Three-Year Results of Simultaneous Transepithelial Phototherapeutic Keratectomy and Conventional Photorefractive Keratectomy (Cretan Protocol Plus) Followed by Corneal Crosslinking for Keratoconus.

PURPOSE: The aim of this study was to present the 3-year outcomes after simultaneous transepithelial phototherapeutic keratectomy (t-PTK) and conventional photorefractive keratectomy (PRK) followed by corneal crosslinking (CXL) for keratoconus. METHODS: In this prospective, interventional case series, patients with progressive keratoconus underwent simultaneous t-PTK and conventional PRK followed by CXL (Cretan protocol plus). Visual, refractive, and topographic outcomes were evaluated along with endothelial cell density (ECD) preoperatively and at 1, 2, and 3 years postoperatively. RESULTS: Twenty-two patients (31 eyes) were enrolled. No intraoperative or postoperative complications were observed in any of the patients. Logarithm of the minimum angle of resolution (logMAR) mean uncorrected and mean corrected distance visual acuity improved from 0.81 ± 0.40 and 0.18 ± 0.21 preoperatively to 0.38 ± 0.33 ( P < 0.001) and 0.06 ± 0.12 ( P < 0.001) at 3-year follow-up. Mean spherical equivalent improved from -5.39 ± 3.89 diopters (D) preoperatively to -2.29 ± 2.65 D ( P < 0.001) at 3 years postoperatively. Mean corneal astigmatism reduced from -4.70 ± 2.86 D preoperatively to -3.55 ± 2.45 D ( P = 0.001) at 3 years postoperatively. No ECD alterations were observed throughout the 3-year follow-up ( P > 0.05). CONCLUSIONS: Simultaneous t-PTK and conventional PRK followed by CXL seems to be an effective and safe treatment for progressive keratoconus over 3-year follow-up.

Small incision lenticule extraction retreatment in a patient with high residual refractive error after photorefractive keratectomy: A case report.

A 36-year-old male underwent uneventful small incision lenticule extraction (SMILE) for the correction of his high residual refractive error 12 years after photorefractive keratectomy (PRK). Preoperatively, uncorrected distance visual acuity (UDVA) was counting fingers in both eyes. Corrected distance visual acuity was 20/20 in the right and 20/30 in the left eye due to amblyopia. One month after SMILE, UDVA was 20/20 and 20/30 in the right and left eye, respectively; post-PRK corneal haze had reduced. During the 4-year follow-up, UDVA remained stable and there were no complications. SMILE could be a good alternative approach for retreatment in post-PRK patient.

Accuracy of dynamic contour tonometry, Goldmann applanation tonometry, and Tono-Pen XL in edematous corneas.

PURPOSE: To investigate in vitro the accuracy of dynamic contour tonometry, Goldmann applanation tonometry, and Tono-Pen XL in edematous corneas. METHODS: Experimental study included 20 freshly enucleated porcine eyes. Epithelium was debrided, and eyes were divided in four groups. Groups were immersed in 35%, 40%, 50%, and 60% glycerin solutions for 3 hours. Subsequently, globes were mounted in a special holder, and their intraocular pressure was hydrostatically adjusted. Intraocular pressure was measured by means of dynamic contour tonometry, Goldmann applanation tonometry, and Tono-Pen XL while adjusting true intraocular pressure to 17, 33, and 50 mm Hg. Ultrasound pachymetry was performed. RESULTS: Mean corneal thickness was 914.5 ± 33.3 µm (730-1015 µm). In true intraocular pressure of 33 mm Hg, Goldmann applanation tonometry and dynamic contour tonometry significantly underestimated true intraocular pressure (mean Goldmann applanation tonometry: 14.7 ± 4.8 mm Hg, p < 0.001, mean dynamic contour tonometry: 21.6 ± 6.8, p < 0.001). Tono-Pen XL also underestimated, but difference was not statistically significant (Tono-Pen XL: 27.9 ± 9.7, p = 0.064). In true intraocular pressure of 50 mm Hg, all three methods significantly underestimated (Goldmann applanation tonometry: 17.6 ± 5.3 mm Hg, p < 0.001, dynamic contour tonometry: 26.8 ± 6.3 mm Hg, p < 0.001, Tono-Pen XL: 35.6 ± 8.4 mm Hg, p < 0.001). The error in measured intraocular pressure for each method (true minus measured intraocular pressure) was significantly correlated to true intraocular pressure (p < 0.001). The intraocular pressure measurements of each eye taken under true intraocular pressure of 17 and 33 mm Hg with the three methods were correlated to each other. Measurements taken under intraocular pressure of 50 mmHg were not correlated to each other. Corneal thickness was not correlated to intraocular pressure measurement. CONCLUSION: Goldmann applanation tonometry, dynamic contour tonometry, and Tono-Pen XL underestimate intraocular pressure when measured under edematous conditions. Tono-Pen XL showed better accuracy, especially in lower true intraocular pressure. The measurement error increases when true intraocular pressure increases in all three methods.

Long-term Comparison of Combined t-PTK and CXL (Cretan Protocol) Versus CXL With Mechanical Epithelial Debridement for Keratoconus.

PURPOSE: To compare the long-term outcomes of corneal cross-linking (CXL) for the treatment of keratoconus using two different techniques for epithelial removal: transepithelial phototherapeutic keratectomy (t-PTK) and mechanical epithelial debridement. METHODS: In this prospective, comparative, interventional case series, 26 patients (30 eyes) with progressive keratoconus underwent CXL treatment. Fifteen eyes (13 patients) underwent epithelial removal with t-PTK (Cretan protocol) and 15 eyes (13 patients) underwent mechanical epithelial debridement (Dresden protocol) during CXL. Visual, refractive, and keratometric outcomes were evaluated preoperatively and at 1, 2, 3, and 4 years postoperatively. RESULTS: No intraoperative or postoperative complications were observed in any of the patients. In the Cretan protocol group, mean uncorrected (UDVA) and corrected (CDVA) visual acuity improved from 0.99 ± 0.42 and 0.33 ± 0.28 logMAR preoperatively to 0.75 ± 0.32 (P = .018) and 0.21 ± 0.16 (P = .024) logMAR at 4 years postoperatively, respectively. In the Dresden protocol group, mean UDVA improved from 0.83 ± 0.47 logMAR preoperatively to 0.63 ± 0.40 logMAR (P = .033) at 4 years postoperatively, whereas mean CDVA did not demonstrate a statistically significant improvement postoperatively (P > .05). In the Cretan protocol group, mean corneal astigmatism improved from -6.19 ± 4.54 diopters (D) preoperatively to -4.68 ± 3.10 D (P = .041) at last follow-up, whereas in the Dresden protocol group there was no statistically significant difference postoperatively (P > .05). CONCLUSIONS: Epithelial removal with t-PTK during CXL (Cretan protocol) resulted in better visual, refractive, and keratometric outcomes compared with mechanical epithelial debridement over a long-term follow-up. [J Refract Surg. 2019;35(10):650-655.].

Combined transepithelial phototherapeutic keratectomy and conventional photorefractive keratectomy followed simultaneously by corneal crosslinking for keratoconus: Cretan protocol plus.

PURPOSE: To evaluate the visual, refractive, and topographic outcomes after combined transepithelial phototherapeutic keratectomy (PTK) and conventional photorefractive keratectomy (PRK) followed simultaneously by corneal crosslinking (CXL) for keratoconus. SETTING: Vardinoyiannion Eye Institute of Crete, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece. DESIGN: Prospective case series. METHODS: Patients with progressive keratoconus had simultaneous conventional PRK followed by CXL; the corneal epithelium was removed using transepithelial PTK (Cretan protocol plus). The visual, refractive, and topographic outcomes and the endothelial cell density (ECD) were evaluated preoperatively and 1, 3, 6, and 12 months postoperatively. RESULTS: Forty-three patients (55 eyes) were enrolled. The mean uncorrected and corrected distance visual acuities improved significantly from 0.98 ± 0.63 (SD) logarithm of minimum angle of resolution (logMAR) and 0.20 ±â€¯0.23 logMAR preoperatively to 0.39 ±â€¯0.35 logMAR (P < .001) and 0.08 ±â€¯0.16 logMAR (P < .001) 12 months postoperatively, respectively. The mean spherical equivalent improved significantly from -4.67 ±â€¯4.00 diopters (D) preoperatively to -2.24 ±â€¯2.81 D (P < .001) at 12 months. The mean steep keratometry (K) and flat keratometry readings decreased significantly from 50.30 ±â€¯5.00 D and 45.62 ±â€¯3.10 D preoperatively to 46.27 ±â€¯3.90 D (P < .001) and 43.46 ±â€¯3.00 D (P < .001) 12 months postoperatively, respectively. No ECD alterations were observed throughout the follow-up (P > .05). CONCLUSION: Combined transepithelial PTK and conventional PRK followed simultaneously by CXL was effective in corneal stabilization and vision improvement in keratoconic patients.

A Comparison of Refraction Defects in Childhood Measured Using Plusoptix S09, 2WIN Photorefractometer, Benchtop Autorefractometer, and Cycloplegic Retinoscopy.

PURPOSE: To compare Plusoptix (Gmbh, Nuremberg, Germany), 2WIN (Adaptica, Padua, Italy), the benchtop refractometer (Auto-Kerato-Refractometer KR-8900; Topcon Co, Tokyo, Japan), and retinoscopy with regard to the consistencies. MATERIALS AND METHODS: In our prospective study, 200 eyes of 100 patients were included. We analyzed the demographics and characteristics of the patients, the percentage of patients from whom measurements could not be obtained, the measurements from both patients' eyes of pupil diameter, spherical, cylindrical, axis, and spherical equivalence. RESULTS: The mean age ± SD was 7.8±4.5 years (range, 1-18 years). Pupil diameter measurements were found to be consistent (Cronbach's alpha value >0.8). The sphere and spherical equivalence measurements for both eyes were found to be consistent with each other in all apparatus (Cronbach's alpha value >0.8). However, consistency was found to be lower in cylindrical values and the Jackson cross-cylinder measurements at 0° and 45° axis were found to be inconsistent with each other (Cronbach's alpha value <0.8). CONCLUSIONS: While consistency was observed in all methods in terms of sphere and spherical equivalence, consistency dropped in cylindrical values and no consistency was observed in axis values. It is important to take this point into consideration, especially in axis measurements.

A new endocapsular open ring for prevention of anterior and posterior capsule opacification.

PURPOSE: The aim of this study is to demonstrate the functionality of a new design of a thick endocapsular open ring for prevention of anterior capsule opacification (ACO) and posterior capsule opacification (PCO). SETTING: The Institute of Vision and Optics, University of Crete and University Hospital of Heraklion, Crete, Greece. DESIGN: Prospective, interventional pilot study. METHODS: Fifteen patients (17 eyes) underwent cataract surgery with phacoemulsification. During surgery, a thick endocapsular open ring (peripheral capsule reconstructor) was inserted into the capsular bag, prior to intraocular lens (IOL) implantation. Six different models of IOL were implanted. Postoperatively, the degree of ACO and PCO was evaluated and described as none, mild, moderate, or severe. RESULTS: The mean follow-up period was 30±8.06 months (range: 12-36 months). At the last follow-up, mild PCO was observed in only three eyes and mild ACO in three patients. The centration of IOLs was good in all but one eye, which had a tilted IOL. CONCLUSION: The results of this pilot study suggest that the implantation of a new design of thick endocapsular open ring is feasible and may contribute to the prevention of PCO and ACO after cataract surgery.

Combined Cataract and Refractive Corneal Inlay Implantation Surgery: Comparison of Three Techniques.

PURPOSE: To compare clinical outcomes of three different techniques of combined cataract and Presbia Flexivue Microlens refractive corneal inlay (Presbia Coöperatief U.A., Amsterdam, Netherlands) implantation surgery for presbyopia compensation over a 12-month follow-up. METHODS: In this comparative pilot study, 15 patients with bilateral cataract were allocated to one of three groups with a different combination of surgical steps (cataract surgery, intrastromal pocket creation, and inlay implantation). In the three-step group, the intracorneal pocket was created in the non-dominant eye, bilateral cataract surgery was performed 3 months later, and the intracorneal inlay was inserted 3 months after that. In the two-step at 3 days group, bilateral cataract surgery was performed 3 days after pocket creation and inlay implantation in the non-dominant eye. In the two-step at 3 months group, the pocket creation and the inlay implantation were performed in the non-dominant eye 3 months after bilateral cataract surgery. Visual, refractive, and contrast sensitivity outcomes were evaluated and compared between the three groups. RESULTS: Twelve months after the inlay implantation, mean monocular uncorrected distance visual acuity was 20/32 in the three-step group, 20/32 in the two-step at 3 days group, and 20/25 in the two-step at 3 months group. Achieved mean monocular uncorrected near visual acuity was similar in the three groups (20/25). The visual and refractive outcomes did not show significant differences between groups. Contrast sensitivity was similar between groups under mesopic and photopic conditions. No intraoperative or postoperative complications were observed. CONCLUSIONS: Clinical outcomes of three different techniques of combined cataract surgery and refractive corneal inlay implantation had no apparent differences between them. The corneal inlay provided excellent near vision acuity, with high patient satisfaction and a high spectacle independence rate after cataract surgery. [J Refract Surg. 2016;32(5):318-325.].

EX-PRESS® Implant Position and Function: Comparative Evaluation with Ultrasound Biomicroscopy and Optical Coherence Tomography.

PURPOSE: This study evaluated the feasibility of anterior segment optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM) for the imaging of EX-PRESS(®) implant. MATERIALS AND METHODS: This nonrandomized comparative case series was performed at the Department of Ophthalmology of the University Hospital of Heraklion, Crete, Greece. The Ellex Eye Cubed (40 MHz) UBM and the Zeiss Visante OCT systems were used. The filtering bleb morphology (BL), aqueous outflow (AS), and tube position (TB) were evaluated by two independent observers using a quality scale of 1 (worst) to 4 (best). Data were also collected on corneal and iris clearance from the tip of the tube (CC and IC, respectively). Data from both the devices were statistically analyzed. P < 0.05 was considered as statistically significant. RESULTS: Ten eyes of 10 patients (6 males) with EX-PRESS(®) implant were examined. TB, AS, and BL scores using UBM were 2.40 ± 0.39, 3.45 ± 0.72, and 2.45 ± 0.64, respectively. TB, AS, and BL scores for OCT were 3.35 ± 0.41, 1.55 ± 0.43, and 2.55 ± 0.55, respectively. AS was significantly higher with UBM whereas the opposite was true for TB. Differences in BL between OCT and UBM were not statistically significant (P > 0.05). CONCLUSION: Imaging of the EX-PRESS(®) implant is feasible with both UBM and OCT. Both modalities allow visualization of the position of the implant tube in relation to the iris or cornea and delineate the internal structure of the filtering bleb.

PresbyLASIK approach for the correction of presbyopia.

PURPOSE OF REVIEW: The aim of this review is to offer a comprehensive overview of the different PresbyLASIK approaches, which have been published in peer-reviewed journals. RECENT FINDINGS: Comprehensive search was conducted in scopus using keywords presbyLASIK, presbyopia, LASIK, corneal multifocality. We reviewed binocular uncorrected and corrected distance and near visual acuity, and loss of lines of best corrected visual acuity, for presbyopic patients among three different basic treatment modalities. SUMMARY: Additional trials and standards for reporting results for presbyopic approaches are necessary. Careful patient selection and counseling is imperative in all PresbyLASIK treatments.

High resolution MR eye protocol optimization: Comparison between 3D-CISS, 3D-PSIF and 3D-VIBE sequences.

PURPOSE: The purpose of this study was to compare selected MRI pulse sequences and to evaluate their utility for depicting specific anatomic regions in the eye. METHODS: A High-Resolution (HR) 0.08 × 0.08 × 0.60 mm(3) MRI protocol was developed on a 1.5-T clinical system and applied in the left eye of an albino rabbit, utilizing a small field of view surface coil. The comprehensive MRI protocol consisted of two 3D (T2/T1)w sequences (3D-PSIF and 3D-CISS), and one 3D T1w sequence (3D-VIBE). The T1w 3D-VIBE sequence was acquired, before and after intravenous injection of 0.2 mmol/kgr gadolinium-DTPA. Signal-to-Noise Ratios (SNR) and Contrast-to-Noise Ratios (CNR) amongst specific eye anatomical areas were calculated for each sequence. The presence of artifacts was rated subjectively utilizing a 5 point scale. RESULTS: 3D-PSIF and 3D-CISS provide better delineation and visualization of the eye as compared with 3D-VIBE sequences. 3D-CISS images present the highest SNR and revealed better discrimination of the ocular surrounding tissues; its basic drawback though is related to ghost artifacts appearing in the anterior chamber and resulting in the lowest image quality. In post-contrast imaging, the T1w 3D-VIBE sequence provided the best overall image quality. Moreover, 3D (T2/T1)w sequences can provide good anatomic depiction of the eye segments. Agreement between the two independent readers was good. CONCLUSIONS: Optimization of a comprehensive MR eye imaging protocol is achieved. A higher SNR, a better spatial resolution and a reduction of the total scan time were obtained, thus making clinical MRI systems more reliable in eye imaging.

Manometric measurement of the outflow facility in the living human eye and its dependence on intraocular pressure.

PURPOSE: The intraocular pressure (IOP) is determined by a dynamic equilibrium between the production and outflow of the aqueous humour. The relationship between IOP and the outflow rate through the conventional and unconventional pathway is quantified by the outflow facility coefficient (C). The purpose of this study is to employ a direct (manometric) tonographic technique and determine C as well as its inverse, resistance (R), as a function of IOP in the living human eye. METHODS: Nineteen cataract patients were enrolled in the study. An intraoperative manometric device was used to measure IOP. After cannulation of the anterior chamber, the IOP was increased by infusion of controlled amounts of saline solution. At 40 mmHg, the infusion stopped, and a pressure sensor recorded the IOP. The measured pressure-volume relationship was considered in order to convert pressure changes to corresponding ocular volume changes. An appropriate mathematical model was applied to calculate C and (its inverse), R. RESULTS: The average C was 0.0672 ± 0.0296 µl/min/mmHg at 40 mmHg and 0.2652 ± 0.1164 µl/min/mmHg at 20 mmHg. There was a strong dependence of coefficient C on IOP in all subjects (p < 0.001). The corresponding values for R were 17.9 ± 11.17 min mmHg/µl at 40 mmHg and 4.51 ± 2.69 min mmHg/µl at 20 mmHg. CONCLUSION: This study provides measurement of outflow facility and its dependence with pressure in healthy living human eyes. This relation is shown to be non-linear, using a direct manometric method.

Ocular higher-order aberrations in a school children population.

PURPOSE: The primary objective of the study was to explore the statistics of ocular higher-order aberrations in a population of primary and secondary school children. METHODS: A sample of 557 children aged 10-15 years were selected from two primary and two secondary schools in Heraklion, Greece. Children were classified by age in three subgroups: group I (10.7±0.5 years), group II (12.4±0.5 years) and group III (14.5±0.5 years). Ocular aberrations were measured using a wavefront aberrometer (COAS, AMO Wavefront Sciences, USA) at mesopic light levels (illuminance at cornea was 4lux). Wavefront analysis was achieved for a 5mm pupil. Statistical analysis was carried out for the right eye only. RESULTS: The average coefficient of most high-order aberrations did not differ from zero with the exception of vertical (0.076µm) and horizontal (0.018µm) coma, oblique trefoil (-0.055µm) and spherical aberration (0.018µm). The most prominent change between the three groups was observed for the spherical aberration, which increased from 0.007µm (SE 0.005) in group I to 0.011µm (SE 0.004) in group II and 0.030µm (SE 0.004) in group III. Significant differences were also found for the oblique astigmatism and the third-order coma aberrations. CONCLUSIONS: Differences in the low levels of ocular spherical aberration in young children possibly reflect differences in lenticular spherical aberration and relate to the gradient refractive index of the lens. The evaluation of spherical aberration at certain stages of eye growth may help to better understand the underlying mechanisms of myopia development.

Femtosecond Laser-Assisted Intra-Corneal Drug Delivery.

PURPOSE: To present a case of fungal keratitis that was successfully treated with direct intrastromal medication delivery through a corneal incision created with the femtosecond laser. METHODS: A 71-year-old female patient with recurrent episodes of an unresponsive, deep stromal keratitis for six months' duration, resistant to various therapeutic approaches, was referred to our institute. The 150 kHz Intralase iFS laser (Abbott Medical Optics Inc., Santa Ana, CA) was used to create a corneal pocket in an attempt to permit drug delivery directly into the corneal abscess. RESULTS: Five days after the intrastromal injections, the clinical condition was improved. Two years after the procedure, the cornea is stable and free of any clinical signs or symptoms of recurrence. CONCLUSIONS: In this case report, an alternative application of femtosecond laser technology is presented, performing intrastromal drug delivery through a corneal incision for the treatment of fungal keratitis.

Prospective comparison of low-fluence photodynamic therapy combined with intravitreal bevacizumab versus bevacizumab monotherapy for choroidal neovascularization in age-related macular degeneration.

PURPOSE: To evaluate combination treatment with reduced-fluence photodynamic therapy (RDPDT) with Verteporfin and intravitreal bevacizumab, compared to bevacizumab alone, for choroidal neovascularization (CNV) in age-related macular degeneration. METHODS: This was a prospective, randomized comparative study comprising 95 patients with CNV. 49 patients received RDPDT (25 J/cm(2)) followed by intravitreal bevacizumab 1.25 mg one hour later, while 46 received intravitreal bevacizumab alone. Patients were followed for 12 months at four-week intervals with visual acuity (VA) assessment and Optical Coherence Tomography (OCT) of the macula. Bevacizumab re-injections were performed as needed. RESULTS: On average, patients were re-injected 4.45 times in the combination group and 6.96 times in the bavacizumab group (p < 0.001). At 12 months, VA improved by 8.64 letters in the bevacizumab group and by 8.37 letters in the combination group (p = 0.922). CONCLUSION: Adding a reduced-fluence PDT arm in combination with bevacizumab offers similar results to those of intravitreal bevacizumab alone with significantly reduced number of injection repetitions.

Anterior segment applications of in vivo confocal microscopy.

PURPOSE: To review the current literature on in vivo confocal microscopy anterior segment applications (cornea, conjunctiva, and glaucoma) and discuss its advantages in different pathological conditions. METHODS: Review of selected relevant literature on in vivo confocal microscopy and its different applications. RESULTS: In vivo confocal microscopy can be used to visualize most layers of the cornea and conjunctiva, providing excellent resolution. In the past, it was mainly utilized as a research tool; lately there seems to be an increasing interest for clinical applications; confocal microscopy aids the diagnosis and follow-up of many anterior segment disorders, such as corneal dystrophies, corneal and conjunctival inflammatory and neoplastic diseases, glaucoma patients, and assessment of surgical procedures. CONCLUSION: In vivo confocal microscopy is an important addition to the ophthalmic diagnostic tools with several anterior segment applications. Its clinical applications are being continuously explored and are quickly expanding to cover many new pathological aspects.

Long-term follow-up of corneal collagen cross-linking for keratoconus--the Cretan study.

PURPOSE: The aim of this study was to present the long-term results of corneal collagen cross-linking (CXL) in patients with keratoconus. METHODS: In this prospective, interventional case series, patients with progressive keratoconus underwent CXL treatment according to the Dresden protocol. Visual, refractive, and topographic outcomes along with endothelial cell density were evaluated preoperatively and at 1, 2, 3, 4, and 5 years postoperatively. RESULTS: Twenty-one patients (25 eyes) were enrolled. The mean follow-up was 43.7 ± 12.2 (range, 24-60) months. Logarithm of the minimum angle of resolution (logMAR) mean uncorrected visual acuity and the mean best spectacle-corrected visual acuity improved significantly from 0.92 ± 0.54 and 0.29 ± 0.21 preoperatively to 0.63 ± 0.41 (P = 0.010) and 0.18 ± 0.18 (P = 0.011), respectively, at the last follow-up. Mean steep and mean flat keratometry readings reduced significantly from 52.53 ± 6.95 diopters (D) and 48.11 ± 5.98 D preoperatively to 49.10 ± 4.50 D (P < 0.001) and 45.58 ± 3.81 D (P = 0.001), respectively, at the last follow-up. The mean endothelial cell density was 2708 ± 302 cells per square millimeter preoperatively and did not change significantly (P > 0.05) at any postoperative interval (2593 ± 258 cells/mm at the last follow-up; P = 0.149). CONCLUSIONS: CXL seems to be effective and safe in halting progression of keratoconus over a long-term follow-up period up to 5 years postoperatively.

Long-term results of combined transepithelial phototherapeutic keratectomy and corneal collagen crosslinking for keratoconus: Cretan protocol.

PURPOSE: To present the long-term results of combined transepithelial phototherapeutic keratectomy (PTK) and corneal collagen crosslinking (CXL) for keratoconus. SETTING: Vardinoyiannion Eye Institute of Crete, University of Crete, Heraklion, Crete, Greece. DESIGN: Prospective case series. METHODS: Patients with progressive keratoconus had combined transepithelial PTK and CXL (Cretan protocol). Visual and refractive outcomes and the endothelial cell density (ECD) were evaluated preoperatively and postoperatively. RESULTS: Twenty patients (23 eyes) were enrolled; postoperatively 23 eyes were evaluated at 1 and 2 years, 11 at 3 years, and 7 at 4 years. The mean follow-up was 33.83 months±10.82 (SD) (range 24 to 56 months). No intraoperative or postoperative complications occurred. The mean uncorrected distance visual acuity improved significantly from 0.99±0.57 logMAR preoperatively to 0.61±0.36 logMAR at the last follow-up (P<.001) and the mean corrected distance visual acuity, from 0.27±0.24 logMAR to 0.17±0.14 logMAR (P=.018), respectively. The mean steep and mean flat keratometry readings decreased significantly from 53.39±7.14 diopters (D) and 47.17±4.87 D, respectively, preoperatively to 49.99±4.36 D (P<.001) and 45.47±2.95 D (P=.002), respectively, at the last follow-up. The mean corneal astigmatism improved significantly from -6.27±4.19 D preoperatively to -4.52±2.80 D (P<.001) at the last follow-up. No significant ECD alterations occurred (P>.05). CONCLUSION: Combined transepithelial PTK and CXL was effective and safe in keratoconic patients over a long-term follow-up. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Evaluation of iridociliary and lenticular elasticity using shear-wave elastography in rabbit eyes.

INTRODUCTION: A previous study has employed shear-wave ultrasound elastographic imaging to assess corneal rigidity in an ex-vivo porcine eye model. This study employs the same modality in vivo in a rabbit eye model in order to assess lens, ciliary body and total ocular rigidity changes following the instillation of atropine and pilocarpine. METHODS: Ten non-pigmented female rabbits were examined. Measurements of the lens, ciliary body and total ocular rigidity as well as lens thickness and anterior chamber depth were taken with the Aixplorer system (SuperSonic Imagine, Aix-en-Provence, France) with the SuperLinear™ SL 15-4 transducer in both eyes at baseline as well as after pilocarpine and atropine instillation. The IOP was also measured with the TonoPen tonometer. RESULTS: Changes in rigidity in the examined areas following atropine instillation were statistically not significant. Ciliary body rigidity was significantly increased whereas lens and total ocular rigidity were significantly reduced following pilocarpine instillation. The decrease in lens rigidity following pilocarpine was significantly associated with the respective increase in ciliary body rigidity. CONCLUSIONS: Shear-wave ultrasound elastography can detect in vivo rigidity changes in the anterior segment of the rabbit eye model and may potentially be applied in human eyes, providing useful clinical information on conditions in which rigidity changes play an important role, such as glaucoma, pseudoexfoliation syndrome or presbyopia.