حمیدرضا حسنی

Since prevalence of the Severe Acute Respiratory Syndrome 2 (SARS-CoV-2), millions of infected people presented with various manifestations. Some studies report ocular complications, such as conjunctivitis and sub-conjunctival haemorrhage, as an initial manifestation of Corona Virus Disease 2019 (COVID-19). This article aims to report unilateral acute anterior non-granulomatous uveitis manifested in COVID-19. Systemic work up and laboratory results, confirmed the diagnosis.

A 37-year-old female patient with a history of hypothyroidism, fever, weakness and lethargy, throbbing chest pain, non-productive cough and diffuse painful redness of the left eye with positive COVID-19 polymerase chain reaction (PCR) test from nasopharyngeal and oropharyngeal swabs and erythrocyte sedimentation rate of 43 mm/h is reported.

Demographically, the patient was a 37-year-old female. On ophthalmologic examination, right and left eye vision were 10/10 and 5.10, respectively. The relative afferent pupillary defect was negative. External ocular motility was within normal limits. On slit lamp biomicroscopy, conjunctival peri-limbal injection, 2+ cells and 3+ flares in the anterior chamber of the left eye, posterior synechiae was seen and the vitreous cavity was clear. Right eye examination was completely normal.

Covid-19 can be associated with ocular involvement as acute non-granulomatous anterior uveitis, which can be prevented ocular complications and vision loss if diagnosed and treated early. Acute anterior non-granulomatous uveitis can also be an early sign of Covid-19 disease, which should raise clinical suspicion of the disease and therefore reduce the morbidity and mortality of Covid-19 disease by starting timely treatment.

In this paper a novel single layer dual band reflectarray antenna with orthogonal polarization in X and Ku bands for satellite communication is proposed. The planar reflectarray prototype is fabricated and the results are compared with those of simulations and discussed. The unit cell consists of dual split rectangle loops for lower band frequency at 11. 5 GHz and gradually decreasing dipoles for upper band at center frequency of 14 GHz. Both of the designed elements have more to 6000 phase variation that achieved by varying the length of the each elements. A thin dielectric substrate of thickness 0. 8mm placed above an air layer of 2mm is used. The reflectarray is center fed by a linearly polarized pyramidal horn antenna. The X band elements have -1dB gain bandwidth of about 17. 4% covering 11-13 GHz and the Ku band has about 13% bandwidth covering 12. 7-14. 5 GHz. The measured antenna gain at 11. 5 GHz is 23. 9 dB and at 14 GHz is 26. 1 dB showing aperture efficiency of 41% and 45%, respectively.

To determine the effect of retained donor Descemet membranes (DMs) on visual outcomes following deep anterior lamellar keratoplasty (DALK). In this retrospective comparative study, keratoconic eyes undergoing DALK using the big-bubble technique were enrolled. A bared DM was achieved in all cases. A donor cornea without (group 1; 48 eyes) or with (group 2; 22 eyes) DM was sutured to the recipient bed. The 2 groups were compared in terms of best spectacle-corrected visual acuity, keratometric astigmatism, refractive error, contrast sensitivity (CS), higherorder aberrations (HOAs), and central graft thickness at least 3 months after complete suture removal. The mean follow-up duration was 23.2±6.9 months in group 1 and 26.5±6.5 months in group 2 (P = 0.61). The postoperative best spectacle-corrected visual acuity was 0.18±0.08 logMAR and 0.24±0.30 logMAR, respectively (P = 0.36). The 2 groups had comparable postoperative keratometric astigmatism, spherical equivalent refraction, and HOAs. In terms of CS, however, group 1 demonstrated better results at a low spatial frequency. The mean postoperative central graft thickness was greater in group 2 (589.8±34.5 mm) than in group 1 (523.6±63.0 mm; P< 0.001). DALK using the big-bubble technique for keratoconus may give better results in terms of CS if a donor cornea without DM is transplanted.

To evaluate the effect of amniotic membrane transplantation (AMT) in the management of acute severe ocular chemical burns. This randomized clinical trial was performed in eligible patients with grade III & IV acute chemical burn who randomly received conventional medical therapy (15 eyes) versus combined medical & amniotic membrane transplantation (15 eyes). Main outcome measures were corneal epithelial healing time and improvement in perilimbal ischemia. Secondary outcome measures included visual acuity, corneal transparency, vascularization, symblepharon formation and complications. 30 eyes of 28 patients (26 males and 2 females) with a mean age of 256.8 years (12-49) were enrolled in this study. Corneal epithelial defect healed within 74.4148.07 days (22-180 days) in the amniotic membrane group versus 99.6736.8 (56-170 days) in controls (P= 0.163). Perilimbal ischemia improved in 76.4142.8 days in the amniotic membrane group versus 89. 1644.6 days in the control group (P= 0.482). Mean final visual acuity was 0.0240.655 LogMAR versus -0.0720.5 LogMAR in the amniotic membrane and control groups, respectively (P= 0.655). In the amniotic membrane group, symblepharon developed in 6 eyes versus 10 eyes in the control group. Totally 3 eyes developed corneal perforation whom undergone tectonic corneal graft. Compared to conventional medical therapy, combined AMT and medical therapy does not improve perilimbal ischemia or accelerate corneal epithelization. It also does not decrease corneal vascularization or improve visual acuity.

To determine changes in streoacuity in anisometropic myopic eyes after photorefractive keratectomy (PRK). This quasi-experimental clinical trial was performed in myopic patients with at least 1 D of in anisometropia spherical, astigmatic or spherical equivalent who underwent photorefractive keratectomy (PRK) using the Technolas 217 Z excimer laser machine. Changes in streoacuity were evaluated. TNO and butterfly stereoacuity tests before PRK and at 2 weeks, 1 month and 3 months after PRK. Overall, 98 eyes of 49 patients (71. 4% male and 28. 6% female subjects) with mean age of 285. 5 years and mean myopia of -3. 321. 74D and mean astigmatism of 1. 31. 3 D were enrolled in study. Preoperative mean stereoacuity values were 102103. 44 sec/arc and 56. 841 sec/arc by TNO and butterfly stereoacuity tests which changed to 90110. 52 sec/arc (P=0. 009)، and 56. 541. 3 sec/arc (P=0. 80) respectively 3 months after PRK. Total proportion of improvement in stereoacuity values was 10. 2% and 6. 12% by TNO and Butterfly Stereoacuity tests respectively. Stereoacuity improves after photorefractive keratectomy in anisometropic myopic patients. This improvement is more significant with TNO test than the Butterfly Stereoacuity test.

To evaluate the effect of location and size of chalazia on refractive error, corneal topography and visual acuity. This randomized non-controlled clinical trial was conducted on patients with chalazion aged more than 3 years with minimum duration of one month. All patients underwent chalazion excision by the internal or external approach. Two-hundred and fifty-three eyelids of 228 eyes of 195 patients (85 male, 110 female) with mean age of 31±14 (range 7-71) years underwent chalazion excision. Mean duration of presenting symptoms was 4±2.8 (range 1-24) months. Chalazia were single in 172 (88.2%) and multiple in 23 (11.8%) patients. Single chalazia were distributed almost identically in medial, central and lateral sites of lids. Mean difference of pre- and postoperative best-corrected visual acuity was 0.0004 LogMAR (P=0.3). Mean differences in pre- and postoperative values of sphere, difference in keratometry (DK) or cylinder and spheric equivalent (SE) were 0.005 D (P= 0.9), 0.17 D (P<0.001) and 0.006 D (P= 0.08), respectively. Mean differences between pre- and postoperative topographic indices including surface regularity index, surface asymmetry index, keratometry (D) and potential visual acuity (LogMAR) were 0.13 (P<0.0001), 0.09 (P<0.0001), 0.34 (P<0.0001) and 0.05 (P<0.0001), respectively. In comparison of single-central-firm chalazion with multiple-peripheral-soft type chalazia, the difference in mean DK was 0.53±0.15 D (P<0.0001) and the difference of mean changes of SE was 0.45±0.11 D (P=0.2). Mean difference of DK was 0.1±0.06 D in upper lid (P= 0.03) and 0.02±0.03 in lower lid (P=0.1). Excision of chalazion can decrease corneal astigmatism and irregularity, which is more prominent in single-central-firm and upper lid chalazia. In children who are at risk of amblyopia, any attempt to improve the refractive state is worthwhile.

In spite of rapid advances in keratorefractive surgery in recent decades, the most common method for refractive error correction throughout the world is glasses, the discovery of which is attributed to the Persians. Other advantages include protection of the eye against trauma and radiations, correction of phorias and tropias and cosmetic reasons. The purpose of this article is to describe and review different components of glasses (frame, temple and lens), sunglasses, photochromic and polarizing glasses, antireflective and mirror coats, progressive additional lenses and also recommendations about frame selection.