Medical vs surgical therapy in preventing visual field loss

Abstract

Lichter et al1Lichter P.R. Musch D.C. Gillespie B.W. et al.Interim clinical outcomes in the Collaborative Initial Glaucoma Treatment Study (CIGTS) comparing initial treatment randomized to medications or surgery.Ophthalmology. 2001; 108: 1943-1953Abstract Full Text Full Text PDF PubMed Scopus (910) Google Scholar presented a detailed analysis of their work regarding the initial management of glaucoma in the Collaborative Initial Glaucoma Treatment Study (CIGTS). Closer inspection of their data provides additional insightful information that may be beneficial in the management of glaucoma, particularly when supplemented by information gained from the Advanced Glaucoma Intervention Study (AGIS)2The AGIS InvestigatorsThe Advanced Glaucoma Intervention Study (AGIS) 7. The relationship between control of intraocular pressure and visual field deterioration.Am J Ophthalmol. 2000; 130: 429-440Abstract Full Text Full Text PDF PubMed Scopus (2269) Google Scholar, 3The AGIS InvestigatorsThe Advanced Glaucoma Intervention Study (AGIS) 9. Comparison of glaucoma outcomes in black and white patients within treatment groups.Am J Ophthalmol. 2001; 132: 311-320Abstract Full Text Full Text PDF PubMed Scopus (104) Google Scholar, 4The AGIS InvestigatorsThe Advanced Glaucoma Intervention Study (AGIS) 4. Comparison of treatment outcomes within race.Ophthalmology. 1998; 105: 1146-1164Abstract Full Text Full Text PDF PubMed Scopus (195) Google Scholar and the Glaucoma Laser Trial (GLT).5Glaucoma Laser Trial Research GroupThe Glaucoma Laser Trial (GLT) 2. Results of argon laser trabeculoplasty versus topical medicines.Ophthalmology. 1990; 97: 1403-1413Abstract Full Text PDF PubMed Scopus (208) Google Scholar, 6Glaucoma Laser Trial Research GroupThe Glaucoma Laser Trial (GLT) and Glaucoma Laser Trial Follow-up Study 7. Results.Am J Ophthalmol. 1995; 120: 718-731Abstract Full Text PDF PubMed Google Scholar From these studies, the following can be gleaned: 1.The first-year failure rates are moderately high, while subsequent years’ failure rates are low—failure being defined as not achieving target intraocular pressure of 30% or more reduction from baseline, or less than 18 mmHg.2.The first year failure rate for trabeculectomy only was 12% and topical medications only was 24%. Subsequent years’ failure rate for trabeculectomy only was 3% per year, which was slightly higher than topical medications only at 1% to 2% per year.3.In contrast to topical medications only or trabeculectomy only, argon laser trabeculoplasty (ALT) only — not combined with medications—has a very high failure rate at 37% in the first year, 56% by 2 years, and 80% within a median of 3 years.5Glaucoma Laser Trial Research GroupThe Glaucoma Laser Trial (GLT) 2. Results of argon laser trabeculoplasty versus topical medicines.Ophthalmology. 1990; 97: 1403-1413Abstract Full Text PDF PubMed Scopus (208) Google Scholar, 6Glaucoma Laser Trial Research GroupThe Glaucoma Laser Trial (GLT) and Glaucoma Laser Trial Follow-up Study 7. Results.Am J Ophthalmol. 1995; 120: 718-731Abstract Full Text PDF PubMed Google Scholar4.The failure rates of trabeculectomy and ALT are reduced when topical antiglaucoma medications are used in combination with these therapies.5.The first-year failure rate for trabeculectomy only decreased to approximately 7% (from 12%) when topical antiglaucoma medications are used. Likewise, the first year failure rate for ALT only decreased to approximately 16% (from 37%) when topical antiglaucoma medications are used.6.The 4-year cumulative failure rate for ALT, when performed after trabeculectomy only (i.e., proportion of eyes in the surgery group that failed ALT thus necessitating a second trabeculectomy) appears to be very high (ranging from 38%-100%), when topical antiglaucoma medications have not been instituted.7.Although initial surgery resulted in almost a 50% lower failure rate in the first year compared with topical medications only, the potential increase in visual acuity loss and changes in quality-of-life indicators7Janz N.K. Wren P.A. Lichter P.R. et al.The Collaborative Initial Glaucoma Treatment Study (CIGTS). Interim quality of life findings after initial medical or surgical treatment of glaucoma.Ophthalmology. 2001; 108: 1954-1965Abstract Full Text Full Text PDF PubMed Scopus (168) Google Scholar may suggest that “aggressive” medical therapy followed by ALT may be the preferred sequence, at least for black patients. (Note that for white patients in the AGIS,3The AGIS InvestigatorsThe Advanced Glaucoma Intervention Study (AGIS) 9. Comparison of glaucoma outcomes in black and white patients within treatment groups.Am J Ophthalmol. 2001; 132: 311-320Abstract Full Text Full Text PDF PubMed Scopus (104) Google Scholar, 4The AGIS InvestigatorsThe Advanced Glaucoma Intervention Study (AGIS) 4. Comparison of treatment outcomes within race.Ophthalmology. 1998; 105: 1146-1164Abstract Full Text Full Text PDF PubMed Scopus (195) Google Scholar this sequence of topical medications → ALT → trabeculectomy was more beneficial in the first 4 years.) Since the principles above were generated by extrapolating data from the studies, it would be helpful if the authors of the CIGTS could provide actual calculated data that would either support or refute the above statements. Additionally, a cost–benefit analysis should be helpful in resolving the above issue, although this may require another in-depth study. Finally, it is understood that the authors may not wish to comment on data generated strictly from the AGIS or GLT studies, despite data from these studies being germane to the treatment of glaucoma.