Current perspectives in Bietti crystalline dystrophy.

Bietti crystalline dystrophy (BCD) is a rare-inherited disease caused by mutations in the CYP4V2 gene and characterized by the presence of multiple shimmering yellow-white deposits in the posterior pole of the retina in association with atrophy of the retinal pigment epithelium (RPE) and chorioretinal atrophy. The additional presence of glittering dots located at the corneal limbus is also a frequent finding. The CYP4V2 protein belongs to the cytochrome P450 subfamily 4 and is mainly expressed in the retina and the RPE and less expressed in the cornea. The disease has its metabolic origin in the diminished transformation of fatty acid substrates into n-3 polyunsaturated fatty acids due to a dysregulation of the lipid metabolism. In this review, we provide updated insights on clinical and molecular characteristics of BCD including underlying mechanisms of BCD, genetic diagnosis, progress in the identification of causative genetic and epigenetic factors, available techniques of exploration and development of novel therapies. This information will help clinicians to improve accuracy of BCD diagnosis, providing the patient reliable information regarding prognosis and clinical prediction of the disease course.

[Vascular morphological and microdensity changes of corneal neovascularization induced by topical bevacizumab and sunitinib in an animal model]. / Cambios en la morfología y la microdensidad neovascular corneal inducidos tras la administración tópica de bevacizumab y sunitinib en un modelo animal.

OBJECTIVE: To evaluate the effects of topical bevacizumab and topical sunitinib on vascular microdensity and morphology of corneal neovascularization (NV). METHODS: A total of 33 rabbits were distributed into 3 groups: group 1 (control; n=11): saline; group 2 (n=11): bevacizumab 5mg/ml; and group 3 (n=11): sunitinib 0.5mg/ml. A corneal NV model was used, based on sutures in the right eye of each rabbit. Each treatment was administered topically 3 times daily for 14 days. Corneas were then processed for the study of vascular microdensity (6 eyes) and vascular morphology analysis (5 eyes) using enzymatic staining histological techniques RESULTS: The vascular response in group 3 was limited to small-sized tree formations with various vascular axes compared with the extensive, lush and directional corneal NV of group 1 and 2. In the histological sections near the limb, there were no differences in vascular microdensity studies between the three groups. However, the mean sectional area of vessels (MSAV) in group 3 was 41.88% lower than in group 1 and 19.19% lower than in group 2. In distal sections, there were no differences between groups 1 and 2. However, group 3 was characterized by absence of vessels. CONCLUSIONS: Bevacizumab produced no changes in the morphology of the vessels or the vascular microdensity. Sunitinib reduced the size of the new vessels and induced changes in the vascular tree.

[Orbital penetrating wound by a bull horn]. / Herida penetrante orbitaria por asta de toro.

INTRODUCTION: Bull horn injuries are severe lesions with a high risk of bacterial contamination, and are common in countries where people are fond of bullfighting and related spectacles. CASE REPORT: A 19-year-old man was referred with a penetrating wound in the superior left eyelid produced by a bull horn and resulting in a fracture of the orbital roof and a fat hernia. Prophylactic antibiotics and tetanus toxoid were administered and surgical reconstruction of the wound performed. Orbital cellulitis did develop, but this responded to systemic antibiotic therapy within a few days. DISCUSSION: Successful treatment of this type of lesion requires early diagnosis, meticulous surgical exploration and appropriate use of prophylactic antibiotics and tetanus toxoid.

Actinomyces neuii subspecies anitratus chronic endophthalmitis after cataract surgery.

PURPOSE: To report a case of unusual chronic endophthalmitis by Actinomyces neuii subspecies anitratus. METHODS: A 75-year-old man underwent uneventful phacoemulsification with implantation of a foldable posterior chamber intraocular lens in his right eye. Four weeks after surgery, a chronic post-operative endophthalmitis characterized by anterior chamber and vitreous cellular debris developed in this eye. Cultures were positive, and A neuii subspecies anitratus was identified by polymerase chain reaction and subsequent rRNA sequence analysis. Immediate treatment included intravitreal and intensive topical antibiotics along with oral ciprofloxacin. RESULTS: The condition improved rapidly, and 6 months after surgery the patient was asymptomatic, the best spectacle-corrected visual acuity was 20/22, and the anterior chamber was quiet. CONCLUSIONS: A neuii subspecies anitratus should be considered in the differential diagnosis of chronic endophthalmitis after cataract surgery. Polymerase chain reaction and subsequent RNA typing were useful in detecting the causative organism, and intravitreal antibiotics were successful.

Effects of lamellar keratotomy on postkeratoplasty astigmatism.

AIM: To determine the changes in postkeratoplasty astigmatism induced by lamellar keratotomy. METHODS: A prospective, non-randomised comparative trial of patients undergoing a hinged lamellar corneal flap for treatment of significant astigmatism after penetrating keratoplasty. Uncorrected visual acuity, best corrected visual acuity, refraction, and corneal topography were assessed at 1 and 3 months after the lamellar keratotomy. RESULTS: 17 eyes in 16 patients (13 M, 3F) were included in the study (mean age 48.2 years; range 20-86 years). Six of 17 eyes (35.3%) changed more than 1 dioptre (D) in spherical equivalent by 3 months. Nine of 17 eyes (52.9%) changed more than 1 D in sphere by 3 months. 12 of 17 eyes (70.6%) changed more than 1 D in refractive cylinder. Seven patients of 15 (46.7%) changed more than 1 D in corneal power as measured topographically. Five of 17 eyes (29.4%) changed in refractive cylinder axis more than 15 degrees and this was similar to the change measured topographically of four of 15 eyes (26.7%). Vector analysis showed 60% of eyes had a surgically induced astigmatism (SIA) vector of more than 1 D, including a net corneal astigmatism decrease of more than 1 D in four eyes and increase of more than 1 D in two eyes at 3 months after surgery. Complications of the lamellar keratotomy included two partial buttonholes and one partial wound dehiscence. CONCLUSIONS: The creation of a lamellar flap alone can have significant effects on the astigmatism following penetrating keratoplasty. LASIK for correction of postkeratoplasty astigmatism may be more accurately performed as a two stage procedure rather than a single stage, after the corneal effects of the lamellar keratotomy have stabilised.

Ultrasound biomicroscopy of ZSAL-4 anterior chamber phakic intraocular lens for high myopia.

PURPOSE: To evaluate the intraocular location and anatomic relationship to other structures of the ZSAL-4 angle-supported anterior chamber phakic intraocular lens (IOL) for high myopia using ultrasound biomicroscopy (UBM). SETTING: Clínica de Nuestra Señora de la Concepción, Fundación Jiménez Díaz, and Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Madrid, Spain. METHODS: Eight phakic myopic eyes corrected by ZSAL-4 angle-supported anterior chamber phakic IOLs were examined by UBM. The distance between the corneal endothelium and the IOL at the central and peripheral cornea and between the phakic IOL and the iris was measured. RESULTS: The mean distance between the central cornea and the IOL was 2361.37 microm +/- 109.62 (SD); between the edge of the IOL optic and the endothelium, 1646.24 +/- 27.06 microm; and between the IOL and the iris, 354.46 +/- 41.61 microm. The IOL footplates appeared to be correctly positioned in the anterior chamber angle in all eyes. CONCLUSION: The space between the IOL and the endothelium was greater in eyes with the ZSAL-4 angle-supported phakic IOL than in eyes with other angle-supported phakic IOLs. The possibility of intermittent contact between the IOL edge and the midperipheral cornea plays a minor role in the mechanism of endothelial damage with this lens model.

Haze after laser in situ keratomileusis in eyes with previous photorefractive keratectomy.

In cases with previous photorefractive keratectomy (PRK), there is a risk of developing severe haze after laser in situ keratomileusis (LASIK). We report 3 patients (4 eyes) who developed severe haze after LASIK treatment for residual myopia following PRK. Both PRK and LASIK procedures were performed using the VISX 20/20 excimer laser. We report the grade of haze, amount of regression, and visual acuity after the patients were treated with topical steroids. In 2 eyes, the uncorrected visual acuity was 1.0 after 1 year with grade I haze. In the other 2 eyes, there was a residual refractive error, and the best spectacle-corrected visual acuity was 0.7 with grade II haze.

Therapeutic lamellar keratoplasty with an automated microkeratome.

Penetrating keratoplasty (PKP) is the predominant form of corneal transplantation because both manual and automated lamellar keratoplasty are technically difficult and lead to complications such as irregularities and scarring. A microkeratome for laser in situ keratomileusis can be used to overcome these disadvantages. We describe a technique of lamellar keratoplasty performed with an automated microkeratome to treat corneal opacities in the anterior third of the cornea. This easy, accurate technique leads to good visual results and represents a good alternative to PKP in treating anterior corneal opacities.

Laser in situ keratomileusis for treatment of residual myopia after photorefractive keratectomy.

PURPOSE: To evaluate the results of laser in situ keratomileusis after photorefractive keratectomy. METHODS: Eighty eyes of 80 patients with residual myopia after photorefractive keratectomy were reoperated with laser in situ keratomileusis. The study was retrospective. Laser in situ keratomileusis was performed using the automated corneal shaper microkeratome and Chiron Technolas 217-C d1 excimer laser. Data measured after laser in situ keratomileusis included uncorrected visual acuity, best-corrected visual acuity, refraction, haze, pachymetry, and keratometry. The follow-up was at least 12 +/- 1.6 months (range, 12 to 15 months). RESULTS: After laser in situ keratomileusis the mean spherical equivalent was -0.24 diopters +/- 0.78. (range, -3 to +1.5) at 12 months, and the mean uncorrected visual acuity was 0.76 diopters +/- 0.24 (range, 0.1 to 1). Sixty-five eyes (81.3%) had various degrees of haze after laser in situ keratomileusis. One eye (1.2%) lost 2 lines of best-corrected visual acuity. CONCLUSIONS: Laser in situ keratomileusis enhancement may be a good alternative to correct residual myopia and astigmatism after primary photorefractive keratectomy. Corneal haze is a common problem in these eyes, and the treatment after laser in situ keratomileusis enhancement should be the same as the treatment after primary photorefractive keratectomy.

[Circular flap rhexis: a refinement technique for LASIK re-treatment]. / Flaprhexis circular: una técnica minuciosa para el retratamiento tras LASIK.

PURPOSE: To describe a new approach to re-treatment after Laser in situ keratomileusis (LASIK) by means of lifting the corneal flap in order to decrease the epithelial damage and its related complications, such as epithelial ingrowth and flap melting, which are more frequent after LASIK re-treatment than after primary LASIK. MATERIAL AND METHODS: The new technique, called circular flap rhexis, is based on a careful flap edge identification, linear epithelial tear for minimizing epithelial irregularities and defects, and a delicate flap replacement to promote a strong adhesion between the flap edge and the stromal bed. The LASIK re-treatment with this flap rhexis technique was performed in 43 eyes at 3 or 6 months after the primary LASIK. After a 12 month follow-up, the epithelial ingrowth and flap melting rates were recorded. RESULTS: Epithelial growth was found in 9.3% of the cases (4 out of 43 eyes) and flap melting in 2.3% of the cases (1 out of 43) at 12 months after LASIK re-treatment by circular flap rhexis. These disorders were always peripheral and did not affect visual acuity or corneal astigmatism. CONCLUSION: LASIK re-treatment using circular flap rhexis is an effective technique to decrease the epithelium related complications after LASIK re-treatment.

Choroidal neovascularization in myopic eyes after laser-assisted in situ keratomileusis.

PURPOSE: To analyze the appearance and characteristics of choroidal neovascularization (CNV) in patients with high myopia corrected by laser-assisted in situ keratomileusis (LASIK). PATIENTS AND METHODS: The authors studied CNV in 2955 consecutive eyes (1632 patients) that underwent LASIK for the correction of myopia (from -6 to -27.5 diopters). Follow-up was 34.2+/-11.3 months. RESULTS: Choroidal neovascularization occurred in three eyes (0.10%) and in one eye previous CNV was reactivated (three women, one man). The time interval between refractive surgery and CNV was 13+/-9.5 months (range, 4-26 months). Mean best-corrected visual acuity (BCVA) after LASIK and before CNV development was 20/57 (range, 20/100-20/29). After the appearance of CNV, mean BCVA was 20/606 (range, 20/2000-20/80). Differences between BCVA before and after CNV were statistically significant (P = 0.04, paired Student's t-test). The CNV was treated in two cases by argon laser photocoagulation and in two cases by surgical excision of CNV by vitrectomy. The final mean BCVA was 20/277 (range, 20/800-20/50). Differences between BCVA after LASIK and after CNV treatment were statistically significant (P = 0.04, paired Student's t-test). CONCLUSIONS: Laser-assisted in situ keratomileusis as a correcting procedure for myopia was followed by low appearance of CNV. The appearance and treatment of CNV was followed by a significant decrease of BCVA.

Laser in situ keratomileusis to correct residual myopia after cataract surgery.

PURPOSE: To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) for correcting residual myopia after cataract surgery with intraocular lens implantation. METHODS: Twenty-two eyes of 22 patients underwent LASIK for the correction of residual myopia after cataract surgery. LASIK was carried out using the Chiron Automated Corneal Shaper and the NIDEK EC-5000 excimer laser. In all eyes, the follow-up was 12 months. RESULTS: Before LASIK, 1 eye (4.5%) had an uncorrected visual acuity of 0.5 or better; 12 months after LASIK, 10 eyes (45.4%) achieved this level of visual acuity and 0 eyes achieved 1.00 or better. Before LASIK, mean refraction was -2.90 +/- 1.80 D; 12 months after LASIK it decreased significantly to 0.40 +/- 0.60 D (P < .01). In 18 eyes (81.8%) at 12 months after LASIK, spherical equivalent refraction was within +/-1.00 D of emmetropia; 11 eyes (50%) were within 0.50 D. No vision-threatening complications occurred. CONCLUSION: LASIK with the Automated Corneal Shaper and Nidek EC-5000 excimer laser was an effective, predictable, stable, and safe procedure for correcting residual myopia after cataract surgery. No intraocular lens or cataract incision related complications occurred when LASIK was performed at least 3 months after phacoemulsification.

Corneal sensitivity and some properties of the tear film after laser in situ keratomileusis.

PURPOSE: To investigate central corneal sensitivity, lipid layer structure of the precorneal tear film, and tear volume after laser in situ keratomileusis (LASIK). METHODS: Central corneal sensitivity was measured using the Non-Contact Corneal Aesthesiometer. The aesthesiometer was mounted on a slit lamp and an airpulse of controlled pressure was directed onto the cornea. When central corneal sensitivity was reduced, a higher air pulse pressure was required to stimulate the cornea. The final central corneal sensitivity threshold measured was recorded in millibars. Tear lipid layer structure was assessed by optical interferometry and classified according to appearance using the Keeler Tearscope. Tear volume was measured using the phenol red cotton thread test. Subjects were recruited from a group of patients after LASIK who had experienced no complications (n=22). The average postoperative time was 14 weeks and measurements were taken on one eye. In bilateral cases, measurements were recorded from the right eye only. Average attempted correction was -6.30 D (range, -2 to -11 D). Age-matched controls were later recruited for central corneal sensitivity threshold (n=24). A second group of age-matched controls were recruited for tear volume and lipid layer structure (n=24). RESULTS: The median (range) was 1.1 mbars (0.2 to 4.3 mbars) after LASIK and 0.58 mbars (0.20 to 1.3 mbars) in the controls; the difference was statistically significant (P = .043). The lipid layer of the tear film tended to be thinner in eyes after LASIK compared with controls (P = .032). The mean (+/- SD) tear volume was 16.9 +/- 8.3 mm after LASIK and 19.8 +/- 7.1 mm in controls. This difference was not statistically significant (P = .492). CONCLUSION: At 14 weeks postoperatively, central corneal sensitivity was below normal levels and the tear lipid layer was thinner. The poorer quality lipid layer may predispose to symptoms of dry eye after LASIK.

Laser in situ keratomileusis flap margin: wound healing and complications imaged by in vivo confocal microscopy.

PURPOSE: To examine the healing response of laser in situ keratomileusis flap margin in vivo. METHODS: Forty-three eyes of 43 patients who had undergone myopic (n = 39) or hyperopic (n = 4) laser in situ keratomileusis were examined once after surgery. The flap margin was imaged by in vivo confocal microscopy at various depths, and the wound healing response, flap alignment, and complications were evaluated. Ten eyes were examined on day 3 postoperatively, 13 eyes at 1 to 2 weeks, 10 eyes at 1 to 2 months, five eyes at 3 months, and five eyes at 6 months or later. RESULTS: At 3 days after laser in situ keratomileusis, the surface epithelium and basal epithelium appeared normal. Keratocyte activation was strongest at 1 to 2 weeks and 1 to 2 months, and an increased amount of haze was observed correspondingly. Intrastromal epithelial cells forming a plug could occasionally be perceived in the wound gape. Wound constriction was completed in most cases by 3 to 6 months or later. Good alignment was observed in 12 of 43 flaps (27.9%) and moderate and poor alignment in 17 of 43 flaps (39.5%) and 13 of 43 flaps (30.2%), respectively. Poor alignment was not associated with lamellar epithelial ingrowth. Epithelial ingrowth was associated with dense haze at the interface. Diffuse lamellar keratitis was imaged in two corneas after hyperopic laser in situ keratomileusis. CONCLUSIONS: The laser in situ keratomileusis incision wound at the flap margin appears to heal after the sequence observed in incisional wounds in nonhuman primates. Complications, such as lamellar epithelial in growth and diffuse lamellar keratitis, were often observed, particularly after hyperopic laser in situ keratomileusis.

Postoperative inflammation, microbial complications, and wound healing following laser in situ keratomileusis.

Although the biology of corneal wound healing is only partly understood, healing after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) differs in many respects, and the mechanisms appear to be differently controlled. There is less of an inflammatory and healing response after LASIK, but a longer period of sensory denervation. The cellular, molecular, and neural regulatory phenomena associated with postoperative inflammation and wound healing are likely to be involved in the adverse effects after LASIK, such as flap melt, epithelial ingrowth, and regression. Interface opacities in the early postoperative period include diffuse lamellar keratitis (DLK), microbial keratitis, epithelial cells, and interface opacities. Diffuse lamellar keratitis (sands of the Sahara syndrome) describes an apparently noninfectious diffuse interface inflammation after lamellar corneal surgery probably caused by an allergic or a toxic inflammatory reaction. Noninfectious keratitis must be distinguished from microbial keratitis to avoid aggressive management and treatment with antimicrobial drugs. Microbial keratitis is a serious complication after LASIK, but a good visual outcome can be achieved following prompt and appropriate treatment.

Surgical correction of severe myopia with an angle-supported phakic intraocular lens.

PURPOSE: To evaluate the effectiveness, predictability, and safety of a fourth-generation angle-supported anterior chamber phakic intraocular lens (IOL) in patients with severe myopia. SETTING: Refractive Surgery and Cornea Unit, Alicante Institute of Ophthalmology, Miguel Hernández University School of Medicine, Alicante, Spain. METHODS: In this prospective study, 23 eyes (16 patients) with a mean preoperative myopia of -19.56 diopters (D) +/- 1.76 (SD) (range -16.75 to -23.25 D) were implanted with the ZSAL-4 phakic IOL. Basic examinations were performed before and after surgery in all patients. Eighteen eyes were also studied by clinical specular microscopy, and the endothelium was analyzed for cell density, coefficient of variation in cell size, and hexagonality. The location of the IOL in the anterior chamber was evaluated in 10 eyes by A-scan biometry. To evaluate haptic geometry, a theoretical mechanical model was used. The follow-up was 24 months in all patients. RESULTS: Uncorrected visual acuity was 20/40 or better in 13 eyes (56.0%) 12 months after surgery and in 14 eyes (60.8%) at 24 months. Best spectacle-corrected visual acuity improved 0.19 at 12 and 24 months (0.1 = 1 line) from preoperative values. The efficacy index was 1.12 at 24 months and the safety index, 1.45. The mean postoperative spherical equivalent was -0.65 +/- 0.65 D at 24 months. The postoperative spherical equivalent was within +/-1.00 D of emmetropia in 19 eyes (82.6%) at 12 and 24 months. The mean endothelial cell loss was 3.50% at 12 months and 4.18% at 24 months. The coefficient of variation in cell size decreased from 0.34 before surgery to 0.28 at 24 months after surgery. The IOL was located 0.79 +/- 0.24 mm in front of the crystalline lens. Postoperative complications included night halos in 6 eyes (26.1%) at 12 and 24 months and pupil ovalization in 4 eyes (17.4%). Intraocular lens rotation was observed in 10 eyes (43.5%) at 24 months. Two eyes (8. 7%) developed a slight inflammatory response during the first 6 months. Our mechanical model predicted that the compression forces against the angle structures were greater at the first footplate than at the second. CONCLUSIONS: Implantation of the ZSAL-4 IOL in the anterior chamber of phakic eyes was effective and predictable in correcting severe myopia. However, the ZSAL-4 did not prevent pupil ovalization, IOL rotation, or low-grade postoperative uveitis. Improvements in haptic design following our mechanical model could decrease these haptic-related complications.

A model to explain the difference between changes in refraction and central ocular surface power after laser in situ keratomileusis.

PURPOSE: After refractive surgery, changes in central ocular surface power are usually less than actual changes in refraction. The aim of this paper was to examine the theoretical changes in the radius of the epithelial-stromal interface and corneal stromal refractive index which could take place to account for some of the empirical findings. METHODS: The parameters of an aspheric human eye model featuring gradient index optics was modified using data from a clinical study evaluating effects of laser in situ keratomileusis (LASIK) for correction of moderate to high myopia. Computations were performed to determine: 1) theoretical postoperative radius of the epithelial-stromal interface and hence distribution of epithelial thickness, and 2) refractive index of the stroma when the epithelium was of fixed uniform thickness. RESULTS: Within the central 2-mm diameter refractive zone of the cornea after LASIK for myopia, either of two factors could account for the difference between changes in central ocular surface power and the actual change in ocular refraction: 1) a steepening of the epithelial-stromal interface resulting from a 400% centrifugal increase in epithelial thickness, or 2) a reduction in stromal refractive index from an average of 1.376 to 1.364. CONCLUSION: The difference between the observed changes in refraction and central ocular surface power could be explained by reduction in stromal refractive index and this could be secondary to a 6.5% increase in water content of the stroma during the postoperative period. The epithelial-stromal interface after LASIK is unlikely to steepen by the extent predicted by our model. This surface is not the source of the difference between the change in refraction and change in central ocular surface power.