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While an increase in anterior chamber inflammation may be linked to corneal thickening early after cataract surgery, independent effects of prophylactic anti-inflammatory regimens may not be clinically relevant after accounting for the inflammation effects, according to authors of a study published in Clinical Ophthalmology.
A potential complication of cataract removal is corneal opacification, which is due to increased central corneal thickness (corneal edema). It typically resolves within days or weeks of surgery in most patients. However, some cases of increased corneal thickness are permanent, resulting in severe visual impairment. Anterior chamber inflammation (aqueous flare) and central corneal thickness increase postoperatively but their association is not often reported.
A team of investigators conducted a post-hoc analysis of a prospective randomized controlled trial (ClinicalTrials.gov Identifier: NCT03383328) to determine whether early postoperative anterior chamber inflammation is associated with central corneal thickness after cataract surgery. The researchers also aimed to evaluate the effect of anti-inflammatory prophylaxis on central corneal thickness.
A total of 456 patients who underwent cataract surgery at a single hospital in Copenhagen (mean age 72.7 years; 283 women) were randomly assigned to 1 of 5 intervention groups. Groups A and B consisted of patients who were treated with topical ketorolac (Acular 0.5%) and prednisolone (Pred Forte 1%, prednisolone acetate), groups C and D were treated with only topical ketorolac, and group E was treated with a subtenon depot of dexamethasone dihydrogen phosphate. Participants in groups A and C were administered eye drops 3 days before surgery and participants in groups B and D were administered eye drops postoperatively on the day of surgery. Members of groups A, B, C, and D were administered 3 drops daily for 3 weeks.
Aqueous flare was measured prior to surgery and 3 days after surgery, while central corneal thickness was measured before surgery, 3 days post surgery, 3 weeks post surgery, and 3 months post surgery.
Before surgery, the overall mean central corneal thickness was 549 µm; it increased to 594 µm 3 days after surgery but dropped to 562 µm 3 weeks after surgery and to 551 µm 3 months after surgery.
An increase in aqueous flare was linked to an increase in central corneal thickness 3 days after surgery. A twofold increase in aqueous flare was associated with an increase in central corneal thickness by 15.6 µm 3 days after surgery (P <.001); however, this effect was reduced to 2.8 µm 3 weeks after surgery and to 0.9 µm 3 months after surgery.
Compared with group A (control), patients in group C had a significantly thinner central corneal thickness 3 days after surgery (P =.03). No significant differences were noted among any other groups, and 20% of participants needed additional anti-inflammatory treatment.
A greater central corneal thickness before surgery was significantly associated with thicker central cornea 3 days after surgery (P <.001). Compared with group A, the mean anterior chamber cell count was significantly greater in group E 3 days after surgery (P =.004).
Corrected distance visual acuity was significantly likely to be reduced in patients with greater central corneal thickness 3 days after surgery (P <.001) but not 3 months after surgery (P =.81).
“A shallow anterior chamber depth was associated with corneal thickening after surgery,” according to investigators. “Corneal thickening is possibly mediated by underlying deterioration of the blood-aqueous barrier and corneal endothelium pump function caused by a postoperative inflammatory response.”
Reference
Hansen NC, Erichsen JH, Holm LM, Kessel L. Corneal thickness and anterior chamber flare after cataract surgery: a randomized controlled trial comparing five regimens for anti-inflammatory prophylaxis. Clin Ophthalmol. 2021;15:2835-2845. doi:10.2147/OPTH.S312350
