Ocular risk factors for progression of primary open angle glaucoma in the Tunisian population

Purpose. - To evaluate intraocular pressure parameters and the role of other ocular risk factors in the progression of primary open angle glaucoma. Patients and methods. - We performed a retrospective analysis of long-term glaucomatous progression in 140 patients (280 eyes) with primary open angle glaucoma (POAG) between 1998 and 2009. After analyzing their disease progression, the eyes of our patients were divided into two groups: group 1 (G1) consisted of eyes with worsening of their POAG, and group 2 (G2) consisted of the eyes that remained stable. The indicators of progression studied were factors associated with glaucomatous optic neuropathy, other ocular risk factors, and treatment-related risk factors. Results. - We found 188 eyes with stable visual fields (G2) and 92 eyes with glaucoma progression (G1), for a progression rate of 32.9%. Mean intraocular pressure (IOP) at diagnosis was statistically higher in the cases with progression, 22.78 mmHg vs. 19.9 mmHg for stable cases (P = 0.03; OR = 5.25). Higher final intraocular pressure (IOP) was also associated with progression (16.82 mmHg for G1 vs. 14.85 mmHg for G2; P = 0.051). IOP less or equal to 12.75 mmHg was identified as the target pressure for our population. Progressed eyes also showed a statistically higher diurnal peak IOP (23.13 mmHg vs. 19.87 mmHg for G2; P = 0.007). Long term IOP fluctuation was also predictive of progression (4.43 mmHg for G1 vs. 2.31 mmHg for G2; P = 0.003). Eyes with initial visual field defect more than 8.2 dB had 4.8 times the risk of progression (P = 0.07). However, eyes diagnosed in an early glaucoma stage had four times the chance of maintaining a stable visual field (P = 0.003). Statistically significant risk factors between the two groups also included: pseudoexfoliation (OR = 2.84; P = 0.05), cornea less than 505 mu (OR = 10.89; P = 0.005), topical beta blockers (P = 0.003), and more than two topical medications (OR = 3; P = 0.003). Conclusion. - It is currently known that IOP lowering contributes to glaucoma stabilization. However, this single criterion remains insufficient, as other, particularly ocular, factors have been implicated in glaucoma progression. Identification of these risk factors allows for a better therapeutic approach toward these patients, so as to preserve their vision and quality of life. (C) 2012 Published by Elsevier Masson SAS.