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Background: Transscleral cyclophotocoagulation (TSCPC) is most commonly used in patients with neovascular glaucoma (NVG) associated with proliferative diabetic retinopathy (PDR) in whom maximal hypotensive medications have failed to reduce intraocular pressure (IOP) to the desired level, and glaucoma surgery cannot be carried out. Options for CPC can be performed using a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser or diode laser. Purpose: To compare the efficacy of TSCPC performed with the 1,064-nm Nd:YAG laser versus 810-nm diode laser in patients with painful NVG associated with PDR over a 12-month follow-up period. Material and Methods: A prospective cohort study was carried out on 58 type 2 diabetics (58 eyes) who received a 1,064-nm Nd:YAG laser TSCPC or 810-nm diode laser TSCPC for painful NVG associated with PDR, with regular follow-up visits over 12 months and had no previous history of treatment with CPC. IOP between 6 and 21 mmHg (or a reduction in IOP of ≥ 30% from baseline IOP) and no ocular pain at 12 months was the primary outcome measure. Results: The success rate at 12 months was 75% and 77% for eyes that received Nd:YAG laser TSCPC and diode laser TSCPC, respectively (p = 0.86). In the Nd:YAG laser TSCPC and diode laser TSCPC groups, the IOP reduced by 46% and 45%, respectively (p = 0.34) from baseline values of 38.0 mmHg and 36.0 mmHg, respectively (p = 0.96) at month 12 after TSCPC. At month 12 after CPC, the BCVA in patients with preserved pattern vision improved in both groups (p = 0.41). The rate of ocular complications was, however, higher in the diode laser TSCPC group (71% versus 33%, p = 0.004). Conclusion: Nd:YAG laser TSCPC resulted in a reduction in IOP to ≤ 21 mmHg at month 12 in 75%, and diode laser TSCPC, in 77% of patients with NVG associated with PDR. The number of sessions required for treatment success was 3.2 times larger for Nd:YAG laser CPC than for diode laser CPC. Both these types of CPC are safe and can be repeatedly used to improve treatment efficacy.

Background: Bleeding in vitreoretinal patients during and early after vitrectomy is still a challenge that needs to be addressed. Purpose: To assess the effect of irrigation fluid temperature on intraocular bleeding time in rabbits during vitrectomy. Material and Methods: Twelve Chinchilla rabbits (24 eyes) were included in this study and divided into four groups of 3 animals (6 eyes) each based on vitrectomy irrigation fluid temperature: group 1 (5° C), group 2 (10° C), group 3 (22° C), and group 4 (36° C). The ambient operating room temperature was between 22 °С and 24 °С. Results: The duration of intraocular bleeding in groups 1, 2, 3 and 4 was 88.3 ± 46.0 s, 34.8 ± 30 s, 63 ± 23.5 s, and 21.1 ± 9.5 s, respectively. Conclusion: In a rabbit model of intraocular bleeding, use of irrigation fluid of 36 °С (i.e., conditions of mild hypothermia) resulted in shorter intraocular bleeding in the perioperative period of vitrectomy compared to conventional use of room-temperature irrigation fluid (21.1 ± 9.5 s against 63 ± 23.5 s). Mild hypothermia may be recommended for use in vitreoretinal surgery in patients with a high risk of bleeding.

Background: Heat exchange characteristics include not only temperatures and temperature distribution, but also heat flux (HF). Purpose: To examine temperature of and density of HF from the ocular surface in the eyes of patients with diabetic retinopathy (DR). Material and Methods: Sixty-two patients (123 eyes) with DR were under observation. Of these, 28 (55 eyes) and 34 (68 eyes) were diagnosed with non-proliferative DR (NPDR) and proliferative DR (PDR), respectively. They underwent a general clinical examination and measurements of temperature of the external corneal surface and density of HF from the eye. In addition, all NPDR patients underwent rheoophthalmography (ROG). Results: There was a significant difference in density of HF from the ocular surface (7.3 ± 2.1 mW/cm2 vs 6.3 ± 1.6 mW/cm2; p = 0.002), but not in ocular surface temperature (34.7 ± 1.3 °С vs 34.8 ± 1.1 °С; p = 0.8) between NPDR patients and PDR patients. HF density from the eye was positively correlated with the ocular blood volume coefficient (RQ; also named the rheographic coefficient) as assessed by ROG (r = 0.5; p = 0.01) for patients with NPDR. There was a relationship between the density of heat flux from the ocular surface and age of DR patients. Conclusion: Preliminary results suggest that (1) compared to the temperature of the ocular surface, the heat flux from the ocular surface better reflects the status of heat exchange in the eye, and (2) the technique might be promising as a diagnostic test for various pathological conditions involving impaired heat processes in the eye.

Background: Despite advances in intraocular foreign body (IOFB) diagnosis, detecting IOFB is a challenge for the ocular traumatologist. Purpose: To assess the potential of near-infrared transpalpebral transillumination (NIR TPT) for visualization of IOFB in the projection of the ciliary body to the sclera. Materials and Methods: Ten patients (10 eyes) with penetrating globe injuries associated with IOFB were under observation. All patients underwent an X-ray examination with frontal and lateral projections (both with and without using the Komberg-Baltin prosthesis), ultrasound scanning of the anterior eye and posterior eye; ultrasound distant perimetry; metal detector examination; and NIR TPT. Results: In all patients, NIR TPT visualized scleral shadows of the ciliary body pars plicata and pars plana as well as the IOFB shadow. The IOFB was localized in relation to ciliary body structures in all cases. Conclusion: NIR TPT enables non-invasive visualization of IOFBs in the anterior segment, as well as localization of these IOFBs in relation to ciliary body structures in patients with penetrating globe injury.

Background: Assessment of heat exchange processes in the human body is based on temperature and heat flux measurements. Today, there is no instrument for measuring the heat flux density from the eye. Purpose: To investigate the heat flux density from the ocular surface in healthy individuals using the developed thermoelectric device. Materials and Methods: The thermoelectric device for the measurement of heat flux from the eye has been developed within the framework of the partnership agreement between the Institute of Thermoelectricity and the Filatov Institute. Thirty-two healthy individuals (64 eyes) were under observation. Participants were divided into three age groups. They underwent a bilateral eye examination which included measurements of intraocular pressure, temperature of the external corneal surface, and heat flux density from the eye. Results: Mean room temperature during examination sessions was 21.3 ± 0.8 °С. In addition, mean temperature of the external ocular surface and mean heat flux density from the human eye were 34.6 ± 0.7°С and 7.7 ± 1.3 mW/cm2, respectively. We found that the heat flux density from the eye decreased with age in healthy subjects. Conclusion: The first ever thermoelectric device for real-time measuring of the heat flux density from the human eye was developed. The developed device was used to measure the heat flux density from the eye in healthy subjects, and to demonstrate the relationships of this characteristic with the temperature of the external ocular surface and subject age.

Background: Intraoperative intraocular media and irrigation fluid temperature monitoring is not performed during vitreoretinal surgery in current clinical practice. Purpose: To investigate intraoperative changes in intraocular temperature at the major steps of vitreoretinal surgery with irrigating solutions differing in temperature. Materials and Methods: Thirty-nine patients (39 eyes) were under observation before, during and after vitrectomy. Group 1 (20 patients; 20 eyes) and Group 2 (19 patients; 19 eyes) differed with respect to the baseline temperature (24.2 ± 0.52 °С, or 10.3 ± 1.1 °С, respectively) of the irrigating fluid. Room air temperature, irrigating fluid temperature, patient’s body temperature, blood pressure, heart rate and blood oxygen saturation, vitreous temperature, and duration of every step of the vitreoretinal procedure were recorded in all cases. Results: Vitrectomy with 24°C or 10°C irrigating solutions resulted in a substantial decrease in temperature in vitreous compartments to the level of moderate or deep hypothermia, respectively. In addition, immediately after vitrectomy, the lowest temperatures were found in the anterior vitreous, and were 30.1 ± 0.45 °С for the 24°C group and 24.37±0.52 °С for the 10°C group. Moreover, after additional surgical manipulations, in the presence of discontinued irrigation, the temperatures in the vitreous compartments were found to gradually increase. Conclusion: Vitreoretinal surgery is performed under conditions of induced uncontrolled local hypothermia, which requires intraoperative monitoring of intraocular temperature and irrigating solution temperature. During a vitroretinal procedure lasting up to 30 minutes, the intraocular contents may be safely cooled to the level of deep hypothermia.

Background: Monitoring of treatment parameters is of utmost importance in current medicine. The use of intraocular media and irrigation fluid temperature monitoring during vitreoretinal surgery is, however, not common in current clinical practice. Purpose: To investigate intraocular temperature changes at various time points of vitreoretinal surgery. Materials and Methods: Twenty patients (20 eyes) who underwent vitrectomy with room-temperature (24.2±0.52 ˚С) irrigation solutions at an ambient temperature of 24.4±0.51 °С were under observation. Temperatures in the anterior, mid- and posterior vitreous were recorded before and immediately after vitrectomy and after performance of additional surgical manipulations. Results: The presence of a transvitreous temperature gradient from the anterior toward the posterior vitreous of the human eye was confirmed. At baseline, the highest temperature (34.17±0.36 °С) was recorded in the posterior vitreous. There were significant decreases in temperatures in vitreous compartments immediately after vitrectomy, with the lowest temperature of 30.1±0.45 °С recorded in the anterior vitreous, and the greatest temperature decrease (3.8±0.59 ˚С) compared to baseline, in the preretinal posterior vitreous. There were increases in temperatures in vitreous compartments after additional surgical manipulations and, with an increase in the duration of these manipulations, temperature in the vitreous increased at an average rate of 0.18°C per minute. Conclusion: Vitreoretinal surgery is commonly performed under conditions of artificially induced local hypothermia, warranting intraoperative monitoring of intraocular and irrigation fluid temperatures.

Background: In case of controlled cryogenic destruction of an epibulbar tumor, making direct temperature measurements in the tumor and surrounding tissues during the treatment process is difficult and dangerous. Infrared thermography (IRT) is, however, capable of imaging and recording only superficial-tissue temperature changes. Mathematical modeling can be used to assess the temperature distribution in the underlying structures based on their thermal physical characteristics. Purpose: To develop a model for temperature distribution in the ocular tunics in cryogenic destruction of conjunctival tumors located within a zone involving the ciliary body, in order to determine the tunic freezing parameters enabling reduced risk of complications while meeting the principles of ablastics. Materials and Methods: Twenty-five patients (25 eyes) underwent real-time IRT during controlled cryogenic destruction of benign and malignant epibulbar lesions located in the projection of the ciliary body onto the sclera. A model for temperature distribution in the ocular tunics in cryogenic destruction of conjunctival tumors located within a ciliary body zone was implemented using Microsoft Quick BASIC Version 4.5. Results: IRT-based analysis of temperature distribution found that, in cryogenic destruction of epibulbar tumors located in the projection of the ciliary body onto the sclera, initially, the sclera surrounding the centre of exposure gradually cooled down, while the cornea started cooling down rapidly only in 30 to 60 seconds, depending on tumor size and cryogenic unit parameters. The model (a) was developed while taking into account differences in heat conduction and heat capacity between the sclera, ciliary body and cornea, and (b) was also in agreement with the above finding. Conclusion: The method for IRT-based temperature field monitoring in cryogenic destruction of epibulbar tumors, and the thermal physical model developed will allow determining the individual cryogenic exposure parameters that would prevent excessive freezing of the surrounding structures (in particular, the ciliary body and corneal endothelium). IRT allows for the assessment of post-freezing increases in ocular tissue temperature to the baseline temperature, thus contributing to reduced complication rate, should a repeat cycle of cryogenic destruction of the tumor be required. Further studies should match individual cryogenic exposure durations computed by the model to the data relating to long-term clinical outcomes.

Background: It remains poorly understood what should be the temperature of the irrigation solution for intraocular surgery and how long it is reasonable to use irrigation solutions during vitrectomy. Purpose: To investigate the structure of rabbit chorioretinal complex after vitrectomy with the use of irrigation solutions having different temperatures for 60 minutes. Materials and Methods: Twelve Chinchilla rabbits (24 eyes) were divided into two experimental groups and one control group. The two experimental groups, each of 5 rabbits (10 eyes), underwent a three-port pars plana vitrectomy with either 22°C or 5°C irrigation solution. Two intact rabbits (4 eyes) were used as controls for comparison. The duration of irrigation/aspiration was 60 minutes. Specimens for histology were obtained at days 1 and 7 after surgery. The chorioretinal complex (i.e., the choroid and retina) was histologically examined. Results: After vitrectomy with 60-minute continuous vitreous cavity cooling with either the 22°C or 5°C irrigation solution, we found retinal structural changes in the form of uneven edema, (a) predominantly in the inner retinal layers, at day 1, and (b) in both the inner and outer retinal layers, at day 7. There were destructive changes in the inner retinal layers on some slides from rabbits of both groups. In addition, the choroid appeared somewhat thickened. Conclusion: In the rabbit eyes after vitrectomy with 60-minute continuous vitreous cavity cooling with either the 22°C or 5°C irrigation solution, we found the uneven retinal edema that is likely to be mediated by aseptic inflammatory response to cooling-induced and mechanical damage to the retina, and might be also associated with the composition of the irrigation fluid.

Background: It remains poorly understood what should be the temperature of the irrigating solution for intraocular surgery and how long it is reasonable to use irrigating solutions during vitrectomy. Purpose: To investigate the structure of the rabbit chorioretinal complex after vitrectomy with the use of irrigating solutions having different temperatures for 30 minutes. Materials and Methods: Twelve Chinchilla rabbits (24 eyes) were divided into two experimental groups and one control group. The two experimental groups, each of 5 rabbits (10 eyes), underwent a three-port pars plana vitrectomy with either 22°C or 5°C irrigating solution. Two intact rabbits (4 eyes) were used as controls for comparison. The duration of irrigation/aspiration was 30 minutes. The material for histology was obtained at days 1 and 7 after surgery, and the chorioretinal complex was histologically examined by light microscopy. Results: Groups of animals subjected to thirty-minute vitreous cavity cooling with the 22 °C or 5°С irrigating solution showed no structural changes in the retinal and choroidal components compared to intact animals. Conclusion: The 22 °C or 5°С irrigating solution produces no structural changes in the retina and choroid, and can be used in the vitreoretinal surgical procedure for continuous vitreous cavity irrigation lasting for up to 30 minutes.

Background: Rhegmatogenous retinal detachment (RRD) can be complicated by choroidal detachment (CD). The state of the ciliary body in patients with RRD may indirectly indicate active intraocular inflammation. Purpose: To investigate ciliary body dimensions in RRD complicated by CD after preoperative anti-inflammatory treatment. Materials and Methods: This study included 31 RRD+CD patients (31 eyes) with an intact fellow eye who were under observation. Before the vitrectomy, they received 4-mg intravitreal triamcinolone (IVT), either alone or in combination with 0.5 to 0.8 mL of perfluorpropane. Near-infrared transpalpebral transillumination (NIR TPT) and ultrasound biomicroscopy (UBM) of anterior eye structures were performed before and 1, 2, 3 or 4 days after preoperative intravitreal therapy. Results: Mean baseline width and mean baseline thickness of the pars plicata in eyes with combined RRD and CD were statistically significantly greater than in intact fellow eyes (2.4 ± 0.1 mm versus 1.9 ± 0.1 mm, P = 0.01, and 0.83 ± 0.1 mm versus 0.65 ± 0.1 mm, P = 0.02, respectively). Mean post-treatment pars plana width in the affected eyes having axial length > 25.0 mm was 4.74 ± 0.63 mm, and the percentage of these eyes was 64.5% among eyes with combined RRD and CD. Mean thickness and mean width of the pars plicata in the affected eyes after treatment were 2.2 ± 0.1 mm и 0.66 ± 0.1 mm, respectively. Conclusions: In eyes with combined RRD and CD, pars plicata width and thickness were greater than in intact fellow eyes. Ciliary body detachment tends to occur in longer eyes (therefore, those with a greater pars plana width) with RRD. In eyes with combined RRD and CD, there was evidence of re-attachment of the pars plana as well as reduction in pars plicata thickness and width after preoperative anti-inflammatory treatment.

Background: Ciliary body size may be objectively assessed by ultrasound scanning and near-infrared transpalpebral transillumination. Purpose: To investigate the dimensions of ciliary body structures in various axial eye lengths in patients with rhegmatogenous retinal detachment (RRD). Materials and Methods: This study included 35 RRD patients (35 eyes) with an intact fellow eye who were under observation. These were divided into three groups, based on axial length of the eye with RRD. All patients underwent near-infrared transpalpebral transillumination (NIR TPT) and ultrasound scanning of the anterior eye. Results: In patients with axial length ranging from 20 mm to 22.9 mm, 23 mm to 24.9 mm, and larger than 25 mm, pars plana width was 3.4 mm, 4.16 mm, and 4.95 mm, respectively, whereas pars plicata width was 1.9 mm, 1.99 mm, and 2.0 mm, respectively, and pars plicata thickness was 0.75 mm, 0.75 mm, and 0.72 mm, respectively. Conclusions: A direct relationship exists between pars plana width and axial length, but pars plicata thickness and width do not depend on the axial length in eyes with RRD. There was no difference in pars plana width or pars plicata width between the eye with RRD and unaffected fellow eye. In the eye with RRD, the pars plicata thickness was thicker than that in the intact fellow eye, which may evidence the presence of intraocular inflammation.

Background: There is no unanimously adopted approach to titrating laser parameters in subthreshold retinal laser photocoagulation without ophthalmoscopically visible fundus changes. Purpose: To compare the ultrastructural changes in the rabbit chorioretinal complex after various modes of 577-nm and 532-nm laser photocoagulation. Materials and Methods: Ten rabbits (20 eyes) were involved in the experimental study. Eight (10 eyes) of them underwent different modes of 577-nm or 532-nm laser photocoagulation, and were euthanized at postlaser days 1 (4 rabbits) or 14 (4 rabbits). Ultra-thin sections of their ocular tissue specimens were subjected to electron microscopy and assessed for the state of their choriocapillaries, RPE and photoreceptor cells. In addition, 2 intact rabbits (4 eyes) were used as controls for comparison. Results: 577-nm or 532-nm conventional RLPC resulted in damage to RPE cells, all photoreceptor compartments and choriocapillaries; 577-nm or 532-nm selective RLPC resulted in damage to RPE cells and photoreceptor outer and inner segments, and 577-nm micropulse RLPC with the power setting adjusted to 50% threshold resulted in damage mostly to apical aspects of RPE cells and photoreceptor outer segments. Conclusion: 577-nm micropulse RLPC with the power setting adjusted to 50% threshold is a more photoreceptor- and choriocapillaris-sparing approach compared to 577-nm or 532-nm conventional and selective RLPC, and can be used in clinical practice as a laser treatment approach with the least invasive effect on the chorioretinal complex.

Background: There is no unanimously adopted approach to titrating laser settings in subthreshold retinal laser photocoagulation (LPC) without ophthalmoscopically visible fundus changes. The efficacy of this approach to treatment of retinal diseases is still to be investigated. Purpose: To investigate the efficacy of 577-nm RPE LPC in the treatment of age-related maculopathy (ARM) with various extents of morphological and functional loss. Materials and Methods: The study involved 57 patients (57 eyes) diagnosed with ARM. 577-nm micropulse laser photocoagulation was applied to the RPE at the macula. Patients were followed-up for 12 months. Results: Three groups of ARM eyes with a similar extent of morphological and functional loss at baseline were created using Ward’s clustering method. Changes in visual acuity, retinal foveal thickness diameter and height of macular drusen, as well as incidences of subretinal neovascularization (SNV) and geographic atrophy over the follow-up for the groups were investigated. We observed no cases of SNV or geographic atrophy during the follow-up. Conclusions: 577-nm micropulse RPE laser photocoagulation with power titrated in micropulse mode was found to be efficacious and safe treatment for ARM patients with a wide variation in the extent of morphological and functional loss, including patients with drusenoid pigment epithelium detachment.

Background: There is no unanimously adopted approach to titrating laser parameters in subthreshold retinal laser photocoagulation without ophthalmoscopically visible fundus changes. Purpose: To investigate the ultrastructural changes in the rabbit chorioretinal complex following 577-nm conventional, selective or micropulse retinal laser photocoagulation (RLPC). Materials and Methods: Four rabbits (8 eyes) were involved in the experimental study and underwent the RLPC modes with the 577-nm system (Supra 577). Rabbits (n = 2/time point) were euthanized at postlaser days 1 and 14. Ultra-thin sections of their ocular tissue specimens were subjected to electron microscopy. In addition, 2 intact rabbits (4 eyes) were used as controls for comparison. Results: Conventional RLPC resulted in damage to RPE cells, all photoreceptor compartments and choriocapillaries; selective RLPC resulted in damage to RPE cells and photoreceptor outer and inner segments; and micropulse RLPC with the power setting adjusted to 50% threshold resulted in damage mostly to apical aspects of RPE cells and photoreceptor outer segments. Conclusion: 577-nm micropulse RLPC with the power setting adjusted to 50% threshold is a more photoreceptor- and choriocapillaris-sparing approach compared to conventional and selective RLPC, and can be used in clinical practice as a laser treatment approach with the least invasive effect on the chorioretinal complex.

Background: Although a variety of approaches are available for treating retinal pigment epithelial detachment (PED) associated with age-related macular degeneration (AMD), no unified methodology has yet been approved and/or overwhelmingly favored. Purpose: To investigate the effect of a long-acting steroid on the structural and functional RPE features in serous PED associated with AMD in long-term follow-up study, and to improve the efficacy of treatment of this disorder through the use of steroid therapy based on the findings of this investigation. Materials and Methods: Fifty-two patients (54 eyes) with serous PED associated with AMD were followed up for 36 months. They were divided into subtenon and intravitreal groups comprising 30 patients (32 eyes) and 22 patients (22 eyes), respectively, and treated with 0.5 ml (40 mg) subtenon triamcinolone acetonide (TA) suspension and 0.1 ml (4 mg) intravitreal TA crystals, respectively, as needed. Results: We found significant reductions in the height and length of PED in the intravitreal group (from 486 (SD 187) µm to 256 (SD 139) µm, P = 0.005; and from 1859 (SD 911) µm to 1112 (SD 451) µm, P = 0.04, respectively) and in the subtenon group (from 446 (SD 199) µm to 231 (SD 107) µm, P = 0.0001; and from 2055 (SD 587) µm to 1423 (SD 465) µm, P = 0.02, respectively). In study eyes, the visual acuity remained stable throughout the 36-month follow-up period, irrespective of the route of administration of TA. Conclusion: The use of subtenon and intravitreal TA in serous PED associated with AMD is efficacious for maintaining the anatomical structure of the retina.

Introduction. Today the question of temperature distribution in various eye segments of human and animals remains understudied. Objective. To design the device for measuring intraocular temperature and to study in the experiment the principle of temperature distribution in various segments of rabbit eye. Material and methods. Experiment was carried out on 11 rabbits (22 eyes). For temperature measurement the thermoelectric device was designed, which consists of temperature registration module, measure probes of 0.7 mm in diameter and computer with software. Results. Under ambient temperature 23.8°C, the temperature of various eye segments was the following: posterior fornix of conjunctiva ? 37.41°C; anterior fornix of conjunctiva ? 36.82оС; cornea surface ? 34.41оС; ocular anterior chamber ? 35.97оС; anterior part of vitreous ? 36.96оС; of middle part of vitreous ? 37.40оС; back part of vitreous ? 37.50оС; of retina/ vascular membrane ? 37.64оС; subtenon area ? 37.78оС. Temperature difference of cornea external surface and ocular anterior chamber was 1.56оС, and of cornea external surface and retina was 3.23оС. Conclusion. Thermoelectric device, which helps to make measurements in various eye segments, was designed. Due to this device the temperature distribution in rabbit eye was studied in vivo.