Continuing study by the Collabor-ative Normal-tension Glaucoma Study Group suggests that different factors such as disk hemorrhage, gender, migraine and family history of disease may contribute to glaucomatous optic neuropathy in different cases of normal-tension glaucoma. Any of these factors interact with intraocular pressure to different degrees and thereby affect the magnitude of the benefit of IOP lowering.

Researchers analyzed visual field data from 144 subjects (144 eyes) randomized to two groups: those not receiving IOP-lowering treatments or those having IOP lowered by 30 percent. Survival analyses were applied to compare times to progression between groups. Changes in mean deviation over time were compared with multilevel random-effects models.
In this randomized clinical trial with secondary analysis, the most readily demonstrated treatment benefit occurred in patients with the characteristics listed in the sidebar above.

IOP lowering benefited females with mi-graine (P < .05), but researchers did not note the elimination of all migraine-associated risk.

Researchers say that some findings of this study are only suggestive and may best be taken as hints for further investigation.

(Am J Ophthalmol 2003;136:820-829)
Anderson D, Drance S, and Schulzer M for the Collaborative Normal-tension Glaucoma Study Group

The Effects of Soft Lenses
Turkish researchers recommend carefully monitoring tear-film breakup time and Schirmer test results in contact-lens wearers. They found that contact lenses cause an increase in the proportion of tear film mucus, a decrease in TBUT and a decrease in the basal Schirmer test result. If this condition is continued for a long time, researchers propose, it may cause damage to the conjunctival epithelium and lead to a vicious cycle and dry-eye syndrome.

They evaluated 100 eyes of 50 soft contact lens wearers and 80 eyes of 40 subjects in a control group. Contact-lens wearers were divided into three groups according to duration of soft CL use: Group A (0 to 12 months; 15 cases), Group B (13 to 48 months; 21 cases), and Group C (longer than 48 months; 14 cases).

When these groups were evaluated according to the Nelson grading method, 21 percent of cases were grade 0; 32 percent were grade 1; and 28 percent were grade 3. (Nelson classification is used for analysis of the cell morphology and density of goblet cells. Greater changes indicate greater epithelial stress.) They found statistically significant differences in epithelial cell morphology, goblet cell density, snakelike chromatin changes, TFBUT and basal Schirmer test results between the control and study groups.
(Eye & Contact Lens, 2003;29:230-233)
Söker Çakmak S, Kaan Ünlü M, Karaca C, Nergiz Y, and Ìpek S