ABSTRACT
PURPOSE: To evaluate the accuracy of intraocular lens (IOL) power calculation after an intrastromal femtosecond laser procedure to treat presbyopia using a theoretic approach. SETTING: International Vision Correction Research Centre, Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. DESIGN: Nonrandomized clinical trial. METHODS: Preoperatively and 12 months after intrastromal femtosecond laser treatment (IntraCor) of presbyopia, biometry was performed by partial coherence interferometry (PCI) (IOLMaster). The postoperative keratometry (K) values and IOL power calculation formulas (Holladay I, Haigis, SRK/T, Hoffer Q) were compared with results derived from the clinical history method, taking the manifest refraction change into account. RESULTS: The study enrolled 25 patients (median age 54 years). Three eyes were excluded for age-related lens changes. The median spherical equivalent change in the other 22 eyes was -0.38 diopter (D). The median difference in K values between the clinical history method and PCI was -0.21 D, resulting in a median IOL power difference between -0.23 D (SRK/T) and -0.29 D (Haigis) (range -1.58 to +1.00 D). The IOL power was underestimated in 59.1% of cases with the Hoffer Q and 63.6% of cases with the Holladay I, Haigis, and SRK/T. There was a difference of ±0.75 D in 72.7% of eyes using the Holladay I, Haigis, and Hoffer Q and in 86.4% of eyes using the SRK/T. Neither K values nor IOL power differences were statistically significant (P > .17). CONCLUSION: Intraocular lens power calculation using modern standard formulas incorporated in a PCI biometry device after intrastromal femtosecond presbyopia treatment was reliable, with minimum underestimation on average.
Subject(s)
Corneal Stroma/surgery , Laser Therapy/methods , Lasers, Excimer/therapeutic use , Lenses, Intraocular , Optics and Photonics , Presbyopia/surgery , Aged , Biometry , Humans , Interferometry , Middle Aged , Models, Theoretical , Refraction, Ocular/physiology , Reproducibility of Results , Visual Acuity/physiologyABSTRACT
PURPOSE: To investigate early functional outcomes of the INTRACOR femtosecond laser-based intrastromal procedure to treat presbyopia. METHODS: Twenty-five eyes of 25 presbyopic patients were enrolled in this prospective, ethics committee-approved study. Following detailed preoperative examination, the INTRACOR procedure was performed using the TECHNOLAS femtosecond laser (Technolas Perfect Vision GmbH) in the non-dominant eye. Postoperatively, follow-up examinations were performed at 1 day, 1 week, and 1 and 3 months, including near and distance visual acuity, slit-lamp microscopy, and corneal topography. RESULTS: All 25 surgeries were uneventful. The mean postoperative uncorrected near visual acuity increased from 0.7+/-0.16 logMAR to 0.26+/-0.21 logMAR and the mean uncorrected distance visual acuity changed slightly from 0.11+/-0.11 logMAR to 0.05+/-0.1 logMAR at 3 months postoperative. Regarding best distance correction, mean sphere changed from +0.75+/-0.23 diopters (D) preoperatively to +0.15+/-0.31 D postoperatively and mean cylinder from -0.33+/-0.17 D to -0.42+/-0.23 D. Postoperative healing was uneventful, and in all eyes, the cornea was clear within a few hours after surgery without any remaining cavitation gas bubbles. CONCLUSIONS: The INTRACOR procedure for presbyopia showed good visual acuity outcomes in the early postoperative period. The short treatment time in combination with maintained corneal integrity suggests this new technique has good potential for the treatment of presbyopia.
Subject(s)
Corneal Stroma/surgery , Keratomileusis, Laser In Situ/methods , Lasers, Solid-State/therapeutic use , Presbyopia/surgery , Aged , Biomechanical Phenomena , Contrast Sensitivity/physiology , Corneal Topography , Follow-Up Studies , Humans , Middle Aged , Presbyopia/physiopathology , Prospective Studies , Treatment Outcome , Visual Acuity/physiology , Wound Healing/physiologyABSTRACT
We describe the analysis of accommodation using wavefront measurements in phakic and pseudophakic eyes. Accommodation measurements were performed in phakic and pseudophakic eyes using a dynamic stimulation aberrometry (DSA) device (Optana) as an attachment to the WASCA aberrometer (Carl Zeiss Meditec AG). Aberrations were measured for distance fixation (3.0 m) and near fixation (0.3 to 0.11 m) presenting different accommodative stimuli (3.0 to 9.0 diopters). The device was able to detect changes in aberrations using near and distance stimulation. Eyes with phakic iris-fixated intraocular lenses (IOLs) showed normal age-correlated accommodation. In pseudophakic eyes, accommodation varied depending on the IOL. With monofocal IOLs (eg, MA60AC, Alcon), there was no accommodation; with an accommodating IOL (eg, Synchrony, Visiogen), there was a low level of accommodation. The DSA device is capable of measuring accommodation using wavefront data. It will help to further analyze changes in accommodation-related wavefront aberrations.
