RESUMO
In 2020, the global prevalence of glaucoma was estimated to be 76 million and it was projected to increase to 111.8 million by 2040. Accurate intraocular pressure (IOP) measurement is imperative in glaucoma management since it is the only modifiable risk factor. Numerous studies have compared the reliability of IOP measured using transpalpebral tonometers and Goldmann applanation tonometry (GAT). This systematic review and meta-analysis aims to update the existing literature with a reliability and agreement comparison of transpalpebral tonometers against the gold standard GAT for IOP measurement among individuals presenting for ophthalmic examinations. The data collection will be performed using a predefined search strategy through electronic databases. Prospective methods-comparison studies published between January 2000 and September 2022 will be included. Studies will be deemed eligible if they report empirical findings on the agreement between transpalpebral tonometry and Goldmann applanation tonometry. The standard deviation and limits of agreement between each study and their pooled estimate along with weights and percentage of error will be reported using a forest plot. Cochrane’s Q test and the I2 statistic will be used to assess heterogeneity, and the publication bias will be investigated using a funnel plot, Begg’s and Egger’s tests. The review results will provide additional evidence on the reliability of transpalpebral tonometers that, in turn, could possibly assist practitioners to make informed decision about using it as a screening or diagnostic device for clinical practice, outreach camps, or home-based screening. Institutional Ethics Committee registration number: RET202200390. PROSPERO Registration Number: CRD42022321693.
RESUMO
Primary open angle glaucoma (POAG) is the most common form of glaucoma and the second leading cause of blindness in the world. Discovery of the candidate gene MYOC (TIGR/MYOC) encoding the protein myocilin, believed to have a role in cytoskeletal function, might play a key role in understanding the pathogenesis of POAG. MYOC is expressed in many ocular tissues, including trabecular meshwork (TM), a specialised eye tissue essential in regulating intraocular pressure (IOP). Later it was shown to be the trabecular meshwork inducible-glucocorticoid response protein (TIGR). Mutations in MYOC have been identified as the cause of hereditary juvenile-onset open-angle glaucoma (JOAG). The unprocessed myocilin with signal peptide is a 55-kDa protein with 504 amino acids. Mature myocilin is known to form multimers. Wild type myocilin protein is normally secreted into the trabecular extracellular matrix (ECM) and there appears to interact with various ECM materials. It is believed that the deposition of high amounts of myocilin in trabecular ECM could affect aqueous outflow either by physical barrier and/or through cell-mediated process leading to elevation of IOP. The N-terminal region of the myocilin has sequence similarity to myosin (muscle protein) and the C-terminal of the protein has an olfactomedin-like domain. Structural and genetic studies of the MYOC gene and its protein product along with molecular modeling could lead to better understanding of the pathogenesis of POAG. This review highlights the current understanding of myocilin and the relevance of genetic and structural work.