[The effect of keratoconus-associated refractive errors on the results of tomographic methods of studying the posterior structures of the eye]. / Vliyanie opticheskikh narushenii pri keratokonuse na rezul'taty tomograficheskikh metodov issledovaniya struktur zadnego segmenta glaza.

PURPOSE: The study assesses the potential influence of refractive errors in keratoconus (KC) on the results of tomographic methods of studying the structures of the posterior eye segment. MATERIAL AND METHODS: The study included 30 patients with bilateral stabilized KC of stages I-IV in classification by M. Amsler. Spherical and cylindrical components of refractions were determined using automatic refractometry, keratometry measurements - based on scanning keratotopography with Scheimpflug analyzer. Aberrometry was performed to evaluate corneal wave front according to the following parameters: root mean square for lower order aberrations (RMS LOA), root mean square for higher order aberrations (RMS HOA), vertical trefoil, vertical coma, horizontal coma and spherical aberrations. Optical coherence tomography (OCT) and laser confocal scanning ophthalmoscopy (HRT 3) data was used in morphometric analysis of the optic nerve head and peripapillary retina. The following morphometric parameters were analyzed: optic nerve head (ONH) area, optic disc cup area, optic disc cup volume, ratio of optic disc cup area to ONH area, neuroretinal rim area, neuroretinal rim volume, peripapillary retinal nerve fiber layer (RNFL) thickness. All studies were performed first without correction, and 30 minutes after installing customized scleral hard contact lenses (SHCL). RESULTS: Compensation of the refractive errors characteristic for KC was achieved as expected with contact correction. OCT revealed a general trend for reduction in the area and volume of the optic disc cupping, ratio of area to volume of the optic disc cupping, as well as an increase in other parameters. As such, with correction the values for area and volume of the neuroretinal rim according to OCT were 2.2 and 13%, HRT 3 - 18 and 51.6%; comparable increase in mean RNFL thickness - 2.8 and 28.5%, respectively (p<0.001). According to HRT 3 data, the area and volume of optic disc cupping statistically significantly decreased (by 21 and 28%, respectively), while OCT showed statistically significant decrease only in cupping area (by 5.7%). The ratio of cupping to ONH area decreased by 6.6 and 23% relative to the initial data obtained with OCT and HRT 3, respectively. Significant decrease in ONH area amid SHCL correction was observed only with HRT 3. The revealed changes in morphometric parameters were analyzed using the fundamental principles of physiological optics. Changes in interference pattern and, consequently, morphometric parameters of structures of the eye fundus in KC are of multifactorial nature, and are mostly associated with refractive and wave artefacts occurring when the rays pass through the irregular corneal surface and cannot be optically compensated by the device. The use of SHCL as means for making the optic system relatively regular can significantly decrease the artefacts in morphometric measurements. CONCLUSION: The results obtained in this study demonstrate the practicality of tomographic examination in KC with contact correction. The optimal choice is custom-fit SHCL, which along with proper correction of refractive errors also ensures stable position of the lens on the cornea. In standard examination specialists should take into account the «false¼ decrease in parameters of the peripapillary retinal nerve fiber layer and increase in ONH cupping.

Association of retinitis pigmentosa and advanced keratoconus in siblings.

Objective. The aim of the article was to present the rare association of retinitis pigmentosa and bilateral keratoconus in two brothers, one of whom developed corneal hydrops bilaterally, within a short period of time. Methods. A 29-year-old man presented to our service with corneal hydrops in the right eye, complaining of ocular pain and photophobia. He had a history of retinitis pigmentosa, having been diagnosed as an infant. He also had a younger brother carrying the same diagnosis. Slit lamp examination revealed bilateral keratoconus with corneal hydrops in the right eye, posterior subcapsular cataract, macular atrophy and the characteristic retinal signs of retinitis pigmentosa. The patient's brother was also examined, with the same findings being noted, apart from the corneal hydrops. We documented the changes using a slit lamp biomicroscope, a fundus camera, a corneal topography, Anterior Segment Optical Coherence Tomography and visual field testing. Right hydrops regressed in one month after hyperosmolar 5% sodium chloride treatment. However, 4 weeks later, the patient presented with the same corneal findings in the left eye. The same treatment was prescribed for the left eye. Results. Corneal hydrops regressed in both eyes with remaining paracentral corneal scars. However, no other treatment for keratoconus was suitable in the case of this patient. Discussion: Retinitis pigmentosa is currently not amenable to any form of treatment, from vitamin supplementation, medical therapy, gene transfer-based therapy, stem cell-based therapy to retinal implantation. However, molecular genetics may someday provide new therapeutic prospects, that could modify the course of RP. Conclusions. The association of retinitis pigmentosa with keratoconus is a fairly rare finding, worth taking into consideration. Also, presentation with keratoconus in such an advanced state is uncommon and, in our case, it was presumably due to the patient's reduced visual function since childhood, secondary to retinitis pigmentosa, that has prevented him from perceiving any visual modifications caused by keratoconus.

Iridocorneal endothelial syndrome in a patient with keratoconus - a case report.

BACKGROUND: To describe a case of a rare association of bilateral keratoconus and unilateral essential iris atrophy and to conduct a literature review of the current strategies of treatment of the corneal disease and glaucoma in patients with Iridocorneal Endothelial Syndrome (ICE). CASE PRESENTATION: We report a rare association of bilateral keratoconus and unilateral essential iris atrophy in a 38-year-old man. Diagnosis of bilateral keratoconus was confirmed by corneal topography. Slit-lamp examination showed extensive iris atrophy with corectopia and policoria in one eye. Corneal specular microscopy revealed an abnormal endothelium morphology in the same eye with extensive peripheral anterior synechiae and closure of the drainage angle at gonioscopy. Intraocular pressure was 26 mmHg, despite maximal topical therapy. Optic disc examination showed severe glaucomatous cupping. Surgery by glaucoma drainage device implantation was performed. CONCLUSION: Essential iris atrophy is a rare clinical variant of ICE syndrome characterized by profound anatomical alterations of the anterior segment associated with corneal edema and secondary glaucoma. In these patients, selective keratoplasties have replaced penetrating keratoplasty to treat corneal decompensation and glaucoma drainage devices are preferred to conventional trabeculectomy for the treatment of secondary glaucoma.

Performing corneal crosslinking under local anaesthesia in patients with Down syndrome.

PURPOSE: To report on the ability to perform corneal crosslinking (CXL) under local anaesthesia for the treatment of keratoconus in patients with Down syndrome. METHODS: Nine eyes of seven patients with both keratoconus and Down syndrome were scheduled for an epithelium-off CXL procedure under local anaesthesia. Exclusion criteria were a corneal thickness under 400 µm and the presence of corneal scars. A standardized clinical decision tool was used to estimate patient cooperation and the likelihood for a successful procedure under local rather than general anaesthesia. RESULTS: In seven eyes, the CXL was completed successfully. The treatment was aborted in two eyes due to insufficient corneal thickness (<400 µm) prior to ultraviolet-A irradiation, even after employing hypoosmolar riboflavin. No adverse events occurred post-operatively, except for one case of delayed epithelial healing (23 days). CONCLUSIONS: With a proper patient selection, CXL under local anaesthesia can be achieved in patients with Down syndrome.

Combined application of prophylactic corneal cross-linking and laser in-situ keratomileusis - a review of literature.

Laser in-situ keratomileusis (LASIK) is safe and effective laser refractive procedures in treating refractive errors. However, regression of treatment and iatrogenic keratectasia remain to be a major concern, especially in treating thin cornea with high ametropia. Collagen cross-linking (CXL) is an effective method in stopping keratoconus progression through increasing the biomechanical strength of the cornea. Adjuvant cross-linking to refractive procedures can theoretically help prevent regression and reduce the risk of keratectasia development by increasing the mechanical stability of cornea. During the procedure, riboflavin is directly applied to the corneal stroma, thereby reducing the need of de-epithelialization as in the conventional protocol for keratoconus. Currently, there is still no consensus regarding the indication of CXL during refractive procedure, nor any standardized treatment protocol. This article aims to summarize the current evidence regarding the use of adjuvant CXL in LASIK.

Acute bilateral corneal hydrops caused by high temperature and high moisture in the Finnish sauna. A clinical and histological case report of a patient with keratoconus.

A 44-year-old healthy male with bilateral keratoconus developed acute hydrops of both his corneas with an interval of 3 years. On both occasions he had bathed in a hot, humid Finnish sauna the preceding evening. Penetrating keratoplasty had to be performed in the acute stage in both instances, as medical therapy brought no improvement. The contributory role of hot, moist air to the development of acute hydrops is discussed. Histopathological examination of the corneal buttons revealed clear-cut breaks in Descemet's membrane with marked posterior stromal oedema.

Treatment of contact lenses with papain. Increase in wearing time in keratoconic patients with papillary conjunctivitis.

In 15 Keratoconic patients with papillary conjunctivitis associated with wearing rigid polymethylmethacrylate contact lenses, the cleaning of the lenses with enzymatic contact lens cleaner (papain) increased lens wearing time in nine and diminished the symptoms of mucus and itching in 12. In 13 control, lens-wearing keratoconic subjects with papillary conjunctivitis, three had a decrease, four had an increase, and six had no change in lens wearing time and one had a diminution of symptoms. Use of the enzymatic contact lens cleaner did not, however, influence the biomicroscopic appearance of the papillary conjunctivitis. The inclusion of the enzymatic contact lens cleaner in the cleaning regimen offered an adequate improvement in wearing time and tolerance for three of four patients that previously suffered a reduction in wearing time that compromised or precluded their vocational responsibilities.