Corneal biomechanics in age-related macular degeneration

Purpose To compare the corneal hysteresis (CH) and the corneal resistance was increase force (CRF) of patients with age-related macular degeneration (ARMD) and control subjects. Methods The CH and the CRF were compared among 20 patients with ARMD (ARMD group: 10 with neovascular and 10 with non-neovascular ARMD) aged from 54 yrs to 78 yrs (68.9±15.9 yrs) and 20 age-matched control patients (control group). In ARMD and control group the eye's axial length was: 23.14 ±0.95 mm vs. 23.04 ±1.16 mm (p<0.715) and the corneal thickness was: 555.1±3.08 vs. 558±4.14 µ (p<0.274). The CH and CRF values were achieved by ocular response analyzer (ORA). Results We found a statistical significant difference in the CRF between patients with ARMD and control subjects (ARMD group 11.13±1.30 vs. control group: 9.82±1.37; p<0.001) was found. A difference, but no stastical significant was found also for CH index between patients with AMD and control subjects (ARMD group: 10.15±1.25 vs. control group: 10.02±1.68 mm/hg; p<0.376). When we examined separately the two subgroups of patients with ARMD (neovascular and nonneovascular ARMD), the average CH were higher in patients with neovascular AMD compared with patients with non-neovascular ARMD (neovascular ARMD group: 10.77±1.00 vs. non-neovascular ARMD 10.17±1.08; p<0.074) and CRF was also increased in neovascular ARMD (neovascular ARMD group: 11.86±0.99 vs. non-neovascular ARMD 10.88±1.37; p<0.032). Conclusion Despite the limitations placed by the small sample of the examined cases, patients with ARMD had a statistical significant increase of CRF compared with healthy control group. Furthermore we found the same statistical significant increase of CRF in neovascular ARMD patients compared with non-neovascular ARMD