Ronald J Smith

DIFFUSE LAMELLAR KERATITIS: A NEW SYNDROME IN LAMELLAR REFRACTIVE SURGERY

OBJECTIVE This study aimed to describe a syndrome that the authors call diffuse lamellar keratitis that follows laser in situ keratomileusis (LASIK) and related lamellar corneal surgery. DESIGN Noncomparative case series and record review. PARTICIPANTS Thirteen eyes of 12 patients in whom infiltrates developed in the interface after lamellar refractive surgery were studied. INTERVENTION Topical antibiotics or corticosteroids or both were administered. MAIN OUTCOME MEASURES Corneal infiltrate appearance, focality, location, and clinical course were measured. RESULTS Patients presented between 2 and 6 days after surgery with pain, photophobia, redness, or tearing. Ten cases directly followed either myopic keratomileusis or LASIK. Three cases followed enhancement surgery without the use of a microkeratome. All 13 cases had infiltrates that were diffuse, multifocal, and confined to the flap interface with no posterior or anterior extension. The overlying epithelium was intact in each case. Cultures were negative in the two cases cultured. Ten eyes were treated with antibacterial agents; two eyes had fluorometholone four times daily added to the routine postoperative antibacterial regimen, and one eye had the antibacterial agent discontinued and was treated with topical fluorometholone alone. All infiltrates resolved without sequelae. CONCLUSIONS A distinct syndrome of unknown cause of noninfectious diffuse infiltrates in the lamellar interface is described. It can be distinguished from infectious infiltrates by clinical presentation and close follow-up. Patients with the syndrome should be spared the more invasive treatment of infectious keratitis.

Postoperative Inflammation, Microbial Complications, and Wound Healing Following Laser in situ Keratomileusis

Although the biology of corneal wound healing is only partly understood, healing after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) differs in many respects, and the mechanisms appear to be differently controlled. There is less of an inflammatory and healing response after LASIK, but a longer period of sensory denervation. The cellular, molecular, and neural regulatory phenomena associated with postoperative inflammation and wound healing are likely to be involved in the adverse effects after LASIK, such as flap melt, epithelial ingrowth, and regression. Interface opacities in the early postoperative period include diffuse lamellar keratitis (DLK), microbial keratitis, epithelial cells, and interface opacities. Diffuse lamellar keratitis (sands of the Sahara syndrome) describes an apparently noninfectious diffuse interface inflammation after lamellar corneal surgery probably caused by an allergic or a toxic inflammatory reaction. Noninfectious keratitis must be distinguished from microbial keratitis to avoid aggressive management and treatment with antimicrobial drugs. Microbial keratitis is a serious complication after LASIK, but a good visual outcome can be achieved following prompt and appropriate treatment.

Lens opacities after posterior chamber phakic intraocular lens implantation

PURPOSE To describe a case series to determine the incidence of lens opacities after posterior chamber phakic intraocular lens (IOL) implantation (STAAR Surgical, Monrovia, CA) for very high ametropias. DESIGN Retrospective, noncomparative, interventional case series. PARTICIPANTS Fourteen eyes of 170 consecutive eyes with high ametropias in whom lens opacities developed after posterior chamber phakic IOL implant (PCPIOL). INTERVENTION Posterior chamber phakic intraocular lens implant. MAIN OUTCOME MEASURES Lens opacity appearance, localization, and clinical course. RESULTS Fourteen eyes developed lens opacities 125 +/- 116 days after phakic IOL implant. All eyes had anterior subcapsular opacities, and two eyes also developed nuclear sclerosis. The anterior opacities did not extend posteriorly within the lens, and there were no posterior subcapsular cataracts. Seventy-one percent of opacities were first seen </=3 months, and 86% were seen </=7 months postoperatively. Seventy-nine percent of opacities were seen in the first or second implants of surgeons being trained; 19% of the first 16 cases and 0% of the next 43 cases of one surgeon developed opacities. Mean follow-up after opacity diagnosis was 9.1 +/- 6.8 months. Nine of the 14 (64%) opacities were asymptomatic. Two eyes developed nocturnal glare, with no loss of best-corrected visual acuity (BCVA) and one had loss of BCVA. Two additional eyes with both nuclear sclerotic and anterior subcapsular lens opacities had visual symptoms and/or loss of BCVA and underwent phakic IOL explantation, cataract extraction by phacoemulsification, and PCPIOL implant with good visual outcome. In the entire series, 5 of 170 (2.3%) implantations had symptomatic opacities in which 111 implantations were the first or second case of the implanting surgeon. CONCLUSIONS Lens opacities are a potential complication of phakic IOL implantation. Most lens opacities were first seen in the early postoperative period and were most likely due to surgically induced trauma. The anterior subcapsular type was most common and tended not to be rapidly progressive during the follow-up period. The presence of nuclear sclerotic cataract was visually significant and progressive. Long-term follow-up is warranted to evaluate the rate of progression and course of lens opacities after phakic IOL implant surgery.

Recent advances in customising cataract surgery

Cataract surgery has advanced a lot over the years. This review describes the latest techniques and how they are used to customise the surgery to the needs of the individual patient Cataract is an important cause of visual impairment worldwide. In the United Kingdom, 30% of people aged over 65 have visually impairing cataract (that is, Snellen visual acuity of less than 6/12 attributable to a lens opacity) in one eye or both eyes.1 (See table A on bmj.com for risk factors.) A visual acuity of 6/12 is below the legal vision requirement to drive in the United Kingdom, which approximates to a visual acuity of 6/10, and evidence indicates that cataract surgery may even decrease the incidence of road traffic crashes among people over 65.2 The NHS does approximately 200 000 cataract operations annually, making this one of the most common surgical procedures in the country.3 Despite this, 88% of people with treatable visual impairment from cataract are not in contact with any eye healthcare services, which represents a very large potential healthcare need.1 The fundamental aim of cataract surgery, the removal of the opacified natural lens to improve vision, has remained the same for hundreds of years. However, the way in which this is achieved and the expectations of the people having the surgery have altered drastically (table 1). Here we give an overview of some of the advances that allow cataract surgery to be customised for each patient. We discuss the process that patients go through from their first meeting with an ophthalmologist, through the preoperative assessment, to the actual surgery itself and beyond to the appraisal of the results of that surgery. The visual potential of the patient can be realised in many different ways, and when looked at in this context …

Laser in situ keratomileusis and photorefractive keratectomy for residual refractive error after phakic intraocular lens implantation.

PURPOSE To determine the visual and refractive outcome of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) in eyes with prior posterior chamber phakic intraocular lens implantation for high myopia. METHODS We studied a series of 37 consecutive eyes of 31 patients who underwent LASIK or PRK for residual refractive error following collamer posterior chamber intraocular lens (IOL) (Staar Surgical Implantable Contact Lens) implantation into a phakic eye. Twenty-eight eyes had LASIK and nine eyes had PRK. Mean follow-up was 8.1 +/- 4.7 months after laser ablation (range, 3 to 18 mo). RESULTS The preoperative mean spherical equivalent refraction prior to phakic posterior chamber IOL implantation was -17.74 +/- 4.89 D (range, -9.75 to -28.00 D). Following phakic IOL implantation and prior to LASIK or PRK, mean spherical equivalent refraction was -2.56 +/- 2.34 D (range, -0.25 to -8.75 D). One month following LASIK or PRK, mean spherical equivalent refraction was -0.24 +/- 0.52 D (range, -1.50 to +1.50 D), 3 months following LASIK or PRK, mean spherical equivalent refraction was -0.19 +/- 0.50 D (range, -1.50 to +1.00 D). The refraction was within +/-1.00 D of emmetropia in 36 eyes (97.2%) and within +/-0.50 D in 31 eyes (83.7%). Three eyes developed anterior subcapsular opacities several weeks after laser ablation, one eye developed macular hemorrhage 4 weeks after laser ablation, and one eye had corticosteroid induced ocular hypertension. CONCLUSIONS LASIK or PRK can be used to treat the residual refractive error following posterior chamber phakic IOL implantation.

Predictability of spherical photorefractive keratectomy for myopia1

Abstract Objective This study aimed to examine the effects of purely spherical excimer laser photorefractive keratectomy (PRK) for myopia. Design Consecutive case series. Participants A total of 3218 eyes with a mean preoperative mean spherical equivalent (MSE) of −3.75 diopters (D) ± 1.73 D standard deviation (SD) (range, −1.00 D to −11.88 D) underwent PRK with a Nidek EC-5000 excimer laser. Eyes were divided into groups based on the degree of preoperative myopia in 1 D steps Intervention All eyes underwent PRK with a Nidek EC-5000 excimer laser. Main outcome measure Visual and refractive outcome of PRK treatment was measured. Results After a mean follow-up period of 52.6 weeks (range, 26–150 weeks), the final MSE was −0.07 D (±0.68 D) (range, −5.50 D to +4.50 D). Of the 3218 eyes, 2919 (90.7%) were within 1.00 D of emmetropia, and 3038 (94.4%) of eyes had an uncorrected visual acuity of 20/40 or better, with 1886 (58.6%) achieving 20/20 or better visual acuity. Eyes in the lower preoperative myopia groups had a greater chance of attaining 20/40 unaided visual acuity than those in the higher groups (e.g., 98.3% of the −2D group and 53.6% of the −9D group achieved 20/40 unaided visual acuity). Overall, mean postoperative haze was 0.29 ± 0.39 SD (scale, 0–3), and 29 eyes (0.9%) lost 0.3 or more logarithm of the minimum angle of resolution (LogMAR) unit of best-corrected visual acuity. Conclusions Excimer laser PRK is an effective treatment for myopia of up to −9.00 D. The outcome parameters are less predictable for eyes with greater than −9.00 D of myopia.

Treatment of topographic central islands following refractive surgery

Purpose: To evaluate the safety and efficacy of using central reablation to treat topographic central islands following photorefractive keratectomy (PRK), myopic keratomileusis in situ, and laser in situ keratomileusis (LASIK). Setting: Department of Ophthalmology, Stanford University School of Medicine, Stanford, and Jules Stein Eye Institute, Los Angeles, California, USA. Methods: Central reablation was performed on eight eyes with clinically significant topographic central islands after refractive surgery. Two eyes developed central islands after PRK, five eyes after LASIK, and one eye after myopic keratomileusis in situ. A clinically significant topographic central island was defined as an area of steepening of at least 3.0 diopters by at least 1.5 mm in diameter documented by computerized videokeratography. Reablation was tailored to each eye based on the diameter and power of the topographic central island using the Munnerlyn formula. Results: All eyes experienced a reduction or elimination of the topographic central islands following central reablation. Six eyes experienced an improvement in uncorrected visual acuity, and all eyes returned to within one line of their preoperative level of best spectacle‐corrected visual acuity 1 month after the procedure. Conclusion: Topographic central islands following PRK, myopic keratomileusis in situ, and LASIK can be effectively treated using the excimer laser. Poor predictability of the refractive effect of central reablation may be the limitation of this treatment modality.

Predictability and outcomes of photoastigmatic keratectomy using the Nidek EC-5000 excimer laser.

Purpose: To evaluate the effect of astigmatic correction on the accuracy of the myopic and astigmatic correction in patients having photorefractive astigmatic keratectomy (PARK) and in those having photorefractive keratectomy (PRK). Setting: Specialist excimer laser refractive clinic. Methods: This prospective consecutive case series comprised 6097 eyes with a preoperative mean spherical equivalent (MSE) of –4.63 diopters (D) ± 1.95 (SD) (range –0.75 to –13.00 D) and a mean cylinder of –1.13 ± 0.73 D (range –0.50 to –6.00 D) having PARK with a Nidek EC‐5000 excimer laser. Visual and refractive outcomes were assessed 12 months postoperatively and compared with those in 3004 eyes that had spherical PRK. Results: At 12 months, the MSE was –0.02 ± 0.79 D and the mean cylinder was –0.49 ± 0.47 D in the PARK group; the MSE was −0.07 ± 0.66 D in the PRK group. An MSE within ±0.05 D of emmetropia was achieved by 69.8% and within ±1.00 D, by 87.9%. The uncorrected visual acuity (UCVA) was 20/20 or better in 42.6% and 20/40 or better in 91.2%. Statistical significance (P < .001, analysis of variance) was achieved for MSE, sphere, cylinder, haze, and visual acuity (best corrected [BCVA] and UCVA) based on the preoperative cylinder. The loss of BCVA varied from 1.1% to 5.8% depending on the degree of astigmatism treated. Accuracy varied with the attempted myopic correction and the attempted astigmatic correction. Conclusions: Excimer laser PARK was an effective treatment for compound myopic astigmatism, but predictability decreased and complications increased as the attempted astigmatic correction increased.

Simplified technique for suturing a temporary keratoprosthesis for pars plana vitrectomy

PURPOSE To describe an efficient technique for suturing a Landers wide-field temporary keratoprosthesis for intraocular surgery in an eye with an opaque cornea. METHODS Two sutures were preplaced at partial thickness into corneal stroma parallel to the corneoscleral limbus. Suture ends were placed through corresponding holes in the keratoprosthesis and tied. RESULTS The temporary keratoprosthesis was held firmly in place with two sutures and provided clear visualization for extensive intraocular surgery. CONCLUSION The preplaced two-suture technique for securing a temporary keratoprosthesis to the globe decreased the time that the globe was open.

Effect of an Elliptical Optical Zone on Outcome of Photoastigmatic Refractive Keratectomy

BACKGROUND This study presents the effect of an elliptical optical zone on the accuracy of correction of astigmatism in patients undergoing photorefractive astigmatic keratectomy (PARK) for myopic astigmatism. METHODS We reviewed a consecutive case series of 102 eyes that underwent PARK with a Nidek EC-5000 excimer laser by a single surgeon. Group A consisted of 50 eyes treated using a circular optical zone of 6.5 mm x 6.5 mm with a 7.5-mm x 7.5-mm transition zone. Group B consisted of 52 eyes treated using an elliptical optical zone of 5.5 mm x 6.5 mm with a 6.5-mm x 7.5-mm transition zone. Refraction was measured preoperatively and postoperatively, and vector analysis was used to study the change in astigmatism induced by surgery. RESULTS Mean correction index improved from 75% in Group A to 100% in Group B. Mean angle of error was reduced from 15.8 degrees in Group A to 7.5 degrees in Group B. Hyperopic shift was reduced from +0.70 D in Group A to +0.20 D in Group B. CONCLUSIONS Excimer laser photorefractive astigmatic keratectomy using an elliptical optical zone improved the correction index for astigmatic change and reduced the mean angle of error. An elliptical optical zone is more effective than the circular optical zone for the treatment of astigmatism in patients with compound myopic astigmatism.