Ageing
Henry J. Woodford in Essential Geriatrics, 2022
Glaucoma typically causes a loss of peripheral vision or visual field defects (scotomas). It is related to reduced aqueous humour outflow that results in an increased intraocular pressure (> 21 mmHg). Primary open-angle glaucoma is an insidious disease caused by a blockage of flow in the trabecular meshwork, which results in gradual damage to the optic nerve. A large cup to disc ratio is seen on ophthalmoscopy. It is usually managed initially with eye drops, such as prostaglandin analogues (e.g. latanoprost) or beta-blockers (e.g. timolol). Secondary treatments include acetazolamide, sympathomimetics (e.g. brimonidine eye drops) and surgical iridectomy. Primary angle-closure glaucoma is caused by blockage of flow into the anterior chamber. It causes an acute red-eye and should be urgently referred to an ophthalmologist.
Dual Customized U-Net-based Automated Diagnosis of Glaucoma
K. Gayathri Devi, Kishore Balasubramanian, Le Anh Ngoc in Machine Learning and Deep Learning Techniques for Medical Science, 2022
The CDR (Cup to Disc Ratio) value is calculated using the optic disc and optic cup diameters discovered by computing the diameters of the segmentation masks provided by our suggested method. Vertical diameters and horizontal diameters of the cup and disc are used to generate the vertical and horizontal CDR. The mean value of the vertical and horizontal CDR is computed and if this value is less than 0.5, it means that the person whose retinal fundus image generated this CDR is not having glaucoma. If CDR is greater than 0.5, then the person is suffering from glaucoma. The final glaucoma results of a few of the test set images are given in Table 13.9. The severity of glaucoma is diagnosed as Yes and its absence is diagnosed as No in the tabulated results.
Neurologic Diagnosis
Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw in Hankey's Clinical Neurology, 2020
Optic disc: note its color. It will be pale in optic atrophy, and pink and congested in papilledema where dilated veins and adjacent retinal hemorrhages are often present due to raised intracranial pressure (ICP) (Figure 1.14): Optic cup: cup/disc ratio size 0.1–0.3 is diminished in papilledema and enlarged in glaucoma.Spontaneous venous pulsation as the vein enters the disc or disc margin. Identifying venous pulsations is worthwhile, as if they are present, raised ICP is unlikely. However, pulsation is absent in 20% of the normal population.Disc margins: blurred in papilledema or by “bubbles” of optic nerve head drusen (benign). Drusen buried in the optic nerve head may be a cause of anxiety as “pseudopapilledema” (Figures 1.15, 1.16).As the optic nerve head is often calcified, this can be confirmed on thin-slice computed tomography (CT) head scan (see Figure 1.16) or orbital ultrasound.Other causes of optic nerve head swelling include anterior optic neuropathies (inflammatory, ischemic, infiltrative, and compressive) as well as ocular disease.
Retinal and Choroidal Changes in Patients with Parkinson’s Disease Detected by Swept-Source Optical Coherence Tomography
Published in Current Eye Research, 2018
Maria Satue, Javier Obis, Raquel Alarcia, Elvira Orduna, Maria J Rodrigo, Elisa Vilades, Hector Gracia, Sofia Otin, Maria I Fuertes, Vicente Polo, Jose M Larrosa, Luis E Pablo, Elena Garcia-Martin
Another possible bias is that subclinical glaucomatous eyes might have been included in the study despite the fact that all participants (PD and controls) were evaluated for IOP levels and optic disc glaucomatous changes by funduscopy using a 78D lens (but not for glaucomatous changes in perimetry). It is possible that both groups of subjects contained subclinical glaucomatous eyes, especially the Parkinson group since these patients may have an increased occurrence rate of glaucoma (based on glaucomatous perimetry changes and high cup to disc ratio). Despite normal tension glaucoma being difficult to detect, we believe evaluation of the cup to disc ratio in our patients by an experienced examiner decreased (although did not eliminate completely) the chances of glaucomatous damage being included in the study.
Validity of code based algorithms to identify primary open angle glaucoma (POAG) in Veterans Affairs (VA) administrative databases
Published in Ophthalmic Epidemiology, 2018
K. S. Biggerstaff, B. J. Frankfort, S. Orengo-Nania, J. Garcia, E. Chiao, J. R. Kramer, D. White
A panel of three glaucoma trained ophthalmologists chose to define the gold standard definition of glaucoma in this study as any eye with a cup to disc ratio ≥ 0.6, as indicated in the literature that when this criteria is met the probability of abnormality increases dramatically and is indicative of glaucomatous risk across all racial group in the United States.12,13 Our gold standard definition also included a cup to disc ratio difference of ≥ 0.2 between right and left eyes because 88% of normal subjects have a cup to disc ratio difference equal or less than 0.114 A recent meta-analysis showed that the likelihood ratio of detecting primary open angle glaucoma by using a cup to disc ratio ≥ 0.6 was 7.0–7.5, and for using asymmetry ≥ 0.2 the likelihood ratio was 3.9–4.115 These likelihood ratio levels thus demonstrate that their inclusion in diagnostic test criteria is associated with a moderate to large increase in post-test probability that a patient had clinically confirmed glaucoma. There have been other published studies in peer reviewed journals, which have used similar criteria to this.16,17 Even in patients with ocular hypertension, without glaucoma, increased cup to disc ratio and cup to disc asymmetry has been shown to correlate with increased risk for development of glaucoma.18,19
The haplotype of the CDKN2B-AS1 gene is associated with primary open-angle glaucoma and pseudoexfoliation glaucoma in the Caucasian population of Central Russia
Published in Ophthalmic Genetics, 2021
Natalya Eliseeva, Irina Ponomarenko, Evgeny Reshetnikov, Volodymyr Dvornyk, Mikhail Churnosov
Genetic factors have been suggested as important contributors to the pathogenesis of glaucoma (6,7). Recent genome-wide association studies (GWASs) identified several genetic polymorphisms associated with POAG, including cyclin-dependent kinase inhibitor 2B antisense noncoding RNA (CDKN2B-AS1) genomic region on chromosome 9p21.3 (8–14). Additionally, chromosome 9p21.3, where the CDKN2B-AS1 gene is located, has been identified by GWASs as an important susceptibility locus for optic disc characteristics (optic cup area, vertical cup-disc ratio) (15–18). The cup-disc ratio and optic cup area are the structural features of the optic nerve strongly correlated with glaucoma development (19).
Related Knowledge Centers
- Glaucoma
- Intraocular Pressure
- Optic Disc
- Ophthalmology
- Optometry