Eyes with advanced glaucoma have little residual reserve and small amounts of progression have important consequences affecting a patient's visual function and quality of life. Investigation of risk factors for further deterioration of functional damage in these patients is of clinical importance. This is especially true for changes in central vision as studies have shown that the visual field (VF) close to the fixation1,2 is more strongly associated with quality of life in glaucoma patients. However, information on the risk factors for further deterioration of central visual function in a large cohort of patients with advanced glaucoma is relatively scarce.
Sugisaki et al. published the results of a five-year prospective, observational study to identify risk factors for further deterioration of visual function in patients with advanced glaucoma whose IOP was clinically well controlled, paying particular attention to the changes in the central 10-2 VF. At baseline, all the patients had best corrected visual acuity (BCVA) of better than 20/40 and 24-2 VF of worse than -20 dB. Deterioration of 10-2 VF was defined by the presence of the same 3 3 points with negative total deviation slope -1 dB/year at P < 0.01 on ≥ 3 consecutive tests, deterioration of HFA 24-2 results by an increase ≥ 2 in the Advanced Glaucoma Intervention Study score on ≥ 2 consecutive tests, and deterioration of BCVA by an increase of 3 0.2 logarithm of the minimum angle of resolution (logMAR) on ≥ 2 consecutive tests.
A total of 175 eyes of 175 patients with a mean 24-2 VF and 10-2 VF of- 25.9 and -22.9 dB, respectively, were included. After five years, lower BCVA at baseline was associated significantly with further deterioration of 10-2 VF. Greater β-peripapillary atrophy (β- PPA) area-to-disc area ratio, use of systemic antihypertensive agents and lower BCVA were associated significantly with further deterioration of BCVA.
Interestingly, although the mean IOP during follow-up was 13.0 mmHg over the course of five years, 26.9% of the eyes showed deterioration of VF within the central 10, and 19.4% of the eyes showed VA deterioration attributable to glaucoma progression, which resulted in blindness in 4.6% of eyes. The use of systemic antihypertensive agents and lower diastolic blood pressure were risk factors for further VA or 10-2 VF deterioration in advanced glaucoma in the current report, which in consistent with prior studies that reported compromised local circulation as an important prognostic factor for central visual function in advanced glaucoma.3,4
There are some limitations to this study. It should be noted that these results would not be applicable to eyes with advanced glaucoma whose VA was impaired to worse than 20/40 because of glaucomatous damage. Also, the mean IOP of Japanese population is lower than many other ethnic groups. In fact, despite the low mean IOP in this study, only 13 eyes from this cohort had undergone trabeculectomy, which shows that the results might not generalizable to other ethnicities. Finally, the eyes in this cohort were very advanced with a mean 24-2 VF of worse than -25 dB. At this level, visual fields have a significant amount of variability and this limits the ability to detect progression.5 However, the specificity of the criteria they used was sufficiently high (99.99%) for the simulated stable HFA 10-2 VF series of eyes with advanced glaucoma.
Greater β-PPA area-to-disc ratio and lower BCVA could be used as simple prognostic factors for the central VA of eyes with advanced glaucoma
Overall, the present study suggests that greater β-PPA area-to-disc ratio and lower BCVA could be used as simple prognostic factors for the central VA of eyes with advanced glaucoma and that a medical history of hypertension should also be considered in the management of advanced glaucoma.