The dome lens/hemisphere dome we manufactured be used to protect the lens of underwater camera,which could resist the pressure of water,and give a best view field to catch picture.
Specification of hemisphere dome we could supplied as follow:
Materials:BK7 glass,UV fused silica etc., various types of  optical glass.   
Diameter: from 10 to 250 mm.
Diameter Tolerance: 0.1 mm, standard; 0.01 mm - attainable.
Surface Quality: 60/40 Scratch/Dig ,standard;20/10 Scratch/Dig, attainable depending on material type and combination of other parameters.
Power/Irregularity: 5/1 (interference fringes),standard; 0.5/0.1 (interference fringes), attainable depending on material type and combination of other parameters. Aperture 60 deg.
Decentration: 0.05mm,standard; 0.01 ,attainable.