Evaluation of corneal stromal changes in vivo after laser in situ keratomileusis with confocal microscopy

PURPOSE: To assess by in vivo confocal microscopy the modifications of the corneal stroma after laser in situ keratomileusis (LASIK) for myopia. DESIGN: Nonrandomized comparative (self-controlled) trial. PARTICIPANTS: Sixteen eyes of 13 patients were examined before surgery and at days 8, 30, and 90, and 9 eyes were examined at 6 months postoperatively using an in vivo confocal microscope. TESTING/INTERVENTION: Stromal morphologic changes, keratocyte density, flap thickness, and subclinical haze were evaluated and compared at different time points. LASIK was performed with a Flapmaker microkeratome (Solan Ophthalmic products, Jacksonville, FL) and a Lasersight LSX excimer laser (LaserSight Technologies Inc., Winter Park, FL). MAIN OUTCOME MEASURE: Confocal microscopy results. RESULTS: Microfolds at the Bowman's layer were found in most eyes, as well as variable reflectivity particles (pa) located at the interface level in all eyes examined postoperatively. The density of these particles significantly decreased with time with, respectively, 504 +/- 101 pa/mm2 at day 8 and 380 +/- 111 pa/mm2 at day 30 (P = 0.003), 332 +/- 100 pa/mm2 at month 3 and 312 +/- 40 pa/mm2 at month 6. The mean flap and the activated-cells area thicknesses were, respectively, 102 +/- 26 microm and 61 +/- 19 microm and showed significant negative correlation (P < 0.0001). The intensity of the added peak (47.3 microm 8.6%), corresponding to the subclinical haze, realized by Z-scan measure, was also negatively correlated with flap thickness (P = 0.01). Keratocyte (k) density quantified in the posterior stroma significantly increased from day 0 (480 +/- 67 k/mm2) to day 8 (701 +/- 41 k/mm2, P < 0.0001 compared with day 0) and day 30 (917 +/- 143 k/mm2, P = 0.0006, compared with day 0) but significantly decreased at 3 months postoperatively (597 +/- 56 k/mm2, P < 0.0001 compared with day 30) to reach the initial level at month 6 (502 +/- 41 k/mm2, nonsignificant compared with day 0). There was no correlation between preoperative or postoperative spherical equivalent and the density of particles, keratocytes, and the haze intensity. CONCLUSIONS: This study confirms the presence of microfolds and particles at the interface level, as well as subclinical impairment. Evaluation of keratocyte density constitutes a major contribution of confocal microscopy toward an understanding of the keratocyte response to corneal wound healing after corneal refractive surgery. Moreover, flap thickness seems to be involved in the postoperative cellular activation with a higher response when thin.     

Dissociated optic nerve fiber layer appearance of the fundus after idiopathic epiretinal membrane removala

Purpose

To report the appearance of the fundus, that is seen frequently after removal of an idiopathic epiretinal membrane and which we refer to as the dissociated optic nerve fiber layer appearance.

Formation of intercellular spaces and junctions in regenerating rabbit corneal endothelium

Rabbit corneal endothelium was destroyed over a diameter of 10 mm using liquid nitrogen applied for 15 sec to the anterior surface. The corneas were afterwards removed at different periods, from 1 day to 2 months and studied by light microscopy after silver impregnation, by transmission electron microscopy, and by scanning electron microscopy in order to study the formation of new intercellular spaces and junctions in the regenerating endothelium.The intercellular spaces and junctions are all reconstituted at the end of the fifth day, when the whole of Descemet's membrane is entirely covered by cells. This period also corresponds to the recovery of the endothelial function. The dynamics of the formation of intercellular spaces are described, and the rapid appearance of two types of junctions as soon as contact between cells is completed. Junctions of the first type, always at the apex of the cells, are single or multiple with adjacent intra-cytoplasmic opacities and correspond to the junctional elements of the “terminal bar”. Junctions of the second type, on the lateral plasma membranes of the cells, are not constantly observed; they are straight, or curved. or circular; their length is variable, and they possess a periodicity in their structure, and correspond to gap junctions.     

Management of subretinal and vitreous cysticercosis: role of photocoagulation and surgery

Treatment of intraocular cysticercosis requires selection of the proper method, prevention of complications, and careful follow-up. Small subretinal cysticercus can be treated with xenon or argon photocoagulation. Macular cysticercus are extracted through a sclerochoroidal incision. Large cysticercus can be removed in selected cases with an outcome probe placed in the subretinal space. Cysticercus in the vitreous should be removed with a suction-cutter probe via the pars plana.     

Restoration of fusion in children with intracranial tumors and incomitant strabismus

PURPOSE: Intracranial tumors may cause eye misalignment and interruption of sensory fusion. The ocular misalignment may be permanent or may be corrected after tumor treatment with or without specific strabismus treatment. This report analyzes the binocular vision outcome of children with misaligned eyes from brain tumors who regain orthotropia. DESIGN: A retrospective noncomparative case series. PARTICIPANTS: Twenty-three surviving children less than 18 years of age with a new heterotropia and absence of fusion associated with the development of a brain tumor. INTERVENTIONS: Tumor resection/radiation/chemotherapy and necessary strabismus management. MAIN OUTCOME MEASURE: Stereopsis (>/= 4 of 10 circles) measured with the Randot II stereo test at near fixation. RESULTS: Fourteen children regained orthotropia either after tumor therapy, strabismus treatment, or both. Ten of these 14 children with realigned vision regained high-grade stereovision. Nine patients did not regain orthotropia and were excluded. The mean age at tumor diagnosis of the fusing group was 9.9 years (range, 3-17 years) compared with 8.5 years (range, 6-12 years) in the four realigned nonfusing patients. The mean duration of misalignment was 12 months (range, 2-51 months) for the fusing group, and 45 months (range, 14-120 months) for the nonfusing group. CONCLUSIONS: Children and adolescents with brain tumor-associated eye misalignment may regain the ability to fuse if their misalignment can be corrected. An improved prognosis was noted for those patients when the misalignment had been present for a shorter duration. These data suggest that the outcome may be better for incomitant strabismus than that reported for acute comitant esotropia.     

Computed tomography in the diagnosis and prognosis of open-globe injuries

OBJECTIVE: Determine sensitivity, specificity, and prognostic signs of orbital and ocular computed tomography (CT) in diagnosing patients with open globe injury. DESIGN: Randomized masked review of computed tomograms and retrospective clinical correlation of patients with ocular trauma. PARTICIPANTS: Two hundred patients who underwent CT evaluation for ocular trauma between 1989 and 1993. METHODS: CTs were read by three masked observers; findings were tabulated and compared for variability among observers; sensitivity and specificity were calculated and CT findings were grouped according to visual outcome retrieved from record review. RESULTS: In the absence of clinical information, sensitivity and specificity were 75% and 93%, respectively. The positive predictive value ranged from 88% to 97%, with a calculated overall positive predictive value of 95%. Patients who had a poor visual outcome (visual acuity <2/200) or who underwent enucleation had significantly more CT findings than patients with a good visual outcome. Vitreous hemorrhage, absence of lens, and severe distortion of vitreous space are among the most common CT findings associated with poor visual outcome. CONCLUSIONS: CT is not sensitive enough to be solely relied upon for diagnosis of all open globe injuries. CT findings only complement clinical findings, increasing the clinician's overall ability to make an accurate diagnosis of open globe injury, and may provide useful prognostic information regarding visual outcome.     

A prospective study on ocular hypertensive and antiinflammatory response to different dosages of fluorometholone in children.

OBJECTIVE: To investigate the ocular hypertensive and antiinflammatory response to different dosages of fluorometholone (FML). DESIGN: Prospective clinical trial with randomization of fellow eyes to different postoperative treatment. PARTICIPANTS: Thirty-one consecutive children undergoing bilateral symmetrical strabismus operation. INTERVENTION: Among 31 children who received bilateral squint operations, one eye was randomized to receive topical FML six times daily (group 1), whereas the other eye received topical FML three times daily (group 2), both for 4 weeks. Intraocular pressure (IOP) and antiinflammatory response were measured serially in the postoperative period for 8 weeks. MAIN OUTCOME MEASURES: Intraocular pressure was measured on the day before surgery and on postoperative days 1, 3, 6, 13, 20, 27, 41, and 55. The antiinflammatory response was also assessed subjectively and objectively at days 6, 13, 20, and 27 after the operations. Peak IOP, net increase in IOP, and antiinflammatory responses in the two study groups were analyzed. RESULTS: Thirty-one children, age 3 to 9 years, (mean +/- standard deviation [SD], 5.52 +/- 1.81) participated in the study. Intraocular pressure increased significantly in both groups compared with the preoperative values (P < 0.001). The peak IOP ranged from 12.00 to 31.00 mmHg and 12.30 to 25.00 mmHg in groups 1 and 2, respectively. The mean peak IOP (19.00 +/- 5.06 mmHg vs. 17.13 +/- 3.32 mmHg) was significantly higher in group 1 (P < 0.001). The net increase in IOP was similar (mean +/- SD, 4.37 +/- 4.79 vs. 2.57 +/- 3.32 mmHg; P = 0.005). Ranges of the net IOP increase were -1.00 to 16.00 mmHg and -2.50 to 10.30 mmHg in groups 1 and 2, respectively. Children in group 1 reached the peak IOP earlier than those in group 2 (median, 6 vs. 13 days; P = 0.033). However, there was no significant difference in antiinflammatory response between the two groups. CONCLUSIONS: Ocular hypertension occurs in a dose-dependent manner in children treated with FML. Children in group 1 had a quicker onset and more severe ocular hypertensive response than those in group 2. It would be desirable to monitor the IOP regularly when FML is used with a high frequency and for a long duration in children.