Correlation between ocular biometric parameters and corneal endothelium in a sample of young Egyptian adults.

Background: To evaluate the normative values of corneal endothelial cell parameters within a group of healthy young Egyptian adults using specular microscopy and to examine any correlations between endothelial parameters and refractive or biometric parameters. Methods: In this cross-sectional study, specular microscopy was used to study the right eyes of 150 healthy young volunteers and evaluated endothelial cell parameters, including cellular density, hexagonality (HEX), and coefficient of variation (CV) at 15 different points on the back corneal surface, which were later grouped into the central zone and either four quadrants or three annular zones. The same eyes underwent refractive and biometric assessments. Results: Hundred fifty healthy adults were examined, and the age ranged from 20 to 30 years, with a median of 23 (interquartile range, 21‒27) years. The mean (standard deviation) of central cell density was 2902.7 (270.7) cells/mm2. The superior paracentral area had the lowest mean density (2895.8 cells/mm2), but the highest mean HEX (67.7%), while the inferior peripheral area had the highest mean density (3100.5 cells/ mm2) but the lowest mean HEX (64%). The difference in cell density among the three annular zones was not statistically significant (P = 0.365). However, HEX and CV in the central and paracentral zones differed statistically significantly from those of the peripheral zone (P < 0.001 and P = 0.014, respectively). Weak but non-significant correlations were detected between endothelial cell density and all measured refractive and biometric parameters. Conclusions: The findings of this study provided useful normative biometric and specular data in a specific age group and a specific population, and could be useful in planning intraocular surgery in young Egyptian adults. However, future longitudinal studies with a larger sample could refine more endothelial cell parameter specifications over time.

Central retinal artery resistive index and optical coherence tomography in assessment of glaucoma progression.

AIM: To assess the relation between central retinal artery (CRA) resistive index (RI) and retinal nerve fiber thickness measured by optical coherence tomography (OCT) in assessment of disease progress in cases of open angle glaucoma. METHODS: Twenty-three patients with diagnosed open angle glaucoma were included in this study. They were examined by colored duplex ultrasonography of CRA with estimation of RI of CRA and ophthalmic artery (OA) with estimation of CRA/OA RI ratio as well as OCT measurement of the average retinal nerve fiber layer (RNFL) thickness in order to assess the disease progress. RESULTS: There was strong inverse relation between the increased RI in CRA as well as the increased CRA/OA RI ratio and the decrease in average RNFL thickness in cases of open angle glaucoma. CONCLUSION: Assessment of CRA RI can indirectly assess the vascular changes associated with glaucoma and can assess the degree of retinal atrophy helping in evaluating prognosis thus guiding the choice of treatment.

Acute posterior multifocal placoid pigment epitheliopathy: role of TNF blocker in severe cases.

PURPOSE: The aim of this study was to describe cases with severe acute posterior multifocal placoid pigment epitheliopathy treated with tumor necrosis factor (TNF) blocker [Remicade (infliximab)] as regards the improvement of visual acuity, contralateral affection, and prevention of recurrence. METHODS: We analyzed patients with severe acute posterior multifocal placoid pigment epitheliopathy confirmed by fluorescein fundus angiography as regards the demographic data (age, sex) and the most relevant clinical findings such as, visual acuity, retinal condition, association with other systemic diseases, and response to TNF blocker. RESULTS: Eight patients were included in this study, 5 (62.5%) of them had unilateral lesion and 3 (37.5%) had bilateral lesions. The mean age of the patients was 29.5 ± 8.5 years (range, 19 to 42 years). Of them, 3 (37.5%) were women and 5 (62.5%) were men. All patients received TNF blocker (Remicade) in 4 doses (infusion of 100 mg), 4 weeks apart. The mean follow-up period was 23.6 ± 9.9 months (range, 8-36 months). During this period, no recurrence occurred with control of the associated systemic disease. There was a statistically significant improvement of the visual acuity from 0.49 ± 0.36 to 0.69 ± 0.21 (P < 0.05). Among patients with unilateral lesion, three developed contralateral affection. Adverse effects from Remicade did not occur. CONCLUSION: The TNF blocker can be used in patients with severe acute posterior multifocal placoid pigment epitheliopathy with no recurrence rate. However, it does not prevent the contralateral affection. Another prospective study with a control group and longer follow-up time is needed to confirm these results and to evaluate the effect of TNF blocker on final visual acuity.

Effect of corneal collagen crosslinking on femtosecond laser channel creation for intrastromal corneal ring segment implantation in keratoconus.

PURPOSE: To evaluate the effect of collagen crosslinking (CXL) on femtosecond laser channel creation for intrastromal corneal ring segments (ICRS) in keratoconic eyes. SETTING: Magrabi Eye Hospital, Cairo, Egypt. DESIGN: Comparative case series. METHODS: Eyes with grade II or III keratoconus were treated by CXL. After 6 months, channel creation was performed using an IntraLase FS-60 femtosecond laser. The eyes were randomly divided into 3 groups. The default femtosecond machine power setting was 1.5 mJ in Group 1, 1.6 mJ in Group 2, and 1.7 mJ in Group 3. A control group included virgin noncrosslinked keratoconic eyes in which the default power setting was 1.5 mJ. The degree of difficulty of ICRS insertion was judged subjectively. The degree of postoperative corneal haze was recorded. RESULTS: Fifteen eyes of 11 patients had CXL. Each group, including the control, comprised 5 eyes. After CXL, intracorneal channel creation using the 1.5 mJ default femtosecond power setting was incomplete and mechanical dissection was required to complete the channel. When the power setting was increased to 1.6 mJ or 1.7 mJ, channel creation could be completed; however, this increased the corneal reaction (haze) postoperatively. The corneal haze resolved in all eyes within 6 weeks, and there were no further complications. CONCLUSIONS: Femtosecond laser channel creation can be performed after CXL; however, the laser power must be modified. Results show channel dissection and ICRS implantation should be performed before or concurrent with CXL. FINANCIAL DISCLOSURE: The author has no financial or proprietary interest in any material or method mentioned.

Sequential versus concurrent KERARINGS insertion and corneal collagen cross-linking for keratoconus.

PURPOSE: To evaluate the safety and efficacy of combined intracorneal ring segments (KERARINGS) insertion and corneal collagen cross-linking (CXL) performed in one session or two sessions and to present the refractive outcomes. SETTING: Magrabi Eye Hospital, Cairo, Egypt. METHODS: This prospective comparative study included 16 eyes of 10 patients with progressive mild to moderate keratoconus that were randomly divided into two groups. Group 1 included nine eyes that underwent KERARINGS insertion followed by CXL 6 montsh later; group 2 included seven eyes that underwent the two procedures at the same day. In both groups channel creation was performed using the femtosecond laser (Intralase FS 60). RESULTS: There was statistically significant improvement in both groups' uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), with significant reduction in refractive error and keratometric values (p<0.05). There was no statistically significant difference between both groups regarding the changes in UDVA, CDVA and refractive error (p>0.05). However, group 2 revealed more statistically significant reduction of keratometric values on topographical examination (p=0.046). The stromal haze that developed in both groups was more marked and persistent in group 2 than in group 1. CONCLUSION: Combined KERARINGS insertion and CXL can be performed safely in one or two sessions. However, the same-session procedure appears to be more effective regarding the improvement in the corneal shape.

Riboflavin-Ultraviolet A Corneal Cross-linking for Keratoconus.

PURPOSE: To evaluate the safety, efficacy of riboflavin-ultraviolet A irradiation (UVA) corneal cross-linking and present refractive changes induced by the treatment in cases of keratoconus. MATERIALS AND METHODS: The study includes 15 eyes of 9 patients with keratoconus with an average keratometric (K) reading less than 54 D and minimal corneal thickness greater than 420 microns. The corneal epithelium was removed manually within the central 8.5 mm diameter area and the cornea was soaked with riboflavin eye drops (0.1% in 20% dextran tau-500) for 30 minutes followed by exposure to UVA radiation (365 nm, 3 mW/cm(2)) for 30 minutes. During the follow-up period, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, slit lamp examination and topographic changes were recorded at the first week, first month, 3 and 6 months. RESULTS: There was statistically significant improvement of UCVA from a preoperative mean of 0.11 +/- 0.07 (range 0.05-0.3) to a postoperative mean of 0.15 +/- 0.06 (range 0.1-0.3) (P < 0.05). None of the eyes lost lines of preoperative UCVA but 1 eye lost 1 line of preoperative BSCVA. The preoperative mean K of 49.97 +/- 2.81 D (range 47.20-51.75) changed to 48.34 +/- 2.64 D (range 45.75-50.40). This decrease in K readings was statistically significant (P < 0.05). All eyes developed minimal faint stromal haze that cleared in 14 eyes within 1 month. In only 1 eye, this resulted in a very faint corneal scar. Other sight threatening complications were not encountered in this series. Progression of the original disease was not seen in any of the treated eyes within 6 months of follow-up. CONCLUSION: Riboflavin-UVA corneal cross-linking is a safe and promising method for keratoconus. Larger studies with longer follow up are recommended.

Sequential Intacs and Verisyse phakic intraocular lens for refractive improvement in keratoconic eyes.

PURPOSE: To evaluate the safety, efficacy, and stability of sequential Intacs (Addition Technology, Inc.) insertion and Verisyse phakic intraocular lens (pIOL) (AMO) implantation in selected cases of keratoconus. SETTING: Magrabi Eye Hospital, Cairo, Egypt. METHODS: Prospective data were collected from 8 eyes of 6 keratoconus patients with contact lens intolerance, clear corneas, a maximum K-value less than 60.0 diopters (D), and minimum corneal thickness greater than 400 mum. Two 0.45 mm Intacs were inserted through a 1.8 mm radial incision created at 70% of the corneal depth opposite the cone apex. The 2 rings were pushed to meet and embrace the cone apex. Refraction 6 months after Intacs insertion showed residual myopia greater than 6.0 D and residual astigmatism not more than 2.0 D. Thus, a phakic Verisyse IOL was implanted horizontally in the anterior chamber through a 6.5 mm superior clear corneal incision, which was closed with 3, 10-0 nylon sutures after a peripheral iridectomy was created. The uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction, and topographic profiles were taken 1 week and 1, 3, 6, 9, 12, 18, and 24 months after the second surgery. RESULTS: All eyes achieved UCVA of 20/40 or better. The final spherical error ranged from -1.75 to +1.00 D and the cylindrical error, from 1.25 to 2.50 D. No eye lost lines of preoperative BCVA. These results were relatively stable throughout the follow-up period. CONCLUSIONS: Sequential Intacs and a Verisyse pIOL implantation was safe, stable, and effective in selected cases of keratoconus. It is a reversible surgery that is less invasive than penetrating keratoplasty (PKP). It can avoid or postpone the need for PKP, although it is not an alternative.