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Published on: May 25, 2020
Rarebit perimetry and fovea test before and after cataract surgery
Maria Nilsson1, Oran Abdiu, Carl-Gustaf Laurell
1Unit of Optometry, Department of Clinical Neuroscience, Karolinska Institut, Stockholm, Sweden. maria.nilsson@ste.ki.se
Purpose:
To evaluate the effect of cataract on rarebit perimetry and the fovea test.
Methods:
Twenty-five consecutive patients scheduled for cataract surgery (mean age 63.0 +/- 7.9 years) were examined prior to and after cataract surgery with a complete ophthalmological examination. In addition, the rarebit perimetry (RBP) and the rarebit fovea test (RFT) were performed.
Results:
Best-corrected visual acuity [BCVA, expressed in minimum angle of resolution (MAR)], RBP and RFT mean hit rate (MHR) improved significantly after cataract surgery. The relative pre-postsurgery difference was larger in the RFT [2.1 standard deviations (SDs)] compared to in BCVA (0.78 SDs). Seven patients had good BCVA (< or = 1.25) and RBP (83-99%) but low RFT (0-66%) before surgery. One patient with low preoperative BCVA (2.5) had a normal RFT (94%).
Conclusion:
Cataract influenced both the RFT and RBP test, albeit the former more than the latter. The influence of cataract on RFT results, even when visual acuity is decreased only moderately, has to be taken into account when evaluating foveal function in patients with cataract. The larger relative change in RFT compared to BCVA values is thought to indicate that RFT is more sensitive for the effect of cataract. Therefore, RFT appears to be a sensitive test for visual disturbance and can presumably provide additional information at the preoperative evaluation of the patient.
