Risk Factors of Graft Failure in Post-Keratoplasty Ocular Hypertension

PURPOSE: To assess the risk factors proceeding to graft failure in post-keratoplasty ocular hypertension patients. METHODS: In 35 eyes diagnosed with post-keratoplasty ocular hypertension (graft failure: 13 eyes; graft survival: 22 eyes), relationships between graft status at the observation time and pre-keratoplasty diagnosis, lens status, history of graft failure, donor size, difference between donor and recipient graft size, donor corneal endothelial cell count, post-keratoplasty intraocular pressure (after 1 week and maintenance intraocular pressure after surgery), and number of antiglaucomatic agents were investigated. The relative risks of each factor to induce graft failure were also evaluated. RESULTS: Previous graft failure history, pre-existing pseudophakic bullous keratopathy and aphakia/pseudophakia showed statistically significant high probabilities of proceeding to graft failure (p < 0.05). In particular, the intraocular pressure 1 week after the graft was statistically higher (p < 0.05) in the graft failure group (24.31 +/- 8.82 mm Hg) than in the graft survival group (16.81 +/- 6.69 mm Hg). CONCLUSIONS: Strict management of intraocular pressure in the early phase of penetrating keratoplasty could contribute to reducing graft failure in post-keratoplasty ocular hypertension patients.

Transscleral Fixation of Intraocular Lens Using the Triple Cow-Hitch Method

PURPOSE: To report the results of scleral suture fixation using a hydrophilic acrylic intraocular lens (IOL) with 3 hollow haptics through a small corneal incision, the Triple Cow-Hitch Method. CASE SUMMARY: Three-point suture fixation of a XL Stabi ZO IOL was performed in 5 eyes of 5 patients with aphakia after penetrating keratoplasty (PKP), vitrectomy and subluxated lens extraction. Postoperatively, the corrected distance visual acuity and spherical equivalent improved in all measured eyes. There were no cases of pigment dispersion or cystoid macular edema (CME). CONCLUSIONS: In this preliminary study, the triple cow-hitch method of suturing a hydrophilic acrylic IOL is an alternative to the conventional 2-point scleral fixation of sutured IOLs.

Accuracy of Intraocular Lens Power Calculation Formulas in Primary Angle Closure Glaucoma

PURPOSE: To compare the accuracy of intraocular lens (IOL) power calculation formulas in eyes with primary angle closure glaucoma (ACG). METHODS: This retrospective study compared the refractive outcomes of 63 eyes with primary ACG with the results of 93 eyes with normal open angles undergoing uneventful cataract surgery. Anterior segment biometry including anterior chamber depth, axial length, and anterior chamber depth to axial length ratio were compared by the IOL Master. Third generation formulas (Hoffer Q and SRK/T) and a fourth generation formula (Haigis) were used to predict IOL powers in both groups. The predictive accuracy of the formulas was analyzed by comparison of the mean error and the mean absolute error (MAE). RESULTS: In ACG patients, anterior chamber depth and the anterior chamber depth to axial length ratio were smaller than normal controls (all p < 0.05). The MAEs from the ACG group were larger than that from the control group in the Haigis formula. The mean absolute error from the Haigis formula was the largest and the mean absolute error from the Hoffer Q formula was the smallest. CONCLUSIONS: IOL power prediction may be inaccurate in ACG patients. The Haigis formula produced more inaccurate results in ACG patients, and it is more appropriate to use the Hoffer Q formula to predict IOL powers in eyes with primary ACG.