Optical biometry before and after surgical treatment of vitreoretinal pathology

Purpose. To compare the results of optical biometry provided by «IOLMaster 500», «IOLMaster 700», «Lenstar LS 900» and «Revo Soct Copernicus» in eyes with silicone oil tamponade after vitreoretinal surgery and after its removal. Material and methods. 56 silicone filled eyes (56 patients) after macular hole surgery, epiretinal fibrosis, retinal detachment with PVR stage C and endophthalmitis treatment measurements were made with «IOLMaster 500», «IOLMaster 700», «Lenstar LS 900» and «Revo Soct Copernicus» biometers in special mode foe silicone oil filled eye. For all eyes axial length (AL) without silicone oil was also determined. Cases with sclera buckling between evaluations were excluded. AL of eyes without silicone oil varied from 21.99 mm to 29.38 mm (24.36±1.74 mm) according to «IOLMaster 500» data. The average age of patients was 65.69±13.74 years (from 25 to 86 years). Results. For all patients difference of axial length in silicone filled eye and eye without silicone oil was evaluated. All patients were divided into 2 groups: I group - eyes with AL less than 23.625 mm and II group - AL more than 23.625 mm. According to «IOLMaster 700» and «Lenstar LS 900» difference between measurements was significant and amounted -0.11±0.05 mm (p = 0.043) and -0.09±0.18 mm (p = 0.018) respectively. In the II group disparity was also valid: 0.19±0.41 mm (p = 0.002) for «IOLMaster 500» data, 0.16±0.41 mm (p = 0.010) for «Lenstar LS 900» and 0.12±0.06 mm (p = 0.027) for «Revo Soct Copernicus» measurements. Conclusions. Despite of special biometric modes usage in AL measurement in the silicone oil filled eyes if it less than 23.625 mm axial length values significantly underestimated according to «IOLMaster 700» and «Lenstar LS 900» data. That could give an IOL calculation error about 0.3 diopters. In the same way AL in the silicone oil filled eyes if it exceeds 23.625 mm is reliably overstated according to «IOLMaster 500», «Lenstar LS 900» and «Revo Soct Copernicus» measurement. This leads to IOL calculation error about 0.6 diopters.