Late bilateral keratectasia after LASIK in a low myopic patient

PURPOSE: To report a rare case of late bilateral ectasia developing after LASIK for low myopia without preoperative risk factors. METHODS: A 21-year-old man underwent bilateral uneventful LASIK for low myopia of -2.75 diopters in both eyes. Preoperative corneal pachymetry was 531 microm in the right eye and 526 microm in the left eye. The total ablation depth was 46.8 microm in the right eye and 42.2 microm in the left eye. Preoperative corneal topography was normal and did not reveal forme fruste keratoconus. RESULTS: Twenty-four months postoperatively, the patient developed bilateral inferior keratectasia of +0.50 -3.00 x 72 degrees in the right eye and +1.00 -2.75 x 99 degrees in the left eye. CONCLUSIONS: Late keratectasia may follow LASIK for low myopia despite a thorough preoperative work-up.     

Marked discordance for myopia in female monozygotic twins

Female monozygotic twins aged 54 years discordant for myopia are reported. One twin presented with bilateral high myopia (right eye = -6.00/+0.50 x 5 degrees , left eye = -6.00/+0.50 x 45 degrees ) and her identical twin had no significant refractive error (right eye = -0.50/plano, left eye = -0.50/+0.75 x 40 degrees ). An explanation for the striking refractive discordance seen in this case report is yet to be determined.     

Development of unilateral corneal ectasia after PRK with ipsilateral preoperative forme fruste keratoconus

PURPOSE: To describe clinical and topographic features of keratectasia after photorefractive keratectomy (PRK) in a patient with abnormal preoperative topography. METHODS: A 25-year-old man underwent uneventful bilateral PRK for moderate myopia of -5.75 -1.75 x 95 in the right eye and -7.50 -1.25 x 80 in the left eye with best spectacle-corrected visual acuity (BSCVA) of 20/25 in both eyes. Preoperative corneal thickness was 500 microm in the right eye and 460 microm in the left eye. The total calculated ablation depth was 70 microm in the right eye and 100 microm in the left eye. Preoperative corneal topography revealed forme fruste keratoconus in the right eye with an inferior-superior ratio of 4. RESULTS: Five years postoperatively, the patient developed unilateral inferior keratectasia in the right eye with refraction of +0.50 -5.50 x 90, BSCVA of 20/100, and central corneal thickness of 481 microm with inferior corneal thickness of 374 microm. CONCLUSIONS: This case report adds to the growing body of evidence in the ophthalmic literature suggesting that patients with preoperative forme fruste keratoconus or early keratoconus may develop clinically significant progression of corneal ectasia after PRK.     

Corneal perforation during laser in situ keratomileusis after hyperopic electrothermal keratoplasty

PURPOSE: To report a corneal perforation during laser in situ keratomileusis (LASIK) after previous electrothermokeratoplasty. DESIGN: Interventional case report. METHODS: A 49-year-old man presented with primary hyperopia in the right eye and residual hyperopia after electrothermokeratoplasty in the left eye. His refraction was +4.00 in the right eye and +7.00 -3.00 x 135 degrees in the left eye, with a central pachymetry of 535 microm and 549 microm, respectively. Phacoemulsification with intraocular lens (IOL) insertion in the right eye and a two-step keratophacorefractive procedure with a piggyback IOL insertion and LASIK in the left eye were proposed. RESULTS: Postoperative refraction was -0.50 -0.50 x 150 degrees 20/20 in the right eye. Postphacoemulsification refraction was -4.75 -4.25 x 135 degrees in the left eye. Laser in situ keratomileusis was performed in the left eye, 4 months later, with uneventful astigmatic laser ablation. During the myopic ablation, a sudden outcome of aqueous humor in one of the temporal corneal scars was observed. CONCLUSIONS: Unpredictably thin areas after electrothermokeratoplasty may lead to unexpected corneal perforation during LASIK. The available pachymetry systems may be unreliable after electrothermal keratoplasty.     

Photorefractive keratectomy with mitomycin-C for the treatment of compound moderate myopia with astigmatism in buccal pemphigus vulgaris

We report a case of controlled buccal pemphigus vulgaris with compound moderate myopia with astigmatism that was treated with photorefractive keratectomy with mitomycin-C (PRK+MMC) in both eyes. The preoperative manifest refraction was -6.50 sphere and -5.5 -0.75 x 20 in the right eye and left eye, respectively, with a best corrected visual acuity of 10/10 in both eyes. Seven months after surgery, the uncorrected visual acuity was 10/10 in both eyes. The manifest refraction was 0.75 sphere and 0.50 -0.75 x 120 in the right eye and left eye, respectively. Haze was not detected in the follow-up examinations. Reepithelialization was complete 5 days after surgery in both eyes. The results show that PRK+MMC for compound moderate myopia with astigmatism in a patient with controlled pemphigus vulgaris may be an effective and safe treatment.     

Corneal decompensation after laser in situ keratomileusis in fuchs' endothelial dystrophy

PURPOSE: To report corneal decompensation after laser in situ keratomileusis (LASIK) in a patient with Fuchs' endothelial dystrophy.METHODS: Observational case report. RESULTS: A 47-year-old woman with cornea guttata without symptoms or findings of corneal edema had uneventful LASIK for -5.50 -0.50 x 150 in the right eye and -4.00 -1.25 x 170 in the left eye. Postoperatively, she developed corneal edema, with significant loss of best-corrected visual acuity in both eyes. Preoperative corneal thickness was 587 microm in the right eye and 549 microm in the left eye, measured by ultrasound pachymetry. These readings were 550 and 560 microm on day 67 postoperatively. Endothelial cell counts showed means of 1209 and 1661 cells/mm2 in the right and left eyes, respectively. CONCLUSION: Caution is suggested when considering LASIK in eyes with severe cornea guttata.     

Corneal ectasia after hyperopic LASIK

PURPOSE: To report two cases of corneal ectasia, which developed after hyperopic LASIK. METHODS: Preoperative pellucid marginal corneal degeneration was observed in patient 1. Patient 2 had no preoperative risk factors. RESULTS: Patient 1, a 47-year-old man, developed corneal ectasia in his right eye 6 months after unilateral hyperopic LASIK. Preoperative manifest refraction was +2.00 +1.50 x 178 in the right eye and +1.00 sphere in the left eye. Corneal thickness was 585 microm and 575 microm (right and left eye, respectively). Preoperative topography of the right eye demonstrated inferior steepening in the far periphery, suggestive of early pellucid marginal corneal degeneration. Patient 2, a 35-year-old man, developed corneal ectasia in his right eye > 3 years after bilateral LASIK. Preoperative manifest refraction was +2.50 sphere and +3.25 sphere (right and left eye, respectively), and corneal thickness was 556 microm in both eyes. Preoperative topography was normal in both eyes with no evidence of asymmetry, steepening, or irregularity. CONCLUSIONS: Corneal ectasia can occur after hyperopic LASIK in patients with or without recognized preoperative risk factors. Although uncommon, patients with pellucid marginal corneal degeneration can have hyperopic refractions and are at high risk for developing corneal ectasia after LASIK.     

Keratectasia after LASIK but not after PRK in one patient

PURPOSE: To report a case of keratectasia in a patient who underwent LASIK in the right eye and photorefractive keratectomy (PRK) in the left eye for correction of compound myopic astigmatism. METHODS: A 30-year-old man underwent LASIK in the right eye and PRK in left eye for refraction of -1.75 -1.50 x 48 degrees and -1.00 -1.75 x 100 degrees, respectively. Preoperative corneal thickness was 447 microm in the right eye and 446 microm in the left eye. RESULTS: Postoperative corneal thickness decreased to 341 microm and 384 microm in the right and left eye, respectively. Uncorrected visual acuity in the left eye was 20/20, but the right eye developed keratectasia, which led to severe visual loss (20/400). CONCLUSIONS: Photorefractive keratectomy may be better than LASIK for ablative refractive surgery for low myopic astigmatism in eyes with low central corneal thickness.     

Laser in situ keratomileusis for residual hyperopic astigmatism after conductive keratoplasty

PURPOSE: To report a case of laser in situ keratomileusis (LASIK) in a patient with previous conductive keratoplasty. METHODS: A 48-year-old man underwent conductive keratoplasty for low hyperopic astigmatism (manifest refraction OD: +2.25 -0.50 x 77 degrees; OS: +2.50 -0.50 x 105 degrees). Three months postoperatively, UCVA was 20/25 and BSCVA was 20/20 in both eyes; manifest refraction OD: -0.25 -0.75 x 110 degrees; OS: +0.75 -0.75 x 50 degrees. Sixteen months after the operation, regression of refractive outcome was (manifest) OD: +1.75 -1.25 x 90 degrees; OS: +2.50 -0.50 x 85 degrees; UCVA was 20/40 in the right eye and 20/63 in the left eye and BSCVA was 20/20 in both eyes. LASIK was performed for hyperopic regression in the left eye using an automated microkeratome (Alcon SKBM, 130-microm plate; Aesculap-Meditec MEL 70 excimer laser). RESULTS: LASIK was uneventful and no intraoperative or postoperative complications related to the previous conductive keratoplasty procedure or LASIK were observed. Three months after LASIK and 19 months after the initial conductive keratoplasty, the patient's left eye was emmetropic; UCVA was 20/20(-2), BSCVA was 20/20 and manifest refraction was +0.25 -0.25 x 35 degrees. There was a uniform increase in topographical steepening. Visual acuity, refraction and topographic findings remained unchanged at 6 months. CONCLUSIONS: Even though our experience is limited, treatment of hyperopia with LASIK in an eye with refractive regression following previous conductive keratoplasty resulted in a predicted refractive outcome, with no complications, and improvement in visual acuity at 6 months follow-up.     

Reversibility of corneal pigmented arc associated with orthokeratology.

Corneal pigmented (brown) arcs were observed in two orthokeratology patients, both aged 23 years. The preorthokeratology refractive data were OD -5.25 -0.50 x 175 and OS -6.00 -0.75 x 5 for patient A and OD -3.75 -1.00 x 10 and OS -3.00 -1.25 x 175 for patient B. The time course for the development of the arcs was different not only between the two patients but also between the two eyes of patient A. For patient A, the pigmented arc was observed in the left eye 1 week after commencement of lens wear and was not observed in his right eye until a visit about 6 weeks later. For patient B, the arcs were only observed at an aftercare visit about 28 weeks after commencing lens wear. Both patients had been participating in an orthokeratology research study for about 12 months and decided to stop the treatment after completion of the study. The pigmented arcs were no longer present when they returned about 2 months later for assessment of the regression of the refractive and corneal changes induced by the procedure.     

Use of Verisyse/Artisan phakic intraocular lens for the reduction of myopia in a patient with pellucid marginal degeneration

PURPOSE: To describe a patient who underwent implantation of a Verisyse/Artisan iris-fixated phakic intraocular lens (IOL) for correction of high myopia in pellucid marginal degeneration (PMD). METHODS: A patient with PMD was observed during a period of 7 years after the implantation of a Verisyse/Artisan phakic IOL. At each visit, slit-lamp evaluation was performed, and corneal topography, endothelial cell count, manifest refraction, and uncorrected and best-corrected visual acuity were determined. RESULTS: Verisyse/Artisan phakic IOL implantation was performed for the correction of the patient's high myopia in the presence of early-stage PMD. The preoperative refraction of the right eye was -13.0 -3.0 x 90 degrees. The postoperative spherical equivalent (SE) was +0.50 D after 1 year and +0.50 D after 7 years. The preoperative refraction of the left eye was -13.0 -1.25 x 55 degrees. The postoperative SE was -0.38 D after 1 year and -0.13 D after 7 years. Preoperative topographic astigmatism for the right and left eye was 2.94 and 0.81 D, respectively. Seven years later, topographic astigmatism for the right and left eye had changed to 4.45 and 0.71 D, respectively. CONCLUSIONS: This case shows that the implantation of a Verisyse/Artisan phakic IOL may be effective in the treatment of refractive error in PMD. This case discusses the value of a removable (as opposed to a permanent) solution, such as the Verisyse/Artisan phakic IOL device, in the treatment of refractive error in PMD.     

Corneal ectasia after photorefractive keratectomy

Two patients developed corneal ectasia after photorefractive keratectomy (PRK). Case 1 had evidence of early keratoconus preoperatively, with manifest refractions of -4.00 +2.50 x 160 (20/20) in the right eye and -7.00 +3.00 x 180 (20/30) in the left eye; thin corneas (472 microm and 441 microm, respectively); and inferior paracentral steepening in the right eye and central steepening in the left eye on topography. Case 2 had manifest refractions of -8.50 +3.75 x 123 (20/20(-2)) in the right eye and -9.25 +4.00 x 077 (20/20(-1)) in the left eye; corneal thickness of 509 microm and 508 microm, respectively; and symmetric bow-tie patterns in both eyes on topography. Case 2 had a family history suspicious for keratoconus, with a sibling who had bilateral corneal transplantation at a young age. Both patients developed bilateral corneal ectasia after PRK.     

Ferrara intracorneal ring implantation and cataract surgery for the correction of pellucid marginal corneal degeneration

We report a case of Ferrara intracorneal ring (Mediphacos) implantation and cataract surgery for the correction of pellucid marginal corneal degeneration. Preoperatively, the patient's uncorrected visual acuity (UCVA) was 0.05 in the right eye and 0.10 in the left eye. The best spectacle-corrected visual acuity (BSCVA) was 0.50 with -2.00 -11.25 x 80 in the right eye and 0.60 with -2.00 -5.50 x 95 in the left eye. One month postoperatively, the UCVA was 0.50 in the right eye and 0.30 in the left eye. The BSCVA was 0.80 with -1.00 in the right eye and 0.60 with -0.75 -1.25 x 160 in the left eye. Ferrara intrastromal rings and cataract surgery resulted in a more regular corneal shape with a reduction in astigmatism for good visual recovery.     

Detection of an abnormally thick LASIK flap with anterior segment OCT imaging prior to planned LASIK retreatment surgery

PURPOSE: To report a case of an abnormally thick flap that was detected with the use of anterior segment optical coherence tomography (OCT) prior to planned LASIK retreatment surgery. METHODS: A 43-year-old man presented 6 years after bilateral LASIK surgery with uncorrected visual acuity (UCVA) of 20/20 in the right eye and 20/100 in the left eye, and best spectacle-corrected visual acuity (BSCVA) of 20/20 in the right eye and 20/20 in the left eye (refraction -2.25 -1.25 x 131). Anterior segment OCT was performed before LASIK retreatment surgery in the left eye. RESULTS: The flap was found to be 394 microm and the residual stromal bed was too thin (152 microm) to allow for safe LASIK retreatment surgery. After waiting 4 months to ensure refractive stability, photorefractive keratectomy was performed. Postoperative UCVA was 20/20 plano. CONCLUSIONS: The use of anterior segment OCT in the preoperative examination for planned LASIK retreatment surgery provided more reliable data.     

Probability model of the inaccuracy of residual stromal thickness prediction to reduce the risk of ectasia after LASIK part I: quantifying individual risk

PURPOSE: To measure the imprecision of microkeratome cuts, preoperative corneal pachymetry, and laser ablation depth and develop a statistical model to describe the probability of the residual stromal bed thickness (RST) after myopic LASIK being significantly thinner than predicted. METHODS: Preoperative corneal thickness, flap thickness, ablation depth, and RST were measured in 36 eyes by a prototype three-dimensional very high-frequency (VHF) 50 MHz digital ultrasound scanning device (<1.2 microm precision), precursor to the commercially available Artemis 2. All eyes had undergone LASIK with the Moria LSK-One microkeratome and the NIDEK EC-5000 excimer laser. Based on the statistically combined uncertainty (standard deviation) and bias (accuracy to intended value) of corneal thickness measurement, flap thickness, and ablation depth, a continuous probability function was devised describing the chance of obtaining an actual RST less than a specified "cut-off". The model was applied using the data collected from the cohort of eyes. The model was also applied using published flap thickness statistics on a series of microkeratomes. RESULTS: Precision (standard deviation) was 0.74 microm for VHF digital ultrasound measurement of pachymetry, 30.3 microm for Moria LSK-One flap thickness, and 11.2 microm for NIDEK EC-5000 ablation depth. Assuming negligible laser ablation depth bias, the model found the probability that the actual RST will be <200 pmicromgiven a target RST of 250 microm is 7.56% with the Moria LSK-One. The model applied to published flap statistics revealed a range of probabilities of leaving <200 microm given a target RST of 250 microm from <0.01% to 33.6%. CONCLUSIONS: The choice of microkeratome, laser, and pachymeter has a significant impact on the variation of the depth of keratectomy and thus on the risk of ectasia. This model together with high-precision microkeratomes, preoperative pachymetry, and knowledge of laser ablation precision would enable surgeons to determine the specific imprecision of RST prediction for individual LASIK cases and minimize the risk of ectasia.     

Hyperopic LASIK following intracorneal hydrogel lens explantation

PURPOSE: To report hyperopic LASIK results after intracorneal hydrogel lens explantation in a bilateral hyperopic patient. METHODS: Slit-lamp examination showed diffuse corneal opacity around the lens edge and over the anterior lens surface affecting both eyes with uncorrected visual acuity of 0.4 in the right eye and 0.5 in the left eye. RESULTS: The intracorneal hydrogel lenses were explanted, and 6 months later hyperopic LASIK using the Schwind ESIRIS excimer laser (Schwind, Kleinostheim, Germany) was performed after lifting the same flap for the intracorneal hydrogel lens implantation. Six months after hyperopic LASIK, visual acuity recovered to the initial preoperative best spectacle-corrected levels: right eye 0.8 with +1.50 D sphere and left eye 0.9 with +1.00 -0.50 x 90 degrees. Central corneal transparency also fully recovered. CONCLUSIONS: Hyperopic LASIK is a possible alternative after intracorneal hydrogel lens explantation in hyperopic eyes.     

Custom-designed toric phakic intraocular lenses to correct high corneal astigmatism

PURPOSE: To analyze the results of a custom-designed posterior chamber toric phakic intraocular lens (PIOL). METHODS: A 40-year-old woman with high astigmatism and thin corneas underwent bilateral PIOL implantation with the toric Implantable Collamer Lens (ICL) custom-designed and manufactured by STAAR Surgical. The appropriate toric ICL power was calculated to be -8.00 +8.00 x 96 degrees for the right eye and -8.50 +7.50 x 86 degrees for the left eye. Optical zone was 5.5 mm and 6.875 mm at the corneal plane. RESULTS: At 3 and 6 months postoperatively, uncorrected visual acuity (UCVA) and best-spectacle corrected visual acuity (BSCVA) of both eyes had improved to 20/20 and 20/16, respectively. At 19 months, UCVA was 20/20 and 20/16 in the right and left eyes, respectively, and BSCVA had improved to 20/16 and 20/10, respectively. The subjective refraction was stable, with a change of -0.37 +/- 0.17 D from preoperative to 19 months postoperatively. Throughout the postoperative period, iridotomies remained patent and the corneas were clear. CONCLUSIONS: Bilateral implantation of the custom-designed toric ICL successfully corrected the patient's high astigmatism. Preoperative subjective refractive cylinder of -5.25 x 6 degrees in the right eye and -5 x 176 degrees in the left eye changed to -0.5 x 77 degrees and -0.5 x 115 degrees, respectively, after toric IOL implantation. There was almost no change in corneal astigmatism. This customized approach led to UCVA of 20/20 in the right eye and 20/16 in the left eye, and BSCVA of 20/16 in the right eye and 20/10 in the left eye. This is the first report of a toric PIOL being specifically manufactured to meet the refractive cylinder requirements of a specific patient.     

Clinical manifestation and pathologic finding of unilateral acute hydrops after bilateral laser in situ keratomileusis

We present a case of unilateral acute hydrops that developed in 25-year-old man 6 years after bilateral laser in situ keratomileusis (LASIK) for the correction of 2.75 diopters (D) of myopia. Preoperative corneal thickness using ultrasound pachymetry were 556 microm in the right eye and 554 microm in the left eye. Preoperative corneal topography of both eyes showed an asymmetric bow-tie pattern with inferior steepening. Forty-seven months after LASIK, the left eye developed astigmatism and enhancement excimer ablation was performed. Sixteen months after enhancement, a definite sign of keratectasia was detected in the left eye. Twenty-six months after enhancement, acute hydrops occurred in the left eye. The interface of the LASIK wound was separated and filled with aqueous humor. Penetrating keratoplasty was performed to avoid perforation. The keratocytes at the edge between the peripheral flap and remaining stroma showed mixoid degeneration and edematous change suggesting dying cells.     

Refractive lensectomy and cross-cylinder laser in situ keratomileusis for the correction of extreme hyperopic astigmatism

Refractive lensectomy followed by cross-cylinder laser in situ keratomileusis was performed in both eyes of a 46-year-old patient with extreme hyperopic astigmatism. Six months postoperatively, the uncorrected visual acuity was 20/25 with a manifest refraction of +0.25 -0.50 x 44 in the right eye and +0.25 -0.25 x 10 in the left eye. The best corrected visual acuity remained unchanged in both eyes at 20/25. Refractive lensectomy and cross-cylinder LASIK can be effective for treating extreme hyperopic astigmatism.     

Reversal of myopic anisometropic amblyopia with phakic intraocular lens implantation

PURPOSE: To report a case of reversal of myopic anisometropic amblyopia with phakic intraocular lens implantation. METHODS: A 6-year-old boy with anisometropic amblyopia with spherical equivalent refraction of right eye: -14.00 -3.00 x 100 degrees, left eye: -0.50 -3.25 x 90 degrees, was treated for 2 years with occlusion to the left eye, with poor results. Refractive surgery was planned because of contact lens intolerance at age 8 years. A -15.00-D iris claw Artisan intraocular lens (IOL) was implanted. RESULTS: Following surgery, treatment of the amblyopia and spectacle correction of -4.00 D cylinder at 85 degrees in the right eye and -3.50 D cylinder at 90 degrees in the left eye was necessary. Visual acuity 6 months after surgery was 20/25 in the right eye and 20/20 in the left eye, and has remained stable 18 months after surgery. CONCLUSION: Myopic anisometropic amblyopia in an 8-year-old boy was treated successfully with implantation of an Artisan iris claw phakic anterior chamber IOL, combined with occlusion therapy, and resulted in reversal of amblyopia.