CPO CPO Clinical Principles and Procedures 3

Question 1

A patient with early-stage glaucoma has a reliable Humphrey Visual Field (HVF) 24-2 test that appears normal. However, the optometrist suspects central defects based on OCT findings. Which of the following ancillary tests would be most appropriate for the paraoptometric to perform to investigate this specific concern?

Accepted Answer

A 10-2 visual field test to get higher resolution of the central area.

Answer

While a 24-2 test is a standard for glaucoma, it can miss early paracentral defects near fixation. The 10-2 visual field test provides a higher resolution by testing more points (68) within the central 10 degrees, making it more sensitive for detecting subtle defects close to the center of vision that may be indicated by OCT scans but missed on the 24-2 protocol.

Question 2

A long-time progressive lens wearer complains of a persistent 'swimming' sensation and intermittent blur with their new glasses, despite the Rx and measurements being verified as correct. The frame has been adjusted for optimal pantoscopic tilt and face form. What is the most likely underlying cause for this non-adapt issue?

Accepted Answer

The progressive lens design is too 'hard' compared to their previous pair.

Answer

When standard fitting parameters are correct, persistent 'swim' and peripheral distortion in an experienced wearer often points to an issue with the lens design itself. A 'harder' progressive design has a wider distance and near zone but a more rapidly increasing power corridor, which creates more peripheral aberration. This can induce the swimming sensation for patients accustomed to a 'softer' design with smoother transitions.

Question 3

During a contact lens follow-up, a patient wearing monthly toric lenses complains of fluctuating vision, especially after blinking. Upon slit lamp examination, the paraoptometric notes the toric orientation marking is consistently rotated 15 degrees nasally in the right eye. The over-refraction is +0.25 -0.75 x 100. The current lens is 8.6 BC, 14.5 Diam, -2.00 -1.25 x 085. Applying the LARS rule, what new diagnostic lens axis should be ordered?

Accepted Answer

070 degrees

Answer

LARS stands for Left Add, Right Subtract. Since the lens is rotated to the paraoptometric's left (nasally in the right eye), you must ADD the 15 degrees of rotation to the original prescribed axis of 085. However, this common application of LARS is from the practitioner's view. A more precise way to think is if the lens rotates nasally (patient's left for the right eye), the correcting axis must be moved temporally. In this case, subtracting from the axis is required for nasal rotation. Thus, 85 degrees - 15 degrees = 70 degrees. This compensates for the consistent rotation to provide stable, clear vision.

Question 4

A 10-year-old is undergoing amblyopia therapy. The prescribed regimen is patching the dominant eye for two hours daily. The parents report inconsistent compliance and ask about alternatives. Which of the following is an equally effective, evidence-based alternative for treating moderate amblyopia in this age group?

Accepted Answer

Weekend-only atropine penalization of the dominant eye.

Answer

Large-scale clinical trials, such as those by the Pediatric Eye Disease Investigator Group (PEDIG), have shown that for moderate amblyopia (20/40 to 20/80), weekend atropine use is as effective as 2 hours of daily patching. Atropine drops blur the vision in the dominant eye, forcing the brain to use the amblyopic eye, which can be a more manageable option for families struggling with patch compliance.

Question 5

A paraoptometric is assisting with a low vision evaluation for a patient with advanced macular degeneration. The patient needs to read a newspaper. Which of the following devices would be most appropriate to try first, considering it allows for a wide field of view and keeps the hands free for holding the paper?

Accepted Answer

High-plus spectacle-mounted microscopes.

Answer

For a task like reading a newspaper, which requires a sustained near focus and benefits from having both hands available, high-plus spectacle-mounted microscopes are an excellent starting point. They provide a wide field of view compared to telescopes and free up the patient's hands, unlike hand-held magnifiers. While a CCTV is also hands-free and very powerful, it is less portable and a more complex electronic device to start with for this specific task.

(CPO) Certified Paraoptometric Practice Test

(CPO) Certified Paraoptometric Practice Test

CPO CPO Clinical Principles and Procedures 3