Patricia Nelson

A Comparison of Ocular Blood Flow in Untreated Primary Open-angle Glaucoma and Ocular Hypertension

PURPOSE To compare ocular blood flow in untreated primary open-angle glaucoma and ocular hypertension using scanning laser Doppler flowmetry and pulsatile ocular blood flow. METHOD Fourteen ocular hypertensive subjects and 10 patients with primary open-angle glaucoma were matched for intraocular pressure, mean arterial blood pressure, and age. They had scanning laser Doppler flowmetry images taken centered on the optic disk. Pulsatile ocular blood flow readings were performed in sitting, standing, and supine positions. No subjects were receiving topical antiglaucoma treatment, systemic beta-blockers, calcium antagonists, or nitrates at the time of measurement. RESULTS Laser Doppler flowmetry results showed a significant reduction in blood velocity, volume, and flow at the lamina cribrosa and the temporal neuroretinal rim in glaucoma compared to ocular hypertension (P < .05). No difference was found between the groups at the nasal neuroretinal rim or the nasal juxtapapillary retina. There was a significant increase in minimum velocity (P = .03) at the temporal juxtapapillary retina in glaucoma compared to ocular hypertension. The ocular pulse amplitude, pulse volume, and pulsatile ocular blood flow were significantly lower (P < .05) in the glaucoma group compared to ocular hypertension in sitting and standing positions. CONCLUSION Having controlled for factors known to affect perfusion pressure, we found evidence of reduced ocular blood flow in primary open-angle glaucoma compared with ocular hypertension. Our findings indicate a reduction in choroidal and short posterior ciliary artery circulation in primary open-angle glaucoma. Whether these changes in blood flow are a cause or a consequence of glaucomatous optic atrophy is still unknown.

Patients' perception of visual impairment in glaucoma: a pilot study.

BACKGROUND/AIMS There is a paucity of useful information on the level of visual disability suffered by glaucoma patients. The aims of this study were to determine and rank the frequency of self reported visual disability in daily tasks performed by glaucoma patients; to examine the interrelation between disabilities using factor analysis; to study the relation between perceived visual difficulty and a measure of the severity of visual field loss; to develop a glaucoma specific subgroup of questions; and examine the validity and reliability of this subgroup of questions. METHODS 63 glaucoma patients completed a questionnaire containing 62 questions covering 10 broad aspects of daily life activities using a five point answer scale. Patients were classified into three groups as having mild, moderate, and severe field loss on the basis of the perimetric results. The relation between a measure of the severity of visual field loss and subjective visual disability in the three groups was examined. RESULTS Using factor analysis, the most frequently reported problems were grouped into the following four categories: outdoor mobility, glare and lighting conditions and activities demanding functional peripheral vision, household tasks, and personal care. These four factors accounted for 72% of the variability in the patients’ questionnaire responses. With increasing severity of binocular visual field loss there was an increase in the number of self reported visual problems. A loss of confidence in performing some routine daily tasks tended to precede self reported specific visual disabilities. The factor “glare and lighting and activities demanding functional peripheral vision” was found to have a significant relation with a measure of visual field loss and was used to create a glaucoma specific subset of questions. Cronbach’s α showed a high degree of reliability and internal consistency (α =0.96) in this glaucoma specific subset of questions. Furthermore, the validity of this new subset of questions was shown to be significant (r=0.037, p<0.05) for the correlation between a measure of the severity of binocular visual field loss and the mean score of the variables used in the glaucoma specific subgroup of questions. CONCLUSIONS Outcome measures and quality of life issues need to be addressed in glaucoma. This pilot study identified common problems encountered by patients which at the present time are not assessed in routine glaucoma care. It also identified a subgroup of questions that seems to be specific for glaucoma. Further research is required if a significant impact on the quality of life of glaucoma patients is to be achieved.