Corneal collagen cross-linking for ectasia after LASIK and photorefractive keratectomy: long-term results.

PURPOSE: To report the long-term results of corneal collagen cross-linking (CXL) in ectasia after LASIK and photorefractive keratectomy (PRK). DESIGN: Retrospective, interventional cases series. PARTICIPANTS: Twenty-six eyes of 26 patients (18 male, 8 female) with postoperative ectasia after LASIK (23 eyes) and PRK (3 eyes) were included with a mean age of 35 ± 9 years at the time of treatment and a mean follow-up of 25 months (range, 12-62 months). METHODS: All consecutive patients treated with CXL for progressive ectasia after LASIK or PRK at the Institute for Refractive and Ophthalmic Surgery, Zurich, Switzerland between 2004 and 2010 were included. MAIN OUTCOME MEASURES: Corrected distance visual acuity (CDVA), maximum keratometry readings (K(max)), minimum radius of curvature (R(min)), and 6 corneal topography indices were assessed in this study. RESULTS: Mean CDVA before CXL was 0.5 logarithm of the minimum angle of resolution (logMAR) units, which improved to a mean of 0.3 logMAR units (P<0.001). Corrected distance visual acuity improved 1 line or more in 19 cases and remained unchanged in 7 patients. Mean K(max) after CXL of 50.9 ± 4.9 diopters (D) was significantly lower (P<0.001) than mean pre-CXL K(max) of 52.8 ± 5 D. The R(min) after CXL was increased significantly (P = 0.006), whereas the index of surface variance (P = 0.03), the index of vertical asymmetry (P = 0.04), the keratoconus index (P = 0.03), and the central keratoconus index (P = 0.016) were reduced significantly. CONCLUSIONS: Ectasia after LASIK and PRK was arrested by CXL with stabilization or improvement of CDVA and K(max) after a mean follow-up of 25 months. There were improvements in 4 topography indices, suggesting a more regular corneal surface.

Are ocular injection anesthetic blocks obsolete? Indications and guidelines.

PURPOSE OF REVIEW: In this era of topical anesthesia for ocular surgery, anesthetic ocular blocks are still important when profound anesthesia and akinesia are required. Although injection ocular blocks, retrobulbar and peribulbar anesthesia, have been supplanted for most ocular surgery in many centers by sub-Tenon's irrigation block because of its superior safety profile, still worldwide, injection blocks remain popular. RECENT FINDINGS: We present here the results of a survey of the literature published over the last 5 years to assess current international preferences for ocular anesthesia injection blocks. We discuss the reasons why sub-Tenon's anesthesia is not more universally popular and advocate for its greater acceptance because of safety. Specific narrow indications for performing injection ocular blocks are presented. Also, guidelines for performing retrobulbar anesthesia which reduce the risk of serious ocular complications are provided as well as our rationale for preferring retrobulbar to peribulbar anesthesia. SUMMARY: Sub-Tenon's block should be performed in the operating theatre in preference to retrobulbar or peribulbar anesthesia except for limited indications. When injection ocular block is deemed necessary, we feel that retrobulbar anesthesia with the technique described may be safer than peribulbar anesthesia.

Posterior-assisted levitation in cataract surgery.

PURPOSE OF REVIEW: Posterior-assisted levitation (PAL) is a surgical maneuver for dealing with rupture of the posterior capsule or zonular dehiscence with threatened or actual subluxation of the nucleus or entire lens into the vitreous during phacoemulsification. PAL is often unknown or overlooked, especially by young or inexperienced surgeons. RECENT FINDINGS: The advantages of PAL are, first, that it often enables completion of phacoemulsification and intraocular lens placement without conversion to an open eye with nuclear expression and second, it prevents luxation of nucleus, nuclear fragments, or the lens into the vitreous avoiding the necessity for trans pars plana vitrectomy (TPPV)-lensectomy. PAL has recently been criticized by vitreoretinal surgeons as dangerous and to be avoided. However, there is no large series or controlled study showing that the PAL maneuver is associated with an excessive complication rate as compared to cases of nuclear or lens subluxation in the vitreous managed by TPPV-lensectomy with or without previous PAL. SUMMARY: PAL is a simple technique that can be extremely helpful. In cases in which the PAL maneuver is unsuccessful and in cases with complete luxation of nucleus or lens into the vitreous, the patient should be referred for TPPV-lensectomy.

Pediatric ocular rosacea.

A case of severe pediatric ocular rosacea was effectively treated after 2.5 years of misdiagnosis. A high index of suspicion should be maintained in children with ocular surface disease, with or without dermatologic rosacea, to correctly diagnose ocular rosacea and avoid morbidity and complications.

Feigned visual loss misdiagnosed as occult traumatic optic neuropathy: diagnostic guidelines and medical-legal issues.

The medical-legal problem of occult traumatic optic neuropathy diagnosed in patients who actually have feigned visual loss (malingering) is reviewed along with guidelines for suspecting and differentiating feigned visual loss from true traumatic optic neuropathy. We explain why we feel the term occult optic neuropathy is inappropriate and misleading, and the medical-legal consequences of this misdiagnosis are discussed.

Perceptual distortion in homonymous paracentral scotomas.

BACKGROUND: Cortical remapping after peripheral or central visual deafferentation alters visual perception, but it is unclear whether such a phenomenon impinges on areas remote from a scotoma. To investigate this question, we studied variations of perceptual spatial distortion in the visual field of patients with homonymous paracentral scotoma. METHODS: Two patients with right inferior homonymous paracentral scotoma were asked to describe their perception of a series of figures showing two isometric vertical lines symmetrically located on either side of a fixation point. In each figure, the fixation point varied by steps of 2 degrees along a hypothetical vertical line equidistant between the test lines. The lines subtended 20 degrees of visual angle, and the right line passed through the scotoma in both cases. Time for spatial distortion to manifest was recorded. RESULTS: Both subjects reported that the right line was perceived as shorter than the left one. The line shortening varied in magnitude with the distance of the fixation point from the end of the line and was more pronounced when the distance increased. Moreover, perceptual line shortening appeared 5-10 seconds after steady fixation, but values of shortening varied during the following 10 seconds. In addition, the right line appeared uninterrupted or slightly blurred in the scotoma region. CONCLUSIONS: These observations reflect long-range cortical reorganization after brain damage. Larger receptive fields in the periphery of the visual map could explain why perceptual shortening is more pronounced with increased eccentricity.

Results and safety profile of trainee cataract surgeons in a community setting in East Africa.

PURPOSE: To evaluate the results and safety profile of assistant medical officer ophthalmologists (AMO-O) performing cataract surgery in the last stage of their surgical training, before their appointment to local communities. METHODS: We retrospectively analyzed the records of patients who underwent cataract surgery by AMO-Os at Dar es Salaam, Comprehensive Community Based Rehabilitation for Tanzania Disability Hospital between September 2008 and June 2011. Surgical options were either extracapsular cataract extraction (ECCE) or manual small incision cataract surgery (MSICS), both with polymethylmethacrylate intraocular lens implantation. RESULTS: Four hundred and fourteen patients were included in the study. Two hundred and twenty-five (54%) underwent ECCE and 189 had MSICS. Mean logarithm of the minimum angle of resolution (logMAR) uncorrected visual acuity (UCVA) improved from 2.4 ± 0.6 preoperatively to 1.3 ± 0.8 1 week postoperatively (t-test, P < 0.001) and to 1.1 ± 0.7 3 months postoperatively (t-test, P < 0.001). Mean logMAR best-corrected visual acuity (BCVA) was 0.7 ± 0.5 1 week postoperatively and 0.6 ± 0.5 3 months postoperatively. There was no significant difference in mean logMAR UCVA (P = 0.7) and BCVA (P = 0.7) postoperatively between ECCE and MSICS. 89.5% achieved BCVA better than 6/60 and 57.3% better than 6/18 with a follow-up of 3 months. Posterior capsule rupture and/or vitreous loss occurred in 34/414 patients (8.2%) and was more frequent (P = 0.047) in patients undergoing ECCE (10.2%) compared with MSICS (5.3%). CONCLUSION: AMO-O cataract surgeons at the end of their training offer significant improvement in the visual acuity of their patients. Continuous monitoring of outcomes will guide further improvements in surgical skills and minimize complications.

Misdirected aqueous flow in rhegmatogenous retinal detachment: a pathophysiology update.

It is widely accepted that the origin of subretinal fluid in rhegmatogenous retinal detachment (RRD) is liquid vitreous and that posterior vitreous detachment (PVD) and associated retinal tears are caused by vitreoretinal traction from intra-ocular currents, contraction of collagen fibers, and gravity. These explanations, however, are incomplete. We present a new synthesis of experimental and clinical evidence, updating understanding of fundamental pathophysiological processes in RRD. Misdirected aqueous flow is shown to more convincingly explain the origin of subretinal fluid in clinical RRD, to be the most likely cause of acute PVD and retinal tear formation, and also to contribute to initial detachment of the retina at retinal tears. Misdirected aqueous flow in RRD is a pathophysiological process, rather than the "aqueous misdirection syndrome", and occurs without visible anterior chamber shallowing or acute glaucoma.

Phacolytic glaucoma: are there 2 forms?

We report a case of acute phacolytic glaucoma in which only protein was present in the anterior chamber without macrophages. We propose that this study represents a type of phacolytic glaucoma characterized by a hyperacute presentation caused by rapid leakage of degenerated lens proteins into the aqueous humor as opposed to a second type with a more gradual onset and with phacolytic macrophages in the aqueous humor resulting from an immunologic response to liquefied lens proteins. Thus, 2 forms, perhaps at ends of a spectrum of clinical manifestations of phacolytic glaucoma, may exist with distinct characteristics and pathophysiology.

Topiramate-induced acute bilateral angle closure and myopia: pathophysiology and treatment controversies.

PURPOSE: To discuss the unusual features of topiramate-induced acute angle closure glaucoma, its pathophysiologic mechanisms, and treatment controversies, and to report the first anterior segment optical coherence tomography (OCT) of this condition. METHODS: Literature review and case report with OCT findings. RESULTS: Topiramate-induced angle closure is usually bilateral and associated with acute myopia; the ocular pressure is often not very highly elevated. Ciliochoroidal detachment with ciliary body anterior rotation is typically present and was demonstrated easily in our case with anterior segment OCT. Pilocarpine exacerbates this condition and peripheral iridotomy is not indicated, nor is iridoplasty. Treatment consists of replacing topiramate with appropriate medication, strong cycloplegia, and topical steroids. CONCLUSIONS: It is important to recognize this form of acute secondary angle closure in order to treat it properly, avoiding harmful medication and unnecessary surgery.

Postoperative IOP is related to intrascleral bleb height in eyes with clinically flat blebs following deep sclerectomy with collagen implant and mitomycin.

AIM: To investigate the relationship between intrascleral bleb height and intraocular pressure (IOP) following deep sclerectomy with collagen implant (DSCI) and mitomycin C (MMC) in eyes with clinically flat blebs. METHODS: The records of 25 eyes of 22 consecutive patients presenting with clinically flat blebs following DSCI with MMC for primary or secondary open angle glaucoma were reviewed. Anterior segment optical coherence tomography (AS-OCT) scans were used to evaluate postoperative intrascleral bleb height and its relation to IOP control. Eyes requiring postoperative bleb manipulations, needling or goniopunctures were excluded. RESULTS: The mean age of the patients was 71.9+/-12.6 years, and the mean preoperative IOP was 25.3+/-5.6 mm Hg. The mean time of the AS-OCT examination from the operation was 8+/-4.9 months, and the mean IOP at that time was 13.8+/-4.2 mm Hg (p<0.001). All operated eyes manifested an intrascleral bleb with AS-OCT. The mean intrascleral bleb height was 0.58+/-0.16 mm. IOP and intrascleral bleb height were found to be inversely correlated (p<0.001, r=-0.626). None of the eyes had subconjuctival blebs, and 17/25 eyes showed microscopic conjuctival fluid collections. CONCLUSION: The authors report a positive inverse correlation between intrascleral bleb height and postoperative IOP in eyes presenting clinically flat blebs following DSCI with MMC, suggesting an important role for intrascleral filtration in lowering IOP. Further studies are warranted to evaluate this relationship at different postoperative time points and possibly with different types of implants.

Outflow facility in isolated porcine eyes after creation of an intrascleral canal by injection of stabilized hyaluronic acid.

PURPOSE: To investigate outflow facility in isolated porcine eyes after creation of an intrascleral canal by injection of stabilized, nonanimal, hyaluronic acid gel (NASHA; Q-Med AB, Uppsala, Sweden). METHODS: Outflow facility of 60 porcine eyes was measured after creation of an intrascleral canal into the anterior chamber by injection of NASHA gel using six different combinations of needle size (21, 23, and 27 gauge) and canal length (4.6 mm). Ten eyes were tested in each of the six subgroups and an additional 10 were control eyes. After cannulation of the anterior chamber and adjustment of the inflow rate to achieve a stable pressure of 10 mm Hg, an intrascleral channel was created by injection of NASHA gel. The inflow rate was then increased to achieve a stable pressure of 20 mm Hg and then again adjusted to maintain a stable pressure of 30 mm Hg. RESULTS: A significant increase in outflow facility was found between the control group and the NASHA gel-injected group (60 eyes) for both the 10- to 20-mm Hg and the 20- to 30-mm Hg pressure change (P < 0.001). Increase in outflow facility was independent of the canal lengths and the needle sizes used for both the 10- to 20-mm Hg (P = 0.82) and 20- to 30-mm Hg (P = 0.99) pressure change. CONCLUSIONS: A single ab externo intrascleral canal created by injection of NASHA gel increases the outflow facility in isolated porcine eyes. This is a potentially promising new technique for lowering intraocular pressure. It remains to be seen whether these positive results can be reproduced for significant periods in humans.