Corneal biomechanical properties after laser-assisted in situ keratomileusis and photorefractive keratectomy.

BACKGROUND: The purpose of this study was to evaluate the effects of laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) on corneal biomechanical properties. METHODS: We used the ocular response analyzer to measure corneal hysteresis (CH) and corneal resistance factor (CRF) before and after refractive surgery. RESULTS: In all, 230 eyes underwent LASIK and 115 eyes underwent PRK without mitomycin C (MMC). Both procedures decreased CH and CRF from baseline. When MMC was used after PRK in 20 eyes, it resulted in lower corneal biomechanical properties at 3 months when compared to the other procedures, but all three procedures had similar values at 12 months. CONCLUSION: Significant but similar decreases in corneal biomechanical properties after LASIK, PRK without MMC, and PRK with MMC were noted.

LASIK Enhancement: Clinical and Surgical Management.

PURPOSE: To review refractive regression and current therapeutic options for patients who have residual refractive error after LASIK. METHODS: An extensive literature search using PubMed was performed for terms such as "LASIK," "PRK," "enhancement," "overcorrection," "undercorrection," "re-lift," "mini-flap," and related terms. RESULTS: The presence of residual refractive error following LASIK is a challenging situation. After excluding anatomical causes (eg, ocular surface disease, cataract, and macular pathology) and intraoperative flap complications, evaluation of the residual stromal bed must be performed. Depending on the length of time since primary LASIK, procedures such as flap re-lift, flap re-cut, and surface ablation may be performed. CONCLUSIONS: Residual refractive errors can be seen after LASIK surgery and may benefit from an enhancement procedure. Different options are available for enhancement, each requiring proper evaluation and an analytical approach to make the procedure safe and effective. [J Refract Surg. 2017;33(2):116-127.].

Ocular manifestations and management recommendations of lysosomal storage disorders I: mucopolysaccharidoses.

The mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders caused by inborn errors of glycosaminoglycan (GAG) metabolism. These diseases are classified by enzyme deficiency into seven groups: type I, II, III, IV, VI, VII, and IX. GAG accumulation leads to characteristic clinical features. Some ophthalmic findings that are characteristic of MPS diseases include corneal clouding, retinal degeneration, decreased electroretinogram wave amplitude, optic atrophy, papilledema, and glaucoma. Current treatments such as hematopoietic stem cell transplantation and enzyme replacement therapy have increased the life span of many MPS patients and created the need to improve management of ocular symptoms. This article aims to provide a comprehensive review of ocular manifestations and treatment options for the various types of MPS.

Small-incision lenticule extraction.

UNLABELLED: This review looks at the benefits, limitations, complications, and future applications of the small-incision lenticule extraction procedure. Using the search terms small incision lenticule extraction and femtosecond lenticule extraction, we obtained data from 56 articles (omitting German and Chinese articles) from the PubMed database. Small-incision lenticule extraction has shown efficacy, predictability, and safety that are proportionate to those of laser in situ keratomileusis (LASIK), with the additional benefit that it eliminates flap creation and the attendant risks. The potential advantages of the procedure related to improved biomechanical stability, postoperative inflammation, and dry-eye symptoms have not been fully established. Small-incision lenticule extraction-treated eyes have shown a reduced degree of postoperative corneal denervation and higher-order aberrations and an accelerated rate of corneal nerve convalescence relative to LASIK. Future possibilities related to long-term cryogenic storage of extracted lenticules with eventual reimplantation or donation have been investigated with encouraging preliminary results. FINANCIAL DISCLOSURE: Drs. Reinstein and Shah are consultants to Carl Zeiss Meditec AG. No author has a financial or proprietary interest in any material or method mentioned.

The impact of suction drainage on orbital compartment syndrome after craniofacial surgery.

PURPOSE: Postoperative orbital compartment syndrome is a potentially blinding complication of surgery in the orbital region. We describe the technique of orbital drain placement as a method of preventing vision loss resulting from orbital compartment syndrome. METHODS: We present a retrospective case series of 29 patients who underwent orbital fracture, facial fracture, and orbital implant removal from 7/4/2008 to 5/3/2013 by the same craniofacial surgeon. An orbital drain was placed in each patient. The drainage was recorded daily until drain removal. Criteria for removal included less than or equal to 5 mL of drainage in 24 hours. RESULTS: Of the 29 patients included in this study, 21 were men and 8 were women. Ages ranged from 17 to 67 years. The postoperative drainage ranged from less than 1 mL to 71 mL of serosanguinous fluid. All drains were removed between the first and sixth postoperative days. No postoperative visual loss, infections, or additional antibiotics were recorded with follow-up reaching as far as 40 months. CONCLUSIONS: Postoperative orbital compartment syndrome is a dangerous complication of surgery in the orbital region. Its rapid onset necessitates immediate intervention to prevent permanent vision loss. Morphologic changes to the optic nerve as well as reductions in electroretinogram a- and b-wave amplitudes have been demonstrated with as little as 7 mL of fluid accumulation. Intraoperative orbital drain placement should be considered in all patients undergoing surgery in the orbital region as a preventative measure.

Descemet stripping automated endothelial keratoplasty using donor corneas with previous laser in situ keratomileusis or photorefractive keratectomy: a case series and donor cap histopathology.

PURPOSE: To report outcomes in Descemet stripping automated endothelial keratoplasty (DSAEK) using donor tissue from eyes that have had previous refractive surgery and to report histopathology of the donor free cap. METHODS: Retrospective case series. Preoperative and postoperative data were collected on each patient, and donor information was collected. Histopathologic evaluation was carried out on donor caps to determine the stability of the laser in situ keratomileusis (LASIK) flap and smoothness of the microkeratome cut during preparation of the donor. RESULTS: DSAEK was performed on 7 eyes using donors that had undergone photorefractive keratectomy (PRK) or LASIK. One patient received PRK donor tissue, had no interface haze, and had improvement in vision. All but one patient who received LASIK donor tissue had improvement in vision, and that patient had severe graft folds noted intraoperatively that persisted. Histopathologic examination of 3 donor caps showed mild to moderate dehiscence of the LASIK flap, but the cut interface was consistent with normal donor tissue preparation histopathology. CONCLUSIONS: We report the first case of DSAEK using PRK donor tissue, which was successful. Our experience with LASIK donor tissue was comparable to nonrefractive donor tissue with the exception of the persistent donor macrofolds in one patient.

Simultaneous and sequential implantation of intacs and verisyse phakic intraocular lens for refractive improvement in keratectasia.

PURPOSE: To evaluate the safety, efficacy, and visual outcomes of simultaneous and sequential implantation of Intacs (Addition Technology, Inc, Sunnyvale, CA) and Verisyse phakic intraocular lens (AMO, Santa Ana, CA) in selected cases of ectatic corneal disease. SETTING: John A. Moran Eye Center, University of Utah, UT. METHODS: Prospective data were collected from 19 eyes of 12 patients (5 eyes, post-laser in situ keratomileusis ectasia and 14 eyes, keratoconus). Intacs segments were implanted followed by insertion of a phakic Verisyse lens at the same session (12 eyes) in the simultaneous group or several months later (7 eyes) in the sequential group. The uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), and manifest refraction were recorded at each visit. RESULTS: No intraoperative or postoperative complications were observed. At the last follow-up (19 ± 6 months), in the simultaneous group, mean spherical error was -0.79 ± 1.0 diopter (D) (range, -2.0 to +1.50 D) and cylindrical error +2.06 ± 1.21 D (range, +0.5 to +3.75 D). In the sequential group, at the last follow-up, at 36 ± 21 months, the mean spherical error was -1.64 ± 1.31 D (range, -3.25 to +1.0 D) and cylindrical error +2.07 ± 1.03 D (range, +0.75 to +3.25 D). There were no significant differences in mean uncorrected visual acuity or BSCVA between the 2 groups preoperatively or postoperatively. No eye lost lines of preoperative BSCVA. CONCLUSIONS: Combined insertion of Intacs and Verisyse was safe and effective in all cases. The outcomes of the simultaneous implantation of the Intacs and Verisyse lens in 1 surgery were similar to the results achieved with sequential implantation using 2 surgeries.