Joseph Colin

Correcting keratoconus with intracorneal rings

PURPOSE To evaluate the potential of intrastromal corneal ring technology (Intacs, KeraVision) to correct keratoconus without central corneal scarring. SETTING Department of Ophthalmology, Brest University Hospital, Brest, France. METHODS In this prospective, noncomparative, interventional case series, Intacs segments were implanted in 10 keratoconic eyes with clear central corneas and contact lens intolerance after corneal pachymetry was checked. Segment thicknesses varied based on corneal topography analysis. RESULTS No intraoperative complications occurred. The mean follow-up was 10.6 months. Postoperative results revealed a reduction in astigmatism and spherical correction and an increase in topographical regularity and increased uncorrected visual acuity. CONCLUSION Intacs technology can reduce the corneal steepening and astigmatism associated with keratoconus.

INTACS inserts for treating keratoconus: One-year results

OBJECTIVE To evaluate the use of INTACS micro-thin prescription inserts (Kera Vision, Inc., Fremont, CA) for the treatment of keratoconus. DESIGN Prospective, nonrandomized (self-controlled) comparative trial. PARTICIPANTS/INTERVENTION Ten patients from our prospective clinical study who had completed 12 months of follow-up were evaluated. All patients had keratoconus with clear central corneas and were contact lens intolerant. After reviewing corneal pachymetry and topography of individual patients, INTACS inserts of 0.45-mm thickness were placed in the inferior cornea to lift the cone and INTACS of 0.25-mm thickness were inserted superiorly to counterbalance and flatten the overall anterior corneal surface. MAIN OUTCOME MEASURES Differences between preoperative and postoperative uncorrected visual acuity, best spectacle-corrected visual acuity, manifest refraction, and keratometry values were statistically assessed. Changes in corneal ectasia were evaluated by reviewing corneotopographic maps. RESULTS No intraoperative complications occurred in this series of patients. Spherical equivalent error and refractive astigmatism were reduced with INTACS inserts treatment. Postoperative month 12 uncorrected visual acuity (logarithm of the minimum angle of resolution [logMAR] mean, 0.35, standard deviation [SD], 0.16 [approximately 20/50, approximately 2 lines]) was significantly better than preoperative (logMAR mean, 1.05; SD, 0.33 [approximately 20/200, approximately 3 lines]; P <or=0.05). Average best spectacle-corrected visual acuity at postoperative month 12 was improved by approximately two lines compared with baseline (logMAR mean, 0.22; SD, 0.12 [approximately 20/32, approximately 1 line]; logMAR mean, 0.38; SD, 0.13 [approximately 20/50, approximately 1 line], respectively). Topographic corneal shape (size and height of the cone) was improved for all subjects after insert placement. CONCLUSIONS INTACS micro-thin prescription inserts seem to provide a viable method for treating clear corneal keratoconus for patients who are contact lens intolerant. The corneal steepening and astigmatism associated with keratoconus were reduced, and visual acuity was improved with treatment in almost all eyes.

Correlations between corneal hysteresis, intraocular pressure, and corneal central pachymetry

PURPOSE: To analyze the correlation between corneal hysteresis (CH) measured with the Ocular Response Analyzer (ORA, Reichert) and ultrasonic corneal central thickness (CCT US) and intraocular pressure measured with Goldmann applanation tonometry (IOP GA). SETTING: Bordeaux 2 University, Ophthalmology Department, Bordeaux, France. METHODS: This study comprised 498 eyes of 258 patients. Corneal hysteresis, corneal resistance factor (CRF), and IOP corneal‐compensated (IOPcc) were provided by the ORA device; CCT US and IOP GA were also measured in each eye. The study population was divided into 5 groups: normal (n = 122), glaucoma (n = 159), keratoconus (n = 88), laser in situ keratomileusis (LASIK) (n = 78), and photorefractive keratectomy (n = 39). The Pearson correlation was used for statistical analysis. RESULTS: Corneal hysteresis was not strongly correlated with IOP or CCT US. The mean CH in the LASIK (8.87 mm Hg) and keratoconus (8.34 mm Hg) groups was lower than in the glaucoma (9.48 mm Hg) and normal (10.26 mm Hg) groups. The lower the CH, the lower its correlation with IOPcc and IOP GA. A CH higher than the CRF was significantly associated with the keratoconus and post‐LASIK groups. CONCLUSIONS: Corneal hysteresis, a new corneal parameter, had a moderate dependence on IOP and CCT US. Weaker corneas could be screened with ORA parameters, and low CH could be considered a risk factor for underestimation of IOP. The CCT US should continue to be considered a useful parameter.

Retinal detachment after clear lens extraction for high myopia: Seven-year follow-up

Abstract Objective To prospectively evaluate the incidence of complications, particularly retinal detachment, 7 years after clear lens extraction (CLE) for myopia greater than −12 diopters (D). Design Extended follow-up of noncomparative case series. Participants Fifty-two eyes of 30 patients with preoperative myopia greater than −12 D, best-corrected visual acuity (BCVA) of 20/100 or better, and intolerance of contact lenses. Intervention Patients with lattice degeneration, retinal tear, or hole underwent photocoagulation before CLE. The authors performed phacoemulsification through a 3.2-mm-wide incision using primary irrigation and aspiration, widened the incision to 6.5 mm, and implanted a one-piece polymethyl methacrylate intraocular lens (IOL). Main outcome measures The BCVA, uncorrected visual acuity (UCVA), stability of spherical equivalent (SE), neodymium:YAG (Nd:YAG) capsulotomy rate, and complications (especially retinal detachment). Results At 7 years, the SEs of 29 eyes (59.1%) were within ±1.0 D of emmetropia and 42 eyes (85.7%) were within ±2.0 D. Mean SE was −1.01 D (±0.94). At 7 years, mean UCVA was 20/80 compared with 20/66 at 1 year. BCVA and UCVA were better in eyes with open capsules versus intact capsules. During the 7 years, 30 eyes (61.2%) required capsulotomy for opacification. Mean time for capsulotomy was 48.4 months after CLE. The authors performed ten argon laser retinal treatments after surgery, with all but one in the first postoperative year. The overall incidence of posterior vitreous detachment was 16.3%. The incidence of retinal detachment during the 7 years was 4 of 49 eyes, or 8.1% (vs. 2.0% at 4 years). One patient had bilateral retinal detachments. Conclusion Despite advances in surgical technique, retinal detachment remains a major concern after CLE for high myopia. In the authors’ series, the incidence of retinal detachment after CLE was nearly double that estimated for persons with myopia greater than −10 D who do not undergo surgery. Although CLE has advantages, including rapid and predictable visual rehabilitation, stable refraction, the ability to replace the IOL, and often superb optical quality with no irregular astigmatism, it is invasive and can result in severe vision loss. Long and continuous follow-up of the outcomes of CLE for high myopia is absolutely necessary before the authors can consider CLE as a routine option for patients with high myopia.

Angle-fixated Anterior Chamber Phakic Intraocular Lens for Myopia of -7 to -19 Diopters

PURPOSE To assess the safety and efficacy of a second generation, anterior chamber phakic intraocular lens (Baikoff Model ZB5M) in patients with high myopia. METHODS One hundred and twenty-one patients (134 eyes) with myopia of -7.00 to -18.80 D were implanted with the ZB5M lens and followed for 18 to 52 months; the number of eyes evaluated was: 6 months (104 eyes), 1 year (91 eyes), 18 months (78 eyes), 2 years (68 eyes), and 3 years (35 eyes). RESULTS Postoperative spherical equivalent refraction averaged -1.00 D and the error in refractive correction (achieved minus intended) averaged -0.40 D during the first 2 years, increasing -to -1.30 D refraction and -0.60 D error in refractive correction at 3 years. At 2 years, approximately 40% of eyes had a spherical equivalent refraction within +/-0.50 D, and 65% within +/-1.00 D. The uncorrected distance visual acuity was 0.048 at baseline and 0.5 at 3 years; near visual acuity was 0.21 at baseline and approximately 0.7 over the 3 years of follow-up. Spectacle-corrected distance visual acuity at baseline was 0.54; it improved to 0.7. Near visual acuity was 0.65 at baseline and it improved to approximately 0.75. Endothelial cell counts in the central and peripheral cornea were reduced by an average 3.3% at 6 months, declining an additional 1% to 2% over the remaining follow-up period. Regression analyses indicated that most of the endothelial cell loss was due to surgery. Additional complications included halos/glare in 37 of 133 eyes (27.8%) and iris retraction with pupillary ovalization in 30 of 133 eyes (22.6%). The intraocular lens was exchanged in four of 133 eyes (3.0%) and removed in three of 133 eyes (2.3%), the latter because of halos (one eye) and a flat anterior chamber with severe inflammation (two eyes). CONCLUSIONS Implantation of the Baikoff ZB5M lens in the anterior chamber of phakic eyes significantly reduced high myopia and produced a stable refractive outcome over the 3 years, accompanied by marked improvement in uncorrected distance visual acuity and minimal, non-progressive damage to the corneal endothelium. Frequent complications included pupillary ovalization and halos/glare. Improvements in accuracy of IOL power calculations are needed.

Corneal collagen crosslinking in progressive keratoconus: multicenter results from the French National Reference Center for Keratoconus.

PURPOSE: To report refractive, topographic, and biomechanical outcomes, efficiency, and safety of corneal collagen crosslinking (CXL) 1, 3, 6, and 12 months after treatment. SETTING: National Reference Centre for Keratoconus, Bordeaux and Toulouse, France. DESIGN: Case series. METHODS: This retrospective uncontrolled double‐center study comprised eyes with progressive keratoconus. Uncorrected distance visual acuity, corrected distance visual acuity (CDVA), corneal pachymetry, endothelial cell count, and corneal hysteresis and corneal resistance factor were evaluated at baseline and at 1, 3, 6, and 12 months. RESULTS: One hundred forty‐two eyes were enrolled in the study. At 6 months, the CDVA had stabilized in 53 eyes (48.1%), improved in 36 eyes (32.7%), and decreased in 18 eyes (16.3%). At 12 months, the CDVA had stabilized in 31 eyes (47.6%), improved in 26 eyes (40.0%), and decreased in 8 eyes (12%). At 6 months, keratoconus progression had stopped in 51 eyes (49.03%) and the maximum keratometry (K) value had decreased by more than 1.0 diopter (D) in 37 eyes (35.5%); it continued to progress in 16 eyes (15.3%). At 12 months, keratoconus progression had stopped in 42 eyes (68.8%) and the maximum K value had decreased by more than 2.0 D in 13 eyes (21.3%). The complication rate with loss of vision was 3.5%. CONCLUSIONS: Ultraviolet‐A light associated with riboflavin CXL is an efficient procedure to stabilize and improve progressive keratoconus. The results reinforce previous studies highlighting the efficacy and safety of the procedure. A large prospective randomized clinical trial is needed. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Clear Lensectomy and Implantation of Low-power Posterior Chamber Intraocular Lens for the Correction of High Myopia

BACKGROUND Although a variety of surgical procedures to treat high myopia have been studied, no consensus exists on the optimum procedure. Clear lensectomy with implantation of a posterior chamber intraocular lens has been regarded as risky, due to the higher incidence of retinal detachment in highly myopic eyes. METHODS The authors performed surgery and evaluation over 1 year in 52 eyes in which prophylactic retinal treatment, clear lensectomy, and posterior chamber intraocular lens implantation were used to treat high myopia of 12 diopters (D) or greater. RESULTS Before lens extraction, 31 eyes underwent argon laser photocoagulation. Over the 1-year period, three additional eyes were treated, and six eyes that had been treated preoperatively received additional treatment. No cystoid macular edema, retinal detachment, or persistent corneal edema was observed in this series. At 1 year, 88.5% of the group achieved corrected visual acuity of 20/40 or better, compared with 75% preoperatively. Uncorrected visual acuity of 20/100 or better was achieved by 84.6% of the group. The mean postoperative spherical equivalent was -0.86 +/- 0.84 D. CONCLUSION The refractive objectives were achieved. Complications reported previously with clear lensectomy were not experienced in this group. The low incidence of complications can be attributed to the short follow-up and probably in part to the prophylactic retinal treatment, combined with the phacoemulsification procedure for lens extraction. Longer follow-up is needed to fully assess the complications. Properly randomized prospective clinical trials will be able to fully assess the benefits and risks of prophylactic retinal treatment and clear lens extraction with posterior intraocular lens implantation. This series can help in evaluating this surgical procedure.

Damage to the corneal endothelium from anterior chamber intraocular lenses in phakic myopic eyes.

The use of minus power anterior chamber intraocular lenses to correct myopia in phakic eyes has been demonstrated previously to produce a more accurate and predictable correction than corneal refractive surgery techniques. We have examined 15 such eyes by specular microscopy and 10 such eyes by Scheimpflug slit-lamp micrography. One year after surgery, in 5 (36.3%) eyes, there was a decrease of more than 20% in the central endothelial density. Paracentral endothelial damage was present in 13 eyes (86.6%). On the specular micrograph, this damage appeared as an overall decrease in the number of the cells, abnormal cell shape with marked pleomorphism, dark zones, and acellular zones that corresponded to endothelial defects. The slit-lamp anterior segment measurements showed a distance between the edges of the IOL optic and the endothelium which ranged from 0.71 to 1.50 mm. We discuss the criteria for intraocular lens removal.

Screening of Forme Fruste Keratoconus with the Ocular Response Analyzer

PURPOSE To evaluate the performance of the Ocular Response Analyzer (ORA) in the screening of forme fruste keratoconus (FFKc). METHODS A retrospective comparative study was conducted involving 180 eyes. ORA preoperative data were analyzed for 125 normal control eyes (64 patients) undergoing laser in situ keratomileusis (LASIK) without corneal ectasia after 24 months of follow-up and 55 case eyes with unilateral keratoconus from a database (BCVA of 1.0, KISA index <60%). All eyes were matched in four groups of central corneal thickness (CCT): group 1, <500 microm; group 2, 500 to 539 microm; group 3, 540 to 579 microm; and group 4 >580 microm. Corneal hysteresis (CH), the corneal resistance factor (CRF), the air pressure curve, and the infrared signal were compared between FFKc and normal eyes in each group. RESULTS The mean CH was 9.1 +/- 1.8 mm Hg for FFKc and 10.3 +/- 1.9 mm Hg for control eyes (P < 0.001), and the mean CRF was 9.2 +/- 1.8 and 11.1 +/- 2 mm Hg (P < 0.001), respectively. Sensitivity in each group was as follows: group 1, CH < 9.5 mm Hg (91%) and CRF < 9.5 mm Hg (81%); group 2, CH < 10.5 mm Hg (91%) and CRF < 10 mm Hg (87%); group 3, CH < 11.5 mm Hg (79%) and CRF < 11 mm Hg (74%); group 4 had two cases of FFKc, and the difference was not significant. Air pressure levels at inward and outward applanation and the maximum air pressure level were significantly lower and shorter in time in FFKc (P < 0.001), whereas the shape of the infrared signal was more variable. CONCLUSIONS The ORA provides additional information in the screening of FFKc, with an accurate analysis of the corneal biomechanical properties according to CCT, air pressure, and infrared curves.

Comparison of the efficacy and safety of valaciclovir and acyclovir for the treatment of herpes zoster ophthalmicus.

OBJECTIVE To compare the efficacy and safety of valaciclovir and acyclovir in immunocompetent patients with herpes zoster ophthalmicus. DESIGN A multicenter, randomized, double-masked study. PARTICIPANTS One hundred ten immunocompetent patients with herpes zoster ophthalmicus diagnosed within 72 hours of skin eruption were treated; 56 were allocated to the valaciclovir group and 54 to the acyclovir group. METHODS Patients randomized to the valaciclovir group received two 500-mg tablets of valaciclovir three times daily and one tablet of placebo twice daily. Patients in the acyclovir group received one 800-mg tablet of acyclovir five times daily and one tablet of placebo three times daily for 7 days. MAIN OUTCOME MEASURES Main outcome measures included the frequency, severity, and duration of ocular complications, patient reports of zoster-associated pain, and the outcome of skin lesions. Tolerance was also assessed on the incidence and types of adverse effects and changes in laboratory parameters. The analysis was mainly descriptive and performed on an intent-to-treat basis. RESULTS Ocular complications of herpes zoster ophthalmicus were similar in the valaciclovir and acyclovir treatment groups. The main complications were conjunctivitis (54% and 52%, respectively), superficial keratitis (39% and 48%, respectively for punctate keratitis; 11% in each group for dendritic keratitis), stromal keratitis (13% in each group), and uveitis (13% and 17%, respectively). The long-term outcomes of these ocular complications were favorable and similar in both treatment groups. Pain duration and severity and outcome of skin lesions were similar between groups. Most patients reported prodromal pain. After 1 month, 25% of patients in the valaciclovir group and 31% in the acyclovir group still reported pain. The percentage of patients experiencing postherpetic neuralgia decreased during follow-up. The tolerance to acyclovir and valaciclovir was comparable and considered good. The most frequent adverse events were vomiting and edema of the eyelids or face (3%-5%). Three serious adverse events not linked to the study drugs occurred. CONCLUSIONS Valaciclovir is as effective as acyclovir in preventing ocular complications of herpes zoster ophthalmicus, including conjunctivitis, superficial and stromal keratitis, and pain. Tolerability of the two drugs is similar, but the dosing schedule of valaciclovir is simpler.