Lines Of Uncorrected Visual Acuity Research Articles

Accelerated versus conventional corneal collagen crosslinking: Short-term clinical outcomes in stabilizing keratoconus.

PURPOSE:The purpose of the study is to compare the short-term outcomes of corneal collagen crosslinking (CXL) using the conventional (Dresden) protocol and an accelerated CXL (ACXL) protocol to stop keratoconus (KC) progression.METHODS:A chart review was performed for all the patients with KC who underwent CXL in the last 7 years. Data were compared at baseline and at all follow-up examinations for uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BCVA), keratometry (K), central corneal thickness, and complications of CXL. Pre- and post-intervention values were compared for each group. P < 0.05 was statistically significant.RESULTS:After the treatment, there was a statistically greater improvement in UCVA in the conventional CXL (CCXL) group (49%) compared to the ACXL group (34%) (P = 0.028). The improvement in BCVA was similar between the groups (P = 0.060). Gain of two lines of UCVA and stability were comparable between groups (P = 0.078 and P = 0.060, respectively). The average flat K and steep K values fluctuated remarkably across different follow-up assessments in both the groups. At 3 months of follow-up, there was a statistically significantly faster return to baseline levels of flat and steep Ks in the CCXL group (P = 0.028 and P = 0.002, respectively).CONCLUSION:The findings of the current study confirm the efficacy and safety of accelerated high-fluence CXL compared to CCXL. Both protocols were effective in stabilizing KC at 9th-month and the last follow-up visit. Larger prospective randomized controlled trials and longer follow-up are required to confirm our findings.

Black diaphragm intraocular lens implantation in patients with aniridia

Purpose:To review the management outcomes of black diaphragm intraocular (BDI) lens implantation in Arab patients with aniridia.Methods:Patients with aniridia undergone BDI lens implantation at our institution between 2013 and 2014 were included. Uncorrected visual acuity (UCVA), manifest refraction, and best-corrected visual acuity (BCVA) were evaluated before and 6 months and yearly after BDI lens implant surgery until the last visit. Intra- and postoperative complications were noted.Results:Our series comprised 14 patients (8 males) with aniridia. The median duration of follow-up was 30 months (25% quartile). Ocular parameters, refractive status, and vison were all significantly improved at the last follow-up compared to the preoperative values (P < 0.05 for all comparisons). All patients reported a significant decrease in photophobia and glare. Postoperatively, 11 eyes (78%) gained 2 or more lines of UCVA. At the last follow-up, BCVA increased by 2 or more lines in all cases. Early postoperative complications included main wound leakage (one eye) and anterior chamber hyphema (one eye). Late (≥6 months) complications included corneal decompensation (one eye), failed penetrating keratoplasty graft (2 eyes), and subluxation of a scleral fixated BDI lens (one eye). Surgical interventions performed to manage complications included penetrating keratoplasty in 2 eyes with corneal decompensation and failed graft (one each), and re-suturing of a subluxated intraocular lens (one eye).Conclusion:BDI lenses seem to be a safe and effective iris prosthetic with intraocular lens combination surgery for patients with congenital or traumatic aniridia. Periodic evaluation and prompt management of complications are recommended.

Customized photorefractive keratectomy to correct high ametropia after penetrating keratoplasty: A pilot study

PurposeTo evaluate preliminarily the safety and efficacy of customized photorefractive keratectomy (PRK) to correct ametropia and irregular astigmatism after penetrating keratoplasty (PK). MethodsThis pilot study included five eyes of five patients with a mean spherical equivalent of −5.1±1.46D (range from −2.75 to −6.50D). In all cases, ametropia and irregular astigmatism was corrected with topography-guided customized PRK. Ocular examinations with topographic analysis were performed preoperatively as well as at 1, 3 and 6 months after surgery. ResultsAll eyes gained postoperatively at least three Snellen lines of uncorrected visual acuity. Mean refractive spherical equivalent was 0.62±0.63D (range from −0.25 to −1.75D) at 6 months postoperatively. ConclusionOur pilot study suggests that customized PRK can be a safe and effective method for treating ametropia and irregular astigmatisms after PK. Future studies with larger samples and longer follow-ups should be performed to confirm these results.

Refractive Surgery in Children: Is it Ready for Prime Time?

IntroductionPotential indications for excimer laser procedures in children include accommodative esotropia, bilateral high ametropia, and severe anisometropia. Treatment of these conditions has traditionally included spectacle or contact lens use. This treatment, however, is often ineffective in children with severe anisometropia or bilateral ametropia, especially those with neuropsychological disorders. Refractive surgery may be a viable treatment option for these conditions.MethodsThe visual and refractive results from our studies on photorefractive keratectomy for pediatric anisometropic amblyopia are discussed. Also, I will present a review of the world literature on excimer laser procedures for accommodative esotropia, pediatric high anisometropia, and pediatric bilateral high ametropia.ResultsIn our study, at 36 months follow-up, 7 of 9 patients who were able to perform psychophysical acuity testing preoperatively had improvement of two or more lines of uncorrected visual acuity and 6 of 9 had improvement of two or more lines of best corrected visual acuity. Fifty percent of the myopic patients and 100% of the hyperopic patients were within 2 D of refractive target at the 36-month follow-up visit. Refractive error stability has been good and corneal haze has been minimal.ConclusionsRefractive surgery in children to reduce amblyopiogenic levels of refractive error is proving to be relatively stable. Best corrected and uncorrected visual acuity has also been shown to improve following the excimer laser procedures. Refractive surgery also appears to be effective for pure accommodative esotropia. Randomized clinical trials are needed to fully establish safety and efficacy. Other refractive procedures, such as clear lens extraction and phakic intraocular lenses, may also prove to be valid treatment options for these conditions in the future.

Customized transepithelial photorefractive keratectomy for iatrogenic ametropia after penetrating or deep lamellar keratoplasty

To evaluate the safety and efficacy of customized transepithelial photorefractive keratectomy (PRK) for the correction of iatrogenic ametropia after penetrating keratoplasty (PKP) or deep lamellar keratoplasty. Eye Clinic, Department of Neurological and Visual Sciences, University of Verona, Verona, Italy. This study comprised 9 patients who had irregular astigmatism from 2.0 to 8.0 diopters (D) after PKP or deep lamellar keratoplasty. The ametropia was corrected with customized transepithelial PRK and the Corneal Interactive Programmed Topographic Ablation (CIPTA) software program (LIGI). Complete ophthalmic examinations were performed before and after surgery. The mean age of the patients was 39.2 years (range 31 to 59 years). All patients gained at least 2 Snellen lines of uncorrected visual acuity; 2 patients had an increase of at least 5 lines, and 3 patients had an increase of 8 lines. The mean refractive spherical equivalent changed from -2.98 D +/- 3.11 (SD) (range -7.25 to +3.00 D) before PRK to -0.58 +/- 0.84 D (range 0 to -2.50 D) at the last follow-up visit. One patient presented with grade 1 haze that did not improve with topical steroid therapy. No patient lost best spectacle-corrected visual acuity. Customized transepithelial PRK with the CIPTA software was a safe and effective treatment for irregular astigmatism after PKP or deep lamellar keratoplasty.

Management of keratoconus with Intacs

PurposeTo prospectively study the effects of the use of Intacs microthin prescription inserts for the management of keratoconus. DesignProspective nonrandomized clinical trial. MethodsThirty-three eyes of 26 keratoconus patients (17 males and 9 females) ages 21 to 51 years (mean age, 32 ± 9.7 years) were included in the current study. All patients had clear central corneas and contact lens intolerance. Patients were excluded if any of the following criteria applied after the preoperative examination: previous intraocular or corneal surgery; history of herpes keratitis; diagnosed autoimmune disease; and systemic connective tissue disease. Two Intacs segments of 0.45-mm thickness were inserted in the cornea of each eye, aiming at embracing the keratoconus area to try to achieve maximal flattening. Preoperative examination included uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest refraction, keratometric data, and corneal topography. ResultsIntacs were successfully implanted in all eyes. In one eye Intacs were removed after 3 months because of their improper (superficial) placement. The follow-up ranged from 1 to 24 months (mean: 11.3 months). The mean UCVA significantly improved from 0.13 ± 0.14 (range, counting fingers [CF]–0.5) to 0.39 ± 0.27 (range, CF-1.0) (P < .01). Of 33 eyes, 2 eyes lost 1 line of UCVA, and 3 eyes maintained the preoperative UCVA, whereas the rest (28 eyes) experienced a 1- to 10-line gain. The mean BCVA also improved from 0.47 ± 0.31 (range, CF-1.0) to 0.64 ± 0.26 (range, 0.1-1.0) (P < .01). Of 33 eyes, 4 eyes experienced 1- to 2-line loss of BCVA, 4 eyes maintained the preoperative BCVA, whereas the rest (25 eyes), experienced a 1- to 6-line gain. Of 3 patients (3 eyes) with unsatisfactory results, 1 patient improved with one segment removal and in 2 patients the segments were permanently removed. One of these eyes underwent successful PKP. ConclusionsWith mean follow-up of 11.3 months, intracorneal ring segments implantation improved UCVA and BCVA in the majority of the keratoconus patients. Even though the results are encouraging, concern still exists regarding the predictability as well as the long-term effect of such an approach for the management of keratoconus.

Laser in situ Keratomileusis for Anisometropic Amblyopia

To evaluate the efficacy and benefit of laser in situ keratomileusis (LASIK) for correction of anisometropic amblyopia. LASER was performed in 21 eyes of 21 anisometropic amblyopes with a mean age of 27.71 ± 12.24 years. Three patients were less than 18 years of age. LASIK was performed in the more myopic and amblyopic eye using the Chiron Automated Corneal Shaper microkeratome and the Nidek EC-5000 excimer laser system. Results of 3-month follow-up are presented. Preoperative mean manifest spherical equivalent refraction was -13.20 ± 3.84 D (range, -5.25 to -20.00 D). Mean attempted correction was -12.28 ± 3.47 D. Mean postoperative refraction at 3 months was -0.78 ± 1.63 D. Postoperative uncorrected visual acuity improved by 2 or more lines in all patients and was the same or better than preoperative best spectacle-corrected visual acuity in 95.2% of eyes. Best spectacle-corrected visual acuity improved by 1 or more lines in 61.9% of eyes. The 12-year-old child had a gain of more than 4 lines of uncorrected visual acuity. LASIK was a good alternative to contact lenses in adults for anisometropia and resulted in a gain of best spectacle-corrected visual acuity. In children it may be an alternative method of treatment for amblyopia. [J Refract Surg 2000;16(suppl):S264-S267].

Adjustability of refractive effect for corneal ring segments.

To evaluate the safety and efficacy of adjustability of the refractive effect of intrastromal corneal ring segments (ICRS, Intacs). Data from four patients who had their initial Intacs removed and exchanged for new Intacs of different thickness sizes during a United States Food and Drug Adminstration Phase II clinical trial were evaluated with regard to segment size, reasons for exchange, duration within the cornea before exchange procedure, loss or change of spectacle-corrected visual acuity, change of uncorrected visual acuity, manifest refraction, cycloplegic refraction, topography after exchange, and stability of refraction. The exchange procedure was performed in two patients due to undercorrection and in two for overcorrection. The length of time the segments remained in the cornea after initial surgery varied from 6 to 15 months (mean, 10.25 +/- 4.03 mo). The most recent examination occurred between 4 to 18 months (mean, 10.0 +/- 6.32 mo) following the exchange procedure and showed improved uncorrected visual acuity with a range from 20/16 to 20/20 and a gain of 2 to 7 lines of uncorrected visual acuity compared to baseline. No eyes lost any lines of spectacle-corrected visual acuity following the exchange procedure and all preserved their preoperative spectacle-corrected visual acuity of 20/16. The intended refractive correction was achieved in the first few days of the exchange procedure and remained stable. In these four eyes that were over- or undercorrected after initial Intacs placement, segment thickness sizes were exchanged after 6, 8, 12, and 15 months without complication and with final uncorrected visual acuities of 20/16 to 20/20.

Correcting simple myopic astigmatism with the excimer laser

For one year we followed 46 eyes that had photoastigmatic refractive keratectomy with an excimer laser to correct simple myopic astigmatism. Mean preoperative cylinder was −2.50 ± 0.70 diopters (D); mean preoperative best corrected visual acuity was 20/25 ± 1 Snellen line. Mean postoperative refraction one year after surgery was −0.5 ± 0.2, and mean uncorrected visual acuity was 20/25 ± 1 Snellen line. In all eyes, the final axis of the residual cylinder was ±5 degrees around the preoperative axis. Uncorrected visual acuity equaled best preoperative acuity in 24 eyes. Eight eyes gained one line of best corrected visual acuity, six gained more than one line, and eight lost one line. No patient lost more than one line of uncorrected visual acuity. No significant complications such as haze, halos, eccentric ablation, or hypercorrection were observed.