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Figure.
Clinical assessment of the ISNT rule for a normal optic nerve. The ISNT rule is that disc rim thickness shows a characteristic configuration of inferior (I) greater than or equal to superior (S) greater than or equal to nasal (N) greater than or equal to temporal (T) (or I≥S≥N≥T).

Clinical assessment of the ISNT rule for a normal optic nerve. The ISNT rule is that disc rim thickness shows a characteristic configuration of inferior (I) greater than or equal to superior (S) greater than or equal to nasal (N) greater than or equal to temporal (T) (or I≥S≥N≥T).

Table 1. 
Patient Demographics and Ocular Findings by Diagnosis Group
Patient Demographics and Ocular Findings by Diagnosis Group
Table 2. 
Patient Demographics and Ocular Findings by Diagnosis and Race
Patient Demographics and Ocular Findings by Diagnosis and Race
Table 3. 
Patient Demographics and Ocular Findings by Race and Diagnosis Group
Patient Demographics and Ocular Findings by Race and Diagnosis Group
1.
Greaney  MJHoffman  DCGarway-Heath  DFNakla  MColeman  ALCaprioli  J Comparison of optic nerve imaging methods to distinguish normal eyes from those with glaucoma. Invest Ophthalmol Vis Sci 2002;43140- 145
PubMed
2.
Wollstein  GGarway-Heath  DFFontana  LHitchings  RA Identifying early glaucomatous changes: comparison between expert clinical assessment of optic disc photographs and confocal scanning ophthalmoscopy. Ophthalmology 2000;1072272- 2277
PubMedArticle
3.
Jonas  JBGusek  GCNaumann  GO Optic disc, cup and neuroretinal rim size, configuration and correlations in normal eyes [published corrections appear in Invest Ophthalmol Vis Sci. 1991;321893;and Invest Ophthalmol Vis Sci 1992;32474- 475Invest Ophthalmol Vis Sci 1988;291151- 1158
PubMed
4.
Dichtl  AJonas  JBNaumann  GO Retinal nerve fiber layer thickness in human eyes. Graefes Arch Clin Exp Ophthalmol 1999;237474- 479
PubMedArticle
5.
Jonas  JBGusek  GCNaumann  GO Optic disc morphometry in chronic primary open-angle glaucoma, I: morphometric intrapapillary characteristics. Graefes Arch Clin Exp Ophthalmol 1988;226522- 530
PubMedArticle
6.
Seddon  JM The differential burden of blindness in the United States. N Engl J Med 1991;3251440- 1442
PubMedArticle
7.
Sommer  A Glaucoma risk factors observed in the Baltimore Eye Survey. Curr Opin Ophthalmol 1996;793- 98
PubMedArticle
8.
Sommer  ATielsch  JMKatz  J  et al.  Racial differences in the cause-specific prevalence of blindness in east Baltimore. N Engl J Med 1991;3251412- 1417
PubMedArticle
9.
Tielsch  JMSommer  AKatz  JRoyall  RMQuigley  HAJavitt  J Racial variations in the prevalence of primary open-angle glaucoma: the Baltimore Eye Survey. JAMA 1991;266369- 374
PubMedArticle
10.
Beck  RWMessner  DKMusch  DCMartonyi  CLLichter  PR Is there a racial difference in physiologic cup size? Ophthalmology 1985;92873- 876
PubMedArticle
11.
Chi  TRitch  RStickler  DPitman  BTsai  CHsieh  FY Racial differences in optic nerve head parameters. Arch Ophthalmol 1989;107836- 839
PubMedArticle
12.
Girkin  CAMcGwin  G  JrMcNeal  SFDeLeon-Ortega  J Racial differences in the association between optic disc topography and early glaucoma. Invest Ophthalmol Vis Sci 2003;443382- 3387
PubMedArticle
13.
Quigley  HABrown  AEMorrison  JDDrance  SM The size and shape of the optic disc in normal human eyes. Arch Ophthalmol 1990;10851- 57
PubMedArticle
14.
Varma  RTielsch  JMQuigley  HA  et al.  Race-, age-, gender-, and refractive error–related differences in the normal optic disc. Arch Ophthalmol 1994;1121068- 1076
PubMedArticle
15.
Girkin  CAMcGwin  G  JrXie  ADeLeon-Ortega  J Differences in optic disc topography between black and white normal subjects. Ophthalmology 2005;11233- 39
PubMedArticle
16.
Girkin  CAMcGwin  G  JrLong  CDeLeon-Ortega  JGraf  CMEverett  AW Subjective and objective optic nerve assessment in African Americans and whites. Invest Ophthalmol Vis Sci 2004;452272- 2278
PubMedArticle
17.
Zangwill  LMChan  KBowd  C  et al.  Heidelberg retina tomograph measurements of the optic disc and parapapillary retina for detecting glaucoma analyzed by machine learning classifiers. Invest Ophthalmol Vis Sci 2004;453144- 3151
PubMedArticle
18.
Jonas  JBDichtl  ABudde  WMLang  P Optic disc morphology in pigmentary glaucoma. Br J Ophthalmol 1998;82875- 879
PubMedArticle
19.
Jonas  JBGrundler  A Optic disc morphology in “age-related atrophic glaucoma.” Graefes Arch Clin Exp Ophthalmol 1996;234744- 749
PubMedArticle
20.
Jonas  JBGrundler  A Optic disc morphology in juvenile primary open-angle glaucoma. Graefes Arch Clin Exp Ophthalmol 1996;234750- 754
PubMedArticle
21.
Ramrattan  RSWolfs  RCJonas  JBHofman  Ade Jong  PT Determinants of optic disc characteristics in a general population: the Rotterdam Study. Ophthalmology 1999;1061588- 1596
PubMedArticle
22.
Tsai  CSRitch  RShin  DHWan  JYChi  T Age-related decline of disc rim area in visually normal subjects. Ophthalmology 1992;9929- 35
PubMedArticle
23.
Medeiros  FAZangwill  LMBowd  CWeinreb  RN Comparison of the GDx VCC scanning laser polarimeter, HRT II confocal scanning laser ophthalmoscope, and stratus OCT optical coherence tomograph for the detection of glaucoma. Arch Ophthalmol 2004;122827- 837
PubMedArticle
24.
Hoffmann  EMBowd  CMedeiros  FA  et al.  Agreement among 3 optical imaging methods for the assessment of optic disc topography. Ophthalmology 2005;1122149- 2156
PubMedArticle
25.
Racette  LBoden  CKleinhandler  SL  et al.  Differences in visual function and optic nerve structure between healthy eyes of blacks and whites. Arch Ophthalmol 2005;1231547- 1553
PubMedArticle
Clinical Sciences
November 2006

The ISNT Rule and Differentiation of Normal From Glaucomatous Eyes

Author Affiliations

Author Affiliations: Departments of Ophthalmology, The New York Eye and Ear Infirmary (Drs Harizman, Oliveira, Tello, and Ritch), New York University School of Medicine (Drs Chiang, Marmor, and Liebmann), and Manhattan Eye, Ear, and Throat Hospital (Dr Liebmann), New York, NY, and Department of Ophthalmology, New York Medical College, Valhalla, NY (Drs Harizman, Oliveira, Tello, and Ritch).

Arch Ophthalmol. 2006;124(11):1579-1583. doi:10.1001/archopht.124.11.1579
Abstract

Objective  To determine whether the ISNT rule (that normal eyes show a characteristic configuration for disc rim thickness of inferior ≥ superior ≥ nasal ≥ temporal), widely used for clinical evaluation of the optic nerve head, can differentiate normal from glaucomatous eyes.

Methods  All subjects underwent complete eye examination, including achromatic automated perimetry, simultaneous stereoscopic disc photography, and confocal scanning laser ophthalmoscopy. Subjects with normal eyes had no evidence of glaucoma or ocular hypertension and had normal perimetry measurements. Subjects with glaucoma had a reproducible visual field defect. One eye from each subject was randomly enrolled. The ISNT rule was assessed by masked evaluation of disc photographs at the 3, 6, 9, and 12 o’clock positions.

Results  Sixty-six subjects with normal eyes (33 black and 33 white individuals) and 43 with open-angle glaucoma (15 black and 28 white individuals) were enrolled. The ISNT rule was intact in 52 (79%) of 66 normal eyes and 12 (28%) of 43 glaucomatous eyes (P<.001). Multiple logistic regression indicated that the odds ratio for glaucoma associated with violation of the ISNT rule was 6.04 (95% confidence interval, 1.74-20.95) after adjustment for age; race was not a confounder of this association.

Conclusion  The ISNT rule is useful in differentiating normal from glaucomatous optic nerves and is unaffected by race.

Careful assessment of the optic nerve is essential for detection and longitudinal evaluation of glaucoma. Over the past 2 decades, a variety of new diagnostic imaging devices have been developed to augment clinical examination and facilitate early diagnosis and detection of progressive disease. Confocal scanning laser ophthalmoscopy, scanning laser polarimetry, and optical coherence tomography approach the level of experienced observers at distinguishing normal eyes from those with early to moderate glaucomatous visual field loss.1,2

The neuroretinal rim in normal eyes shows a characteristic configuration. It is usually broadest in the inferior rim, followed by the superior and nasal rims, and thinnest in the temporal disc region. This pattern of rim width is known as the ISNT rule (inferior ≥ superior ≥ nasal ≥ temporal). The ISNT rule was originally described after assessment of optic disc photographs of 457 normal eyes3and is often used in clinical practice to help detect early glaucomatous optic neuropathy. The purpose of this study was to assess the ability of the ISNT rule to differentiate healthy eyes from those with glaucoma.

METHODS

Subjects with normal eyes and those with primary open-angle glaucoma were enrolled prospectively as part of a longitudinal glaucoma study. Following approval by the institutional review board for human research of The New York Eye and Ear Infirmary, informed consent was obtained from all participants. Subjects underwent a comprehensive ophthalmologic examination that included slitlamp biomicroscopy, gonioscopy, dilated fundoscopy, Swedish Interactive Threshold Algorithm (SITA) standard 24-2 achromatic automated perimetry (Carl Zeiss Meditec, Inc, Dublin, Calif), simultaneous color stereoscopic optic disc photography (3-Dx; Nidek Inc, Fremont, Calif), and confocal scanning laser ophthalmoscopy (HRT-II; Heidelberg Engineering GmbH, Dossenheim, Germany). Visual field reliability criteria included having less than 33% fixation losses, false-positive results, and false-negative results. Exclusion criteria included age younger than 18 years, visual acuity worse than 20/40, previous incisional surgery other than uncomplicated cataract extraction, hazy media precluding reliable photography or imaging, absence of an optic cup, and ocular disease other than glaucoma.

One eye from each subject was randomly selected for enrollment. Control subjects were individuals with no history of ocular disease. All had intraocular pressures of 22 mm Hg or less on Goldmann applanation tonometry, normal optic disc appearance based on clinical examination, and normal automated achromatic perimetry results. Absence of glaucomatous optic neuropathy was defined as a vertical cup-disc asymmetry between eyes of less than 0.2, a cup-disc ratio of 0.6 or less, and an intact neuroretinal rim without notching or excavation. A normal visual field had a pattern standard deviation within the 95% normal limits and a glaucoma hemifield test result within the 99% normal limits on a reliable visual field.

Subjects with glaucoma had open angles on gonioscopy and repeatable achromatic visual field loss consistent with glaucoma. Glaucomatous visual field loss was defined as a pattern standard deviation outside the 95% normal limits or a glaucoma hemifield test result outside the 99% normal limits or both.

Simultaneous optic disc stereophotographs were evaluated during masked review by a committee of 3 observers (N.H., C.O., and J.M.L.). The observers evaluated optic nerve neuroretinal rim thickness at the inferior, superior, nasal, and temporal positions (ie, at the 3, 6, 9, and 12 o’clock positions). A decision regarding thickness of the rim and the ISNT rule was reached by consensus. The rule was considered to be intact if there was a gradual decrease or no change in rim width at these positions relative to the following order: inferior ≥ superior ≥ nasal ≥ temporal (Figure). The central retinal vessel trunk was not considered part of the neuroretinal rim.

If the ISNT rule was not intact, the consensus group was required to determine whether the inferior rim thickness was greater than or equal to that of the superior rim.

Statistical analysis was performed using JMP or SAS statistical software (SAS Institute Inc, Cary, NC). The unpaired, 2-tailed t test or nonparametric Wilcoxon rank sum test was used to compare the distributions of continuous variables between groups; the χ2 test or the Fisher exact test was used to compare categorical variables. Multiple logistic regression analysis was used to investigate the association between glaucoma and adherence to the ISNT rule while adjusting for covariates. P<.05 was considered statistically significant. Results are presented as mean ± SD unless otherwise indicated.

RESULTS

One hundred nine eyes of 109 subjects were enrolled. Sixty-six (33 white and 33 black) subjects were used as normal controls and 43 (28 white and 15 black) had glaucoma. Patient demographic and ocular characteristics are described in Tables 1, 2, and 3. Subjects with normal eyes were younger than those with glaucoma (46.1 ± 13.6 vs 61.3 ± 10.7 years; P<.001) (Table 1). Sex distribution (P = .55) and refractive error (P = .37) were similar between the 2 groups. Normal eyes had a shorter axial length than eyes with glaucoma (23.6 ± 0.9 vs 24.1 ± 1.1 mm; P = .01).

The ISNT rule was intact in 52 (79%) of 66 normal eyes and 12 (28%) of 43 glaucomatous eyes (P<.001) (Table 1). Among subjects with normal eyes, the proportion of subjects adhering to the ISNT rule did not differ by race (25 [76%] of 33 black subjects vs 27 [82%] of 33 white subjects; P = .76 by Fisher exact test) (Table 2). Among white participants, the ISNT rule was intact more often in normal eyes (27/33 [82%]) than in glaucomatous eyes (10/28 [36%]) (P<.001) (Table 3). Similarly, among black participants, the ISNT rule was intact in 25 (76%) of 33 normal eyes compared with 2 (13%) of 15 glaucomatous eyes (P<.001) (Table 3). The odds ratio (OR) for glaucoma associated with violation of the ISNT rule in black participants (OR, 20.3; 95% confidence interval [CI], 3.7-110.0) exceeded that in whites (OR, 8.1; 95% CI, 2.5-26.2), but the sample sizes were small and Breslow-Day test results indicated that the ORs were not significantly different, suggesting that race was a confounder and not an effect modifier.

Of the 14 normal eyes that violated the ISNT rule, 7 had an inferior rim that was thinner than the superior rim. Of the remaining 7 eyes, 5 had a nasal rim that was thicker than the inferior rim and 2 had a temporal rim that was thicker than the superior rim. Analysis of the vertical rim alone by diagnostic group demonstrated that the inferior rim was generally thicker than or equal to the superior rim for both normal (59/66 [89%]) and glaucomatous (26/43 [60%]) eyes. This difference between the groups was statistically significant (P<.001).

Black subjects with glaucoma in our study were significantly more myopic and had eyes with greater axial length compared with black subjects with normal eyes (P = .03 and P<.001 for refractive error and axial length, respectively) (Table 3). This difference was not seen in white subjects (P = .64 and P = .70 for refractive error and axial length, respectively) (Table 3).

The mean optic disc area measured by confocal scanning laser ophthalmoscopy was significantly larger in subjects with glaucoma (P<.001). The mean optic disc area was 1.82 ± 0.40 mm2 (range, 0.95-2.91 mm2) in subjects with normal eyes and 2.27 ± 0.60 mm2 (range, 1.49 to 3.82 mm2) in those with glaucoma (Table 1).

Multiple logistic regression analysis was performed to examine the relationship between the diagnosis of glaucoma and the ISNT rule while adjusting for potential confounders. We found significant associations of glaucoma diagnosis with violation of the ISNT rule (OR, 6.04; 95% CI, 1.74-20.95; P = .005), larger disc area (OR, 10.75; 95% CI, 2.33-49.67; P = .002), and increasing axial length (OR, 2.55; 95% CI, 1.21-5.35; P = .01) after adjusting for potential confounding due to age and race.

To achieve greater homogeneity of age between the subjects with normal eyes and those with glaucoma, we further analyzed the data, restricting the subject population to 69 individuals aged 43 to 66 years. This included 39 subjects with normal eyes (17 black and 22 white individuals, median age [range], 52 [43-60] years) and 30 subjects with open-angle glaucoma (14 black and 16 white individuals, median age [range], 55 [43-60] years). Median ages did not differ significantly between the 2 groups (P = .14). The ISNT rule was intact in 32 (82%) of 39 normal eyes and 8 (27%) of 30 glaucomatous eyes (P<.001). In multiple logistic regression modeling adjusted for age and race, we found significantly elevated ORs for glaucoma associated with violation of the ISNT rule (OR, 7.8; 95% CI, 2.1-28.6) and larger disc size (OR per unit increase, 15.0; 95% CI, 2.5-89.7).

COMMENT

The ISNT rule was originally described by Jonas et al,3who used rim area measurements of normal eyes, calculated from projected optic disc photographs. Later, retinal nerve fiber layer thickness was measured at the optic disc borders histomorphometrically and was found to follow the same rule.4This morphometric characteristic is not followed in patients with glaucoma.5The present study confirms the work of Jonas et al3,5and the utility of the ISNT rule in clinical practice in black and white subjects.

Several studies69have demonstrated a higher prevalence of open-angle glaucoma with higher rates of blindness in persons of black African ancestry compared with European-derived populations. Racial differences in ocular anatomy include larger disc and cup areas in black subjects1014with similar neuroretinal rim area, yielding an overall larger cup-disc ratio.11Girkin et al15reported that most differences in optic disc topography between black and white subjects with normal eyes became nonsignificant after adjustment for reference plane height and for optic disc area as measured by confocal scanning laser ophthalmoscopy. Girkin and colleagues16also demonstrated that racial differences in optic disc structure had little impact on the relative ability of subjective and objective methods to discriminate between glaucomatous and normal optic discs. One could therefore expect the neural rim to follow the ISNT rule regardless of race. In the present case study, race and age were treated as potential confounders, and multivariable logistic regression techniques were used to control for the potential effects of imbalances in these variables between groups.

The nasal sector of the optic nerve is more difficult to evaluate owing to obscuration of the rim by the exit of large retinal vessels. We tested the hypothesis that the inferior-superior rim relationship alone would simplify the detection of a suspicious optic disc. However, this turned out not to be the case. In future studies, evaluation of the temporal disc region compared with the other 3 rim sectors may increase specificity in detecting glaucomatous optic discs because the vertical rim is frequently affected before the horizontal rim.

Several studies5,1720have found equal optic disc sizes in both normal and glaucomatous eyes, while others12have demonstrated larger disc areas in glaucomatous eyes. Optic disc area in the present study was greater in the glaucomatous eyes than in the normal eyes for both races, as well as in the combined racial group. The ISNT rule remained a predictor of a glaucoma diagnosis after controlling for multiple factors including disc area.

Despite the fact that there is axonal loss with age, it remains controversial whether age affects the neuroretinal rim area.14,21,22It is unlikely that the greater age of the patients with glaucoma significantly affected the relative rim thickness at the different locations. In the multivariate analysis on the age-matched groups (n = 69), the ISNT rule kept its diagnostic ability in detecting glaucoma.

The present study has several limitations. The sample size is relatively small, and in a larger cohort violation of the ISNT rule could be correlated with visual field status and disease severity. Although glaucoma was defined strictly based on functional criteria, in the evaluation of normal eyes we could not avoid the inclusion of optic nerve information typically obtained during a routine eye examination. One could argue that this bias would favor inclusion of normal eyes that adhere to the ISNT rule, yet the fact that more than 20% of our normal eyes violated the ISNT rule suggests that this potential bias was minimal. The reality of glaucoma structure and function research is that the visual field, intraocular pressure, and optic disc are always examined in every patient entering any imaging or visual function study. Our definition of normal eyes used previously published standard criteria that include an optic disc examination in addition to functional testing.2325We intentionally excluded glaucoma suspect eyes and eyes with preperimetric glaucoma to facilitate the comparison between normal and glaucomatous eyes. Future studies should address the use of the ISNT rule for these individuals. Finally, our results can be applied only to patients with a similar range of refractive error.

The present study suggests that the ISNT rule is a clinically useful method to aid in glaucoma diagnosis and risk assessment in clinical practice. Although differences in optic nerve anatomy exist between black and white subjects, our results suggest that the ISNT rule can be applied equally to white and black individuals.

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Article Information

Correspondence: Jeffrey M. Liebmann, MD, Department of Ophthalmology, The New York Eye and Ear Infirmary, 310 E 14th St, Suite 304, New York, NY 10003 (jml18@earthlink.net).

Submitted for Publication: June 29, 2005; final revision received June 29, 2006; accepted July 2, 2006.

Financial Disclosure: None reported.

Funding/Support: This study was supported in part by the New York Eye and Ear Infirmary Department of Ophthalmology Research Fund, the Jason Alexander Foundation, the New York Glaucoma Research Institute, and an American Physicians Fellowship for Medicine in Israel (Dr Harizman).

Previous Presentation: This study was presented in part at the Annual Meeting of the Association for Research in Vision and Ophthalmology; May 5, 2005; Fort Lauderdale, Fla.

References
1.
Greaney  MJHoffman  DCGarway-Heath  DFNakla  MColeman  ALCaprioli  J Comparison of optic nerve imaging methods to distinguish normal eyes from those with glaucoma. Invest Ophthalmol Vis Sci 2002;43140- 145
PubMed
2.
Wollstein  GGarway-Heath  DFFontana  LHitchings  RA Identifying early glaucomatous changes: comparison between expert clinical assessment of optic disc photographs and confocal scanning ophthalmoscopy. Ophthalmology 2000;1072272- 2277
PubMedArticle
3.
Jonas  JBGusek  GCNaumann  GO Optic disc, cup and neuroretinal rim size, configuration and correlations in normal eyes [published corrections appear in Invest Ophthalmol Vis Sci. 1991;321893;and Invest Ophthalmol Vis Sci 1992;32474- 475Invest Ophthalmol Vis Sci 1988;291151- 1158
PubMed
4.
Dichtl  AJonas  JBNaumann  GO Retinal nerve fiber layer thickness in human eyes. Graefes Arch Clin Exp Ophthalmol 1999;237474- 479
PubMedArticle
5.
Jonas  JBGusek  GCNaumann  GO Optic disc morphometry in chronic primary open-angle glaucoma, I: morphometric intrapapillary characteristics. Graefes Arch Clin Exp Ophthalmol 1988;226522- 530
PubMedArticle
6.
Seddon  JM The differential burden of blindness in the United States. N Engl J Med 1991;3251440- 1442
PubMedArticle
7.
Sommer  A Glaucoma risk factors observed in the Baltimore Eye Survey. Curr Opin Ophthalmol 1996;793- 98
PubMedArticle
8.
Sommer  ATielsch  JMKatz  J  et al.  Racial differences in the cause-specific prevalence of blindness in east Baltimore. N Engl J Med 1991;3251412- 1417
PubMedArticle
9.
Tielsch  JMSommer  AKatz  JRoyall  RMQuigley  HAJavitt  J Racial variations in the prevalence of primary open-angle glaucoma: the Baltimore Eye Survey. JAMA 1991;266369- 374
PubMedArticle
10.
Beck  RWMessner  DKMusch  DCMartonyi  CLLichter  PR Is there a racial difference in physiologic cup size? Ophthalmology 1985;92873- 876
PubMedArticle
11.
Chi  TRitch  RStickler  DPitman  BTsai  CHsieh  FY Racial differences in optic nerve head parameters. Arch Ophthalmol 1989;107836- 839
PubMedArticle
12.
Girkin  CAMcGwin  G  JrMcNeal  SFDeLeon-Ortega  J Racial differences in the association between optic disc topography and early glaucoma. Invest Ophthalmol Vis Sci 2003;443382- 3387
PubMedArticle
13.
Quigley  HABrown  AEMorrison  JDDrance  SM The size and shape of the optic disc in normal human eyes. Arch Ophthalmol 1990;10851- 57
PubMedArticle
14.
Varma  RTielsch  JMQuigley  HA  et al.  Race-, age-, gender-, and refractive error–related differences in the normal optic disc. Arch Ophthalmol 1994;1121068- 1076
PubMedArticle
15.
Girkin  CAMcGwin  G  JrXie  ADeLeon-Ortega  J Differences in optic disc topography between black and white normal subjects. Ophthalmology 2005;11233- 39
PubMedArticle
16.
Girkin  CAMcGwin  G  JrLong  CDeLeon-Ortega  JGraf  CMEverett  AW Subjective and objective optic nerve assessment in African Americans and whites. Invest Ophthalmol Vis Sci 2004;452272- 2278
PubMedArticle
17.
Zangwill  LMChan  KBowd  C  et al.  Heidelberg retina tomograph measurements of the optic disc and parapapillary retina for detecting glaucoma analyzed by machine learning classifiers. Invest Ophthalmol Vis Sci 2004;453144- 3151
PubMedArticle
18.
Jonas  JBDichtl  ABudde  WMLang  P Optic disc morphology in pigmentary glaucoma. Br J Ophthalmol 1998;82875- 879
PubMedArticle
19.
Jonas  JBGrundler  A Optic disc morphology in “age-related atrophic glaucoma.” Graefes Arch Clin Exp Ophthalmol 1996;234744- 749
PubMedArticle
20.
Jonas  JBGrundler  A Optic disc morphology in juvenile primary open-angle glaucoma. Graefes Arch Clin Exp Ophthalmol 1996;234750- 754
PubMedArticle
21.
Ramrattan  RSWolfs  RCJonas  JBHofman  Ade Jong  PT Determinants of optic disc characteristics in a general population: the Rotterdam Study. Ophthalmology 1999;1061588- 1596
PubMedArticle
22.
Tsai  CSRitch  RShin  DHWan  JYChi  T Age-related decline of disc rim area in visually normal subjects. Ophthalmology 1992;9929- 35
PubMedArticle
23.
Medeiros  FAZangwill  LMBowd  CWeinreb  RN Comparison of the GDx VCC scanning laser polarimeter, HRT II confocal scanning laser ophthalmoscope, and stratus OCT optical coherence tomograph for the detection of glaucoma. Arch Ophthalmol 2004;122827- 837
PubMedArticle
24.
Hoffmann  EMBowd  CMedeiros  FA  et al.  Agreement among 3 optical imaging methods for the assessment of optic disc topography. Ophthalmology 2005;1122149- 2156
PubMedArticle
25.
Racette  LBoden  CKleinhandler  SL  et al.  Differences in visual function and optic nerve structure between healthy eyes of blacks and whites. Arch Ophthalmol 2005;1231547- 1553
PubMedArticle
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