Glaucomatous Disc Changes Research Articles

Screening for Glaucomatous Disc Changes Prior to Diagnosis of Glaucoma in Myocilin Pedigrees

To investigate whether structural differences of the optic nerve head are evident in young people who do not have manifest glaucoma but are known to carry myocilin mutations. A case-control design was adopted. Subjects from Australian pedigrees known to have either the Gln368STOP myocilin mutation (cutoff age, <40 years) or the Thr377Met myocilin mutation (cutoff age, <30 years) were examined for signs of glaucoma. Stereoscopic disc photographs were digitalized. Analysis of the optic disc area, optic cup area, and neuroretinal rim area was performed using digital stereoscopy with a Z-screen. Mutation analysis was conducted using direct sequencing. The t test, corrected for multiple comparison testing, was used in analysis. A total of 29 myocilin mutation-carrying (case) and 33 mutation-free (control) individuals were reviewed. The mean +/- SD ages were 19.9 +/- 9.0 and 22.1 +/- 9.5 years in the mutation and mutation-free groups, respectively (P = .35). There was no significant difference in intraocular pressure between mutation carriers and noncarriers (P = .44). There were no statistically significant differences in the mean disc, neuroretinal rim, and cup areas between the groups. The mean +/- SD neuroretinal rim area was 1.24 +/- 0.24 mm(2) in the noncarrier group and 1.25 +/- 0.23 mm(2) in the mutation group (P = .46). No notch, nerve fiber layer defect, or neuroretinal rim hemorrhage was noted in any eye examined. Although confounded by penetrance and expressivity, no quantified structural difference in the optic nerve head was observed in individuals who had a myocilin mutation prior to the diagnosis of glaucoma.

Moderate to severe obstructive sleep apnoea patients is associated with a higher incidence of visual field defect

To compare the visual fields (VFs) and optic nerve head changes between obstructive sleep apnoea (OSA) in normotensive patients and an age-matched non-OSA population. Case-control study. A total of 41 ethnic Chinese patients diagnosed with moderate to severe OSA referred from the Sleep Laboratory, ENT Department, Tuen Mun Hospital. A total of 35 age-matched non-OSA subjects recruited from the Ophthalmology Department, North District Hospital. Comprehensive ophthalmological and systemic history, complete ophthalmological examination, including central-30 computerized perimetry for all studied patients. Polysomnographic data, VF indices, optic disc changes. In the OSA arm, VF indices were significantly subnormal and the incidence of suspicious glaucomatous disc changes was four times higher than that of the control arm. None of the studied patients suffered from any form of anterior segment complications. Moderate to severe OSA is associated with a higher incidence of VF defect and glaucomatous optic nerve changes.

Intraocular pressure asymmetry and undiagnosed open-angle glaucoma in an older population

PurposeTo quantify prevalence of asymmetric intraocular pressure (IOP) and assess associations with undiagnosed open-angle glaucoma. DesignPopulation-based cross-sectional study. MethodsParticipants underwent applanation tonometry. Intraocular pressure asymmetry was defined for differences ≥ 3 mm Hg; open-angle glaucoma was diagnosed if glaucomatous optic disk and field changes were congruous. Analyses excluded subjects using glaucoma medication, known glaucoma, pseudoexfoliation, and cataract surgery. ResultsIntraocular pressure asymmetry was present in 5.1% of subjects and was greater for patients older than 70 years (6.2%). Of subjects with maximum IOP > 21 mm Hg, IOP asymmetry was present in 41.1%. Undiagnosed open-angle glaucoma was more frequent among subjects with (4.8%) than without (1.2%) IOP asymmetry. This relationship remained significant for maximum IOP ≤ 21 mm Hg. ConclusionsIntraocular pressure asymmetry may be a useful sign of undiagnosed glaucoma in subjects without elevated IOP.

Relationship of optic disk topography and visual function in patients withlarge cup-to-disk ratios

Purpose To determine if topographic differences exist between large cup-to-disk ratio (C/D) eyes with standard achromatic automated perimetry (SAP) abnormalities and those with only short-wavelength automated perimetry (SWAP) abnormalities. Design Cross-sectional study. Methods The setting was a referral university-based clinical practice. We selected one eye of 72 patients with a vertical C/D of at least 0.8 by ophthalmoscopy. Patients performed SWAP, SAP, and confocal scanning laser ophthalmoscopy. We compared optic disk topography in eyes with and without visual field abnormalities and controlled for the influence of disk area. Results Disk area was a confounder of many topographic measures. After controlling for disk area, eyes with abnormal SAP had differences in rim volume, cup shape, rim area, retinal nerve fiber layer thickness, and retinal nerve fiber layer cross-sectional area when compared with eyes with normal SAP ( P < .05). Rim volume and rim area were different in the SWAP comparison ( P < .05). Conclusions Investigators should control for disk area when evaluating topographic measures by confocal scanning laser ophthalmoscopy. In eyes with a large C/D, optic disk topography is more glaucomatous in eyes with SAP abnormalities than in those with only SWAP abnormalities. Eyes with large C/D and only SWAP abnormalities may have fewer glaucomatous optic disk changes than such eyes with SAP abnormalities. This indicates that SWAP is likely to correspond to abnormalities in optic disk topography at an earlier stage of glaucomatous optic neuropathy than SAP. Therefore, clinicians should consider SWAP testing in glaucoma suspects to detect glaucomatous visual field loss at an earlier stage of structural loss.

Prevalence of open-angle glaucoma in Iceland: Reykjavik Eye Study.

To establish the age- and sex-specific prevalence of open-angle glaucoma (OAG) subsuming pseudoexfoliation (PEX) in the city of Reykjavik. Participants 50 years of age and older who were part of the Reykjavik Eye Study and classified as having glaucoma were divided into three categories:Category 1: two or more of the following based on optic nerve stereophotograph reading: vertical cup to disc ratio (VCDR) 97.5th percentile (>0.7), focal glaucomatous disc change, C/D asymmetry of 97.5th percentile difference between eyes (>0.2) as well as glaucomatous visual field defect (GVFD). Category 2: 99.5th percentile of VCDR (>0.8) and 99.5% percentile difference between eyes (>/=0.3), without a GVFD. Category 3: VA<3/60 and IOP>99.5th percentile or VA <3/60 and evidence of filtering surgery. For a glaucoma suspect, one of the following was present: VCDR>99.5th percentile (>0.8), focal glaucomatous disc change, C/D asymmetry of 99.5th percentile (> or =0.3), GVFD only, IOP> or =23 mmHg (97.5 percentile). PEX was diagnosed by the presence of a central shield and/or a peripheral band on the anterior lens capsule. Of 42 persons (22 males and 20 females) with OAG, 13 (31.0%) had PEX. The minimum prevalence of OAG was 4.0% (42/1045) (95% CI 2.8-5.2) for those 50 years and older and 10.3% (95% CI 8.5-12.2) for PEX. The prevalence of OAG increases with age (OR=1.10/year, 95% CI 1.07-1.13, P=0.000) and the same applies for the prevalence of PEX, OR=1.10 (95% CI 1.07-1.12, P=0.000). There is a 10% annual increase for both OAG and PEX in persons 50 years and older.

Disc haemorrhages, precursors of open angle glaucoma.

In a long-term study of 1270 patients with at least one of the findings, open-angle glaucoma, disc haemorrhages or retinal vein occlusions, disc haemorrhages were witnessed in approximately 20% of the cases with open-angle glaucoma, and were a precursor of glaucomatous disc changes and associated visual field defects. Disc haemorrhages also preceded a rising intraocular pressure (IOP) in the destructive process among open-angle glaucoma cases. Similar glaucomatous development appears among cases independent of IOP or detection of exfoliation syndrome. Retinal vein occlusions and disc haemorrhages behave similarly with respect to glaucoma. The large number of transgressions is an argument against dividing glaucoma into different types. These findings support a vascular genesis to open-angle glaucoma, presented in earlier epidemiological studies.

Slope analysis of the optic disc in eyes with ocular hypertension and early normal tension glaucoma by confocal scanning laser ophthalmoscope

AIMSTo determine whether quantitative differences in sector based slope can differentiate between eyes with ocular hypertension with and without glaucomatous disc changes and eyes with normal tension glaucoma with glaucomatous...

Telemedicine Screening of Glaucoma

Glaucoma is a major cause of blindness. More than 80,000 Americans suffer permanent vision loss from the disease. Widespread screening is fundamental in limiting the incidence of glaucoma-associated blindness. This pilot study explored the use of stereo digital images taken at a primary care center for telemedicine review by an off-site specialist as a means of screening for glaucoma. Thirty-two diabetic patients were screened at a family medicine clinic. None had previously been diagnosed with glaucoma. A senior optometry student took stereoscopic digital and 35-mm optic disc photographs with a nonmydriatic retinal camera. The digital images were forwarded to a remote ophthalmologist for review. The conventional color stereo slide pairs of the same eyes were subsequently reviewed for comparison. Agreement on signs of glaucomatous disc changes between the two imaging systems was analyzed. Twenty-six of 32 eyes' digital and 35-mm photographs were analyzed. Six of 32 eyes (18.8%) could not be compared due to lack of matching 35-mm slides or digital images. Out of 26 eyes, lamina cribosa visibility was undeterminable in 8 eyes' digital images and 3 other eyes' 35-mm slides. Agreement among digital images and 35-mm slides of the remaining eyes was: 100%-vertical elongation, barring of vessels, bayoneting of vessels, and drance hemorrhage; 96.2%-focus notching of rim and rim pallor; 93.3%-lamina cribosa visability; 92. 3%-overpass cupping; 88.5%-focal enlargement; 84.6%-parapapillary halo; 80%-nerve fiber visibility; 65.4%-parapapillary atrophy. Parapapillary halo (p = 0.046) and nerve fiber layer visibility (p = 0.18) were detected on some 35-mm slides but not seen on matching digital views. Evaluations of cup-to-disc ratio (C/D) using both methods were in general agreement. However, some digital images were noted as too dark for assessing fine glaucomatous disc changes. Stereo digital images taken with a nonmydriatic camera by nonophthalmic photographers is a promising alternative for glaucoma screening in primary care settings. Telemedicine offers efficient communications with off-site glaucoma specialists. A larger study population is necessary to determine the overall effectiveness of using stereo digital imagery and teleophthalmology for glaucoma screening.

Factors associated with use of glaucoma medications in a population of older people: The Blue Mountains Eye Study

To examine factors associated with use of glaucoma medications in a population of older people. The Blue Mountains Eye Study examined 3654 people aged 49-97 years. Participants completed an interviewer-administered questionnaire which included information on current medication use. Open-angle glaucoma (OAG) was diagnosed if matching glaucomatous visual field defects and optic disc cupping were present. Ocular hypertension (OH) was diagnosed in subjects without glaucomatous disc and field changes who had an intraocular pressure (IOP) of > or = 22 mmHg in either eye or who had lower IOP levels but reported treatment with glaucoma medication. Use of glaucoma medication was reported by 3.3% of persons in this population (119/3644), including 44% of OAG and 28% of OH cases. Among newly diagnosed OAG and OH cases, 30% had never visited an ophthalmologist. Factors associated with a previous diagnosis of OAG or OH in a multivariate model included use of one or more general medications (OR 7.5; 95% CI 2.5-22.9), a history of other eye disease (OR 3.4; 95% CI 1.9-6.2) and first-degree family history of glaucoma (OR 3.6; 95% CI 1.8-7.2). Glaucoma screening may need to target individuals with OAG risk factors who are less likely to visit a general practitioner or ophthalmologist.

Open-angle Glaucoma and Diabetes: The Blue Mountains Eye Study, Australia

The authors explore the relationship between diabetes and open-angle glaucoma in a defined older Australian population. Three thousand six hundred fifty-four people 49 to 96 years of age, living west of Sydney, underwent a detailed eye examination. This included automated perimetry, stereo optic disc photographs, and applanation tonometry; in addition, fasting plasma glucose levels were ascertained. Glaucoma was diagnosed if matching visual field and optic disc cupping were present, without reference to intraocular pressure (IOP) level. Ocular hypertension (OH) was diagnosed if IOP in either eye was > or = 22 mm and glaucomatous disc and visual field changes were absent. Glaucoma prevalence was increased in people with diabetes, diagnosed from history or elevated fasting plasma glucose level (5.5%), compared with those without diabetes (2.8%; age-gender adjusted odds ratio [OR] 2.12, 95% confidence intervals [CI] 1.18-3.79). Ocular hypertension was also more common in people with diabetes (6.7%), compared with those without diabetes (3.5%; OR 1.86, CI 1.09-3.20). Diabetes was present in 13.0% of people with glaucoma, compared with 6.9% of those without glaucoma. This increase was highest for previously diagnosed glaucoma cases (16.7%; OR 2.82, CI 1.35-5.87). However, in 67% of such cases, glaucoma was diagnosed before the diabetes. For those not receiving glaucoma treatment, IOP was consistently slightly higher in people with diabetes, with the age-gender adjusted mean IOP 0.6 mm higher. The significant and consistent association between diabetes and glaucoma found in our study, which appeared independent of the effect of diabetes on IOP, suggests that there is a real association between these two diseases.

Intraocular pressure and prevalence of glaucoma in elderly people in Finland: a population-based study.

The distribution of intraocular pressure (IOP) and the prevalence of glaucoma and their correlates were studied in a population-based study of inhabitants aged 70 years or older of three communities in the county of Oulu, Finland. 500 of the 560 eligible subjects (89%) were examined. IOP was measured using applanation tonometry. The diagnosis of glaucoma (or suspected glaucoma) was based on previous history and/or characteristic optic disc changes assessed first by ophthalmoscopy and later by photographic evaluation. No correlation existed between IOP level and age, but IOP was higher in women than in men. Glaucoma occurred in 12% of the participants (60 of 500 persons). In 42 of the 60 persons (8% of the participants) glaucoma had been diagnosed before this survey: non-exfoliative open-angle glaucoma in 15 persons (3.0%), bilateral or unilateral exfoliative open-angle glaucoma in 19 persons (3.8%), and congestive glaucoma in 8 persons (1.6%). In another 18 persons (4% of the participants) new open-angle glaucoma was detected, one third of these were exfoliative. In addition, 6% of the study population had suspected glaucomatous disc changes. In all new glaucoma cases and in all suspected cases the IOP was lower than 25 mmHg. Ocular hypertension (> or = 25 mmHg) without disc changes was found in 2%.

Optic Disk Cupping and Pallor Measurements of Patients with a Disk Hemorrhage

We evaluated whether the rate of occurrence of glaucomatous disk damage in eyes with an optic disk hemorrhage differed from the rate of occurrence in control eyes. We compared 24 patients with a disk hemorrhage to 24 control patients, who had been matched for diagnosis, disk appearance, and visual fields. Cup volume and cup-to-disk area ratio of the optic disk were measured using the stereophotogrammetric technique, and area of pallor was measured using computerized image analysis. We found that diabetes increased the probability that a patient would have a disk hemorrhage, and that a hemorrhage was associated with progression of glaucomatous disk changes in half of the cases during the mean 3.1-year follow-up period. However, the mean rate of glaucomatous disk damage in patients with a hemorrhage was not different from matched control patients. A disk hemorrhage is a sign of later disk damage, but it does not alter the rate of glaucomatous disk progression.

Increased Pressure of Dilated Episcleral Veins with Open-angle Glaucoma without Exophthalmos

Six unilateral cases and one bilateral case of dilated episcleral veins with elevated intraocular pressure without exophthalmos are described. Episcleral venous pressure measured on six unilateral cases showed increased pressure in the affected eye compared to the other eye and to normal controls. Two eyes had typical glaucomatous disc and visual field changes. Five had more optic disc cupping and pallor in the eye with the elevated episcleral venous pressure and intraocular pressure. A thorough work-up, including orbital venography in two unilateral cases, carotid arteriography in one and episcleral fluorescein angiography in five cases, failed to show venous obstruction or direct arterio-venous communications. The differential diagnoses are discussed. This condition should be considered in unilateral or asymmetrical intraocular pressure elevation and in those patients with chronically red eyes without discharge.

Optic Atrophy and Glaucomatous Cupping

We reviewed 170 eyes of 112 patients with optic atrophy from various causes. Special attention was directed towards measured cup:disk ratios as well as presence of glaucomatous-like cupping of the optic nerve head. We observed a small but significant increase in nerve head cupping in eyes with optic atrophy when compared to contralateral eyes, as well as to eyes of 50 diabetic patients. No characteristic glaucomatous disk changes were documented. We evaluated these findings with respect to possible causes of glaucomatous disk and field changes.

Systemic Hypotension and Glaucomatous Changes

We undertook a prospective study to determine the frequency of development of glaucomatous disk or field changes in a series of patients who had survived at least one episode of shock with poor peripheral tissue perfusion. In 18 patients with 26 distinct episodes of shock we were unable to demonstrate any glaucomatous disk or field changes.