AIM: To evaluate the relationship between central corneal thickness and intraocular pressure in healthy and glaucomatous eyes of adults. To make up to date summary of the results of studies done on the association of central corneal thickness measurements and intraocular pressure measurements in Glaucoma patients and in healthy subject.

METHODS: To identify relevant studies a search of MEDLINE and Science Direct databases for studies investigating the relationship between central corneal thickness(CCT)and intraocular pressure(IOP)was conducted. The Search period was from Sep. 10^th to Oct. 28^th of 2015. Search key words included: central corneal thickness, intraocular pressure, glaucoma, ocular hypertension, exfoliative glaucoma, applanation tonometry, pachymetry, primary open angle glaucoma, Goldmann applanation tonometry. In addition, a manual search of “The Year Book of Ophthalmology” Journals 2004 to 2006 Issues in the Southern Medical University Library English language section was done. The following exclusion criteria applied: 1)non-English media studies; 2)studies done before 2005; 3)case series and case reviews; 4)studies involving treatment protocols or surgical techniques; 5)studies comparing glaucomatous eyes with other conditions such as diabetes, hypertension or cardiovascular disease as secondary variables; 6)studies with children as study subjects; 7)studies with animal subjects.

RESULTS: There were 12 observational studies and 1 case control study included. Compared to control subjects, patients had significantly increased IOP(SMD: 0.50, 95% CI: 0.30～0.70, Z=4.88, P<0.001). Compared to control subjects, patients had significantly decreased CCT levels(SMD: -0.14, 95% CI: -0.23～-0.05, Z=3.14, P=0.002). Meta-regression revealed that mean-age(P=0.025)was found to have a statistically significant relation to the observed CCT difference between glaucomatous eyes and controls.

CONCLUSION: It has been established that glaucomatous eyes tend to have thinner CCT and higher IOP compared to normal eyes.