Strong associations between keratoconus and several conditions of autoimmune diseases and allergic immune disorders may point to the role of the immune system in the pathogenesis of keratoconus, suggests a new study from the Meir Hospital, Sapir Medical Center in Kfar-Saba, Israel. The seven-year, retrospective, observational case-control study included all the members in the Central District of Clalit Health Services in Israel who were diagnosed to have keratoconus (n=426) and 1,704 age- and gender-matched controls. The authors calculated the prevalence of rheumatoid arthritis, ulcerative colitis, arthropathy, amyloidosis, systemic lupus erythematosus, celiac disease, multiple sclerosis, myasthenia gravis, polymyalgia rheumatica, idiopathic thrombocytopenic purpura, Crohn's disease, Hashimoto thyroiditis, autoimmune hepatitis, irritable bowel syndrome, asthma and environmental allergy. The odds ratio of having immune disorders among patients with keratoconus was compared with controls.

The association between keratoconus and the following disorders was statistically significant: rheumatoid arthritis (OR=8.1; 95-percent confidence interval: 1.5 to 44.2), ulcerative colitis (OR=12.1; CI: 1.3 to 116), autoimmune chronic active hepatitis (OR=6; CI: 1.01 to 36), Hashimoto thyroiditis (OR=2; CI: 1.2 to 3.3), arthropathy (OR=1.4; CI: 1.1 to 1.8), asthma (OR=2.1; CI: 1.4 to 3.2), environmental allergy (OR=1.3; CI: 1.02 to 1.75) and irritable bowel syndrome (OR=5; CI: 2.1 to 12.1). Multiple sclerosis (OR=2; CI: 0.2 to 22) and Crohn's disease (OR=1.6; CI: 0.3 to 8.3) were more prevalent among patients with keratoconus but did not reach statistical significance.

Cornea 2010;29:1261-4

Nemet AY, Vinker S, Bahar I, Kaiserman I.

Adding Latanoprost to Timolol Increases IOP Reduction Efficacy

Concomitant use of latanoprost and timolol leads to additional intraocular pressure reduction compared to the fixed combination of the drugs, say researchers at the Maastricht University Hospital in the Netherlands. To evaluate the IOP-lowering efficacy of prostaglandin analogs when added to topical beta-blockers, the group conducted a 19-year systematic review and meta-analysis of randomized clinical trials, studying 29 articles reporting on 33 study arms and three control arms. The pooled IOP-lowering effects at the one- to three-month follow-ups were calculated by performing random-effects meta-analyses. Outcomes were measured by the absolute and relative change in IOP for mean diurnal curve and highest and lowest IOP decrease on the diurnal IOP curve.

Adding 0.005% latanoprost in the evening to 0.5% timolol twice daily resulted in a pooled change of -6.3 mmHg (-7.1 to -5.5 mmHg, mean IOP curve); switching to the fixed combination of 0.5% timolol and 0.005% latanoprost in the morning resulted in a pooled change of -2.8 mmHg (-3.3 to -2.3 mmHg, mean IOP curve). Starting with any fixed combination of 0.5% timolol and a PGA in the morning resulted in a pooled change of -8.4 mmHg (-9.1 to -7.6 mmHg, mean IOP curve) and varied between -9.1 mmHg (-9.9 to -8.2 mmHg, highest) and -7.9 mmHg (-8.5 to -7.2 mmHg, lowest); starting with any fixed combination of 0.5% timolol and a PGA in the evening resulted in a pooled change of -8.6 (-9.2 to -8.0 mmHg, mean IOP curve) and varied between -10.1 mmHg (-11.0 to -9.2 mmHg, highest) and -7.3 mmHg (-8.1 to -6.4 mmHg, lowest).

Ophthalmology 2010;117:2067-74

Webers CA, Beckers HJ, Zeegers MP, et al.