Peter T. Huang

Photorefractive keratectomy in children

Purpose: To evaluate photorefractive keratectomy (PRK) in pediatric patients who fail traditional methods of treatment for myopic anisometropic amblyopia and high myopia. Setting: Nonhospital surgical facility with follow‐up in a hospital clinic setting. Methods: Photorefractive keratectomy was performed in 40 eyes of 27 patients. The patients were divided into 4 groups based on the type of myopia: myopic anisometropic amblyopia (15 eyes/13 patients), bilateral high myopia (20 eyes/10 patients), high myopia post‐penetrating keratoplasty (3 eyes/2 patients), and combined corneal scarring and anisometropic amblyopia (2 eyes/2 patients). All procedures were performed under general anesthesia using the VISX 20/20 B laser and a multizone, multipass ablation technique. Appropriate corneal fixation was achieved with appropriate head positioning (turn and tilt) and an Arrowsmith fixation ring. Myopia was as high as −25.00 diopter (D) spherical equivalent (SE), but no treatment was for more than −17.50 D SE. Results: The mean SE decreased from −10.68 D to −1.37 D at 1 year, a mean change of −9.31 D. At 1 year, the mean best corrected visual acuity improved from 20/70 to 20/40 in the entire group. Forty percent of eyes were within ±1.0 D of the targeted refraction. There was no haze in 59.5% of eyes. Three eyes initially had 3+ haze; 1 improved to 2+ and 2 required repeat PRK with significant haze reduction. Five eyes (3 patients) with greater than −17.00 D SE myopia before PRK (range −17.50 to −25.00 D) had 3.42 D more effect than predicted (range 0.50 to 5.50 D). A functional vision survey demonstrated a positive effect on the childrens ability to function in their environments after the laser treatment. Conclusion: Photorefractive keratectomy in children represents another method of providing long‐term resolution of bilateral high myopia and myopic anisometropic amblyopia.

Laser-assisted subepithelial keratectomy for anisometropic amblyopia in children: outcomes at 1 year.

PURPOSE: To assess the refractive, visual acuity, and binocular results of laser‐assisted subepithelial keratectomy (LASEK) for anisomyopia, anisohyperopia, and anisoastigmatia in children with various levels of amblyopia secondary to the anisometropic causes. SETTING: Nonhospital surgical facility with follow‐up in a hospital clinic setting. METHODS: This retrospective review was of 53 children with anisometropia who had LASEK to correct the refractive difference between eyes. All LASEK procedures were performed using general anesthesia. Patients were divided into 3 groups according to their anisometropia as follows: myopic difference greater than 3.00 diopters (D), astigmatic difference greater than 1.50 D, and hyperopic difference greater than 3.50 D. The children were followed for at least 1 year, and their refractive status, visual acuity, and binocular vision were assessed and recorded at 2 and 6 months as well as 1 year. RESULTS: The mean age at treatment was 8.4 years (range 10 months to 16 years). The mean preoperative anisometropic difference was 6.98 D in the entire group, 9.48 D in the anisomyopic group, 3.13 D in the anisoastigmatic group, and 5.50 D in the anisohyperopic group. One year after LASEK, the mean anisometropic difference decreased to 1.81 D, 2.43 D, 0.74 D, and 2.33 D, respectively, and 54% of all eyes were within ±1.00 D of the fellow eye, 68% were within ±2.00 D, and 80% were within ±3.00 D. Preoperative visual acuity and binocular vision could be measured in 33 children. Postoperatively, 63.6% of children had an improvement in best corrected visual acuity (BCVA) and the remainder had no noted change. No patient had a reduction in BCVA or a loss in fusional ability after LASEK. Of the 33 children, 39.4% had positive stereopsis preoperatively and 87.9% had positive stereopsis 1 year after LASEK. CONCLUSION: Laser‐assisted subepithelial keratectomy is an effective surgical alternative to improve visual acuity in anisometropic children unable to tolerate conventional methods of treatment or in whom these methods fail.

Refractive laser surgery in children with coexisting medical and ocular pathology.

PURPOSE: To report the visual, refractive, and functional outcomes of photorefractive keratectomy (PRK) and of laser‐assisted subepithelial keratectomy in a group of children with significant refractive error and underlying medical conditions or ocular pathology who were noncompliant with traditional management. SETTING: Nonhospital surgical facility and a hospital clinic. METHODS: This case series comprised 5 individual cases of anisometropic amblyopia and/or high myopia. Underlying medical and ocular conditions were as follows: upper eyelid hemangioma with oblique myopic astigmatism, Pelizaeus‐Merzbacher leukodystrophy with nystagmus, Klippel‐Trenaunay‐Weber syndrome with glaucoma, incontinentia pigmenti with unilateral optic nerve atrophy, and Goldenhar syndrome with unilateral optic nerve hypoplasia. Photorefractive keratectomy or LASEK was performed in 6 eyes of 5 patients. Age range at the time of surgery was 1.0 to 7.0 years. All procedures were performed under general anesthesia. RESULTS: Best corrected visual acuity improved by 2 lines in 2 patients and 1 line in 2 patients by 6 months after surgery. Stereopsis and/or fusional status improved in 3 patients. Amblyopia treatment compliance improved in 1 patient. Alignment improved without strabismus surgery in 2 cases. A functional vision survey demonstrated a positive effect on the ability of all 5 children to function in their environment. CONCLUSION: During the period of visual cortical plasticity, refractive surgery, by eliminating the refractive component of amblyopia and by promoting fusional ability, provides considerable improvement in children, even those with underlying medical conditions associated with ocular pathology.

Laser-assisted subepithelial keratectomy and photorefractive keratectomy for post-penetrating keratoplasty myopia and astigmatism in adults

PURPOSE: To evaluate whether laser‐assisted subepithelial keratectomy (LASEK) and photorefractive keratectomy (PRK) achieve effective targeted correction and the extent of post‐treatment corneal haze after corneal transplantation. SETTING: Nonhospital surgical facility, Calgary, Alberta, Canada. DESIGN: Evidence‐based manuscript. METHODS: This study evaluated visual acuity, refractive error correction, and potential complications after LASEK or PRK to eliminate refractive error differences after penetrating keratoplasty in adults. A Nidek EC‐5000 or Technolas 217 excimer laser was used in all treatments. RESULTS: At last follow‐up (mean 20.50 months post laser), the mean spherical equivalent (SE) decreased from −2.71 diopters (D) ± 4.17 (SD) to −0.54 ± 3.28 D in the LASEK group and from −4.87 ± 3.90 D to −1.82 ± 3.34 D in the PRK group. The mean preoperative uncorrected distance visual acuity (UDVA) was 1.63 ± 0.53 and 1.45 ± 0.64, respectively, and the mean postoperative UDVA, 0.83 ± 0.54 and 0.90 ± 0.55, respectively. The improvement in SE and UDVA was statistically significant in both groups (P<.01). The mean haze (0 to 3 scale) at the last follow‐up was 0.46 ± 0.708 in the LASEK group and 0.58 ± 0.776 in the PRK group. CONCLUSIONS: The UDVA improved and refractive errors were effectively reduced after LASEK or PRK in eyes with previous PKP. There was no significant difference in the change in SE, UDVA, or corrected distance visual acuity between LASEK and PRK. Some patients had evidence of corneal haze, although the difference between the groups was not significant. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Laser-assisted subepithelial keratectomy for bilateral hyperopia and hyperopic anisometropic amblyopia in children: one-year outcomes.

PURPOSE: To assess the refractive, visual acuity, and binocular results of laser‐assisted subepithelial keratectomy (LASEK) in children with bilateral hyperopia or hyperopic anisometropic amblyopia. SETTING: Nonhospital surgical facility and hospital clinic, Calgary, Alberta, Canada. METHODS: This retrospective review comprised children with bilateral hyperopia or hyperopic anisometropic amblyopia who had LASEK. Refractive status, visual acuity, and binocular vision were assessed and recorded 2 months and 1 year postoperatively. RESULTS: The mean spherical equivalent (SE) in all 72 hyperopic eyes (47 patients) was +3.42 diopters (D) (range 0.00 to +12.50 D) preoperatively and +0.59 D (range −1.25 to +2.00 D) 1 year postoperatively. After LASIK, 41.7% of eyes had improved corrected distance visual acuity (CDVA). No patient had reduced CDVA or loss of fusional ability; there was a 25.0% improvement in stereopsis at 1 year. The mean anisometropic difference in the hyperopic anisometropic amblyopia subgroup (18 eyes, 10 patients) was 4.39 D (range +1.75 to +7.75 D) preoperatively and +0.51 D (range 0 to +0.875 D) at 1 year. One year postoperatively, 83% of anisometropic eyes were within ±1.00 D of the fellow eye and 94.0% were within ±3.00 D. Postoperatively, 64.7% of eyes had improved CDVA with no reduced CDVA or loss of fusional ability; there was a 22% improvement in stereopsis at 1 year. CONCLUSION: Laser‐assisted subepithelial keratectomy improved visual acuity in pediatric hyperopia with or without associated hyperopic anisometropic amblyopia. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

ArticleLaser-assisted subepithelial keratectomy for bilateral hyperopia and hyperopic anisometropic amblyopia in children: One-year outcomes

PURPOSE: To assess the refractive, visual acuity, and binocular results of laser‐assisted subepithelial keratectomy (LASEK) in children with bilateral hyperopia or hyperopic anisometropic amblyopia. SETTING: Nonhospital surgical facility and hospital clinic, Calgary, Alberta, Canada. METHODS: This retrospective review comprised children with bilateral hyperopia or hyperopic anisometropic amblyopia who had LASEK. Refractive status, visual acuity, and binocular vision were assessed and recorded 2 months and 1 year postoperatively. RESULTS: The mean spherical equivalent (SE) in all 72 hyperopic eyes (47 patients) was +3.42 diopters (D) (range 0.00 to +12.50 D) preoperatively and +0.59 D (range −1.25 to +2.00 D) 1 year postoperatively. After LASIK, 41.7% of eyes had improved corrected distance visual acuity (CDVA). No patient had reduced CDVA or loss of fusional ability; there was a 25.0% improvement in stereopsis at 1 year. The mean anisometropic difference in the hyperopic anisometropic amblyopia subgroup (18 eyes, 10 patients) was 4.39 D (range +1.75 to +7.75 D) preoperatively and +0.51 D (range 0 to +0.875 D) at 1 year. One year postoperatively, 83% of anisometropic eyes were within ±1.00 D of the fellow eye and 94.0% were within ±3.00 D. Postoperatively, 64.7% of eyes had improved CDVA with no reduced CDVA or loss of fusional ability; there was a 22% improvement in stereopsis at 1 year. CONCLUSION: Laser‐assisted subepithelial keratectomy improved visual acuity in pediatric hyperopia with or without associated hyperopic anisometropic amblyopia. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Plant Proteins with Antiviral Activity Against Human Immunodeficiency Virus

Human Immunodeficiency Virus (HIV), the etiological agent of acquired immunodeficiency syndrome (AIDS), is a member of the lentiviruses, a subfamily of retroviruses. Unlike other retro-oncoviruses, HIV is not known to cause cancer in humans and other animals, but it does present a formidable challenge to the host. HIV integrates its genetic information into the genome of the host. The viral genome contains many regulatory elements that allow the virus to control its rate of replication in both resting and dividing cells. Most importantly, HIV infects and invades cells of the immune system and renders the patient susceptible to opportunistic infections and neoplasms.