Significant Difference In Uncorrected Visual Acuity Research Articles

Topography-guided transepithelial corneal collagen cross-linking by sequential ultraviolet A irradiation in different diameters for progressive keratoconus in adults

Objective: To compare the efficacy and safety of a novel customized topography-guided transepithelial corneal collagen cross-linking (TG-CXL) procedure by sequential ultraviolet A irradiation in different diameters and conventional transepithelial corneal collagen cross-linking (TE-CXL) in adult patients with progressive keratoconus. Methods: A prospective cohort study was conducted. Adult patients diagnosed with progressive keratoconus in the Affiliated Xiamen Eye Center of Xiamen University were continuously recruited and randomly assigned to receive the TG-CXL or TE-CXL procedure from March 2020 to March 2021. Patients in the TE-CXL group were irradiated in the central 9-mm zone of the cornea (total energy, 7.2 J/cm2; irradiance, 45 mW/cm2), while patients in the TG-CXL group were first irradiated with the protocol used in the TE-CXL group, and further irradiated in the central 6-mm zone (total energy, 3.6 J/cm2; irradiance, 9 mW/cm2). The subjective symptom of pain and corneal fluorescein sodium staining were scored within postoperative 3 days. Slit lamp examination, measurements of uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), corneal topography, anterior segment optical coherence tomography, in vivo corneal confocal microscopy, corneal endothelial cell count, and non-contact tonometry were performed before surgery and at 3, 6, and 12 months after surgery. Results: A total of 66 patients were enrolled (mean age, 23.0±3.3 years old), with 33 patients (33 eyes) in each group. No statistically significant differences were found in age, gender, and maximum keratometry (Kmax) between the two groups (P>0.05). On day 1 after surgery, the average pain score of the TG-CXL group (2.21±0.45) was significantly higher than that of the TE-CXL group (1.32±0.33) (P<0.05). The pain was rapidly alleviated in both groups on days 2 and 3. On days 1 and 2, the corneal fluorescein sodium staining scores in the TG-CXL group (4.15±0.83 and 2.21±0.60, respectively) were significantly higher than those in the TE-CXL group (1.76±0.56 and 0.85±0.51, respectively, P<0.001), while there was no significant difference between the two groups at day3 (P=0.184). The UCVA and BCVA of the TG-CXL group at 3, 6, and 12 months after surgery were significantly improved when compared with the baseline. At 3, 6, and 12 months, the BCVA (LogMAR) of the TG-CXL group (0.21±0.15, 0.22±0.16, and 0.22±0.16, respectively) were significantly improved when compared with those of the TE-CXL group(0.32±0.15, 0.34±0.15, and 0.36±0.16, respectively, P<0.01). However, there was no significant difference in UCVA between groups at any time point after surgery (P>0.05). The spherical and cylindrical power values of the TG-CXL group were improved when compared with the baseline (P<0.05). However, no significant difference in spherical power values was found between the two groups at any time point after surgery (P>0.05). Meanwhile, there were significant differences in cylindrical power values between the two groups at 6 and 12 months after surgery (P<0.05). The Kmax in the TG-CXL group was improved at all of the time points after surgery when compared with the baseline (P<0.001), while no significant difference in Kmax was found at any time point after surgery in the TE-CXL group when compared with the baseline (P>0.05). At 6 and 12 months after surgery, the Kmax values in the TG-CXL group were significantly lower than the TE-CXL group (P<0.05). No significant differences were found in flat keratomety, steep keratometry, the minimal thickness of the cornea, endothelial cell density, and intraocular pressure between the two groups at any time point after surgery (P>0.05). Within one month after surgery, optical coherence tomography revealed the increased density in the anterior stroma in both groups. In most patients in the TG-CXL group, a demarcation line was visible in the central and para-central corneal stroma, representing a clear and continuous, high-signal arc-shaped linear structure, which was deeper in the central cornea than the para-central cornea. In contrast, a demarcation line, fuzzy and focally discontinuous, was visible only in a few patients in the TE-CXL group, with an almost uniform depth in the central and the para-central cornea. Confocal microscopy demonstrated an apparent mesh-like cross-linked collagen structure in the superficial and intermediate corneal stroma at all time points after surgery in the TG-CXL group, with thickening stromal collagen fibers and an increased number of interconnections. In contrast, the mesh-like structure and number of interconnections in the superficial corneal stroma were significantly reduced at 12 months after surgery in the TE-CXL group, with no cross-linking structure in the intermediate corneal stroma at any time point after surgery. No serious complications such as corneal infection, sterile corneal ulcer, and persistent epithelial defect were observed in both groups during the follow-up of 12 months. Conclusions: The TG-CXL procedure by sequential irradiation in two different diameters with ultraviolet A light was effective and safe in the management of progressive keratoconus in adults, achieving significant refractive improvement. This might be a good technical alternative for refractive corneal cross-linking surgery.

23G Minimally Invasive Vitrectomy Combined with Glaucoma Drainage Valve Implantation and Phacoemulsification Cataract Extraction for Neovascular Glaucoma Secondary to Proliferative Diabetic Retinopathy with Vitreous Hemorrhage.

Objective To evaluate the clinical efficacy of the combined application of 23G minimally invasive vitrectomy, glaucoma drainage valve implantation, and phacoemulsification cataract extraction in the treatment of neovascular glaucoma (NVG) secondary to proliferative diabetic retinopathy (PDR) combined with vitreous hemorrhage (VH). Methods Eighty-three patients (91 eyes) with PDR diagnosed as NVG phase III complicated with VH from June 2018 to May 2020 were selected as the study subjects. The subjects were randomly divided into 3 groups: group A was treated with 23G minimally invasive vitrectomy combined with glaucoma drainage valve implantation; group B was given 23G minimally invasive vitrectomy combined with phacoemulsification cataract extraction; and group C was treated with 23G minimally invasive vitrectomy combined with glaucoma drainage valve implantation and phacoemulsification cataract extraction. The uncorrected visual acuity (UCVA), intraocular pressure (IOP), and iris neovascularization (INV) scores were recorded and compared among the 3 groups before and after operation, and then the postoperative pain relief and complications were observed. Results Through observation, there was no significant difference in the UCVA, IOP, and INV scores in the 3 groups before operation. After the operation, the UCVA, IOP, and INV scores of the 3 groups were significantly lower than those before operation. After operation, the UCVA of the 3 groups increased first and then decreased, and it improved most significantly in the 3rd month after operation and decreased in the 4th month after operation. There were significant differences in UCVA among the 3 groups at each time point after operation. From the 1st day to the 6th month after operation, the IOP of the 3 groups showed an upward trend, and there was no significant difference among the 3 groups in IOP at each time point after operation. At the 1st, 3rd, and 6th months after operation, the INV score of group A and group B was higher than that of group C. There was no significant difference in the INV score between group A and group B. The incidence of complications was not significantly different among the 3 groups. Conclusion 23G minimally invasive vitrectomy, glaucoma drainage valve implantation, and phacoemulsification cataract extraction can effectively improve the UCVA, IOP, and INV scores of NVG secondary to PDR with VH, and the combined application of the 3 methods has better security.

Comparison of the efficacy of lotrafilcon B and comfilcon A silicone hydrogel bandage contact lenses after transepithelial photorefractive keratectomy.

At completion of transepithelial photorefractive keratectomy (t-PRK) surgery, the eye is usually fitted with a bandage contact lens to reduce discomfort and promote epithelial healing. This study aimed to compare the outcomes of eyes fitted with lotrafilcon B versus comfilcon A, silicone hydrogel bandage contact lenses after t-PRK for the correction of low to moderate myopia, with or without astigmatism. In this comparative, prospective study, patients with myopia < -6 D with or without astigmatism (< 1.75 D), who underwent t-PRK between January and June 2018, were randomly allocated to the lotrafilcon B and comfilcon A groups. Preoperative characteristics, including age, sex, eye treated, uncorrected visual acuity (UCVA), best-corrected visual acuity, mesopic pupil size, central corneal thickness, and refractive error were recorded. Postoperatively, pain score, UCVA, and corneal epithelial defect size on days 1, 4, and 7 were compared between the two groups. Twenty-nine eyes were included in each group. Demographic characteristics and preoperative measurements were similar between the two groups. UCVA was significantly improved on day 7 as compared to day 1 in the comfilcon A group (P = 0.03), but remained the same in the lotrafilcon B group (P = 0.70) as on day 1 postoperatively. There was no significant difference in UCVA between the two groups at any follow-up visits (all P > 0.05). The pain score on the first postoperative day was significantly higher in the lotrafilcon B-fitted eyes than in the comfilcon A group (P < 0.001), but was significantly reduced in both groups compared to day 1 (both P < 0.001). The epithelial defect in the comfilcon A group was significantly greater than in the lotrafilcon B group (P < 0.001) at day 1 postoperatively, with significant improvement in both groups (both P < 0.001). Healing responses were better with lotrafilcon B than with comfilcon A bandage contact lenses. The patients had a greater mean pain score with lotrafilcon B than with comfilcon A lenses on the first postoperative day, yet the final outcome was comparable between the two groups. We did not encounter any postoperative complications related to contact lens wear.

Comparison of corneal aberrations and refractive outcomes after small-incision lenticule extraction and femtosecond-assisted laser-assisted in situ keratomileusis.

To retrospectively compare the short-term refractive outcomes and corneal aberrations after small-incision lenticule extraction (SMILE) and femtosecond-assisted laser-assisted in situ keratomileusis (FS-LASIK) combined with smart pulsetechnology (SPT) in patients with compound myopicastigmatism. A total of 91 eyes (91 patients) were included, 43eyes in FS-LASIK group and 48 eyes in the SMILE group. Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), refractive results and corneal topography were evaluated 1 and 3months postoperatively. Corneal aberrations of anterior corneal surface were calculated from the topography data over 6mm-diameter. There was no significant difference in UCVA, BCVA, and refractive results between the two groups. There were no statistical difference in TIA (target induced astigmatism), SIA (surgery induced astigmatism), DV (difference vector), ME (magnitude of error), AE (angle of error), AE (absolute value) and CI (correction index) between both groups at 1 and 3months. Coma and spherical aberration improved in all the patients in both groups at 1 and 3months postoperatively. The amount of induced spherical aberrations was higher in FS-LASIK group compared to SMILE group. Both FS-LASIK and SMILE achieved similar refractive outcomes in patients with myopia and compound myopic astigmatism. FS-LASIK combined with SPT resulted in higher spherical aberration than SMILE in early postoperative period.

Comparison of early visual quality in patients with moderate myopia using different optical zones in small incision lenticule extraction (SMILE)

BackgroundThe early visual qualities of patients with moderate myopia were evaluated after small incision lenticule extraction (SMILE) using different optical zones.MethodsIn this retrospective case study, 27 cases (51 eyes) were selected, including 10 cases in Group A (19 eyes), 6.6–6.8 mm in the optical zone, 10 cases in Group B (19 eyes), 6.4–6.5 mm in the optical zone, and 7 cases in Group C (13 eyes),6.1–6.3 mm in the optical zone. The following items were examined preoperatively and 1 month postoperatively: uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical, cylinder, central corneal thickness (CCT), corneal mean curvature (CMC), total ocular aberrations (TA), total low order aberrations (tLOAs), defocus, astigmatism and total high order aberrations (tHOAs), spherical, coma, trefoil, modulation transfer function (MTF), MTFcutoff, SR, objective scatter index (OSI), point scatter function at 50 and 10% (PSF50%, PSF10%), and contrast visual acuity of 100, 20, and 9% (VA100%, VA20%, and VA9%). We compared the three groups by Kruskal-Wallis test. Wilcoxon signed ranks test was used for each group before and 1 month after surgeries. P< 0.05 was considered statistically significant.ResultsThere was no significant difference in UCVA, BCVA, CCT, cylinder, and CMC in three groups preoperatively and 1 month postoperatively (P> 0.05). Comparison of the aberrations of the three groups showed statistically significant difference only in TA, tLOA, defocus, astigmatism and SA preoperatively, and trefoil 1 month postoperatively(P< 0.05). The postoperative TA, tLOAs, defocus, astigmatism and trefoil of the three groups were lower than those before surgeries (P< 0.05). The postoperative tHOAs of Group B and C was lower than those before surgeries (P< 0.05). The MTF results showed that before surgeries, there were significant differences in three groups (P< 0.05) in spatial frequencies 5~15 cycles per degree (cpd), and no differences in 20~30 cpd(P> 0.05), while no difference were observed in all spatial frequencies postoperatively (P> 0.05). Comparing the preoperative and postoperative MTF values for each group, the results showed that there was a significant difference in Group C at 5~20 cpd after surgeries(P< 0.05). There was no significant difference in MTFcutoff, SR, OSI, PSF50%, PSF10%, VA100%, VA20%, and VA9% in the three groups preoperatively (P> 0.05). One month after surgeries, higher VA9% values were measured for Group C compared to Group A and B (P < 0.05). There was no significant difference in each group before and after surgeries (P> 0.05).ConclusionSMILE could improve the visual qualities of patients with moderate myopia. Reducing the surgical optical zone will only affect night vision slightly.

The effect of thin lenticule versus thick lenticule (a cut-off value of 55 micrometer) on the outcome of SMILE in low myopia

Objectives: In the current study, the aim was to evaluate the effect difference in lenticule thickness SMILE cases (≤ 55 µm versus &gt; 55 µm) on the visual outcome in a cohort of 61 patients with low myopia (≤3.0 diopters)&#x0D; Methods: The current prospective cohort study included 61 patients undergoing SMILE refractive procedure during the period extending from November the 14th 2019 through June the 14th 2020, a total of 99 eyes. The study was conducted in Ibsar ophthalmology surgery centre "private medical centre" in the wholly Najaf city, mid-Euphrates region of Iraq. The cases enrolled in the study were all operated on by the same ophthalmologist. According to lenticule thickness, eyes were classified into two groups, (≤ 55 µm versus &gt; 55 µm). The main outcome variable was visual acuity postoperative within two short period of time, one week and 3 months.&#x0D; Results: Comparison of visual acuity between patients with lenticule thickness of ≤ 55 µm and patients with lenticule thickness of &gt; 55 µm was shown in table 6. There was no significant difference in UCVA (uncorrected visual acuity) (P = 1.000), significant difference in BCVA (best corrected visual acuity) (better with lenticule thickness of ≤ 55 µm) (P = 0.037), no significant difference in VAAS (visual acuity after surgery) (P = 0.065) and no significant difference in VA3M (visual acuity 3 months after surgery) (P = 0.599).&#x0D; Conclusion: Thin lenticule of less than or equal 55 micrometer to as low as 41 micrometer can be chosen for SMILE with efficacy and safety comparable to that of thicker lenticule provided that the operation is done by well trained and skilled refractive surgeon.

Clinical study on topography-guided laser ablation combined with accelerated corneal collagen cross-linking for early keratoconus

Objective: To study the safety and efficacy of topography-guided customized excimer laser subepithelial ablation combined with accelerated collagen cross-linking technique in treatment of early keratoconus. Methods: Ninteen patients(20 eyes) (13 males 14 eyes, and 6 females 6 eyes), aged 12 to 44 years (24.7±8.0) were diagnosed as keratoconus by three-dimensional corneal topography and tomography, clinical history and examinations, and classified as KC1~KC3. Based on the classical excimer laser subepithelial keratomileusis (LASEK) method, topography guided laser ablation was performed with an excimer laser system (WaveLight EX500). After laser ablation, the corneal stromal bed was immersed with 0.1% riboflavin for 10 minutes, and then was irradiated by ultraviolet light (Avedro KXL) at 30 mW/cm(2) for 4 minutes. All the patients were followed up for more than 12 months. The uncorrected visual acuity (UCVA), diopter, best corrected visual acuity (BSCVA), corneal topography, central corneal endothelial cell density (ECD), hexagonal cell percentage (HEX), coefficient of variation (CV) and other indicators were observed. For normal distribution variables, Dunnett-t test was used before and after operation, and Wilcoxon test was used for variables with abnormal distribution. And the complications were recorded. Results: There was no loss of BSCVA at 12 months postoperatively, 20% of the eyes had no change of BSCVA, and 15% of the eyes gained 1 line of BSCVA, 15% of the eyes gained 2 lines of BSCVA, 50% of the eyes gained 3 lines and more of BSCVA. There was no significant difference in UCVA, BSCVA, manifest refractive spherical equivalent (MRSE) and the cylinder at 3 months postoperatively (P>0.05). The BSCVA were significantly improved at 6 and 12 months postoperatively compared with those before operation (t=3.095, 3.079, <0.05). Although there was no significant difference in UCVA and MRSE, the cylinder was significantly reduced at 6 and 12 months postoperatively (t=-2.890, -2.435, P<0.05). Apex curvature (Kapex) and mean pupil power (MPP) within 4.5mm of central cornea decreased significantly (Z=-2.903, P<0.01; Z=-2.667, P<0.01). Even though the thinnest corneal thickness decreased from pre-operational (461.9±31.1) μm to post-operational (416.6±27.0) μm (Z=-3.059, P<0.01), the cornea became regular with keratometric asymmetry index of anterior corneal surface decreased (Z=-2.667, P<0.01). The corneal optical quality parameters were improved. There was no significant difference in ECD, HEX and CV at 12 months postoperatively (P>0.05). Twelve months after operation, grade 0, 0.5, 1 and 2 haze were seen on 20%, 55%, 20% and 5% corneas respectively. Conclusions: The topography guided excimer laser ablation combined with accelerated corneal collagen cross linking is safe and effective in treatment of early stage keratoconus. It can significantly improve corneal regularity while preventing keratoconus progression, so as to improve the best corrected visual acuity postoperatively. (Chin J Ophthalmol, 2019, 55: 904-910).

Effect of 0.05% Cyclosporine A on the Ocular Surface after Photorefractive Keratectomy

Purpose: To evaluate the effect of 0.05% cyclosporine A on the ocular surface after photorefractive keratectomy (PRK). Methods: This retrospective study included 50 patients who underwent PRK. Patients were divided into two groups: 25 patients in group I were treated with topical 0.05% cyclosporine A with conventional medication, and 25 patients in group II were treated with conventional medication. Visual acuity (VA), tear break-up time (BUT), fluorescein staining score (F-stain), Schirmer I test, and ocular surface disease index (OSDI) were evaluated before surgery and 2 weeks, 1 month, 2 months, and 3 months after surgery. Results: F-stain was significantly lower in group I than in group II at 2 weeks and 1 month (p < 0.05). There was no significant difference in uncorrected VA, BUT, Schirmer I test, or OSDI between the groups. However, group I showed a more effective pattern in dry eye. Conclusions: Combination treatment with 0.05% cyclosporine A was helpful for early ocular surface stability in patients with dry eye after PRK. J Korean Ophthalmol Soc 2016;57(5):710-717

Ocular findings among young men: a 12‐year prevalence study of military service in Poland

To determine the prevalence of ocular diseases among young men and to assess the main ocular causes reflecting discharge from military service in Poland. A retrospective review of the medical records of 105 017 men undergoing a preliminary examination for military service during the period 1993-2004. Sample size for the study was calculated with 99% confidence within an error margin of 5%. All of the study participants were White men of European origin, most of whom live or lived in Poland. Data regarding the vision status were assessed in 1938 eyes of 969 participants. Two groups were distinguished based on the age of the participants: group I aged 18-24 years, and group II aged 25-34 years. Presented visual impairment [visual acuity (VA)<20/40)] followed by colour vision defects were the most common ocular disorders, accounting for 13.2%. There were statistically significant differences in uncorrected VA as well as in the rates of particular refractive errors in between the age groups (p<0.05). The prevalence of glaucoma and ocular hypertension was significantly higher in older participants. Six hundred and sixty-seven (68.8%) participants examined medically in the study period were accepted for military service. However, 302 (31.2%) failed their examination and were temporarily or permanently discharged from duty. Fifty-two of them (17.2%) were discharged because of various ocular disorders. The most common causes were high refractive errors, which accounted for 38.5% of all the ocular discharges, followed by chronic and recurrent diseases of the posterior segment of the eye, which accounted for 19.2%. The prevalence of ocular disorders among young men in an unselected military population was closer to the results obtained in other population-based studies comprising both men and women in the same age group. High refractive errors followed by chronic and recurrent diseases of the posterior segment of the eye are important causes of medical discharges from military service in Poland.

Base curves of therapeutic lenses and their effects on post Epi-LASIK vision and pain: A prospective randomized clinical trial

To compare the efficacy of bandage contact lenses with two different base curves in promoting epithelial healing after epithelial laser in situ keratomileusis (epi-LASIK). A prospective, observer-masked study was conducted in 27 patients. Each patient randomly received one bandage contact lens with an 8.4-mm base curve in one eye and one with an 8.8-mm base curve in the fellow eye. Corneal epithelial status, pain score, spherical equivalent, and uncorrected visual acuity (UCVA) were examined during the first postoperative month. Corneal epithelial status, postoperative pain, and spherical equivalent were similar for both lenses during the first postoperative month. The eyes with lenses with an 8.8-mm base curve had better UCVA on postoperative day (POD) 4, but there was no significant difference in UCVA after POD 7. In the patients with preoperative low to moderate myopia and low keratometric values (<43.0 D), there was no significant difference in the postoperative UCVA between the lenses. On the other hand, in patients with preoperative high myopia and high keratometric values (> or =43.0 D), UCVA was better in eyes with lenses with an 8.8-mm base curve on POD 4. These findings suggest that the base curves of bandage contact lenses affect visual rehabilitation after epi-LASIK, particularly in patients with a steep cornea and high myopia.

Comparative evaluation of ‘flap on’ and ‘flap off’ techniques of Epi-LASIK in low-to-moderate myopia

Comparative evaluation of 'flap on' and 'flap off' techniques of Epi-LASIK in low-to-moderate myopia. Sixteen eyes of eight consecutive patients with myopia < or = 6 D were selected for this prospective, randomized, comparative, interventional case series. Epi-LASIK surgery was performed in all eyes. In one eye of each patient, the epithelial flap was retained after excimer laser ablation (flap on). In the fellow eye, the epithelial flap was discarded (flap off) after ablation. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), spherical equivalent (SEQ), postoperative pain score, time to epithelization, and corneal haze were recorded on postoperative visits. The mean preoperative SEQ in the two groups was -3.61+/-1.32 D (flap on) and -3.49+/-1.86 D (flap off; P=0.752). The mean follow-up period was 8.5+/-4.9 months. The mean pain score was comparable on all postoperative days except the second postoperative day when the group with flap off had a lesser mean pain score (P=0.053).Time for epithelial healing was 3.63+/-0.52 days in cases with flap off and 4.13+/-0.64 days in cases with flap on (P=0.113). Eyes with flap off had a better UCVA on the first postoperative day (0.19+/-0.11 logMAR) compared with eyes with flap on (0.41+/-0.28 logMAR; P=0.032). There was no significant difference in UCVA, BSCVA, SEQ, contrast sensitivity, corneal haze, and higher order aberrations at any other postoperative visit. There is no difference between flap on and flap off techniques of Epi-LASIK with regards to overall outcome of surgery.

Comparison of Epi-LASIK and Off-Flap Epi-LASIK for the Treatment of Low and Moderate Myopia

To compare the early postoperative course and the 1-year clinical results of off-flap Epi-LASIK and Epi-LASIK for the treatment of low and moderate myopia. Pilot double-masked, randomized, comparative study. Fifty-six patients (112 myopic eyes). Epithelium was separated in all eyes with the use of Centurion SES epikeratome (Norwood Abbey EyeCare, Vic, Australia). The first eye treated and surgical method in the first eye were randomized. One eye of each patient underwent standard Epi-LASIK, whereas in the contralateral eye, the epithelial sheet was not retained on the photoablated stroma (off-flap Epi-LASIK eyes). Mean preoperative spherical equivalent was -3.50+/-1.22 diopters (D; range, -1.75 to -6.37 D) in Epi-LASIK eyes and -3.61+/-1.22 D (range, -1.50 to -6.50 D) in off-flap Epi-LASIK eyes (P>0.05, paired Student t test). Excimer laser corneal ablation was performed using the Allegretto 200Hz (Wavelight Laser Technologie AG, Erlangen, Germany). Patients were followed up daily until the epithelial healing was complete and at 1, 3, 6, and 12 months. Epithelial healing time, subjective pain score, and uncorrected visual acuity (UCVA) were evaluated during the first postoperative days. Uncorrected visual acuity, spherical equivalent refraction, best spectacle-corrected visual acuity, haze scores, and wavefront aberrations were recorded at all subsequent intervals. Time of epithelial healing did not differ significantly in Epi-LASIK and off-flap Epi-LASIK eyes (4.76+/-0.84 days in Epi-LASIK eyes vs. 4.54+/-0.93 days in off-flap Epi-LASIK eyes). No significant difference in UCVA was found after the 2 techniques during the first postoperative days. Subjective pain score was lower in off-flap Epi-LASIK eyes at 2 postoperative hours, whereas no significant difference in pain scores was noted between the 2 techniques at the other intervals. There was no significant difference in spherical equivalent, line gain or loss, haze scores, and higher-order aberrations between Epi-LASIK and off-flap Epi-LASIK eyes at any interval. Uncorrected visual acuity was significantly better in Epi-LASIK eyes only at 6 months (-0.05+/-0.08 in Epi-LASIK eyes vs. 0.00+/-0.07 in off-flap Epi-LASIK eyes). Preoperative wavefront aberrations did not change significantly 1 year after either procedure. Epi-LASIK and off-flap Epi-LASIK had equal visual and refractive results for the treatment of low and moderate myopia in this study. Proprietary or commercial disclosure may be found after the references.

Stability of Wavefront Aberrations During the Daytime After 6 Months of Overnight Orthokeratology Corneal Reshaping

To evaluate the stability of wavefront aberrations during the daytime after 6 months of overnight orthokeratology corneal reshaping. A prospective study of 26 eyes using the Ultravision BE lens design during 6 months of overnight wear. Uncorrected visual acuity (UCVA), cycloplegic refraction, and wavefront aberrometry were measured at 8 AM (within 1 hour after awakening and removing lenses), 1 PM (5 to 6 hours after lens removal), and 6 PM (10 to 12 hours after lens removal). There was no significant difference in UCVA between 8 AM, 1 PM, and 6 PM (P=.383). Spherical power from wavefront aberrometry showed significant regression from 8 AM to 1 PM (P<.001) and stabilized near zero diopters. Total root-mean-square (RMS) increased and higher order aberration RMS and defocus (Z4) decreased between 8 AM and 1 PM (P<.001) but did not change for the rest of the day (P>.001). There was no statistically significant change in astigmatism (Z3 and Z5) (P=.449) and coma (Z7 and Z8) (P=.145) between 8 AM, 1 PM, and 6 PM. Spherical aberration (Z12) showed regression throughout the day (P<.001). After 6 months of overnight orthokeratology wear, some optical aberrations showed regression during the day. Despite no significant change in UCVA during 10 to 12 hours, there was a significant increase in defocus (Z4) within the first 5 hours after removing the orthokeratology lens and a decrease in spherical aberration (Z12) throughout the day.

Allergic conjunctivitis as a risk factor for laser in situ keratomileusis

Purpose: To analyze the effect of allergic conjunctivitis (AC) on the outcome of laser in situ keratomileusis (LASIK) in myopic eyes. Setting: Minamiaoyama Eye Clinic, Tokyo, Japan. Methods: Patients who had LASIK were divided into 2 groups: those with AC (84 eyes of 49 patients; the allergic group) and those without AC (140 eyes of 77 patients; the nonallergic group). Allergic conjunctivitis was diagnosed clinically by symptoms of eye itching and clinical findings such as papillary proliferation on the tarsal conjunctiva. Preoperative and postoperative uncorrected visual acuity (UCVA) and refraction and intraoperative and postoperative complications were compared. Results: There were no significant differences in UCVA and refraction between the 2 groups. No complications were observed in the allergic group. Intraoperative conjunctival chemosis (3 eyes of 2 patients) and a postoperative epithelial defect that resulted in epithelial ingrowth (1 eye) were observed in the nonallergic group. Conclusion: The findings suggest that AC is not a risk factor for LASIK.

Prospective Randomized Comparison of Simultaneous and Sequential Bilateral Photorefractive Keratectomy for the Correction of Myopia

To evaluate the efficacy and safety of simultaneous bilateral photorefractive keratectomy (PRK). There were 52 patients (104 eyes) with myopia less than -6 diopters entered in this prospective trial and randomized to simultaneous or sequential bilateral PRK. Main outcome measures were uncorrected visual acuity (UCVA), percentage of eyes within +/-0.5 D of attempted outcome, present pain intensity (PPI) and total pain rating index (PRI(R)T) scores resulting from McGill the Pain Questionnaire, subjective symptoms, haze, and patient satisfaction. Follow-up extended to 14 months. There was no significant difference in UCVA (P=0.996) and percentage of eyes within +/-0.5 D of attempted correction (P=0.932). Present pain intensity and PRI(R)T scores were significantly higher in the sequential group (P=0.037; P=0.034). The percentage of satisfied patients after bilateral PRK was significantly higher in the simultaneous group (P=0.036). Simultaneous bilateral PRK was safe and effective, without any significant difference from sequential treatment.