Primary open angle glaucoma

Patients with ocular hypertension or primary open-angle glaucoma typically have a slow, insidious loss of vision. This is contrasted by the course of acute primary angle-closure glaucoma which can lead to rapid vision loss that develops over hours to days. 

Since primary open-angle glaucoma is a chronic, often asymptomatic condition, the decision of when and how to treat... 

Clinical Presentation of Primary Open-Angle Glaucoma ... 

PACG primary angle-closure glaucoma POAG primary open-angle glaucoma... 

American Academy of Ophthalmology Glaucoma Panel. Primary Open Angle. San Francisco American Academy of Ophthalmology, 2005. 

Tripathi RC, Tripathi BJ, Haggerty C. Drug-induced glaucomas mechanism and management. Drug Saf 2003 26 749-767. Weinreb RN, Khaw PT. Primary open-angle glaucoma. Lancet 2004 363 1711-1720. 

POAG Primary open-angle glaucoma RR Respiratory rate recovery room... 

The 5 groups of agents used in therapy of primary open-angle glaucoma are listed in the table, which summarizes their mechanism of decreasing lOP, effects on pupil size and ciliary muscle and duration of action. 

There are several types of -class CAs i.e., a-CA I-VII, reported in the literature, out of which the human carbonic anhydrase II (HCA II), the most extensively studied carbonic anhydrase, has an exceptionally high CO2 hydration rate and a wide tissue distribution 107). The HCA II comprises a single polypeptide chain with a molecular mass of 29.3 kDa and contains one catalytic zinc ion, coordinated to three histidine residues, His 94, His 96, and His 119. A tetrahedral coordination geometry around the metal center is completed with a water molecule, which forms a hydroxide ion with a pK value of 7.0 108). Quigley and co-workers 109,110) reported that the inhibition of the synthesis of HCO3 from CO2 and OH- reduces aqueous humor formation and lowers intra-ocular pressure, which is a major risk factor for primary open-angle glaucoma. 

Patel SS, Spencer CM. Latanoprost. A review of its pharmacological properties, clinical efficacy and tolerability in the management of primary open-angle glaucoma and ocular hypertension. Drugs Aging 1996 9(5) 363-78. 

Ekatomatis P. Herpes simplex dendritic keratitis after treatment with latanoprost for primary open angle glaucoma. Br J Ophthalmol 2001 85(8) 1008-9. 

The effects of latanoprost on iris structure were assessed in 17 patients with bilateral primary open-angle glaucoma. In each case an iridectomy was performed in one eye, which served as a control. The other eye was then treated with latanoprost for 6 months followed by iridectomy. Light and electronic microscopy showed no evidence of early ultrastructural changes in the latano-prost-treated eyes (14). 

Of 17 patients requiring filtering surgery for primary open-angle glaucoma randomized to receive latanoprost (n = 8) or alternative medications (n = 9) for 3 months before surgery, all had peripheral iridectomy specimens,... 

A 34-year-old woman with primary open-angle glaucoma began topical application of travoprost ophthalmic solution (0.004%, 1 drop/day) and 30 minutes later developed abdominal cramp that lasted for 2 hours. The same symptoms appeared on 3 days after drug administration. The pain disappeared after travoprost withdrawal. 

TAC of lacrimal fluid decreased with the progress of primary open-angle glaucoma. Blood plasma TAC decreased significantly in the third far-advanced stage. A course of total antioxidant vitamin therapy normalized plasma TAC even in patients with far-advanced glaucoma, whereas the lacrimal TAC did not normalize (M4). 

M4. Makashova, N. V., Babenkova, I. V., and Teselkin, I. O., The antioxidant activity of the lacrimal fluid in patients with primary open-angle glaucoma. Vestn. Oftalmol. 115,3-4 (1999). 

Primary open-angle glaucoma is a very common form (also known as chronic simple or wide-angle glaucoma). It results from obstruction in the trabecular meshwork which acts as the drainage system for the aqueous humour. 

A beta-blocker may be used in the treatment of primary open-angle glaucoma, but these drugs are contraindicated for use in persons with chronic obstructive pulmonary disease and heart block (see Chapter 10). A careful history should be taken before initiating therapy to avoid potentially fatal ramifications. It is advisable to monitor patients who are taking beta-blockers (e.g., pulse, blood pressure) and to inquire about side effects at periodic follow-up examinations. 

Topically applied cyclopentolate can increase lOP in patients with primary open-angle glaucoma, and it may precipitate an attack of acute glaucoma in patients with narrow angles. It was reported that approximately 1 of 4 eyes with open-angle glaucoma responded to topical 1% cyclopentolate with a significant elevation of lOP (6 mm Hg or more increase compared with the baseline lOP), whereas only 2 of 100 normal eyes responded in a similar manner. These two apparently normal eyes also responded with an lOP increase of 6 mm Hg or more with the application of 5% homatropine or an application of 1% atropine. 

Brimonidine s efficacy has been compared with that of prostaglandin analogues, topical CAIs, and P-blockers. Results in patients with glaucoma and ocular hypertension indicate that the peak ocnlar hypotensive effect of 0.2% brimonidine is comparable with that of 0.5% timolol (Figure 10-11). When dosed twice daily, 0.2% brimonidine is less effective than latanoprost 0.005% administered once daily. Brimonidine 0.15% with Purite is similar to dorzolamide 2% when used twice daily fc>r treatment of primary open-angle glaucoma or ocular hypertension. 

Studies have suggested that brimonidine 0.15% with Purite and dorzolamide 2%, each added to latanoprost, have similar ocular hypotensive efficacy in patients with primary open-angle glaucoma or ocular hypertension (Figure 10-12). Moreover, the combination of brimonidine 0.2% and latanoprost 0.005% provides lOP control superior to that of the fixed combination of... 

Figure 10-15 Mean intraocular pressure (lOP) change (mm Hg) for the various treatment groups by visit and time of day for a 3-month treatment period. Each value represents the least-squares mean of the change from baseline diurnal lOP, and all were significant. (Adapted from Silver LH, Brinzolamide Primary Therapy Smdy Group. Clinical efficacy and safety of brinzolamide [Azopt], a new topical carbonic anhydrase inhibitor for primary open-angle glaucoma and ocular hypertension. Am J Ophthalmol 1998 126 400-408.)...

In addition, most eyes with primary open-angle glaucoma treated with pilocarpine demonstrate narrowing of the anterior chamber angle and thickening of the crystalline lens after each instillation of the drug. 

Since its introduction into clinical practice in 1876, pilocarpine has remained the most usefiil miotic for management of primary open-angle glaucoma, acute angle-closure glaucoma, and many secondary glaucomas. Pilocarpine is commercially arailable as an ophthalmic solution in concentrations from 0.25% to 10% (see Table 10-7). Pilocarpine is also commercially available as a 4% ophthalmic gel that is supplied in 3 5-g tubes. 

---