Kyu Yeon Hwang

Pupil-size alterations induced by photodisruption during femtosecond laser-assisted cataract surgery

Purpose To measure miosis after femtosecond laser pretreatment of cataract surgery and determine correlative factors. Setting Department of Ophthalmology and Visual Science, Seoul St. Mary’s Hospital, College of Medicine, and Catholic University of Korea, Seoul, South Korea. Design Cross‐sectional study. Methods Images extracted from surgical videos of femtosecond laser pretreatment and phacoemulsification were used to measure the pupil area. Quantitative analysis of pupil constriction was performed by comparing consecutive images obtained at the initiation of each procedure. Potential factors related to pupil constriction were examined, including laser parameters and anatomic measurements. Results The study enrolled 56 eyes. The mean pupil area decreased by 29.7% during the time it took to shift between procedures (shifting time). The total laser treatment duration was highly correlated with the reduction in the pupil area (r = −0.433, P = .001). The amount of intraoperative miosis was significantly correlated with the duration of lens fragmentation by the femtosecond laser (r = −0.416, P = .001) and of primary incision creation (r = −0.289, P = .031). Pupil constriction was correlated with patient age (r = −0.398, P = .002) and the laser capsulotomy–pupil margin distance (r = 0.395, P = .003), but not with suction‐on time (r = −0.012, P = .930) or shifting time (r = −0.091, P = .506). Conclusions The pupil area decreased significantly after femtosecond laser pretreatment of cataract surgery. Intraoperative miosis was most significantly correlated with laser pretreatment duration and patient age. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Intraocular lens prediction accuracy after corneal refractive surgery using K values from 3 devices

Purpose To compare results of intraocular lens (IOL) power calculation methods using different keratometry (K) values after myopic refractive surgery. Setting Seoul St. Mary’s Hospital, Seoul, South Korea. Design Evaluation of diagnostic test or technology. Methods The IOL power of patients who had cataract surgery after refractive surgery was calculated using the SRK/T formula with true net power (TNP) and the equivalent K using the Pentacam Scheimpflug system. The simulated K, 2.0 mm zone of total mean power (TMP 2.0 mm) maps, and 4.0 mm zone of total optical power (TOP 4.0 mm) maps were calculated using the Orbscan II scanning‐slit topographer and keratometer of the IOLMaster partial coherence interferometer (PCI). The IOL power was also calculated with the Haigis‐L method with the corneal radius using the PCI system. The PCI axial length was used with all methods. Results The prediction error and absolute prediction error measured with the Haigis‐L, TNP, TMP 2.0 mm, and TOP 4.0 mm were significantly lower than the equivalent K, simulated K, and PCI K (P<.05). The percentages of correct refraction predictions within ±0.50 diopter (D), ±1.00 D, and ±2.00 D in the Haigis‐L method were the highest (64.5%, 80.6%, and 100%, respectively) of all methods. Conclusions The Haigis‐L using corneal radius with the PCI measurement was the most predictable method for IOL calculation after corneal refractive laser surgery in patients without a clinical history. The TMP 2.0 mm in the scanning‐slit topographer and the TNP in the Scheimpflug system may also be relatively predictable keratometric values for IOL calculation. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.