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Human forniceal region is the stem cell-rich zone of the conjunctival epithelium

Harun MH, Sepian SN, Chua KH, Ropilah AR, Abd Ghafar N, Che-Hamzah J, et al.

Hum. Cell, 2013 Mar;26(1):35-40.
PMID: 21748521 DOI: 10.1007/s13577-011-0025-0

The anterior surface of the eye is covered by several physically contiguous but histologically distinguishable epithelia overlying the cornea, limbus, bulbar conjunctiva, fornix conjunctiva, and palpebral conjunctiva. The self-renewing nature of the conjunctival epithelia makes their long-term survival ultimately dependent on small populations of stem cells. Hence, the objective of this study was to investigate the expression of the stem cell genes Sox2, OCT4, NANOG, Rex1, NES, and ABCG2 in cultured human conjunctival epithelium from different conjunctival zones, namely, the bulbar, palpebral and fornix zones. Three samples were taken from patients with primary pterygium and cataract (age range 56-66 years) who presented to our eye clinic at the UKM Medical Centre. The eye was examined with slit lamp to ensure there was no underlying ocular surface diseases and glaucoma. Conjunctival tissue was taken from patients who underwent a standard cataract or pterygium operation as a primary procedure. Tissues were digested, cultured, and propagated until an adequate number of cells was obtained. Total RNA was extracted and subjected to expression analysis of conjunctival epithelium genes (KRT4, KRT13, KRT19) and stem cell genes (Sox2, OCT4, NANOG, Rex1, NES, ABCG2) by reverse transcriptase-PCR and 2% agarose gel electrophoresis. The expression of Sox2, OCT4, and NANOG genes were detected in the fornical cells, while bulbar cells only expressed Sox2 and palpebral cells only expressed OCT4. Based on these results, the human forniceal region expresses a higher number of stem cell genes than the palpebral and bulbar conjunctiva.
Study site: Eye clinic, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia
Phenotypic characterization of culture expanded rabbit limbal corneal keratocytes

Abd Ghafar N, Chua KH, Wan Ngah WZ, Che Hamzah J, Othman F, Abd Rahman R, et al.

Cell Tissue Bank, 2014 Mar;15(1):25-34.
PMID: 23292197 DOI: 10.1007/s10561-012-9360-y

The in vivo quiescent corneal stroma keratocytes need to be transformed to activated state in order to obtain sufficient number of cells either for monolayer evaluation or corneal stroma reconstruction. This study aimed to investigate the phenotypic characterization of corneal stromal cells during culture expansion from the limbal region of the cornea. Isolated corneal keratocytes from limbal tissue of New Zealand White Strain rabbits' corneas (n = 6) were culture expanded until three passages. Keratocytes morphology was examined daily with viability, growth rate, number of cell doubling and population doubling time were recorded at each passage. The expression of collagen type 1, aldehyde dehydrogenase (ALDH), lumican and alpha smooth muscle actin (α-SMA) were detected by RT-PCR. Immunocytochemistry was also used to detect ALDH, α-SMA, collagen type I and Cytokeratin-3 (CK3). Growth kinetic study revealed that the growth rate was low at the initial passage but increase to about two folds with concomitant reduction in population doubling time in later passages. Freshly isolated and cultured keratocytes expressed collagen type 1, ALDH and lumican but α-SMA expression was absent. However, α-SMA was expressed along with the other genes during culture expansion. Keratocytes at P1 expressed all the proteins except CK3. These results suggest that cultured keratocytes maintained most of the gene expression profile of native keratocytes while the emergence of α-SMA in serial passages showed a mix population of various phenotypes. The phenotypic characterization of monolayer keratocytes provides useful information before reconstruction of bioengineered tissue or in vitro pharmaceutical applications.
Fulltext Clinical and Histopathological Effects of Intracameral Ranibizumab in Experimental Trabeculectomy

Azhany Y, Rahman WFWA, Jaafar H, Low JH, Yusuf WNW, Liza-Sharmini AT, et al.

Int J Mol Sci, 2023 Apr 17;24(8).
PMID: 37108535 DOI: 10.3390/ijms24087372

Post-surgical scarring is a known cause of trabeculectomy failure. The aim of this study was to investigate the effectiveness of ranibizumab as an adjuvant anti-scarring agent in experimental trabeculectomy. Forty New Zealand white rabbits were randomised into four eye treatment groups: groups A (control), B (ranibizumab 0.5 mg/mL), C (mitomycin C [MMC] 0.4 mg/mL), and D (ranibizumab 0.5 mg/mL and MMC 0.4 mg/mL). Modified trabeculectomy was performed. Clinical parameters were assessed on post-operative days 1, 2, 3, 7, 14, and 21. Twenty rabbits were euthanised on day 7, and the other twenty were euthanised on day 21. Eye tissue samples were obtained from the rabbits and stained with haematoxylin and eosin (H&E). All treatment groups showed a significant difference in IOP reduction compared with group A (p < 0.05). Groups C and D showed a significant difference in bleb status on days 7 (p = 0.001) and 21 (p = 0.002) relative to group A. H&E staining showed significantly low fibrotic activity (p < 0.001) in group C on both days and inflammatory cell grade in group B on day 7 (p < 0.001). The grade for new vessel formation was significantly low in groups B and D on day 7 (p < 0.001) and in group D on day 21 (p = 0.007). Ranibizumab plays a role in reducing scarring, and a single application of the ranibizumab-MMC combination showed a moderate wound-modulating effect in the early post-operative phase.
Fulltext The Effect of Combined Phacoemulsification and Endo-Cyclophotocoagulation on Intraocular Pressure Fluctuation Assessed by the Water Drinking Test in Patients with Primary Open Angle Glaucoma

Mohammad Razali A, Tang SF, Syed Zakaria SZ, Che-Hamzah J, Aung T, Othman O, et al.

Ophthalmic Res, 2023;66(1):854-861.
PMID: 36917970 DOI: 10.1159/000530072

INTRODUCTION: The aim of this study was to assess the effect of phacoemulsification and endo-cyclophotocoagulation (phaco-ECP) on intraocular pressure (IOP) fluctuation as assessed by the water drinking test (WDT) in primary open angle glaucoma (POAG).
METHODS: This was a prospective observational study carried out at a tertiary referral centre. POAG patients on topical antiglaucoma medications and planned for phaco-ECP were recruited. WDT was performed before surgery and 6 weeks postoperatively by drinking 10 mL/kg of water in 5 min followed by serial IOP by Goldmann applanation tonometry measurements at 15, 30, 45, and 60 min. Mean IOP, IOP fluctuation (difference between highest and lowest IOP), IOP reduction, and factors affecting IOP fluctuation were analysed.
RESULTS: Twenty eyes from 17 patients were included. Baseline IOP was similar before (14.7 ± 2.7 mm Hg) and after (14.8 ± 3.4 mm Hg, p = 0.90) surgery. There was no difference in mean IOP (17.6 ± 3.4 mm Hg vs. 19.3 ± 4.7 mm Hg pre- and postoperative, respectively, p = 0.26) or peak IOP (19.37 ± 3.74 mm Hg vs. 21.23 ± 5.29 mm Hg, p = 0.25), albeit a significant reduction in IOP-lowering medications (2.2 ± 1.15 vs. 0.35 ± 0.93, p < 0.001) postoperatively. IOP fluctuation was significantly greater (6.4 ± 3.2 mm Hg vs. 4.6 ± 2.1 mm Hg, p = 0.015) with more eyes having significant IOP fluctuation of ≥6 mm Hg (11 eyes [55%] vs. 4 eyes [20%], p < 0.001) postoperatively. Factors that were significantly associated with increased postoperative IOP fluctuations were higher preoperative IOP fluctuation (β = 0.69, 95% CI 0.379-1.582, p = 0.004) and more number of postoperative antiglaucoma medications (β = 0.627, 95% CI 0.614-3.322, p = 0.008).
CONCLUSION: Reducing aqueous production with phaco-ECP does not eliminate IOP fluctuation in POAG patients. The increase in postoperative IOP fluctuation suggests increased outflow resistance after phaco-ECP.
Clear lens extraction for the management of primary angle closure glaucoma: surgical technique and refractive outcomes in the EAGLE cohort

Day AC, Cooper D, Burr J, Foster PJ, Friedman DS, Gazzard G, et al.

Br J Ophthalmol, 2018 12;102(12):1658-1662.
PMID: 29453222 DOI: 10.1136/bjophthalmol-2017-311447

BACKGROUND: To describe the surgical technique and refractive outcomes following clear lens extraction (CLE) in the Effectiveness, in Angle-closure Glaucoma, of Lens Extraction trial.
METHODS: Review of prospectively collected data from a multicentre, randomised controlled trial comparing CLE and laser peripheral iridotomy. Eligible participants were ≥50 years old and newly diagnosed with (1) primary angle closure (PAC) with intraocular pressure above 30 mm Hg or (2) PAC glaucoma. We report the postoperative corrected distance visual acuity (CDVA) and refractive outcomes at 12 and 36 months postoperatively for those who underwent CLE.
RESULTS: Of the 419 participants, 208 were randomised to CLE. Mean baseline CDVA was 77.9 (SD 12.4) letters and did not change significantly at 36 months when mean CDVA was 79.9 (SD 10.9) letters. Mean preoperative spherical equivalents were +1.7 (SD 2.3) and +0.08 (SD 0.95) diopters (D) at 36 months. Fifty-nine per cent and 85% eyes were within ±0.5D and ±1.0D of predicted refraction, respectively, at 36 months.
CONCLUSIONS: Mean CDVA in patients undergoing CLE for angle-closure glaucoma appeared stable over the 3-year study period. Refractive error was significantly reduced with surgery but refractive predictability was suboptimal.
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Evaluation of Three-Dimensional Heads up Ophthalmic Surgery Demonstration From the Perspective of Surgeons and Postgraduate Trainees

Cheng TC, Yahya MFN, Mohd Naffi AA, Othman O, Seng Fai T, Yong MH, et al.

J Craniofac Surg, 2021 Oct 01;32(7):2285-2291.
PMID: 33770023 DOI: 10.1097/SCS.0000000000007645

BACKGROUND: To evaluate the satisfaction of surgeons and trainees with three-dimensional (3D) ophthalmic surgery during a demonstration compared to traditional surgery.
METHODS: This validated questionnaire-based study was conducted over 1-month during which Ngenuity 3D surgery was demonstrated. All surgeons and trainees exposed were recruited to complete a questionnaire comprising visualization, physical, ease of use, teaching and learning, and overall satisfaction.
RESULTS: All 7 surgeons and 33 postgraduate students responded. Surgeons reported no significant difference except overall (P = 0.047, paired t-test). Postgraduate trainees reported significantly better experience with 3D for illumination (P = 0.008), manoeuvrability (P = 0.01), glare (P = 0.037), eye strain (P = 0.008), neck and upper back strain (P = 0.000), lower back pain (P = 0.019), communication (P = 0.002), comfortable environment (P = 0.001), sharing of knowledge (P = 0.000), and overall (P = 0.009).
CONCLUSIONS: During early experience, surgeons and trainees reported better satisfaction with 3D overall. Trainees had better satisfaction with 3D in various subcomponents of visualization, physical, ease of use, and education.