Intraocular lens exchange or explantation post cataract surgery

AIM: To report incidence, indications, and visual outcomes of intraocular lens (IOL) exchange/explantation surgery. METHODS: Retrospective analysis of 60 eyes requiring IOL exchange/explantation surgery between 1st January 2017 and 31st December 2022. The overall outcomes as well as comparison between the trainee versus experienced surgeons were analyzed. RESULTS: Out of 39 778 cataract surgeries (with no preexisting ocular co-morbidities) during a six-year period (2017–2022), 60 (0.15%) needed IOL exchange/explantation. Surgeons-under-training performed 36/60 cases (60%) while 24/60 (40%) were by experienced surgeons. The commonest indication was subluxated IOL in 26 (43.3%), followed by dislocated IOL in 20 (33.3%), postoperative refractive surprise in 7 (11.6%), IOL induced uveitis in five and broken haptic in two eyes. Twenty-four (40%) eyes had intraoperative complications during primary surgery. Posterior chamber IOL (PCIOL) was the commonest secondary IOL in 21 (35%) eyes, scleral fixated in 20 (31.6%), anterior chamber IOL (ACIOL) in 13 (21.6%), iris fixated IOL in three (5%) and three eyes (5%) were left aphakic. The mean time between primary and secondary surgery was 168d (168±338.8). Best corrected visual acuity (BCVA) of >20/60 was obtained in 43 eyes (71.66%), 20/80–20/200 in 14 (23.33%), 20/250 in two and hand movements in one. No statistically significant difference in visual outcome was noted at post-op one month between trainees versus experienced surgeons (UCVA 0.45±0.29 vs 0.53±0.32, P=0.20, BCVA 0.34±0.25 vs 0.37±0.26, P=0.69). CONCLUSION: IOL subluxation as the commonest indication and posterior capsular rupture is the commonest intraoperative risk factor. This complication can be effectively addressed with selection of the appropriate secondary IOL achieving good visual outcomes in over 70% of patients

Microsporidial keratitis in India: 16S rRNA gene-based PCR assay for diagnosis and species identification of microsporidia in clinical samples

Purpose: To evaluate 16S rRNA-based polymerase chain reactions for the detection and species identification of the microsporidia that cause keratitis. Methods: Of the 5892 cases of microbial keratitis seen between September 2002 and December 2005, 31 (0.5%) microscopically diagnosed cases of microsporidial keratitis were included in the test group; 103 patients with nonmicrosporidial keratitis constituted the control group. A 16S rRNA-based pan-microsporidian PCR was chosen for the detection of microsporidian DNA. Species level identification was made using species-specific primer sets of Encephalitozoon spp (E. cuniculi, E. hellem, and E. intestinalis). Sequencing and BLAST analysis of amplicons obtained with pan-microsporidian primers were performed for validation. Results: The corneal scrapings from 26 of 31 cases in the test group and 2 of 103 cases in the control group showed a 250- to 280-bp amplicon in PCR by pan-microsporidian primers (sensitivity of 83% and specificity of 98%). The amplicons of 13 of 26 test group samples were identified by species-specific PCR: E. cuniculi, n = 7 (549 bp); E. hellem; n = 3 (549 bp); E. intestinalis; n = 1 (520 bp). The two cases in the control group were identified to be E. cuniculi. The remaining 15 cases (test group) were confirmed to be Vittaforma corneae by sequencing and BLAST analysis. All species were confirmed by sequencing and database homology comparison. Conclusions: This study is the first to validate PCR-based assays for detection of microsporidial DNA in corneal scrapings. Pan microsporidian PCR can be a useful adjunct with smear examination in the diagnosis of microsporidial keratitis