULTS

Disc area, cup-to-disc area ratio, and rim area averaged 2.06+/-0.41 mm(2) (mean+/-standard deviation), 0.23+/-0.13, and 1.55+/-0.29 mm(2), respectively. All HRT parameters were strongly or moderately correlated between right and left eyes (Pearson's correlation coefficients = 0.45-0.83, P<0.001). Absolute inter-eye differences in several HRT parameters were positively correlated with disc area (P<0.05). Multiple regression analyses adjusting for the confounders showed weak but significant correlations of height, refractive error, IOP, and CCT with several HRT parameters (partial correlation coefficient (absolute value) = 0.04-0.16, P<0.05), and moderate or weak but significant correlations of disc area with all HRT parameters (partial correlation coefficient [absolute value] = 0.05-0.73, P<0.05). Gender, weight, blood pressure, and ocular perfusion pressure did not significantly correlate with HRT parameters.

CONCLUSIONS

This report presents reference data of normality for the HRT parameters based on a large sample of normal Japanese subjects. There were small but significant influences of height, refractive error, IOP, and CCT on several HRT parameters. Many HRT parameters were moderately or weakly affected by disc size.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Quantification of neuroretinal rim loss using digital planimetry in long-term follow-up of normals and patients with ocular hypertension

PURPOSE

The purpose of this study was to investigate if digital planimetry is appropriate for quantification of neuroretinal rim loss in patients with ocular hypertension (OHT) and if there is an age-related neuroretinal rim loss in normals.

PATIENTS AND METHODS

Fifty-six patients with OHT without optic disc change, 13 patients with OHT and conversion to early glaucoma during follow-up and 42 age-matched controls were recruited from the Erlangen Glaucoma Registry. Annually, all patients underwent complete ophthalmologic examination including detailed diagnostic testing concerning glaucoma. Gold standard for morphologic evaluation of the optic nerve head was the semiquantitative 2-dimensional-method described by Jonas. Optic disc images from baseline and after 5 or 10 years follow-up were used for digital planimetry. Optic disc area and cup area were measured using commercial software: Soft Imaging System analysis. The investigator was masked for diagnosis and time point of examination.

RESULTS

Mean neuroretinal rim loss was 0.36% per year in controls, 0.54% per year in patients with OHT without progressive disease, and 0.95% per year in OHT and conversion.

CONCLUSIONS

Neuroretinal rim loss was highest in the group of OHT with conversion to early glaucoma during follow-up. In the control group we detected a very low mean neuroretinal rim loss during 10-year follow-up. In ocular hypertensive patients without progressive disease mean neuroretinal rim loss was approximately twice compared with normals.

Evaluating the optic disc and retinal nerve fiber layer in glaucoma. I: Clinical examination and photographic methods

Glaucoma is a leading cause of blindness worldwide and is characterized in part by specific changes in the optic disc and retinal nerve fiber layer. Currently, subjective clinical examination and fundus photography are the most common ways of detecting structural change in glaucoma and monitoring its progression. In the first part of this two-part article, the authors overview structural changes of the optic disc and retinal nerve fiber layer in glaucoma and describe and evaluate photographic methods for observing these changes. In the second part of this article (this issue), recent developments in computer-based optical imaging techniques that allow objective evaluation of the optic disc and retinal nerve fiber layer are described.

Axial length and optic disc size in normal eyes

AIM

To investigate the relationship between optic disc area and axial length in normal eyes of white and black people.

METHODS

Consecutive eligible normal subjects were enrolled. Ocular biometry was obtained using A-scan ultrasonography, and reliable images of the optic disc were obtained using a confocal scanning laser ophthalmoscope. The relationship between optic disc area and axial length was assessed using univariate and multivariate models.

RESULTS

281 eyes of 281 subjects were enrolled. Black subjects (n = 157) had significantly larger discs (mean (SD) disc area, 2.12 (0.5) mm(2)) than white subjects (n = 124; 1.97 (0.6) mm(2); t test, p = 0.02). Optic disc area increased with axial length (Pearson's correlation coefficient, r = 0.13, p<0.035) for the entire study population. Multivariate regression models including race, disc area and axial length showed that a significant but weak linear relationship exists between axial length and disc area (partial correlation coefficient 0.14; p<0.024), and with race and disc area (partial correlation coefficient 0.19; p<0.017) when adjusted for the effects of other terms in the model.

CONCLUSION

Increased disc area is associated with longer axial length measurements and African ancestry. This may have implications for pathophysiology and risk assessment of glaucoma.

Topographic characteristics of the optic nerve head measured with scanning laser tomography in normal Japanese subjects

PURPOSE

Few studies have been performed regarding the topographic information obtained with the Heidelberg retina tomograph (HRT) in normal Japanese. In this study, we examined the factors influencing optic disc parameters and hemisphere symmetry obtained with the HRT in normal Japanese subjects.

METHODS

Mean values and the standard deviation range for the main HRT parameters were evaluated in 223 eyes of 223 normal Japanese subjects. The influence of age, sex, and disc size on HRT topographic data was analyzed. The superior and inferior hemisphere topographic parameters were compared.

RESULTS

Disc area showed a significant difference by sex (P = 0.0493). Rim volume (r = -0.208, P = 0.019), height variation contour (r = -0.275, P = 0.001), and mean retinal nerve fiber layer (RNFL) thickness (r = -0.366, P = 0.001) declined with age. All parameters except height variation contour and mean RNFL thickness showed a clinically significant correlation with disc size (-0.159 < r < 0.719, P < 0.01). Cup parameters in the superior hemisphere were significantly greater than those in the inferior hemisphere. In contrast, rim parameters in the superior hemisphere were significantly smaller than those in the inferior hemisphere.

CONCLUSIONS

Some factors, namely, sex, age, and disc size, affected the optic disc parameters in the HRT measurements. Possible parameter asymmetry between the two hemispheres should be considered in normal eyes.

Visual function in young adults following intrauterine growth retardation

BACKGROUND

Intrauterine growth retardation (IUGR) resulting in infants born small for gestational age is a known risk factor for neurologic deficits and may predispose to poor cognitive development later in life. We recently found an association between IUGR and a reduced neuroretinal rim area at 18 years of age. We evaluated the possible association between IUGR and visual function.

SUBJECTS AND METHODS

We studied 26 subjects who had been born small for gestational age and 20 subjects whose birth weights were appropriate for gestational age (controls) using letter acuity thresholds, color vision testing, full-threshold frequency doubling technology perimetry, and rarebit perimetry at 18 years of age. gestational age had a rarebit hit rate below the normal range as compared with none of the controls (P = .006). These 8 subjects had a significantly smaller rim-disc ratio compared with the subjects who were small for gestational age who had a normal rarebit hit rate (P = .047). The frequency doubling technology indices did not differ significantly between the control group and the group that was small for gestational age, nor did the visual acuity, refraction, and color vision test results.

CONCLUSION

These data indicate that IUGR is associated with an increased rate of impaired visual function, which can be detected by using rarebit perimetry but not frequency doubling technology perimetry, visual acuity, or color vision tests.

Major determinants of optic nerve head topographic characteristics in a normal Turkish population

AIM

To determine the factors affecting the topographic characteristics of the optic nerve head in a normal Turkish population.

METHODS

A cross-sectional study was performed on the optic nerve head of the right eyes of 613 healthy subjects of both sexes aged 11-77 years using a confocal scanning laser ophthalmoscope. The study population was divided into three groups (<20 years, 20-50 years, and>50 years) to evaluate age-related changes in the optic nerve head topography. A total of 15 variables were determined. Statistical analysis was performed using Student's t-test, anova, Tukey HSD test, linear regression analysis and Pearson's correlation coefficient.

RESULTS

Four eyes were excluded from the study due to poor image quality. There were 307 female subjects and 302 male subjects. The mean age of the subjects was 42.1 +/- 15.1 years. The mean optic disc areas were 1.99 +/- 0.45 mm2 and 1.97 +/- 0.41 mm2 for male and female subjects, respectively. The disc area of the subjects ranged between 1.01 and 4.19 mm2. Disc area was found to be associated with all of the optic nerve head variables studied, and was also found to be significantly increased with advancing age (P < 0.05). The only variable that showed a sex-related difference was neuroretinal rim volume, which was found to be higher in female subjects in all cases.

CONCLUSION

Optic disc area was found to be the main determinant of the optic nerve head topography in a normal population. Optic disc area was found to be significantly increased with ageing in a normal population. These acquired changes to the optic disc could suggest stretching of the scleral ring, which may highlight the role of advancing age on the pathogenesis of glaucomatous optic neuropathy.

The normal optic nerve head

BACKGROUND

The normal optic nerve head varies from one person to another, and there is often intraindividual variation as well. Factors such as race and age play an important role in distinguishing what may be considered normal variations in optic nerve head appearance.

METHODS

A literature search and review of the latest studies on the optic nerve head was conducted.

RESULTS

Results of recent studies showed that variations in the average cup-to-disc ratio exist for different races, and with age there is a gradual loss of nerve fibers leading to an overall increase in the cup-to-disc ratio. There is also evidence that congenitally larger optic nerves have larger cup-to-disc ratios and more nerve fibers. Smaller optic nerves, in contrast, have smaller cup-to-disc ratios and fewer nerve fibers. These findings are presented along with sample photographs depicting the normal variations in optic nerve head appearance.

CONCLUSION

Over the past 30 years, technology has allowed for changing views about what may be considered normal in reference to the optic nerve head. This information is valuable to the eye care practitioner in helping to make appropriate patient care management decisions.

Effect of aging on optic nerve appearance: a longitudinal study

AIM

To determine whether aging causes detectable changes in the appearance of the optic disc.

METHODS

A retrospective longitudinal study was performed with quantitative and qualitative evaluations of digitised stereoscopic optic disc photographs of 224 eyes of 224 subjects. There were three groups: 100 normal subjects from the Framingham Eye Study, 68 glaucomatous patients followed longitudinally, and 56 normal subjects and glaucoma patients who had separate sets of disc photos taken on the same day. A disc was considered qualitatively worse if two of three experienced observers agreed that it was worse. Quantitative progression was defined as a >10% decrease in rim/disc area ratio measured with computer assisted planimetry.

RESULTS

With quantitative evaluation, normal eyes (mean follow up 13 years) and same day eyes displayed no statistically significant difference in change of rim/disc area ratios (p=0.095), nor in the number of discs that progressed-five of 100 (5%) v two of 56 (4%) respectively. Glaucomatous eyes (mean follow up 9 years) showed a quantitative loss of disc rim in 24 of 68 (35%), and differed significantly from the normal eyes both in the change of rim/disc area ratio (p<0.0005) and number of discs that progressed (p<0.0005). With qualitative evaluation, the number of progressive discs in the glaucomatous eyes (31%) differed significantly (p<0. 0005) from the normal eyes (3%) and the same day eyes (0%).

CONCLUSIONS

Over a period of follow up appropriate for long term outcome studies in glaucoma, there was no quantitatively or qualitatively detectable neuroretinal rim loss in normal aging optic nerves with stereoscopic optic disc photographs.

Effect of optic disc size or age on evaluation of optic disc variables

AIMS/BACKGROUND

It has been reported that the number of optic nerve fibres decrease with age, and the cup/disc (C/D) ratio increases as the optic disc size increases. Consequently, the normal value of the optic disc variables measured by an optic disc analyser may change according to the optic disc size or age. The effect of individual variations in optic disc size or age on interpretation of optic disc variables was investigated.

METHODS

Topographic optic disc variables of 104 normal Asian adults of both sexes aged 40 to 68 were measured using a confocal scanning laser ophthalmoscope (TopSS, Laser Diagnostic Technologies, Inc). Fourteen variables were evaluated according to the optic disc size or age. Statistical analysis was done by regression analysis.

RESULTS

With an increase in optic disc size, the increase in cup shape, effective area, 1/2 depth area, C/D ratio, neuroretinal rim area, volume above, volume below, and 1/2 depth volume were statistically significant (p < 0.05). However, contour variation, mean contour depth, average depth, maximum depth, average slope, and maximum slope were not affected (p > 0.1). Age did not have any significant influence on optic disc variables (p > 0.1).

CONCLUSION

Optic disc size, but not age, should be considered in the interpretation of optic disc variables.

Aging changes of the optic nerve head in relation to open angle glaucoma

AIMS

To determine the age related changes in optic nerve head structure in a group of normal subjects and assess the significance of any changes in relation to those found in open angle glaucoma.

METHODS

A group of 88 white volunteers and friends and spouses of patients with a normal visual field and normal intraocular pressure was studied. Two different imaging and measurement devices were used (computer assisted planimetry and scanning laser ophthalmoscopy), and the results from each were compared. Measurements were made of the optic disc, optic cup, and neuroretinal rim areas, and the vertical optic disc diameter and cup/disc diameter ratio.

RESULTS

Neuroretinal rim area declined at the rate of between 0.28% and 0.39% per year. Vertical optic cup diameter and optic cup area increased with age. The mean cup/disc diameter ratio increased by about 0.1 between the ages of 30 and 70 years.

CONCLUSIONS

Age related changes are significant and measurable, and should be taken into account when assessing the glaucoma suspect, and when estimating the rate of progression of glaucomatous optic neuropathy in patients with established disease.

Women and men--same eyes?

In ophthalmology, few studies have been designed to investigate possible differences between women and men in a consistent manner. Some evidence is, however, available showing significance male-female differences. The importance of gender in ophthalmological research is emphasized by focusing on some knowledge about sex differences in ocular components in relation to cataract surgery and on the influence of the female hormones on the cornea.

Retinal nerve fiber layer thickness in normal human eyes

PURPOSE

To measure the histologic thickness of the retinal nerve fiber layer (RNFL) in normal human eyes.

METHODS

Human eyes were obtained at autopsy within 6 hours postmortem. The retina was dissected into four quadrants and serially sectioned in historesin. The RNFL thickness was measured histologically in all four quadrants at the disc margin and at regular intervals from the disc margin. Measurements of the RNFL thickness also were obtained at the fovea and in the retinal periphery.

RESULTS

Ten eyes of ten white individuals were studied. Age (mean +/- standard deviation) was 53.1 +/- 19.6 years (range, 18-76 years). For the eyes studied, the disc area (mean +/- standard deviation) and cup:disc ratio (mean +/- standard deviation) were 1.92 +/- 0.1 mm2 and 0.3 +/- 0.08, respectively. Mean superior, inferior, nasal, and temporal RNFL thickness at the disc margin was 405, 376, 372, and 316 microns, respectively. In all four quadrants, the RNFL thickness decreased with increasing distance from the disc margin. The average superior and inferior RNFL thickness was inversely related to age (P = 0.033, P = 0.097, respectively). The average RNFL thickness was not related to disc area. The average RNFL thickness just superior, inferior, nasal, and temporal to the foveola was 27, 34, 26, and 12 microns, respectively. The average RNFL thickness just posterior to the ora serrata in the superior, inferior, nasal, and temporal retinal periphery was 8 to 11 microns.

CONCLUSION

The peripapillary RNFL thickness in humans is thicker than that seen in nonhuman primates. The thinnest peripapillary RNFL is in the region of the papillomacular bundle. These data can be used to determine the accuracy of NFL analyzers in obtaining in vivo RNFL thickness measurements.

Comparative optic disc analysis in normal pressure glaucoma, primary open-angle glaucoma, and ocular hypertension

PURPOSE

The authors wished to determine whether characteristics of optic disc and parapapillary atrophy differ between eyes with ocular hypertension, primary open-angle glaucoma (POAG) and those with normal-pressure glaucoma, including a subset of patients with normal-pressure glaucoma with evidence of serum abnormalities of humoral autoimmunity.

METHODS

Three hundred ninety-two eyes of 196 patients with ocular hypertension, 394 eyes of 197 patients with POAG, and 135 eyes of 68 patients with normal-pressure glaucoma were analyzed. Nerve fiber layer hemorrhage in the optic disc region, retinal arteriolar narrowing, and morphometric parameters of optic disc and parapapillary atrophy were investigated in these groups. Parapapillary atrophy was differentiated in two different zones (alpha and beta).

RESULTS

Nerve fiber layer hemorrhage and arteriolar narrowing were found more frequently in patients with normal-pressure glaucoma than in patients with POAG (P = 0.014, P = 0.004) and ocular hypertension (P < 0.0001, P < 0.0001). Zone beta was detected more often in patients with normal-pressure glaucoma than in those with ocular hypertension (P < 0.001) and POAG (P = 0.013). Although patients with normal-pressure glaucoma had more advanced neural rim loss and larger parapapillary atrophy, there were similar correlations between neural rim area and the area and extension of parapapillary atrophy in patients with normal-pressure glaucoma and POAG. Parapapillary atrophy parameters also were similar in different stages of neural rim damage in patients with normal-pressure glaucoma and POAG (P > 0.05). Optic disc characteristics were not different (P > 0.05) between the subgroups of patients with normal-pressure glaucoma.

CONCLUSION

The authors' findings support the idea that besides the enlargement of the area and extension of parapapillary atrophy that accompanies neural damage in glaucoma, the severity of the parapapillary atrophy also increases as assessed by the increase in zone beta in more damaged eyes. Furthermore, the final clinical appearance of optic nerve damage is similar among patients with POAG, normal-pressure glaucoma, and the subgroups of normal-pressure glaucoma, regardless of their possibly different mechanisms of neuropathy.

The cumulative normalised rim/disc area ratio curve

BACKGROUND

The assessment of the cup of the optic disc depends, among other criteria, on the disc area. A small cup in a small optic disc can indicate an advanced glaucomatous lesion, while on the other hand a large cup in a large optic disc can be normal. Therefore, a cumulative normalised rim/disc area ratio curve could help to distinguish between glaucomatous and normal optic cups. The aim of our study was to calculate normalised rim/disc area ratio curve.

METHODS

Heidelberg Retina Tomograph examinations of the optic nerve head of 100 randomly selected eyes of 100 normal subjects were evaluated. We calculated the disc area-adjusted normalised rim/disc area ratio in sectors of 10 degrees. The 95th, 90th and 50th percentiles of each of the 36 sectors were displayed in descending order.

RESULTS

In relation to the normal percentile curves, it is possible to display an individual normalised rim/disc area ratio curve. We obtained such curves for a normal optic disc, optic nerve heads with moderate and advanced lesions and a small optic disc with glaucomatous damage.

CONCLUSION

We present a new display mode for the results of Heidelberg Retina Tomograph optic nerve head examination, which may be helpful for easy and reliable assessment of the local, diffuse and combined components of glaucomatous optic nerve head damage depending on optic disc size.

Correlation between the progression of optic disc and visual field changes in glaucoma

Visual field test and optic disc evaluation are the standard examination techniques used to detect the onset and progression of glaucoma. This explorative study was performed to assess the temporal correlation between visual field and optic disc changes in eyes with ocular hypertension and well-established glaucoma. Eighty-six hypertensive and 16 glaucomatous eyes were followed up for a period of up to 9 years (average 4.4 yrs) using kinetic and computerized static perimetry and optic disc manual morphometry. Perimetric changes were based on a series of strict criteria and optic disc changes were based as a reduction in the baseline rim area/disc area ratio (R/D) measurement exceeding the 99% confidence interval for intraobserver reproducibility (7.7%). Optic disc changes were found prior to visual field changes in four hypertensive eyes, whereas visual field changes were found prior to disc changes in six glaucomatous eyes (p = 0.042). The results of our explorative study suggest that quantitative optic disc analysis may be more sensitive than visual field examination in detecting early glaucomatous changes, whereas visual field examination may be more sensitive than quantitative optic disc analysis in detecting glaucomatous progressions in eyes with well established glaucoma.

The normalised rim/disc area ratio line

The assessment of the cup of the optic disc depends, among other criteria, on the disc area. A small cup in a small optic disc can indicate an advanced glaucomatous lesion, on the other hand a large cup in a large optic disc can be normal. Therefore, an individual normalised rim/disc area ratio line together with the curves of 50th percentile and the 95th percentile of normal could help to better distinguish between glaucomatous and normal optic cups. The aim of our study was to calculate and to evaluate such a normalised rim/disc area ratio line. Heidelberg Retina Tomograph examinations of the optic nerve head of 100 randomly selected eyes of 100 normal subjects were evaluated. We calculated the disc area adjusted rim/disc area ratio in sectors of 10 degrees. The 95th percentile and the 50th percentile of each of the 36 sectors were calculated. Based on these normal percentile lines it was possible to display an individual normalised rim/disc area ratio line in the topographic images of an individual optic disc examination. Here we demonstrated examples of a normal optic disc, optic nerve heads with moderate and advanced lesions and a small optic disc with glaucomatous damage. We present a new display mode of the results of Heidelberg Retina Tomograph optic nerve head examination, which may be helpful for an easy and reliable assessment of glaucomatous optic nerve head damage only looking at topographic images.

Covariation of optic disc measurements and ocular parameters in the healthy eye

To understand the variations in optic disc topography that may affect the local susceptibility of nerve fibers to glaucomatous damage, we evaluated the correlations between optic disc topography and selected ocular parameters in 210 normal eyes of healthy Japanese. In the total study group, eyes with a longer axial length had a longer distance between the disc and foveola, a larger index of ovalness and a larger disc (P < 0.01). A longer disc-foveola distance correlated with a larger index of ovalness (P < 0.01). The optic discs of severely myopic eyes had a considerably different structure from other eyes. Eyes with a tilted optic disc were unique in that the area of the optic disc was not large despite a positive correlation with long axial length (P < 0.01) a long disc-foveola distance (P < 0.01), and a large index of ovalness (P < 0.01). Eyes with a rotated optic disc were another special case. This eye type correlated in a contradictory fashion with two parameters: a large axial length (P < 0.01) and a short disc-foveola distance (P < 0.01). These findings suggest that changes in optic disc topography or susceptibility to glaucomatous damage correlate with selected ocular parameters but are not completely parallel.

Ocular parameters in elderly in Norway

A retrospective review of medical records of 434 patients (mean age 76.2 +/- 10.1 years) undergoing cataract surgery was performed to detect possible sex differences for several ocular parameters and their change with age. More women were operated for cataract than men by a 2:1 ratio. Their age was not significantly different. Women had higher intraocular pressure (15.4 +/- 3.5 mmHg), shorter axial length (22.98 +/- 1.31 mm) and steeper cornea (43.64 +/- 1.61D) than men (14.7 +/- 3.6 mmHg, 23.33 +/- 0.97 mm and 42.88 +/- 1.52D, respectively). For both sexes, a negative correlation between the corneal refraction and axial length was revealed. For women, a trend towards shorter eyes in the higher age groups was found. Among those older than 80 years, stronger intraocular lenses were implanted in women than in men. Based on these results, more attention should be paid to the differences between women and men regarding ocular parameters in the elderly.

Relationship between morphometric optic disc parameters, sex and axial length

Optic disc correlations were evaluated in normal eyes by means of computer-aided morphometry. Two hundred and thirty-five subjects (144 women and 91 men) entered the study. One eye per patient was randomly chosen for statistical analysis. Disc area (P < 0.05) and axial length (P < 0.0001) were statistically different between sexes. There was a correlation between axial length and both disc area (r for females = 0.55, P < 0.00001; r for males = 0.35, P < 0.0007) and refraction (r for females = 0.40, P < 0.00001; r for males = 0.50, P < 0.00001). The main findings of this investigation were that disc area is greater in male than in female eyes (thus clinically confirming the Ishi's and Quigley's previous observations of autopsy eyes) on the basis of axial length difference between the two sexes, and that disc size correlated with axial length. Disagreements in disc measurements reported in previous studies may be caused by differences in the male/female ratios of their samples.

The comparative analysis of optic disc damage in exfoliative glaucoma

To compare the initial and follow-up discernible glaucomatous neuroretinal rim (NRR) and parapapillary chorioretinal changes in patients with primary open-angle glaucoma (POAG) and exfoliative glaucoma (EG), we analyzed 40 optic discs from 40 patients with POAG, 40 optic discs from 40 patients with EG and 20 optic discs from 20 normal subjects. The mean intraocular pressure was higher in the EG group when compared with POAG (p < 0.001). Although the mean disc areas in both groups were not significantly different, the mean initial NRR area to disc area ratio was significantly smaller in patients with EG (p < 0.001). At the initial diagnosis the most prominent NRR defects of the patients with POAG were at the inferotemporal and superotemporal sectors, followed by the temporal and nasal sectors. However, the NRR in the EG group was noticed to decrease diffusely without such a sectorial preference. There was no significant difference between the mean loss of the NRR to disc area ratio in both groups at the end of the follow-up period of 1 year (p > 0.05). The values of parapapillary chorioretinal atrophy areas in POAG and EG patients were not significantly different from each other, neither at the initial examination nor during the follow-up period (p > 0.05). Those results suggest that high intraocular pressure in eyes with EG may constitute a major risk for rapid and progressive glaucomatous optic disc damage.

Assessment of optic disc topography with scanning laser ophthalmoscope

Evaluation of the topography of the optic disc is of clinical importance to assess the degree of nerve damage. We conducted a study in 17 glaucomatous and 20 control subjects with a scanning laser ophthalmoscope (SLO; Rodenstock) and compared the results with those in conventional photographs. A tomographic image of the cup area in control subjects and the neuroretinal rim area in glaucomatous subjects obtained with the SLO was smaller than that in photographs taken with a conventional camera (P < 0.05 and P < 0.01 respectively). In both the control and glaucoma groups, the optic disc area obtained with the SLO was significantly smaller than that in conventional photographs (P < 0.01). The coefficient of variation of the optic disc parameters studied with the SLO range from 4.2% to 9.1%. A correlation between the optic disc indices studied with SLO and the mean defect of the visual field was statistically significant. The tomographic images obtained by the SLO permit accurate assessment of optic nerve damage.