OBJECTIVE: To observe for any correlation existing between the decreasing values of central corneal thickness and worsening of the field defect in primary open angle glaucoma and Whether Pachymetry value of an eye may decide the intensity of the treatment needed for that eye.
METERIALS & METHODS: Observational cross sectional study on 225 eyes of 119 diagnosed POAG patients with reliable fields and age range of 30 yrs to 80 yrs and refractive error between ±5 D sph and ±3 D cyl with no h/o corneal pathology or corneal or intraocular surgery. All patients underwent below mentioned clinical examination at the same visit: BCVA, Slit lamp exam, Applanation tonometry, Gonioscopy, Dilated fundus examination and stereoscopic examination of the optic disc and nerve fiber layer, white on white visual fields- 24-2 programme, Pachymetry: Sample was divided into three groups according to-1- Mean deviation (MD) values: Mild damage group- MD better than -6db, Moderate damage group- MD between -6db and -12db, Severe damage group- MD worse than -12db.:& 2- Central corneal thickness: Thinner corneas- ≤520µ, Adequate corneas- >520µ & ≤555µ, Thicker corneas- >555µ. One-way analysis of variance, test was performed to find out the correlation of severity of primary open angle glaucoma with central corneal thickness. 2 tailed Pearson correlation test was used to find out the existence of any equation between Central Corneal thickness and worsening of Mean deviation values.
RESULTS: Significant association of severe disease with thin cornea (P= 0.021), A significant finding of Central CornealThickening as MD worsens was found in mild damage group only (Pearson correlation factor= -0.250, P= 0.024), All thin corneas are not associated with severe disease, None of the severity indicators of the disease correlated with decreasing corneal thickness, Sudden dip in CCT and worsening of the disease in 7th decade.
CONCLUSION: Corneal thickness in glaucomatous patients could be a kinetic process,increasing CCT means progressive disease and pressures not adequately controlled and thinning means the tisue has given up under the stress of increased pressures and disease will progreess ferrociouly thus needing tight control on IOP in the form of surgical intervention. hence periodic CCT measurements are mandatory
Posted by: Pankhuri Johari, pivate practitioner, sri ram janaki netralya, India (01-Nov-2011)