Tushar Agarwal

Microbial keratitis after laser in situ keratomileusis.

PURPOSE AND METHOD To review the literature on microbial keratitis reported after laser in situ keratomileusis (LASIK). RESULTS Forty-one eyes have been reported to have microbial keratitis after LASIK. The causative organisms vary from gram positive bacteria to atypical mycobacteria, fungal, and viral pathogens. The infection is usually acquired intraoperatively, but may also be caused by postoperative contamination. A majority of the patients present within 72 hours of the surgery with an acute onset of symptoms. Management of microbial keratitis after LASIK includes aggressive topical fortified antibiotic therapy, irrigation of stromal bed with antibiotic solution after lifting the flap, and sending the scraping of the infiltrate for microbiological evaluation. The keratitis heals with scarring and a best spectacle-corrected visual acuity of 20/40 or better can be obtained in the majority of the patients. CONCLUSION Microbial keratitis is a sight-threatening complication of LASIK.

Management of Corneal Perforation

Corneal perforation may be associated with prolapse of ocular tissue and requires prompt diagnosis and treatment. Although infectious keratitis is an important cause, corneal xerosis and collagen vascular diseases should be considered in the differential diagnosis, especially in cases that do not respond to conventional medical therapy. Although medical therapy is a useful adjunct, a surgical approach is required for most corneal perforations. Depending on the size and location of the corneal perforation, treatment options include gluing, amniotic membrane transplantation, and corneal transplantation.

Ultrasound Biomicroscopy-Guided Assessment of Acute Corneal Hydrops

OBJECTIVE To analyze the morphologic features of acute hydrops and treatment success using ultrasound biomicroscopy (UBM). DESIGN Prospective interventional case series. PARTICIPANTS Fourteen patients (14 eyes) affected by keratoconus with acute corneal hydrops. INTERVENTION Patients with acute hydrops were treated with intracameral injection of 0.15 ml of 14% perfluoropropane (C₃F₈) gas. MAIN OUTCOME MEASURES The parameters evaluated on UBM included the location and length of the Descemets membrane (DM) tear and corneal thickness at the central corneal thickness at the area overlying the DM tear (CT₀), corneal thickness 2.5 mm from the central point (CT₂.₅), and peripheral corneal thickness 2.0 mm from the scleral spur toward the corneal side (CT(P)). The ratio of CT₂.₅ to CT₀ was calculated to obtain the hydrops resolving index (HyRI). RESULTS The DM tear was visualized with UBM in all cases and slit-lamp microscopy in 9 of 14 eyes. The mean length of DM tears at presentation was 1.74 ± 0.77 μm. Patients with zone 3 corneal edema had a longer DM tear compared with patients with zone 2 corneal edema (1.27 ± 0.55 vs 2.02 ± 0.79 μm, respectively, P = 0.09). Significant positive correlations were seen between DM tear length and CT₂.₅ and CT(p) (r = 0.790, P = 0.020 and r = 0.766, P = 0.027, respectively). An intracameral gas bubble was seen abutting the edges of the tear in all cases. At the 6-week follow-up, the apposition of the DM and the overlying stroma occurred in all eyes, and resolution of epithelial edema and intrastromal cysts were seen in 11 of 13 cases (84.6%) and 12 of 13 cases (92.3%). The mean values of CT₀, CT₂.₅, and CT(p) at presentation were 2359.69 ± 582.26 μm, 1911.15 ± 502.60 μm, and 1156.46 ± 275.77 μm, respectively, which decreased to 398.15 ± 31.65 μm (P = 0.0), 453.46 ± 68.45 μm (P = 0.0), and 638.00 ± 62.17 μm (P = 0.0), respectively. The mean HyRI showed a significant increase from 0.80 ± 0.05 at the time of presentation to 1.13 ± 0.12 (P = 0.03) at 3 months follow-up. CONCLUSIONS Ultrasound biomicroscopy is a useful tool for quantitative and qualitative study of the morphologic features of acute hydrops. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Randomized clinical study for comparative evaluation of fourth-generation fluoroquinolones with the combination of fortified antibiotics in the treatment of bacterial corneal ulcers.

Purpose: Comparative evaluation of efficacy of monotherapy with moxifloxacin (0.5%) or gatifloxacin (0.3%) with combination therapy of cefazolin (5%) and tobramycin (1.3%) in treatment of bacterial corneal ulcers. Methods: Patients diagnosed with bacterial keratitis (ulcer diameter 2-8 mm) were randomized to 1 of the 3 treatment groups (tobramycin 1.3% and cefazolin 5%, gatifloxacin 0.3%, or moxifloxacin 0.5%). After obtaining corneal scrapings, assigned study medication was instilled hourly for 48 hours and tapered as per clinical response. Healing of ulcer, duration to cure, adverse reactions, antibiogram profile, treatment failures, final visual acuity, and corneal opacity size were evaluated. Results: A total of 61 patients were enrolled [cefazolin and tobramycin (n = 20), gatifloxacin (n = 21), and moxifloxacin (n = 20)]. Overall, 57 patients (93%) healed on treatment. On comparison of the mean time taken to heal, no statistically significant difference was found among all the 3 treatment groups (P = 0.98). Positive bacterial culture was obtained in only 38 patients (62%). There was no significant difference in the bacterial isolates in each treatment group. There were 4 (7%) treatment failures (perforation or nonhealing ulcer): 1 (5%) each in moxifloxacin and gatifloxacin group and 2 (10%) in fortified antibiotics group. All regimens were well tolerated. Conclusion: The study failed to find a difference in the efficacy of monotherapy with fourth-generation fluoroquinolones in the treatment of bacterial corneal ulcers of 2-8 mm size when compared with combination therapy of fortified antibiotics.

Adjuvant Role of Amniotic Membrane Transplantation in Acute Ocular Stevens-Johnson Syndrome: A Randomized Control Trial.

PURPOSE To evaluate the adjuvant role of amniotic membrane transplantation (AMT) in cases of acute ocular Stevens-Johnson syndrome (SJS). DESIGN Prospective randomized controlled clinical trial. PARTICIPANTS Twenty-five patients (50 eyes) with acute ocular SJS who presented within 4 weeks of onset of symptoms were recruited. METHODS The eyes were randomized into 2 groups that underwent either AMT with medical therapy (MT; n = 25) or standard MT alone (n = 25). The patients were evaluated at presentation and during follow-up at 1 week and 1, 3, and 6 months. The parameters evaluated were the best-corrected visual acuity (BCVA), Schirmer test, tear film breakup time (TBUT), conjunctival congestion, corneal haze, vascularization, conjunctivalization, and limbal stem cell involvement. Lid edema, symblepharon, ankyloblepharon, ectropion, entropion, trichiasis, and metaplastic lashes also were analyzed. MAIN OUTCOME MEASURES Maintenance of BCVA and stable ocular surface. RESULTS At the end of 6 months, the mean BCVA was significantly better in the AMT group (0.068±0.10 logMAR units) compared with the MT group (0.522±0.52 logMAR units; P = 0.042). The mean TBUT in the AMT and MT groups was 9.92±4.1 and 6.96±4.5 seconds, respectively (P = 0.015). The mean Schirmer test results in the AMT and MT groups were 15.4±6.3 and 8.64±5.4 mm, respectively (P < 0.001). Conjunctival congestion persisted in 44% (11/25) in the MT group compared with 4% (1/25) in the AMT group (P = 0.03) at the end of the 6-month follow-up. No case in the AMT group demonstrated corneal haze, limbal stem cell deficiency, symblepharon, ankyloblepharon, or lid-related complications. Among eyes in the MT group, corneal haze occurred in 44% (11/25; P = 0.001), corneal vascularization and conjunctivalization in 24% (6/25; P = 0.03), symblepharon in 16% (4/25; P = 0.12), ankyloblepharon in 4% (1/25; P = 1.00), ectropion and entropion in 8% (2/25; P = 0.47), and trichiasis and metaplastic lashes in 24% (6/25; P = 0.03) eyes. CONCLUSIONS Amniotic membrane transplantation is a useful adjunct to conventional MT in maintaining BCVA and a stable ocular surface in cases of acute ocular SJS. Furthermore, the adjunctive use of AMT also helps to prevent intermediate-term ocular cicatricial sequelae.

Modification in descemet-stripping automated endothelial keratoplasty: "Hitch suture" technique.

Purpose: To describe a new modification in Descemet-stripping automated endothelial keratoplasty, using a “hitch suture” to unfold the donor lenticule inside the recipients eye. Methods: The technique was used in 2 eyes of 2 patients with bullous keratopathy after complicated cataract surgery. A hitch suture was created in both the donor lenticules before inserting the folded graft in the recipients anterior chamber. The hitch suture was pulled through a limbal stab incision to unfold the donor lenticule in both cases. Results: No intraoperative problems were encountered. The grafts were well centered with corneal edema. The central part of the graft cleared over a period of 10 to 14 days. Conclusion: The technique of using a hitch suture to unfold the graft eliminates the problems associated with this difficult step of the surgery. The hitch loop can be easily made at the edge of the graft and can be pulled using a Sinskey hook through 1 of the stab incisions. We believe that this simple modification in this surgery would help simplify the learning curve of the procedure and increase its chances of success.

Update on diagnosis and management of Descemet's membrane detachment.

Purpose of review Descemets membrane detachment (DMD) is commonly encountered after intraocular surgery and ocular trauma. Although its occurrence has been known for a long time, the disease course and its optimal management is not yet fully understood. This review aims to present an update on current trends in diagnosis and management of DMD. Recent findings Different causes as well as a variable course of disease exist for DMD. Although some DMDs reattach spontaneously with a good visual outcome, some corneas clear without the need for an attached membrane and a few corneas do not clear in spite of an attached Descemets membrane. DMDs may be treated either conservatively or surgically, with many surgeons favouring an early surgical intervention especially for scrolled, extensive and sight-disabling DMDs. However, due to an unknown course of the disease, exact timing and nature of surgical intervention could not yet been fully defined. Summary Most DMDs can now be recognized and managed successfully with good visual outcome. However, optimal timing and treatment strategy for different DMDs remain an area to be explored for the best visual recovery for patients.

In vitro susceptibility of bacterial keratitis isolates to fourth-generation fluoroquinolones.

Purpose. To study the microbiological profile of bacterial keratitis in Northern India and to determine the antibiotic sensitivity pattern of bacterial keratitis isolates to fourth-generation fluoroquinolones. Methods. Laboratory records of all consecutive cases of clinically suspected bacterial corneal ulcers were retrospectively reviewed. Data noted included microorganism isolated and antibiotic culture sensitivity to cefazolin, tobramycin, gatifloxacin, and moxifloxacin. In vitro susceptibility toward individual antibiotics was determined and compared with the potential in vitro susceptibilities to cefazolin-tobramycin, cefazolin-gatifloxacin, and cefazolin-moxifloxacin combinations. Results. A total of 292 bacterial isolates were identified. Of these, 255 (87.3%) were Gram-positive and 37 (12.7%) were Gram-negative. Staphylococcus epidermidis (n=227, 77.7%) was the most common organism. Overall susceptibility of isolates was 95.52% to gatifloxacin, 92.83% to moxifloxacin, 90.07% to tobramycin, and 83.56% to cefazolin (p<0.000). Organisms which showed resistance to fourth-generation fluoroquinolones included Staphylococcus epidermidis, Pseudomonas aeruginosa, viridans streptococci, Streptococcus pneumoniae, Staphylococcus aureus, and Escherichia coli. Susceptibilities to gatifloxacin and moxifloxacin were comparable with each other (p=0.312) and with potential susceptibilities to cefazolin-tobramycin (p=0.479), gatifloxacin-cefazolin (p=0.134), and moxifloxacin-cefazolin (p=0.412) combinations. Conclusions. Monotherapy with moxifloxacin or gatifloxacin can be an effective alternative to cefazolin-tobramycin combination as a first-line empirical therapy for bacterial keratitis. The addition of cefazolin to a fourth-generation fluoroquinolone is of limited value.

Refractive outcomes of laser in situ keratomileusis after flap complications.

Purpose: To study the refractive and visual outcomes, including surgically induced astigmatism, of laser in situ keratomileusis (LASIK) after flap buttonholes and incomplete flaps. Setting: Rajendra Prasad Center for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. Methods: This was a retrospective case series of 15 patients (15 eyes) who had LASIK after flap complications (6 eyes with buttonholes and 9 with incomplete flaps). The second surgery was performed after the refraction was stable for 2 months. The refractive and visual outcomes were studied. Results: After the flap complication, the spheroequivalent did not change significantly (P = .78) but the mean pachymetry changed from 523.6 μm ± 23.14 (SD) to 530.4 ± 23.96 μm (P = .04) and the mean absolute cylinder changed from 0.63 ± 1.01 diopter (D) to 0.88 ± 0.87 D (P = .026). The second surgery was performed at a mean interval of 6.2 months (range 3 to 17 months). Two eyes had flap complications (irregular flaps) again after the second surgery. At the 6‐month follow‐up, the mean spheroequivalent was −0.34 ± 0.65 D and the mean cylinder was 0.15 ± 0.19 D × 83.6. Thirteen eyes (86.66%) were within 0.5 D of the attempted correction. Post‐LASIK complications included diffuse lamellar keratitis (1 eye), epithelial ingrowth (1 eye), and flap striae (2 eyes). After the flap complication, no eye lost 2 or more lines of best spectacle‐corrected visual acuity (BSCVA); but after the second surgery at 6 months, 1 eye had lost 2 lines of BSCVA. Six months postoperatively, all eyes had a BSCVA of 20/40 or better. Conclusion: Laser in situ keratomileusis after flap complications is associated with good refractive and visual outcomes; however, there is a higher risk for intraoperative and postoperative complications after the second surgery.

Outcomes of therapeutic penetrating keratoplasty from a tertiary eye care centre in northern India.

Purpose: The aim was to study the outcomes and results of therapeutic penetrating keratoplasty (Th PK) at a tertiary eye care hospital in northern India. Methods: In this retrospective interventional study, a cohort of 506 eyes that underwent a Th PK for microbial keratitis was evaluated. Th PK was performed in cases of recalcitrant microbial keratitis with impending perforation (descemetocele formation) or perforation (>3 mm). Medical records were reviewed for demographic details, risk factors, ulcer and perforation size, microbiological investigations, size of donor and recipient beds, postoperative complications, and anatomical and visual outcomes. Results: Anatomical success was seen in 454 eyes (89.7%). Preoperatively, the corrected distance visual acuity was <3/60 in 495 eyes (97.8%); after performing the Th PK, the corrected distance visual acuity was <3/60 in 249 eyes (49.2%), 3/60 to 6/60 in 182 eyes (35.9%), and >6/60 in 75 eyes (14.8%). Eyes with smaller grafts (<9 mm) had better anatomical and visual outcomes compared with eyes with larger grafts (9–11 mm; P = 0.03 and >11 mm; P = 0.0). A higher success rate was achieved with pure bacterial or fungal organisms rather than with mixed infections. A higher incidence of secondary glaucoma was seen in eyes with perforated ulcers (29.36%; 111/378) than in eyes without perforation (11.71%; 15/128) (P <.01) and in eyes with larger graft sizes (>11 mm and 9–11 mm) than in eyes with smaller graft sizes (<9 mm) (P <0.01). Conclusions: Th PK has a definitive role in the management of severe and refractory keratitis with a high success in restoring anatomical integrity and providing useful vision. Better outcomes may be achieved with early intervention before perforation or limbal/scleral extension.