Should diabetic patients be screened for glaucoma? DARTS/MEMO Collaboration

Diabetes, glycemic control and risk of medical glaucoma treatment: A population-based case-control study

Purpose:

To examine the association between diabetes and risk of medical glaucoma treatment and to assess the role of long-term glycemic control in the putative association.

Design:

Population-based case-control study.

Methods:

Cases of treated glaucoma were all persons filling at least three prescriptions for glaucoma medication for the first time within one year between 2001 and 2006 in Northern Jutland, Denmark. We used risk set sampling to select 10 gender- and age-matched general population controls per case using the Danish Civil Registration System. Data on diabetes, comorbidities, and laboratory tests, including glycosylated hemoglobin (as a measure of glycemic control) were obtained from population-based medical registries. We calculated odds ratio (OR) as an estimate of relative risk for treated glaucoma comparing patients with and without diabetes, adjusted for comorbid conditions and medication use.

Results:

We included 5,991 persons with incident medical glaucoma treatment and 59,910 population controls. The adjusted OR for treated glaucoma for patients with diabetes was 1.81 (95% confidence interval: 1.65–1.98). The strength of the association between diabetes and glaucoma risk did not vary by diabetes duration or by the level of glycemic control.

Conclusions:

Regardless of glycemic control, diabetes is associated with a substantially increased risk for medical glaucoma treatment.

[Combined glaucoma and diabetic retinopathy screening in Burgundy]

INTRODUCTION

The aim of this study was to evaluate the yield of glaucoma and ocular hypertension (OHT) screening in association with diabetic retinopathy (DR) screening in a rural population.

PATIENTS AND METHODS

676 patients were screened between 2004 and 2005. The four departments the Burgundy region were visited, divided into 39 areas with sparse medical services. Each patient had fundus photographs taken with a nonmydriatic camera and IOP measurement in each eye with a noncontact tonometer. Optic discs were classified into suspect or normal.

RESULTS

On the 676 screened patients, 41 presented an anomaly (6.1%): 31 with OHT (4.6%), 7 with a suspect optic disc (1.0%), and 3 with both anomalies (0.4%). After further control, we finally found 4 cases of OHT (0.6%) and 8 cases of glaucoma (1.2%). This screening program allowed the diagnosis of 2 new cases of OHT (0.3%) and 4 new cases of glaucoma (0.6%).

DISCUSSION

This screening improved the quality of the ophthalmic follow-up in rural areas for diabetics. Furthermore, it is a simple and not more expensive way to screen for OHT and glaucoma in these populations.

CONCLUSION

The itinerant screening of OHT and glaucoma combined with a diabetic retinopathy screening is effective. The screening campaign was renewed for 2 years in semi-rural zones.

[Primary open-angle glaucoma and systemic diseases]

The exact pathomechanism of primary open-angle glaucoma (POAG) is still not completely understood. Besides elevated intraocular pressure, which has been identified as a major risk factor, there is mounting evidence for the involvement of systemic factors in the development of glaucomatous damage. Systemic peculiarities described in POAG include cardiovascular, endocrine, neurodegenerative, and sleep alterations. However, some of the studies available on systemic findings in glaucoma patients are contradictory, making further research necessary to identify the exact role of such disturbances in the pathogenesis of the damage. Another difficulty is that many studies are limited by their small sample size, their retrospective nature, and potential selection bias, thus making data interpretation more difficult. Moreover, it is not always clear whether we are dealing with coincidence or a true association between glaucoma and a particular systemic disease. Nevertheless, there is ample evidence for the involvement of vascular factors such as vascular dysregulation and blood pressure in the pathogenesis of POAG.

Rho GTPase/Rho kinase inhibition as a novel target for the treatment of glaucoma

Rho kinase (ROCK1 and ROCK2) is a serine/threonine kinase that serves as an important downstream effector of Rho GTPase, and plays a critical role in regulating the contractile tone of smooth muscle tissues in a calcium-independent manner. Several lines of experimental evidence indicate that modulating ROCK activity within the aqueous humor outflow pathway using selective inhibitors could achieve very significant benefits for the treatment of increased intraocular pressure in patients with glaucoma. The rationale for such an approach stems from experimental data suggesting that both ROCK and Rho GTPase inhibitors can increase aqueous humor drainage through the trabecular meshwork, leading to a decrease in intraocular pressure. In addition to their ocular hypotensive properties, inhibitors of both ROCK and Rho GTPase have been shown to enhance ocular blood flow, retinal ganglion cell survival and axon regeneration. These properties of the ROCK and Rho GTPase inhibitors indicate that targeting the Rho GTPase/ROCK pathway with selective inhibitors represents a novel therapeutic approach aimed at lowering increased intraocular pressure in glaucoma patients.

A computer-based diagnosis system for early glaucoma screening

Glaucoma is a serious eye disease and the major cause of blindness worldwide. Glaucoma screening is a useful way in detecting the disease at an early stage. This paper presents a computer-based glaucoma screening system in which optic nerve defects detection, visual field examination, and expert system rules are combined to increase the sensitivity and specificity. Several fundus image processing methods are used and a histogram model is given especially for combed hair retinal nerve fiber layer defect. A visual field test performed on computer monitor is adopted to reduce the cost for other perimetry equipments. The assistant diagnostic module can give a primary diagnosis based on a set of fuzzy rules. The system is cost effective and suitable for detecting early stage glaucoma, especially for large-scale screening.

Relationship between short wavelength perimetry and central corneal thickness values in ocular hypertensive subjects

PURPOSE

To evaluate the results of short wavelength perimetry (SWAP) of ocular hypertensive (OHT) patients and correlate these findings with central corneal thickness (CCT) measurements.

METHODS

Thirty-seven OHT patients with a mean age of 50.2+/-8.2 (SD) years and 30 control subjects with a mean age of 50.3+/-8.5 (SD) years were included in this study. A questionnaire was applied to patients to evaluate the demographic risk factors that may predict glaucoma development. After a detailed ophthalmologic examination, achromatic and short wavelength perimetries and ultrasonic pachymetry were performed and the results were compared between the two groups with Student t test and Mann-Whitney U test. A p value<0.05 is considered as statistically significant.

RESULTS

Mean CCT was higher in the OHT group (right eye; 558.13+/-28.39 microm and left eye; 558.94+/-27.30 microm) when compared with the control subjects (524.66+/-30.53 microm and 525.86+/-30.46 microm, respectively) (p<0.01). A significant positive correlation was found between CCT measurements and intraocular pressure (r=0.5, p<0.001). Four right eyes (10.8%) and five left eyes (13.5%) of OHT patients had defects in SWAP. OHT patients with SWAP abnormalities had significantly lower CCT measurements in right (527.25+/-17.34 microm) and left eye (528.80+/-13.60 microm) when compared with OHT patients without SWAP defects (561.87+/-27.29 microm and 563.65+/-25.92 microm, respectively) (p<0.05). Significant correlations were found between CCT and SWAP MD, PSD, and CPSD (p<0.05).

CONCLUSIONS

OHT patients with SWAP abnormalities had significantly lower CCT measurements than those without. CCT is considered as a risk factor for the development of glaucomatous damage in OHT patients.

A Sick Eye in a Sick Body? Systemic Findings in Patients with Primary Open-angle Glaucoma

Despite intense research, the pathogenesis of primary open-angle glaucoma (POAG) is still not completely understood. There is ample evidence for a pathophysiological role of elevated intraocular pressure; however, several systemic factors may influence onset and progression of the disease. Systemic peculiarities found in POAG include alterations of the cardiovascular system, autonomic nervous system, immune system, as well as endocrinological, psychological, and sleep disturbances. An association between POAG and other neurodegenerative diseases, such as Alzheimer disease and Parkinson disease, has also been described. Furthermore, the diagnosis of glaucoma can affect the patient's quality of life. By highlighting the systemic alterations found in POAG, this review attempts to bring glaucoma into a broader medical context.

Diabetes mellitus as a risk factor for glaucomatous optic neuropathy

Open-angle glaucoma (OAG) is an optic neuropathy characterized by progressive retinal ganglion cell (RGC) death and optic disk excavation. Evidence is accumulating that RGC apoptosis is the fundamental pathology of OAG. Among several risk factors for development and progression of OAG, inclusion of comorbid diabetes has been controversial. Some large population-based prevalence and incidence studies found a positive association between diabetes and OAG, whereas others did not. This inconsistency is derived from selection-, recall-, or survival-bias or misclassification due to low incidence of the two diseases. On the other hand, recent basic studies have shown that diabetes not only affects vascular tissues but also compromises neuronal and glial functions and metabolism in the retina, which ultimately gives rise to apoptotic death of retinal neurons including RGCs. The impaired metabolism of neurons and glia by diabetes may render RGCs susceptible to additional stresses related to OAG such as elevated intraocular pressure. In fact, our latest data demonstrate that retinas taken from rats with streptozotocin-induced diabetes, which underwent cauterization of three episcleral veins to become a chronic glaucoma model, had significantly more apoptotic cells than those from rats with diabetes alone or with chronic glaucoma alone. In this regard, diabetes is a 'risk factor' for glaucomatous optic neuropathy. Additionally, prospective studies are needed to determine if OAG patients with diabetes have a more aggressive course than those without diabetes.

Diabetes mellitus as a risk factor for primary open-angle glaucoma: a meta-analysis

AIM

The association of diabetes mellitus with primary open-angle glaucoma has been controversial. The study aimed to examine the strength of this association through a detailed meta-analysis of studies published in peer-reviewed journals.

METHODS

A comprehensive search for articles published through 2002 was performed and data were abstracted. Prior to meta-analysis, all studies were evaluated for publication bias and heterogeneity. Pooled odds ratio (OR) was calculated using the random and the fixed-effects model.

RESULTS

Twelve studies published between 1987 and 2001 were included (five case-control studies and seven cross-sectional studies). Significant heterogeneity among the studies was detected (P = 0.023). No evidence of publication bias was found (P = 0.37). The association of diabetes mellitus with primary open-angle glaucoma was statistically significant assuming either a random effects [OR = 1.50, 95% confidence interval (CI) 1.16, 1.93], or a fixed-effects model (OR = 1.27, 95% CI 1.10, 1.45).

CONCLUSIONS

Our meta-analysis results suggest that diabetic patients are at significantly increased risk of developing primary open-angle glaucoma. Clinicians should be aware of this possibility.

Analysis of risk factors that may be associated with progression from ocular hypertension to primary open angle glaucoma

BACKGROUND

As a multifactorial disease, glaucoma may be associated with pressure-dependent and pressure-independent factors. Ocular hypertension (OHT) may develop into primary open angle glaucoma (POAG) for many patients. Groups with OHT and POAG were compared for pressure-dependent and independent risk factors. A high prevalence of any factor(s) could indicate a contribution to progression from OHT to POAG.

METHODS

A sample of patients with POAG (n = 438) and with OHT (n = 301) were selected from those attending a tertiary referral private glaucoma practice, and data were collected regarding age and intraocular pressure at the time of diagnosis, sex, family history of glaucoma, systemic hypertension, diabetes, Raynaud's phenomenon, migraine and myopia.

RESULTS

After multivariate analysis, older age at time of diagnosis (chi(2)(5) = 73.89, P < 0.001), myopia (odds ratio [OR] = 1.5, 95% confidence interval [CI] 1.0-2.2; P < 0.05), a family history of glaucoma (OR = 1.6, 95% CI 1.1-2.3; P < 0.01) and a high intraocular pressure (chi(2)(4) = 16.96; P = 0.002) were found to be more prevalent among those with POAG. No other significant differences could be found between the two groups.

CONCLUSION

Patients who have OHT may be at higher risk of developing POAG if they also have myopia, a family history of glaucoma or are of older age.

[Glaucoma and ocular hypertension in primary care]

OBJECTIVES

To find the distribution of intra-ocular pressure (IOP) in our population over 40 and the prevalence of glaucoma (G) and ocular hypertension (OH).

DESIGN

Descriptive.

SETTING

Primary care.

SUBJECTS

990 people >= 40 years old.Measurements. Age, sex, body mass index (BMI), ophthalmic history, risk factors, visual sharpness (optotype), ophthalmoscopy and IOP (applanation tonometry). Patients with back-of-eye disorders and/or IOP >= 21 mmHg were referred to the ophthalmologist for assessment (campimeter).

RESULTS

870 people, average age 54.66 and 45.4% of them men. Mean IOP was 12.96 in the right eye and 13.27 in the left, with significant differences between them, but not between sexes or age-groups. 70 patients were referred (11 for IOP >= 21, 54 for disturbance perceived by ophthalmoscope and 5 for both reasons). The ophthalmologist classified 9 as G, 12 as OH and 15 as suspected G. We calculated 1.81% (95% CI, 0.98-2.63) prevalence of G in the >= 40s, including 9 cases already known. OH prevalence was 1.61% (95% CI, 0.82-2.39). Through logistical regression, we found greater risk of G in people with myopia (OR adjusted for age and sex = 3.01) and Hypertriglyceridaemia (ORa, 6.34). OH risk was significantly greater in patients with BMI >= 30 (ORa, >= 4.20).

CONCLUSIONS

Glaucoma prevalence confirms published findings from other similar populations, while IOP and OH prevalence were much less here. Given that half G cases are undiagnosed, we believe its early detection in primary care should be highlighted, at least in at-risk groups.

Screening models for glaucoma

For social and economic reasons, glaucoma screening is a useful and necessary task, with possible benefits for individuals and the health care system arising from the early diagnosis and early therapy of patients with glaucoma. Early treatment of patients with glaucoma decreases the probability that those patients will become blind and lowers the direct and indirect costs for patients with glaucoma. Most of the reported studies dealing with glaucoma screening used only one parameter (eg, intraocular pressure) to detect and to discriminate glaucoma patients from healthy subjects. Glaucoma screening devices might be combined to obtain the best specificity and sensitivity. Because the diagnosis of glaucoma is very closely associated with a morphologic change in the optic nerve head, one screening parameter should be the morphology of the papilla. To increase specificity and sensitivity, a combination of morphologic and functional testing might be useful. In this review, we report the context of glaucoma screening in terms of health economics, the testing quality of devices for functional and morphologic screening, and the results of a pilot study.

Advanced glycation end products in human optic nerve head

AIMS

To localise advanced glycation end products (AGEs) in human optic nerve head.

METHODS

Optic nerve samples from 13 elderly individuals (seven diabetics and six non-diabetics) were obtained at necropsy. Pyrraline, an advanced glycation end product, was immunohistochemically localised in the optic nerve heads.

RESULTS

In the diabetic subjects, moderate to intense immunoreactivity for pyrraline was detected in sclera, pia mater, cribriform plates, connective tissues in the optic nerve, and around vessels in the optic nerve and pia mater. Immunoreactivity for pyrraline was also detected around retinal vessels. In the non-diabetic subjects, slight or no immunoreactivity for pyrraline was found in cribriform plates and around the optic nerve vessels.

CONCLUSION

Accumulation of AGEs in cribriform plates and around vessels in the optic nerve may contribute to the development of optic neuropathy in diabetic patients.

Glaucoma incidence in an unselected cohort of diabetic patients: is diabetes mellitus a risk factor for glaucoma? DARTS/MEMO collaboration. Diabetes Audit and Research in Tayside Study. Medicines Monitoring Unit

AIMS

To evaluate whether diabetes mellitus is a risk factor for the development of primary open angle glaucoma or ocular hypertension (OHT).

METHODS

A historical cohort study of an unselected population comprising all residents of the Tayside region of Scotland was performed using record linkage techniques followed by case note review. Ascertainment of prevalent diabetes was achieved using the Diabetes Audit and Research in Tayside Study (DARTS) validated regional diabetes register. Glaucoma and treated OHT were defined by encashment of community prescriptions and the statutory surgical procedure coding database.

RESULTS

The study population comprised 6631 diabetic subjects and 166 144 non-diabetic subjects aged >40 years without glaucoma or OHT at study entry. 65 patients with diabetes and 958 without diabetes were identified as new cases of glaucoma or treated OHT during the 24 month study period, yielding a standardised morbidity ratio of 127 (95% CI, 96-158). Case note review demonstrated non-differential misclassification of prevalent glaucoma and OHT as incident disease (diabetic cohort 20%, non-diabetic cohort 24%; p=0.56) primarily as a result of non-compliance in medically treated disease. Removing misclassified cases and adjusting for age yielded an incidence of primary open angle glaucoma in diabetes of 1.1/1000 patient years (95% CI, 0.89-1. 31) compared to 0.7/1000 patient years (95% CI, 0.54-0.86) in the non-diabetic cohort; RR 1.57 (95% CI, 0.99-2.48).

CONCLUSIONS

This study failed to confirm an association between diabetes mellitus and primary open angle glaucoma and ocular hypertension. A non-significant increase in diagnosed and treated disease in the diabetic population was observed, but evidence was also found that detection bias contributes to this association.