Huanyu Digital Pupilometer Optical PD Meter Pupil Distance Meter Measuring Tool Pupilary Distance Meter CE Approved (LY-9C)

Product works great for the cost. Can you offer any additional information regarding specs, or the item being calibrated.

This gave wrong PD measurements which resulted in having to have my lenses made over again. It was not an operator error but the device giving wrong measurements as verified by my optometrist. I was skeptical about others making this comment and thought they must be using it wrong etc. It seems the devices are not calibrated and have no way of calibrating them. Gave a reading of 28.5 and 32.5 but my actual PD is 30.0 and 30.5

innacurate. poorly calibrated.

I like this device and it does work well. you must have good overhead lighting to get good results. I don't see anything in the manual about the metal bar. It has to be pushed up (and it can because it's spring loaded) to get your nose to rest on the nose part of the device. The manual does not mention anything about this metal bar. Is it supposed to be kept in position for distance away from forehead? will this affect measurement? You can't properly position nose without pushing it up out of the way, so are you supposed to ignore nose gap on device? I do see where you have to keep it level, and it sees your pupils better with good overhead lighting. It does state to use the infinity setting for accurate measurement, so why is this setting even allowed to be changed? Manual is very lacking in proper instructions for this device. Slides for alignment seem to have enough resistance (stiffness to hold their place) to keep them in place once proper distance is achieved but I do wonder if they will get loose over time. Digital readout is extremely nice and auto on/off works fine, but kinda touchy to turn on if you move it around much. I would prefer an on/off switch instead. Battery area is not of the best design, not well protected, broadly open to circuit board. Access to batteries is good. Personally I would prefer some rubber material on sides and just a little ways in on top and bottom for more comfortable grip when measuring someones pupils. It isn't a major factor, but for it's price I would expect it. If your supposed to keep the metal bar against forehead, it should be flat with rubber grip on the part that does go against your head to get a more secure and comfortable position to read. The skinny round metal poking you in the forehead isn't the best nor comfortable design. Accuracy and ease of use both get a star loss because of these issues. Value for the money is what it is. To pay well over 100.00 for no more than it does is very steep in my opinion. I do not feel it costs no way near that much to make with what is there. From what research I done on Amazon before my purchase I do feel this is the best made device available.

Measurements are off in one eye. This is even after 2 exchanges. NOT accurate at all!