A study observing incidence, course and common factors in patients afflicted with negative dysphotopsia has led to the hypothesis that the corneal edema associated with a beveled temporal incision made during cataract surgery contributes to transient negative dysphotopsia.
A private practice worked in conjunction with the University of Cincinnati College of Medicine on the study, which implanted an IOL during phacoemulsification. The study was performed in 250 consecutive routine cataract procedures. On the first postoperative day, patients were asked if they noticed a temporal shadow and were then the subject of serial evaluations (via subjective questionnaires and objective testing) for three years.
Results of the evaluations showed an incidence of negative dysphotopsia in 15.2 percent of the observed patients on the first postoperative day, decreasing to 3.2 percent after one year, then 2.4 percent after two and three years. Common findings included a shallow orbit, prominent globe, space 0.45 mm between the iris and IOL by ultrasound biomicroscopy, and perimetric comet-shaped light in the area corresponding to the shadow. Slit lamp revealed a transparent peripheral capsule and a shadow sign in which a linear shadow on the iris became curvilinear as the light from the slit beam was projected through the incision toward the pupil.
By the close of the study, two groups of patients experienced negative dysphotopsia that rapidly resolved or remained unchanged from the first postoperative day.
(J Cataract Refract Surg 2008;34:1699-1707)
Perioperative Ketorolac Reduces CME
A study suggests that adding perioperative ketorolac to postoperative prednisolone significantly reduces the incidence of CME and macular thickening in cataract surgery patients who are at low risk for the condition.
The prospective, randomized, investigator-masked multicenter clinical evaluation was performed on behalf of the Acular LS for Cystoid Macular Edema (ACME) study group and was performed on patients with 20/20 BCVA potential without any evidence of macular abnormality. Patients were randomized to receive prednisolone acetate 1% q.i.d. alone (steroid group; n=278) or prednisolone 1% q.i.d. plus ketorolac 0.4% q.i.d. (ketorolac/steroid group; n=268) for approximately four weeks postoperatively. Patients in both groups received four doses of ketorolac 0.4% one hour before surgery; however, the ketorolac/steroid group also received topical ketorolac 0.4% q.i.d. for three days preoperatively.
Results showed that none of the patients in the ketorolac/steroid group and only five patients in the steroid group had clinically apparent CME (p=0.032). An OCT showed that none of the ketorolac/steroid patients had definite or probable CME, compared with
six steroid patients (2.4 percent; p=0.018). In the ketorolac/steroid group, mean retinal thickening was less (3.9 µm vs. 9.6 µm; p=0.003), and fewer patients had retinal thickening of more than 10 µm as compared with the steroid group (26 percent vs. 51 percent; p<0.001).
(AM J Opthalmol 2008;146:554-560.)
Wittpenn JR, Silverstein S, Heier J, Kenyon KR, et al.