Unilateral Malignant Glaucoma Postbilateral Implantable Collamer Lens: Effect of Miotics.

An implantable collamer lens® (ICL) V4c model (STAAR Surgical, Monrovia, CA, USA) was placed in the eye of a 31-year-old male patient with high myopia followed by the development of malignant glaucoma. After failing medical treatment for 5 days, a noncomplicated pars plana vitrectomy and anterior hyaloidectomy succeeded in breaking the aqueous misdirection. Sixteen months later, intraoperative miotics were purposefully withheld from the ICL surgery in the fellow eye and malignant glaucoma did not develop. Even though the patient's visual acuity postoperatively was 20/20, OU, a single small atrophic iris patch in the affected eye resulted in slightly more halos and glare in mesopic conditions as compared to the fellow eye. Earlier surgical intervention may have prevented iris ischemia and iridocorneal touch with its subsequent iris atrophy and resulted in an even more favorable visual outcome. Withholding intraoperative miotics during ICL surgery appeared to be beneficial in this case.

Inducing fibrogenesis and new interfibrillary bonds in post-laser in situ keratomileusis keratectasia.

Flap creation weakens the cornea and is a risk factor for keratectasia after laser in situ keratomileusis (LASIK). We describe a new technique to halt the progression of keratectasia by mechanically reintegrating the flap into the residual stroma. Deep stromal vertical puncturing is performed in the 4.0 to 9.0 mm paracentral corneal zone at a depth of 350 to 420 µm. The puncturing is applied in circumferential rows using a 25-gauge needle or a diamond blade, with denser puncturing at the level of the cone. In 5 eyes with worsening post-LASIK keratectasia, improved uncorrected and corrected visual acuities, corneal flattening, and a hyperopic shift were observed. There was no progression of keratectasia on serial topographies. New collagen fibrogenesis was documented by optical coherence tomography. The technique seems to be promising to halt the progression of post-LASIK keratectasia. More clinical data and longer follow-up are needed for validation.

Mathematical analysis of corneal remodelling after intracorneal ring surgery in keratoconus.

AIM: To represent mathematically the intersection between the ectatic corneal geometry and the plane of intracorneal ring implants (ICRS) in order to determine the corneal response to ICRS surgery in keratoconus (KC). Thereafter, to present the concept and early results of a newly derived topography-guided nomogram for ICRS surgery for the treatment of keratectasia. METHODS: The corneal rings plane intersection was modelled to a conic section. Ring effect was the result of: the ring size, position (steep vs flat), location (distance from the geometric centre of the cornea), and the discrepancy between the ring's curvature and the tunnel's curvature. Femtosecond laser was used to create the tunnels and the incision sites were chosen according to the nomogram in order to place the thickest ring in the steepest portion of the cornea regardless of the astigmatism axis of refraction. RESULTS: The conic section had a more prolate shape in the steep area of the cornea than in the flat area, depending on the corneal sagittal curvature. Equal ring size had more flattening effect in the steep area than in the flat area. Thick segment should be implanted under the steep portion of the cornea regardless of the cylinder axis of refraction. Single segment in the steep area was sufficient in early and moderate cases of KC. The new nomogram provided more topographic regularity with significant reduction of astigmatism and better improvement in uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) than the conventional nomogram. CONCLUSION: The newly derived nomogram can produce better results than the conventional nomogram. Moreover, based on this concept, a new nomogram can be integrated into the femtosecond laser software to create topography-guided, customized, elliptical tunnels with modified focal asphericity that allows for customized focal flattening of the irregularly steepened ectatic cornea.

Safety and Efficacy of Sequential Intracorneal Ring Segment Implantation and Cross-linking in Pediatric Keratoconus.

PURPOSE: To evaluate the safety and visual outcome of intracorneal ring segment (ICRS) implantation followed by cross-linking in pediatric keratoconus patients. DESIGN: Retrospective interventional case series. METHODS: This retrospective study included pediatric patients (aged ≤14 years) with keratoconus and poor corrected distance visual acuity (CDVA) that underwent ICRS implantation and cross-linking (CXL). ICRS were inserted under topical anesthesia after creating a corneal tunnel with a femtosecond laser. Cross-linking was performed 1 month subsequently. Records were reviewed and data collected preoperatively and at 6 months, 1 year, 2 years, and 4 years postoperatively. RESULTS: Twelve patients (17 eyes; 10 male, 2 female) aged 9-14 years (mean age 12.3 years) received ICRS implantation followed by CXL. Follow-up times ranged from 6 months to 4 years after surgery. At the 6-month follow-up all eyes were evaluated; at the 1-year, 2-year, and 4-year follow-up 11, 10, and 7 eyes were evaluated, respectively. At the 6-month follow-up, mean CDVA in comparison to preoperative levels improved significantly (P = .001) from 0.30 ± 0.19 logMAR to 0.12 ± 0.1 logMAR; mean uncorrected distance visual acuity (UDVA) also improved significantly from 0.90 ± 0.50 logMAR to 0.43 ± 0.31 logMAR. A significant decrease in both keratometry readings and spherical equivalent (from -4.0 to -1.56 diopters) was also noted after ICRS insertion. At the 1-year, 2-year, and 4-year follow-up refractive values remained relatively stable in comparison to the 6-month follow-up, except for a minor but significant improvement in cylinder and, at 4 years, in UDVA. All patients tolerated the surgery well and no intraoperative or postoperative complications were reported, except for 1 ring segment that had to be removed after 2 years owing to vascularization and corneal thinning. CONCLUSION: ICRS implantation is a safe and effective procedure for visual rehabilitation in children with keratoconus and poor CDVA.

Pediatric Keratoconus in a Tertiary Referral Center: Incidence, Presentation, Risk Factors, and Treatment.

PURPOSE: To report the incidence, clinical presentation, risk factors, and treatment outcome of pediatric keratoconus in a tertiary referral eye hospital in Beirut, Lebanon. METHODS: In this retrospective study, the authors evaluated all patients with keratoconus 14 years or younger newly diagnosed at the Beirut Eye Specialist Hospital, Beirut, Lebanon, between January 2010 and December 2014. The incidence of pediatric keratoconus among all pediatric patients and among patients with keratoconus of all ages was assessed. Patients with pediatric keratoconus were evaluated for keratoconus stage, initial presentation, uncorrected distance visual acuity, corrected distance visual acuity (CDVA), corneal topography, and pachymetry. Patients were classified according to different treatment regimen groups and different follow-up visits were evaluated. RESULTS: During 5 years, 16,808 patients were examined, of whom 2,972 were 14 years or younger. A total of 541 patients were diagnosed as having keratoconus; of those, 16 were 14 years or younger at the time of diagnosis. Hence, the incidence of keratoconus was 0.53% among pediatric patients and 3.78% among adult patients (> 14 years). Initial presentation was during routine checkup (1 of 16) for allergic conjunctivitis (3 of 16), reduced vision (10 of 16), and corneal hydrops (mimicking keratitis) (2 of 16). Except for 2 patients lost to follow-up, all eyes received corneal cross-linking treatment and 16 eyes received additional intracorneal ring segment implantation. CONCLUSIONS: The incidence of pediatric keratoconus indicates that increased awareness for keratoconus among children is needed, mainly in cases of family history of keratoconus, ocular allergy/pruritus, poor CDVA, corneal hydrops, and/or high astigmatism. [J Refract Surg. 2016;32(8):534-541.].

Rate of corneal collagen crosslinking redo in private practice: risk factors and safety.

Objective. To report the rate of progression of keratectasia after primary crosslinking (CXL) and evaluate the safety and efficiency of CXL redo. Materials and Methods. We conducted a retrospective analysis of the patients who underwent CXL between 2010 and 2013 at the Beirut Eye Specialist Hospital, Lebanon. Progression of keratectasia was based on the presence of an increase in maximum keratometry of 1.00 D, a change in the map difference between two consecutive topographies of 1.00 D, a deterioration of visual acuity, or any change in the refraction. Primary and redo CXL were done using the same protocol. Results. Among the 221 eyes of 130 patients who underwent CXL, 7 eyes (3.17%) of five patients met the criteria of progression. All patients reported a history of allergic conjunctivitis and eye rubbing and progressed within 9 to 48 months. No complications were noted and all patients were stable 1 year after CXL redo. Conclusion. Allergic conjunctivitis and eye rubbing were the only risk factors associated with keratoconus progression after CXL. A close followup is thus mandatory, even years after the procedure. CXL redo seems to be a safe and efficient technique to halt the progression after a primary CXL.

Acute corneal hydrops mimicking infectious keratitis as initial presentation of keratoconus in a 10-year-old child.

Purpose. To report a case of acute hydrops in a 10-year-old child with advanced keratoconus. Case Presentation. A ten-year-old boy diagnosed as having right eye (RE) infectious keratitis, not responding to antimicrobial therapy, was referred to our hospital. The diagnosis of infectious keratitis was established one month prior to his presentation following an episode of acute corneal whitening, pain, and drop in visual acuity. Topical fortified antibiotics followed by topical antiviral therapy were used with no improvement. Slit lamp examination showed significant corneal protrusion with edema surrounding a rupture in Descemet's membrane in the RE. The diagnosis of acute corneal hydrops from advanced keratoconus was highly suspected and confirmed with corneal topography. Conclusion. Although a relatively rare disease at the age of 10 years, keratoconus can be rapidly progressive in the pediatric group. Keratoconus should always be considered in the differential diagnosis of progressive vision loss in this age group.

Spontaneous simultaneous bilateral malignant glaucoma of a patient with no antecedent history of medical or surgical eye diseases.

PURPOSE: Malignant glaucoma, or aqueous misdirection syndrome, is a condition characterized by sudden intraocular pressure (IOP) elevation, and it is usually unilateral and induced by ocular surgical intervention or by medical therapy. Here, we report a case of simultaneous bilateral malignant glaucoma in a young patient with no history of any ocular diseases. CASE REPORT: A case of a 24-year-old female with no apparent previous history of ocular medical or surgical conditions was referred to our hospital because of recent bilateral IOP elevation associated with a severe drop in vision and shallow anterior chamber with no posterior segment anomalies detected by ocular ultrasound in both eyes. Yttrium aluminum garnet (YAG) laser iridotomy dropped the IOP only temporarily and the patient received topical atropine treatment with combined trabeculectomy and anterior vitrectomy. RESULTS: In this case, the patient had a typical presentation of bilateral malignant glaucoma and her IOP dropped only temporarily following laser iridotomy to rise again shortly thereafter. Also, deepening of the anterior chamber and IOP decrease after topical atropine was very supportive of the diagnosis of malignant glaucoma. Successful management with trabeculectomy and limited vitrectomy also affirmed the diagnosis of malignant glaucoma. CONCLUSION: This is a very rare case of bilateral malignant glaucoma in a young adult without any prior eye conditions; only one similar case has been reported in the literature. We propose our own theory regarding this simultaneous occurrence of the pathology based on previously published studies about the presence of communication between the two eyes along the cerebrospinal fluid pathways.

Intraocular lens power calculation following LASIK: determination of the new effective index of refraction.

PURPOSE: To determine the new corneal effective index of refraction (rN) following LASIK to be used for accurate keratometry reading (K-reading). METHODS: A total of 332 eyes that underwent myopic LASIK were divided into two groups (group A [n = 137] and group B [n = 1951). In each group, patients were divided into four subgroups according to the amount of spherical equivalent refraction of myopic LASIK ablation (subgroup 1 [< -4.0 D], subgroup 2 [-4.0 to < -8.0 D], subgroup 3 [-8.0 to -12.0 D], and subgroup 4 [> -12.0 D]). In each subgroup of group A, K-reading was measured by the clinical history method and the new corneal effective index (rN) was determined using paraxial formula: (K-reading = (rN-1)/Ra), where Ra is the radius of curvature of the anterior corneal surface. In group B, the anterior radius of curvature of the cornea was determined by automated K-reading, and K-reading was measured in each subgroup using the new effective index in paraxial formula, clinical history method, and automated K-reading. RESULTS: In group A, the new effective index of refraction was 1.3355, 1.3286, 1.3237, and 1.3172 in the four subgroups, respectively. In group B, the mean K-reading measurements using rN in paraxial formula, clinical history method, and automated K-reading were: 40.33 +/- 1.68 D, 40.33 +/- 1.67 D, and 40.54 +/- 1.69 D, respectively, in subgroup 1; 37.96 +/- 1.26 D, 38.03 +/- 1.38 D, and 38.98 +/- 1.28 D, respectively, in subgroup 2; 35.77 +/- 1.75 D, 35.84 +/- 1.85 D, and 37.29 +/- 1.83 D, respectively, in subgroup 3; and 34.03 +/- 1.49 D, 34.15 +/- 1.84 D, and 36.21 +/- 1.59 D, respectively, in subgroup 4. In all subgroups of group B, the results of K-reading obtained using the new effective index of refraction were statistically similar to the results obtained by clinical history method (P > .05). Automated K-reading statistically overestimated the K-reading values in subgroups 2, 3, and 4 of group B (P < .001). CONCLUSIONS: The use of the new corneal effective index of refraction allows for an accurate derivation of K-reading from the anterior radius of curvature.

Intraocular pressure measurement after hyperopic and myopic LASIK.

PURPOSE: To assess the effects of hyperopic and myopic laser in situ keratomileusis (LASIK) on the intraocular pressure (IOP) measurement by Goldmann applanation tonometry. METHODS: Intraocular pressure was measured by Goldmann applanation tonometry pre- and postoperatively in 48 hyperopic eyes (26 patients) and 56 myopic eyes (28 patients). RESULTS: The mean preoperative spherical equivalent refraction was +3.97 +/- 2.48 diopters (D) in the hyperopic group and -6.73 +/- 4.79 D in the myopic group. Attempted correction was equivalent to preoperative refraction in each group. Mean preoperative IOP was 14.22 +/- 2.56 mmHg and 13.70 +/- 2.09 mmHg in the hyperopic and myopic groups, respectively. Following LASIK, the mean IOP was 11.85 +/- 2.52 mmHg and 11.38 +/- 3.08 mmHg in the hyperopic and myopic groups, respectively. CONCLUSIONS: The IOP measurement was significantly reduced (P < .001) by 2.37-2.25 mmHg and 2.32 +/- 2.89 mmHg following hyperopic and myopic LASIK, respectively.

Combined ICRS insertion and LASIK to maximize postoperative residual bed thickness in high myopia.

PURPOSE: To describe a new technique and early outcomes of combined intrastromal corneal ring segment (ICRS) insertion and laser in situ keratomileusis (LASIK) to treat patients with moderate to high myopia and thin corneas. SETTING: University-based academic practice, Boston, Massachusetts, USA. METHODS: Combined ICRS insertion and LASIK was performed in 2 stages: ICRS channel formation (stage I) followed by LASIK and ICRS insertion (stage II). RESULTS: Fifteen eyes of 11 patients with a mean preoperative spherical equivalent of -9.98 diopters (D) +/- 2.60 (SD) (range -7.13 to -16.25 D) and mean preoperative astigmatism of 1.11 +/- 0.75 D (range 0.00 to -3.00 D) were treated with combined ICRS insertion and LASIK. The mean central pachymetry was 526.13 +/- 35.69 microm (472 to 579 microm). The uncorrected visual acuity was 20/40 or better in 7 of 15 eyes (46.67%) at 1 month, 6 of 12 eyes (50.00%) at 3 months, 5 of 12 eyes (41.67%) at 6 months, and 6 of 12 eyes (50.00%) at 12 months. The best spectacle-corrected visual acuity was 20/40 or better at all times. Postoperative maps confirmed the absence of ectasia. The postoperative spherical equivalent was within +/-1.00 D of the intended refraction in 11 of 15 eyes (73.33%) at 1 month, 9 of 12 eyes at 3 and 6 months, and 8 of 12 eyes (66.67%) at 12 months. CONCLUSIONS: Results of combined ICRS insertion and LASIK in moderately to highly myopic patients with relatively thin corneas were good. Long-term studies are needed to determine whether this procedure will decrease the risk of LASIK-induced keratectasia in these patients.

New formula for calculating intraocular lens power after laser in situ keratomileusis.

PURPOSE: To assess the validity and accuracy of a proposed formula for keratometry (K) readings after laser in situ keratomileusis (LASIK). SETTING: The Eye Center and the Eye Foundation for Research, Riyadh, Saudi Arabia. METHOD: This studied comprised 34 eyes that had LASIK surgery. Refraction and an automated K-reading (auto-K) were performed preoperatively. Refraction, auto-K, and K-reading assessment by the clinical history method and the proposed formula were performed 4 to 12 weeks postoperatively. The proposed formula is K(postop) = K(preop) - [(N(c) - 1) x (R(a-postop) - R(a-preop))/(R(a-postop) x R(a-preop))], where K(postop) is the K-reading after LASIK, K(preop) is the K-reading before LASIK, N(c) is the index of refraction of the cornea (1.376), R(a-postop) is the radius of curvature of the anterior corneal surface after LASIK, and R(a-preop) is the radius of curvature of the anterior corneal surface before LASIK. RESULTS: Twenty patients (10 men, 10 women) were included in the study. The mean age of the patients was 30.58 years +/- 17.68 (SD) (range 18 to 44 years). Preoperatively, the mean spherical equivalent (SE) was -4.99 +/- 2.82 diopters (D) (range -1.12 to -15.00 D), the mean R(a) was 7.76 +/- 0.32 mm (range 7.33 to 8.50 mm), and the mean auto-K reading was 43.45 +/- 1.73 D (range 39.62 to 46.00 D). Postoperatively, the mean SE was +0.02 +/- 0.63 D (range -2.75 to +1.00 D), the mean R(a) was 8.63 +/- 0.53 mm (range 7.80 to 9.92 mm), and the mean K-reading assessed by auto-K, clinical history method, and the proposed formula was 39.17 +/- 2.35 D (range 34.00 to 43.25 D), 38.79 +/- 2.52 D (range 33.1 to 42.78 D), and 38.69 +/- 2.51 D (range 33.1 to 43.0 D), respectively. The results obtained by the proposed formula were similar to those obtained by the clinical history method (P =.098). Auto-K readings significantly overestimated the K-values (P<.0001) when compared to the proposed formula and clinical history method. CONCLUSION: The proposed formula was simple, objective, not dependent on refraction, and as accurate as the clinical history method in determining K-readings after LASIK.

Presumed reactivation of herpes zoster ophthalmicus following laser in situ keratomileusis.

PURPOSE: To report a case of herpes zoster ophthalmicus reactivation following laser in situ keratomileusis (LASIK) for myopia. METHODS: A 54-year-old healthy male underwent uneventful bilateral LASIK for the correction of myopia and astigmatism (-5.75 -3.00 x 20 degrees right eye, -5.50 -3.00 x 170 degrees left eye). Two months following LASIK, an epithelial dendritic lesion appeared in the lower third of the corneal flap of the left eye with vesiculoulcerative lesions of the lateral side of the tip of the nose. RESULTS: The patient was treated with topical and oral antiviral agents and had complete recovery of the lesions in 10 days. CONCLUSIONS: Herpes zoster reactivation may occur following LASIK. Reactivation of herpes zoster in this case could have been coincidental, or secondary to LASIK and the subsequent use of topical corticosteroids following LASIK.