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Purpose: To evaluate the efficacy of conductive keratoplasty in the treatment of pre-existing and surgically induced hyperopic astigmatism., Methods: In this prospective, noncomparative case series, four eyes of four subjects, two female and two male (age 25 to 47 yr) were treated for hyperopia (up to +5.50 D) and hyperopic astigmatism (up to +5.75 D) with the Refractec ViewPoint conductive keratoplasty system. The follow-up period was 6 months. Uncorrected and spectacle-corrected visual acuity, manifest and cycloplegic refraction, and videokeratographs were obtained before and after surgery. We treated two patients who had already had LASIK, one of them with a decentered ablation and the other with flap striae, one patient after PRK, and one patient with keratoconus., Results: No complications were observed. No eye lost lines of spectacle-corrected visual acuity. All eyes showed improvement of uncorrected visual acuity of 3 or more lines. Videokeratographs demonstrated improved centration and reduction in keratometric power readings. Each eye was analyzed separately, including a comparative analysis of the proposed nomograms and quality of vision after surgery., Conclusions: Conductive keratoplasty may be a minimally invasive solution for patients with irregular hyperopic astigmatism, offering improved quality of vision in instances of flap striae by tightening the central cornea.

Objective: To prospectively study the effects of the use of Intacs microthin prescription inserts (Addition Technology Inc, Fremont, Calif) for the postoperative management of corneal ectasia resulting from laser in situ keratomileusis (LASIK)., Methods: In this prospective nonrandomized clinical trial, 10 eyes of 7 patients with post-LASIK corneal ectasia (2 men and 5 women) aged 33 to 46 years (mean +/- SD, 40.67 +/- 5.99 years) were included. The follow-up ranged from 6 to 24 months (mean +/- SD, 15.0 +/- 6.5 months). Two Intacs segments of thickness depending on the residual refraction of the patients were inserted in each eye., Main Outcome Measures: Uncorrected visual acuity, best spectacle-corrected visual acuity, refractive outcome, and topographic findings after Intacs implantation., Results: Intacs were successfully implanted in all eyes. Spherical equivalent error was statistically significantly reduced after Intacs implantation (pre-Intacs, mean +/- SD: -4.81 +/- 3.24 Diopters (D) (range, -13.75 to -2.50 D) to -0.96 +/- 2.93 D (range, -8.75 to 2.50 D) (P<.001). Pre-Intacs uncorrected visual acuity was 20/100 or worse in all eyes (range, counting fingers to 20/100) while at the last follow-up examination, 9 (90%) of 10 eyes had uncorrected visual acuity of 20/40 or better (range, counting fingers to 20/20). Three eyes maintained the pre-Intacs best spectacle-corrected visual acuity while the rest of the eyes (7) experienced a gain of 1 to 2 lines. The mean difference between pre-Intacs and last follow-up best spectacle-corrected visual acuity was a gain of 1.00 +/- 0.82 lines., Conclusions: Intracorneal ring segments implantation improved uncorrected visual acuity and best spectacle-corrected visual acuity in patients with post-LASIK ectasia. Even though the results are encouraging, concern still exists regarding the long-term effect of such an approach for the management of post-LASIK ectasia.

Background: To compare the corneal healing response between conventional and phototherapeutic keratectomy through a masking agent, in rabbit corneas., Methods: 24 adult rabbits underwent phototherapeutic keratectomy. Animals were divided in two groups: 12 received photoablation through a masking agent (PALM gel) and the remaining 12 received conventional phototherapeutic keratectomy of equal depth and served as control. Light and transmission electron microscopy was performed in specimens of both groups obtained: immediately after, four hours, one week, one, three and six months after treatment., Results: Reepitheliazation was complete within five days in all eyes. Light and transmission electron microscopy did not reveal any differences of the healing process in the experimental eyes compared to the controls., Conclusion: Photoablation through the PALM technique did not result any evident alterations of the reepithelisation and stromal healing process.

Purpose: To prospectively study the effects of the use of Intacs microthin prescription inserts for the management of keratoconus., Design: Prospective nonrandomized clinical trial., Methods: Thirty-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., Results: Intacs 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., Conclusions: With 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.

To prospectively compare the influence of fornix-based and limbus-based conjunctival flaps on the final outcome and complications of 2-site phacotrabeculectomy with mitomycin-C in fellow eyes of patients with bilateral open-angle glaucoma (OAG). Glaucoma Unit, Department of Ophthalmology, University of Crete, Crete, Greece.Twenty-two patients with bilateral primary OAG and 8 patients with bilateral exfoliative glaucoma had 2-site phacotrabeculectomy in both eyes. Eyes were randomly assigned to the fornix-based flap or limbus-based flap group by the use of random tables. The intraocular pressure (IOP) decreased significantly in both groups (P <.01); however, there was no statistically significant difference between the groups in the amount of IOP decrease or the number of postoperative antiglaucoma medications after a 1-year follow-up. Faster improvement in visual acuity was observed in the fornix-based group during the first week. The mean time of surgery was 3.5 minutes less in the fornix-based group. An increased incidence of fibrin exudation, pupillary membrane formation, and capsule opacification was found in eyes with exfoliative glaucoma. The early bleb leakage was 3 times more frequent in the fornix-based group. The type of conjunctival flap in a 2-site phacotrabeculectomy did not seem to influence the final outcome. The main advantage of the fornix-based conjunctival flap is the shorter surgical time and the relatively faster improvement in vision postoperatively. The main disadvantage is more frequent early bleb leakage.

Purpose: To determine how refractive error, visual acuity, and high-order aberrations (3rd- and 4th-order) are affected by the formation of a lamellar corneal flap during laser in situ keratomileusis (LASIK)., Setting: University refractive surgery center., Methods: The effect of lamellar corneal flap formation was analyzed in 15 myopic eyes (mean preoperative refraction -4.72 diopters [D] [range -1.25 to -7.25 D]). The flap was created using a 2-step procedure: (1). a nasally hinged lamellar corneal flap was created; (2). the flap was lifted and stromal ablation performed 2 months after the flap was made. A Hartmann-Shack aberrometer was used to measure the aberrations., Results: There was no significant change in the refractive error (spherical equivalent pre-flap -4.72 +/- 1.99 D and post-flap -4.62 +/- 1.99 D [P =.28]) or visual acuity (pre-flap uncorrected visual acuity [UCVA] 0.07 and best corrected visual acuity [BCVA] 0.96; post-flap UCVA 0.08 and BCVA 0.95 [P =.16 and P =.33, respectively]). A statistically significant increase in total higher-order wavefront aberrations was observed following flap formation (root mean square pre-flap 0.344 +/- 0.125 and post-flap 0.440 +/- 0.221 [P =.04])., Conclusion: Flap formation during LASIK can modify the eye's existing natural higher-order aberrations (especially spherical and coma-like aberrations along the axis of the flap's hinge), while visual acuity and refractive error remain unaffected.

Purpose: To prospectively study and compare the effectiveness and the safety of primary deep sclerectomy with and without the use of mitomycin C in eyes with open-angle glaucoma., Patients and Methods: A total of 90 eyes of 90 patients with primary open-angle glaucoma or pseudoexfoliative glaucoma underwent deep sclerectomy. Patients were enrolled consecutively and assigned randomly to undergo deep sclerectomy without the use of mitomycin C (DS group) and deep sclerectomy with the application of mitomycin C (DSMMC group) in a concentration of 0.2 mg/mL for 2.5 minutes, before the superficial scleral flap formation., Results: The intraocular pressure was significantly decreased by 7.13 mm Hg or 27.59% in the DS group and by 11.68 mm Hg or 42.25% in the DSMMC group at the end of the follow-up period. The intraocular pressure reduction in the DSMMC group was statistically significant when compared with that in the DS group (P <0.05). The complete (IOP <22 mm Hg without medication) and qualified (IOP < 22 mm Hg with or without medication) success rates at the end of the follow-up period were 42.5% and 72.5% in the DS group and 50% and 95% in the DSMMC group. The qualified success rate in the DSMMC group was statistically significant when compared with that in the DS group. Differences in complications (choroidal detachment, hyphema, leakage) seen between the two groups were statistically nonsignificant. A hemorrhagic detachment of the Descemet membrane was observed in one eye in the DSMMC group., Conclusions: The use of intraoperative mitomycin C during deep sclerectomy significantly reduced the postoperative IOP and increased the success rate of the procedure.

Purpose: To evaluate the effect of an intraocular gas bubble on ocular wall pulsation., Methods: Eight patients that underwent vitrectomy with intraocular gas injection for various reasons were studied. Ocular pulsation was evaluated in a semi-quantitative way by means of Goldman applanation tonometry in both eyes before and after the operation. Vitreous cavity gas fill in the operated eye was estimated by means of indirect ophthalmoscopy and was correlated with ocular pulsation. The follow up lasted until the gas totally disappeared., Results: Ocular pulsation disappeared postoperatively in the operated eye and gradually reappeared when the gas fill diminished. Pulsation returned to preoperative level when the gas disappeared from the vitreous cavity. A negative statistical correlation between ocular pulsation and gas fill could be documented., Conclusion: The compressible nature of the intraocular gas bubble results in absorption of the vascular pulsation and prevents its transfer to the ocular wall. This leads to attenuation or even cancellation of ocular wall pulsation when a gas bubble exists within the eye.

Purpose: To test the accuracy and reliability of the first-generation prototype of Tracey-1, a ray-tracing refractometer., Setting: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA., Methods: The refractive spherical equivalent (SE) and astigmatism measured by Tracey-1, subjective manifest refraction (MR), and autorefraction (AR) (Nidek AR-3300) were compared in 58 pseudophakic eyes of 44 patients with a mean age of 69.95 years +/- 8.6 (SD). The astigmatic values obtained from Tracey-1 and computerized videokeratography were also compared. Astigmatism values were compared using power vector analysis., Results: The mean SEs measured by MR, Tracey, and AR were -0.76 diopter (D) +/- 0.96 (SD) (range 1.00 to -3.00 D), 0.37 +/- 0.64 D (range 1.68 to -1.49 D), and -0.44 +/- 1.13 D (range 1.63 to -3.50 D), respectively. The Pearson correlation coefficients between MR and Tracey values and between MR and AR values were high (r = 0.895 and r = 0.875, respectively; both P < .0001). However, the mean difference between the Tracey and MR values was 1.13 +/- 0.48 D (range 2.45 to -0.06 D) (P < .001). The mean cylindrical differences between MR and Tracey and between MR and AR were 0.03 +/- 0.51 D (range 1.22 to -1.07 D) (P = .709) and -0.30 +/- 0.62 D (range 0.50 to -2.25 D) (P = .003), respectively. Power vector analysis revealed difference vectors of -0.16 x 60 between Tracey and MR and -0.22 x 87 between AR and MR., Conclusions: Spherical and cylindrical refractive data obtained with the Tracey system correlated well with those derived from MR; however, there was a mean spherical error of approximately 1.10 D. Further work is required to refine the accuracy and range of this device.

Objective: To identify the incidence and refractive outcome of intraoperative laser in situ keratomileusis (LASIK) complications using one type of microkeratome., Design: Retrospective noncomparative case series., Participants: Three hundred thirty-four consecutive myopic LASIK patients (September 1997 to November 1998) operated on by one surgeon., Intervention: Myopic LASIK surgeries were performed with the Mediate Mel 60 Aesculap Meditec Laser system., Main Outcome Measures: Preoperative and 1-year postoperative spherical equivalent, best spectacle-corrected visual acuity (BSVA), and corneal anatomic features (as obtained from videokeratography) were recorded, as was the incidence of intraoperative complications., Results: Forty-eight (14%) eyes had keratome-related complications. Thirty-seven (77%) eyes were immediately treated; the remaining eyes were treated on a later date. One year after treatment, 13% of the immediately treated complicated eyes maintained the preoperative BSVA; 24% had a 1-line loss; 2.7% had a greater loss of BSVA., Conclusions: Microkeratome-related complications may result in loss of BSVA. The complication of an irregular flap had the poorest refractive outcome in this series of eyes. We did not find any statistically significant relationship between corneal anatomic factors and keratome-related complications in this series.

Purpose: To evaluate the safety and efficacy of intrastromal corneal ring segments (ICRS, INTACS, Keravision) for the correction of corneal ectasia after laser in situ keratomileusis (LASIK)., Methods: In this prospective, noncomparative case series, INTACS were implanted in three eyes (two patients) that were ectatic after LASIK. Mean follow-up was 8.7 months (range, 8 to 10 mo)., Results: No intraoperative complications occurred. After INTACS implantation, uncorrected visual acuity ranged from 20/20 to 20/25 at 6 months and remained stable until 9 months. Mean postoperative spherical equivalent refraction was 0.50 D at 1 month and no significant changes appeared up to 9 months after INTACS implantation. After INTACS implantation, no eye lost any lines of Snellen spectacle-corrected visual acuity and two eyes gained from one to two lines. There was an increase in topographical regularity in all three eyes., Conclusion: Implantation of INTACS in eyes with corneal ectasia after LASIK resulted in good refractive outcome, absence of complications, and improvement in visual acuity.