Femtosecond LASIK Retreatments After Primary Myopic Photorefractive Keratectomy.

PURPOSE: The purpose of the study was to evaluate the results and complications of laser-assisted in situ keratomileusis (LASIK) using a femtosecond laser as a retreatment modality of myopia and myopic astigmatism after previous myopic photorefractive keratectomy (PRK). METHODS: In this retrospective, consecutive, noncomparative case series study, 69 eyes of 41 patients receiving femtosecond LASIK after previous myopic PRK were evaluated. The mean age was 43.0 ± 8.9 years. The preoperative mean SE was -1.82 ± 1.01 diopter (D), range -0.62 to -6.25. The mean central epithelial thickness was 65 ± 5 µm. A flap was created using a low-energy femtosecond laser (Ziemer LDV Z8), with a programmed thickness calculated by adding 40 µm to the epithelial thickness. Refractive ablation was performed using a Technolas Teneo 317 laser (Bausch and Lomb). RESULTS: Twelve months after LASIK, the mean SE was -0.03 ± 0.17 D, with all eyes ≤0.50 D of SE. The mean DE was 0.30 ± 0.25, with 62 eyes (89.9%) ≤0.50 D and all eyes ≤1 D. The mean corrected distance visual acuity (CDVA) was 0.04 ± 0.10 logMAR; no eye lost more than 1 line of CDVA. The mean uncorrected distance visual acuity was 0.07 ± 0.13 logMAR, being 20/25 or better in all eyes. The safety index (postoperative CDVA/preoperative CDVA) was 1.05. The efficacy index (postoperative uncorrected distance visual acuity/preoperative CDVA) was 0.98. No significant complications occurred. CONCLUSIONS: Myopic retreatments by femtosecond LASIK after primary PRK yielded excellent refractive results without relevant complications. The flap thickness must be tailored to the epithelial thickening after PRK.

Refractive Corneal Lenticule Extraction With the CLEAR Femtosecond Laser Application.

PURPOSE: The aim of this study was to evaluate a new femtosecond laser application for refractive corneal lenticule extraction with suction control and computerized regulation of centration and alignment (Ziemer CLEAR). METHODS: This was a retrospective, consecutive, noncomparative case series study. Patients undergoing CLEAR for spherical equivalent (SE) between -3 and -10 D, evaluating SE, defocus equivalent, refractive astigmatism, visual acuity, and centration at 10 months were evaluated in the study. RESULTS: Fifty-three eyes of 42 patients (mean age 40.4 ± 8.6 years) were included, with preoperative SE -5.99 ± 1.49 D and mean corrected distance visual acuity (CDVA) of 0.05 ± 0.07 logMAR. With no suction losses, an intact lenticule was extracted in all eyes. In 6 eyes, peripheral adhesion was resolved by lenticulerrhexis, and in 1 eye, the incision was opened by a crescent blade. Moderate interface inflammation occurred in 3 eyes. At day 1, in the 42 eyes with uneventful surgery, the mean CDVA was 20/27, whereas in the 11 eyes with extra surgical manipulations, it was 20/36 ( P = 0.04). At 10 months, for the 53 eyes, the mean uncorrected distance visual acuity was 0.05 ± 0.09 logMAR; in 37 eyes (70%), it was 20/25 or better; and the mean CDVA was 0.04 ± 0.06 logMAR. Eight eyes (15%) lost 1 logMAR line. The mean SE was -0.13 ± 0.15 D. The mean defocus equivalent was 0.33 ± 0.32 D, with 46 eyes (87%) ≤0.50 D and 52 eyes (98%) ≤1 D. Refractive astigmatism was ≤0.50 D in 48 eyes (90%). The efficacy index was 1.00, and the safety index was 0.98. The mean decentration from the corneal vertex was 0.28 ± 0.07 mm. CONCLUSIONS: The application yielded good predictability, efficacy, and safety. Slower visual recovery was observed after extra surgical manipulations.

Change in Stromal Thickness and Anterior Curvature After Refractive Corneal Lenticule Extraction With the CLEAR Application.

PURPOSE: To measure the changes in stromal thickness and anterior corneal curvature after corneal lenticule extraction for the correction of myopia and myopic astigmatism with the Corneal Lenticule Extraction for Advanced Refractive correction (CLEAR) application (Ziemer Group). METHODS: The correlations between achieved correction on maximum myopic meridian and stromal thinning and spherical equivalent of achieved correction and anterior corneal flattening were evaluated by optical coherence tomography 6 months after CLEAR in 78 eyes of 78 patients in a retrospective, consecutive, non-comparative case series study. RESULTS: With an optical zone of 6.5 mm (52 eyes), the mean correction achieved was -5.80 ± 1.52 diopters (D) (range: -2.25 to -9.25 D), the mean stromal thinning was 104 ± 15 µm (range: 76 to 138 µm), and the regression line was: µm of thinning = 8.46 • D of correction + 55.25. With an optical zone of 6 mm (26 eyes), the mean correction achieved was -8.33 ± 1.61 D (range: -5.50 to -11.00 D), the mean stromal thinning was 114 ± 12 µm (range: 93 to 144 µm), and the regression line was: µm of thinning = 6.35 • D of correction + 60.92. With 6.5 mm, the mean corneal flattening was 4.27 ± 0.88 D, and the regression line was: D of flattening = 0.50 • D of correction + 1.60. With 6 mm, the mean corneal flattening was 6.40 ± 0.70 D, and the regression line was: D of flattening = 0.37 • D of correction + 2.36. CONCLUSIONS: Stromal thinning and anterior corneal flattening were correlated with the amount of myopic correction in a linear fashion. The thinning was significantly less than predicted by the laser software. [J Refract Surg. 2022;38(12):797-804.].

Refractive Corneal Lenticule Extraction on Previous Photorefractive Keratectomy, with Optical Coherence Tomography Study.

We report the first case of refractive corneal lenticule extraction with the femtosecond laser application CLEAR as retreatment technique after previous laser vision correction. A 42-year-old woman, operated by bilateral photorefractive keratectomy (PRK) 19 years previously, with moderate dry eye, came for post-PRK regression and underwent correction of a residual myopia of -3 -0.5 × 159° D in the left eye by CLEAR. Surgery was uneventful, with a regular laser pattern and a normal dissection of the lenticule. At day 1, uncorrected visual acuity was 20/25; at 3 months, it was 20/20, with a refraction of +0.25 × 115° D. The cornea and interface were regular and transparent; no dry eye symptoms occurred. At 3 months, on optical coherence tomography, the treatment was well centered, the surgical interface was centrally regular, whereas the anterior profile of the stromal surface was slightly corrugated, compensated by a smooth epithelial surface. The present case demonstrates that myopia after PRK can be achieved by CLEAR; an irregular stromal surface may occur, not affecting the visual result in virtue of epithelial remodeling.

Traumatic Flap Complications After Femtosecond LASIK.

PURPOSE: The purpose of this article was to evaluate the prognosis of traumatic flap dislocation or avulsion in a large series of laser-assisted in situ keratomileusis (LASIK) cases. METHODS: Retrospective, consecutive, noncomparative case series analyzes the visual and anatomical results after flap dislocation or avulsion, caused by trauma occurred at least 1 month after LASIK. RESULTS: A total of 37,315 eyes of 19,602 patients were reviewed. A traumatic flap complication was observed in 9 eyes of 9 patients, with a maximum interval of 37 months after surgery. Flap dislocation with central full-thickness folds was found in 5 cases; flap lifting and repositioning achieved a full recovery of uncorrected visual acuity. In another case, a partially detached flap was repositioned by a microsponge without lifting; self-limiting localized epithelial ingrowth followed. In 3 eyes, a complete flap avulsion occurred and, after epithelialization, a moderate refractive change was observed, comprised between -0.25 and -1 diopters (D) of spherical equivalent, with astigmatism <1 D; in 1 eye, the resulting myopia was corrected by repeat femtosecond LASIK. CONCLUSIONS: Traumatic flap complications after femtosecond LASIK are rare but can occur even in the long term; they have a favorable anatomic and visual prognosis.

Diffuse lamellar keratitis after LASIK with low-energy femtosecond laser.

PURPOSE: To evaluate the incidence, evolution, and prognosis of diffuse lamellar keratitis (DLK) in a large series of laser in situ keratomileusis (LASIK) with low-energy femtosecond laser. SETTING: Private practice, Siena, Italy. DESIGN: Retrospective, consecutive, noncomparative case series study. METHODS: Single-use instruments, powder-free gloves, and no corneal marking were used. Flap was created by a low-energy femtosecond laser (Ziemer Z2 and Z4). RESULTS: A total of 37 315 eyes of 19 602 patients were reviewed. DLK was observed in 236 eyes (0.63%) of 149 patients (0.76%). Grade 1 DLK was observed in 231 eyes of 142 patients, grade 2 in 1 eye: when treated with topical steroids, they had no visual consequences. Three patients had bilateral grade 3 to 4 DLK: one of them, with bilateral grade 3, despite flap lifting and irrigation worsened to stage 4 (central stroma thinning and flattening), partially recovered in 2 years, and underwent repeat femtosecond laser-assisted LASIK for hyperopic shift in 1 eye. In all the 5 eyes that developed grade 4 DLK, corneal thickness decreased until the first month and then partially recovered; mean final tissue loss at 1 to 2 years was 35 µm. Compensatory epithelial thickening was observed. CONCLUSIONS: DLK after low-energy femtosecond laser-assisted LASIK is rare; severe DLK (stages 3 and 4) was found in only 6 eyes (0.016%). Flap lifting and irrigation might not prevent progression. Spontaneous reformation of stromal tissue and epithelial thickening improve visual acuity in the long term; residual hyperopic shift can be corrected by repeat femtosecond laser-assisted LASIK.

Factors influencing pupil behaviour during femtosecond laser assisted cataract surgery.

AIM: Femtosecond laser assisted cataract surgery is associated with pupillary constriction. This study aims to look at patient and surgical factors predisposing to abnormal pupil behaviour during FLACS. METHODS: This prospective observational study included all patients undergoing FLACS in the Princess of Wales Hospital, Bridgend, UK between February and June 2017. Pupils were measured at three time points; immediately before and after laser pre-treatment, and at the start of surgery. Pupil behaviour during surgery was noted in descriptive terms, patient demographic, co-morbidities, eye measurements, suction on time, shifting time and laser energy levels were recorded. RESULTS: Seventy-three eyes were included. Average patient age was 74.84 ±â€¯9.1 years. Mean horizontal pupil sizes immediately before and after femto pre-treatment were 7.87 ±â€¯0.87 mm and 7.7 ±â€¯0.89 mm respectively (P < 0.0005). Mean horizontal pupil size at the start of surgery was 6.83 ±â€¯1.43 mm (P < 0.0005). Short capsulotomy-pupil distance (P = 0.01), shallower anterior chamber (P = 0.0012), smaller pre-operative pupil size (P = 0.045) and longer suction on time (P = 0.0019) were significantly associated with intra-operative miosis during FLACS. Sustained mydriasis was observed in eyes in whom topical diclofenac was used within 2 h of surgery. CONCLUSIONS: FLACS can result in significant pupil miosis. Eyes particularly at risk are ones with smaller pre-operative pupils and shallower anterior chambers and those subjected to longer suction on time. Well-timed NSAIDs application could be protective against this phenomenon.

Maximising Refractive Outcomes with an Extended Depth of Focus IOL.

OBJECTIVE: To assess the impact of the magnitude of preoperative and postoperative corneal astigmatism on refractive outcomes in patients undergoing cataract surgery or lens exchange with an extended depth of focus intraocular lens. To compare visual outcomes of steep and temporal on-axis corneal incisions. SETTING: Department of Ophthalmology, Blackrock Clinic, Dublin, Ireland. DESIGN: Prospective cohort analysis. METHODS: Fifty-three consecutive adult patients (94 eyes) undergoing routine phacoemulsification with Symfony IOL implantation were analysed. Exclusion criteria: targets for mini-monovision, incomplete data, other ocular pathology. Data were prospectively collected on pre- and postoperative refraction, keratometry, distance vision, near vision, surgical wound site and Surgically Induced Astigmatism (SIA). RESULTS: The average postoperative monocular Uncorrected Distance and Near visual acuities (UDVA and UNVA) were 0.12 LogMAR (± 0.1) (6/7.5+1) and 0.34 LogMAR (± 0.09) respectively. The average binocular UDVA and UNVA were 0.05 (± 0.07) and 0.29 LogMAR (± 0.06) respectively. Low levels of preoperative corneal astigmatism (0-0.99 D) were associated with better LogMAR UDVA and UNVA when compared with higher levels (> 0.99 D): 0.11 (CI 0.103-0.107) vs. 0.206 (CI 0.122-0.290) (p =0.015, CI 95%) and 0.33 (CI 0.316 - 0.356) vs. 0.39 (CI 0.34-0.43) (p =0.034, CI 95%) respectively. When patients with steep on-axis corneal incisions were compared with temporal on-axis corneal incisions, no difference was detected in visual outcome or SIA. CONCLUSION: The Symfony IOL is an effective surgical means of addressing presbyopia and reducing postoperative spectacle dependence. We stress caution when offering potential spectacle independence for patients with over 1D of preoperative corneal astigmatism as these patients achieve statistically significantly inferior and less predictable visual results.

Changes in ocular biomechanics after femtosecond laser creation of a laser in situ keratomileusis flap.

PURPOSE: To evaluate ocular biomechanical parameters with the Corvis ST, a noncontact tonometer combined with an ultra-high-speed Scheimpflug camera, before and after creation of a femtosecond laser-created laser in situ keratomileusis (LASIK) flap. SETTING: Private practice, Siena, Italy. DESIGN: Prospective consecutive study. METHODS: Right eyes of patients having LASIK were assessed with the dynamic Scheimpflug camera before and after femtosecond laser (LDV Z4) flap creation but before mechanical flap lifting. RESULTS: Twenty-eight eyes of 28 patients were evaluated. Before flap creation, the mean values on the dynamic Scheimpflug camera were intraocular pressure (IOP), 15.04 mm Hg ± 3.99 (SD); central pachymetry, 550.8 ± 101.0 µm; applanation 1 length, 1.721 ± 0.134 mm; applanation 2 length, 1.674 ± 0.287 mm; applanation 1 velocity, 0.126 ± 0.031 m/s; and deflection amplitude, 1.039 ± 0.141 mm. After flap creation, the mean values were IOP, 16.10 ± 3.11 mm Hg (95% confidence interval [CI], 0.44-1.78; P < .05); central pachymetry, 561.8 ± 35.9 µm (95% CI, -28.9 to 50.9; P = .21); applanation 1 length, 1.789 ± 0.1492 mm (95% CI, 0.003-0.134; P < .05); applanation 2 length, 1.759 ± 0.259 mm (95% CI, -0.005 to 0.173; P = .08); applanation 1 velocity, 0.136 ± 0.022 m/s (95% CI, 0.001-0.017; P < .05); and deflection amplitude, 1.029 ± 0.151 mm (95% CI: -0.043 to 0.025; P = .34). CONCLUSION: The dynamic Scheimpflug camera showed changes in biomechanical properties after femtosecond creation of a LASIK flap as indicated by an increased applanation 1 length and applanation 1 velocity. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Femtosecond-assisted laser in situ keratomileusis for consecutive hyperopia after radial keratotomy.

PURPOSE: To evaluate femtosecond-assisted laser in situ keratomileusis (LASIK) for the treatment of hyperopic shift after radial keratotomy (RK). SETTING: Private practice, Siena, Italy. DESIGN: Prospective case series. METHODS: Eyes with a spherical equivalent (SE) of +1.0 diopters (D) to +4.0 D after RK with 6 or 8 incisions had LASIK. The flap (nominal thickness 130 µm) was created with a femtosecond laser (LDV Z2); the refractive ablation was performed with an excimer laser (217P). The flap was dissected in a centrifugal fashion along previous RK cuts. RESULTS: Eighteen eyes of 10 patients were treated. Preoperatively, the mean defocus equivalent was 3.13 diopters (D) ± 0.71 (SD); the corrected distance visual acuity (CDVA) was 0.09 ± 0.06 logMAR. At 9 months, the mean defocus equivalent was 0.51 ± 0.47 D (P < .05), with 13 eyes (72%) having 0.50 D or less of defocus equivalent and 16 eyes (89%) having 1.0 D or less of defocus equivalent. The mean CDVA was 0.04 ± 0.06 logMAR (P < .05). No lines of logMAR CDVA were lost. The mean uncorrected distance visual acuity was 0.11 ± 0.10 logMAR. The safety index was 1.11; the efficacy index was 0.97. No retreatments were performed. Flap complications were limited to an RK incision opening larger than 2 mm in 3 eyes and 1 case of a small, self-limiting epithelial ingrowth. CONCLUSION: Laser in situ keratomileusis with a low-energy femtosecond laser was a safe and effective approach to treat post-RK hyperopia, causing no relevant inflammation. FINANCIAL DISCLOSURE: Neither author has a financial or proprietary interest in any material or method mentioned.

Femtosecond laser-assisted hyperopic laser in situ keratomileusis with tissue-saving ablation: analysis of 800 eyes.

PURPOSE: To evaluate the results and complications of hyperopic laser in situ keratomileusis (LASIK) with a low-energy femtosecond laser and non-custom tissue-saving ablation profile. SETTING: Private practice, Siena, Italy. DESIGN: Case series. METHODS: Hyperopic eyes with a spherical equivalent (SE) between +1.0 and +6.5 diopters (D) had LASIK. The flap (nominal thickness 110 µm) was created with a Ziemer LDV Z2 femtosecond laser and the refractive ablation performed with a Technolas 217P excimer laser in tissue-saving mode. RESULTS: Eight hundred eyes of 413 patients were treated. The mean preoperative values were SE, +3.41 D ± 1.16 (SD); defocus equivalent, 4.20 ± 1.33; corrected distance visual acuity (CDVA), 0.07 ± 0.08 logMAR. At 9 months, the mean SE was -0.06 ± 0.26 D and the mean defocus equivalent 0.68 ± 0.62 (both P<.05). The defocus equivalent was 0.50 D or less in 594 eyes (74.3%) and 1.00 D or less in 707 eyes (88.4%). The mean CDVA was 0.07 ± 0.06 logMAR; 3 eyes (0.4%) lost 2 lines of CDVA and 58 eyes (7.3%) lost 1 line. The mean uncorrected distance visual acuity was 0.16 ± 0.13 logMAR. The safety index was 1.0 and the efficacy index, 0.8. The mean root-mean-square induced primary spherical aberration was 0.65 µm and the mean induced primary coma, 0.24 µm (both P<.05). CONCLUSIONS: The low incidence of femtosecond-related complications was associated with good predictability, safety, and a low retreatment rate. The mean flap was 7 µm thicker than expected. FINANCIAL DISCLOSURES: The author has no financial or proprietary interest in any material or method mentioned.

Incidence of dislocated and subluxed iris-fixated phakic intraocular lens and outcomes following re-enclavation.

BACKGROUND: The purpose of this study was to establish the incidence of re-enclavation of iris-fixated phakic intraocular lenses in our centre and evaluate outcomes following re-enclavation. DESIGN: Retrospective observational case series. Single surgeon, hospital setting. PARTICIPANTS: Six hundred and nine patients (1218 eyes) implanted with iris-fixated phakic intraocular lenses between 2000 and 2011. METHODS: Eyes requiring re-enclavation were identified, and outcome measures were evaluated 12 months following re-enclavation. MAIN OUTCOME MEASURES: Rate of re-enclavation, uncorrected distance visual acuity and manifest refractive spherical equivalent were measured 12 months following re-enclavation. RESULTS: Twenty-five eyes (2% of eyes overall) of 20 patients required re-enclavation of a dislocated or subluxed phakic intraocular lens. Eight cases (32%) dislocated secondary to trauma and 17 (68%) subluxed spontaneously. No significant difference was detected (P = 0.59) in uncorrected distance visual acuity (logMAR equivalent) 12 months post-re-enclavation (0.18 ± 0.04) compared with that recorded 6 months post-initial uneventful phakic intraocular lens implantation (0.10 ± 0.06). No significant difference was detected (P = 0.95) in mean manifest refractive spherical equivalent 12 months post-re-enclavation (-0.59D ± 0.29D) compared with that recorded 6 months post-initial phakic intraocular lens implantation (-0.57D ± 0.17D). Following re-enclavation, mean endothelial cell count was 2627 ± 101 cells/mm(2) 12 months postoperatively in 16 eyes. This did not differ significantly from that recorded 6 months post-initial phakic intraocular lens implantation in these eyes (P = 1). CONCLUSION: Dislocation and subluxation of iris-fixated phakic intraocular lenses may occur secondary to trauma or spontaneously because of inadequate iris enclavation. Re-enclavation can be carried out successfully with no significant adverse effect on clinical outcomes.

Near visual acuity following hyperopic photorefractive keratectomy in a presbyopic age group.

Purpose. To assess near visual acuity in a presbyopic age group following hyperopic photorefractive keratectomy (PRK). Setting. Private practice in Siena, Italy. Methods. In this retrospective single-surgeon comparative study, PRK with mitomycin C was performed to correct hyperopia using Bausch & Lomb 217z laser for 120 eyes of 60 patients in the presbyopic age group (mean spherical equivalent SE +2.38 D ± 0.71 D and mean age 52 ± 5.09). 120 eyes of 60 age-matched controls (mean age 54 ± 5.09) had their unaided near vision measured. Results. At 12 months mean SE was -0.10 D ± 0.27 D in the PRK group. Mean best corrected visual acuity (BSCVA) was 0.005 ± 0.022 log MAR; 2 eyes lost ≥0.1 log MAR. Mean uncorrected visual acuity was 0.04 ± 0.077 log MAR. Mean distance corrected near visual acuity (DCNVA) in the PRK group was J3.73 ± 1.06. This was statistically better (P < 0.05) than the mean unaided near visual acuity in the control group J4.07 ± 1.08. Conclusion. PRK was found to be safe, predictable, and an effective way of correcting hyperopia in this age group. It was also found to give better than expected near vision.

Early flap displacement after LASIK.

PURPOSE: To evaluate the risks of flap displacement after LASIK. DESIGN: Retrospective case series. PARTICIPANTS: We included 41 845 consecutive adults who underwent LASIK surgery at Optical Express in the United Kingdom, including 81 238 eyes, of which 14 555 were hyperopic and 66 681 myopic or mixed astigmatic. We treated 57 241 eyes with the IntraLase FS-60 femtosecond laser and 23 997 with the Moria S.A. ONE Use-Plus automated microkeratome. METHODS: We calculated the incidence of all flap displacements in the study population during an observational time period of ≥12 months after surgery. Independent variables were entered into logistic regression models to identify risk factors. Postoperative outcomes were assessed. MAIN OUTCOME MEASURES: The incidence and odds ratios (OR) of flap displacement in the study population and in categories of refractive error and flap surgery technique. RESULTS: The incidence of flap displacements was 10 in 81 238 LASIK procedures (0.012%), including 8 hyperopic eyes (0.055%) and 2 myopic eyes (0.003%). All flap displacements occurred within 48 hours of surgery and none were preceded by ocular trauma. They were classified as "early flap displacements" (EFD). The incidence of EFD after microkeratome surgery was 0.033% (n = 8), and after femtosecond laser it was 0.003% (n = 2). In hyperopic eyes having microkeratome surgery, the incidence was 0.179% (n = 7). In a logistic regression model, the strongest predictor of EFD after LASIK was hyperopia, recording an OR of 19.29 (P<0.001). The OR of developing an EFD after microkeratomy was 10.53 times higher than after femtosecond laser (P<0.005). In hyperopes, the OR of an EFD was 18.87 times higher after microkeratomy than after femtosecond treatment. Four of 10 displaced flaps needed secondary surgery, and 1 eye lost 2 lines of best-corrected visual acuity. CONCLUSIONS: The incidence of flap displacements during a 12-month period after LASIK was extremely low (0.012%). Although the small number of displacements with the femtosecond laser limits conclusions, the risk of EFD was higher after microkeratome surgery than femtosecond laser.

Effect of tear hyperosmolarity and signs of clinical ocular surface pathology upon conjunctival goblet cell function in the human ocular surface.

PURPOSE: To investigate the effect of tear hyperosmolarity and signs of clinical ocular surface pathology on conjunctival goblet cell population. METHODS: 111 participants were assessed using tear osmolarity (TO) measurements and a comprehensive selection of clinical ophthalmic tests. The resultant clinical database was assessed for evidence of patterns of composite increasing pathology. The total, filled, and empty goblet cell numbers were measured: total number of goblet cells as per cytokeratin 7 (CK7) immunofluorescence and number of filled goblet cells as per periodic acid Schiff's reagent (PAS) or lectin helix pomatia agglutinin (HPA). Goblet cell profile was correlated with composite clinical pathologic grades. RESULTS: No significant correlation was found between TO and goblet cell number or function (as indicated by number of filled or unfilled goblet cells). Distinct composite clinical pathologic groups 0-IV with increasing pathology were created based on the frequency of positive pathologic signs, which adhered to the Dry Eye Workshop purported mechanism. Only in group IV was there significantly increased mean tear osmolarity of 344 mOsm/L (P < 0.000) along with significantly decreased empty goblet cell number (CK7+ and HPA-) compared to filled (CK7+ and HPA+, P = 0.000). When the number of filled goblet cells (PAS+) was analyzed there was significant increase in tear osmolarity for the two most severe grades; 3 and 4. CONCLUSIONS: The goblet cell population does not appear to be affected by isolated tear hyperosmolarity. Hyperosmolarity when combined with other ocular surface pathology or inflammation alters the goblet cell population.

Femtosecond laser in situ keratomileusis versus conductive keratoplasty to obtain monovision in patients with emmetropic presbyopia.

PURPOSE: To compare visual outcomes, complications, and patient satisfaction after femtosecond laser in situ keratomileusis (LASIK) and conductive keratoplasty (CK). SETTING: Private laser clinics, Reading and Southampton, United Kingdom. METHODS: In this retrospective consecutive single-surgeon comparative study, presbyopic emmetropia was treated with femtosecond LASIK or CK to achieve monovision by targeting -1.50 diopters (D) of myopia in the nondominant eye after a successful monovision contact lens trial. The CK treatments were performed with a ViewPoint CK system using the light-touch technique. The femtosecond LASIK was performed using an IntraLase FS/FS30 and EC-5000 platform with OPDCAT wavefront treatment. RESULTS: The mean spherical equivalent 12 months postoperatively was -1.63 D +/- 0.68 (SD) in the femtosecond LASIK group and -0.97 +/- 0.82 D in the CK group (P<.001). The mean vector value of astigmatism at 12 months was 0.32 +/- 0.32 D and 1.00 +/- 0.75 D, respectively (P<.0001). The mean induced higher-order aberration (HOA) was 0.45 +/- 0.28 microm in the femtosecond LASIK group and 1.13 +/- 0.25 microm in the CK group (P<.0001). The retreatment rate was 3% after femtosecond LASIK and 50% after CK (P<.0001). On a questionnaire administered at 12 months, 20 patients (62.5%) in the femtosecond LASIK group and 11 patients (34.4%) in the CK group reported being satisfied (P = .02). CONCLUSIONS: In emmetropic presbyopic cases, femtosecond LASIK monovision provided stable correction with less induced astigmatism and HOA. Eyes with CK monovision had regression and induced astigmatism.

Transepithelial corneal collagen cross-linking in keratoconus.

PURPOSE: To evaluate the clinical effects of transepithelial corneal cross-linking (CXL) on keratoconic eyes pre-treated with substances enhancing epithelial permeability. METHODS: Prospective, consecutive, single-masked, paired-eye study on 51 patients. The eye with more severe keratoconus was treated; the fellow eye served as the control. Gentamicin, benzalkonium chloride, and ethylenediaminetetraacetic acid were instilled for 3 hours, then oxybuprocaine for 30 minutes. Riboflavin 0.1% in 20% dextran T500 and oxybuprocaine were instilled for 30 minutes. Finally, ultraviolet A irradiation to the central 7.5 mm of the cornea was applied for 30 minutes, while riboflavin was instilled every 5 minutes. RESULTS: Mean corrected distance visual acuity improved by 0.036 logMAR after CXL and worsened by 0.039 logMAR in the control eyes (P<.05). Safety index was 1.05 after CXL and 0.96 in the control group. Mean spherical equivalent refraction decreased by 0.35 D (less myopic) after CXL and increased by 0.83 diopters (D) in the control eyes (P<.05). Mean apex curvature on tangential videokeratography increased by 0.51 D after CXL and by 1.61 D in the control eyes (P=.16). Mean average simulated keratometry decreased by 0.10 D after CXL and increased by 0.88 D in the control eyes (P<.05). Mean index of surface variance increased (worsened) by 0.9 after CXL and 5.3 in the control eyes (P<.05). Mean endothelial cell density was unchanged. CONCLUSIONS: A limited but favorable effect of transepithelial CXL was noted on keratoconic eyes, without complications. The effect appears to be less pronounced than described in the literature after CXL with de-epithelialization.