NBEO 2 - OPTICS EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026

NBEO 2 - OPTICS EXAM QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026 What limits visual acuity with pinhole - Answers diffraction what is involved in visual motor integration - Answers visual input, central processing, motor output The reversal of letters is a normal part of visual and motor development until what age - Answers 7 conversions between M notation, snellen, and MAR - Answers 20/20 = 1M @ 1meter = 1 MAR how much prism is needed for high add powers - Answers 2 + sphere power, over both eyes M unit definition - Answers size of a symbol that subtends 5 arc minutes at 1 meter and equivalent to snellen 20/20. 1.45 mm in height Preferred retinal locus - Answers desired point for viewing in eccentric fixation how do you determine amount of mag needed at near given near BCVA - Answers current BCVA/goal BCVA * wd formula for RDM - Answers original/near (DON) formula for RSM - Answers new/original (SNO) formula for angula mag - Answers new/origianl image size lateral mag formula - Answers m = L/L', Hi/Ho, (ratio of object size and image size) formula for stand magnifiers - Answers M = F/4 +1 formula for linear field of view - Answers w = d/Fe*l (lens diameter/equivalent power*distance between magnifier and spec plane) Formula for stand magnifier used with an add - Answers Fe/1 max possible add for a stand magnifier - Answers F/4 +1 Formula for mag of a telescope - Answers DENT/DEX, -Foc/Fobj telescope labeling - Answers magnification X obj lens diameter/entrance pupil diameter in mm what (-) lenses are commonly used for reverse telescopes - Answers -5.00 to -10.00 at arms length for spotting what mirror in gonio can be used to view the post pole - Answers central/hubry what mirror in gonio can view the angle and ora serrata - Answers smallest/bullet/thumbnail what mirror in gonio can be used to view ant equator and perip retina - Answers middle/square properties of a lensometer - Answers clear image leaves when parallel light leaves the standard lens at the primary focal point of the test lens lensometer fomula - Answers f2Fv where are the two images clear in a radioscope - Answers surface of lens, center of curvature of CL why do higher power lenses cause less mag in the slit lamp - Answers creation of a reverse telescope system general sphere trends for ANSI stanard - Answers more strict for low powers general ANSI standard for PALs - Answers allow more room for error general ANSI standard for cyl - Answers more strict for low powers general ANSI standard for axis - Answers more strict for high powers how do you make frame adjustments for A size - Answers height of segment is corrected by 1/2 difference between sample size and desired size how do you correct for groove depth in a frame - Answers add 0.50 mm if metal, add 1.0 mm in plastic how do you measure bifocal height - Answers lower eyelid/limbus to bottom of lens where do you put the seg for a double d seg - Answers automatically placed at 13-14 mm bove lower seg how do you measure fitting height for a trifocal - Answers align the lwoer pupil margin with 0 then measure down to eyewire intersection and subtract 1 to compensate for distance viewing (example 18 becomes 17) where do yuou measure distance power in a PAL - Answers top semi circle where do you measure fitting height in a PAL - Answers cross in the top semi circle where do you measure prism in a PAL - Answers dot under the fitting cross in the top semi circle how do you fit a PAL in a child - Answers fit 4 mm higher than adults to guarantee use how do you measure add power in a lensometer - Answers turn glasses around and remeasure distance above the OC then measure the near index/abbe of poly - Answers 1.586, 30 index/abbe for crown glass - Answers 1.523, 58.9 index/abbe for trivex - Answers 1.53, 43-45 index/abbe for CR 39 (plastic) - Answers 1.498, 58 upper and lower limit of tscherning ellipse - Answers +7.50, -22.50 power error/curvature of field - Answers difference in effective power in the center of the lens compared to lens edge, curved image on a plane object corrected curve lenses - Answers lenses that havecorrected RA COF or both distortions in (-) lenses - Answers barrel distortions in (+) lenses - Answers pincushion relationship between chromatic aberration and abbe value - Answers increased abbe = decreased CA, inversely related how can you quickly correct for chromatic aberration - Answers decrease vertex dist and use sufficient panto tilt how can you quickly correct for curvature of field - Answers minimize with use of manufacturers recommendation how can you quickly correct for radial astigmatism - Answers tscherning ellipse how can you quickly correct for spherical/coma aberration - Answers aspheric lenses if 7.00 prism in aspheric lenses - Answers must be ground in slab off - Answers lower half has more minus, base up (BUMM) reverse slab off - Answers lower has BD, base down most plus when are patients likely to complain about vertical imbalance problems - Answers if lens power in vertical meridian differs by 1.50 D and the pt is wearing a BF when will aniseikonia prevent fusion - Answers if difference is .10% how can you relieve aniseikonia - Answers decrease difference between SM of the two lenses accommodation trends in ametropes - Answers hyperopes converge more in specs than CL, myopes converge more in CL than specs